Version:  2.0.40 2.2.26 2.4.37 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1

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

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