Version:  2.0.40 2.2.26 2.4.37 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16

Linux/drivers/staging/fwserial/fwserial.c

  1 /*
  2  * FireWire Serial driver
  3  *
  4  * Copyright (C) 2012 Peter Hurley <peter@hurleysoftware.com>
  5  *
  6  * This program is free software; you can redistribute it and/or modify
  7  * it under the terms of the GNU General Public License as published by
  8  * the Free Software Foundation; either version 2 of the License, or
  9  * (at your option) any later version.
 10  *
 11  * This program is distributed in the hope that it will be useful,
 12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14  * GNU General Public License for more details.
 15  */
 16 
 17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 18 
 19 #include <linux/sched.h>
 20 #include <linux/slab.h>
 21 #include <linux/device.h>
 22 #include <linux/mod_devicetable.h>
 23 #include <linux/rculist.h>
 24 #include <linux/workqueue.h>
 25 #include <linux/ratelimit.h>
 26 #include <linux/bug.h>
 27 #include <linux/uaccess.h>
 28 
 29 #include "fwserial.h"
 30 
 31 #define be32_to_u64(hi, lo)  ((u64)be32_to_cpu(hi) << 32 | be32_to_cpu(lo))
 32 
 33 #define LINUX_VENDOR_ID   0xd00d1eU  /* same id used in card root directory   */
 34 #define FWSERIAL_VERSION  0x00e81cU  /* must be unique within LINUX_VENDOR_ID */
 35 
 36 /* configurable options */
 37 static int num_ttys = 4;            /* # of std ttys to create per fw_card    */
 38                                     /* - doubles as loopback port index       */
 39 static bool auto_connect = true;    /* try to VIRT_CABLE to every peer        */
 40 static bool create_loop_dev = true; /* create a loopback device for each card */
 41 
 42 module_param_named(ttys, num_ttys, int, S_IRUGO | S_IWUSR);
 43 module_param_named(auto, auto_connect, bool, S_IRUGO | S_IWUSR);
 44 module_param_named(loop, create_loop_dev, bool, S_IRUGO | S_IWUSR);
 45 
 46 /*
 47  * Threshold below which the tty is woken for writing
 48  * - should be equal to WAKEUP_CHARS in drivers/tty/n_tty.c because
 49  *   even if the writer is woken, n_tty_poll() won't set POLLOUT until
 50  *   our fifo is below this level
 51  */
 52 #define WAKEUP_CHARS             256
 53 
 54 /**
 55  * fwserial_list: list of every fw_serial created for each fw_card
 56  * See discussion in fwserial_probe.
 57  */
 58 static LIST_HEAD(fwserial_list);
 59 static DEFINE_MUTEX(fwserial_list_mutex);
 60 
 61 /**
 62  * port_table: array of tty ports allocated to each fw_card
 63  *
 64  * tty ports are allocated during probe when an fw_serial is first
 65  * created for a given fw_card. Ports are allocated in a contiguous block,
 66  * each block consisting of 'num_ports' ports.
 67  */
 68 static struct fwtty_port *port_table[MAX_TOTAL_PORTS];
 69 static DEFINE_MUTEX(port_table_lock);
 70 static bool port_table_corrupt;
 71 #define FWTTY_INVALID_INDEX  MAX_TOTAL_PORTS
 72 
 73 #define loop_idx(port)  (((port)->index) / num_ports)
 74 #define table_idx(loop) ((loop) * num_ports + num_ttys)
 75 
 76 /* total # of tty ports created per fw_card */
 77 static int num_ports;
 78 
 79 /* slab used as pool for struct fwtty_transactions */
 80 static struct kmem_cache *fwtty_txn_cache;
 81 
 82 struct tty_driver *fwtty_driver;
 83 static struct tty_driver *fwloop_driver;
 84 
 85 static struct dentry *fwserial_debugfs;
 86 
 87 struct fwtty_transaction;
 88 typedef void (*fwtty_transaction_cb)(struct fw_card *card, int rcode,
 89                                      void *data, size_t length,
 90                                      struct fwtty_transaction *txn);
 91 
 92 struct fwtty_transaction {
 93         struct fw_transaction      fw_txn;
 94         fwtty_transaction_cb       callback;
 95         struct fwtty_port          *port;
 96         union {
 97                 struct dma_pending dma_pended;
 98         };
 99 };
100 
101 #define to_device(a, b)                 (a->b)
102 #define fwtty_err(p, fmt, ...)                                          \
103         dev_err(to_device(p, device), fmt, ##__VA_ARGS__)
104 #define fwtty_info(p, fmt, ...)                                         \
105         dev_info(to_device(p, device), fmt, ##__VA_ARGS__)
106 #define fwtty_notice(p, fmt, ...)                                       \
107         dev_notice(to_device(p, device), fmt, ##__VA_ARGS__)
108 #define fwtty_dbg(p, fmt, ...)                                          \
109         dev_dbg(to_device(p, device), "%s: " fmt, __func__, ##__VA_ARGS__)
110 #define fwtty_err_ratelimited(p, fmt, ...)                              \
111         dev_err_ratelimited(to_device(p, device), fmt, ##__VA_ARGS__)
112 
113 #ifdef DEBUG
114 static inline void debug_short_write(struct fwtty_port *port, int c, int n)
115 {
116         int avail;
117 
118         if (n < c) {
119                 spin_lock_bh(&port->lock);
120                 avail = dma_fifo_avail(&port->tx_fifo);
121                 spin_unlock_bh(&port->lock);
122                 fwtty_dbg(port, "short write: avail:%d req:%d wrote:%d\n",
123                           avail, c, n);
124         }
125 }
126 #else
127 #define debug_short_write(port, c, n)
128 #endif
129 
130 static struct fwtty_peer *__fwserial_peer_by_node_id(struct fw_card *card,
131                                                      int generation, int id);
132 
133 #ifdef FWTTY_PROFILING
134 
135 static void fwtty_profile_fifo(struct fwtty_port *port, unsigned *stat)
136 {
137         spin_lock_bh(&port->lock);
138         fwtty_profile_data(stat, dma_fifo_avail(&port->tx_fifo));
139         spin_unlock_bh(&port->lock);
140 }
141 
142 static void fwtty_dump_profile(struct seq_file *m, struct stats *stats)
143 {
144         /* for each stat, print sum of 0 to 2^k, then individually */
145         int k = 4;
146         unsigned sum;
147         int j;
148         char t[10];
149 
150         snprintf(t, 10, "< %d", 1 << k);
151         seq_printf(m, "\n%14s  %6s", " ", t);
152         for (j = k + 1; j < DISTRIBUTION_MAX_INDEX; ++j)
153                 seq_printf(m, "%6d", 1 << j);
154 
155         ++k;
156         for (j = 0, sum = 0; j <= k; ++j)
157                 sum += stats->reads[j];
158         seq_printf(m, "\n%14s: %6d", "reads", sum);
159         for (j = k + 1; j <= DISTRIBUTION_MAX_INDEX; ++j)
160                 seq_printf(m, "%6d", stats->reads[j]);
161 
162         for (j = 0, sum = 0; j <= k; ++j)
163                 sum += stats->writes[j];
164         seq_printf(m, "\n%14s: %6d", "writes", sum);
165         for (j = k + 1; j <= DISTRIBUTION_MAX_INDEX; ++j)
166                 seq_printf(m, "%6d", stats->writes[j]);
167 
168         for (j = 0, sum = 0; j <= k; ++j)
169                 sum += stats->txns[j];
170         seq_printf(m, "\n%14s: %6d", "txns", sum);
171         for (j = k + 1; j <= DISTRIBUTION_MAX_INDEX; ++j)
172                 seq_printf(m, "%6d", stats->txns[j]);
173 
174         for (j = 0, sum = 0; j <= k; ++j)
175                 sum += stats->unthrottle[j];
176         seq_printf(m, "\n%14s: %6d", "avail @ unthr", sum);
177         for (j = k + 1; j <= DISTRIBUTION_MAX_INDEX; ++j)
178                 seq_printf(m, "%6d", stats->unthrottle[j]);
179 }
180 
181 #else
182 #define fwtty_profile_fifo(port, stat)
183 #define fwtty_dump_profile(m, stats)
184 #endif
185 
186 /*
187  * Returns the max receive packet size for the given node
188  * Devices which are OHCI v1.0/ v1.1/ v1.2-draft or RFC 2734 compliant
189  * are required by specification to support max_rec of 8 (512 bytes) or more.
190  */
191 static inline int device_max_receive(struct fw_device *fw_device)
192 {
193         /* see IEEE 1394-2008 table 8-8 */
194         return min(2 << fw_device->max_rec, 4096);
195 }
196 
197 static void fwtty_log_tx_error(struct fwtty_port *port, int rcode)
198 {
199         switch (rcode) {
200         case RCODE_SEND_ERROR:
201                 fwtty_err_ratelimited(port, "card busy\n");
202                 break;
203         case RCODE_ADDRESS_ERROR:
204                 fwtty_err_ratelimited(port, "bad unit addr or write length\n");
205                 break;
206         case RCODE_DATA_ERROR:
207                 fwtty_err_ratelimited(port, "failed rx\n");
208                 break;
209         case RCODE_NO_ACK:
210                 fwtty_err_ratelimited(port, "missing ack\n");
211                 break;
212         case RCODE_BUSY:
213                 fwtty_err_ratelimited(port, "remote busy\n");
214                 break;
215         default:
216                 fwtty_err_ratelimited(port, "failed tx: %d\n", rcode);
217         }
218 }
219 
220 static void fwtty_txn_constructor(void *this)
221 {
222         struct fwtty_transaction *txn = this;
223 
224         init_timer(&txn->fw_txn.split_timeout_timer);
225 }
226 
227 static void fwtty_common_callback(struct fw_card *card, int rcode,
228                                   void *payload, size_t len, void *cb_data)
229 {
230         struct fwtty_transaction *txn = cb_data;
231         struct fwtty_port *port = txn->port;
232 
233         if (port && rcode != RCODE_COMPLETE)
234                 fwtty_log_tx_error(port, rcode);
235         if (txn->callback)
236                 txn->callback(card, rcode, payload, len, txn);
237         kmem_cache_free(fwtty_txn_cache, txn);
238 }
239 
240 static int fwtty_send_data_async(struct fwtty_peer *peer, int tcode,
241                                  unsigned long long addr, void *payload,
242                                  size_t len, fwtty_transaction_cb callback,
243                                  struct fwtty_port *port)
244 {
245         struct fwtty_transaction *txn;
246         int generation;
247 
248         txn = kmem_cache_alloc(fwtty_txn_cache, GFP_ATOMIC);
249         if (!txn)
250                 return -ENOMEM;
251 
252         txn->callback = callback;
253         txn->port = port;
254 
255         generation = peer->generation;
256         smp_rmb();
257         fw_send_request(peer->serial->card, &txn->fw_txn, tcode,
258                         peer->node_id, generation, peer->speed, addr, payload,
259                         len, fwtty_common_callback, txn);
260         return 0;
261 }
262 
263 static void fwtty_send_txn_async(struct fwtty_peer *peer,
264                                  struct fwtty_transaction *txn, int tcode,
265                                  unsigned long long addr, void *payload,
266                                  size_t len, fwtty_transaction_cb callback,
267                                  struct fwtty_port *port)
268 {
269         int generation;
270 
271         txn->callback = callback;
272         txn->port = port;
273 
274         generation = peer->generation;
275         smp_rmb();
276         fw_send_request(peer->serial->card, &txn->fw_txn, tcode,
277                         peer->node_id, generation, peer->speed, addr, payload,
278                         len, fwtty_common_callback, txn);
279 }
280 
281 
282 static void __fwtty_restart_tx(struct fwtty_port *port)
283 {
284         int len, avail;
285 
286         len = dma_fifo_out_level(&port->tx_fifo);
287         if (len)
288                 schedule_delayed_work(&port->drain, 0);
289         avail = dma_fifo_avail(&port->tx_fifo);
290 
291         fwtty_dbg(port, "fifo len: %d avail: %d\n", len, avail);
292 }
293 
294 static void fwtty_restart_tx(struct fwtty_port *port)
295 {
296         spin_lock_bh(&port->lock);
297         __fwtty_restart_tx(port);
298         spin_unlock_bh(&port->lock);
299 }
300 
301 /**
302  * fwtty_update_port_status - decodes & dispatches line status changes
303  *
304  * Note: in loopback, the port->lock is being held. Only use functions that
305  * don't attempt to reclaim the port->lock.
306  */
307 static void fwtty_update_port_status(struct fwtty_port *port, unsigned status)
308 {
309         unsigned delta;
310         struct tty_struct *tty;
311 
312         /* simulated LSR/MSR status from remote */
313         status &= ~MCTRL_MASK;
314         delta = (port->mstatus ^ status) & ~MCTRL_MASK;
315         delta &= ~(status & TIOCM_RNG);
316         port->mstatus = status;
317 
318         if (delta & TIOCM_RNG)
319                 ++port->icount.rng;
320         if (delta & TIOCM_DSR)
321                 ++port->icount.dsr;
322         if (delta & TIOCM_CAR)
323                 ++port->icount.dcd;
324         if (delta & TIOCM_CTS)
325                 ++port->icount.cts;
326 
327         fwtty_dbg(port, "status: %x delta: %x\n", status, delta);
328 
329         if (delta & TIOCM_CAR) {
330                 tty = tty_port_tty_get(&port->port);
331                 if (tty && !C_CLOCAL(tty)) {
332                         if (status & TIOCM_CAR)
333                                 wake_up_interruptible(&port->port.open_wait);
334                         else
335                                 schedule_work(&port->hangup);
336                 }
337                 tty_kref_put(tty);
338         }
339 
340         if (delta & TIOCM_CTS) {
341                 tty = tty_port_tty_get(&port->port);
342                 if (tty && C_CRTSCTS(tty)) {
343                         if (tty->hw_stopped) {
344                                 if (status & TIOCM_CTS) {
345                                         tty->hw_stopped = 0;
346                                         if (port->loopback)
347                                                 __fwtty_restart_tx(port);
348                                         else
349                                                 fwtty_restart_tx(port);
350                                 }
351                         } else {
352                                 if (~status & TIOCM_CTS)
353                                         tty->hw_stopped = 1;
354                         }
355                 }
356                 tty_kref_put(tty);
357 
358         } else if (delta & OOB_TX_THROTTLE) {
359                 tty = tty_port_tty_get(&port->port);
360                 if (tty) {
361                         if (tty->hw_stopped) {
362                                 if (~status & OOB_TX_THROTTLE) {
363                                         tty->hw_stopped = 0;
364                                         if (port->loopback)
365                                                 __fwtty_restart_tx(port);
366                                         else
367                                                 fwtty_restart_tx(port);
368                                 }
369                         } else {
370                                 if (status & OOB_TX_THROTTLE)
371                                         tty->hw_stopped = 1;
372                         }
373                 }
374                 tty_kref_put(tty);
375         }
376 
377         if (delta & (UART_LSR_BI << 24)) {
378                 if (status & (UART_LSR_BI << 24)) {
379                         port->break_last = jiffies;
380                         schedule_delayed_work(&port->emit_breaks, 0);
381                 } else {
382                         /* run emit_breaks one last time (if pending) */
383                         mod_delayed_work(system_wq, &port->emit_breaks, 0);
384                 }
385         }
386 
387         if (delta & (TIOCM_DSR | TIOCM_CAR | TIOCM_CTS | TIOCM_RNG))
388                 wake_up_interruptible(&port->port.delta_msr_wait);
389 }
390 
391 /**
392  * __fwtty_port_line_status - generate 'line status' for indicated port
393  *
394  * This function returns a remote 'MSR' state based on the local 'MCR' state,
395  * as if a null modem cable was attached. The actual status is a mangling
396  * of TIOCM_* bits suitable for sending to a peer's status_addr.
397  *
398  * Note: caller must be holding port lock
399  */
400 static unsigned __fwtty_port_line_status(struct fwtty_port *port)
401 {
402         unsigned status = 0;
403 
404         /* TODO: add module param to tie RNG to DTR as well */
405 
406         if (port->mctrl & TIOCM_DTR)
407                 status |= TIOCM_DSR | TIOCM_CAR;
408         if (port->mctrl & TIOCM_RTS)
409                 status |= TIOCM_CTS;
410         if (port->mctrl & OOB_RX_THROTTLE)
411                 status |= OOB_TX_THROTTLE;
412         /* emulate BRK as add'l line status */
413         if (port->break_ctl)
414                 status |= UART_LSR_BI << 24;
415 
416         return status;
417 }
418 
419 /**
420  * __fwtty_write_port_status - send the port line status to peer
421  *
422  * Note: caller must be holding the port lock.
423  */
424 static int __fwtty_write_port_status(struct fwtty_port *port)
425 {
426         struct fwtty_peer *peer;
427         int err = -ENOENT;
428         unsigned status = __fwtty_port_line_status(port);
429 
430         rcu_read_lock();
431         peer = rcu_dereference(port->peer);
432         if (peer) {
433                 err = fwtty_send_data_async(peer, TCODE_WRITE_QUADLET_REQUEST,
434                                             peer->status_addr, &status,
435                                             sizeof(status), NULL, port);
436         }
437         rcu_read_unlock();
438 
439         return err;
440 }
441 
442 /**
443  * fwtty_write_port_status - same as above but locked by port lock
444  */
445 static int fwtty_write_port_status(struct fwtty_port *port)
446 {
447         int err;
448 
449         spin_lock_bh(&port->lock);
450         err = __fwtty_write_port_status(port);
451         spin_unlock_bh(&port->lock);
452         return err;
453 }
454 
455 static void fwtty_throttle_port(struct fwtty_port *port)
456 {
457         struct tty_struct *tty;
458         unsigned old;
459 
460         tty = tty_port_tty_get(&port->port);
461         if (!tty)
462                 return;
463 
464         spin_lock_bh(&port->lock);
465 
466         old = port->mctrl;
467         port->mctrl |= OOB_RX_THROTTLE;
468         if (C_CRTSCTS(tty))
469                 port->mctrl &= ~TIOCM_RTS;
470         if (~old & OOB_RX_THROTTLE)
471                 __fwtty_write_port_status(port);
472 
473         spin_unlock_bh(&port->lock);
474 
475         tty_kref_put(tty);
476 }
477 
478 /**
479  * fwtty_do_hangup - wait for ldisc to deliver all pending rx; only then hangup
480  *
481  * When the remote has finished tx, and all in-flight rx has been received and
482  * and pushed to the flip buffer, the remote may close its device. This will
483  * drop DTR on the remote which will drop carrier here. Typically, the tty is
484  * hung up when carrier is dropped or lost.
485  *
486  * However, there is a race between the hang up and the line discipline
487  * delivering its data to the reader. A hangup will cause the ldisc to flush
488  * (ie., clear) the read buffer and flip buffer. Because of firewire's
489  * relatively high throughput, the ldisc frequently lags well behind the driver,
490  * resulting in lost data (which has already been received and written to
491  * the flip buffer) when the remote closes its end.
492  *
493  * Unfortunately, since the flip buffer offers no direct method for determining
494  * if it holds data, ensuring the ldisc has delivered all data is problematic.
495  */
496 
497 /* FIXME: drop this workaround when __tty_hangup waits for ldisc completion */
498 static void fwtty_do_hangup(struct work_struct *work)
499 {
500         struct fwtty_port *port = to_port(work, hangup);
501         struct tty_struct *tty;
502 
503         schedule_timeout_uninterruptible(msecs_to_jiffies(50));
504 
505         tty = tty_port_tty_get(&port->port);
506         if (tty)
507                 tty_vhangup(tty);
508         tty_kref_put(tty);
509 }
510 
511 
512 static void fwtty_emit_breaks(struct work_struct *work)
513 {
514         struct fwtty_port *port = to_port(to_delayed_work(work), emit_breaks);
515         static const char buf[16];
516         unsigned long now = jiffies;
517         unsigned long elapsed = now - port->break_last;
518         int n, t, c, brk = 0;
519 
520         /* generate breaks at the line rate (but at least 1) */
521         n = (elapsed * port->cps) / HZ + 1;
522         port->break_last = now;
523 
524         fwtty_dbg(port, "sending %d brks\n", n);
525 
526         while (n) {
527                 t = min(n, 16);
528                 c = tty_insert_flip_string_fixed_flag(&port->port, buf,
529                                                       TTY_BREAK, t);
530                 n -= c;
531                 brk += c;
532                 if (c < t)
533                         break;
534         }
535         tty_flip_buffer_push(&port->port);
536 
537         if (port->mstatus & (UART_LSR_BI << 24))
538                 schedule_delayed_work(&port->emit_breaks, FREQ_BREAKS);
539         port->icount.brk += brk;
540 }
541 
542 static int fwtty_rx(struct fwtty_port *port, unsigned char *data, size_t len)
543 {
544         int c, n = len;
545         unsigned lsr;
546         int err = 0;
547 
548         fwtty_dbg(port, "%d\n", n);
549         fwtty_profile_data(port->stats.reads, n);
550 
551         if (port->write_only) {
552                 n = 0;
553                 goto out;
554         }
555 
556         /* disregard break status; breaks are generated by emit_breaks work */
557         lsr = (port->mstatus >> 24) & ~UART_LSR_BI;
558 
559         if (port->overrun)
560                 lsr |= UART_LSR_OE;
561 
562         if (lsr & UART_LSR_OE)
563                 ++port->icount.overrun;
564 
565         lsr &= port->status_mask;
566         if (lsr & ~port->ignore_mask & UART_LSR_OE) {
567                 if (!tty_insert_flip_char(&port->port, 0, TTY_OVERRUN)) {
568                         err = -EIO;
569                         goto out;
570                 }
571         }
572         port->overrun = false;
573 
574         if (lsr & port->ignore_mask & ~UART_LSR_OE) {
575                 /* TODO: don't drop SAK and Magic SysRq here */
576                 n = 0;
577                 goto out;
578         }
579 
580         c = tty_insert_flip_string_fixed_flag(&port->port, data, TTY_NORMAL, n);
581         if (c > 0)
582                 tty_flip_buffer_push(&port->port);
583         n -= c;
584 
585         if (n) {
586                 port->overrun = true;
587                 err = -EIO;
588                 fwtty_err_ratelimited(port, "flip buffer overrun\n");
589 
590         } else {
591                 /* throttle the sender if remaining flip buffer space has
592                  * reached high watermark to avoid losing data which may be
593                  * in-flight. Since the AR request context is 32k, that much
594                  * data may have _already_ been acked.
595                  */
596                 if (tty_buffer_space_avail(&port->port) < HIGH_WATERMARK)
597                         fwtty_throttle_port(port);
598         }
599 
600 out:
601         port->icount.rx += len;
602         port->stats.lost += n;
603         return err;
604 }
605 
606 /**
607  * fwtty_port_handler - bus address handler for port reads/writes
608  * @parameters: fw_address_callback_t as specified by firewire core interface
609  *
610  * This handler is responsible for handling inbound read/write dma from remotes.
611  */
612 static void fwtty_port_handler(struct fw_card *card,
613                                struct fw_request *request,
614                                int tcode, int destination, int source,
615                                int generation,
616                                unsigned long long addr,
617                                void *data, size_t len,
618                                void *callback_data)
619 {
620         struct fwtty_port *port = callback_data;
621         struct fwtty_peer *peer;
622         int err;
623         int rcode;
624 
625         /* Only accept rx from the peer virtual-cabled to this port */
626         rcu_read_lock();
627         peer = __fwserial_peer_by_node_id(card, generation, source);
628         rcu_read_unlock();
629         if (!peer || peer != rcu_access_pointer(port->peer)) {
630                 rcode = RCODE_ADDRESS_ERROR;
631                 fwtty_err_ratelimited(port, "ignoring unauthenticated data\n");
632                 goto respond;
633         }
634 
635         switch (tcode) {
636         case TCODE_WRITE_QUADLET_REQUEST:
637                 if (addr != port->rx_handler.offset || len != 4) {
638                         rcode = RCODE_ADDRESS_ERROR;
639                 } else {
640                         fwtty_update_port_status(port, *(unsigned *)data);
641                         rcode = RCODE_COMPLETE;
642                 }
643                 break;
644 
645         case TCODE_WRITE_BLOCK_REQUEST:
646                 if (addr != port->rx_handler.offset + 4 ||
647                     len > port->rx_handler.length - 4) {
648                         rcode = RCODE_ADDRESS_ERROR;
649                 } else {
650                         err = fwtty_rx(port, data, len);
651                         switch (err) {
652                         case 0:
653                                 rcode = RCODE_COMPLETE;
654                                 break;
655                         case -EIO:
656                                 rcode = RCODE_DATA_ERROR;
657                                 break;
658                         default:
659                                 rcode = RCODE_CONFLICT_ERROR;
660                                 break;
661                         }
662                 }
663                 break;
664 
665         default:
666                 rcode = RCODE_TYPE_ERROR;
667         }
668 
669 respond:
670         fw_send_response(card, request, rcode);
671 }
672 
673 /**
674  * fwtty_tx_complete - callback for tx dma
675  * @data: ignored, has no meaning for write txns
676  * @length: ignored, has no meaning for write txns
677  *
678  * The writer must be woken here if the fifo has been emptied because it
679  * may have slept if chars_in_buffer was != 0
680  */
681 static void fwtty_tx_complete(struct fw_card *card, int rcode,
682                               void *data, size_t length,
683                               struct fwtty_transaction *txn)
684 {
685         struct fwtty_port *port = txn->port;
686         int len;
687 
688         fwtty_dbg(port, "rcode: %d\n", rcode);
689 
690         switch (rcode) {
691         case RCODE_COMPLETE:
692                 spin_lock_bh(&port->lock);
693                 dma_fifo_out_complete(&port->tx_fifo, &txn->dma_pended);
694                 len = dma_fifo_level(&port->tx_fifo);
695                 spin_unlock_bh(&port->lock);
696 
697                 port->icount.tx += txn->dma_pended.len;
698                 break;
699 
700         default:
701                 /* TODO: implement retries */
702                 spin_lock_bh(&port->lock);
703                 dma_fifo_out_complete(&port->tx_fifo, &txn->dma_pended);
704                 len = dma_fifo_level(&port->tx_fifo);
705                 spin_unlock_bh(&port->lock);
706 
707                 port->stats.dropped += txn->dma_pended.len;
708         }
709 
710         if (len < WAKEUP_CHARS)
711                 tty_port_tty_wakeup(&port->port);
712 }
713 
714 static int fwtty_tx(struct fwtty_port *port, bool drain)
715 {
716         struct fwtty_peer *peer;
717         struct fwtty_transaction *txn;
718         struct tty_struct *tty;
719         int n, len;
720 
721         tty = tty_port_tty_get(&port->port);
722         if (!tty)
723                 return -ENOENT;
724 
725         rcu_read_lock();
726         peer = rcu_dereference(port->peer);
727         if (!peer) {
728                 n = -EIO;
729                 goto out;
730         }
731 
732         if (test_and_set_bit(IN_TX, &port->flags)) {
733                 n = -EALREADY;
734                 goto out;
735         }
736 
737         /* try to write as many dma transactions out as possible */
738         n = -EAGAIN;
739         while (!tty->stopped && !tty->hw_stopped &&
740                !test_bit(STOP_TX, &port->flags)) {
741                 txn = kmem_cache_alloc(fwtty_txn_cache, GFP_ATOMIC);
742                 if (!txn) {
743                         n = -ENOMEM;
744                         break;
745                 }
746 
747                 spin_lock_bh(&port->lock);
748                 n = dma_fifo_out_pend(&port->tx_fifo, &txn->dma_pended);
749                 spin_unlock_bh(&port->lock);
750 
751                 fwtty_dbg(port, "out: %u rem: %d\n", txn->dma_pended.len, n);
752 
753                 if (n < 0) {
754                         kmem_cache_free(fwtty_txn_cache, txn);
755                         if (n == -EAGAIN) {
756                                 ++port->stats.tx_stall;
757                         } else if (n == -ENODATA) {
758                                 fwtty_profile_data(port->stats.txns, 0);
759                         } else {
760                                 ++port->stats.fifo_errs;
761                                 fwtty_err_ratelimited(port, "fifo err: %d\n",
762                                                       n);
763                         }
764                         break;
765                 }
766 
767                 fwtty_profile_data(port->stats.txns, txn->dma_pended.len);
768 
769                 fwtty_send_txn_async(peer, txn, TCODE_WRITE_BLOCK_REQUEST,
770                                      peer->fifo_addr, txn->dma_pended.data,
771                                      txn->dma_pended.len, fwtty_tx_complete,
772                                      port);
773                 ++port->stats.sent;
774 
775                 /*
776                  * Stop tx if the 'last view' of the fifo is empty or if
777                  * this is the writer and there's not enough data to bother
778                  */
779                 if (n == 0 || (!drain && n < WRITER_MINIMUM))
780                         break;
781         }
782 
783         if (n >= 0 || n == -EAGAIN || n == -ENOMEM || n == -ENODATA) {
784                 spin_lock_bh(&port->lock);
785                 len = dma_fifo_out_level(&port->tx_fifo);
786                 if (len) {
787                         unsigned long delay = (n == -ENOMEM) ? HZ : 1;
788                         schedule_delayed_work(&port->drain, delay);
789                 }
790                 len = dma_fifo_level(&port->tx_fifo);
791                 spin_unlock_bh(&port->lock);
792 
793                 /* wakeup the writer */
794                 if (drain && len < WAKEUP_CHARS)
795                         tty_wakeup(tty);
796         }
797 
798         clear_bit(IN_TX, &port->flags);
799         wake_up_interruptible(&port->wait_tx);
800 
801 out:
802         rcu_read_unlock();
803         tty_kref_put(tty);
804         return n;
805 }
806 
807 static void fwtty_drain_tx(struct work_struct *work)
808 {
809         struct fwtty_port *port = to_port(to_delayed_work(work), drain);
810 
811         fwtty_tx(port, true);
812 }
813 
814 static void fwtty_write_xchar(struct fwtty_port *port, char ch)
815 {
816         struct fwtty_peer *peer;
817 
818         ++port->stats.xchars;
819 
820         fwtty_dbg(port, "%02x\n", ch);
821 
822         rcu_read_lock();
823         peer = rcu_dereference(port->peer);
824         if (peer) {
825                 fwtty_send_data_async(peer, TCODE_WRITE_BLOCK_REQUEST,
826                                       peer->fifo_addr, &ch, sizeof(ch),
827                                       NULL, port);
828         }
829         rcu_read_unlock();
830 }
831 
832 struct fwtty_port *fwtty_port_get(unsigned index)
833 {
834         struct fwtty_port *port;
835 
836         if (index >= MAX_TOTAL_PORTS)
837                 return NULL;
838 
839         mutex_lock(&port_table_lock);
840         port = port_table[index];
841         if (port)
842                 kref_get(&port->serial->kref);
843         mutex_unlock(&port_table_lock);
844         return port;
845 }
846 EXPORT_SYMBOL(fwtty_port_get);
847 
848 static int fwtty_ports_add(struct fw_serial *serial)
849 {
850         int err = -EBUSY;
851         int i, j;
852 
853         if (port_table_corrupt)
854                 return err;
855 
856         mutex_lock(&port_table_lock);
857         for (i = 0; i + num_ports <= MAX_TOTAL_PORTS; i += num_ports) {
858                 if (!port_table[i]) {
859                         for (j = 0; j < num_ports; ++i, ++j) {
860                                 serial->ports[j]->index = i;
861                                 port_table[i] = serial->ports[j];
862                         }
863                         err = 0;
864                         break;
865                 }
866         }
867         mutex_unlock(&port_table_lock);
868         return err;
869 }
870 
871 static void fwserial_destroy(struct kref *kref)
872 {
873         struct fw_serial *serial = to_serial(kref, kref);
874         struct fwtty_port **ports = serial->ports;
875         int j, i = ports[0]->index;
876 
877         synchronize_rcu();
878 
879         mutex_lock(&port_table_lock);
880         for (j = 0; j < num_ports; ++i, ++j) {
881                 port_table_corrupt |= port_table[i] != ports[j];
882                 WARN_ONCE(port_table_corrupt, "port_table[%d]: %p != ports[%d]: %p",
883                           i, port_table[i], j, ports[j]);
884 
885                 port_table[i] = NULL;
886         }
887         mutex_unlock(&port_table_lock);
888 
889         for (j = 0; j < num_ports; ++j) {
890                 fw_core_remove_address_handler(&ports[j]->rx_handler);
891                 tty_port_destroy(&ports[j]->port);
892                 kfree(ports[j]);
893         }
894         kfree(serial);
895 }
896 
897 void fwtty_port_put(struct fwtty_port *port)
898 {
899         kref_put(&port->serial->kref, fwserial_destroy);
900 }
901 EXPORT_SYMBOL(fwtty_port_put);
902 
903 static void fwtty_port_dtr_rts(struct tty_port *tty_port, int on)
904 {
905         struct fwtty_port *port = to_port(tty_port, port);
906 
907         fwtty_dbg(port, "on/off: %d\n", on);
908 
909         spin_lock_bh(&port->lock);
910         /* Don't change carrier state if this is a console */
911         if (!port->port.console) {
912                 if (on)
913                         port->mctrl |= TIOCM_DTR | TIOCM_RTS;
914                 else
915                         port->mctrl &= ~(TIOCM_DTR | TIOCM_RTS);
916         }
917 
918         __fwtty_write_port_status(port);
919         spin_unlock_bh(&port->lock);
920 }
921 
922 /**
923  * fwtty_port_carrier_raised: required tty_port operation
924  *
925  * This port operation is polled after a tty has been opened and is waiting for
926  * carrier detect -- see drivers/tty/tty_port:tty_port_block_til_ready().
927  */
928 static int fwtty_port_carrier_raised(struct tty_port *tty_port)
929 {
930         struct fwtty_port *port = to_port(tty_port, port);
931         int rc;
932 
933         rc = (port->mstatus & TIOCM_CAR);
934 
935         fwtty_dbg(port, "%d\n", rc);
936 
937         return rc;
938 }
939 
940 static unsigned set_termios(struct fwtty_port *port, struct tty_struct *tty)
941 {
942         unsigned baud, frame;
943 
944         baud = tty_termios_baud_rate(&tty->termios);
945         tty_termios_encode_baud_rate(&tty->termios, baud, baud);
946 
947         /* compute bit count of 2 frames */
948         frame = 12 + ((C_CSTOPB(tty)) ? 4 : 2) + ((C_PARENB(tty)) ? 2 : 0);
949 
950         switch (C_CSIZE(tty)) {
951         case CS5:
952                 frame -= (C_CSTOPB(tty)) ? 1 : 0;
953                 break;
954         case CS6:
955                 frame += 2;
956                 break;
957         case CS7:
958                 frame += 4;
959                 break;
960         case CS8:
961                 frame += 6;
962                 break;
963         }
964 
965         port->cps = (baud << 1) / frame;
966 
967         port->status_mask = UART_LSR_OE;
968         if (_I_FLAG(tty, BRKINT | PARMRK))
969                 port->status_mask |= UART_LSR_BI;
970 
971         port->ignore_mask = 0;
972         if (I_IGNBRK(tty)) {
973                 port->ignore_mask |= UART_LSR_BI;
974                 if (I_IGNPAR(tty))
975                         port->ignore_mask |= UART_LSR_OE;
976         }
977 
978         port->write_only = !C_CREAD(tty);
979 
980         /* turn off echo and newline xlat if loopback */
981         if (port->loopback) {
982                 tty->termios.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHOKE |
983                                           ECHONL | ECHOPRT | ECHOCTL);
984                 tty->termios.c_oflag &= ~ONLCR;
985         }
986 
987         return baud;
988 }
989 
990 static int fwtty_port_activate(struct tty_port *tty_port,
991                                struct tty_struct *tty)
992 {
993         struct fwtty_port *port = to_port(tty_port, port);
994         unsigned baud;
995         int err;
996 
997         set_bit(TTY_IO_ERROR, &tty->flags);
998 
999         err = dma_fifo_alloc(&port->tx_fifo, FWTTY_PORT_TXFIFO_LEN,
1000                              cache_line_size(),
1001                              port->max_payload,
1002                              FWTTY_PORT_MAX_PEND_DMA,
1003                              GFP_KERNEL);
1004         if (err)
1005                 return err;
1006 
1007         spin_lock_bh(&port->lock);
1008 
1009         baud = set_termios(port, tty);
1010 
1011         /* if console, don't change carrier state */
1012         if (!port->port.console) {
1013                 port->mctrl = 0;
1014                 if (baud != 0)
1015                         port->mctrl = TIOCM_DTR | TIOCM_RTS;
1016         }
1017 
1018         if (C_CRTSCTS(tty) && ~port->mstatus & TIOCM_CTS)
1019                 tty->hw_stopped = 1;
1020 
1021         __fwtty_write_port_status(port);
1022         spin_unlock_bh(&port->lock);
1023 
1024         clear_bit(TTY_IO_ERROR, &tty->flags);
1025 
1026         return 0;
1027 }
1028 
1029 /**
1030  * fwtty_port_shutdown
1031  *
1032  * Note: the tty port core ensures this is not the console and
1033  * manages TTY_IO_ERROR properly
1034  */
1035 static void fwtty_port_shutdown(struct tty_port *tty_port)
1036 {
1037         struct fwtty_port *port = to_port(tty_port, port);
1038 
1039         /* TODO: cancel outstanding transactions */
1040 
1041         cancel_delayed_work_sync(&port->emit_breaks);
1042         cancel_delayed_work_sync(&port->drain);
1043 
1044         spin_lock_bh(&port->lock);
1045         port->flags = 0;
1046         port->break_ctl = 0;
1047         port->overrun = 0;
1048         __fwtty_write_port_status(port);
1049         dma_fifo_free(&port->tx_fifo);
1050         spin_unlock_bh(&port->lock);
1051 }
1052 
1053 static int fwtty_open(struct tty_struct *tty, struct file *fp)
1054 {
1055         struct fwtty_port *port = tty->driver_data;
1056 
1057         return tty_port_open(&port->port, tty, fp);
1058 }
1059 
1060 static void fwtty_close(struct tty_struct *tty, struct file *fp)
1061 {
1062         struct fwtty_port *port = tty->driver_data;
1063 
1064         tty_port_close(&port->port, tty, fp);
1065 }
1066 
1067 static void fwtty_hangup(struct tty_struct *tty)
1068 {
1069         struct fwtty_port *port = tty->driver_data;
1070 
1071         tty_port_hangup(&port->port);
1072 }
1073 
1074 static void fwtty_cleanup(struct tty_struct *tty)
1075 {
1076         struct fwtty_port *port = tty->driver_data;
1077 
1078         tty->driver_data = NULL;
1079         fwtty_port_put(port);
1080 }
1081 
1082 static int fwtty_install(struct tty_driver *driver, struct tty_struct *tty)
1083 {
1084         struct fwtty_port *port = fwtty_port_get(tty->index);
1085         int err;
1086 
1087         err = tty_standard_install(driver, tty);
1088         if (!err)
1089                 tty->driver_data = port;
1090         else
1091                 fwtty_port_put(port);
1092         return err;
1093 }
1094 
1095 static int fwloop_install(struct tty_driver *driver, struct tty_struct *tty)
1096 {
1097         struct fwtty_port *port = fwtty_port_get(table_idx(tty->index));
1098         int err;
1099 
1100         err = tty_standard_install(driver, tty);
1101         if (!err)
1102                 tty->driver_data = port;
1103         else
1104                 fwtty_port_put(port);
1105         return err;
1106 }
1107 
1108 static int fwtty_write(struct tty_struct *tty, const unsigned char *buf, int c)
1109 {
1110         struct fwtty_port *port = tty->driver_data;
1111         int n, len;
1112 
1113         fwtty_dbg(port, "%d\n", c);
1114         fwtty_profile_data(port->stats.writes, c);
1115 
1116         spin_lock_bh(&port->lock);
1117         n = dma_fifo_in(&port->tx_fifo, buf, c);
1118         len = dma_fifo_out_level(&port->tx_fifo);
1119         if (len < DRAIN_THRESHOLD)
1120                 schedule_delayed_work(&port->drain, 1);
1121         spin_unlock_bh(&port->lock);
1122 
1123         if (len >= DRAIN_THRESHOLD)
1124                 fwtty_tx(port, false);
1125 
1126         debug_short_write(port, c, n);
1127 
1128         return (n < 0) ? 0 : n;
1129 }
1130 
1131 static int fwtty_write_room(struct tty_struct *tty)
1132 {
1133         struct fwtty_port *port = tty->driver_data;
1134         int n;
1135 
1136         spin_lock_bh(&port->lock);
1137         n = dma_fifo_avail(&port->tx_fifo);
1138         spin_unlock_bh(&port->lock);
1139 
1140         fwtty_dbg(port, "%d\n", n);
1141 
1142         return n;
1143 }
1144 
1145 static int fwtty_chars_in_buffer(struct tty_struct *tty)
1146 {
1147         struct fwtty_port *port = tty->driver_data;
1148         int n;
1149 
1150         spin_lock_bh(&port->lock);
1151         n = dma_fifo_level(&port->tx_fifo);
1152         spin_unlock_bh(&port->lock);
1153 
1154         fwtty_dbg(port, "%d\n", n);
1155 
1156         return n;
1157 }
1158 
1159 static void fwtty_send_xchar(struct tty_struct *tty, char ch)
1160 {
1161         struct fwtty_port *port = tty->driver_data;
1162 
1163         fwtty_dbg(port, "%02x\n", ch);
1164 
1165         fwtty_write_xchar(port, ch);
1166 }
1167 
1168 static void fwtty_throttle(struct tty_struct *tty)
1169 {
1170         struct fwtty_port *port = tty->driver_data;
1171 
1172         /*
1173          * Ignore throttling (but not unthrottling).
1174          * It only makes sense to throttle when data will no longer be
1175          * accepted by the tty flip buffer. For example, it is
1176          * possible for received data to overflow the tty buffer long
1177          * before the line discipline ever has a chance to throttle the driver.
1178          * Additionally, the driver may have already completed the I/O
1179          * but the tty buffer is still emptying, so the line discipline is
1180          * throttling and unthrottling nothing.
1181          */
1182 
1183         ++port->stats.throttled;
1184 }
1185 
1186 static void fwtty_unthrottle(struct tty_struct *tty)
1187 {
1188         struct fwtty_port *port = tty->driver_data;
1189 
1190         fwtty_dbg(port, "CRTSCTS: %d\n", (C_CRTSCTS(tty) != 0));
1191 
1192         fwtty_profile_fifo(port, port->stats.unthrottle);
1193 
1194         spin_lock_bh(&port->lock);
1195         port->mctrl &= ~OOB_RX_THROTTLE;
1196         if (C_CRTSCTS(tty))
1197                 port->mctrl |= TIOCM_RTS;
1198         __fwtty_write_port_status(port);
1199         spin_unlock_bh(&port->lock);
1200 }
1201 
1202 static int check_msr_delta(struct fwtty_port *port, unsigned long mask,
1203                            struct async_icount *prev)
1204 {
1205         struct async_icount now;
1206         int delta;
1207 
1208         now = port->icount;
1209 
1210         delta = ((mask & TIOCM_RNG && prev->rng != now.rng) ||
1211                  (mask & TIOCM_DSR && prev->dsr != now.dsr) ||
1212                  (mask & TIOCM_CAR && prev->dcd != now.dcd) ||
1213                  (mask & TIOCM_CTS && prev->cts != now.cts));
1214 
1215         *prev = now;
1216 
1217         return delta;
1218 }
1219 
1220 static int wait_msr_change(struct fwtty_port *port, unsigned long mask)
1221 {
1222         struct async_icount prev;
1223 
1224         prev = port->icount;
1225 
1226         return wait_event_interruptible(port->port.delta_msr_wait,
1227                                         check_msr_delta(port, mask, &prev));
1228 }
1229 
1230 static int get_serial_info(struct fwtty_port *port,
1231                            struct serial_struct __user *info)
1232 {
1233         struct serial_struct tmp;
1234 
1235         memset(&tmp, 0, sizeof(tmp));
1236 
1237         tmp.type =  PORT_UNKNOWN;
1238         tmp.line =  port->port.tty->index;
1239         tmp.flags = port->port.flags;
1240         tmp.xmit_fifo_size = FWTTY_PORT_TXFIFO_LEN;
1241         tmp.baud_base = 400000000;
1242         tmp.close_delay = port->port.close_delay;
1243 
1244         return (copy_to_user(info, &tmp, sizeof(*info))) ? -EFAULT : 0;
1245 }
1246 
1247 static int set_serial_info(struct fwtty_port *port,
1248                            struct serial_struct __user *info)
1249 {
1250         struct serial_struct tmp;
1251 
1252         if (copy_from_user(&tmp, info, sizeof(tmp)))
1253                 return -EFAULT;
1254 
1255         if (tmp.irq != 0 || tmp.port != 0 || tmp.custom_divisor != 0 ||
1256             tmp.baud_base != 400000000)
1257                 return -EPERM;
1258 
1259         if (!capable(CAP_SYS_ADMIN)) {
1260                 if (((tmp.flags & ~ASYNC_USR_MASK) !=
1261                      (port->port.flags & ~ASYNC_USR_MASK)))
1262                         return -EPERM;
1263         } else {
1264                 port->port.close_delay = tmp.close_delay * HZ / 100;
1265         }
1266 
1267         return 0;
1268 }
1269 
1270 static int fwtty_ioctl(struct tty_struct *tty, unsigned cmd,
1271                        unsigned long arg)
1272 {
1273         struct fwtty_port *port = tty->driver_data;
1274         int err;
1275 
1276         switch (cmd) {
1277         case TIOCGSERIAL:
1278                 mutex_lock(&port->port.mutex);
1279                 err = get_serial_info(port, (void __user *)arg);
1280                 mutex_unlock(&port->port.mutex);
1281                 break;
1282 
1283         case TIOCSSERIAL:
1284                 mutex_lock(&port->port.mutex);
1285                 err = set_serial_info(port, (void __user *)arg);
1286                 mutex_unlock(&port->port.mutex);
1287                 break;
1288 
1289         case TIOCMIWAIT:
1290                 err = wait_msr_change(port, arg);
1291                 break;
1292 
1293         default:
1294                 err = -ENOIOCTLCMD;
1295         }
1296 
1297         return err;
1298 }
1299 
1300 static void fwtty_set_termios(struct tty_struct *tty, struct ktermios *old)
1301 {
1302         struct fwtty_port *port = tty->driver_data;
1303         unsigned baud;
1304 
1305         spin_lock_bh(&port->lock);
1306         baud = set_termios(port, tty);
1307 
1308         if ((baud == 0) && (old->c_cflag & CBAUD)) {
1309                 port->mctrl &= ~(TIOCM_DTR | TIOCM_RTS);
1310         } else if ((baud != 0) && !(old->c_cflag & CBAUD)) {
1311                 if (C_CRTSCTS(tty) || !test_bit(TTY_THROTTLED, &tty->flags))
1312                         port->mctrl |= TIOCM_DTR | TIOCM_RTS;
1313                 else
1314                         port->mctrl |= TIOCM_DTR;
1315         }
1316         __fwtty_write_port_status(port);
1317         spin_unlock_bh(&port->lock);
1318 
1319         if (old->c_cflag & CRTSCTS) {
1320                 if (!C_CRTSCTS(tty)) {
1321                         tty->hw_stopped = 0;
1322                         fwtty_restart_tx(port);
1323                 }
1324         } else if (C_CRTSCTS(tty) && ~port->mstatus & TIOCM_CTS) {
1325                 tty->hw_stopped = 1;
1326         }
1327 }
1328 
1329 /**
1330  * fwtty_break_ctl - start/stop sending breaks
1331  *
1332  * Signals the remote to start or stop generating simulated breaks.
1333  * First, stop dequeueing from the fifo and wait for writer/drain to leave tx
1334  * before signalling the break line status. This guarantees any pending rx will
1335  * be queued to the line discipline before break is simulated on the remote.
1336  * Conversely, turning off break_ctl requires signalling the line status change,
1337  * then enabling tx.
1338  */
1339 static int fwtty_break_ctl(struct tty_struct *tty, int state)
1340 {
1341         struct fwtty_port *port = tty->driver_data;
1342         long ret;
1343 
1344         fwtty_dbg(port, "%d\n", state);
1345 
1346         if (state == -1) {
1347                 set_bit(STOP_TX, &port->flags);
1348                 ret = wait_event_interruptible_timeout(port->wait_tx,
1349                                                !test_bit(IN_TX, &port->flags),
1350                                                10);
1351                 if (ret == 0 || ret == -ERESTARTSYS) {
1352                         clear_bit(STOP_TX, &port->flags);
1353                         fwtty_restart_tx(port);
1354                         return -EINTR;
1355                 }
1356         }
1357 
1358         spin_lock_bh(&port->lock);
1359         port->break_ctl = (state == -1);
1360         __fwtty_write_port_status(port);
1361         spin_unlock_bh(&port->lock);
1362 
1363         if (state == 0) {
1364                 spin_lock_bh(&port->lock);
1365                 dma_fifo_reset(&port->tx_fifo);
1366                 clear_bit(STOP_TX, &port->flags);
1367                 spin_unlock_bh(&port->lock);
1368         }
1369         return 0;
1370 }
1371 
1372 static int fwtty_tiocmget(struct tty_struct *tty)
1373 {
1374         struct fwtty_port *port = tty->driver_data;
1375         unsigned tiocm;
1376 
1377         spin_lock_bh(&port->lock);
1378         tiocm = (port->mctrl & MCTRL_MASK) | (port->mstatus & ~MCTRL_MASK);
1379         spin_unlock_bh(&port->lock);
1380 
1381         fwtty_dbg(port, "%x\n", tiocm);
1382 
1383         return tiocm;
1384 }
1385 
1386 static int fwtty_tiocmset(struct tty_struct *tty, unsigned set, unsigned clear)
1387 {
1388         struct fwtty_port *port = tty->driver_data;
1389 
1390         fwtty_dbg(port, "set: %x clear: %x\n", set, clear);
1391 
1392         /* TODO: simulate loopback if TIOCM_LOOP set */
1393 
1394         spin_lock_bh(&port->lock);
1395         port->mctrl &= ~(clear & MCTRL_MASK & 0xffff);
1396         port->mctrl |= set & MCTRL_MASK & 0xffff;
1397         __fwtty_write_port_status(port);
1398         spin_unlock_bh(&port->lock);
1399         return 0;
1400 }
1401 
1402 static int fwtty_get_icount(struct tty_struct *tty,
1403                             struct serial_icounter_struct *icount)
1404 {
1405         struct fwtty_port *port = tty->driver_data;
1406         struct stats stats;
1407 
1408         memcpy(&stats, &port->stats, sizeof(stats));
1409         if (port->port.console)
1410                 (*port->fwcon_ops->stats)(&stats, port->con_data);
1411 
1412         icount->cts = port->icount.cts;
1413         icount->dsr = port->icount.dsr;
1414         icount->rng = port->icount.rng;
1415         icount->dcd = port->icount.dcd;
1416         icount->rx  = port->icount.rx;
1417         icount->tx  = port->icount.tx + stats.xchars;
1418         icount->frame   = port->icount.frame;
1419         icount->overrun = port->icount.overrun;
1420         icount->parity  = port->icount.parity;
1421         icount->brk     = port->icount.brk;
1422         icount->buf_overrun = port->icount.overrun;
1423         return 0;
1424 }
1425 
1426 static void fwtty_proc_show_port(struct seq_file *m, struct fwtty_port *port)
1427 {
1428         struct stats stats;
1429 
1430         memcpy(&stats, &port->stats, sizeof(stats));
1431         if (port->port.console)
1432                 (*port->fwcon_ops->stats)(&stats, port->con_data);
1433 
1434         seq_printf(m, " addr:%012llx tx:%d rx:%d", port->rx_handler.offset,
1435                    port->icount.tx + stats.xchars, port->icount.rx);
1436         seq_printf(m, " cts:%d dsr:%d rng:%d dcd:%d", port->icount.cts,
1437                    port->icount.dsr, port->icount.rng, port->icount.dcd);
1438         seq_printf(m, " fe:%d oe:%d pe:%d brk:%d", port->icount.frame,
1439                    port->icount.overrun, port->icount.parity, port->icount.brk);
1440 }
1441 
1442 static void fwtty_debugfs_show_port(struct seq_file *m, struct fwtty_port *port)
1443 {
1444         struct stats stats;
1445 
1446         memcpy(&stats, &port->stats, sizeof(stats));
1447         if (port->port.console)
1448                 (*port->fwcon_ops->stats)(&stats, port->con_data);
1449 
1450         seq_printf(m, " dr:%d st:%d err:%d lost:%d", stats.dropped,
1451                    stats.tx_stall, stats.fifo_errs, stats.lost);
1452         seq_printf(m, " pkts:%d thr:%d", stats.sent, stats.throttled);
1453 
1454         if (port->port.console) {
1455                 seq_puts(m, "\n    ");
1456                 (*port->fwcon_ops->proc_show)(m, port->con_data);
1457         }
1458 
1459         fwtty_dump_profile(m, &port->stats);
1460 }
1461 
1462 static void fwtty_debugfs_show_peer(struct seq_file *m, struct fwtty_peer *peer)
1463 {
1464         int generation = peer->generation;
1465 
1466         smp_rmb();
1467         seq_printf(m, " %s:", dev_name(&peer->unit->device));
1468         seq_printf(m, " node:%04x gen:%d", peer->node_id, generation);
1469         seq_printf(m, " sp:%d max:%d guid:%016llx", peer->speed,
1470                    peer->max_payload, (unsigned long long) peer->guid);
1471         seq_printf(m, " mgmt:%012llx", (unsigned long long) peer->mgmt_addr);
1472         seq_printf(m, " addr:%012llx", (unsigned long long) peer->status_addr);
1473         seq_putc(m, '\n');
1474 }
1475 
1476 static int fwtty_proc_show(struct seq_file *m, void *v)
1477 {
1478         struct fwtty_port *port;
1479         int i;
1480 
1481         seq_puts(m, "fwserinfo: 1.0 driver: 1.0\n");
1482         for (i = 0; i < MAX_TOTAL_PORTS && (port = fwtty_port_get(i)); ++i) {
1483                 seq_printf(m, "%2d:", i);
1484                 if (capable(CAP_SYS_ADMIN))
1485                         fwtty_proc_show_port(m, port);
1486                 fwtty_port_put(port);
1487                 seq_puts(m, "\n");
1488         }
1489         return 0;
1490 }
1491 
1492 static int fwtty_debugfs_stats_show(struct seq_file *m, void *v)
1493 {
1494         struct fw_serial *serial = m->private;
1495         struct fwtty_port *port;
1496         int i;
1497 
1498         for (i = 0; i < num_ports; ++i) {
1499                 port = fwtty_port_get(serial->ports[i]->index);
1500                 if (port) {
1501                         seq_printf(m, "%2d:", port->index);
1502                         fwtty_proc_show_port(m, port);
1503                         fwtty_debugfs_show_port(m, port);
1504                         fwtty_port_put(port);
1505                         seq_puts(m, "\n");
1506                 }
1507         }
1508         return 0;
1509 }
1510 
1511 static int fwtty_debugfs_peers_show(struct seq_file *m, void *v)
1512 {
1513         struct fw_serial *serial = m->private;
1514         struct fwtty_peer *peer;
1515 
1516         rcu_read_lock();
1517         seq_printf(m, "card: %s  guid: %016llx\n",
1518                    dev_name(serial->card->device),
1519                    (unsigned long long) serial->card->guid);
1520         list_for_each_entry_rcu(peer, &serial->peer_list, list)
1521                 fwtty_debugfs_show_peer(m, peer);
1522         rcu_read_unlock();
1523         return 0;
1524 }
1525 
1526 static int fwtty_proc_open(struct inode *inode, struct file *fp)
1527 {
1528         return single_open(fp, fwtty_proc_show, NULL);
1529 }
1530 
1531 static int fwtty_stats_open(struct inode *inode, struct file *fp)
1532 {
1533         return single_open(fp, fwtty_debugfs_stats_show, inode->i_private);
1534 }
1535 
1536 static int fwtty_peers_open(struct inode *inode, struct file *fp)
1537 {
1538         return single_open(fp, fwtty_debugfs_peers_show, inode->i_private);
1539 }
1540 
1541 static const struct file_operations fwtty_stats_fops = {
1542         .owner =        THIS_MODULE,
1543         .open =         fwtty_stats_open,
1544         .read =         seq_read,
1545         .llseek =       seq_lseek,
1546         .release =      single_release,
1547 };
1548 
1549 static const struct file_operations fwtty_peers_fops = {
1550         .owner =        THIS_MODULE,
1551         .open =         fwtty_peers_open,
1552         .read =         seq_read,
1553         .llseek =       seq_lseek,
1554         .release =      single_release,
1555 };
1556 
1557 static const struct file_operations fwtty_proc_fops = {
1558         .owner =        THIS_MODULE,
1559         .open =         fwtty_proc_open,
1560         .read =         seq_read,
1561         .llseek =       seq_lseek,
1562         .release =      single_release,
1563 };
1564 
1565 static const struct tty_port_operations fwtty_port_ops = {
1566         .dtr_rts =              fwtty_port_dtr_rts,
1567         .carrier_raised =       fwtty_port_carrier_raised,
1568         .shutdown =             fwtty_port_shutdown,
1569         .activate =             fwtty_port_activate,
1570 };
1571 
1572 static const struct tty_operations fwtty_ops = {
1573         .open =                 fwtty_open,
1574         .close =                fwtty_close,
1575         .hangup =               fwtty_hangup,
1576         .cleanup =              fwtty_cleanup,
1577         .install =              fwtty_install,
1578         .write =                fwtty_write,
1579         .write_room =           fwtty_write_room,
1580         .chars_in_buffer =      fwtty_chars_in_buffer,
1581         .send_xchar =           fwtty_send_xchar,
1582         .throttle =             fwtty_throttle,
1583         .unthrottle =           fwtty_unthrottle,
1584         .ioctl =                fwtty_ioctl,
1585         .set_termios =          fwtty_set_termios,
1586         .break_ctl =            fwtty_break_ctl,
1587         .tiocmget =             fwtty_tiocmget,
1588         .tiocmset =             fwtty_tiocmset,
1589         .get_icount =           fwtty_get_icount,
1590         .proc_fops =            &fwtty_proc_fops,
1591 };
1592 
1593 static const struct tty_operations fwloop_ops = {
1594         .open =                 fwtty_open,
1595         .close =                fwtty_close,
1596         .hangup =               fwtty_hangup,
1597         .cleanup =              fwtty_cleanup,
1598         .install =              fwloop_install,
1599         .write =                fwtty_write,
1600         .write_room =           fwtty_write_room,
1601         .chars_in_buffer =      fwtty_chars_in_buffer,
1602         .send_xchar =           fwtty_send_xchar,
1603         .throttle =             fwtty_throttle,
1604         .unthrottle =           fwtty_unthrottle,
1605         .ioctl =                fwtty_ioctl,
1606         .set_termios =          fwtty_set_termios,
1607         .break_ctl =            fwtty_break_ctl,
1608         .tiocmget =             fwtty_tiocmget,
1609         .tiocmset =             fwtty_tiocmset,
1610         .get_icount =           fwtty_get_icount,
1611 };
1612 
1613 static inline int mgmt_pkt_expected_len(__be16 code)
1614 {
1615         static const struct fwserial_mgmt_pkt pkt;
1616 
1617         switch (be16_to_cpu(code)) {
1618         case FWSC_VIRT_CABLE_PLUG:
1619                 return sizeof(pkt.hdr) + sizeof(pkt.plug_req);
1620 
1621         case FWSC_VIRT_CABLE_PLUG_RSP:  /* | FWSC_RSP_OK */
1622                 return sizeof(pkt.hdr) + sizeof(pkt.plug_rsp);
1623 
1624 
1625         case FWSC_VIRT_CABLE_UNPLUG:
1626         case FWSC_VIRT_CABLE_UNPLUG_RSP:
1627         case FWSC_VIRT_CABLE_PLUG_RSP | FWSC_RSP_NACK:
1628         case FWSC_VIRT_CABLE_UNPLUG_RSP | FWSC_RSP_NACK:
1629                 return sizeof(pkt.hdr);
1630 
1631         default:
1632                 return -1;
1633         }
1634 }
1635 
1636 static inline void fill_plug_params(struct virt_plug_params *params,
1637                                     struct fwtty_port *port)
1638 {
1639         u64 status_addr = port->rx_handler.offset;
1640         u64 fifo_addr = port->rx_handler.offset + 4;
1641         size_t fifo_len = port->rx_handler.length - 4;
1642 
1643         params->status_hi = cpu_to_be32(status_addr >> 32);
1644         params->status_lo = cpu_to_be32(status_addr);
1645         params->fifo_hi = cpu_to_be32(fifo_addr >> 32);
1646         params->fifo_lo = cpu_to_be32(fifo_addr);
1647         params->fifo_len = cpu_to_be32(fifo_len);
1648 }
1649 
1650 static inline void fill_plug_req(struct fwserial_mgmt_pkt *pkt,
1651                                  struct fwtty_port *port)
1652 {
1653         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_PLUG);
1654         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1655         fill_plug_params(&pkt->plug_req, port);
1656 }
1657 
1658 static inline void fill_plug_rsp_ok(struct fwserial_mgmt_pkt *pkt,
1659                                     struct fwtty_port *port)
1660 {
1661         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_PLUG_RSP);
1662         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1663         fill_plug_params(&pkt->plug_rsp, port);
1664 }
1665 
1666 static inline void fill_plug_rsp_nack(struct fwserial_mgmt_pkt *pkt)
1667 {
1668         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_PLUG_RSP | FWSC_RSP_NACK);
1669         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1670 }
1671 
1672 static inline void fill_unplug_req(struct fwserial_mgmt_pkt *pkt)
1673 {
1674         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_UNPLUG);
1675         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1676 }
1677 
1678 static inline void fill_unplug_rsp_nack(struct fwserial_mgmt_pkt *pkt)
1679 {
1680         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_UNPLUG_RSP | FWSC_RSP_NACK);
1681         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1682 }
1683 
1684 static inline void fill_unplug_rsp_ok(struct fwserial_mgmt_pkt *pkt)
1685 {
1686         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_UNPLUG_RSP);
1687         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1688 }
1689 
1690 static void fwserial_virt_plug_complete(struct fwtty_peer *peer,
1691                                         struct virt_plug_params *params)
1692 {
1693         struct fwtty_port *port = peer->port;
1694 
1695         peer->status_addr = be32_to_u64(params->status_hi, params->status_lo);
1696         peer->fifo_addr = be32_to_u64(params->fifo_hi, params->fifo_lo);
1697         peer->fifo_len = be32_to_cpu(params->fifo_len);
1698         peer_set_state(peer, FWPS_ATTACHED);
1699 
1700         /* reconfigure tx_fifo optimally for this peer */
1701         spin_lock_bh(&port->lock);
1702         port->max_payload = min(peer->max_payload, peer->fifo_len);
1703         dma_fifo_change_tx_limit(&port->tx_fifo, port->max_payload);
1704         spin_unlock_bh(&peer->port->lock);
1705 
1706         if (port->port.console && port->fwcon_ops->notify != NULL)
1707                 (*port->fwcon_ops->notify)(FWCON_NOTIFY_ATTACH, port->con_data);
1708 
1709         fwtty_info(&peer->unit, "peer (guid:%016llx) connected on %s\n",
1710                    (unsigned long long)peer->guid, dev_name(port->device));
1711 }
1712 
1713 static inline int fwserial_send_mgmt_sync(struct fwtty_peer *peer,
1714                                           struct fwserial_mgmt_pkt *pkt)
1715 {
1716         int generation;
1717         int rcode, tries = 5;
1718 
1719         do {
1720                 generation = peer->generation;
1721                 smp_rmb();
1722 
1723                 rcode = fw_run_transaction(peer->serial->card,
1724                                            TCODE_WRITE_BLOCK_REQUEST,
1725                                            peer->node_id,
1726                                            generation, peer->speed,
1727                                            peer->mgmt_addr,
1728                                            pkt, be16_to_cpu(pkt->hdr.len));
1729                 if (rcode == RCODE_BUSY || rcode == RCODE_SEND_ERROR ||
1730                     rcode == RCODE_GENERATION) {
1731                         fwtty_dbg(&peer->unit, "mgmt write error: %d\n", rcode);
1732                         continue;
1733                 } else {
1734                         break;
1735                 }
1736         } while (--tries > 0);
1737         return rcode;
1738 }
1739 
1740 /**
1741  * fwserial_claim_port - attempt to claim port @ index for peer
1742  *
1743  * Returns ptr to claimed port or error code (as ERR_PTR())
1744  * Can sleep - must be called from process context
1745  */
1746 static struct fwtty_port *fwserial_claim_port(struct fwtty_peer *peer,
1747                                               int index)
1748 {
1749         struct fwtty_port *port;
1750 
1751         if (index < 0 || index >= num_ports)
1752                 return ERR_PTR(-EINVAL);
1753 
1754         /* must guarantee that previous port releases have completed */
1755         synchronize_rcu();
1756 
1757         port = peer->serial->ports[index];
1758         spin_lock_bh(&port->lock);
1759         if (!rcu_access_pointer(port->peer))
1760                 rcu_assign_pointer(port->peer, peer);
1761         else
1762                 port = ERR_PTR(-EBUSY);
1763         spin_unlock_bh(&port->lock);
1764 
1765         return port;
1766 }
1767 
1768 /**
1769  * fwserial_find_port - find avail port and claim for peer
1770  *
1771  * Returns ptr to claimed port or NULL if none avail
1772  * Can sleep - must be called from process context
1773  */
1774 static struct fwtty_port *fwserial_find_port(struct fwtty_peer *peer)
1775 {
1776         struct fwtty_port **ports = peer->serial->ports;
1777         int i;
1778 
1779         /* must guarantee that previous port releases have completed */
1780         synchronize_rcu();
1781 
1782         /* TODO: implement optional GUID-to-specific port # matching */
1783 
1784         /* find an unattached port (but not the loopback port, if present) */
1785         for (i = 0; i < num_ttys; ++i) {
1786                 spin_lock_bh(&ports[i]->lock);
1787                 if (!ports[i]->peer) {
1788                         /* claim port */
1789                         rcu_assign_pointer(ports[i]->peer, peer);
1790                         spin_unlock_bh(&ports[i]->lock);
1791                         return ports[i];
1792                 }
1793                 spin_unlock_bh(&ports[i]->lock);
1794         }
1795         return NULL;
1796 }
1797 
1798 static void fwserial_release_port(struct fwtty_port *port, bool reset)
1799 {
1800         /* drop carrier (and all other line status) */
1801         if (reset)
1802                 fwtty_update_port_status(port, 0);
1803 
1804         spin_lock_bh(&port->lock);
1805 
1806         /* reset dma fifo max transmission size back to S100 */
1807         port->max_payload = link_speed_to_max_payload(SCODE_100);
1808         dma_fifo_change_tx_limit(&port->tx_fifo, port->max_payload);
1809 
1810         RCU_INIT_POINTER(port->peer, NULL);
1811         spin_unlock_bh(&port->lock);
1812 
1813         if (port->port.console && port->fwcon_ops->notify != NULL)
1814                 (*port->fwcon_ops->notify)(FWCON_NOTIFY_DETACH, port->con_data);
1815 }
1816 
1817 static void fwserial_plug_timeout(unsigned long data)
1818 {
1819         struct fwtty_peer *peer = (struct fwtty_peer *)data;
1820         struct fwtty_port *port;
1821 
1822         spin_lock_bh(&peer->lock);
1823         if (peer->state != FWPS_PLUG_PENDING) {
1824                 spin_unlock_bh(&peer->lock);
1825                 return;
1826         }
1827 
1828         port = peer_revert_state(peer);
1829         spin_unlock_bh(&peer->lock);
1830 
1831         if (port)
1832                 fwserial_release_port(port, false);
1833 }
1834 
1835 /**
1836  * fwserial_connect_peer - initiate virtual cable with peer
1837  *
1838  * Returns 0 if VIRT_CABLE_PLUG request was successfully sent,
1839  * otherwise error code.  Must be called from process context.
1840  */
1841 static int fwserial_connect_peer(struct fwtty_peer *peer)
1842 {
1843         struct fwtty_port *port;
1844         struct fwserial_mgmt_pkt *pkt;
1845         int err, rcode;
1846 
1847         pkt = kmalloc(sizeof(*pkt), GFP_KERNEL);
1848         if (!pkt)
1849                 return -ENOMEM;
1850 
1851         port = fwserial_find_port(peer);
1852         if (!port) {
1853                 fwtty_err(&peer->unit, "avail ports in use\n");
1854                 err = -EBUSY;
1855                 goto free_pkt;
1856         }
1857 
1858         spin_lock_bh(&peer->lock);
1859 
1860         /* only initiate VIRT_CABLE_PLUG if peer is currently not attached */
1861         if (peer->state != FWPS_NOT_ATTACHED) {
1862                 err = -EBUSY;
1863                 goto release_port;
1864         }
1865 
1866         peer->port = port;
1867         peer_set_state(peer, FWPS_PLUG_PENDING);
1868 
1869         fill_plug_req(pkt, peer->port);
1870 
1871         setup_timer(&peer->timer, fwserial_plug_timeout, (unsigned long)peer);
1872         mod_timer(&peer->timer, jiffies + VIRT_CABLE_PLUG_TIMEOUT);
1873         spin_unlock_bh(&peer->lock);
1874 
1875         rcode = fwserial_send_mgmt_sync(peer, pkt);
1876 
1877         spin_lock_bh(&peer->lock);
1878         if (peer->state == FWPS_PLUG_PENDING && rcode != RCODE_COMPLETE) {
1879                 if (rcode == RCODE_CONFLICT_ERROR)
1880                         err = -EAGAIN;
1881                 else
1882                         err = -EIO;
1883                 goto cancel_timer;
1884         }
1885         spin_unlock_bh(&peer->lock);
1886 
1887         kfree(pkt);
1888         return 0;
1889 
1890 cancel_timer:
1891         del_timer(&peer->timer);
1892         peer_revert_state(peer);
1893 release_port:
1894         spin_unlock_bh(&peer->lock);
1895         fwserial_release_port(port, false);
1896 free_pkt:
1897         kfree(pkt);
1898         return err;
1899 }
1900 
1901 /**
1902  * fwserial_close_port -
1903  * HUP the tty (if the tty exists) and unregister the tty device.
1904  * Only used by the unit driver upon unit removal to disconnect and
1905  * cleanup all attached ports
1906  *
1907  * The port reference is put by fwtty_cleanup (if a reference was
1908  * ever taken).
1909  */
1910 static void fwserial_close_port(struct tty_driver *driver,
1911                                 struct fwtty_port *port)
1912 {
1913         struct tty_struct *tty;
1914 
1915         mutex_lock(&port->port.mutex);
1916         tty = tty_port_tty_get(&port->port);
1917         if (tty) {
1918                 tty_vhangup(tty);
1919                 tty_kref_put(tty);
1920         }
1921         mutex_unlock(&port->port.mutex);
1922 
1923         if (driver == fwloop_driver)
1924                 tty_unregister_device(driver, loop_idx(port));
1925         else
1926                 tty_unregister_device(driver, port->index);
1927 }
1928 
1929 /**
1930  * fwserial_lookup - finds first fw_serial associated with card
1931  * @card: fw_card to match
1932  *
1933  * NB: caller must be holding fwserial_list_mutex
1934  */
1935 static struct fw_serial *fwserial_lookup(struct fw_card *card)
1936 {
1937         struct fw_serial *serial;
1938 
1939         list_for_each_entry(serial, &fwserial_list, list) {
1940                 if (card == serial->card)
1941                         return serial;
1942         }
1943 
1944         return NULL;
1945 }
1946 
1947 /**
1948  * __fwserial_lookup_rcu - finds first fw_serial associated with card
1949  * @card: fw_card to match
1950  *
1951  * NB: caller must be inside rcu_read_lock() section
1952  */
1953 static struct fw_serial *__fwserial_lookup_rcu(struct fw_card *card)
1954 {
1955         struct fw_serial *serial;
1956 
1957         list_for_each_entry_rcu(serial, &fwserial_list, list) {
1958                 if (card == serial->card)
1959                         return serial;
1960         }
1961 
1962         return NULL;
1963 }
1964 
1965 /**
1966  * __fwserial_peer_by_node_id - finds a peer matching the given generation + id
1967  *
1968  * If a matching peer could not be found for the specified generation/node id,
1969  * this could be because:
1970  * a) the generation has changed and one of the nodes hasn't updated yet
1971  * b) the remote node has created its remote unit device before this
1972  *    local node has created its corresponding remote unit device
1973  * In either case, the remote node should retry
1974  *
1975  * Note: caller must be in rcu_read_lock() section
1976  */
1977 static struct fwtty_peer *__fwserial_peer_by_node_id(struct fw_card *card,
1978                                                      int generation, int id)
1979 {
1980         struct fw_serial *serial;
1981         struct fwtty_peer *peer;
1982 
1983         serial = __fwserial_lookup_rcu(card);
1984         if (!serial) {
1985                 /*
1986                  * Something is very wrong - there should be a matching
1987                  * fw_serial structure for every fw_card. Maybe the remote node
1988                  * has created its remote unit device before this driver has
1989                  * been probed for any unit devices...
1990                  */
1991                 fwtty_err(card, "unknown card (guid %016llx)\n",
1992                           (unsigned long long) card->guid);
1993                 return NULL;
1994         }
1995 
1996         list_for_each_entry_rcu(peer, &serial->peer_list, list) {
1997                 int g = peer->generation;
1998                 smp_rmb();
1999                 if (generation == g && id == peer->node_id)
2000                         return peer;
2001         }
2002 
2003         return NULL;
2004 }
2005 
2006 #ifdef DEBUG
2007 static void __dump_peer_list(struct fw_card *card)
2008 {
2009         struct fw_serial *serial;
2010         struct fwtty_peer *peer;
2011 
2012         serial = __fwserial_lookup_rcu(card);
2013         if (!serial)
2014                 return;
2015 
2016         list_for_each_entry_rcu(peer, &serial->peer_list, list) {
2017                 int g = peer->generation;
2018                 smp_rmb();
2019                 fwtty_dbg(card, "peer(%d:%x) guid: %016llx\n",
2020                           g, peer->node_id, (unsigned long long) peer->guid);
2021         }
2022 }
2023 #else
2024 #define __dump_peer_list(s)
2025 #endif
2026 
2027 static void fwserial_auto_connect(struct work_struct *work)
2028 {
2029         struct fwtty_peer *peer = to_peer(to_delayed_work(work), connect);
2030         int err;
2031 
2032         err = fwserial_connect_peer(peer);
2033         if (err == -EAGAIN && ++peer->connect_retries < MAX_CONNECT_RETRIES)
2034                 schedule_delayed_work(&peer->connect, CONNECT_RETRY_DELAY);
2035 }
2036 
2037 static void fwserial_peer_workfn(struct work_struct *work)
2038 {
2039         struct fwtty_peer *peer = to_peer(work, work);
2040 
2041         peer->workfn(work);
2042 }
2043 
2044 /**
2045  * fwserial_add_peer - add a newly probed 'serial' unit device as a 'peer'
2046  * @serial: aggregate representing the specific fw_card to add the peer to
2047  * @unit: 'peer' to create and add to peer_list of serial
2048  *
2049  * Adds a 'peer' (ie, a local or remote 'serial' unit device) to the list of
2050  * peers for a specific fw_card. Optionally, auto-attach this peer to an
2051  * available tty port. This function is called either directly or indirectly
2052  * as a result of a 'serial' unit device being created & probed.
2053  *
2054  * Note: this function is serialized with fwserial_remove_peer() by the
2055  * fwserial_list_mutex held in fwserial_probe().
2056  *
2057  * A 1:1 correspondence between an fw_unit and an fwtty_peer is maintained
2058  * via the dev_set_drvdata() for the device of the fw_unit.
2059  */
2060 static int fwserial_add_peer(struct fw_serial *serial, struct fw_unit *unit)
2061 {
2062         struct device *dev = &unit->device;
2063         struct fw_device  *parent = fw_parent_device(unit);
2064         struct fwtty_peer *peer;
2065         struct fw_csr_iterator ci;
2066         int key, val;
2067         int generation;
2068 
2069         peer = kzalloc(sizeof(*peer), GFP_KERNEL);
2070         if (!peer)
2071                 return -ENOMEM;
2072 
2073         peer_set_state(peer, FWPS_NOT_ATTACHED);
2074 
2075         dev_set_drvdata(dev, peer);
2076         peer->unit = unit;
2077         peer->guid = (u64)parent->config_rom[3] << 32 | parent->config_rom[4];
2078         peer->speed = parent->max_speed;
2079         peer->max_payload = min(device_max_receive(parent),
2080                                 link_speed_to_max_payload(peer->speed));
2081 
2082         generation = parent->generation;
2083         smp_rmb();
2084         peer->node_id = parent->node_id;
2085         smp_wmb();
2086         peer->generation = generation;
2087 
2088         /* retrieve the mgmt bus addr from the unit directory */
2089         fw_csr_iterator_init(&ci, unit->directory);
2090         while (fw_csr_iterator_next(&ci, &key, &val)) {
2091                 if (key == (CSR_OFFSET | CSR_DEPENDENT_INFO)) {
2092                         peer->mgmt_addr = CSR_REGISTER_BASE + 4 * val;
2093                         break;
2094                 }
2095         }
2096         if (peer->mgmt_addr == 0ULL) {
2097                 /*
2098                  * No mgmt address effectively disables VIRT_CABLE_PLUG -
2099                  * this peer will not be able to attach to a remote
2100                  */
2101                 peer_set_state(peer, FWPS_NO_MGMT_ADDR);
2102         }
2103 
2104         spin_lock_init(&peer->lock);
2105         peer->port = NULL;
2106 
2107         init_timer(&peer->timer);
2108         INIT_WORK(&peer->work, fwserial_peer_workfn);
2109         INIT_DELAYED_WORK(&peer->connect, fwserial_auto_connect);
2110 
2111         /* associate peer with specific fw_card */
2112         peer->serial = serial;
2113         list_add_rcu(&peer->list, &serial->peer_list);
2114 
2115         fwtty_info(&peer->unit, "peer added (guid:%016llx)\n",
2116                    (unsigned long long)peer->guid);
2117 
2118         /* identify the local unit & virt cable to loopback port */
2119         if (parent->is_local) {
2120                 serial->self = peer;
2121                 if (create_loop_dev) {
2122                         struct fwtty_port *port;
2123                         port = fwserial_claim_port(peer, num_ttys);
2124                         if (!IS_ERR(port)) {
2125                                 struct virt_plug_params params;
2126 
2127                                 spin_lock_bh(&peer->lock);
2128                                 peer->port = port;
2129                                 fill_plug_params(&params, port);
2130                                 fwserial_virt_plug_complete(peer, &params);
2131                                 spin_unlock_bh(&peer->lock);
2132 
2133                                 fwtty_write_port_status(port);
2134                         }
2135                 }
2136 
2137         } else if (auto_connect) {
2138                 /* auto-attach to remote units only (if policy allows) */
2139                 schedule_delayed_work(&peer->connect, 1);
2140         }
2141 
2142         return 0;
2143 }
2144 
2145 /**
2146  * fwserial_remove_peer - remove a 'serial' unit device as a 'peer'
2147  *
2148  * Remove a 'peer' from its list of peers. This function is only
2149  * called by fwserial_remove() on bus removal of the unit device.
2150  *
2151  * Note: this function is serialized with fwserial_add_peer() by the
2152  * fwserial_list_mutex held in fwserial_remove().
2153  */
2154 static void fwserial_remove_peer(struct fwtty_peer *peer)
2155 {
2156         struct fwtty_port *port;
2157 
2158         spin_lock_bh(&peer->lock);
2159         peer_set_state(peer, FWPS_GONE);
2160         spin_unlock_bh(&peer->lock);
2161 
2162         cancel_delayed_work_sync(&peer->connect);
2163         cancel_work_sync(&peer->work);
2164 
2165         spin_lock_bh(&peer->lock);
2166         /* if this unit is the local unit, clear link */
2167         if (peer == peer->serial->self)
2168                 peer->serial->self = NULL;
2169 
2170         /* cancel the request timeout timer (if running) */
2171         del_timer(&peer->timer);
2172 
2173         port = peer->port;
2174         peer->port = NULL;
2175 
2176         list_del_rcu(&peer->list);
2177 
2178         fwtty_info(&peer->unit, "peer removed (guid:%016llx)\n",
2179                    (unsigned long long)peer->guid);
2180 
2181         spin_unlock_bh(&peer->lock);
2182 
2183         if (port)
2184                 fwserial_release_port(port, true);
2185 
2186         synchronize_rcu();
2187         kfree(peer);
2188 }
2189 
2190 /**
2191  * fwserial_create - init everything to create TTYs for a specific fw_card
2192  * @unit: fw_unit for first 'serial' unit device probed for this fw_card
2193  *
2194  * This function inits the aggregate structure (an fw_serial instance)
2195  * used to manage the TTY ports registered by a specific fw_card. Also, the
2196  * unit device is added as the first 'peer'.
2197  *
2198  * This unit device may represent a local unit device (as specified by the
2199  * config ROM unit directory) or it may represent a remote unit device
2200  * (as specified by the reading of the remote node's config ROM).
2201  *
2202  * Returns 0 to indicate "ownership" of the unit device, or a negative errno
2203  * value to indicate which error.
2204  */
2205 static int fwserial_create(struct fw_unit *unit)
2206 {
2207         struct fw_device *parent = fw_parent_device(unit);
2208         struct fw_card *card = parent->card;
2209         struct fw_serial *serial;
2210         struct fwtty_port *port;
2211         struct device *tty_dev;
2212         int i, j;
2213         int err;
2214 
2215         serial = kzalloc(sizeof(*serial), GFP_KERNEL);
2216         if (!serial)
2217                 return -ENOMEM;
2218 
2219         kref_init(&serial->kref);
2220         serial->card = card;
2221         INIT_LIST_HEAD(&serial->peer_list);
2222 
2223         for (i = 0; i < num_ports; ++i) {
2224                 port = kzalloc(sizeof(*port), GFP_KERNEL);
2225                 if (!port) {
2226                         err = -ENOMEM;
2227                         goto free_ports;
2228                 }
2229                 tty_port_init(&port->port);
2230                 port->index = FWTTY_INVALID_INDEX;
2231                 port->port.ops = &fwtty_port_ops;
2232                 port->serial = serial;
2233                 tty_buffer_set_limit(&port->port, 128 * 1024);
2234 
2235                 spin_lock_init(&port->lock);
2236                 INIT_DELAYED_WORK(&port->drain, fwtty_drain_tx);
2237                 INIT_DELAYED_WORK(&port->emit_breaks, fwtty_emit_breaks);
2238                 INIT_WORK(&port->hangup, fwtty_do_hangup);
2239                 init_waitqueue_head(&port->wait_tx);
2240                 port->max_payload = link_speed_to_max_payload(SCODE_100);
2241                 dma_fifo_init(&port->tx_fifo);
2242 
2243                 RCU_INIT_POINTER(port->peer, NULL);
2244                 serial->ports[i] = port;
2245 
2246                 /* get unique bus addr region for port's status & recv fifo */
2247                 port->rx_handler.length = FWTTY_PORT_RXFIFO_LEN + 4;
2248                 port->rx_handler.address_callback = fwtty_port_handler;
2249                 port->rx_handler.callback_data = port;
2250                 /*
2251                  * XXX: use custom memory region above cpu physical memory addrs
2252                  * this will ease porting to 64-bit firewire adapters
2253                  */
2254                 err = fw_core_add_address_handler(&port->rx_handler,
2255                                                   &fw_high_memory_region);
2256                 if (err) {
2257                         kfree(port);
2258                         goto free_ports;
2259                 }
2260         }
2261         /* preserve i for error cleanup */
2262 
2263         err = fwtty_ports_add(serial);
2264         if (err) {
2265                 fwtty_err(&unit, "no space in port table\n");
2266                 goto free_ports;
2267         }
2268 
2269         for (j = 0; j < num_ttys; ++j) {
2270                 tty_dev = tty_port_register_device(&serial->ports[j]->port,
2271                                                    fwtty_driver,
2272                                                    serial->ports[j]->index,
2273                                                    card->device);
2274                 if (IS_ERR(tty_dev)) {
2275                         err = PTR_ERR(tty_dev);
2276                         fwtty_err(&unit, "register tty device error (%d)\n",
2277                                   err);
2278                         goto unregister_ttys;
2279                 }
2280 
2281                 serial->ports[j]->device = tty_dev;
2282         }
2283         /* preserve j for error cleanup */
2284 
2285         if (create_loop_dev) {
2286                 struct device *loop_dev;
2287 
2288                 loop_dev = tty_port_register_device(&serial->ports[j]->port,
2289                                                     fwloop_driver,
2290                                                     loop_idx(serial->ports[j]),
2291                                                     card->device);
2292                 if (IS_ERR(loop_dev)) {
2293                         err = PTR_ERR(loop_dev);
2294                         fwtty_err(&unit, "create loop device failed (%d)\n",
2295                                   err);
2296                         goto unregister_ttys;
2297                 }
2298                 serial->ports[j]->device = loop_dev;
2299                 serial->ports[j]->loopback = true;
2300         }
2301 
2302         if (!IS_ERR_OR_NULL(fwserial_debugfs)) {
2303                 serial->debugfs = debugfs_create_dir(dev_name(&unit->device),
2304                                                      fwserial_debugfs);
2305                 if (!IS_ERR_OR_NULL(serial->debugfs)) {
2306                         debugfs_create_file("peers", 0444, serial->debugfs,
2307                                             serial, &fwtty_peers_fops);
2308                         debugfs_create_file("stats", 0444, serial->debugfs,
2309                                             serial, &fwtty_stats_fops);
2310                 }
2311         }
2312 
2313         list_add_rcu(&serial->list, &fwserial_list);
2314 
2315         fwtty_notice(&unit, "TTY over FireWire on device %s (guid %016llx)\n",
2316                      dev_name(card->device), (unsigned long long) card->guid);
2317 
2318         err = fwserial_add_peer(serial, unit);
2319         if (!err)
2320                 return 0;
2321 
2322         fwtty_err(&unit, "unable to add peer unit device (%d)\n", err);
2323 
2324         /* fall-through to error processing */
2325         debugfs_remove_recursive(serial->debugfs);
2326 
2327         list_del_rcu(&serial->list);
2328         if (create_loop_dev)
2329                 tty_unregister_device(fwloop_driver,
2330                                       loop_idx(serial->ports[j]));
2331 unregister_ttys:
2332         for (--j; j >= 0; --j)
2333                 tty_unregister_device(fwtty_driver, serial->ports[j]->index);
2334         kref_put(&serial->kref, fwserial_destroy);
2335         return err;
2336 
2337 free_ports:
2338         for (--i; i >= 0; --i) {
2339                 tty_port_destroy(&serial->ports[i]->port);
2340                 kfree(serial->ports[i]);
2341         }
2342         kfree(serial);
2343         return err;
2344 }
2345 
2346 /**
2347  * fwserial_probe: bus probe function for firewire 'serial' unit devices
2348  *
2349  * A 'serial' unit device is created and probed as a result of:
2350  * - declaring a ieee1394 bus id table for 'devices' matching a fabricated
2351  *   'serial' unit specifier id
2352  * - adding a unit directory to the config ROM(s) for a 'serial' unit
2353  *
2354  * The firewire core registers unit devices by enumerating unit directories
2355  * of a node's config ROM after reading the config ROM when a new node is
2356  * added to the bus topology after a bus reset.
2357  *
2358  * The practical implications of this are:
2359  * - this probe is called for both local and remote nodes that have a 'serial'
2360  *   unit directory in their config ROM (that matches the specifiers in
2361  *   fwserial_id_table).
2362  * - no specific order is enforced for local vs. remote unit devices
2363  *
2364  * This unit driver copes with the lack of specific order in the same way the
2365  * firewire net driver does -- each probe, for either a local or remote unit
2366  * device, is treated as a 'peer' (has a struct fwtty_peer instance) and the
2367  * first peer created for a given fw_card (tracked by the global fwserial_list)
2368  * creates the underlying TTYs (aggregated in a fw_serial instance).
2369  *
2370  * NB: an early attempt to differentiate local & remote unit devices by creating
2371  *     peers only for remote units and fw_serial instances (with their
2372  *     associated TTY devices) only for local units was discarded. Managing
2373  *     the peer lifetimes on device removal proved too complicated.
2374  *
2375  * fwserial_probe/fwserial_remove are effectively serialized by the
2376  * fwserial_list_mutex. This is necessary because the addition of the first peer
2377  * for a given fw_card will trigger the creation of the fw_serial for that
2378  * fw_card, which must not simultaneously contend with the removal of the
2379  * last peer for a given fw_card triggering the destruction of the same
2380  * fw_serial for the same fw_card.
2381  */
2382 static int fwserial_probe(struct fw_unit *unit,
2383                           const struct ieee1394_device_id *id)
2384 {
2385         struct fw_serial *serial;
2386         int err;
2387 
2388         mutex_lock(&fwserial_list_mutex);
2389         serial = fwserial_lookup(fw_parent_device(unit)->card);
2390         if (!serial)
2391                 err = fwserial_create(unit);
2392         else
2393                 err = fwserial_add_peer(serial, unit);
2394         mutex_unlock(&fwserial_list_mutex);
2395         return err;
2396 }
2397 
2398 /**
2399  * fwserial_remove: bus removal function for firewire 'serial' unit devices
2400  *
2401  * The corresponding 'peer' for this unit device is removed from the list of
2402  * peers for the associated fw_serial (which has a 1:1 correspondence with a
2403  * specific fw_card). If this is the last peer being removed, then trigger
2404  * the destruction of the underlying TTYs.
2405  */
2406 static void fwserial_remove(struct fw_unit *unit)
2407 {
2408         struct fwtty_peer *peer = dev_get_drvdata(&unit->device);
2409         struct fw_serial *serial = peer->serial;
2410         int i;
2411 
2412         mutex_lock(&fwserial_list_mutex);
2413         fwserial_remove_peer(peer);
2414 
2415         if (list_empty(&serial->peer_list)) {
2416                 /* unlink from the fwserial_list here */
2417                 list_del_rcu(&serial->list);
2418 
2419                 debugfs_remove_recursive(serial->debugfs);
2420 
2421                 for (i = 0; i < num_ttys; ++i)
2422                         fwserial_close_port(fwtty_driver, serial->ports[i]);
2423                 if (create_loop_dev)
2424                         fwserial_close_port(fwloop_driver, serial->ports[i]);
2425                 kref_put(&serial->kref, fwserial_destroy);
2426         }
2427         mutex_unlock(&fwserial_list_mutex);
2428 }
2429 
2430 /**
2431  * fwserial_update: bus update function for 'firewire' serial unit devices
2432  *
2433  * Updates the new node_id and bus generation for this peer. Note that locking
2434  * is unnecessary; but careful memory barrier usage is important to enforce the
2435  * load and store order of generation & node_id.
2436  *
2437  * The fw-core orders the write of node_id before generation in the parent
2438  * fw_device to ensure that a stale node_id cannot be used with a current
2439  * bus generation. So the generation value must be read before the node_id.
2440  *
2441  * In turn, this orders the write of node_id before generation in the peer to
2442  * also ensure a stale node_id cannot be used with a current bus generation.
2443  */
2444 static void fwserial_update(struct fw_unit *unit)
2445 {
2446         struct fw_device *parent = fw_parent_device(unit);
2447         struct fwtty_peer *peer = dev_get_drvdata(&unit->device);
2448         int generation;
2449 
2450         generation = parent->generation;
2451         smp_rmb();
2452         peer->node_id = parent->node_id;
2453         smp_wmb();
2454         peer->generation = generation;
2455 }
2456 
2457 static const struct ieee1394_device_id fwserial_id_table[] = {
2458         {
2459                 .match_flags  = IEEE1394_MATCH_SPECIFIER_ID |
2460                                 IEEE1394_MATCH_VERSION,
2461                 .specifier_id = LINUX_VENDOR_ID,
2462                 .version      = FWSERIAL_VERSION,
2463         },
2464         { }
2465 };
2466 
2467 static struct fw_driver fwserial_driver = {
2468         .driver = {
2469                 .owner  = THIS_MODULE,
2470                 .name   = KBUILD_MODNAME,
2471                 .bus    = &fw_bus_type,
2472         },
2473         .probe    = fwserial_probe,
2474         .update   = fwserial_update,
2475         .remove   = fwserial_remove,
2476         .id_table = fwserial_id_table,
2477 };
2478 
2479 #define FW_UNIT_SPECIFIER(id)   ((CSR_SPECIFIER_ID << 24) | (id))
2480 #define FW_UNIT_VERSION(ver)    ((CSR_VERSION << 24) | (ver))
2481 #define FW_UNIT_ADDRESS(ofs)    (((CSR_OFFSET | CSR_DEPENDENT_INFO) << 24)  \
2482                                  | (((ofs) - CSR_REGISTER_BASE) >> 2))
2483 /* XXX: config ROM definitons could be improved with semi-automated offset
2484  * and length calculation
2485  */
2486 #define FW_ROM_LEN(quads)       ((quads) << 16)
2487 #define FW_ROM_DESCRIPTOR(ofs)  (((CSR_LEAF | CSR_DESCRIPTOR) << 24) | (ofs))
2488 
2489 struct fwserial_unit_directory_data {
2490         u32     len_crc;
2491         u32     unit_specifier;
2492         u32     unit_sw_version;
2493         u32     unit_addr_offset;
2494         u32     desc1_ofs;
2495         u32     desc1_len_crc;
2496         u32     desc1_data[5];
2497 } __packed;
2498 
2499 static struct fwserial_unit_directory_data fwserial_unit_directory_data = {
2500         .len_crc = FW_ROM_LEN(4),
2501         .unit_specifier = FW_UNIT_SPECIFIER(LINUX_VENDOR_ID),
2502         .unit_sw_version = FW_UNIT_VERSION(FWSERIAL_VERSION),
2503         .desc1_ofs = FW_ROM_DESCRIPTOR(1),
2504         .desc1_len_crc = FW_ROM_LEN(5),
2505         .desc1_data = {
2506                 0x00000000,                     /*   type = text            */
2507                 0x00000000,                     /*   enc = ASCII, lang EN   */
2508                 0x4c696e75,                     /* 'Linux TTY'              */
2509                 0x78205454,
2510                 0x59000000,
2511         },
2512 };
2513 
2514 static struct fw_descriptor fwserial_unit_directory = {
2515         .length = sizeof(fwserial_unit_directory_data) / sizeof(u32),
2516         .key    = (CSR_DIRECTORY | CSR_UNIT) << 24,
2517         .data   = (u32 *)&fwserial_unit_directory_data,
2518 };
2519 
2520 /*
2521  * The management address is in the unit space region but above other known
2522  * address users (to keep wild writes from causing havoc)
2523  */
2524 static const struct fw_address_region fwserial_mgmt_addr_region = {
2525         .start = CSR_REGISTER_BASE + 0x1e0000ULL,
2526         .end = 0x1000000000000ULL,
2527 };
2528 
2529 static struct fw_address_handler fwserial_mgmt_addr_handler;
2530 
2531 /**
2532  * fwserial_handle_plug_req - handle VIRT_CABLE_PLUG request work
2533  * @work: ptr to peer->work
2534  *
2535  * Attempts to complete the VIRT_CABLE_PLUG handshake sequence for this peer.
2536  *
2537  * This checks for a collided request-- ie, that a VIRT_CABLE_PLUG request was
2538  * already sent to this peer. If so, the collision is resolved by comparing
2539  * guid values; the loser sends the plug response.
2540  *
2541  * Note: if an error prevents a response, don't do anything -- the
2542  * remote will timeout its request.
2543  */
2544 static void fwserial_handle_plug_req(struct work_struct *work)
2545 {
2546         struct fwtty_peer *peer = to_peer(work, work);
2547         struct virt_plug_params *plug_req = &peer->work_params.plug_req;
2548         struct fwtty_port *port;
2549         struct fwserial_mgmt_pkt *pkt;
2550         int rcode;
2551 
2552         pkt = kmalloc(sizeof(*pkt), GFP_KERNEL);
2553         if (!pkt)
2554                 return;
2555 
2556         port = fwserial_find_port(peer);
2557 
2558         spin_lock_bh(&peer->lock);
2559 
2560         switch (peer->state) {
2561         case FWPS_NOT_ATTACHED:
2562                 if (!port) {
2563                         fwtty_err(&peer->unit, "no more ports avail\n");
2564                         fill_plug_rsp_nack(pkt);
2565                 } else {
2566                         peer->port = port;
2567                         fill_plug_rsp_ok(pkt, peer->port);
2568                         peer_set_state(peer, FWPS_PLUG_RESPONDING);
2569                         /* don't release claimed port */
2570                         port = NULL;
2571                 }
2572                 break;
2573 
2574         case FWPS_PLUG_PENDING:
2575                 if (peer->serial->card->guid > peer->guid)
2576                         goto cleanup;
2577 
2578                 /* We lost - hijack the already-claimed port and send ok */
2579                 del_timer(&peer->timer);
2580                 fill_plug_rsp_ok(pkt, peer->port);
2581                 peer_set_state(peer, FWPS_PLUG_RESPONDING);
2582                 break;
2583 
2584         default:
2585                 fill_plug_rsp_nack(pkt);
2586         }
2587 
2588         spin_unlock_bh(&peer->lock);
2589         if (port)
2590                 fwserial_release_port(port, false);
2591 
2592         rcode = fwserial_send_mgmt_sync(peer, pkt);
2593 
2594         spin_lock_bh(&peer->lock);
2595         if (peer->state == FWPS_PLUG_RESPONDING) {
2596                 if (rcode == RCODE_COMPLETE) {
2597                         struct fwtty_port *tmp = peer->port;
2598 
2599                         fwserial_virt_plug_complete(peer, plug_req);
2600                         spin_unlock_bh(&peer->lock);
2601 
2602                         fwtty_write_port_status(tmp);
2603                         spin_lock_bh(&peer->lock);
2604                 } else {
2605                         fwtty_err(&peer->unit, "PLUG_RSP error (%d)\n", rcode);
2606                         port = peer_revert_state(peer);
2607                 }
2608         }
2609 cleanup:
2610         spin_unlock_bh(&peer->lock);
2611         if (port)
2612                 fwserial_release_port(port, false);
2613         kfree(pkt);
2614         return;
2615 }
2616 
2617 static void fwserial_handle_unplug_req(struct work_struct *work)
2618 {
2619         struct fwtty_peer *peer = to_peer(work, work);
2620         struct fwtty_port *port = NULL;
2621         struct fwserial_mgmt_pkt *pkt;
2622         int rcode;
2623 
2624         pkt = kmalloc(sizeof(*pkt), GFP_KERNEL);
2625         if (!pkt)
2626                 return;
2627 
2628         spin_lock_bh(&peer->lock);
2629 
2630         switch (peer->state) {
2631         case FWPS_ATTACHED:
2632                 fill_unplug_rsp_ok(pkt);
2633                 peer_set_state(peer, FWPS_UNPLUG_RESPONDING);
2634                 break;
2635 
2636         case FWPS_UNPLUG_PENDING:
2637                 if (peer->serial->card->guid > peer->guid)
2638                         goto cleanup;
2639 
2640                 /* We lost - send unplug rsp */
2641                 del_timer(&peer->timer);
2642                 fill_unplug_rsp_ok(pkt);
2643                 peer_set_state(peer, FWPS_UNPLUG_RESPONDING);
2644                 break;
2645 
2646         default:
2647                 fill_unplug_rsp_nack(pkt);
2648         }
2649 
2650         spin_unlock_bh(&peer->lock);
2651 
2652         rcode = fwserial_send_mgmt_sync(peer, pkt);
2653 
2654         spin_lock_bh(&peer->lock);
2655         if (peer->state == FWPS_UNPLUG_RESPONDING) {
2656                 if (rcode != RCODE_COMPLETE)
2657                         fwtty_err(&peer->unit, "UNPLUG_RSP error (%d)\n",
2658                                   rcode);
2659                 port = peer_revert_state(peer);
2660         }
2661 cleanup:
2662         spin_unlock_bh(&peer->lock);
2663         if (port)
2664                 fwserial_release_port(port, true);
2665         kfree(pkt);
2666         return;
2667 }
2668 
2669 static int fwserial_parse_mgmt_write(struct fwtty_peer *peer,
2670                                      struct fwserial_mgmt_pkt *pkt,
2671                                      unsigned long long addr,
2672                                      size_t len)
2673 {
2674         struct fwtty_port *port = NULL;
2675         bool reset = false;
2676         int rcode;
2677 
2678         if (addr != fwserial_mgmt_addr_handler.offset || len < sizeof(pkt->hdr))
2679                 return RCODE_ADDRESS_ERROR;
2680 
2681         if (len != be16_to_cpu(pkt->hdr.len) ||
2682             len != mgmt_pkt_expected_len(pkt->hdr.code))
2683                 return RCODE_DATA_ERROR;
2684 
2685         spin_lock_bh(&peer->lock);
2686         if (peer->state == FWPS_GONE) {
2687                 /*
2688                  * This should never happen - it would mean that the
2689                  * remote unit that just wrote this transaction was
2690                  * already removed from the bus -- and the removal was
2691                  * processed before we rec'd this transaction
2692                  */
2693                 fwtty_err(&peer->unit, "peer already removed\n");
2694                 spin_unlock_bh(&peer->lock);
2695                 return RCODE_ADDRESS_ERROR;
2696         }
2697 
2698         rcode = RCODE_COMPLETE;
2699 
2700         fwtty_dbg(&peer->unit, "mgmt: hdr.code: %04hx\n", pkt->hdr.code);
2701 
2702         switch (be16_to_cpu(pkt->hdr.code) & FWSC_CODE_MASK) {
2703         case FWSC_VIRT_CABLE_PLUG:
2704                 if (work_pending(&peer->work)) {
2705                         fwtty_err(&peer->unit, "plug req: busy\n");
2706                         rcode = RCODE_CONFLICT_ERROR;
2707 
2708                 } else {
2709                         peer->work_params.plug_req = pkt->plug_req;
2710                         peer->workfn = fwserial_handle_plug_req;
2711                         queue_work(system_unbound_wq, &peer->work);
2712                 }
2713                 break;
2714 
2715         case FWSC_VIRT_CABLE_PLUG_RSP:
2716                 if (peer->state != FWPS_PLUG_PENDING) {
2717                         rcode = RCODE_CONFLICT_ERROR;
2718 
2719                 } else if (be16_to_cpu(pkt->hdr.code) & FWSC_RSP_NACK) {
2720                         fwtty_notice(&peer->unit, "NACK plug rsp\n");
2721                         port = peer_revert_state(peer);
2722 
2723                 } else {
2724                         struct fwtty_port *tmp = peer->port;
2725 
2726                         fwserial_virt_plug_complete(peer, &pkt->plug_rsp);
2727                         spin_unlock_bh(&peer->lock);
2728 
2729                         fwtty_write_port_status(tmp);
2730                         spin_lock_bh(&peer->lock);
2731                 }
2732                 break;
2733 
2734         case FWSC_VIRT_CABLE_UNPLUG:
2735                 if (work_pending(&peer->work)) {
2736                         fwtty_err(&peer->unit, "unplug req: busy\n");
2737                         rcode = RCODE_CONFLICT_ERROR;
2738                 } else {
2739                         peer->workfn = fwserial_handle_unplug_req;
2740                         queue_work(system_unbound_wq, &peer->work);
2741                 }
2742                 break;
2743 
2744         case FWSC_VIRT_CABLE_UNPLUG_RSP:
2745                 if (peer->state != FWPS_UNPLUG_PENDING) {
2746                         rcode = RCODE_CONFLICT_ERROR;
2747                 } else {
2748                         if (be16_to_cpu(pkt->hdr.code) & FWSC_RSP_NACK)
2749                                 fwtty_notice(&peer->unit, "NACK unplug?\n");
2750                         port = peer_revert_state(peer);
2751                         reset = true;
2752                 }
2753                 break;
2754 
2755         default:
2756                 fwtty_err(&peer->unit, "unknown mgmt code %d\n",
2757                           be16_to_cpu(pkt->hdr.code));
2758                 rcode = RCODE_DATA_ERROR;
2759         }
2760         spin_unlock_bh(&peer->lock);
2761 
2762         if (port)
2763                 fwserial_release_port(port, reset);
2764 
2765         return rcode;
2766 }
2767 
2768 /**
2769  * fwserial_mgmt_handler: bus address handler for mgmt requests
2770  * @parameters: fw_address_callback_t as specified by firewire core interface
2771  *
2772  * This handler is responsible for handling virtual cable requests from remotes
2773  * for all cards.
2774  */
2775 static void fwserial_mgmt_handler(struct fw_card *card,
2776                                   struct fw_request *request,
2777                                   int tcode, int destination, int source,
2778                                   int generation,
2779                                   unsigned long long addr,
2780                                   void *data, size_t len,
2781                                   void *callback_data)
2782 {
2783         struct fwserial_mgmt_pkt *pkt = data;
2784         struct fwtty_peer *peer;
2785         int rcode;
2786 
2787         rcu_read_lock();
2788         peer = __fwserial_peer_by_node_id(card, generation, source);
2789         if (!peer) {
2790                 fwtty_dbg(card, "peer(%d:%x) not found\n", generation, source);
2791                 __dump_peer_list(card);
2792                 rcode = RCODE_CONFLICT_ERROR;
2793 
2794         } else {
2795                 switch (tcode) {
2796                 case TCODE_WRITE_BLOCK_REQUEST:
2797                         rcode = fwserial_parse_mgmt_write(peer, pkt, addr, len);
2798                         break;
2799 
2800                 default:
2801                         rcode = RCODE_TYPE_ERROR;
2802                 }
2803         }
2804 
2805         rcu_read_unlock();
2806         fw_send_response(card, request, rcode);
2807 }
2808 
2809 static int __init fwserial_init(void)
2810 {
2811         int err, num_loops = !!(create_loop_dev);
2812 
2813         /* XXX: placeholder for a "firewire" debugfs node */
2814         fwserial_debugfs = debugfs_create_dir(KBUILD_MODNAME, NULL);
2815 
2816         /* num_ttys/num_ports must not be set above the static alloc avail */
2817         if (num_ttys + num_loops > MAX_CARD_PORTS)
2818                 num_ttys = MAX_CARD_PORTS - num_loops;
2819         num_ports = num_ttys + num_loops;
2820 
2821         fwtty_driver = tty_alloc_driver(MAX_TOTAL_PORTS, TTY_DRIVER_REAL_RAW
2822                                         | TTY_DRIVER_DYNAMIC_DEV);
2823         if (IS_ERR(fwtty_driver)) {
2824                 err = PTR_ERR(fwtty_driver);
2825                 return err;
2826         }
2827 
2828         fwtty_driver->driver_name       = KBUILD_MODNAME;
2829         fwtty_driver->name              = tty_dev_name;
2830         fwtty_driver->major             = 0;
2831         fwtty_driver->minor_start       = 0;
2832         fwtty_driver->type              = TTY_DRIVER_TYPE_SERIAL;
2833         fwtty_driver->subtype           = SERIAL_TYPE_NORMAL;
2834         fwtty_driver->init_termios          = tty_std_termios;
2835         fwtty_driver->init_termios.c_cflag  |= CLOCAL;
2836         tty_set_operations(fwtty_driver, &fwtty_ops);
2837 
2838         err = tty_register_driver(fwtty_driver);
2839         if (err) {
2840                 pr_err("register tty driver failed (%d)\n", err);
2841                 goto put_tty;
2842         }
2843 
2844         if (create_loop_dev) {
2845                 fwloop_driver = tty_alloc_driver(MAX_TOTAL_PORTS / num_ports,
2846                                                  TTY_DRIVER_REAL_RAW
2847                                                  | TTY_DRIVER_DYNAMIC_DEV);
2848                 if (IS_ERR(fwloop_driver)) {
2849                         err = PTR_ERR(fwloop_driver);
2850                         goto unregister_driver;
2851                 }
2852 
2853                 fwloop_driver->driver_name      = KBUILD_MODNAME "_loop";
2854                 fwloop_driver->name             = loop_dev_name;
2855                 fwloop_driver->major            = 0;
2856                 fwloop_driver->minor_start      = 0;
2857                 fwloop_driver->type             = TTY_DRIVER_TYPE_SERIAL;
2858                 fwloop_driver->subtype          = SERIAL_TYPE_NORMAL;
2859                 fwloop_driver->init_termios         = tty_std_termios;
2860                 fwloop_driver->init_termios.c_cflag  |= CLOCAL;
2861                 tty_set_operations(fwloop_driver, &fwloop_ops);
2862 
2863                 err = tty_register_driver(fwloop_driver);
2864                 if (err) {
2865                         pr_err("register loop driver failed (%d)\n", err);
2866                         goto put_loop;
2867                 }
2868         }
2869 
2870         fwtty_txn_cache = kmem_cache_create("fwtty_txn_cache",
2871                                             sizeof(struct fwtty_transaction),
2872                                             0, 0, fwtty_txn_constructor);
2873         if (!fwtty_txn_cache) {
2874                 err = -ENOMEM;
2875                 goto unregister_loop;
2876         }
2877 
2878         /*
2879          * Ideally, this address handler would be registered per local node
2880          * (rather than the same handler for all local nodes). However,
2881          * since the firewire core requires the config rom descriptor *before*
2882          * the local unit device(s) are created, a single management handler
2883          * must suffice for all local serial units.
2884          */
2885         fwserial_mgmt_addr_handler.length = sizeof(struct fwserial_mgmt_pkt);
2886         fwserial_mgmt_addr_handler.address_callback = fwserial_mgmt_handler;
2887 
2888         err = fw_core_add_address_handler(&fwserial_mgmt_addr_handler,
2889                                           &fwserial_mgmt_addr_region);
2890         if (err) {
2891                 pr_err("add management handler failed (%d)\n", err);
2892                 goto destroy_cache;
2893         }
2894 
2895         fwserial_unit_directory_data.unit_addr_offset =
2896                 FW_UNIT_ADDRESS(fwserial_mgmt_addr_handler.offset);
2897         err = fw_core_add_descriptor(&fwserial_unit_directory);
2898         if (err) {
2899                 pr_err("add unit descriptor failed (%d)\n", err);
2900                 goto remove_handler;
2901         }
2902 
2903         err = driver_register(&fwserial_driver.driver);
2904         if (err) {
2905                 pr_err("register fwserial driver failed (%d)\n", err);
2906                 goto remove_descriptor;
2907         }
2908 
2909         return 0;
2910 
2911 remove_descriptor:
2912         fw_core_remove_descriptor(&fwserial_unit_directory);
2913 remove_handler:
2914         fw_core_remove_address_handler(&fwserial_mgmt_addr_handler);
2915 destroy_cache:
2916         kmem_cache_destroy(fwtty_txn_cache);
2917 unregister_loop:
2918         if (create_loop_dev)
2919                 tty_unregister_driver(fwloop_driver);
2920 put_loop:
2921         if (create_loop_dev)
2922                 put_tty_driver(fwloop_driver);
2923 unregister_driver:
2924         tty_unregister_driver(fwtty_driver);
2925 put_tty:
2926         put_tty_driver(fwtty_driver);
2927         debugfs_remove_recursive(fwserial_debugfs);
2928         return err;
2929 }
2930 
2931 static void __exit fwserial_exit(void)
2932 {
2933         driver_unregister(&fwserial_driver.driver);
2934         fw_core_remove_descriptor(&fwserial_unit_directory);
2935         fw_core_remove_address_handler(&fwserial_mgmt_addr_handler);
2936         kmem_cache_destroy(fwtty_txn_cache);
2937         if (create_loop_dev) {
2938                 tty_unregister_driver(fwloop_driver);
2939                 put_tty_driver(fwloop_driver);
2940         }
2941         tty_unregister_driver(fwtty_driver);
2942         put_tty_driver(fwtty_driver);
2943         debugfs_remove_recursive(fwserial_debugfs);
2944 }
2945 
2946 module_init(fwserial_init);
2947 module_exit(fwserial_exit);
2948 
2949 MODULE_AUTHOR("Peter Hurley (peter@hurleysoftware.com)");
2950 MODULE_DESCRIPTION("FireWire Serial TTY Driver");
2951 MODULE_LICENSE("GPL");
2952 MODULE_DEVICE_TABLE(ieee1394, fwserial_id_table);
2953 MODULE_PARM_DESC(ttys, "Number of ttys to create for each local firewire node");
2954 MODULE_PARM_DESC(auto, "Auto-connect a tty to each firewire node discovered");
2955 MODULE_PARM_DESC(loop, "Create a loopback device, fwloop<n>, with ttys");
2956 

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