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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, 0644);
 43 module_param_named(auto, auto_connect, bool, 0644);
 44 module_param_named(loop, create_loop_dev, bool, 0644);
 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 int *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 int 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,
307                                      unsigned int status)
308 {
309         unsigned int delta;
310         struct tty_struct *tty;
311 
312         /* simulated LSR/MSR status from remote */
313         status &= ~MCTRL_MASK;
314         delta = (port->mstatus ^ status) & ~MCTRL_MASK;
315         delta &= ~(status & TIOCM_RNG);
316         port->mstatus = status;
317 
318         if (delta & TIOCM_RNG)
319                 ++port->icount.rng;
320         if (delta & TIOCM_DSR)
321                 ++port->icount.dsr;
322         if (delta & TIOCM_CAR)
323                 ++port->icount.dcd;
324         if (delta & TIOCM_CTS)
325                 ++port->icount.cts;
326 
327         fwtty_dbg(port, "status: %x delta: %x\n", status, delta);
328 
329         if (delta & TIOCM_CAR) {
330                 tty = tty_port_tty_get(&port->port);
331                 if (tty && !C_CLOCAL(tty)) {
332                         if (status & TIOCM_CAR)
333                                 wake_up_interruptible(&port->port.open_wait);
334                         else
335                                 schedule_work(&port->hangup);
336                 }
337                 tty_kref_put(tty);
338         }
339 
340         if (delta & TIOCM_CTS) {
341                 tty = tty_port_tty_get(&port->port);
342                 if (tty && C_CRTSCTS(tty)) {
343                         if (tty->hw_stopped) {
344                                 if (status & TIOCM_CTS) {
345                                         tty->hw_stopped = 0;
346                                         if (port->loopback)
347                                                 __fwtty_restart_tx(port);
348                                         else
349                                                 fwtty_restart_tx(port);
350                                 }
351                         } else {
352                                 if (~status & TIOCM_CTS)
353                                         tty->hw_stopped = 1;
354                         }
355                 }
356                 tty_kref_put(tty);
357 
358         } else if (delta & OOB_TX_THROTTLE) {
359                 tty = tty_port_tty_get(&port->port);
360                 if (tty) {
361                         if (tty->hw_stopped) {
362                                 if (~status & OOB_TX_THROTTLE) {
363                                         tty->hw_stopped = 0;
364                                         if (port->loopback)
365                                                 __fwtty_restart_tx(port);
366                                         else
367                                                 fwtty_restart_tx(port);
368                                 }
369                         } else {
370                                 if (status & OOB_TX_THROTTLE)
371                                         tty->hw_stopped = 1;
372                         }
373                 }
374                 tty_kref_put(tty);
375         }
376 
377         if (delta & (UART_LSR_BI << 24)) {
378                 if (status & (UART_LSR_BI << 24)) {
379                         port->break_last = jiffies;
380                         schedule_delayed_work(&port->emit_breaks, 0);
381                 } else {
382                         /* run emit_breaks one last time (if pending) */
383                         mod_delayed_work(system_wq, &port->emit_breaks, 0);
384                 }
385         }
386 
387         if (delta & (TIOCM_DSR | TIOCM_CAR | TIOCM_CTS | TIOCM_RNG))
388                 wake_up_interruptible(&port->port.delta_msr_wait);
389 }
390 
391 /**
392  * __fwtty_port_line_status - generate 'line status' for indicated port
393  *
394  * This function returns a remote 'MSR' state based on the local 'MCR' state,
395  * as if a null modem cable was attached. The actual status is a mangling
396  * of TIOCM_* bits suitable for sending to a peer's status_addr.
397  *
398  * Note: caller must be holding port lock
399  */
400 static unsigned int __fwtty_port_line_status(struct fwtty_port *port)
401 {
402         unsigned int status = 0;
403 
404         /* TODO: add module param to tie RNG to DTR as well */
405 
406         if (port->mctrl & TIOCM_DTR)
407                 status |= TIOCM_DSR | TIOCM_CAR;
408         if (port->mctrl & TIOCM_RTS)
409                 status |= TIOCM_CTS;
410         if (port->mctrl & OOB_RX_THROTTLE)
411                 status |= OOB_TX_THROTTLE;
412         /* emulate BRK as add'l line status */
413         if (port->break_ctl)
414                 status |= UART_LSR_BI << 24;
415 
416         return status;
417 }
418 
419 /**
420  * __fwtty_write_port_status - send the port line status to peer
421  *
422  * Note: caller must be holding the port lock.
423  */
424 static int __fwtty_write_port_status(struct fwtty_port *port)
425 {
426         struct fwtty_peer *peer;
427         int err = -ENOENT;
428         unsigned int status = __fwtty_port_line_status(port);
429 
430         rcu_read_lock();
431         peer = rcu_dereference(port->peer);
432         if (peer) {
433                 err = fwtty_send_data_async(peer, TCODE_WRITE_QUADLET_REQUEST,
434                                             peer->status_addr, &status,
435                                             sizeof(status), NULL, port);
436         }
437         rcu_read_unlock();
438 
439         return err;
440 }
441 
442 /**
443  * fwtty_write_port_status - same as above but locked by port lock
444  */
445 static int fwtty_write_port_status(struct fwtty_port *port)
446 {
447         int err;
448 
449         spin_lock_bh(&port->lock);
450         err = __fwtty_write_port_status(port);
451         spin_unlock_bh(&port->lock);
452         return err;
453 }
454 
455 static void fwtty_throttle_port(struct fwtty_port *port)
456 {
457         struct tty_struct *tty;
458         unsigned int old;
459 
460         tty = tty_port_tty_get(&port->port);
461         if (!tty)
462                 return;
463 
464         spin_lock_bh(&port->lock);
465 
466         old = port->mctrl;
467         port->mctrl |= OOB_RX_THROTTLE;
468         if (C_CRTSCTS(tty))
469                 port->mctrl &= ~TIOCM_RTS;
470         if (~old & OOB_RX_THROTTLE)
471                 __fwtty_write_port_status(port);
472 
473         spin_unlock_bh(&port->lock);
474 
475         tty_kref_put(tty);
476 }
477 
478 /**
479  * fwtty_do_hangup - wait for ldisc to deliver all pending rx; only then hangup
480  *
481  * When the remote has finished tx, and all in-flight rx has been received and
482  * and pushed to the flip buffer, the remote may close its device. This will
483  * drop DTR on the remote which will drop carrier here. Typically, the tty is
484  * hung up when carrier is dropped or lost.
485  *
486  * However, there is a race between the hang up and the line discipline
487  * delivering its data to the reader. A hangup will cause the ldisc to flush
488  * (ie., clear) the read buffer and flip buffer. Because of firewire's
489  * relatively high throughput, the ldisc frequently lags well behind the driver,
490  * resulting in lost data (which has already been received and written to
491  * the flip buffer) when the remote closes its end.
492  *
493  * Unfortunately, since the flip buffer offers no direct method for determining
494  * if it holds data, ensuring the ldisc has delivered all data is problematic.
495  */
496 
497 /* FIXME: drop this workaround when __tty_hangup waits for ldisc completion */
498 static void fwtty_do_hangup(struct work_struct *work)
499 {
500         struct fwtty_port *port = to_port(work, hangup);
501         struct tty_struct *tty;
502 
503         schedule_timeout_uninterruptible(msecs_to_jiffies(50));
504 
505         tty = tty_port_tty_get(&port->port);
506         if (tty)
507                 tty_vhangup(tty);
508         tty_kref_put(tty);
509 }
510 
511 static void fwtty_emit_breaks(struct work_struct *work)
512 {
513         struct fwtty_port *port = to_port(to_delayed_work(work), emit_breaks);
514         static const char buf[16];
515         unsigned long now = jiffies;
516         unsigned long elapsed = now - port->break_last;
517         int n, t, c, brk = 0;
518 
519         /* generate breaks at the line rate (but at least 1) */
520         n = (elapsed * port->cps) / HZ + 1;
521         port->break_last = now;
522 
523         fwtty_dbg(port, "sending %d brks\n", n);
524 
525         while (n) {
526                 t = min(n, 16);
527                 c = tty_insert_flip_string_fixed_flag(&port->port, buf,
528                                                       TTY_BREAK, t);
529                 n -= c;
530                 brk += c;
531                 if (c < t)
532                         break;
533         }
534         tty_flip_buffer_push(&port->port);
535 
536         if (port->mstatus & (UART_LSR_BI << 24))
537                 schedule_delayed_work(&port->emit_breaks, FREQ_BREAKS);
538         port->icount.brk += brk;
539 }
540 
541 static int fwtty_rx(struct fwtty_port *port, unsigned char *data, size_t len)
542 {
543         int c, n = len;
544         unsigned int lsr;
545         int err = 0;
546 
547         fwtty_dbg(port, "%d\n", n);
548         fwtty_profile_data(port->stats.reads, n);
549 
550         if (port->write_only) {
551                 n = 0;
552                 goto out;
553         }
554 
555         /* disregard break status; breaks are generated by emit_breaks work */
556         lsr = (port->mstatus >> 24) & ~UART_LSR_BI;
557 
558         if (port->overrun)
559                 lsr |= UART_LSR_OE;
560 
561         if (lsr & UART_LSR_OE)
562                 ++port->icount.overrun;
563 
564         lsr &= port->status_mask;
565         if (lsr & ~port->ignore_mask & UART_LSR_OE) {
566                 if (!tty_insert_flip_char(&port->port, 0, TTY_OVERRUN)) {
567                         err = -EIO;
568                         goto out;
569                 }
570         }
571         port->overrun = false;
572 
573         if (lsr & port->ignore_mask & ~UART_LSR_OE) {
574                 /* TODO: don't drop SAK and Magic SysRq here */
575                 n = 0;
576                 goto out;
577         }
578 
579         c = tty_insert_flip_string_fixed_flag(&port->port, data, TTY_NORMAL, n);
580         if (c > 0)
581                 tty_flip_buffer_push(&port->port);
582         n -= c;
583 
584         if (n) {
585                 port->overrun = true;
586                 err = -EIO;
587                 fwtty_err_ratelimited(port, "flip buffer overrun\n");
588 
589         } else {
590                 /* throttle the sender if remaining flip buffer space has
591                  * reached high watermark to avoid losing data which may be
592                  * in-flight. Since the AR request context is 32k, that much
593                  * data may have _already_ been acked.
594                  */
595                 if (tty_buffer_space_avail(&port->port) < HIGH_WATERMARK)
596                         fwtty_throttle_port(port);
597         }
598 
599 out:
600         port->icount.rx += len;
601         port->stats.lost += n;
602         return err;
603 }
604 
605 /**
606  * fwtty_port_handler - bus address handler for port reads/writes
607  * @parameters: fw_address_callback_t as specified by firewire core interface
608  *
609  * This handler is responsible for handling inbound read/write dma from remotes.
610  */
611 static void fwtty_port_handler(struct fw_card *card,
612                                struct fw_request *request,
613                                int tcode, int destination, int source,
614                                int generation,
615                                unsigned long long addr,
616                                void *data, size_t len,
617                                void *callback_data)
618 {
619         struct fwtty_port *port = callback_data;
620         struct fwtty_peer *peer;
621         int err;
622         int rcode;
623 
624         /* Only accept rx from the peer virtual-cabled to this port */
625         rcu_read_lock();
626         peer = __fwserial_peer_by_node_id(card, generation, source);
627         rcu_read_unlock();
628         if (!peer || peer != rcu_access_pointer(port->peer)) {
629                 rcode = RCODE_ADDRESS_ERROR;
630                 fwtty_err_ratelimited(port, "ignoring unauthenticated data\n");
631                 goto respond;
632         }
633 
634         switch (tcode) {
635         case TCODE_WRITE_QUADLET_REQUEST:
636                 if (addr != port->rx_handler.offset || len != 4) {
637                         rcode = RCODE_ADDRESS_ERROR;
638                 } else {
639                         fwtty_update_port_status(port, *(unsigned int *)data);
640                         rcode = RCODE_COMPLETE;
641                 }
642                 break;
643 
644         case TCODE_WRITE_BLOCK_REQUEST:
645                 if (addr != port->rx_handler.offset + 4 ||
646                     len > port->rx_handler.length - 4) {
647                         rcode = RCODE_ADDRESS_ERROR;
648                 } else {
649                         err = fwtty_rx(port, data, len);
650                         switch (err) {
651                         case 0:
652                                 rcode = RCODE_COMPLETE;
653                                 break;
654                         case -EIO:
655                                 rcode = RCODE_DATA_ERROR;
656                                 break;
657                         default:
658                                 rcode = RCODE_CONFLICT_ERROR;
659                                 break;
660                         }
661                 }
662                 break;
663 
664         default:
665                 rcode = RCODE_TYPE_ERROR;
666         }
667 
668 respond:
669         fw_send_response(card, request, rcode);
670 }
671 
672 /**
673  * fwtty_tx_complete - callback for tx dma
674  * @data: ignored, has no meaning for write txns
675  * @length: ignored, has no meaning for write txns
676  *
677  * The writer must be woken here if the fifo has been emptied because it
678  * may have slept if chars_in_buffer was != 0
679  */
680 static void fwtty_tx_complete(struct fw_card *card, int rcode,
681                               void *data, size_t length,
682                               struct fwtty_transaction *txn)
683 {
684         struct fwtty_port *port = txn->port;
685         int len;
686 
687         fwtty_dbg(port, "rcode: %d\n", rcode);
688 
689         switch (rcode) {
690         case RCODE_COMPLETE:
691                 spin_lock_bh(&port->lock);
692                 dma_fifo_out_complete(&port->tx_fifo, &txn->dma_pended);
693                 len = dma_fifo_level(&port->tx_fifo);
694                 spin_unlock_bh(&port->lock);
695 
696                 port->icount.tx += txn->dma_pended.len;
697                 break;
698 
699         default:
700                 /* TODO: implement retries */
701                 spin_lock_bh(&port->lock);
702                 dma_fifo_out_complete(&port->tx_fifo, &txn->dma_pended);
703                 len = dma_fifo_level(&port->tx_fifo);
704                 spin_unlock_bh(&port->lock);
705 
706                 port->stats.dropped += txn->dma_pended.len;
707         }
708 
709         if (len < WAKEUP_CHARS)
710                 tty_port_tty_wakeup(&port->port);
711 }
712 
713 static int fwtty_tx(struct fwtty_port *port, bool drain)
714 {
715         struct fwtty_peer *peer;
716         struct fwtty_transaction *txn;
717         struct tty_struct *tty;
718         int n, len;
719 
720         tty = tty_port_tty_get(&port->port);
721         if (!tty)
722                 return -ENOENT;
723 
724         rcu_read_lock();
725         peer = rcu_dereference(port->peer);
726         if (!peer) {
727                 n = -EIO;
728                 goto out;
729         }
730 
731         if (test_and_set_bit(IN_TX, &port->flags)) {
732                 n = -EALREADY;
733                 goto out;
734         }
735 
736         /* try to write as many dma transactions out as possible */
737         n = -EAGAIN;
738         while (!tty->stopped && !tty->hw_stopped &&
739                !test_bit(STOP_TX, &port->flags)) {
740                 txn = kmem_cache_alloc(fwtty_txn_cache, GFP_ATOMIC);
741                 if (!txn) {
742                         n = -ENOMEM;
743                         break;
744                 }
745 
746                 spin_lock_bh(&port->lock);
747                 n = dma_fifo_out_pend(&port->tx_fifo, &txn->dma_pended);
748                 spin_unlock_bh(&port->lock);
749 
750                 fwtty_dbg(port, "out: %u rem: %d\n", txn->dma_pended.len, n);
751 
752                 if (n < 0) {
753                         kmem_cache_free(fwtty_txn_cache, txn);
754                         if (n == -EAGAIN) {
755                                 ++port->stats.tx_stall;
756                         } else if (n == -ENODATA) {
757                                 fwtty_profile_data(port->stats.txns, 0);
758                         } else {
759                                 ++port->stats.fifo_errs;
760                                 fwtty_err_ratelimited(port, "fifo err: %d\n",
761                                                       n);
762                         }
763                         break;
764                 }
765 
766                 fwtty_profile_data(port->stats.txns, txn->dma_pended.len);
767 
768                 fwtty_send_txn_async(peer, txn, TCODE_WRITE_BLOCK_REQUEST,
769                                      peer->fifo_addr, txn->dma_pended.data,
770                                      txn->dma_pended.len, fwtty_tx_complete,
771                                      port);
772                 ++port->stats.sent;
773 
774                 /*
775                  * Stop tx if the 'last view' of the fifo is empty or if
776                  * this is the writer and there's not enough data to bother
777                  */
778                 if (n == 0 || (!drain && n < WRITER_MINIMUM))
779                         break;
780         }
781 
782         if (n >= 0 || n == -EAGAIN || n == -ENOMEM || n == -ENODATA) {
783                 spin_lock_bh(&port->lock);
784                 len = dma_fifo_out_level(&port->tx_fifo);
785                 if (len) {
786                         unsigned long delay = (n == -ENOMEM) ? HZ : 1;
787 
788                         schedule_delayed_work(&port->drain, delay);
789                 }
790                 len = dma_fifo_level(&port->tx_fifo);
791                 spin_unlock_bh(&port->lock);
792 
793                 /* wakeup the writer */
794                 if (drain && len < WAKEUP_CHARS)
795                         tty_wakeup(tty);
796         }
797 
798         clear_bit(IN_TX, &port->flags);
799         wake_up_interruptible(&port->wait_tx);
800 
801 out:
802         rcu_read_unlock();
803         tty_kref_put(tty);
804         return n;
805 }
806 
807 static void fwtty_drain_tx(struct work_struct *work)
808 {
809         struct fwtty_port *port = to_port(to_delayed_work(work), drain);
810 
811         fwtty_tx(port, true);
812 }
813 
814 static void fwtty_write_xchar(struct fwtty_port *port, char ch)
815 {
816         struct fwtty_peer *peer;
817 
818         ++port->stats.xchars;
819 
820         fwtty_dbg(port, "%02x\n", ch);
821 
822         rcu_read_lock();
823         peer = rcu_dereference(port->peer);
824         if (peer) {
825                 fwtty_send_data_async(peer, TCODE_WRITE_BLOCK_REQUEST,
826                                       peer->fifo_addr, &ch, sizeof(ch),
827                                       NULL, port);
828         }
829         rcu_read_unlock();
830 }
831 
832 static struct fwtty_port *fwtty_port_get(unsigned int index)
833 {
834         struct fwtty_port *port;
835 
836         if (index >= MAX_TOTAL_PORTS)
837                 return NULL;
838 
839         mutex_lock(&port_table_lock);
840         port = port_table[index];
841         if (port)
842                 kref_get(&port->serial->kref);
843         mutex_unlock(&port_table_lock);
844         return port;
845 }
846 
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 int set_termios(struct fwtty_port *port, struct tty_struct *tty)
939 {
940         unsigned int 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 int 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 int 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 int 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) || !tty_throttled(tty))
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 int 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,
1385                           unsigned int set, unsigned int clear)
1386 {
1387         struct fwtty_port *port = tty->driver_data;
1388 
1389         fwtty_dbg(port, "set: %x clear: %x\n", set, clear);
1390 
1391         /* TODO: simulate loopback if TIOCM_LOOP set */
1392 
1393         spin_lock_bh(&port->lock);
1394         port->mctrl &= ~(clear & MCTRL_MASK & 0xffff);
1395         port->mctrl |= set & MCTRL_MASK & 0xffff;
1396         __fwtty_write_port_status(port);
1397         spin_unlock_bh(&port->lock);
1398         return 0;
1399 }
1400 
1401 static int fwtty_get_icount(struct tty_struct *tty,
1402                             struct serial_icounter_struct *icount)
1403 {
1404         struct fwtty_port *port = tty->driver_data;
1405         struct stats stats;
1406 
1407         memcpy(&stats, &port->stats, sizeof(stats));
1408         if (port->port.console)
1409                 (*port->fwcon_ops->stats)(&stats, port->con_data);
1410 
1411         icount->cts = port->icount.cts;
1412         icount->dsr = port->icount.dsr;
1413         icount->rng = port->icount.rng;
1414         icount->dcd = port->icount.dcd;
1415         icount->rx  = port->icount.rx;
1416         icount->tx  = port->icount.tx + stats.xchars;
1417         icount->frame   = port->icount.frame;
1418         icount->overrun = port->icount.overrun;
1419         icount->parity  = port->icount.parity;
1420         icount->brk     = port->icount.brk;
1421         icount->buf_overrun = port->icount.overrun;
1422         return 0;
1423 }
1424 
1425 static void fwtty_proc_show_port(struct seq_file *m, struct fwtty_port *port)
1426 {
1427         struct stats stats;
1428 
1429         memcpy(&stats, &port->stats, sizeof(stats));
1430         if (port->port.console)
1431                 (*port->fwcon_ops->stats)(&stats, port->con_data);
1432 
1433         seq_printf(m, " addr:%012llx tx:%d rx:%d", port->rx_handler.offset,
1434                    port->icount.tx + stats.xchars, port->icount.rx);
1435         seq_printf(m, " cts:%d dsr:%d rng:%d dcd:%d", port->icount.cts,
1436                    port->icount.dsr, port->icount.rng, port->icount.dcd);
1437         seq_printf(m, " fe:%d oe:%d pe:%d brk:%d", port->icount.frame,
1438                    port->icount.overrun, port->icount.parity, port->icount.brk);
1439 }
1440 
1441 static void fwtty_debugfs_show_port(struct seq_file *m, struct fwtty_port *port)
1442 {
1443         struct stats stats;
1444 
1445         memcpy(&stats, &port->stats, sizeof(stats));
1446         if (port->port.console)
1447                 (*port->fwcon_ops->stats)(&stats, port->con_data);
1448 
1449         seq_printf(m, " dr:%d st:%d err:%d lost:%d", stats.dropped,
1450                    stats.tx_stall, stats.fifo_errs, stats.lost);
1451         seq_printf(m, " pkts:%d thr:%d", stats.sent, stats.throttled);
1452 
1453         if (port->port.console) {
1454                 seq_puts(m, "\n    ");
1455                 (*port->fwcon_ops->proc_show)(m, port->con_data);
1456         }
1457 
1458         fwtty_dump_profile(m, &port->stats);
1459 }
1460 
1461 static void fwtty_debugfs_show_peer(struct seq_file *m, struct fwtty_peer *peer)
1462 {
1463         int generation = peer->generation;
1464 
1465         smp_rmb();
1466         seq_printf(m, " %s:", dev_name(&peer->unit->device));
1467         seq_printf(m, " node:%04x gen:%d", peer->node_id, generation);
1468         seq_printf(m, " sp:%d max:%d guid:%016llx", peer->speed,
1469                    peer->max_payload, (unsigned long long)peer->guid);
1470         seq_printf(m, " mgmt:%012llx", (unsigned long long)peer->mgmt_addr);
1471         seq_printf(m, " addr:%012llx", (unsigned long long)peer->status_addr);
1472         seq_putc(m, '\n');
1473 }
1474 
1475 static int fwtty_proc_show(struct seq_file *m, void *v)
1476 {
1477         struct fwtty_port *port;
1478         int i;
1479 
1480         seq_puts(m, "fwserinfo: 1.0 driver: 1.0\n");
1481         for (i = 0; i < MAX_TOTAL_PORTS && (port = fwtty_port_get(i)); ++i) {
1482                 seq_printf(m, "%2d:", i);
1483                 if (capable(CAP_SYS_ADMIN))
1484                         fwtty_proc_show_port(m, port);
1485                 fwtty_port_put(port);
1486                 seq_puts(m, "\n");
1487         }
1488         return 0;
1489 }
1490 
1491 static int fwtty_debugfs_stats_show(struct seq_file *m, void *v)
1492 {
1493         struct fw_serial *serial = m->private;
1494         struct fwtty_port *port;
1495         int i;
1496 
1497         for (i = 0; i < num_ports; ++i) {
1498                 port = fwtty_port_get(serial->ports[i]->index);
1499                 if (port) {
1500                         seq_printf(m, "%2d:", port->index);
1501                         fwtty_proc_show_port(m, port);
1502                         fwtty_debugfs_show_port(m, port);
1503                         fwtty_port_put(port);
1504                         seq_puts(m, "\n");
1505                 }
1506         }
1507         return 0;
1508 }
1509 
1510 static int fwtty_debugfs_peers_show(struct seq_file *m, void *v)
1511 {
1512         struct fw_serial *serial = m->private;
1513         struct fwtty_peer *peer;
1514 
1515         rcu_read_lock();
1516         seq_printf(m, "card: %s  guid: %016llx\n",
1517                    dev_name(serial->card->device),
1518                    (unsigned long long)serial->card->guid);
1519         list_for_each_entry_rcu(peer, &serial->peer_list, list)
1520                 fwtty_debugfs_show_peer(m, peer);
1521         rcu_read_unlock();
1522         return 0;
1523 }
1524 
1525 static int fwtty_proc_open(struct inode *inode, struct file *fp)
1526 {
1527         return single_open(fp, fwtty_proc_show, NULL);
1528 }
1529 
1530 static int fwtty_stats_open(struct inode *inode, struct file *fp)
1531 {
1532         return single_open(fp, fwtty_debugfs_stats_show, inode->i_private);
1533 }
1534 
1535 static int fwtty_peers_open(struct inode *inode, struct file *fp)
1536 {
1537         return single_open(fp, fwtty_debugfs_peers_show, inode->i_private);
1538 }
1539 
1540 static const struct file_operations fwtty_stats_fops = {
1541         .owner =        THIS_MODULE,
1542         .open =         fwtty_stats_open,
1543         .read =         seq_read,
1544         .llseek =       seq_lseek,
1545         .release =      single_release,
1546 };
1547 
1548 static const struct file_operations fwtty_peers_fops = {
1549         .owner =        THIS_MODULE,
1550         .open =         fwtty_peers_open,
1551         .read =         seq_read,
1552         .llseek =       seq_lseek,
1553         .release =      single_release,
1554 };
1555 
1556 static const struct file_operations fwtty_proc_fops = {
1557         .owner =        THIS_MODULE,
1558         .open =         fwtty_proc_open,
1559         .read =         seq_read,
1560         .llseek =       seq_lseek,
1561         .release =      single_release,
1562 };
1563 
1564 static const struct tty_port_operations fwtty_port_ops = {
1565         .dtr_rts =              fwtty_port_dtr_rts,
1566         .carrier_raised =       fwtty_port_carrier_raised,
1567         .shutdown =             fwtty_port_shutdown,
1568         .activate =             fwtty_port_activate,
1569 };
1570 
1571 static const struct tty_operations fwtty_ops = {
1572         .open =                 fwtty_open,
1573         .close =                fwtty_close,
1574         .hangup =               fwtty_hangup,
1575         .cleanup =              fwtty_cleanup,
1576         .install =              fwtty_install,
1577         .write =                fwtty_write,
1578         .write_room =           fwtty_write_room,
1579         .chars_in_buffer =      fwtty_chars_in_buffer,
1580         .send_xchar =           fwtty_send_xchar,
1581         .throttle =             fwtty_throttle,
1582         .unthrottle =           fwtty_unthrottle,
1583         .ioctl =                fwtty_ioctl,
1584         .set_termios =          fwtty_set_termios,
1585         .break_ctl =            fwtty_break_ctl,
1586         .tiocmget =             fwtty_tiocmget,
1587         .tiocmset =             fwtty_tiocmset,
1588         .get_icount =           fwtty_get_icount,
1589         .proc_fops =            &fwtty_proc_fops,
1590 };
1591 
1592 static const struct tty_operations fwloop_ops = {
1593         .open =                 fwtty_open,
1594         .close =                fwtty_close,
1595         .hangup =               fwtty_hangup,
1596         .cleanup =              fwtty_cleanup,
1597         .install =              fwloop_install,
1598         .write =                fwtty_write,
1599         .write_room =           fwtty_write_room,
1600         .chars_in_buffer =      fwtty_chars_in_buffer,
1601         .send_xchar =           fwtty_send_xchar,
1602         .throttle =             fwtty_throttle,
1603         .unthrottle =           fwtty_unthrottle,
1604         .ioctl =                fwtty_ioctl,
1605         .set_termios =          fwtty_set_termios,
1606         .break_ctl =            fwtty_break_ctl,
1607         .tiocmget =             fwtty_tiocmget,
1608         .tiocmset =             fwtty_tiocmset,
1609         .get_icount =           fwtty_get_icount,
1610 };
1611 
1612 static inline int mgmt_pkt_expected_len(__be16 code)
1613 {
1614         static const struct fwserial_mgmt_pkt pkt;
1615 
1616         switch (be16_to_cpu(code)) {
1617         case FWSC_VIRT_CABLE_PLUG:
1618                 return sizeof(pkt.hdr) + sizeof(pkt.plug_req);
1619 
1620         case FWSC_VIRT_CABLE_PLUG_RSP:  /* | FWSC_RSP_OK */
1621                 return sizeof(pkt.hdr) + sizeof(pkt.plug_rsp);
1622 
1623         case FWSC_VIRT_CABLE_UNPLUG:
1624         case FWSC_VIRT_CABLE_UNPLUG_RSP:
1625         case FWSC_VIRT_CABLE_PLUG_RSP | FWSC_RSP_NACK:
1626         case FWSC_VIRT_CABLE_UNPLUG_RSP | FWSC_RSP_NACK:
1627                 return sizeof(pkt.hdr);
1628 
1629         default:
1630                 return -1;
1631         }
1632 }
1633 
1634 static inline void fill_plug_params(struct virt_plug_params *params,
1635                                     struct fwtty_port *port)
1636 {
1637         u64 status_addr = port->rx_handler.offset;
1638         u64 fifo_addr = port->rx_handler.offset + 4;
1639         size_t fifo_len = port->rx_handler.length - 4;
1640 
1641         params->status_hi = cpu_to_be32(status_addr >> 32);
1642         params->status_lo = cpu_to_be32(status_addr);
1643         params->fifo_hi = cpu_to_be32(fifo_addr >> 32);
1644         params->fifo_lo = cpu_to_be32(fifo_addr);
1645         params->fifo_len = cpu_to_be32(fifo_len);
1646 }
1647 
1648 static inline void fill_plug_req(struct fwserial_mgmt_pkt *pkt,
1649                                  struct fwtty_port *port)
1650 {
1651         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_PLUG);
1652         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1653         fill_plug_params(&pkt->plug_req, port);
1654 }
1655 
1656 static inline void fill_plug_rsp_ok(struct fwserial_mgmt_pkt *pkt,
1657                                     struct fwtty_port *port)
1658 {
1659         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_PLUG_RSP);
1660         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1661         fill_plug_params(&pkt->plug_rsp, port);
1662 }
1663 
1664 static inline void fill_plug_rsp_nack(struct fwserial_mgmt_pkt *pkt)
1665 {
1666         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_PLUG_RSP | FWSC_RSP_NACK);
1667         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1668 }
1669 
1670 static inline void fill_unplug_rsp_nack(struct fwserial_mgmt_pkt *pkt)
1671 {
1672         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_UNPLUG_RSP | FWSC_RSP_NACK);
1673         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1674 }
1675 
1676 static inline void fill_unplug_rsp_ok(struct fwserial_mgmt_pkt *pkt)
1677 {
1678         pkt->hdr.code = cpu_to_be16(FWSC_VIRT_CABLE_UNPLUG_RSP);
1679         pkt->hdr.len = cpu_to_be16(mgmt_pkt_expected_len(pkt->hdr.code));
1680 }
1681 
1682 static void fwserial_virt_plug_complete(struct fwtty_peer *peer,
1683                                         struct virt_plug_params *params)
1684 {
1685         struct fwtty_port *port = peer->port;
1686 
1687         peer->status_addr = be32_to_u64(params->status_hi, params->status_lo);
1688         peer->fifo_addr = be32_to_u64(params->fifo_hi, params->fifo_lo);
1689         peer->fifo_len = be32_to_cpu(params->fifo_len);
1690         peer_set_state(peer, FWPS_ATTACHED);
1691 
1692         /* reconfigure tx_fifo optimally for this peer */
1693         spin_lock_bh(&port->lock);
1694         port->max_payload = min(peer->max_payload, peer->fifo_len);
1695         dma_fifo_change_tx_limit(&port->tx_fifo, port->max_payload);
1696         spin_unlock_bh(&peer->port->lock);
1697 
1698         if (port->port.console && port->fwcon_ops->notify)
1699                 (*port->fwcon_ops->notify)(FWCON_NOTIFY_ATTACH, port->con_data);
1700 
1701         fwtty_info(&peer->unit, "peer (guid:%016llx) connected on %s\n",
1702                    (unsigned long long)peer->guid, dev_name(port->device));
1703 }
1704 
1705 static inline int fwserial_send_mgmt_sync(struct fwtty_peer *peer,
1706                                           struct fwserial_mgmt_pkt *pkt)
1707 {
1708         int generation;
1709         int rcode, tries = 5;
1710 
1711         do {
1712                 generation = peer->generation;
1713                 smp_rmb();
1714 
1715                 rcode = fw_run_transaction(peer->serial->card,
1716                                            TCODE_WRITE_BLOCK_REQUEST,
1717                                            peer->node_id,
1718                                            generation, peer->speed,
1719                                            peer->mgmt_addr,
1720                                            pkt, be16_to_cpu(pkt->hdr.len));
1721                 if (rcode == RCODE_BUSY || rcode == RCODE_SEND_ERROR ||
1722                     rcode == RCODE_GENERATION) {
1723                         fwtty_dbg(&peer->unit, "mgmt write error: %d\n", rcode);
1724                         continue;
1725                 } else {
1726                         break;
1727                 }
1728         } while (--tries > 0);
1729         return rcode;
1730 }
1731 
1732 /**
1733  * fwserial_claim_port - attempt to claim port @ index for peer
1734  *
1735  * Returns ptr to claimed port or error code (as ERR_PTR())
1736  * Can sleep - must be called from process context
1737  */
1738 static struct fwtty_port *fwserial_claim_port(struct fwtty_peer *peer,
1739                                               int index)
1740 {
1741         struct fwtty_port *port;
1742 
1743         if (index < 0 || index >= num_ports)
1744                 return ERR_PTR(-EINVAL);
1745 
1746         /* must guarantee that previous port releases have completed */
1747         synchronize_rcu();
1748 
1749         port = peer->serial->ports[index];
1750         spin_lock_bh(&port->lock);
1751         if (!rcu_access_pointer(port->peer))
1752                 rcu_assign_pointer(port->peer, peer);
1753         else
1754                 port = ERR_PTR(-EBUSY);
1755         spin_unlock_bh(&port->lock);
1756 
1757         return port;
1758 }
1759 
1760 /**
1761  * fwserial_find_port - find avail port and claim for peer
1762  *
1763  * Returns ptr to claimed port or NULL if none avail
1764  * Can sleep - must be called from process context
1765  */
1766 static struct fwtty_port *fwserial_find_port(struct fwtty_peer *peer)
1767 {
1768         struct fwtty_port **ports = peer->serial->ports;
1769         int i;
1770 
1771         /* must guarantee that previous port releases have completed */
1772         synchronize_rcu();
1773 
1774         /* TODO: implement optional GUID-to-specific port # matching */
1775 
1776         /* find an unattached port (but not the loopback port, if present) */
1777         for (i = 0; i < num_ttys; ++i) {
1778                 spin_lock_bh(&ports[i]->lock);
1779                 if (!ports[i]->peer) {
1780                         /* claim port */
1781                         rcu_assign_pointer(ports[i]->peer, peer);
1782                         spin_unlock_bh(&ports[i]->lock);
1783                         return ports[i];
1784                 }
1785                 spin_unlock_bh(&ports[i]->lock);
1786         }
1787         return NULL;
1788 }
1789 
1790 static void fwserial_release_port(struct fwtty_port *port, bool reset)
1791 {
1792         /* drop carrier (and all other line status) */
1793         if (reset)
1794                 fwtty_update_port_status(port, 0);
1795 
1796         spin_lock_bh(&port->lock);
1797 
1798         /* reset dma fifo max transmission size back to S100 */
1799         port->max_payload = link_speed_to_max_payload(SCODE_100);
1800         dma_fifo_change_tx_limit(&port->tx_fifo, port->max_payload);
1801 
1802         RCU_INIT_POINTER(port->peer, NULL);
1803         spin_unlock_bh(&port->lock);
1804 
1805         if (port->port.console && port->fwcon_ops->notify)
1806                 (*port->fwcon_ops->notify)(FWCON_NOTIFY_DETACH, port->con_data);
1807 }
1808 
1809 static void fwserial_plug_timeout(unsigned long data)
1810 {
1811         struct fwtty_peer *peer = (struct fwtty_peer *)data;
1812         struct fwtty_port *port;
1813 
1814         spin_lock_bh(&peer->lock);
1815         if (peer->state != FWPS_PLUG_PENDING) {
1816                 spin_unlock_bh(&peer->lock);
1817                 return;
1818         }
1819 
1820         port = peer_revert_state(peer);
1821         spin_unlock_bh(&peer->lock);
1822 
1823         if (port)
1824                 fwserial_release_port(port, false);
1825 }
1826 
1827 /**
1828  * fwserial_connect_peer - initiate virtual cable with peer
1829  *
1830  * Returns 0 if VIRT_CABLE_PLUG request was successfully sent,
1831  * otherwise error code.  Must be called from process context.
1832  */
1833 static int fwserial_connect_peer(struct fwtty_peer *peer)
1834 {
1835         struct fwtty_port *port;
1836         struct fwserial_mgmt_pkt *pkt;
1837         int err, rcode;
1838 
1839         pkt = kmalloc(sizeof(*pkt), GFP_KERNEL);
1840         if (!pkt)
1841                 return -ENOMEM;
1842 
1843         port = fwserial_find_port(peer);
1844         if (!port) {
1845                 fwtty_err(&peer->unit, "avail ports in use\n");
1846                 err = -EBUSY;
1847                 goto free_pkt;
1848         }
1849 
1850         spin_lock_bh(&peer->lock);
1851 
1852         /* only initiate VIRT_CABLE_PLUG if peer is currently not attached */
1853         if (peer->state != FWPS_NOT_ATTACHED) {
1854                 err = -EBUSY;
1855                 goto release_port;
1856         }
1857 
1858         peer->port = port;
1859         peer_set_state(peer, FWPS_PLUG_PENDING);
1860 
1861         fill_plug_req(pkt, peer->port);
1862 
1863         setup_timer(&peer->timer, fwserial_plug_timeout, (unsigned long)peer);
1864         mod_timer(&peer->timer, jiffies + VIRT_CABLE_PLUG_TIMEOUT);
1865         spin_unlock_bh(&peer->lock);
1866 
1867         rcode = fwserial_send_mgmt_sync(peer, pkt);
1868 
1869         spin_lock_bh(&peer->lock);
1870         if (peer->state == FWPS_PLUG_PENDING && rcode != RCODE_COMPLETE) {
1871                 if (rcode == RCODE_CONFLICT_ERROR)
1872                         err = -EAGAIN;
1873                 else
1874                         err = -EIO;
1875                 goto cancel_timer;
1876         }
1877         spin_unlock_bh(&peer->lock);
1878 
1879         kfree(pkt);
1880         return 0;
1881 
1882 cancel_timer:
1883         del_timer(&peer->timer);
1884         peer_revert_state(peer);
1885 release_port:
1886         spin_unlock_bh(&peer->lock);
1887         fwserial_release_port(port, false);
1888 free_pkt:
1889         kfree(pkt);
1890         return err;
1891 }
1892 
1893 /**
1894  * fwserial_close_port -
1895  * HUP the tty (if the tty exists) and unregister the tty device.
1896  * Only used by the unit driver upon unit removal to disconnect and
1897  * cleanup all attached ports
1898  *
1899  * The port reference is put by fwtty_cleanup (if a reference was
1900  * ever taken).
1901  */
1902 static void fwserial_close_port(struct tty_driver *driver,
1903                                 struct fwtty_port *port)
1904 {
1905         struct tty_struct *tty;
1906 
1907         mutex_lock(&port->port.mutex);
1908         tty = tty_port_tty_get(&port->port);
1909         if (tty) {
1910                 tty_vhangup(tty);
1911                 tty_kref_put(tty);
1912         }
1913         mutex_unlock(&port->port.mutex);
1914 
1915         if (driver == fwloop_driver)
1916                 tty_unregister_device(driver, loop_idx(port));
1917         else
1918                 tty_unregister_device(driver, port->index);
1919 }
1920 
1921 /**
1922  * fwserial_lookup - finds first fw_serial associated with card
1923  * @card: fw_card to match
1924  *
1925  * NB: caller must be holding fwserial_list_mutex
1926  */
1927 static struct fw_serial *fwserial_lookup(struct fw_card *card)
1928 {
1929         struct fw_serial *serial;
1930 
1931         list_for_each_entry(serial, &fwserial_list, list) {
1932                 if (card == serial->card)
1933                         return serial;
1934         }
1935 
1936         return NULL;
1937 }
1938 
1939 /**
1940  * __fwserial_lookup_rcu - finds first fw_serial associated with card
1941  * @card: fw_card to match
1942  *
1943  * NB: caller must be inside rcu_read_lock() section
1944  */
1945 static struct fw_serial *__fwserial_lookup_rcu(struct fw_card *card)
1946 {
1947         struct fw_serial *serial;
1948 
1949         list_for_each_entry_rcu(serial, &fwserial_list, list) {
1950                 if (card == serial->card)
1951                         return serial;
1952         }
1953 
1954         return NULL;
1955 }
1956 
1957 /**
1958  * __fwserial_peer_by_node_id - finds a peer matching the given generation + id
1959  *
1960  * If a matching peer could not be found for the specified generation/node id,
1961  * this could be because:
1962  * a) the generation has changed and one of the nodes hasn't updated yet
1963  * b) the remote node has created its remote unit device before this
1964  *    local node has created its corresponding remote unit device
1965  * In either case, the remote node should retry
1966  *
1967  * Note: caller must be in rcu_read_lock() section
1968  */
1969 static struct fwtty_peer *__fwserial_peer_by_node_id(struct fw_card *card,
1970                                                      int generation, int id)
1971 {
1972         struct fw_serial *serial;
1973         struct fwtty_peer *peer;
1974 
1975         serial = __fwserial_lookup_rcu(card);
1976         if (!serial) {
1977                 /*
1978                  * Something is very wrong - there should be a matching
1979                  * fw_serial structure for every fw_card. Maybe the remote node
1980                  * has created its remote unit device before this driver has
1981                  * been probed for any unit devices...
1982                  */
1983                 fwtty_err(card, "unknown card (guid %016llx)\n",
1984                           (unsigned long long)card->guid);
1985                 return NULL;
1986         }
1987 
1988         list_for_each_entry_rcu(peer, &serial->peer_list, list) {
1989                 int g = peer->generation;
1990 
1991                 smp_rmb();
1992                 if (generation == g && id == peer->node_id)
1993                         return peer;
1994         }
1995 
1996         return NULL;
1997 }
1998 
1999 #ifdef DEBUG
2000 static void __dump_peer_list(struct fw_card *card)
2001 {
2002         struct fw_serial *serial;
2003         struct fwtty_peer *peer;
2004 
2005         serial = __fwserial_lookup_rcu(card);
2006         if (!serial)
2007                 return;
2008 
2009         list_for_each_entry_rcu(peer, &serial->peer_list, list) {
2010                 int g = peer->generation;
2011 
2012                 smp_rmb();
2013                 fwtty_dbg(card, "peer(%d:%x) guid: %016llx\n",
2014                           g, peer->node_id, (unsigned long long)peer->guid);
2015         }
2016 }
2017 #else
2018 #define __dump_peer_list(s)
2019 #endif
2020 
2021 static void fwserial_auto_connect(struct work_struct *work)
2022 {
2023         struct fwtty_peer *peer = to_peer(to_delayed_work(work), connect);
2024         int err;
2025 
2026         err = fwserial_connect_peer(peer);
2027         if (err == -EAGAIN && ++peer->connect_retries < MAX_CONNECT_RETRIES)
2028                 schedule_delayed_work(&peer->connect, CONNECT_RETRY_DELAY);
2029 }
2030 
2031 static void fwserial_peer_workfn(struct work_struct *work)
2032 {
2033         struct fwtty_peer *peer = to_peer(work, work);
2034 
2035         peer->workfn(work);
2036 }
2037 
2038 /**
2039  * fwserial_add_peer - add a newly probed 'serial' unit device as a 'peer'
2040  * @serial: aggregate representing the specific fw_card to add the peer to
2041  * @unit: 'peer' to create and add to peer_list of serial
2042  *
2043  * Adds a 'peer' (ie, a local or remote 'serial' unit device) to the list of
2044  * peers for a specific fw_card. Optionally, auto-attach this peer to an
2045  * available tty port. This function is called either directly or indirectly
2046  * as a result of a 'serial' unit device being created & probed.
2047  *
2048  * Note: this function is serialized with fwserial_remove_peer() by the
2049  * fwserial_list_mutex held in fwserial_probe().
2050  *
2051  * A 1:1 correspondence between an fw_unit and an fwtty_peer is maintained
2052  * via the dev_set_drvdata() for the device of the fw_unit.
2053  */
2054 static int fwserial_add_peer(struct fw_serial *serial, struct fw_unit *unit)
2055 {
2056         struct device *dev = &unit->device;
2057         struct fw_device  *parent = fw_parent_device(unit);
2058         struct fwtty_peer *peer;
2059         struct fw_csr_iterator ci;
2060         int key, val;
2061         int generation;
2062 
2063         peer = kzalloc(sizeof(*peer), GFP_KERNEL);
2064         if (!peer)
2065                 return -ENOMEM;
2066 
2067         peer_set_state(peer, FWPS_NOT_ATTACHED);
2068 
2069         dev_set_drvdata(dev, peer);
2070         peer->unit = unit;
2071         peer->guid = (u64)parent->config_rom[3] << 32 | parent->config_rom[4];
2072         peer->speed = parent->max_speed;
2073         peer->max_payload = min(device_max_receive(parent),
2074                                 link_speed_to_max_payload(peer->speed));
2075 
2076         generation = parent->generation;
2077         smp_rmb();
2078         peer->node_id = parent->node_id;
2079         smp_wmb();
2080         peer->generation = generation;
2081 
2082         /* retrieve the mgmt bus addr from the unit directory */
2083         fw_csr_iterator_init(&ci, unit->directory);
2084         while (fw_csr_iterator_next(&ci, &key, &val)) {
2085                 if (key == (CSR_OFFSET | CSR_DEPENDENT_INFO)) {
2086                         peer->mgmt_addr = CSR_REGISTER_BASE + 4 * val;
2087                         break;
2088                 }
2089         }
2090         if (peer->mgmt_addr == 0ULL) {
2091                 /*
2092                  * No mgmt address effectively disables VIRT_CABLE_PLUG -
2093                  * this peer will not be able to attach to a remote
2094                  */
2095                 peer_set_state(peer, FWPS_NO_MGMT_ADDR);
2096         }
2097 
2098         spin_lock_init(&peer->lock);
2099         peer->port = NULL;
2100 
2101         init_timer(&peer->timer);
2102         INIT_WORK(&peer->work, fwserial_peer_workfn);
2103         INIT_DELAYED_WORK(&peer->connect, fwserial_auto_connect);
2104 
2105         /* associate peer with specific fw_card */
2106         peer->serial = serial;
2107         list_add_rcu(&peer->list, &serial->peer_list);
2108 
2109         fwtty_info(&peer->unit, "peer added (guid:%016llx)\n",
2110                    (unsigned long long)peer->guid);
2111 
2112         /* identify the local unit & virt cable to loopback port */
2113         if (parent->is_local) {
2114                 serial->self = peer;
2115                 if (create_loop_dev) {
2116                         struct fwtty_port *port;
2117 
2118                         port = fwserial_claim_port(peer, num_ttys);
2119                         if (!IS_ERR(port)) {
2120                                 struct virt_plug_params params;
2121 
2122                                 spin_lock_bh(&peer->lock);
2123                                 peer->port = port;
2124                                 fill_plug_params(&params, port);
2125                                 fwserial_virt_plug_complete(peer, &params);
2126                                 spin_unlock_bh(&peer->lock);
2127 
2128                                 fwtty_write_port_status(port);
2129                         }
2130                 }
2131 
2132         } else if (auto_connect) {
2133                 /* auto-attach to remote units only (if policy allows) */
2134                 schedule_delayed_work(&peer->connect, 1);
2135         }
2136 
2137         return 0;
2138 }
2139 
2140 /**
2141  * fwserial_remove_peer - remove a 'serial' unit device as a 'peer'
2142  *
2143  * Remove a 'peer' from its list of peers. This function is only
2144  * called by fwserial_remove() on bus removal of the unit device.
2145  *
2146  * Note: this function is serialized with fwserial_add_peer() by the
2147  * fwserial_list_mutex held in fwserial_remove().
2148  */
2149 static void fwserial_remove_peer(struct fwtty_peer *peer)
2150 {
2151         struct fwtty_port *port;
2152 
2153         spin_lock_bh(&peer->lock);
2154         peer_set_state(peer, FWPS_GONE);
2155         spin_unlock_bh(&peer->lock);
2156 
2157         cancel_delayed_work_sync(&peer->connect);
2158         cancel_work_sync(&peer->work);
2159 
2160         spin_lock_bh(&peer->lock);
2161         /* if this unit is the local unit, clear link */
2162         if (peer == peer->serial->self)
2163                 peer->serial->self = NULL;
2164 
2165         /* cancel the request timeout timer (if running) */
2166         del_timer(&peer->timer);
2167 
2168         port = peer->port;
2169         peer->port = NULL;
2170 
2171         list_del_rcu(&peer->list);
2172 
2173         fwtty_info(&peer->unit, "peer removed (guid:%016llx)\n",
2174                    (unsigned long long)peer->guid);
2175 
2176         spin_unlock_bh(&peer->lock);
2177 
2178         if (port)
2179                 fwserial_release_port(port, true);
2180 
2181         synchronize_rcu();
2182         kfree(peer);
2183 }
2184 
2185 /**
2186  * fwserial_create - init everything to create TTYs for a specific fw_card
2187  * @unit: fw_unit for first 'serial' unit device probed for this fw_card
2188  *
2189  * This function inits the aggregate structure (an fw_serial instance)
2190  * used to manage the TTY ports registered by a specific fw_card. Also, the
2191  * unit device is added as the first 'peer'.
2192  *
2193  * This unit device may represent a local unit device (as specified by the
2194  * config ROM unit directory) or it may represent a remote unit device
2195  * (as specified by the reading of the remote node's config ROM).
2196  *
2197  * Returns 0 to indicate "ownership" of the unit device, or a negative errno
2198  * value to indicate which error.
2199  */
2200 static int fwserial_create(struct fw_unit *unit)
2201 {
2202         struct fw_device *parent = fw_parent_device(unit);
2203         struct fw_card *card = parent->card;
2204         struct fw_serial *serial;
2205         struct fwtty_port *port;
2206         struct device *tty_dev;
2207         int i, j;
2208         int err;
2209 
2210         serial = kzalloc(sizeof(*serial), GFP_KERNEL);
2211         if (!serial)
2212                 return -ENOMEM;
2213 
2214         kref_init(&serial->kref);
2215         serial->card = card;
2216         INIT_LIST_HEAD(&serial->peer_list);
2217 
2218         for (i = 0; i < num_ports; ++i) {
2219                 port = kzalloc(sizeof(*port), GFP_KERNEL);
2220                 if (!port) {
2221                         err = -ENOMEM;
2222                         goto free_ports;
2223                 }
2224                 tty_port_init(&port->port);
2225                 port->index = FWTTY_INVALID_INDEX;
2226                 port->port.ops = &fwtty_port_ops;
2227                 port->serial = serial;
2228                 tty_buffer_set_limit(&port->port, 128 * 1024);
2229 
2230                 spin_lock_init(&port->lock);
2231                 INIT_DELAYED_WORK(&port->drain, fwtty_drain_tx);
2232                 INIT_DELAYED_WORK(&port->emit_breaks, fwtty_emit_breaks);
2233                 INIT_WORK(&port->hangup, fwtty_do_hangup);
2234                 init_waitqueue_head(&port->wait_tx);
2235                 port->max_payload = link_speed_to_max_payload(SCODE_100);
2236                 dma_fifo_init(&port->tx_fifo);
2237 
2238                 RCU_INIT_POINTER(port->peer, NULL);
2239                 serial->ports[i] = port;
2240 
2241                 /* get unique bus addr region for port's status & recv fifo */
2242                 port->rx_handler.length = FWTTY_PORT_RXFIFO_LEN + 4;
2243                 port->rx_handler.address_callback = fwtty_port_handler;
2244                 port->rx_handler.callback_data = port;
2245                 /*
2246                  * XXX: use custom memory region above cpu physical memory addrs
2247                  * this will ease porting to 64-bit firewire adapters
2248                  */
2249                 err = fw_core_add_address_handler(&port->rx_handler,
2250                                                   &fw_high_memory_region);
2251                 if (err) {
2252                         kfree(port);
2253                         goto free_ports;
2254                 }
2255         }
2256         /* preserve i for error cleanup */
2257 
2258         err = fwtty_ports_add(serial);
2259         if (err) {
2260                 fwtty_err(&unit, "no space in port table\n");
2261                 goto free_ports;
2262         }
2263 
2264         for (j = 0; j < num_ttys; ++j) {
2265                 tty_dev = tty_port_register_device(&serial->ports[j]->port,
2266                                                    fwtty_driver,
2267                                                    serial->ports[j]->index,
2268                                                    card->device);
2269                 if (IS_ERR(tty_dev)) {
2270                         err = PTR_ERR(tty_dev);
2271                         fwtty_err(&unit, "register tty device error (%d)\n",
2272                                   err);
2273                         goto unregister_ttys;
2274                 }
2275 
2276                 serial->ports[j]->device = tty_dev;
2277         }
2278         /* preserve j for error cleanup */
2279 
2280         if (create_loop_dev) {
2281                 struct device *loop_dev;
2282 
2283                 loop_dev = tty_port_register_device(&serial->ports[j]->port,
2284                                                     fwloop_driver,
2285                                                     loop_idx(serial->ports[j]),
2286                                                     card->device);
2287                 if (IS_ERR(loop_dev)) {
2288                         err = PTR_ERR(loop_dev);
2289                         fwtty_err(&unit, "create loop device failed (%d)\n",
2290                                   err);
2291                         goto unregister_ttys;
2292                 }
2293                 serial->ports[j]->device = loop_dev;
2294                 serial->ports[j]->loopback = true;
2295         }
2296 
2297         if (!IS_ERR_OR_NULL(fwserial_debugfs)) {
2298                 serial->debugfs = debugfs_create_dir(dev_name(&unit->device),
2299                                                      fwserial_debugfs);
2300                 if (!IS_ERR_OR_NULL(serial->debugfs)) {
2301                         debugfs_create_file("peers", 0444, serial->debugfs,
2302                                             serial, &fwtty_peers_fops);
2303                         debugfs_create_file("stats", 0444, serial->debugfs,
2304                                             serial, &fwtty_stats_fops);
2305                 }
2306         }
2307 
2308         list_add_rcu(&serial->list, &fwserial_list);
2309 
2310         fwtty_notice(&unit, "TTY over FireWire on device %s (guid %016llx)\n",
2311                      dev_name(card->device), (unsigned long long)card->guid);
2312 
2313         err = fwserial_add_peer(serial, unit);
2314         if (!err)
2315                 return 0;
2316 
2317         fwtty_err(&unit, "unable to add peer unit device (%d)\n", err);
2318 
2319         /* fall-through to error processing */
2320         debugfs_remove_recursive(serial->debugfs);
2321 
2322         list_del_rcu(&serial->list);
2323         if (create_loop_dev)
2324                 tty_unregister_device(fwloop_driver,
2325                                       loop_idx(serial->ports[j]));
2326 unregister_ttys:
2327         for (--j; j >= 0; --j)
2328                 tty_unregister_device(fwtty_driver, serial->ports[j]->index);
2329         kref_put(&serial->kref, fwserial_destroy);
2330         return err;
2331 
2332 free_ports:
2333         for (--i; i >= 0; --i) {
2334                 tty_port_destroy(&serial->ports[i]->port);
2335                 kfree(serial->ports[i]);
2336         }
2337         kfree(serial);
2338         return err;
2339 }
2340 
2341 /**
2342  * fwserial_probe: bus probe function for firewire 'serial' unit devices
2343  *
2344  * A 'serial' unit device is created and probed as a result of:
2345  * - declaring a ieee1394 bus id table for 'devices' matching a fabricated
2346  *   'serial' unit specifier id
2347  * - adding a unit directory to the config ROM(s) for a 'serial' unit
2348  *
2349  * The firewire core registers unit devices by enumerating unit directories
2350  * of a node's config ROM after reading the config ROM when a new node is
2351  * added to the bus topology after a bus reset.
2352  *
2353  * The practical implications of this are:
2354  * - this probe is called for both local and remote nodes that have a 'serial'
2355  *   unit directory in their config ROM (that matches the specifiers in
2356  *   fwserial_id_table).
2357  * - no specific order is enforced for local vs. remote unit devices
2358  *
2359  * This unit driver copes with the lack of specific order in the same way the
2360  * firewire net driver does -- each probe, for either a local or remote unit
2361  * device, is treated as a 'peer' (has a struct fwtty_peer instance) and the
2362  * first peer created for a given fw_card (tracked by the global fwserial_list)
2363  * creates the underlying TTYs (aggregated in a fw_serial instance).
2364  *
2365  * NB: an early attempt to differentiate local & remote unit devices by creating
2366  *     peers only for remote units and fw_serial instances (with their
2367  *     associated TTY devices) only for local units was discarded. Managing
2368  *     the peer lifetimes on device removal proved too complicated.
2369  *
2370  * fwserial_probe/fwserial_remove are effectively serialized by the
2371  * fwserial_list_mutex. This is necessary because the addition of the first peer
2372  * for a given fw_card will trigger the creation of the fw_serial for that
2373  * fw_card, which must not simultaneously contend with the removal of the
2374  * last peer for a given fw_card triggering the destruction of the same
2375  * fw_serial for the same fw_card.
2376  */
2377 static int fwserial_probe(struct fw_unit *unit,
2378                           const struct ieee1394_device_id *id)
2379 {
2380         struct fw_serial *serial;
2381         int err;
2382 
2383         mutex_lock(&fwserial_list_mutex);
2384         serial = fwserial_lookup(fw_parent_device(unit)->card);
2385         if (!serial)
2386                 err = fwserial_create(unit);
2387         else
2388                 err = fwserial_add_peer(serial, unit);
2389         mutex_unlock(&fwserial_list_mutex);
2390         return err;
2391 }
2392 
2393 /**
2394  * fwserial_remove: bus removal function for firewire 'serial' unit devices
2395  *
2396  * The corresponding 'peer' for this unit device is removed from the list of
2397  * peers for the associated fw_serial (which has a 1:1 correspondence with a
2398  * specific fw_card). If this is the last peer being removed, then trigger
2399  * the destruction of the underlying TTYs.
2400  */
2401 static void fwserial_remove(struct fw_unit *unit)
2402 {
2403         struct fwtty_peer *peer = dev_get_drvdata(&unit->device);
2404         struct fw_serial *serial = peer->serial;
2405         int i;
2406 
2407         mutex_lock(&fwserial_list_mutex);
2408         fwserial_remove_peer(peer);
2409 
2410         if (list_empty(&serial->peer_list)) {
2411                 /* unlink from the fwserial_list here */
2412                 list_del_rcu(&serial->list);
2413 
2414                 debugfs_remove_recursive(serial->debugfs);
2415 
2416                 for (i = 0; i < num_ttys; ++i)
2417                         fwserial_close_port(fwtty_driver, serial->ports[i]);
2418                 if (create_loop_dev)
2419                         fwserial_close_port(fwloop_driver, serial->ports[i]);
2420                 kref_put(&serial->kref, fwserial_destroy);
2421         }
2422         mutex_unlock(&fwserial_list_mutex);
2423 }
2424 
2425 /**
2426  * fwserial_update: bus update function for 'firewire' serial unit devices
2427  *
2428  * Updates the new node_id and bus generation for this peer. Note that locking
2429  * is unnecessary; but careful memory barrier usage is important to enforce the
2430  * load and store order of generation & node_id.
2431  *
2432  * The fw-core orders the write of node_id before generation in the parent
2433  * fw_device to ensure that a stale node_id cannot be used with a current
2434  * bus generation. So the generation value must be read before the node_id.
2435  *
2436  * In turn, this orders the write of node_id before generation in the peer to
2437  * also ensure a stale node_id cannot be used with a current bus generation.
2438  */
2439 static void fwserial_update(struct fw_unit *unit)
2440 {
2441         struct fw_device *parent = fw_parent_device(unit);
2442         struct fwtty_peer *peer = dev_get_drvdata(&unit->device);
2443         int generation;
2444 
2445         generation = parent->generation;
2446         smp_rmb();
2447         peer->node_id = parent->node_id;
2448         smp_wmb();
2449         peer->generation = generation;
2450 }
2451 
2452 static const struct ieee1394_device_id fwserial_id_table[] = {
2453         {
2454                 .match_flags  = IEEE1394_MATCH_SPECIFIER_ID |
2455                                 IEEE1394_MATCH_VERSION,
2456                 .specifier_id = LINUX_VENDOR_ID,
2457                 .version      = FWSERIAL_VERSION,
2458         },
2459         { }
2460 };
2461 
2462 static struct fw_driver fwserial_driver = {
2463         .driver = {
2464                 .owner  = THIS_MODULE,
2465                 .name   = KBUILD_MODNAME,
2466                 .bus    = &fw_bus_type,
2467         },
2468         .probe    = fwserial_probe,
2469         .update   = fwserial_update,
2470         .remove   = fwserial_remove,
2471         .id_table = fwserial_id_table,
2472 };
2473 
2474 #define FW_UNIT_SPECIFIER(id)   ((CSR_SPECIFIER_ID << 24) | (id))
2475 #define FW_UNIT_VERSION(ver)    ((CSR_VERSION << 24) | (ver))
2476 #define FW_UNIT_ADDRESS(ofs)    (((CSR_OFFSET | CSR_DEPENDENT_INFO) << 24)  \
2477                                  | (((ofs) - CSR_REGISTER_BASE) >> 2))
2478 /* XXX: config ROM definitons could be improved with semi-automated offset
2479  * and length calculation
2480  */
2481 #define FW_ROM_LEN(quads)       ((quads) << 16)
2482 #define FW_ROM_DESCRIPTOR(ofs)  (((CSR_LEAF | CSR_DESCRIPTOR) << 24) | (ofs))
2483 
2484 struct fwserial_unit_directory_data {
2485         u32     len_crc;
2486         u32     unit_specifier;
2487         u32     unit_sw_version;
2488         u32     unit_addr_offset;
2489         u32     desc1_ofs;
2490         u32     desc1_len_crc;
2491         u32     desc1_data[5];
2492 } __packed;
2493 
2494 static struct fwserial_unit_directory_data fwserial_unit_directory_data = {
2495         .len_crc = FW_ROM_LEN(4),
2496         .unit_specifier = FW_UNIT_SPECIFIER(LINUX_VENDOR_ID),
2497         .unit_sw_version = FW_UNIT_VERSION(FWSERIAL_VERSION),
2498         .desc1_ofs = FW_ROM_DESCRIPTOR(1),
2499         .desc1_len_crc = FW_ROM_LEN(5),
2500         .desc1_data = {
2501                 0x00000000,                     /*   type = text            */
2502                 0x00000000,                     /*   enc = ASCII, lang EN   */
2503                 0x4c696e75,                     /* 'Linux TTY'              */
2504                 0x78205454,
2505                 0x59000000,
2506         },
2507 };
2508 
2509 static struct fw_descriptor fwserial_unit_directory = {
2510         .length = sizeof(fwserial_unit_directory_data) / sizeof(u32),
2511         .key    = (CSR_DIRECTORY | CSR_UNIT) << 24,
2512         .data   = (u32 *)&fwserial_unit_directory_data,
2513 };
2514 
2515 /*
2516  * The management address is in the unit space region but above other known
2517  * address users (to keep wild writes from causing havoc)
2518  */
2519 static const struct fw_address_region fwserial_mgmt_addr_region = {
2520         .start = CSR_REGISTER_BASE + 0x1e0000ULL,
2521         .end = 0x1000000000000ULL,
2522 };
2523 
2524 static struct fw_address_handler fwserial_mgmt_addr_handler;
2525 
2526 /**
2527  * fwserial_handle_plug_req - handle VIRT_CABLE_PLUG request work
2528  * @work: ptr to peer->work
2529  *
2530  * Attempts to complete the VIRT_CABLE_PLUG handshake sequence for this peer.
2531  *
2532  * This checks for a collided request-- ie, that a VIRT_CABLE_PLUG request was
2533  * already sent to this peer. If so, the collision is resolved by comparing
2534  * guid values; the loser sends the plug response.
2535  *
2536  * Note: if an error prevents a response, don't do anything -- the
2537  * remote will timeout its request.
2538  */
2539 static void fwserial_handle_plug_req(struct work_struct *work)
2540 {
2541         struct fwtty_peer *peer = to_peer(work, work);
2542         struct virt_plug_params *plug_req = &peer->work_params.plug_req;
2543         struct fwtty_port *port;
2544         struct fwserial_mgmt_pkt *pkt;
2545         int rcode;
2546 
2547         pkt = kmalloc(sizeof(*pkt), GFP_KERNEL);
2548         if (!pkt)
2549                 return;
2550 
2551         port = fwserial_find_port(peer);
2552 
2553         spin_lock_bh(&peer->lock);
2554 
2555         switch (peer->state) {
2556         case FWPS_NOT_ATTACHED:
2557                 if (!port) {
2558                         fwtty_err(&peer->unit, "no more ports avail\n");
2559                         fill_plug_rsp_nack(pkt);
2560                 } else {
2561                         peer->port = port;
2562                         fill_plug_rsp_ok(pkt, peer->port);
2563                         peer_set_state(peer, FWPS_PLUG_RESPONDING);
2564                         /* don't release claimed port */
2565                         port = NULL;
2566                 }
2567                 break;
2568 
2569         case FWPS_PLUG_PENDING:
2570                 if (peer->serial->card->guid > peer->guid)
2571                         goto cleanup;
2572 
2573                 /* We lost - hijack the already-claimed port and send ok */
2574                 del_timer(&peer->timer);
2575                 fill_plug_rsp_ok(pkt, peer->port);
2576                 peer_set_state(peer, FWPS_PLUG_RESPONDING);
2577                 break;
2578 
2579         default:
2580                 fill_plug_rsp_nack(pkt);
2581         }
2582 
2583         spin_unlock_bh(&peer->lock);
2584         if (port)
2585                 fwserial_release_port(port, false);
2586 
2587         rcode = fwserial_send_mgmt_sync(peer, pkt);
2588 
2589         spin_lock_bh(&peer->lock);
2590         if (peer->state == FWPS_PLUG_RESPONDING) {
2591                 if (rcode == RCODE_COMPLETE) {
2592                         struct fwtty_port *tmp = peer->port;
2593 
2594                         fwserial_virt_plug_complete(peer, plug_req);
2595                         spin_unlock_bh(&peer->lock);
2596 
2597                         fwtty_write_port_status(tmp);
2598                         spin_lock_bh(&peer->lock);
2599                 } else {
2600                         fwtty_err(&peer->unit, "PLUG_RSP error (%d)\n", rcode);
2601                         port = peer_revert_state(peer);
2602                 }
2603         }
2604 cleanup:
2605         spin_unlock_bh(&peer->lock);
2606         if (port)
2607                 fwserial_release_port(port, false);
2608         kfree(pkt);
2609 }
2610 
2611 static void fwserial_handle_unplug_req(struct work_struct *work)
2612 {
2613         struct fwtty_peer *peer = to_peer(work, work);
2614         struct fwtty_port *port = NULL;
2615         struct fwserial_mgmt_pkt *pkt;
2616         int rcode;
2617 
2618         pkt = kmalloc(sizeof(*pkt), GFP_KERNEL);
2619         if (!pkt)
2620                 return;
2621 
2622         spin_lock_bh(&peer->lock);
2623 
2624         switch (peer->state) {
2625         case FWPS_ATTACHED:
2626                 fill_unplug_rsp_ok(pkt);
2627                 peer_set_state(peer, FWPS_UNPLUG_RESPONDING);
2628                 break;
2629 
2630         case FWPS_UNPLUG_PENDING:
2631                 if (peer->serial->card->guid > peer->guid)
2632                         goto cleanup;
2633 
2634                 /* We lost - send unplug rsp */
2635                 del_timer(&peer->timer);
2636                 fill_unplug_rsp_ok(pkt);
2637                 peer_set_state(peer, FWPS_UNPLUG_RESPONDING);
2638                 break;
2639 
2640         default:
2641                 fill_unplug_rsp_nack(pkt);
2642         }
2643 
2644         spin_unlock_bh(&peer->lock);
2645 
2646         rcode = fwserial_send_mgmt_sync(peer, pkt);
2647 
2648         spin_lock_bh(&peer->lock);
2649         if (peer->state == FWPS_UNPLUG_RESPONDING) {
2650                 if (rcode != RCODE_COMPLETE)
2651                         fwtty_err(&peer->unit, "UNPLUG_RSP error (%d)\n",
2652                                   rcode);
2653                 port = peer_revert_state(peer);
2654         }
2655 cleanup:
2656         spin_unlock_bh(&peer->lock);
2657         if (port)
2658                 fwserial_release_port(port, true);
2659         kfree(pkt);
2660 }
2661 
2662 static int fwserial_parse_mgmt_write(struct fwtty_peer *peer,
2663                                      struct fwserial_mgmt_pkt *pkt,
2664                                      unsigned long long addr,
2665                                      size_t len)
2666 {
2667         struct fwtty_port *port = NULL;
2668         bool reset = false;
2669         int rcode;
2670 
2671         if (addr != fwserial_mgmt_addr_handler.offset || len < sizeof(pkt->hdr))
2672                 return RCODE_ADDRESS_ERROR;
2673 
2674         if (len != be16_to_cpu(pkt->hdr.len) ||
2675             len != mgmt_pkt_expected_len(pkt->hdr.code))
2676                 return RCODE_DATA_ERROR;
2677 
2678         spin_lock_bh(&peer->lock);
2679         if (peer->state == FWPS_GONE) {
2680                 /*
2681                  * This should never happen - it would mean that the
2682                  * remote unit that just wrote this transaction was
2683                  * already removed from the bus -- and the removal was
2684                  * processed before we rec'd this transaction
2685                  */
2686                 fwtty_err(&peer->unit, "peer already removed\n");
2687                 spin_unlock_bh(&peer->lock);
2688                 return RCODE_ADDRESS_ERROR;
2689         }
2690 
2691         rcode = RCODE_COMPLETE;
2692 
2693         fwtty_dbg(&peer->unit, "mgmt: hdr.code: %04hx\n", pkt->hdr.code);
2694 
2695         switch (be16_to_cpu(pkt->hdr.code) & FWSC_CODE_MASK) {
2696         case FWSC_VIRT_CABLE_PLUG:
2697                 if (work_pending(&peer->work)) {
2698                         fwtty_err(&peer->unit, "plug req: busy\n");
2699                         rcode = RCODE_CONFLICT_ERROR;
2700 
2701                 } else {
2702                         peer->work_params.plug_req = pkt->plug_req;
2703                         peer->workfn = fwserial_handle_plug_req;
2704                         queue_work(system_unbound_wq, &peer->work);
2705                 }
2706                 break;
2707 
2708         case FWSC_VIRT_CABLE_PLUG_RSP:
2709                 if (peer->state != FWPS_PLUG_PENDING) {
2710                         rcode = RCODE_CONFLICT_ERROR;
2711 
2712                 } else if (be16_to_cpu(pkt->hdr.code) & FWSC_RSP_NACK) {
2713                         fwtty_notice(&peer->unit, "NACK plug rsp\n");
2714                         port = peer_revert_state(peer);
2715 
2716                 } else {
2717                         struct fwtty_port *tmp = peer->port;
2718 
2719                         fwserial_virt_plug_complete(peer, &pkt->plug_rsp);
2720                         spin_unlock_bh(&peer->lock);
2721 
2722                         fwtty_write_port_status(tmp);
2723                         spin_lock_bh(&peer->lock);
2724                 }
2725                 break;
2726 
2727         case FWSC_VIRT_CABLE_UNPLUG:
2728                 if (work_pending(&peer->work)) {
2729                         fwtty_err(&peer->unit, "unplug req: busy\n");
2730                         rcode = RCODE_CONFLICT_ERROR;
2731                 } else {
2732                         peer->workfn = fwserial_handle_unplug_req;
2733                         queue_work(system_unbound_wq, &peer->work);
2734                 }
2735                 break;
2736 
2737         case FWSC_VIRT_CABLE_UNPLUG_RSP:
2738                 if (peer->state != FWPS_UNPLUG_PENDING) {
2739                         rcode = RCODE_CONFLICT_ERROR;
2740                 } else {
2741                         if (be16_to_cpu(pkt->hdr.code) & FWSC_RSP_NACK)
2742                                 fwtty_notice(&peer->unit, "NACK unplug?\n");
2743                         port = peer_revert_state(peer);
2744                         reset = true;
2745                 }
2746                 break;
2747 
2748         default:
2749                 fwtty_err(&peer->unit, "unknown mgmt code %d\n",
2750                           be16_to_cpu(pkt->hdr.code));
2751                 rcode = RCODE_DATA_ERROR;
2752         }
2753         spin_unlock_bh(&peer->lock);
2754 
2755         if (port)
2756                 fwserial_release_port(port, reset);
2757 
2758         return rcode;
2759 }
2760 
2761 /**
2762  * fwserial_mgmt_handler: bus address handler for mgmt requests
2763  * @parameters: fw_address_callback_t as specified by firewire core interface
2764  *
2765  * This handler is responsible for handling virtual cable requests from remotes
2766  * for all cards.
2767  */
2768 static void fwserial_mgmt_handler(struct fw_card *card,
2769                                   struct fw_request *request,
2770                                   int tcode, int destination, int source,
2771                                   int generation,
2772                                   unsigned long long addr,
2773                                   void *data, size_t len,
2774                                   void *callback_data)
2775 {
2776         struct fwserial_mgmt_pkt *pkt = data;
2777         struct fwtty_peer *peer;
2778         int rcode;
2779 
2780         rcu_read_lock();
2781         peer = __fwserial_peer_by_node_id(card, generation, source);
2782         if (!peer) {
2783                 fwtty_dbg(card, "peer(%d:%x) not found\n", generation, source);
2784                 __dump_peer_list(card);
2785                 rcode = RCODE_CONFLICT_ERROR;
2786 
2787         } else {
2788                 switch (tcode) {
2789                 case TCODE_WRITE_BLOCK_REQUEST:
2790                         rcode = fwserial_parse_mgmt_write(peer, pkt, addr, len);
2791                         break;
2792 
2793                 default:
2794                         rcode = RCODE_TYPE_ERROR;
2795                 }
2796         }
2797 
2798         rcu_read_unlock();
2799         fw_send_response(card, request, rcode);
2800 }
2801 
2802 static int __init fwserial_init(void)
2803 {
2804         int err, num_loops = !!(create_loop_dev);
2805 
2806         /* XXX: placeholder for a "firewire" debugfs node */
2807         fwserial_debugfs = debugfs_create_dir(KBUILD_MODNAME, NULL);
2808 
2809         /* num_ttys/num_ports must not be set above the static alloc avail */
2810         if (num_ttys + num_loops > MAX_CARD_PORTS)
2811                 num_ttys = MAX_CARD_PORTS - num_loops;
2812 
2813         num_ports = num_ttys + num_loops;
2814 
2815         fwtty_driver = tty_alloc_driver(MAX_TOTAL_PORTS, TTY_DRIVER_REAL_RAW
2816                                         | TTY_DRIVER_DYNAMIC_DEV);
2817         if (IS_ERR(fwtty_driver)) {
2818                 err = PTR_ERR(fwtty_driver);
2819                 goto remove_debugfs;
2820         }
2821 
2822         fwtty_driver->driver_name       = KBUILD_MODNAME;
2823         fwtty_driver->name              = tty_dev_name;
2824         fwtty_driver->major             = 0;
2825         fwtty_driver->minor_start       = 0;
2826         fwtty_driver->type              = TTY_DRIVER_TYPE_SERIAL;
2827         fwtty_driver->subtype           = SERIAL_TYPE_NORMAL;
2828         fwtty_driver->init_termios          = tty_std_termios;
2829         fwtty_driver->init_termios.c_cflag  |= CLOCAL;
2830         tty_set_operations(fwtty_driver, &fwtty_ops);
2831 
2832         err = tty_register_driver(fwtty_driver);
2833         if (err) {
2834                 pr_err("register tty driver failed (%d)\n", err);
2835                 goto put_tty;
2836         }
2837 
2838         if (create_loop_dev) {
2839                 fwloop_driver = tty_alloc_driver(MAX_TOTAL_PORTS / num_ports,
2840                                                  TTY_DRIVER_REAL_RAW
2841                                                  | TTY_DRIVER_DYNAMIC_DEV);
2842                 if (IS_ERR(fwloop_driver)) {
2843                         err = PTR_ERR(fwloop_driver);
2844                         goto unregister_driver;
2845                 }
2846 
2847                 fwloop_driver->driver_name      = KBUILD_MODNAME "_loop";
2848                 fwloop_driver->name             = loop_dev_name;
2849                 fwloop_driver->major            = 0;
2850                 fwloop_driver->minor_start      = 0;
2851                 fwloop_driver->type             = TTY_DRIVER_TYPE_SERIAL;
2852                 fwloop_driver->subtype          = SERIAL_TYPE_NORMAL;
2853                 fwloop_driver->init_termios         = tty_std_termios;
2854                 fwloop_driver->init_termios.c_cflag  |= CLOCAL;
2855                 tty_set_operations(fwloop_driver, &fwloop_ops);
2856 
2857                 err = tty_register_driver(fwloop_driver);
2858                 if (err) {
2859                         pr_err("register loop driver failed (%d)\n", err);
2860                         goto put_loop;
2861                 }
2862         }
2863 
2864         fwtty_txn_cache = kmem_cache_create("fwtty_txn_cache",
2865                                             sizeof(struct fwtty_transaction),
2866                                             0, 0, fwtty_txn_constructor);
2867         if (!fwtty_txn_cache) {
2868                 err = -ENOMEM;
2869                 goto unregister_loop;
2870         }
2871 
2872         /*
2873          * Ideally, this address handler would be registered per local node
2874          * (rather than the same handler for all local nodes). However,
2875          * since the firewire core requires the config rom descriptor *before*
2876          * the local unit device(s) are created, a single management handler
2877          * must suffice for all local serial units.
2878          */
2879         fwserial_mgmt_addr_handler.length = sizeof(struct fwserial_mgmt_pkt);
2880         fwserial_mgmt_addr_handler.address_callback = fwserial_mgmt_handler;
2881 
2882         err = fw_core_add_address_handler(&fwserial_mgmt_addr_handler,
2883                                           &fwserial_mgmt_addr_region);
2884         if (err) {
2885                 pr_err("add management handler failed (%d)\n", err);
2886                 goto destroy_cache;
2887         }
2888 
2889         fwserial_unit_directory_data.unit_addr_offset =
2890                 FW_UNIT_ADDRESS(fwserial_mgmt_addr_handler.offset);
2891         err = fw_core_add_descriptor(&fwserial_unit_directory);
2892         if (err) {
2893                 pr_err("add unit descriptor failed (%d)\n", err);
2894                 goto remove_handler;
2895         }
2896 
2897         err = driver_register(&fwserial_driver.driver);
2898         if (err) {
2899                 pr_err("register fwserial driver failed (%d)\n", err);
2900                 goto remove_descriptor;
2901         }
2902 
2903         return 0;
2904 
2905 remove_descriptor:
2906         fw_core_remove_descriptor(&fwserial_unit_directory);
2907 remove_handler:
2908         fw_core_remove_address_handler(&fwserial_mgmt_addr_handler);
2909 destroy_cache:
2910         kmem_cache_destroy(fwtty_txn_cache);
2911 unregister_loop:
2912         if (create_loop_dev)
2913                 tty_unregister_driver(fwloop_driver);
2914 put_loop:
2915         if (create_loop_dev)
2916                 put_tty_driver(fwloop_driver);
2917 unregister_driver:
2918         tty_unregister_driver(fwtty_driver);
2919 put_tty:
2920         put_tty_driver(fwtty_driver);
2921 remove_debugfs:
2922         debugfs_remove_recursive(fwserial_debugfs);
2923 
2924         return err;
2925 }
2926 
2927 static void __exit fwserial_exit(void)
2928 {
2929         driver_unregister(&fwserial_driver.driver);
2930         fw_core_remove_descriptor(&fwserial_unit_directory);
2931         fw_core_remove_address_handler(&fwserial_mgmt_addr_handler);
2932         kmem_cache_destroy(fwtty_txn_cache);
2933         if (create_loop_dev) {
2934                 tty_unregister_driver(fwloop_driver);
2935                 put_tty_driver(fwloop_driver);
2936         }
2937         tty_unregister_driver(fwtty_driver);
2938         put_tty_driver(fwtty_driver);
2939         debugfs_remove_recursive(fwserial_debugfs);
2940 }
2941 
2942 module_init(fwserial_init);
2943 module_exit(fwserial_exit);
2944 
2945 MODULE_AUTHOR("Peter Hurley (peter@hurleysoftware.com)");
2946 MODULE_DESCRIPTION("FireWire Serial TTY Driver");
2947 MODULE_LICENSE("GPL");
2948 MODULE_DEVICE_TABLE(ieee1394, fwserial_id_table);
2949 MODULE_PARM_DESC(ttys, "Number of ttys to create for each local firewire node");
2950 MODULE_PARM_DESC(auto, "Auto-connect a tty to each firewire node discovered");
2951 MODULE_PARM_DESC(loop, "Create a loopback device, fwloop<n>, with ttys");
2952 

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