Version:  2.0.40 2.2.26 2.4.37 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 4.2 4.3 4.4 4.5

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 static void fwtty_port_put(struct fwtty_port *port)
897 {
898         kref_put(&port->serial->kref, fwserial_destroy);
899 }
900 
901 static void fwtty_port_dtr_rts(struct tty_port *tty_port, int on)
902 {
903         struct fwtty_port *port = to_port(tty_port, port);
904 
905         fwtty_dbg(port, "on/off: %d\n", on);
906 
907         spin_lock_bh(&port->lock);
908         /* Don't change carrier state if this is a console */
909         if (!port->port.console) {
910                 if (on)
911                         port->mctrl |= TIOCM_DTR | TIOCM_RTS;
912                 else
913                         port->mctrl &= ~(TIOCM_DTR | TIOCM_RTS);
914         }
915 
916         __fwtty_write_port_status(port);
917         spin_unlock_bh(&port->lock);
918 }
919 
920 /**
921  * fwtty_port_carrier_raised: required tty_port operation
922  *
923  * This port operation is polled after a tty has been opened and is waiting for
924  * carrier detect -- see drivers/tty/tty_port:tty_port_block_til_ready().
925  */
926 static int fwtty_port_carrier_raised(struct tty_port *tty_port)
927 {
928         struct fwtty_port *port = to_port(tty_port, port);
929         int rc;
930 
931         rc = (port->mstatus & TIOCM_CAR);
932 
933         fwtty_dbg(port, "%d\n", rc);
934 
935         return rc;
936 }
937 
938 static unsigned set_termios(struct fwtty_port *port, struct tty_struct *tty)
939 {
940         unsigned baud, frame;
941 
942         baud = tty_termios_baud_rate(&tty->termios);
943         tty_termios_encode_baud_rate(&tty->termios, baud, baud);
944 
945         /* compute bit count of 2 frames */
946         frame = 12 + ((C_CSTOPB(tty)) ? 4 : 2) + ((C_PARENB(tty)) ? 2 : 0);
947 
948         switch (C_CSIZE(tty)) {
949         case CS5:
950                 frame -= (C_CSTOPB(tty)) ? 1 : 0;
951                 break;
952         case CS6:
953                 frame += 2;
954                 break;
955         case CS7:
956                 frame += 4;
957                 break;
958         case CS8:
959                 frame += 6;
960                 break;
961         }
962 
963         port->cps = (baud << 1) / frame;
964 
965         port->status_mask = UART_LSR_OE;
966         if (_I_FLAG(tty, BRKINT | PARMRK))
967                 port->status_mask |= UART_LSR_BI;
968 
969         port->ignore_mask = 0;
970         if (I_IGNBRK(tty)) {
971                 port->ignore_mask |= UART_LSR_BI;
972                 if (I_IGNPAR(tty))
973                         port->ignore_mask |= UART_LSR_OE;
974         }
975 
976         port->write_only = !C_CREAD(tty);
977 
978         /* turn off echo and newline xlat if loopback */
979         if (port->loopback) {
980                 tty->termios.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHOKE |
981                                           ECHONL | ECHOPRT | ECHOCTL);
982                 tty->termios.c_oflag &= ~ONLCR;
983         }
984 
985         return baud;
986 }
987 
988 static int fwtty_port_activate(struct tty_port *tty_port,
989                                struct tty_struct *tty)
990 {
991         struct fwtty_port *port = to_port(tty_port, port);
992         unsigned baud;
993         int err;
994 
995         set_bit(TTY_IO_ERROR, &tty->flags);
996 
997         err = dma_fifo_alloc(&port->tx_fifo, FWTTY_PORT_TXFIFO_LEN,
998                              cache_line_size(),
999                              port->max_payload,
1000                              FWTTY_PORT_MAX_PEND_DMA,
1001                              GFP_KERNEL);
1002         if (err)
1003                 return err;
1004 
1005         spin_lock_bh(&port->lock);
1006 
1007         baud = set_termios(port, tty);
1008 
1009         /* if console, don't change carrier state */
1010         if (!port->port.console) {
1011                 port->mctrl = 0;
1012                 if (baud != 0)
1013                         port->mctrl = TIOCM_DTR | TIOCM_RTS;
1014         }
1015 
1016         if (C_CRTSCTS(tty) && ~port->mstatus & TIOCM_CTS)
1017                 tty->hw_stopped = 1;
1018 
1019         __fwtty_write_port_status(port);
1020         spin_unlock_bh(&port->lock);
1021 
1022         clear_bit(TTY_IO_ERROR, &tty->flags);
1023 
1024         return 0;
1025 }
1026 
1027 /**
1028  * fwtty_port_shutdown
1029  *
1030  * Note: the tty port core ensures this is not the console and
1031  * manages TTY_IO_ERROR properly
1032  */
1033 static void fwtty_port_shutdown(struct tty_port *tty_port)
1034 {
1035         struct fwtty_port *port = to_port(tty_port, port);
1036 
1037         /* TODO: cancel outstanding transactions */
1038 
1039         cancel_delayed_work_sync(&port->emit_breaks);
1040         cancel_delayed_work_sync(&port->drain);
1041 
1042         spin_lock_bh(&port->lock);
1043         port->flags = 0;
1044         port->break_ctl = 0;
1045         port->overrun = 0;
1046         __fwtty_write_port_status(port);
1047         dma_fifo_free(&port->tx_fifo);
1048         spin_unlock_bh(&port->lock);
1049 }
1050 
1051 static int fwtty_open(struct tty_struct *tty, struct file *fp)
1052 {
1053         struct fwtty_port *port = tty->driver_data;
1054 
1055         return tty_port_open(&port->port, tty, fp);
1056 }
1057 
1058 static void fwtty_close(struct tty_struct *tty, struct file *fp)
1059 {
1060         struct fwtty_port *port = tty->driver_data;
1061 
1062         tty_port_close(&port->port, tty, fp);
1063 }
1064 
1065 static void fwtty_hangup(struct tty_struct *tty)
1066 {
1067         struct fwtty_port *port = tty->driver_data;
1068 
1069         tty_port_hangup(&port->port);
1070 }
1071 
1072 static void fwtty_cleanup(struct tty_struct *tty)
1073 {
1074         struct fwtty_port *port = tty->driver_data;
1075 
1076         tty->driver_data = NULL;
1077         fwtty_port_put(port);
1078 }
1079 
1080 static int fwtty_install(struct tty_driver *driver, struct tty_struct *tty)
1081 {
1082         struct fwtty_port *port = fwtty_port_get(tty->index);
1083         int err;
1084 
1085         err = tty_standard_install(driver, tty);
1086         if (!err)
1087                 tty->driver_data = port;
1088         else
1089                 fwtty_port_put(port);
1090         return err;
1091 }
1092 
1093 static int fwloop_install(struct tty_driver *driver, struct tty_struct *tty)
1094 {
1095         struct fwtty_port *port = fwtty_port_get(table_idx(tty->index));
1096         int err;
1097 
1098         err = tty_standard_install(driver, tty);
1099         if (!err)
1100                 tty->driver_data = port;
1101         else
1102                 fwtty_port_put(port);
1103         return err;
1104 }
1105 
1106 static int fwtty_write(struct tty_struct *tty, const unsigned char *buf, int c)
1107 {
1108         struct fwtty_port *port = tty->driver_data;
1109         int n, len;
1110 
1111         fwtty_dbg(port, "%d\n", c);
1112         fwtty_profile_data(port->stats.writes, c);
1113 
1114         spin_lock_bh(&port->lock);
1115         n = dma_fifo_in(&port->tx_fifo, buf, c);
1116         len = dma_fifo_out_level(&port->tx_fifo);
1117         if (len < DRAIN_THRESHOLD)
1118                 schedule_delayed_work(&port->drain, 1);
1119         spin_unlock_bh(&port->lock);
1120 
1121         if (len >= DRAIN_THRESHOLD)
1122                 fwtty_tx(port, false);
1123 
1124         debug_short_write(port, c, n);
1125 
1126         return (n < 0) ? 0 : n;
1127 }
1128 
1129 static int fwtty_write_room(struct tty_struct *tty)
1130 {
1131         struct fwtty_port *port = tty->driver_data;
1132         int n;
1133 
1134         spin_lock_bh(&port->lock);
1135         n = dma_fifo_avail(&port->tx_fifo);
1136         spin_unlock_bh(&port->lock);
1137 
1138         fwtty_dbg(port, "%d\n", n);
1139 
1140         return n;
1141 }
1142 
1143 static int fwtty_chars_in_buffer(struct tty_struct *tty)
1144 {
1145         struct fwtty_port *port = tty->driver_data;
1146         int n;
1147 
1148         spin_lock_bh(&port->lock);
1149         n = dma_fifo_level(&port->tx_fifo);
1150         spin_unlock_bh(&port->lock);
1151 
1152         fwtty_dbg(port, "%d\n", n);
1153 
1154         return n;
1155 }
1156 
1157 static void fwtty_send_xchar(struct tty_struct *tty, char ch)
1158 {
1159         struct fwtty_port *port = tty->driver_data;
1160 
1161         fwtty_dbg(port, "%02x\n", ch);
1162 
1163         fwtty_write_xchar(port, ch);
1164 }
1165 
1166 static void fwtty_throttle(struct tty_struct *tty)
1167 {
1168         struct fwtty_port *port = tty->driver_data;
1169 
1170         /*
1171          * Ignore throttling (but not unthrottling).
1172          * It only makes sense to throttle when data will no longer be
1173          * accepted by the tty flip buffer. For example, it is
1174          * possible for received data to overflow the tty buffer long
1175          * before the line discipline ever has a chance to throttle the driver.
1176          * Additionally, the driver may have already completed the I/O
1177          * but the tty buffer is still emptying, so the line discipline is
1178          * throttling and unthrottling nothing.
1179          */
1180 
1181         ++port->stats.throttled;
1182 }
1183 
1184 static void fwtty_unthrottle(struct tty_struct *tty)
1185 {
1186         struct fwtty_port *port = tty->driver_data;
1187 
1188         fwtty_dbg(port, "CRTSCTS: %d\n", C_CRTSCTS(tty) != 0);
1189 
1190         fwtty_profile_fifo(port, port->stats.unthrottle);
1191 
1192         spin_lock_bh(&port->lock);
1193         port->mctrl &= ~OOB_RX_THROTTLE;
1194         if (C_CRTSCTS(tty))
1195                 port->mctrl |= TIOCM_RTS;
1196         __fwtty_write_port_status(port);
1197         spin_unlock_bh(&port->lock);
1198 }
1199 
1200 static int check_msr_delta(struct fwtty_port *port, unsigned long mask,
1201                            struct async_icount *prev)
1202 {
1203         struct async_icount now;
1204         int delta;
1205 
1206         now = port->icount;
1207 
1208         delta = ((mask & TIOCM_RNG && prev->rng != now.rng) ||
1209                  (mask & TIOCM_DSR && prev->dsr != now.dsr) ||
1210                  (mask & TIOCM_CAR && prev->dcd != now.dcd) ||
1211                  (mask & TIOCM_CTS && prev->cts != now.cts));
1212 
1213         *prev = now;
1214 
1215         return delta;
1216 }
1217 
1218 static int wait_msr_change(struct fwtty_port *port, unsigned long mask)
1219 {
1220         struct async_icount prev;
1221 
1222         prev = port->icount;
1223 
1224         return wait_event_interruptible(port->port.delta_msr_wait,
1225                                         check_msr_delta(port, mask, &prev));
1226 }
1227 
1228 static int get_serial_info(struct fwtty_port *port,
1229                            struct serial_struct __user *info)
1230 {
1231         struct serial_struct tmp;
1232 
1233         memset(&tmp, 0, sizeof(tmp));
1234 
1235         tmp.type =  PORT_UNKNOWN;
1236         tmp.line =  port->port.tty->index;
1237         tmp.flags = port->port.flags;
1238         tmp.xmit_fifo_size = FWTTY_PORT_TXFIFO_LEN;
1239         tmp.baud_base = 400000000;
1240         tmp.close_delay = port->port.close_delay;
1241 
1242         return (copy_to_user(info, &tmp, sizeof(*info))) ? -EFAULT : 0;
1243 }
1244 
1245 static int set_serial_info(struct fwtty_port *port,
1246                            struct serial_struct __user *info)
1247 {
1248         struct serial_struct tmp;
1249 
1250         if (copy_from_user(&tmp, info, sizeof(tmp)))
1251                 return -EFAULT;
1252 
1253         if (tmp.irq != 0 || tmp.port != 0 || tmp.custom_divisor != 0 ||
1254             tmp.baud_base != 400000000)
1255                 return -EPERM;
1256 
1257         if (!capable(CAP_SYS_ADMIN)) {
1258                 if (((tmp.flags & ~ASYNC_USR_MASK) !=
1259                      (port->port.flags & ~ASYNC_USR_MASK)))
1260                         return -EPERM;
1261         } else {
1262                 port->port.close_delay = tmp.close_delay * HZ / 100;
1263         }
1264 
1265         return 0;
1266 }
1267 
1268 static int fwtty_ioctl(struct tty_struct *tty, unsigned cmd,
1269                        unsigned long arg)
1270 {
1271         struct fwtty_port *port = tty->driver_data;
1272         int err;
1273 
1274         switch (cmd) {
1275         case TIOCGSERIAL:
1276                 mutex_lock(&port->port.mutex);
1277                 err = get_serial_info(port, (void __user *)arg);
1278                 mutex_unlock(&port->port.mutex);
1279                 break;
1280 
1281         case TIOCSSERIAL:
1282                 mutex_lock(&port->port.mutex);
1283                 err = set_serial_info(port, (void __user *)arg);
1284                 mutex_unlock(&port->port.mutex);
1285                 break;
1286 
1287         case TIOCMIWAIT:
1288                 err = wait_msr_change(port, arg);
1289                 break;
1290 
1291         default:
1292                 err = -ENOIOCTLCMD;
1293         }
1294 
1295         return err;
1296 }
1297 
1298 static void fwtty_set_termios(struct tty_struct *tty, struct ktermios *old)
1299 {
1300         struct fwtty_port *port = tty->driver_data;
1301         unsigned baud;
1302 
1303         spin_lock_bh(&port->lock);
1304         baud = set_termios(port, tty);
1305 
1306         if ((baud == 0) && (old->c_cflag & CBAUD)) {
1307                 port->mctrl &= ~(TIOCM_DTR | TIOCM_RTS);
1308         } else if ((baud != 0) && !(old->c_cflag & CBAUD)) {
1309                 if (C_CRTSCTS(tty) || !test_bit(TTY_THROTTLED, &tty->flags))
1310                         port->mctrl |= TIOCM_DTR | TIOCM_RTS;
1311                 else
1312                         port->mctrl |= TIOCM_DTR;
1313         }
1314         __fwtty_write_port_status(port);
1315         spin_unlock_bh(&port->lock);
1316 
1317         if (old->c_cflag & CRTSCTS) {
1318                 if (!C_CRTSCTS(tty)) {
1319                         tty->hw_stopped = 0;
1320                         fwtty_restart_tx(port);
1321                 }
1322         } else if (C_CRTSCTS(tty) && ~port->mstatus & TIOCM_CTS) {
1323                 tty->hw_stopped = 1;
1324         }
1325 }
1326 
1327 /**
1328  * fwtty_break_ctl - start/stop sending breaks
1329  *
1330  * Signals the remote to start or stop generating simulated breaks.
1331  * First, stop dequeueing from the fifo and wait for writer/drain to leave tx
1332  * before signalling the break line status. This guarantees any pending rx will
1333  * be queued to the line discipline before break is simulated on the remote.
1334  * Conversely, turning off break_ctl requires signalling the line status change,
1335  * then enabling tx.
1336  */
1337 static int fwtty_break_ctl(struct tty_struct *tty, int state)
1338 {
1339         struct fwtty_port *port = tty->driver_data;
1340         long ret;
1341 
1342         fwtty_dbg(port, "%d\n", state);
1343 
1344         if (state == -1) {
1345                 set_bit(STOP_TX, &port->flags);
1346                 ret = wait_event_interruptible_timeout(port->wait_tx,
1347                                                !test_bit(IN_TX, &port->flags),
1348                                                10);
1349                 if (ret == 0 || ret == -ERESTARTSYS) {
1350                         clear_bit(STOP_TX, &port->flags);
1351                         fwtty_restart_tx(port);
1352                         return -EINTR;
1353                 }
1354         }
1355 
1356         spin_lock_bh(&port->lock);
1357         port->break_ctl = (state == -1);
1358         __fwtty_write_port_status(port);
1359         spin_unlock_bh(&port->lock);
1360 
1361         if (state == 0) {
1362                 spin_lock_bh(&port->lock);
1363                 dma_fifo_reset(&port->tx_fifo);
1364                 clear_bit(STOP_TX, &port->flags);
1365                 spin_unlock_bh(&port->lock);
1366         }
1367         return 0;
1368 }
1369 
1370 static int fwtty_tiocmget(struct tty_struct *tty)
1371 {
1372         struct fwtty_port *port = tty->driver_data;
1373         unsigned tiocm;
1374 
1375         spin_lock_bh(&port->lock);
1376         tiocm = (port->mctrl & MCTRL_MASK) | (port->mstatus & ~MCTRL_MASK);
1377         spin_unlock_bh(&port->lock);
1378 
1379         fwtty_dbg(port, "%x\n", tiocm);
1380 
1381         return tiocm;
1382 }
1383 
1384 static int fwtty_tiocmset(struct tty_struct *tty, unsigned set, unsigned clear)
1385 {
1386         struct fwtty_port *port = tty->driver_data;
1387 
1388         fwtty_dbg(port, "set: %x clear: %x\n", set, clear);
1389 
1390         /* TODO: simulate loopback if TIOCM_LOOP set */
1391 
1392         spin_lock_bh(&port->lock);
1393         port->mctrl &= ~(clear & MCTRL_MASK & 0xffff);
1394         port->mctrl |= set & MCTRL_MASK & 0xffff;
1395         __fwtty_write_port_status(port);
1396         spin_unlock_bh(&port->lock);
1397         return 0;
1398 }
1399 
1400 static int fwtty_get_icount(struct tty_struct *tty,
1401                             struct serial_icounter_struct *icount)
1402 {
1403         struct fwtty_port *port = tty->driver_data;
1404         struct stats stats;
1405 
1406         memcpy(&stats, &port->stats, sizeof(stats));
1407         if (port->port.console)
1408                 (*port->fwcon_ops->stats)(&stats, port->con_data);
1409 
1410         icount->cts = port->icount.cts;
1411         icount->dsr = port->icount.dsr;
1412         icount->rng = port->icount.rng;
1413         icount->dcd = port->icount.dcd;
1414         icount->rx  = port->icount.rx;
1415         icount->tx  = port->icount.tx + stats.xchars;
1416         icount->frame   = port->icount.frame;
1417         icount->overrun = port->icount.overrun;
1418         icount->parity  = port->icount.parity;
1419         icount->brk     = port->icount.brk;
1420         icount->buf_overrun = port->icount.overrun;
1421         return 0;
1422 }
1423 
1424 static void fwtty_proc_show_port(struct seq_file *m, struct fwtty_port *port)
1425 {
1426         struct stats stats;
1427 
1428         memcpy(&stats, &port->stats, sizeof(stats));
1429         if (port->port.console)
1430                 (*port->fwcon_ops->stats)(&stats, port->con_data);
1431 
1432         seq_printf(m, " addr:%012llx tx:%d rx:%d", port->rx_handler.offset,
1433                    port->icount.tx + stats.xchars, port->icount.rx);
1434         seq_printf(m, " cts:%d dsr:%d rng:%d dcd:%d", port->icount.cts,
1435                    port->icount.dsr, port->icount.rng, port->icount.dcd);
1436         seq_printf(m, " fe:%d oe:%d pe:%d brk:%d", port->icount.frame,
1437                    port->icount.overrun, port->icount.parity, port->icount.brk);
1438 }
1439 
1440 static void fwtty_debugfs_show_port(struct seq_file *m, struct fwtty_port *port)
1441 {
1442         struct stats stats;
1443 
1444         memcpy(&stats, &port->stats, sizeof(stats));
1445         if (port->port.console)
1446                 (*port->fwcon_ops->stats)(&stats, port->con_data);
1447 
1448         seq_printf(m, " dr:%d st:%d err:%d lost:%d", stats.dropped,
1449                    stats.tx_stall, stats.fifo_errs, stats.lost);
1450         seq_printf(m, " pkts:%d thr:%d", stats.sent, stats.throttled);
1451 
1452         if (port->port.console) {
1453                 seq_puts(m, "\n    ");
1454                 (*port->fwcon_ops->proc_show)(m, port->con_data);
1455         }
1456 
1457         fwtty_dump_profile(m, &port->stats);
1458 }
1459 
1460 static void fwtty_debugfs_show_peer(struct seq_file *m, struct fwtty_peer *peer)
1461 {
1462         int generation = peer->generation;
1463 
1464         smp_rmb();
1465         seq_printf(m, " %s:", dev_name(&peer->unit->device));
1466         seq_printf(m, " node:%04x gen:%d", peer->node_id, generation);
1467         seq_printf(m, " sp:%d max:%d guid:%016llx", peer->speed,
1468                    peer->max_payload, (unsigned long long) peer->guid);
1469         seq_printf(m, " mgmt:%012llx", (unsigned long long) peer->mgmt_addr);
1470         seq_printf(m, " addr:%012llx", (unsigned long long) peer->status_addr);
1471         seq_putc(m, '\n');
1472 }
1473 
1474 static int fwtty_proc_show(struct seq_file *m, void *v)
1475 {
1476         struct fwtty_port *port;
1477         int i;
1478 
1479         seq_puts(m, "fwserinfo: 1.0 driver: 1.0\n");
1480         for (i = 0; i < MAX_TOTAL_PORTS && (port = fwtty_port_get(i)); ++i) {
1481                 seq_printf(m, "%2d:", i);
1482                 if (capable(CAP_SYS_ADMIN))
1483                         fwtty_proc_show_port(m, port);
1484                 fwtty_port_put(port);
1485                 seq_puts(m, "\n");
1486         }
1487         return 0;
1488 }
1489 
1490 static int fwtty_debugfs_stats_show(struct seq_file *m, void *v)
1491 {
1492         struct fw_serial *serial = m->private;
1493         struct fwtty_port *port;
1494         int i;
1495 
1496         for (i = 0; i < num_ports; ++i) {
1497                 port = fwtty_port_get(serial->ports[i]->index);
1498                 if (port) {
1499                         seq_printf(m, "%2d:", port->index);
1500                         fwtty_proc_show_port(m, port);
1501                         fwtty_debugfs_show_port(m, port);
1502                         fwtty_port_put(port);
1503                         seq_puts(m, "\n");
1504                 }
1505         }
1506         return 0;
1507 }
1508 
1509 static int fwtty_debugfs_peers_show(struct seq_file *m, void *v)
1510 {
1511         struct fw_serial *serial = m->private;
1512         struct fwtty_peer *peer;
1513 
1514         rcu_read_lock();
1515         seq_printf(m, "card: %s  guid: %016llx\n",
1516                    dev_name(serial->card->device),
1517                    (unsigned long long) serial->card->guid);
1518         list_for_each_entry_rcu(peer, &serial->peer_list, list)
1519                 fwtty_debugfs_show_peer(m, peer);
1520         rcu_read_unlock();
1521         return 0;
1522 }
1523 
1524 static int fwtty_proc_open(struct inode *inode, struct file *fp)
1525 {
1526         return single_open(fp, fwtty_proc_show, NULL);
1527 }
1528 
1529 static int fwtty_stats_open(struct inode *inode, struct file *fp)
1530 {
1531         return single_open(fp, fwtty_debugfs_stats_show, inode->i_private);
1532 }
1533 
1534 static int fwtty_peers_open(struct inode *inode, struct file *fp)
1535 {
1536         return single_open(fp, fwtty_debugfs_peers_show, inode->i_private);
1537 }
1538 
1539 static const struct file_operations fwtty_stats_fops = {
1540         .owner =        THIS_MODULE,
1541         .open =         fwtty_stats_open,
1542         .read =         seq_read,
1543         .llseek =       seq_lseek,
1544         .release =      single_release,
1545 };
1546 
1547 static const struct file_operations fwtty_peers_fops = {
1548         .owner =        THIS_MODULE,
1549         .open =         fwtty_peers_open,
1550         .read =         seq_read,
1551         .llseek =       seq_lseek,
1552         .release =      single_release,
1553 };
1554 
1555 static const struct file_operations fwtty_proc_fops = {
1556         .owner =        THIS_MODULE,
1557         .open =         fwtty_proc_open,
1558         .read =         seq_read,
1559         .llseek =       seq_lseek,
1560         .release =      single_release,
1561 };
1562 
1563 static const struct tty_port_operations fwtty_port_ops = {
1564         .dtr_rts =              fwtty_port_dtr_rts,
1565         .carrier_raised =       fwtty_port_carrier_raised,
1566         .shutdown =             fwtty_port_shutdown,
1567         .activate =             fwtty_port_activate,
1568 };
1569 
1570 static const struct tty_operations fwtty_ops = {
1571         .open =                 fwtty_open,
1572         .close =                fwtty_close,
1573         .hangup =               fwtty_hangup,
1574         .cleanup =              fwtty_cleanup,
1575         .install =              fwtty_install,
1576         .write =                fwtty_write,
1577         .write_room =           fwtty_write_room,
1578         .chars_in_buffer =      fwtty_chars_in_buffer,
1579         .send_xchar =           fwtty_send_xchar,
1580         .throttle =             fwtty_throttle,
1581         .unthrottle =           fwtty_unthrottle,
1582         .ioctl =                fwtty_ioctl,
1583         .set_termios =          fwtty_set_termios,
1584         .break_ctl =            fwtty_break_ctl,
1585         .tiocmget =             fwtty_tiocmget,
1586         .tiocmset =             fwtty_tiocmset,
1587         .get_icount =           fwtty_get_icount,
1588         .proc_fops =            &fwtty_proc_fops,
1589 };
1590 
1591 static const struct tty_operations fwloop_ops = {
1592         .open =                 fwtty_open,
1593         .close =                fwtty_close,
1594         .hangup =               fwtty_hangup,
1595         .cleanup =              fwtty_cleanup,
1596         .install =              fwloop_install,
1597         .write =                fwtty_write,
1598         .write_room =           fwtty_write_room,
1599         .chars_in_buffer =      fwtty_chars_in_buffer,
1600         .send_xchar =           fwtty_send_xchar,
1601         .throttle =             fwtty_throttle,
1602         .unthrottle =           fwtty_unthrottle,
1603         .ioctl =                fwtty_ioctl,
1604         .set_termios =          fwtty_set_termios,
1605         .break_ctl =            fwtty_break_ctl,
1606         .tiocmget =             fwtty_tiocmget,
1607         .tiocmset =             fwtty_tiocmset,
1608         .get_icount =           fwtty_get_icount,
1609 };
1610 
1611 static inline int mgmt_pkt_expected_len(__be16 code)
1612 {
1613         static const struct fwserial_mgmt_pkt pkt;
1614 
1615         switch (be16_to_cpu(code)) {
1616         case FWSC_VIRT_CABLE_PLUG:
1617                 return sizeof(pkt.hdr) + sizeof(pkt.plug_req);
1618 
1619         case FWSC_VIRT_CABLE_PLUG_RSP:  /* | FWSC_RSP_OK */
1620                 return sizeof(pkt.hdr) + sizeof(pkt.plug_rsp);
1621 
1622         case FWSC_VIRT_CABLE_UNPLUG:
1623         case FWSC_VIRT_CABLE_UNPLUG_RSP:
1624         case FWSC_VIRT_CABLE_PLUG_RSP | FWSC_RSP_NACK:
1625         case FWSC_VIRT_CABLE_UNPLUG_RSP | FWSC_RSP_NACK:
1626                 return sizeof(pkt.hdr);
1627 
1628         default:
1629                 return -1;
1630         }
1631 }
1632 
1633 static inline void fill_plug_params(struct virt_plug_params *params,
1634                                     struct fwtty_port *port)
1635 {
1636         u64 status_addr = port->rx_handler.offset;
1637         u64 fifo_addr = port->rx_handler.offset + 4;
1638         size_t fifo_len = port->rx_handler.length - 4;
1639 
1640         params->status_hi = cpu_to_be32(status_addr >> 32);
1641         params->status_lo = cpu_to_be32(status_addr);
1642         params->fifo_hi = cpu_to_be32(fifo_addr >> 32);
1643         params->fifo_lo = cpu_to_be32(fifo_addr);
1644         params->fifo_len = cpu_to_be32(fifo_len);
1645 }
1646 
1647 static inline void fill_plug_req(struct fwserial_mgmt_pkt *pkt,
1648                                  struct fwtty_port *port)
1649 {
1650         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_PLUG);
1651         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1652         fill_plug_params(&pkt->plug_req, port);
1653 }
1654 
1655 static inline void fill_plug_rsp_ok(struct fwserial_mgmt_pkt *pkt,
1656                                     struct fwtty_port *port)
1657 {
1658         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_PLUG_RSP);
1659         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1660         fill_plug_params(&pkt->plug_rsp, port);
1661 }
1662 
1663 static inline void fill_plug_rsp_nack(struct fwserial_mgmt_pkt *pkt)
1664 {
1665         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_PLUG_RSP | FWSC_RSP_NACK);
1666         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1667 }
1668 
1669 static inline void fill_unplug_req(struct fwserial_mgmt_pkt *pkt)
1670 {
1671         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_UNPLUG);
1672         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1673 }
1674 
1675 static inline void fill_unplug_rsp_nack(struct fwserial_mgmt_pkt *pkt)
1676 {
1677         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_UNPLUG_RSP | FWSC_RSP_NACK);
1678         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1679 }
1680 
1681 static inline void fill_unplug_rsp_ok(struct fwserial_mgmt_pkt *pkt)
1682 {
1683         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_UNPLUG_RSP);
1684         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1685 }
1686 
1687 static void fwserial_virt_plug_complete(struct fwtty_peer *peer,
1688                                         struct virt_plug_params *params)
1689 {
1690         struct fwtty_port *port = peer->port;
1691 
1692         peer->status_addr = be32_to_u64(params->status_hi, params->status_lo);
1693         peer->fifo_addr = be32_to_u64(params->fifo_hi, params->fifo_lo);
1694         peer->fifo_len = be32_to_cpu(params->fifo_len);
1695         peer_set_state(peer, FWPS_ATTACHED);
1696 
1697         /* reconfigure tx_fifo optimally for this peer */
1698         spin_lock_bh(&port->lock);
1699         port->max_payload = min(peer->max_payload, peer->fifo_len);
1700         dma_fifo_change_tx_limit(&port->tx_fifo, port->max_payload);
1701         spin_unlock_bh(&peer->port->lock);
1702 
1703         if (port->port.console && port->fwcon_ops->notify != NULL)
1704                 (*port->fwcon_ops->notify)(FWCON_NOTIFY_ATTACH, port->con_data);
1705 
1706         fwtty_info(&peer->unit, "peer (guid:%016llx) connected on %s\n",
1707                    (unsigned long long)peer->guid, dev_name(port->device));
1708 }
1709 
1710 static inline int fwserial_send_mgmt_sync(struct fwtty_peer *peer,
1711                                           struct fwserial_mgmt_pkt *pkt)
1712 {
1713         int generation;
1714         int rcode, tries = 5;
1715 
1716         do {
1717                 generation = peer->generation;
1718                 smp_rmb();
1719 
1720                 rcode = fw_run_transaction(peer->serial->card,
1721                                            TCODE_WRITE_BLOCK_REQUEST,
1722                                            peer->node_id,
1723                                            generation, peer->speed,
1724                                            peer->mgmt_addr,
1725                                            pkt, be16_to_cpu(pkt->hdr.len));
1726                 if (rcode == RCODE_BUSY || rcode == RCODE_SEND_ERROR ||
1727                     rcode == RCODE_GENERATION) {
1728                         fwtty_dbg(&peer->unit, "mgmt write error: %d\n", rcode);
1729                         continue;
1730                 } else {
1731                         break;
1732                 }
1733         } while (--tries > 0);
1734         return rcode;
1735 }
1736 
1737 /**
1738  * fwserial_claim_port - attempt to claim port @ index for peer
1739  *
1740  * Returns ptr to claimed port or error code (as ERR_PTR())
1741  * Can sleep - must be called from process context
1742  */
1743 static struct fwtty_port *fwserial_claim_port(struct fwtty_peer *peer,
1744                                               int index)
1745 {
1746         struct fwtty_port *port;
1747 
1748         if (index < 0 || index >= num_ports)
1749                 return ERR_PTR(-EINVAL);
1750 
1751         /* must guarantee that previous port releases have completed */
1752         synchronize_rcu();
1753 
1754         port = peer->serial->ports[index];
1755         spin_lock_bh(&port->lock);
1756         if (!rcu_access_pointer(port->peer))
1757                 rcu_assign_pointer(port->peer, peer);
1758         else
1759                 port = ERR_PTR(-EBUSY);
1760         spin_unlock_bh(&port->lock);
1761 
1762         return port;
1763 }
1764 
1765 /**
1766  * fwserial_find_port - find avail port and claim for peer
1767  *
1768  * Returns ptr to claimed port or NULL if none avail
1769  * Can sleep - must be called from process context
1770  */
1771 static struct fwtty_port *fwserial_find_port(struct fwtty_peer *peer)
1772 {
1773         struct fwtty_port **ports = peer->serial->ports;
1774         int i;
1775 
1776         /* must guarantee that previous port releases have completed */
1777         synchronize_rcu();
1778 
1779         /* TODO: implement optional GUID-to-specific port # matching */
1780 
1781         /* find an unattached port (but not the loopback port, if present) */
1782         for (i = 0; i < num_ttys; ++i) {
1783                 spin_lock_bh(&ports[i]->lock);
1784                 if (!ports[i]->peer) {
1785                         /* claim port */
1786                         rcu_assign_pointer(ports[i]->peer, peer);
1787                         spin_unlock_bh(&ports[i]->lock);
1788                         return ports[i];
1789                 }
1790                 spin_unlock_bh(&ports[i]->lock);
1791         }
1792         return NULL;
1793 }
1794 
1795 static void fwserial_release_port(struct fwtty_port *port, bool reset)
1796 {
1797         /* drop carrier (and all other line status) */
1798         if (reset)
1799                 fwtty_update_port_status(port, 0);
1800 
1801         spin_lock_bh(&port->lock);
1802 
1803         /* reset dma fifo max transmission size back to S100 */
1804         port->max_payload = link_speed_to_max_payload(SCODE_100);
1805         dma_fifo_change_tx_limit(&port->tx_fifo, port->max_payload);
1806 
1807         RCU_INIT_POINTER(port->peer, NULL);
1808         spin_unlock_bh(&port->lock);
1809 
1810         if (port->port.console && port->fwcon_ops->notify != NULL)
1811                 (*port->fwcon_ops->notify)(FWCON_NOTIFY_DETACH, port->con_data);
1812 }
1813 
1814 static void fwserial_plug_timeout(unsigned long data)
1815 {
1816         struct fwtty_peer *peer = (struct fwtty_peer *)data;
1817         struct fwtty_port *port;
1818 
1819         spin_lock_bh(&peer->lock);
1820         if (peer->state != FWPS_PLUG_PENDING) {
1821                 spin_unlock_bh(&peer->lock);
1822                 return;
1823         }
1824 
1825         port = peer_revert_state(peer);
1826         spin_unlock_bh(&peer->lock);
1827 
1828         if (port)
1829                 fwserial_release_port(port, false);
1830 }
1831 
1832 /**
1833  * fwserial_connect_peer - initiate virtual cable with peer
1834  *
1835  * Returns 0 if VIRT_CABLE_PLUG request was successfully sent,
1836  * otherwise error code.  Must be called from process context.
1837  */
1838 static int fwserial_connect_peer(struct fwtty_peer *peer)
1839 {
1840         struct fwtty_port *port;
1841         struct fwserial_mgmt_pkt *pkt;
1842         int err, rcode;
1843 
1844         pkt = kmalloc(sizeof(*pkt), GFP_KERNEL);
1845         if (!pkt)
1846                 return -ENOMEM;
1847 
1848         port = fwserial_find_port(peer);
1849         if (!port) {
1850                 fwtty_err(&peer->unit, "avail ports in use\n");
1851                 err = -EBUSY;
1852                 goto free_pkt;
1853         }
1854 
1855         spin_lock_bh(&peer->lock);
1856 
1857         /* only initiate VIRT_CABLE_PLUG if peer is currently not attached */
1858         if (peer->state != FWPS_NOT_ATTACHED) {
1859                 err = -EBUSY;
1860                 goto release_port;
1861         }
1862 
1863         peer->port = port;
1864         peer_set_state(peer, FWPS_PLUG_PENDING);
1865 
1866         fill_plug_req(pkt, peer->port);
1867 
1868         setup_timer(&peer->timer, fwserial_plug_timeout, (unsigned long)peer);
1869         mod_timer(&peer->timer, jiffies + VIRT_CABLE_PLUG_TIMEOUT);
1870         spin_unlock_bh(&peer->lock);
1871 
1872         rcode = fwserial_send_mgmt_sync(peer, pkt);
1873 
1874         spin_lock_bh(&peer->lock);
1875         if (peer->state == FWPS_PLUG_PENDING && rcode != RCODE_COMPLETE) {
1876                 if (rcode == RCODE_CONFLICT_ERROR)
1877                         err = -EAGAIN;
1878                 else
1879                         err = -EIO;
1880                 goto cancel_timer;
1881         }
1882         spin_unlock_bh(&peer->lock);
1883 
1884         kfree(pkt);
1885         return 0;
1886 
1887 cancel_timer:
1888         del_timer(&peer->timer);
1889         peer_revert_state(peer);
1890 release_port:
1891         spin_unlock_bh(&peer->lock);
1892         fwserial_release_port(port, false);
1893 free_pkt:
1894         kfree(pkt);
1895         return err;
1896 }
1897 
1898 /**
1899  * fwserial_close_port -
1900  * HUP the tty (if the tty exists) and unregister the tty device.
1901  * Only used by the unit driver upon unit removal to disconnect and
1902  * cleanup all attached ports
1903  *
1904  * The port reference is put by fwtty_cleanup (if a reference was
1905  * ever taken).
1906  */
1907 static void fwserial_close_port(struct tty_driver *driver,
1908                                 struct fwtty_port *port)
1909 {
1910         struct tty_struct *tty;
1911 
1912         mutex_lock(&port->port.mutex);
1913         tty = tty_port_tty_get(&port->port);
1914         if (tty) {
1915                 tty_vhangup(tty);
1916                 tty_kref_put(tty);
1917         }
1918         mutex_unlock(&port->port.mutex);
1919 
1920         if (driver == fwloop_driver)
1921                 tty_unregister_device(driver, loop_idx(port));
1922         else
1923                 tty_unregister_device(driver, port->index);
1924 }
1925 
1926 /**
1927  * fwserial_lookup - finds first fw_serial associated with card
1928  * @card: fw_card to match
1929  *
1930  * NB: caller must be holding fwserial_list_mutex
1931  */
1932 static struct fw_serial *fwserial_lookup(struct fw_card *card)
1933 {
1934         struct fw_serial *serial;
1935 
1936         list_for_each_entry(serial, &fwserial_list, list) {
1937                 if (card == serial->card)
1938                         return serial;
1939         }
1940 
1941         return NULL;
1942 }
1943 
1944 /**
1945  * __fwserial_lookup_rcu - finds first fw_serial associated with card
1946  * @card: fw_card to match
1947  *
1948  * NB: caller must be inside rcu_read_lock() section
1949  */
1950 static struct fw_serial *__fwserial_lookup_rcu(struct fw_card *card)
1951 {
1952         struct fw_serial *serial;
1953 
1954         list_for_each_entry_rcu(serial, &fwserial_list, list) {
1955                 if (card == serial->card)
1956                         return serial;
1957         }
1958 
1959         return NULL;
1960 }
1961 
1962 /**
1963  * __fwserial_peer_by_node_id - finds a peer matching the given generation + id
1964  *
1965  * If a matching peer could not be found for the specified generation/node id,
1966  * this could be because:
1967  * a) the generation has changed and one of the nodes hasn't updated yet
1968  * b) the remote node has created its remote unit device before this
1969  *    local node has created its corresponding remote unit device
1970  * In either case, the remote node should retry
1971  *
1972  * Note: caller must be in rcu_read_lock() section
1973  */
1974 static struct fwtty_peer *__fwserial_peer_by_node_id(struct fw_card *card,
1975                                                      int generation, int id)
1976 {
1977         struct fw_serial *serial;
1978         struct fwtty_peer *peer;
1979 
1980         serial = __fwserial_lookup_rcu(card);
1981         if (!serial) {
1982                 /*
1983                  * Something is very wrong - there should be a matching
1984                  * fw_serial structure for every fw_card. Maybe the remote node
1985                  * has created its remote unit device before this driver has
1986                  * been probed for any unit devices...
1987                  */
1988                 fwtty_err(card, "unknown card (guid %016llx)\n",
1989                           (unsigned long long) card->guid);
1990                 return NULL;
1991         }
1992 
1993         list_for_each_entry_rcu(peer, &serial->peer_list, list) {
1994                 int g = peer->generation;
1995 
1996                 smp_rmb();
1997                 if (generation == g && id == peer->node_id)
1998                         return peer;
1999         }
2000 
2001         return NULL;
2002 }
2003 
2004 #ifdef DEBUG
2005 static void __dump_peer_list(struct fw_card *card)
2006 {
2007         struct fw_serial *serial;
2008         struct fwtty_peer *peer;
2009 
2010         serial = __fwserial_lookup_rcu(card);
2011         if (!serial)
2012                 return;
2013 
2014         list_for_each_entry_rcu(peer, &serial->peer_list, list) {
2015                 int g = peer->generation;
2016 
2017                 smp_rmb();
2018                 fwtty_dbg(card, "peer(%d:%x) guid: %016llx\n",
2019                           g, peer->node_id, (unsigned long long) peer->guid);
2020         }
2021 }
2022 #else
2023 #define __dump_peer_list(s)
2024 #endif
2025 
2026 static void fwserial_auto_connect(struct work_struct *work)
2027 {
2028         struct fwtty_peer *peer = to_peer(to_delayed_work(work), connect);
2029         int err;
2030 
2031         err = fwserial_connect_peer(peer);
2032         if (err == -EAGAIN && ++peer->connect_retries < MAX_CONNECT_RETRIES)
2033                 schedule_delayed_work(&peer->connect, CONNECT_RETRY_DELAY);
2034 }
2035 
2036 static void fwserial_peer_workfn(struct work_struct *work)
2037 {
2038         struct fwtty_peer *peer = to_peer(work, work);
2039 
2040         peer->workfn(work);
2041 }
2042 
2043 /**
2044  * fwserial_add_peer - add a newly probed 'serial' unit device as a 'peer'
2045  * @serial: aggregate representing the specific fw_card to add the peer to
2046  * @unit: 'peer' to create and add to peer_list of serial
2047  *
2048  * Adds a 'peer' (ie, a local or remote 'serial' unit device) to the list of
2049  * peers for a specific fw_card. Optionally, auto-attach this peer to an
2050  * available tty port. This function is called either directly or indirectly
2051  * as a result of a 'serial' unit device being created & probed.
2052  *
2053  * Note: this function is serialized with fwserial_remove_peer() by the
2054  * fwserial_list_mutex held in fwserial_probe().
2055  *
2056  * A 1:1 correspondence between an fw_unit and an fwtty_peer is maintained
2057  * via the dev_set_drvdata() for the device of the fw_unit.
2058  */
2059 static int fwserial_add_peer(struct fw_serial *serial, struct fw_unit *unit)
2060 {
2061         struct device *dev = &unit->device;
2062         struct fw_device  *parent = fw_parent_device(unit);
2063         struct fwtty_peer *peer;
2064         struct fw_csr_iterator ci;
2065         int key, val;
2066         int generation;
2067 
2068         peer = kzalloc(sizeof(*peer), GFP_KERNEL);
2069         if (!peer)
2070                 return -ENOMEM;
2071 
2072         peer_set_state(peer, FWPS_NOT_ATTACHED);
2073 
2074         dev_set_drvdata(dev, peer);
2075         peer->unit = unit;
2076         peer->guid = (u64)parent->config_rom[3] << 32 | parent->config_rom[4];
2077         peer->speed = parent->max_speed;
2078         peer->max_payload = min(device_max_receive(parent),
2079                                 link_speed_to_max_payload(peer->speed));
2080 
2081         generation = parent->generation;
2082         smp_rmb();
2083         peer->node_id = parent->node_id;
2084         smp_wmb();
2085         peer->generation = generation;
2086 
2087         /* retrieve the mgmt bus addr from the unit directory */
2088         fw_csr_iterator_init(&ci, unit->directory);
2089         while (fw_csr_iterator_next(&ci, &key, &val)) {
2090                 if (key == (CSR_OFFSET | CSR_DEPENDENT_INFO)) {
2091                         peer->mgmt_addr = CSR_REGISTER_BASE + 4 * val;
2092                         break;
2093                 }
2094         }
2095         if (peer->mgmt_addr == 0ULL) {
2096                 /*
2097                  * No mgmt address effectively disables VIRT_CABLE_PLUG -
2098                  * this peer will not be able to attach to a remote
2099                  */
2100                 peer_set_state(peer, FWPS_NO_MGMT_ADDR);
2101         }
2102 
2103         spin_lock_init(&peer->lock);
2104         peer->port = NULL;
2105 
2106         init_timer(&peer->timer);
2107         INIT_WORK(&peer->work, fwserial_peer_workfn);
2108         INIT_DELAYED_WORK(&peer->connect, fwserial_auto_connect);
2109 
2110         /* associate peer with specific fw_card */
2111         peer->serial = serial;
2112         list_add_rcu(&peer->list, &serial->peer_list);
2113 
2114         fwtty_info(&peer->unit, "peer added (guid:%016llx)\n",
2115                    (unsigned long long)peer->guid);
2116 
2117         /* identify the local unit & virt cable to loopback port */
2118         if (parent->is_local) {
2119                 serial->self = peer;
2120                 if (create_loop_dev) {
2121                         struct fwtty_port *port;
2122 
2123                         port = fwserial_claim_port(peer, num_ttys);
2124                         if (!IS_ERR(port)) {
2125                                 struct virt_plug_params params;
2126 
2127                                 spin_lock_bh(&peer->lock);
2128                                 peer->port = port;
2129                                 fill_plug_params(&params, port);
2130                                 fwserial_virt_plug_complete(peer, &params);
2131                                 spin_unlock_bh(&peer->lock);
2132 
2133                                 fwtty_write_port_status(port);
2134                         }
2135                 }
2136 
2137         } else if (auto_connect) {
2138                 /* auto-attach to remote units only (if policy allows) */
2139                 schedule_delayed_work(&peer->connect, 1);
2140         }
2141 
2142         return 0;
2143 }
2144 
2145 /**
2146  * fwserial_remove_peer - remove a 'serial' unit device as a 'peer'
2147  *
2148  * Remove a 'peer' from its list of peers. This function is only
2149  * called by fwserial_remove() on bus removal of the unit device.
2150  *
2151  * Note: this function is serialized with fwserial_add_peer() by the
2152  * fwserial_list_mutex held in fwserial_remove().
2153  */
2154 static void fwserial_remove_peer(struct fwtty_peer *peer)
2155 {
2156         struct fwtty_port *port;
2157 
2158         spin_lock_bh(&peer->lock);
2159         peer_set_state(peer, FWPS_GONE);
2160         spin_unlock_bh(&peer->lock);
2161 
2162         cancel_delayed_work_sync(&peer->connect);
2163         cancel_work_sync(&peer->work);
2164 
2165         spin_lock_bh(&peer->lock);
2166         /* if this unit is the local unit, clear link */
2167         if (peer == peer->serial->self)
2168                 peer->serial->self = NULL;
2169 
2170         /* cancel the request timeout timer (if running) */
2171         del_timer(&peer->timer);
2172 
2173         port = peer->port;
2174         peer->port = NULL;
2175 
2176         list_del_rcu(&peer->list);
2177 
2178         fwtty_info(&peer->unit, "peer removed (guid:%016llx)\n",
2179                    (unsigned long long)peer->guid);
2180 
2181         spin_unlock_bh(&peer->lock);
2182 
2183         if (port)
2184                 fwserial_release_port(port, true);
2185 
2186         synchronize_rcu();
2187         kfree(peer);
2188 }
2189 
2190 /**
2191  * fwserial_create - init everything to create TTYs for a specific fw_card
2192  * @unit: fw_unit for first 'serial' unit device probed for this fw_card
2193  *
2194  * This function inits the aggregate structure (an fw_serial instance)
2195  * used to manage the TTY ports registered by a specific fw_card. Also, the
2196  * unit device is added as the first 'peer'.
2197  *
2198  * This unit device may represent a local unit device (as specified by the
2199  * config ROM unit directory) or it may represent a remote unit device
2200  * (as specified by the reading of the remote node's config ROM).
2201  *
2202  * Returns 0 to indicate "ownership" of the unit device, or a negative errno
2203  * value to indicate which error.
2204  */
2205 static int fwserial_create(struct fw_unit *unit)
2206 {
2207         struct fw_device *parent = fw_parent_device(unit);
2208         struct fw_card *card = parent->card;
2209         struct fw_serial *serial;
2210         struct fwtty_port *port;
2211         struct device *tty_dev;
2212         int i, j;
2213         int err;
2214 
2215         serial = kzalloc(sizeof(*serial), GFP_KERNEL);
2216         if (!serial)
2217                 return -ENOMEM;
2218 
2219         kref_init(&serial->kref);
2220         serial->card = card;
2221         INIT_LIST_HEAD(&serial->peer_list);
2222 
2223         for (i = 0; i < num_ports; ++i) {
2224                 port = kzalloc(sizeof(*port), GFP_KERNEL);
2225                 if (!port) {
2226                         err = -ENOMEM;
2227                         goto free_ports;
2228                 }
2229                 tty_port_init(&port->port);
2230                 port->index = FWTTY_INVALID_INDEX;
2231                 port->port.ops = &fwtty_port_ops;
2232                 port->serial = serial;
2233                 tty_buffer_set_limit(&port->port, 128 * 1024);
2234 
2235                 spin_lock_init(&port->lock);
2236                 INIT_DELAYED_WORK(&port->drain, fwtty_drain_tx);
2237                 INIT_DELAYED_WORK(&port->emit_breaks, fwtty_emit_breaks);
2238                 INIT_WORK(&port->hangup, fwtty_do_hangup);
2239                 init_waitqueue_head(&port->wait_tx);
2240                 port->max_payload = link_speed_to_max_payload(SCODE_100);
2241                 dma_fifo_init(&port->tx_fifo);
2242 
2243                 RCU_INIT_POINTER(port->peer, NULL);
2244                 serial->ports[i] = port;
2245 
2246                 /* get unique bus addr region for port's status & recv fifo */
2247                 port->rx_handler.length = FWTTY_PORT_RXFIFO_LEN + 4;
2248                 port->rx_handler.address_callback = fwtty_port_handler;
2249                 port->rx_handler.callback_data = port;
2250                 /*
2251                  * XXX: use custom memory region above cpu physical memory addrs
2252                  * this will ease porting to 64-bit firewire adapters
2253                  */
2254                 err = fw_core_add_address_handler(&port->rx_handler,
2255                                                   &fw_high_memory_region);
2256                 if (err) {
2257                         kfree(port);
2258                         goto free_ports;
2259                 }
2260         }
2261         /* preserve i for error cleanup */
2262 
2263         err = fwtty_ports_add(serial);
2264         if (err) {
2265                 fwtty_err(&unit, "no space in port table\n");
2266                 goto free_ports;
2267         }
2268 
2269         for (j = 0; j < num_ttys; ++j) {
2270                 tty_dev = tty_port_register_device(&serial->ports[j]->port,
2271                                                    fwtty_driver,
2272                                                    serial->ports[j]->index,
2273                                                    card->device);
2274                 if (IS_ERR(tty_dev)) {
2275                         err = PTR_ERR(tty_dev);
2276                         fwtty_err(&unit, "register tty device error (%d)\n",
2277                                   err);
2278                         goto unregister_ttys;
2279                 }
2280 
2281                 serial->ports[j]->device = tty_dev;
2282         }
2283         /* preserve j for error cleanup */
2284 
2285         if (create_loop_dev) {
2286                 struct device *loop_dev;
2287 
2288                 loop_dev = tty_port_register_device(&serial->ports[j]->port,
2289                                                     fwloop_driver,
2290                                                     loop_idx(serial->ports[j]),
2291                                                     card->device);
2292                 if (IS_ERR(loop_dev)) {
2293                         err = PTR_ERR(loop_dev);
2294                         fwtty_err(&unit, "create loop device failed (%d)\n",
2295                                   err);
2296                         goto unregister_ttys;
2297                 }
2298                 serial->ports[j]->device = loop_dev;
2299                 serial->ports[j]->loopback = true;
2300         }
2301 
2302         if (!IS_ERR_OR_NULL(fwserial_debugfs)) {
2303                 serial->debugfs = debugfs_create_dir(dev_name(&unit->device),
2304                                                      fwserial_debugfs);
2305                 if (!IS_ERR_OR_NULL(serial->debugfs)) {
2306                         debugfs_create_file("peers", 0444, serial->debugfs,
2307                                             serial, &fwtty_peers_fops);
2308                         debugfs_create_file("stats", 0444, serial->debugfs,
2309                                             serial, &fwtty_stats_fops);
2310                 }
2311         }
2312 
2313         list_add_rcu(&serial->list, &fwserial_list);
2314 
2315         fwtty_notice(&unit, "TTY over FireWire on device %s (guid %016llx)\n",
2316                      dev_name(card->device), (unsigned long long) card->guid);
2317 
2318         err = fwserial_add_peer(serial, unit);
2319         if (!err)
2320                 return 0;
2321 
2322         fwtty_err(&unit, "unable to add peer unit device (%d)\n", err);
2323 
2324         /* fall-through to error processing */
2325         debugfs_remove_recursive(serial->debugfs);
2326 
2327         list_del_rcu(&serial->list);
2328         if (create_loop_dev)
2329                 tty_unregister_device(fwloop_driver,
2330                                       loop_idx(serial->ports[j]));
2331 unregister_ttys:
2332         for (--j; j >= 0; --j)
2333                 tty_unregister_device(fwtty_driver, serial->ports[j]->index);
2334         kref_put(&serial->kref, fwserial_destroy);
2335         return err;
2336 
2337 free_ports:
2338         for (--i; i >= 0; --i) {
2339                 tty_port_destroy(&serial->ports[i]->port);
2340                 kfree(serial->ports[i]);
2341         }
2342         kfree(serial);
2343         return err;
2344 }
2345 
2346 /**
2347  * fwserial_probe: bus probe function for firewire 'serial' unit devices
2348  *
2349  * A 'serial' unit device is created and probed as a result of:
2350  * - declaring a ieee1394 bus id table for 'devices' matching a fabricated
2351  *   'serial' unit specifier id
2352  * - adding a unit directory to the config ROM(s) for a 'serial' unit
2353  *
2354  * The firewire core registers unit devices by enumerating unit directories
2355  * of a node's config ROM after reading the config ROM when a new node is
2356  * added to the bus topology after a bus reset.
2357  *
2358  * The practical implications of this are:
2359  * - this probe is called for both local and remote nodes that have a 'serial'
2360  *   unit directory in their config ROM (that matches the specifiers in
2361  *   fwserial_id_table).
2362  * - no specific order is enforced for local vs. remote unit devices
2363  *
2364  * This unit driver copes with the lack of specific order in the same way the
2365  * firewire net driver does -- each probe, for either a local or remote unit
2366  * device, is treated as a 'peer' (has a struct fwtty_peer instance) and the
2367  * first peer created for a given fw_card (tracked by the global fwserial_list)
2368  * creates the underlying TTYs (aggregated in a fw_serial instance).
2369  *
2370  * NB: an early attempt to differentiate local & remote unit devices by creating
2371  *     peers only for remote units and fw_serial instances (with their
2372  *     associated TTY devices) only for local units was discarded. Managing
2373  *     the peer lifetimes on device removal proved too complicated.
2374  *
2375  * fwserial_probe/fwserial_remove are effectively serialized by the
2376  * fwserial_list_mutex. This is necessary because the addition of the first peer
2377  * for a given fw_card will trigger the creation of the fw_serial for that
2378  * fw_card, which must not simultaneously contend with the removal of the
2379  * last peer for a given fw_card triggering the destruction of the same
2380  * fw_serial for the same fw_card.
2381  */
2382 static int fwserial_probe(struct fw_unit *unit,
2383                           const struct ieee1394_device_id *id)
2384 {
2385         struct fw_serial *serial;
2386         int err;
2387 
2388         mutex_lock(&fwserial_list_mutex);
2389         serial = fwserial_lookup(fw_parent_device(unit)->card);
2390         if (!serial)
2391                 err = fwserial_create(unit);
2392         else
2393                 err = fwserial_add_peer(serial, unit);
2394         mutex_unlock(&fwserial_list_mutex);
2395         return err;
2396 }
2397 
2398 /**
2399  * fwserial_remove: bus removal function for firewire 'serial' unit devices
2400  *
2401  * The corresponding 'peer' for this unit device is removed from the list of
2402  * peers for the associated fw_serial (which has a 1:1 correspondence with a
2403  * specific fw_card). If this is the last peer being removed, then trigger
2404  * the destruction of the underlying TTYs.
2405  */
2406 static void fwserial_remove(struct fw_unit *unit)
2407 {
2408         struct fwtty_peer *peer = dev_get_drvdata(&unit->device);
2409         struct fw_serial *serial = peer->serial;
2410         int i;
2411 
2412         mutex_lock(&fwserial_list_mutex);
2413         fwserial_remove_peer(peer);
2414 
2415         if (list_empty(&serial->peer_list)) {
2416                 /* unlink from the fwserial_list here */
2417                 list_del_rcu(&serial->list);
2418 
2419                 debugfs_remove_recursive(serial->debugfs);
2420 
2421                 for (i = 0; i < num_ttys; ++i)
2422                         fwserial_close_port(fwtty_driver, serial->ports[i]);
2423                 if (create_loop_dev)
2424                         fwserial_close_port(fwloop_driver, serial->ports[i]);
2425                 kref_put(&serial->kref, fwserial_destroy);
2426         }
2427         mutex_unlock(&fwserial_list_mutex);
2428 }
2429 
2430 /**
2431  * fwserial_update: bus update function for 'firewire' serial unit devices
2432  *
2433  * Updates the new node_id and bus generation for this peer. Note that locking
2434  * is unnecessary; but careful memory barrier usage is important to enforce the
2435  * load and store order of generation & node_id.
2436  *
2437  * The fw-core orders the write of node_id before generation in the parent
2438  * fw_device to ensure that a stale node_id cannot be used with a current
2439  * bus generation. So the generation value must be read before the node_id.
2440  *
2441  * In turn, this orders the write of node_id before generation in the peer to
2442  * also ensure a stale node_id cannot be used with a current bus generation.
2443  */
2444 static void fwserial_update(struct fw_unit *unit)
2445 {
2446         struct fw_device *parent = fw_parent_device(unit);
2447         struct fwtty_peer *peer = dev_get_drvdata(&unit->device);
2448         int generation;
2449 
2450         generation = parent->generation;
2451         smp_rmb();
2452         peer->node_id = parent->node_id;
2453         smp_wmb();
2454         peer->generation = generation;
2455 }
2456 
2457 static const struct ieee1394_device_id fwserial_id_table[] = {
2458         {
2459                 .match_flags  = IEEE1394_MATCH_SPECIFIER_ID |
2460                                 IEEE1394_MATCH_VERSION,
2461                 .specifier_id = LINUX_VENDOR_ID,
2462                 .version      = FWSERIAL_VERSION,
2463         },
2464         { }
2465 };
2466 
2467 static struct fw_driver fwserial_driver = {
2468         .driver = {
2469                 .owner  = THIS_MODULE,
2470                 .name   = KBUILD_MODNAME,
2471                 .bus    = &fw_bus_type,
2472         },
2473         .probe    = fwserial_probe,
2474         .update   = fwserial_update,
2475         .remove   = fwserial_remove,
2476         .id_table = fwserial_id_table,
2477 };
2478 
2479 #define FW_UNIT_SPECIFIER(id)   ((CSR_SPECIFIER_ID << 24) | (id))
2480 #define FW_UNIT_VERSION(ver)    ((CSR_VERSION << 24) | (ver))
2481 #define FW_UNIT_ADDRESS(ofs)    (((CSR_OFFSET | CSR_DEPENDENT_INFO) << 24)  \
2482                                  | (((ofs) - CSR_REGISTER_BASE) >> 2))
2483 /* XXX: config ROM definitons could be improved with semi-automated offset
2484  * and length calculation
2485  */
2486 #define FW_ROM_LEN(quads)       ((quads) << 16)
2487 #define FW_ROM_DESCRIPTOR(ofs)  (((CSR_LEAF | CSR_DESCRIPTOR) << 24) | (ofs))
2488 
2489 struct fwserial_unit_directory_data {
2490         u32     len_crc;
2491         u32     unit_specifier;
2492         u32     unit_sw_version;
2493         u32     unit_addr_offset;
2494         u32     desc1_ofs;
2495         u32     desc1_len_crc;
2496         u32     desc1_data[5];
2497 } __packed;
2498 
2499 static struct fwserial_unit_directory_data fwserial_unit_directory_data = {
2500         .len_crc = FW_ROM_LEN(4),
2501         .unit_specifier = FW_UNIT_SPECIFIER(LINUX_VENDOR_ID),
2502         .unit_sw_version = FW_UNIT_VERSION(FWSERIAL_VERSION),
2503         .desc1_ofs = FW_ROM_DESCRIPTOR(1),
2504         .desc1_len_crc = FW_ROM_LEN(5),
2505         .desc1_data = {
2506                 0x00000000,                     /*   type = text            */
2507                 0x00000000,                     /*   enc = ASCII, lang EN   */
2508                 0x4c696e75,                     /* 'Linux TTY'              */
2509                 0x78205454,
2510                 0x59000000,
2511         },
2512 };
2513 
2514 static struct fw_descriptor fwserial_unit_directory = {
2515         .length = sizeof(fwserial_unit_directory_data) / sizeof(u32),
2516         .key    = (CSR_DIRECTORY | CSR_UNIT) << 24,
2517         .data   = (u32 *)&fwserial_unit_directory_data,
2518 };
2519 
2520 /*
2521  * The management address is in the unit space region but above other known
2522  * address users (to keep wild writes from causing havoc)
2523  */
2524 static const struct fw_address_region fwserial_mgmt_addr_region = {
2525         .start = CSR_REGISTER_BASE + 0x1e0000ULL,
2526         .end = 0x1000000000000ULL,
2527 };
2528 
2529 static struct fw_address_handler fwserial_mgmt_addr_handler;
2530 
2531 /**
2532  * fwserial_handle_plug_req - handle VIRT_CABLE_PLUG request work
2533  * @work: ptr to peer->work
2534  *
2535  * Attempts to complete the VIRT_CABLE_PLUG handshake sequence for this peer.
2536  *
2537  * This checks for a collided request-- ie, that a VIRT_CABLE_PLUG request was
2538  * already sent to this peer. If so, the collision is resolved by comparing
2539  * guid values; the loser sends the plug response.
2540  *
2541  * Note: if an error prevents a response, don't do anything -- the
2542  * remote will timeout its request.
2543  */
2544 static void fwserial_handle_plug_req(struct work_struct *work)
2545 {
2546         struct fwtty_peer *peer = to_peer(work, work);
2547         struct virt_plug_params *plug_req = &peer->work_params.plug_req;
2548         struct fwtty_port *port;
2549         struct fwserial_mgmt_pkt *pkt;
2550         int rcode;
2551 
2552         pkt = kmalloc(sizeof(*pkt), GFP_KERNEL);
2553         if (!pkt)
2554                 return;
2555 
2556         port = fwserial_find_port(peer);
2557 
2558         spin_lock_bh(&peer->lock);
2559 
2560         switch (peer->state) {
2561         case FWPS_NOT_ATTACHED:
2562                 if (!port) {
2563                         fwtty_err(&peer->unit, "no more ports avail\n");
2564                         fill_plug_rsp_nack(pkt);
2565                 } else {
2566                         peer->port = port;
2567                         fill_plug_rsp_ok(pkt, peer->port);
2568                         peer_set_state(peer, FWPS_PLUG_RESPONDING);
2569                         /* don't release claimed port */
2570                         port = NULL;
2571                 }
2572                 break;
2573 
2574         case FWPS_PLUG_PENDING:
2575                 if (peer->serial->card->guid > peer->guid)
2576                         goto cleanup;
2577 
2578                 /* We lost - hijack the already-claimed port and send ok */
2579                 del_timer(&peer->timer);
2580                 fill_plug_rsp_ok(pkt, peer->port);
2581                 peer_set_state(peer, FWPS_PLUG_RESPONDING);
2582                 break;
2583 
2584         default:
2585                 fill_plug_rsp_nack(pkt);
2586         }
2587 
2588         spin_unlock_bh(&peer->lock);
2589         if (port)
2590                 fwserial_release_port(port, false);
2591 
2592         rcode = fwserial_send_mgmt_sync(peer, pkt);
2593 
2594         spin_lock_bh(&peer->lock);
2595         if (peer->state == FWPS_PLUG_RESPONDING) {
2596                 if (rcode == RCODE_COMPLETE) {
2597                         struct fwtty_port *tmp = peer->port;
2598 
2599                         fwserial_virt_plug_complete(peer, plug_req);
2600                         spin_unlock_bh(&peer->lock);
2601 
2602                         fwtty_write_port_status(tmp);
2603                         spin_lock_bh(&peer->lock);
2604                 } else {
2605                         fwtty_err(&peer->unit, "PLUG_RSP error (%d)\n", rcode);
2606                         port = peer_revert_state(peer);
2607                 }
2608         }
2609 cleanup:
2610         spin_unlock_bh(&peer->lock);
2611         if (port)
2612                 fwserial_release_port(port, false);
2613         kfree(pkt);
2614 }
2615 
2616 static void fwserial_handle_unplug_req(struct work_struct *work)
2617 {
2618         struct fwtty_peer *peer = to_peer(work, work);
2619         struct fwtty_port *port = NULL;
2620         struct fwserial_mgmt_pkt *pkt;
2621         int rcode;
2622 
2623         pkt = kmalloc(sizeof(*pkt), GFP_KERNEL);
2624         if (!pkt)
2625                 return;
2626 
2627         spin_lock_bh(&peer->lock);
2628 
2629         switch (peer->state) {
2630         case FWPS_ATTACHED:
2631                 fill_unplug_rsp_ok(pkt);
2632                 peer_set_state(peer, FWPS_UNPLUG_RESPONDING);
2633                 break;
2634 
2635         case FWPS_UNPLUG_PENDING:
2636                 if (peer->serial->card->guid > peer->guid)
2637                         goto cleanup;
2638 
2639                 /* We lost - send unplug rsp */
2640                 del_timer(&peer->timer);
2641                 fill_unplug_rsp_ok(pkt);
2642                 peer_set_state(peer, FWPS_UNPLUG_RESPONDING);
2643                 break;
2644 
2645         default:
2646                 fill_unplug_rsp_nack(pkt);
2647         }
2648 
2649         spin_unlock_bh(&peer->lock);
2650 
2651         rcode = fwserial_send_mgmt_sync(peer, pkt);
2652 
2653         spin_lock_bh(&peer->lock);
2654         if (peer->state == FWPS_UNPLUG_RESPONDING) {
2655                 if (rcode != RCODE_COMPLETE)
2656                         fwtty_err(&peer->unit, "UNPLUG_RSP error (%d)\n",
2657                                   rcode);
2658                 port = peer_revert_state(peer);
2659         }
2660 cleanup:
2661         spin_unlock_bh(&peer->lock);
2662         if (port)
2663                 fwserial_release_port(port, true);
2664         kfree(pkt);
2665 }
2666 
2667 static int fwserial_parse_mgmt_write(struct fwtty_peer *peer,
2668                                      struct fwserial_mgmt_pkt *pkt,
2669                                      unsigned long long addr,
2670                                      size_t len)
2671 {
2672         struct fwtty_port *port = NULL;
2673         bool reset = false;
2674         int rcode;
2675 
2676         if (addr != fwserial_mgmt_addr_handler.offset || len < sizeof(pkt->hdr))
2677                 return RCODE_ADDRESS_ERROR;
2678 
2679         if (len != be16_to_cpu(pkt->hdr.len) ||
2680             len != mgmt_pkt_expected_len(pkt->hdr.code))
2681                 return RCODE_DATA_ERROR;
2682 
2683         spin_lock_bh(&peer->lock);
2684         if (peer->state == FWPS_GONE) {
2685                 /*
2686                  * This should never happen - it would mean that the
2687                  * remote unit that just wrote this transaction was
2688                  * already removed from the bus -- and the removal was
2689                  * processed before we rec'd this transaction
2690                  */
2691                 fwtty_err(&peer->unit, "peer already removed\n");
2692                 spin_unlock_bh(&peer->lock);
2693                 return RCODE_ADDRESS_ERROR;
2694         }
2695 
2696         rcode = RCODE_COMPLETE;
2697 
2698         fwtty_dbg(&peer->unit, "mgmt: hdr.code: %04hx\n", pkt->hdr.code);
2699 
2700         switch (be16_to_cpu(pkt->hdr.code) & FWSC_CODE_MASK) {
2701         case FWSC_VIRT_CABLE_PLUG:
2702                 if (work_pending(&peer->work)) {
2703                         fwtty_err(&peer->unit, "plug req: busy\n");
2704                         rcode = RCODE_CONFLICT_ERROR;
2705 
2706                 } else {
2707                         peer->work_params.plug_req = pkt->plug_req;
2708                         peer->workfn = fwserial_handle_plug_req;
2709                         queue_work(system_unbound_wq, &peer->work);
2710                 }
2711                 break;
2712 
2713         case FWSC_VIRT_CABLE_PLUG_RSP:
2714                 if (peer->state != FWPS_PLUG_PENDING) {
2715                         rcode = RCODE_CONFLICT_ERROR;
2716 
2717                 } else if (be16_to_cpu(pkt->hdr.code) & FWSC_RSP_NACK) {
2718                         fwtty_notice(&peer->unit, "NACK plug rsp\n");
2719                         port = peer_revert_state(peer);
2720 
2721                 } else {
2722                         struct fwtty_port *tmp = peer->port;
2723 
2724                         fwserial_virt_plug_complete(peer, &pkt->plug_rsp);
2725                         spin_unlock_bh(&peer->lock);
2726 
2727                         fwtty_write_port_status(tmp);
2728                         spin_lock_bh(&peer->lock);
2729                 }
2730                 break;
2731 
2732         case FWSC_VIRT_CABLE_UNPLUG:
2733                 if (work_pending(&peer->work)) {
2734                         fwtty_err(&peer->unit, "unplug req: busy\n");
2735                         rcode = RCODE_CONFLICT_ERROR;
2736                 } else {
2737                         peer->workfn = fwserial_handle_unplug_req;
2738                         queue_work(system_unbound_wq, &peer->work);
2739                 }
2740                 break;
2741 
2742         case FWSC_VIRT_CABLE_UNPLUG_RSP:
2743                 if (peer->state != FWPS_UNPLUG_PENDING) {
2744                         rcode = RCODE_CONFLICT_ERROR;
2745                 } else {
2746                         if (be16_to_cpu(pkt->hdr.code) & FWSC_RSP_NACK)
2747                                 fwtty_notice(&peer->unit, "NACK unplug?\n");
2748                         port = peer_revert_state(peer);
2749                         reset = true;
2750                 }
2751                 break;
2752 
2753         default:
2754                 fwtty_err(&peer->unit, "unknown mgmt code %d\n",
2755                           be16_to_cpu(pkt->hdr.code));
2756                 rcode = RCODE_DATA_ERROR;
2757         }
2758         spin_unlock_bh(&peer->lock);
2759 
2760         if (port)
2761                 fwserial_release_port(port, reset);
2762 
2763         return rcode;
2764 }
2765 
2766 /**
2767  * fwserial_mgmt_handler: bus address handler for mgmt requests
2768  * @parameters: fw_address_callback_t as specified by firewire core interface
2769  *
2770  * This handler is responsible for handling virtual cable requests from remotes
2771  * for all cards.
2772  */
2773 static void fwserial_mgmt_handler(struct fw_card *card,
2774                                   struct fw_request *request,
2775                                   int tcode, int destination, int source,
2776                                   int generation,
2777                                   unsigned long long addr,
2778                                   void *data, size_t len,
2779                                   void *callback_data)
2780 {
2781         struct fwserial_mgmt_pkt *pkt = data;
2782         struct fwtty_peer *peer;
2783         int rcode;
2784 
2785         rcu_read_lock();
2786         peer = __fwserial_peer_by_node_id(card, generation, source);
2787         if (!peer) {
2788                 fwtty_dbg(card, "peer(%d:%x) not found\n", generation, source);
2789                 __dump_peer_list(card);
2790                 rcode = RCODE_CONFLICT_ERROR;
2791 
2792         } else {
2793                 switch (tcode) {
2794                 case TCODE_WRITE_BLOCK_REQUEST:
2795                         rcode = fwserial_parse_mgmt_write(peer, pkt, addr, len);
2796                         break;
2797 
2798                 default:
2799                         rcode = RCODE_TYPE_ERROR;
2800                 }
2801         }
2802 
2803         rcu_read_unlock();
2804         fw_send_response(card, request, rcode);
2805 }
2806 
2807 static int __init fwserial_init(void)
2808 {
2809         int err, num_loops = !!(create_loop_dev);
2810 
2811         /* XXX: placeholder for a "firewire" debugfs node */
2812         fwserial_debugfs = debugfs_create_dir(KBUILD_MODNAME, NULL);
2813 
2814         /* num_ttys/num_ports must not be set above the static alloc avail */
2815         if (num_ttys + num_loops > MAX_CARD_PORTS)
2816                 num_ttys = MAX_CARD_PORTS - num_loops;
2817 
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                 goto remove_debugfs;
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 remove_debugfs:
2927         debugfs_remove_recursive(fwserial_debugfs);
2928 
2929         return err;
2930 }
2931 
2932 static void __exit fwserial_exit(void)
2933 {
2934         driver_unregister(&fwserial_driver.driver);
2935         fw_core_remove_descriptor(&fwserial_unit_directory);
2936         fw_core_remove_address_handler(&fwserial_mgmt_addr_handler);
2937         kmem_cache_destroy(fwtty_txn_cache);
2938         if (create_loop_dev) {
2939                 tty_unregister_driver(fwloop_driver);
2940                 put_tty_driver(fwloop_driver);
2941         }
2942         tty_unregister_driver(fwtty_driver);
2943         put_tty_driver(fwtty_driver);
2944         debugfs_remove_recursive(fwserial_debugfs);
2945 }
2946 
2947 module_init(fwserial_init);
2948 module_exit(fwserial_exit);
2949 
2950 MODULE_AUTHOR("Peter Hurley (peter@hurleysoftware.com)");
2951 MODULE_DESCRIPTION("FireWire Serial TTY Driver");
2952 MODULE_LICENSE("GPL");
2953 MODULE_DEVICE_TABLE(ieee1394, fwserial_id_table);
2954 MODULE_PARM_DESC(ttys, "Number of ttys to create for each local firewire node");
2955 MODULE_PARM_DESC(auto, "Auto-connect a tty to each firewire node discovered");
2956 MODULE_PARM_DESC(loop, "Create a loopback device, fwloop<n>, with ttys");
2957 

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