[PATCH] const struct tty_operations
[linux-3.10.git] / drivers / serial / serial_core.c
1 /*
2  *  linux/drivers/char/core.c
3  *
4  *  Driver core for serial ports
5  *
6  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
7  *
8  *  Copyright 1999 ARM Limited
9  *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
24  */
25 #include <linux/module.h>
26 #include <linux/tty.h>
27 #include <linux/slab.h>
28 #include <linux/init.h>
29 #include <linux/console.h>
30 #include <linux/serial_core.h>
31 #include <linux/smp_lock.h>
32 #include <linux/device.h>
33 #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
34 #include <linux/delay.h>
35 #include <linux/mutex.h>
36
37 #include <asm/irq.h>
38 #include <asm/uaccess.h>
39
40 #undef  DEBUG
41 #ifdef DEBUG
42 #define DPRINTK(x...)   printk(x)
43 #else
44 #define DPRINTK(x...)   do { } while (0)
45 #endif
46
47 /*
48  * This is used to lock changes in serial line configuration.
49  */
50 static DEFINE_MUTEX(port_mutex);
51
52 /*
53  * lockdep: port->lock is initialized in two places, but we
54  *          want only one lock-class:
55  */
56 static struct lock_class_key port_lock_key;
57
58 #define HIGH_BITS_OFFSET        ((sizeof(long)-sizeof(int))*8)
59
60 #define uart_users(state)       ((state)->count + ((state)->info ? (state)->info->blocked_open : 0))
61
62 #ifdef CONFIG_SERIAL_CORE_CONSOLE
63 #define uart_console(port)      ((port)->cons && (port)->cons->index == (port)->line)
64 #else
65 #define uart_console(port)      (0)
66 #endif
67
68 static void uart_change_speed(struct uart_state *state, struct termios *old_termios);
69 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
70 static void uart_change_pm(struct uart_state *state, int pm_state);
71
72 /*
73  * This routine is used by the interrupt handler to schedule processing in
74  * the software interrupt portion of the driver.
75  */
76 void uart_write_wakeup(struct uart_port *port)
77 {
78         struct uart_info *info = port->info;
79         /*
80          * This means you called this function _after_ the port was
81          * closed.  No cookie for you.
82          */
83         BUG_ON(!info);
84         tasklet_schedule(&info->tlet);
85 }
86
87 static void uart_stop(struct tty_struct *tty)
88 {
89         struct uart_state *state = tty->driver_data;
90         struct uart_port *port = state->port;
91         unsigned long flags;
92
93         spin_lock_irqsave(&port->lock, flags);
94         port->ops->stop_tx(port);
95         spin_unlock_irqrestore(&port->lock, flags);
96 }
97
98 static void __uart_start(struct tty_struct *tty)
99 {
100         struct uart_state *state = tty->driver_data;
101         struct uart_port *port = state->port;
102
103         if (!uart_circ_empty(&state->info->xmit) && state->info->xmit.buf &&
104             !tty->stopped && !tty->hw_stopped)
105                 port->ops->start_tx(port);
106 }
107
108 static void uart_start(struct tty_struct *tty)
109 {
110         struct uart_state *state = tty->driver_data;
111         struct uart_port *port = state->port;
112         unsigned long flags;
113
114         spin_lock_irqsave(&port->lock, flags);
115         __uart_start(tty);
116         spin_unlock_irqrestore(&port->lock, flags);
117 }
118
119 static void uart_tasklet_action(unsigned long data)
120 {
121         struct uart_state *state = (struct uart_state *)data;
122         tty_wakeup(state->info->tty);
123 }
124
125 static inline void
126 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
127 {
128         unsigned long flags;
129         unsigned int old;
130
131         spin_lock_irqsave(&port->lock, flags);
132         old = port->mctrl;
133         port->mctrl = (old & ~clear) | set;
134         if (old != port->mctrl)
135                 port->ops->set_mctrl(port, port->mctrl);
136         spin_unlock_irqrestore(&port->lock, flags);
137 }
138
139 #define uart_set_mctrl(port,set)        uart_update_mctrl(port,set,0)
140 #define uart_clear_mctrl(port,clear)    uart_update_mctrl(port,0,clear)
141
142 /*
143  * Startup the port.  This will be called once per open.  All calls
144  * will be serialised by the per-port semaphore.
145  */
146 static int uart_startup(struct uart_state *state, int init_hw)
147 {
148         struct uart_info *info = state->info;
149         struct uart_port *port = state->port;
150         unsigned long page;
151         int retval = 0;
152
153         if (info->flags & UIF_INITIALIZED)
154                 return 0;
155
156         /*
157          * Set the TTY IO error marker - we will only clear this
158          * once we have successfully opened the port.  Also set
159          * up the tty->alt_speed kludge
160          */
161         set_bit(TTY_IO_ERROR, &info->tty->flags);
162
163         if (port->type == PORT_UNKNOWN)
164                 return 0;
165
166         /*
167          * Initialise and allocate the transmit and temporary
168          * buffer.
169          */
170         if (!info->xmit.buf) {
171                 page = get_zeroed_page(GFP_KERNEL);
172                 if (!page)
173                         return -ENOMEM;
174
175                 info->xmit.buf = (unsigned char *) page;
176                 uart_circ_clear(&info->xmit);
177         }
178
179         retval = port->ops->startup(port);
180         if (retval == 0) {
181                 if (init_hw) {
182                         /*
183                          * Initialise the hardware port settings.
184                          */
185                         uart_change_speed(state, NULL);
186
187                         /*
188                          * Setup the RTS and DTR signals once the
189                          * port is open and ready to respond.
190                          */
191                         if (info->tty->termios->c_cflag & CBAUD)
192                                 uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR);
193                 }
194
195                 if (info->flags & UIF_CTS_FLOW) {
196                         spin_lock_irq(&port->lock);
197                         if (!(port->ops->get_mctrl(port) & TIOCM_CTS))
198                                 info->tty->hw_stopped = 1;
199                         spin_unlock_irq(&port->lock);
200                 }
201
202                 info->flags |= UIF_INITIALIZED;
203
204                 clear_bit(TTY_IO_ERROR, &info->tty->flags);
205         }
206
207         if (retval && capable(CAP_SYS_ADMIN))
208                 retval = 0;
209
210         return retval;
211 }
212
213 /*
214  * This routine will shutdown a serial port; interrupts are disabled, and
215  * DTR is dropped if the hangup on close termio flag is on.  Calls to
216  * uart_shutdown are serialised by the per-port semaphore.
217  */
218 static void uart_shutdown(struct uart_state *state)
219 {
220         struct uart_info *info = state->info;
221         struct uart_port *port = state->port;
222
223         /*
224          * Set the TTY IO error marker
225          */
226         if (info->tty)
227                 set_bit(TTY_IO_ERROR, &info->tty->flags);
228
229         if (info->flags & UIF_INITIALIZED) {
230                 info->flags &= ~UIF_INITIALIZED;
231
232                 /*
233                  * Turn off DTR and RTS early.
234                  */
235                 if (!info->tty || (info->tty->termios->c_cflag & HUPCL))
236                         uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
237
238                 /*
239                  * clear delta_msr_wait queue to avoid mem leaks: we may free
240                  * the irq here so the queue might never be woken up.  Note
241                  * that we won't end up waiting on delta_msr_wait again since
242                  * any outstanding file descriptors should be pointing at
243                  * hung_up_tty_fops now.
244                  */
245                 wake_up_interruptible(&info->delta_msr_wait);
246
247                 /*
248                  * Free the IRQ and disable the port.
249                  */
250                 port->ops->shutdown(port);
251
252                 /*
253                  * Ensure that the IRQ handler isn't running on another CPU.
254                  */
255                 synchronize_irq(port->irq);
256         }
257
258         /*
259          * kill off our tasklet
260          */
261         tasklet_kill(&info->tlet);
262
263         /*
264          * Free the transmit buffer page.
265          */
266         if (info->xmit.buf) {
267                 free_page((unsigned long)info->xmit.buf);
268                 info->xmit.buf = NULL;
269         }
270 }
271
272 /**
273  *      uart_update_timeout - update per-port FIFO timeout.
274  *      @port:  uart_port structure describing the port
275  *      @cflag: termios cflag value
276  *      @baud:  speed of the port
277  *
278  *      Set the port FIFO timeout value.  The @cflag value should
279  *      reflect the actual hardware settings.
280  */
281 void
282 uart_update_timeout(struct uart_port *port, unsigned int cflag,
283                     unsigned int baud)
284 {
285         unsigned int bits;
286
287         /* byte size and parity */
288         switch (cflag & CSIZE) {
289         case CS5:
290                 bits = 7;
291                 break;
292         case CS6:
293                 bits = 8;
294                 break;
295         case CS7:
296                 bits = 9;
297                 break;
298         default:
299                 bits = 10;
300                 break; // CS8
301         }
302
303         if (cflag & CSTOPB)
304                 bits++;
305         if (cflag & PARENB)
306                 bits++;
307
308         /*
309          * The total number of bits to be transmitted in the fifo.
310          */
311         bits = bits * port->fifosize;
312
313         /*
314          * Figure the timeout to send the above number of bits.
315          * Add .02 seconds of slop
316          */
317         port->timeout = (HZ * bits) / baud + HZ/50;
318 }
319
320 EXPORT_SYMBOL(uart_update_timeout);
321
322 /**
323  *      uart_get_baud_rate - return baud rate for a particular port
324  *      @port: uart_port structure describing the port in question.
325  *      @termios: desired termios settings.
326  *      @old: old termios (or NULL)
327  *      @min: minimum acceptable baud rate
328  *      @max: maximum acceptable baud rate
329  *
330  *      Decode the termios structure into a numeric baud rate,
331  *      taking account of the magic 38400 baud rate (with spd_*
332  *      flags), and mapping the %B0 rate to 9600 baud.
333  *
334  *      If the new baud rate is invalid, try the old termios setting.
335  *      If it's still invalid, we try 9600 baud.
336  *
337  *      Update the @termios structure to reflect the baud rate
338  *      we're actually going to be using.
339  */
340 unsigned int
341 uart_get_baud_rate(struct uart_port *port, struct termios *termios,
342                    struct termios *old, unsigned int min, unsigned int max)
343 {
344         unsigned int try, baud, altbaud = 38400;
345         upf_t flags = port->flags & UPF_SPD_MASK;
346
347         if (flags == UPF_SPD_HI)
348                 altbaud = 57600;
349         if (flags == UPF_SPD_VHI)
350                 altbaud = 115200;
351         if (flags == UPF_SPD_SHI)
352                 altbaud = 230400;
353         if (flags == UPF_SPD_WARP)
354                 altbaud = 460800;
355
356         for (try = 0; try < 2; try++) {
357                 baud = tty_termios_baud_rate(termios);
358
359                 /*
360                  * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
361                  * Die! Die! Die!
362                  */
363                 if (baud == 38400)
364                         baud = altbaud;
365
366                 /*
367                  * Special case: B0 rate.
368                  */
369                 if (baud == 0)
370                         baud = 9600;
371
372                 if (baud >= min && baud <= max)
373                         return baud;
374
375                 /*
376                  * Oops, the quotient was zero.  Try again with
377                  * the old baud rate if possible.
378                  */
379                 termios->c_cflag &= ~CBAUD;
380                 if (old) {
381                         termios->c_cflag |= old->c_cflag & CBAUD;
382                         old = NULL;
383                         continue;
384                 }
385
386                 /*
387                  * As a last resort, if the quotient is zero,
388                  * default to 9600 bps
389                  */
390                 termios->c_cflag |= B9600;
391         }
392
393         return 0;
394 }
395
396 EXPORT_SYMBOL(uart_get_baud_rate);
397
398 /**
399  *      uart_get_divisor - return uart clock divisor
400  *      @port: uart_port structure describing the port.
401  *      @baud: desired baud rate
402  *
403  *      Calculate the uart clock divisor for the port.
404  */
405 unsigned int
406 uart_get_divisor(struct uart_port *port, unsigned int baud)
407 {
408         unsigned int quot;
409
410         /*
411          * Old custom speed handling.
412          */
413         if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
414                 quot = port->custom_divisor;
415         else
416                 quot = (port->uartclk + (8 * baud)) / (16 * baud);
417
418         return quot;
419 }
420
421 EXPORT_SYMBOL(uart_get_divisor);
422
423 static void
424 uart_change_speed(struct uart_state *state, struct termios *old_termios)
425 {
426         struct tty_struct *tty = state->info->tty;
427         struct uart_port *port = state->port;
428         struct termios *termios;
429
430         /*
431          * If we have no tty, termios, or the port does not exist,
432          * then we can't set the parameters for this port.
433          */
434         if (!tty || !tty->termios || port->type == PORT_UNKNOWN)
435                 return;
436
437         termios = tty->termios;
438
439         /*
440          * Set flags based on termios cflag
441          */
442         if (termios->c_cflag & CRTSCTS)
443                 state->info->flags |= UIF_CTS_FLOW;
444         else
445                 state->info->flags &= ~UIF_CTS_FLOW;
446
447         if (termios->c_cflag & CLOCAL)
448                 state->info->flags &= ~UIF_CHECK_CD;
449         else
450                 state->info->flags |= UIF_CHECK_CD;
451
452         port->ops->set_termios(port, termios, old_termios);
453 }
454
455 static inline void
456 __uart_put_char(struct uart_port *port, struct circ_buf *circ, unsigned char c)
457 {
458         unsigned long flags;
459
460         if (!circ->buf)
461                 return;
462
463         spin_lock_irqsave(&port->lock, flags);
464         if (uart_circ_chars_free(circ) != 0) {
465                 circ->buf[circ->head] = c;
466                 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
467         }
468         spin_unlock_irqrestore(&port->lock, flags);
469 }
470
471 static void uart_put_char(struct tty_struct *tty, unsigned char ch)
472 {
473         struct uart_state *state = tty->driver_data;
474
475         __uart_put_char(state->port, &state->info->xmit, ch);
476 }
477
478 static void uart_flush_chars(struct tty_struct *tty)
479 {
480         uart_start(tty);
481 }
482
483 static int
484 uart_write(struct tty_struct *tty, const unsigned char *buf, int count)
485 {
486         struct uart_state *state = tty->driver_data;
487         struct uart_port *port;
488         struct circ_buf *circ;
489         unsigned long flags;
490         int c, ret = 0;
491
492         /*
493          * This means you called this function _after_ the port was
494          * closed.  No cookie for you.
495          */
496         if (!state || !state->info) {
497                 WARN_ON(1);
498                 return -EL3HLT;
499         }
500
501         port = state->port;
502         circ = &state->info->xmit;
503
504         if (!circ->buf)
505                 return 0;
506
507         spin_lock_irqsave(&port->lock, flags);
508         while (1) {
509                 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
510                 if (count < c)
511                         c = count;
512                 if (c <= 0)
513                         break;
514                 memcpy(circ->buf + circ->head, buf, c);
515                 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
516                 buf += c;
517                 count -= c;
518                 ret += c;
519         }
520         spin_unlock_irqrestore(&port->lock, flags);
521
522         uart_start(tty);
523         return ret;
524 }
525
526 static int uart_write_room(struct tty_struct *tty)
527 {
528         struct uart_state *state = tty->driver_data;
529
530         return uart_circ_chars_free(&state->info->xmit);
531 }
532
533 static int uart_chars_in_buffer(struct tty_struct *tty)
534 {
535         struct uart_state *state = tty->driver_data;
536
537         return uart_circ_chars_pending(&state->info->xmit);
538 }
539
540 static void uart_flush_buffer(struct tty_struct *tty)
541 {
542         struct uart_state *state = tty->driver_data;
543         struct uart_port *port = state->port;
544         unsigned long flags;
545
546         /*
547          * This means you called this function _after_ the port was
548          * closed.  No cookie for you.
549          */
550         if (!state || !state->info) {
551                 WARN_ON(1);
552                 return;
553         }
554
555         DPRINTK("uart_flush_buffer(%d) called\n", tty->index);
556
557         spin_lock_irqsave(&port->lock, flags);
558         uart_circ_clear(&state->info->xmit);
559         spin_unlock_irqrestore(&port->lock, flags);
560         tty_wakeup(tty);
561 }
562
563 /*
564  * This function is used to send a high-priority XON/XOFF character to
565  * the device
566  */
567 static void uart_send_xchar(struct tty_struct *tty, char ch)
568 {
569         struct uart_state *state = tty->driver_data;
570         struct uart_port *port = state->port;
571         unsigned long flags;
572
573         if (port->ops->send_xchar)
574                 port->ops->send_xchar(port, ch);
575         else {
576                 port->x_char = ch;
577                 if (ch) {
578                         spin_lock_irqsave(&port->lock, flags);
579                         port->ops->start_tx(port);
580                         spin_unlock_irqrestore(&port->lock, flags);
581                 }
582         }
583 }
584
585 static void uart_throttle(struct tty_struct *tty)
586 {
587         struct uart_state *state = tty->driver_data;
588
589         if (I_IXOFF(tty))
590                 uart_send_xchar(tty, STOP_CHAR(tty));
591
592         if (tty->termios->c_cflag & CRTSCTS)
593                 uart_clear_mctrl(state->port, TIOCM_RTS);
594 }
595
596 static void uart_unthrottle(struct tty_struct *tty)
597 {
598         struct uart_state *state = tty->driver_data;
599         struct uart_port *port = state->port;
600
601         if (I_IXOFF(tty)) {
602                 if (port->x_char)
603                         port->x_char = 0;
604                 else
605                         uart_send_xchar(tty, START_CHAR(tty));
606         }
607
608         if (tty->termios->c_cflag & CRTSCTS)
609                 uart_set_mctrl(port, TIOCM_RTS);
610 }
611
612 static int uart_get_info(struct uart_state *state,
613                          struct serial_struct __user *retinfo)
614 {
615         struct uart_port *port = state->port;
616         struct serial_struct tmp;
617
618         memset(&tmp, 0, sizeof(tmp));
619         tmp.type            = port->type;
620         tmp.line            = port->line;
621         tmp.port            = port->iobase;
622         if (HIGH_BITS_OFFSET)
623                 tmp.port_high = (long) port->iobase >> HIGH_BITS_OFFSET;
624         tmp.irq             = port->irq;
625         tmp.flags           = port->flags;
626         tmp.xmit_fifo_size  = port->fifosize;
627         tmp.baud_base       = port->uartclk / 16;
628         tmp.close_delay     = state->close_delay / 10;
629         tmp.closing_wait    = state->closing_wait == USF_CLOSING_WAIT_NONE ?
630                                 ASYNC_CLOSING_WAIT_NONE :
631                                 state->closing_wait / 10;
632         tmp.custom_divisor  = port->custom_divisor;
633         tmp.hub6            = port->hub6;
634         tmp.io_type         = port->iotype;
635         tmp.iomem_reg_shift = port->regshift;
636         tmp.iomem_base      = (void *)port->mapbase;
637
638         if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
639                 return -EFAULT;
640         return 0;
641 }
642
643 static int uart_set_info(struct uart_state *state,
644                          struct serial_struct __user *newinfo)
645 {
646         struct serial_struct new_serial;
647         struct uart_port *port = state->port;
648         unsigned long new_port;
649         unsigned int change_irq, change_port, closing_wait;
650         unsigned int old_custom_divisor, close_delay;
651         upf_t old_flags, new_flags;
652         int retval = 0;
653
654         if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
655                 return -EFAULT;
656
657         new_port = new_serial.port;
658         if (HIGH_BITS_OFFSET)
659                 new_port += (unsigned long) new_serial.port_high << HIGH_BITS_OFFSET;
660
661         new_serial.irq = irq_canonicalize(new_serial.irq);
662         close_delay = new_serial.close_delay * 10;
663         closing_wait = new_serial.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
664                         USF_CLOSING_WAIT_NONE : new_serial.closing_wait * 10;
665
666         /*
667          * This semaphore protects state->count.  It is also
668          * very useful to prevent opens.  Also, take the
669          * port configuration semaphore to make sure that a
670          * module insertion/removal doesn't change anything
671          * under us.
672          */
673         mutex_lock(&state->mutex);
674
675         change_irq  = new_serial.irq != port->irq;
676
677         /*
678          * Since changing the 'type' of the port changes its resource
679          * allocations, we should treat type changes the same as
680          * IO port changes.
681          */
682         change_port = new_port != port->iobase ||
683                       (unsigned long)new_serial.iomem_base != port->mapbase ||
684                       new_serial.hub6 != port->hub6 ||
685                       new_serial.io_type != port->iotype ||
686                       new_serial.iomem_reg_shift != port->regshift ||
687                       new_serial.type != port->type;
688
689         old_flags = port->flags;
690         new_flags = new_serial.flags;
691         old_custom_divisor = port->custom_divisor;
692
693         if (!capable(CAP_SYS_ADMIN)) {
694                 retval = -EPERM;
695                 if (change_irq || change_port ||
696                     (new_serial.baud_base != port->uartclk / 16) ||
697                     (close_delay != state->close_delay) ||
698                     (closing_wait != state->closing_wait) ||
699                     (new_serial.xmit_fifo_size &&
700                      new_serial.xmit_fifo_size != port->fifosize) ||
701                     (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
702                         goto exit;
703                 port->flags = ((port->flags & ~UPF_USR_MASK) |
704                                (new_flags & UPF_USR_MASK));
705                 port->custom_divisor = new_serial.custom_divisor;
706                 goto check_and_exit;
707         }
708
709         /*
710          * Ask the low level driver to verify the settings.
711          */
712         if (port->ops->verify_port)
713                 retval = port->ops->verify_port(port, &new_serial);
714
715         if ((new_serial.irq >= NR_IRQS) || (new_serial.irq < 0) ||
716             (new_serial.baud_base < 9600))
717                 retval = -EINVAL;
718
719         if (retval)
720                 goto exit;
721
722         if (change_port || change_irq) {
723                 retval = -EBUSY;
724
725                 /*
726                  * Make sure that we are the sole user of this port.
727                  */
728                 if (uart_users(state) > 1)
729                         goto exit;
730
731                 /*
732                  * We need to shutdown the serial port at the old
733                  * port/type/irq combination.
734                  */
735                 uart_shutdown(state);
736         }
737
738         if (change_port) {
739                 unsigned long old_iobase, old_mapbase;
740                 unsigned int old_type, old_iotype, old_hub6, old_shift;
741
742                 old_iobase = port->iobase;
743                 old_mapbase = port->mapbase;
744                 old_type = port->type;
745                 old_hub6 = port->hub6;
746                 old_iotype = port->iotype;
747                 old_shift = port->regshift;
748
749                 /*
750                  * Free and release old regions
751                  */
752                 if (old_type != PORT_UNKNOWN)
753                         port->ops->release_port(port);
754
755                 port->iobase = new_port;
756                 port->type = new_serial.type;
757                 port->hub6 = new_serial.hub6;
758                 port->iotype = new_serial.io_type;
759                 port->regshift = new_serial.iomem_reg_shift;
760                 port->mapbase = (unsigned long)new_serial.iomem_base;
761
762                 /*
763                  * Claim and map the new regions
764                  */
765                 if (port->type != PORT_UNKNOWN) {
766                         retval = port->ops->request_port(port);
767                 } else {
768                         /* Always success - Jean II */
769                         retval = 0;
770                 }
771
772                 /*
773                  * If we fail to request resources for the
774                  * new port, try to restore the old settings.
775                  */
776                 if (retval && old_type != PORT_UNKNOWN) {
777                         port->iobase = old_iobase;
778                         port->type = old_type;
779                         port->hub6 = old_hub6;
780                         port->iotype = old_iotype;
781                         port->regshift = old_shift;
782                         port->mapbase = old_mapbase;
783                         retval = port->ops->request_port(port);
784                         /*
785                          * If we failed to restore the old settings,
786                          * we fail like this.
787                          */
788                         if (retval)
789                                 port->type = PORT_UNKNOWN;
790
791                         /*
792                          * We failed anyway.
793                          */
794                         retval = -EBUSY;
795                 }
796         }
797
798         port->irq              = new_serial.irq;
799         port->uartclk          = new_serial.baud_base * 16;
800         port->flags            = (port->flags & ~UPF_CHANGE_MASK) |
801                                  (new_flags & UPF_CHANGE_MASK);
802         port->custom_divisor   = new_serial.custom_divisor;
803         state->close_delay     = close_delay;
804         state->closing_wait    = closing_wait;
805         if (new_serial.xmit_fifo_size)
806                 port->fifosize = new_serial.xmit_fifo_size;
807         if (state->info->tty)
808                 state->info->tty->low_latency =
809                         (port->flags & UPF_LOW_LATENCY) ? 1 : 0;
810
811  check_and_exit:
812         retval = 0;
813         if (port->type == PORT_UNKNOWN)
814                 goto exit;
815         if (state->info->flags & UIF_INITIALIZED) {
816                 if (((old_flags ^ port->flags) & UPF_SPD_MASK) ||
817                     old_custom_divisor != port->custom_divisor) {
818                         /*
819                          * If they're setting up a custom divisor or speed,
820                          * instead of clearing it, then bitch about it. No
821                          * need to rate-limit; it's CAP_SYS_ADMIN only.
822                          */
823                         if (port->flags & UPF_SPD_MASK) {
824                                 char buf[64];
825                                 printk(KERN_NOTICE
826                                        "%s sets custom speed on %s. This "
827                                        "is deprecated.\n", current->comm,
828                                        tty_name(state->info->tty, buf));
829                         }
830                         uart_change_speed(state, NULL);
831                 }
832         } else
833                 retval = uart_startup(state, 1);
834  exit:
835         mutex_unlock(&state->mutex);
836         return retval;
837 }
838
839
840 /*
841  * uart_get_lsr_info - get line status register info.
842  * Note: uart_ioctl protects us against hangups.
843  */
844 static int uart_get_lsr_info(struct uart_state *state,
845                              unsigned int __user *value)
846 {
847         struct uart_port *port = state->port;
848         unsigned int result;
849
850         result = port->ops->tx_empty(port);
851
852         /*
853          * If we're about to load something into the transmit
854          * register, we'll pretend the transmitter isn't empty to
855          * avoid a race condition (depending on when the transmit
856          * interrupt happens).
857          */
858         if (port->x_char ||
859             ((uart_circ_chars_pending(&state->info->xmit) > 0) &&
860              !state->info->tty->stopped && !state->info->tty->hw_stopped))
861                 result &= ~TIOCSER_TEMT;
862         
863         return put_user(result, value);
864 }
865
866 static int uart_tiocmget(struct tty_struct *tty, struct file *file)
867 {
868         struct uart_state *state = tty->driver_data;
869         struct uart_port *port = state->port;
870         int result = -EIO;
871
872         mutex_lock(&state->mutex);
873         if ((!file || !tty_hung_up_p(file)) &&
874             !(tty->flags & (1 << TTY_IO_ERROR))) {
875                 result = port->mctrl;
876
877                 spin_lock_irq(&port->lock);
878                 result |= port->ops->get_mctrl(port);
879                 spin_unlock_irq(&port->lock);
880         }
881         mutex_unlock(&state->mutex);
882
883         return result;
884 }
885
886 static int
887 uart_tiocmset(struct tty_struct *tty, struct file *file,
888               unsigned int set, unsigned int clear)
889 {
890         struct uart_state *state = tty->driver_data;
891         struct uart_port *port = state->port;
892         int ret = -EIO;
893
894         mutex_lock(&state->mutex);
895         if ((!file || !tty_hung_up_p(file)) &&
896             !(tty->flags & (1 << TTY_IO_ERROR))) {
897                 uart_update_mctrl(port, set, clear);
898                 ret = 0;
899         }
900         mutex_unlock(&state->mutex);
901         return ret;
902 }
903
904 static void uart_break_ctl(struct tty_struct *tty, int break_state)
905 {
906         struct uart_state *state = tty->driver_data;
907         struct uart_port *port = state->port;
908
909         BUG_ON(!kernel_locked());
910
911         mutex_lock(&state->mutex);
912
913         if (port->type != PORT_UNKNOWN)
914                 port->ops->break_ctl(port, break_state);
915
916         mutex_unlock(&state->mutex);
917 }
918
919 static int uart_do_autoconfig(struct uart_state *state)
920 {
921         struct uart_port *port = state->port;
922         int flags, ret;
923
924         if (!capable(CAP_SYS_ADMIN))
925                 return -EPERM;
926
927         /*
928          * Take the per-port semaphore.  This prevents count from
929          * changing, and hence any extra opens of the port while
930          * we're auto-configuring.
931          */
932         if (mutex_lock_interruptible(&state->mutex))
933                 return -ERESTARTSYS;
934
935         ret = -EBUSY;
936         if (uart_users(state) == 1) {
937                 uart_shutdown(state);
938
939                 /*
940                  * If we already have a port type configured,
941                  * we must release its resources.
942                  */
943                 if (port->type != PORT_UNKNOWN)
944                         port->ops->release_port(port);
945
946                 flags = UART_CONFIG_TYPE;
947                 if (port->flags & UPF_AUTO_IRQ)
948                         flags |= UART_CONFIG_IRQ;
949
950                 /*
951                  * This will claim the ports resources if
952                  * a port is found.
953                  */
954                 port->ops->config_port(port, flags);
955
956                 ret = uart_startup(state, 1);
957         }
958         mutex_unlock(&state->mutex);
959         return ret;
960 }
961
962 /*
963  * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
964  * - mask passed in arg for lines of interest
965  *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
966  * Caller should use TIOCGICOUNT to see which one it was
967  */
968 static int
969 uart_wait_modem_status(struct uart_state *state, unsigned long arg)
970 {
971         struct uart_port *port = state->port;
972         DECLARE_WAITQUEUE(wait, current);
973         struct uart_icount cprev, cnow;
974         int ret;
975
976         /*
977          * note the counters on entry
978          */
979         spin_lock_irq(&port->lock);
980         memcpy(&cprev, &port->icount, sizeof(struct uart_icount));
981
982         /*
983          * Force modem status interrupts on
984          */
985         port->ops->enable_ms(port);
986         spin_unlock_irq(&port->lock);
987
988         add_wait_queue(&state->info->delta_msr_wait, &wait);
989         for (;;) {
990                 spin_lock_irq(&port->lock);
991                 memcpy(&cnow, &port->icount, sizeof(struct uart_icount));
992                 spin_unlock_irq(&port->lock);
993
994                 set_current_state(TASK_INTERRUPTIBLE);
995
996                 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
997                     ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
998                     ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
999                     ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1000                         ret = 0;
1001                         break;
1002                 }
1003
1004                 schedule();
1005
1006                 /* see if a signal did it */
1007                 if (signal_pending(current)) {
1008                         ret = -ERESTARTSYS;
1009                         break;
1010                 }
1011
1012                 cprev = cnow;
1013         }
1014
1015         current->state = TASK_RUNNING;
1016         remove_wait_queue(&state->info->delta_msr_wait, &wait);
1017
1018         return ret;
1019 }
1020
1021 /*
1022  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1023  * Return: write counters to the user passed counter struct
1024  * NB: both 1->0 and 0->1 transitions are counted except for
1025  *     RI where only 0->1 is counted.
1026  */
1027 static int uart_get_count(struct uart_state *state,
1028                           struct serial_icounter_struct __user *icnt)
1029 {
1030         struct serial_icounter_struct icount;
1031         struct uart_icount cnow;
1032         struct uart_port *port = state->port;
1033
1034         spin_lock_irq(&port->lock);
1035         memcpy(&cnow, &port->icount, sizeof(struct uart_icount));
1036         spin_unlock_irq(&port->lock);
1037
1038         icount.cts         = cnow.cts;
1039         icount.dsr         = cnow.dsr;
1040         icount.rng         = cnow.rng;
1041         icount.dcd         = cnow.dcd;
1042         icount.rx          = cnow.rx;
1043         icount.tx          = cnow.tx;
1044         icount.frame       = cnow.frame;
1045         icount.overrun     = cnow.overrun;
1046         icount.parity      = cnow.parity;
1047         icount.brk         = cnow.brk;
1048         icount.buf_overrun = cnow.buf_overrun;
1049
1050         return copy_to_user(icnt, &icount, sizeof(icount)) ? -EFAULT : 0;
1051 }
1052
1053 /*
1054  * Called via sys_ioctl under the BKL.  We can use spin_lock_irq() here.
1055  */
1056 static int
1057 uart_ioctl(struct tty_struct *tty, struct file *filp, unsigned int cmd,
1058            unsigned long arg)
1059 {
1060         struct uart_state *state = tty->driver_data;
1061         void __user *uarg = (void __user *)arg;
1062         int ret = -ENOIOCTLCMD;
1063
1064         BUG_ON(!kernel_locked());
1065
1066         /*
1067          * These ioctls don't rely on the hardware to be present.
1068          */
1069         switch (cmd) {
1070         case TIOCGSERIAL:
1071                 ret = uart_get_info(state, uarg);
1072                 break;
1073
1074         case TIOCSSERIAL:
1075                 ret = uart_set_info(state, uarg);
1076                 break;
1077
1078         case TIOCSERCONFIG:
1079                 ret = uart_do_autoconfig(state);
1080                 break;
1081
1082         case TIOCSERGWILD: /* obsolete */
1083         case TIOCSERSWILD: /* obsolete */
1084                 ret = 0;
1085                 break;
1086         }
1087
1088         if (ret != -ENOIOCTLCMD)
1089                 goto out;
1090
1091         if (tty->flags & (1 << TTY_IO_ERROR)) {
1092                 ret = -EIO;
1093                 goto out;
1094         }
1095
1096         /*
1097          * The following should only be used when hardware is present.
1098          */
1099         switch (cmd) {
1100         case TIOCMIWAIT:
1101                 ret = uart_wait_modem_status(state, arg);
1102                 break;
1103
1104         case TIOCGICOUNT:
1105                 ret = uart_get_count(state, uarg);
1106                 break;
1107         }
1108
1109         if (ret != -ENOIOCTLCMD)
1110                 goto out;
1111
1112         mutex_lock(&state->mutex);
1113
1114         if (tty_hung_up_p(filp)) {
1115                 ret = -EIO;
1116                 goto out_up;
1117         }
1118
1119         /*
1120          * All these rely on hardware being present and need to be
1121          * protected against the tty being hung up.
1122          */
1123         switch (cmd) {
1124         case TIOCSERGETLSR: /* Get line status register */
1125                 ret = uart_get_lsr_info(state, uarg);
1126                 break;
1127
1128         default: {
1129                 struct uart_port *port = state->port;
1130                 if (port->ops->ioctl)
1131                         ret = port->ops->ioctl(port, cmd, arg);
1132                 break;
1133         }
1134         }
1135  out_up:
1136         mutex_unlock(&state->mutex);
1137  out:
1138         return ret;
1139 }
1140
1141 static void uart_set_termios(struct tty_struct *tty, struct termios *old_termios)
1142 {
1143         struct uart_state *state = tty->driver_data;
1144         unsigned long flags;
1145         unsigned int cflag = tty->termios->c_cflag;
1146
1147         BUG_ON(!kernel_locked());
1148
1149         /*
1150          * These are the bits that are used to setup various
1151          * flags in the low level driver.
1152          */
1153 #define RELEVANT_IFLAG(iflag)   ((iflag) & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))
1154
1155         if ((cflag ^ old_termios->c_cflag) == 0 &&
1156             RELEVANT_IFLAG(tty->termios->c_iflag ^ old_termios->c_iflag) == 0)
1157                 return;
1158
1159         uart_change_speed(state, old_termios);
1160
1161         /* Handle transition to B0 status */
1162         if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1163                 uart_clear_mctrl(state->port, TIOCM_RTS | TIOCM_DTR);
1164
1165         /* Handle transition away from B0 status */
1166         if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1167                 unsigned int mask = TIOCM_DTR;
1168                 if (!(cflag & CRTSCTS) ||
1169                     !test_bit(TTY_THROTTLED, &tty->flags))
1170                         mask |= TIOCM_RTS;
1171                 uart_set_mctrl(state->port, mask);
1172         }
1173
1174         /* Handle turning off CRTSCTS */
1175         if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {
1176                 spin_lock_irqsave(&state->port->lock, flags);
1177                 tty->hw_stopped = 0;
1178                 __uart_start(tty);
1179                 spin_unlock_irqrestore(&state->port->lock, flags);
1180         }
1181
1182         /* Handle turning on CRTSCTS */
1183         if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {
1184                 spin_lock_irqsave(&state->port->lock, flags);
1185                 if (!(state->port->ops->get_mctrl(state->port) & TIOCM_CTS)) {
1186                         tty->hw_stopped = 1;
1187                         state->port->ops->stop_tx(state->port);
1188                 }
1189                 spin_unlock_irqrestore(&state->port->lock, flags);
1190         }
1191
1192 #if 0
1193         /*
1194          * No need to wake up processes in open wait, since they
1195          * sample the CLOCAL flag once, and don't recheck it.
1196          * XXX  It's not clear whether the current behavior is correct
1197          * or not.  Hence, this may change.....
1198          */
1199         if (!(old_termios->c_cflag & CLOCAL) &&
1200             (tty->termios->c_cflag & CLOCAL))
1201                 wake_up_interruptible(&state->info->open_wait);
1202 #endif
1203 }
1204
1205 /*
1206  * In 2.4.5, calls to this will be serialized via the BKL in
1207  *  linux/drivers/char/tty_io.c:tty_release()
1208  *  linux/drivers/char/tty_io.c:do_tty_handup()
1209  */
1210 static void uart_close(struct tty_struct *tty, struct file *filp)
1211 {
1212         struct uart_state *state = tty->driver_data;
1213         struct uart_port *port;
1214         
1215         BUG_ON(!kernel_locked());
1216
1217         if (!state || !state->port)
1218                 return;
1219
1220         port = state->port;
1221
1222         DPRINTK("uart_close(%d) called\n", port->line);
1223
1224         mutex_lock(&state->mutex);
1225
1226         if (tty_hung_up_p(filp))
1227                 goto done;
1228
1229         if ((tty->count == 1) && (state->count != 1)) {
1230                 /*
1231                  * Uh, oh.  tty->count is 1, which means that the tty
1232                  * structure will be freed.  state->count should always
1233                  * be one in these conditions.  If it's greater than
1234                  * one, we've got real problems, since it means the
1235                  * serial port won't be shutdown.
1236                  */
1237                 printk(KERN_ERR "uart_close: bad serial port count; tty->count is 1, "
1238                        "state->count is %d\n", state->count);
1239                 state->count = 1;
1240         }
1241         if (--state->count < 0) {
1242                 printk(KERN_ERR "uart_close: bad serial port count for %s: %d\n",
1243                        tty->name, state->count);
1244                 state->count = 0;
1245         }
1246         if (state->count)
1247                 goto done;
1248
1249         /*
1250          * Now we wait for the transmit buffer to clear; and we notify
1251          * the line discipline to only process XON/XOFF characters by
1252          * setting tty->closing.
1253          */
1254         tty->closing = 1;
1255
1256         if (state->closing_wait != USF_CLOSING_WAIT_NONE)
1257                 tty_wait_until_sent(tty, msecs_to_jiffies(state->closing_wait));
1258
1259         /*
1260          * At this point, we stop accepting input.  To do this, we
1261          * disable the receive line status interrupts.
1262          */
1263         if (state->info->flags & UIF_INITIALIZED) {
1264                 unsigned long flags;
1265                 spin_lock_irqsave(&port->lock, flags);
1266                 port->ops->stop_rx(port);
1267                 spin_unlock_irqrestore(&port->lock, flags);
1268                 /*
1269                  * Before we drop DTR, make sure the UART transmitter
1270                  * has completely drained; this is especially
1271                  * important if there is a transmit FIFO!
1272                  */
1273                 uart_wait_until_sent(tty, port->timeout);
1274         }
1275
1276         uart_shutdown(state);
1277         uart_flush_buffer(tty);
1278
1279         tty_ldisc_flush(tty);   
1280         
1281         tty->closing = 0;
1282         state->info->tty = NULL;
1283
1284         if (state->info->blocked_open) {
1285                 if (state->close_delay)
1286                         msleep_interruptible(state->close_delay);
1287         } else if (!uart_console(port)) {
1288                 uart_change_pm(state, 3);
1289         }
1290
1291         /*
1292          * Wake up anyone trying to open this port.
1293          */
1294         state->info->flags &= ~UIF_NORMAL_ACTIVE;
1295         wake_up_interruptible(&state->info->open_wait);
1296
1297  done:
1298         mutex_unlock(&state->mutex);
1299 }
1300
1301 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1302 {
1303         struct uart_state *state = tty->driver_data;
1304         struct uart_port *port = state->port;
1305         unsigned long char_time, expire;
1306
1307         BUG_ON(!kernel_locked());
1308
1309         if (port->type == PORT_UNKNOWN || port->fifosize == 0)
1310                 return;
1311
1312         /*
1313          * Set the check interval to be 1/5 of the estimated time to
1314          * send a single character, and make it at least 1.  The check
1315          * interval should also be less than the timeout.
1316          *
1317          * Note: we have to use pretty tight timings here to satisfy
1318          * the NIST-PCTS.
1319          */
1320         char_time = (port->timeout - HZ/50) / port->fifosize;
1321         char_time = char_time / 5;
1322         if (char_time == 0)
1323                 char_time = 1;
1324         if (timeout && timeout < char_time)
1325                 char_time = timeout;
1326
1327         /*
1328          * If the transmitter hasn't cleared in twice the approximate
1329          * amount of time to send the entire FIFO, it probably won't
1330          * ever clear.  This assumes the UART isn't doing flow
1331          * control, which is currently the case.  Hence, if it ever
1332          * takes longer than port->timeout, this is probably due to a
1333          * UART bug of some kind.  So, we clamp the timeout parameter at
1334          * 2*port->timeout.
1335          */
1336         if (timeout == 0 || timeout > 2 * port->timeout)
1337                 timeout = 2 * port->timeout;
1338
1339         expire = jiffies + timeout;
1340
1341         DPRINTK("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1342                 port->line, jiffies, expire);
1343
1344         /*
1345          * Check whether the transmitter is empty every 'char_time'.
1346          * 'timeout' / 'expire' give us the maximum amount of time
1347          * we wait.
1348          */
1349         while (!port->ops->tx_empty(port)) {
1350                 msleep_interruptible(jiffies_to_msecs(char_time));
1351                 if (signal_pending(current))
1352                         break;
1353                 if (time_after(jiffies, expire))
1354                         break;
1355         }
1356         set_current_state(TASK_RUNNING); /* might not be needed */
1357 }
1358
1359 /*
1360  * This is called with the BKL held in
1361  *  linux/drivers/char/tty_io.c:do_tty_hangup()
1362  * We're called from the eventd thread, so we can sleep for
1363  * a _short_ time only.
1364  */
1365 static void uart_hangup(struct tty_struct *tty)
1366 {
1367         struct uart_state *state = tty->driver_data;
1368
1369         BUG_ON(!kernel_locked());
1370         DPRINTK("uart_hangup(%d)\n", state->port->line);
1371
1372         mutex_lock(&state->mutex);
1373         if (state->info && state->info->flags & UIF_NORMAL_ACTIVE) {
1374                 uart_flush_buffer(tty);
1375                 uart_shutdown(state);
1376                 state->count = 0;
1377                 state->info->flags &= ~UIF_NORMAL_ACTIVE;
1378                 state->info->tty = NULL;
1379                 wake_up_interruptible(&state->info->open_wait);
1380                 wake_up_interruptible(&state->info->delta_msr_wait);
1381         }
1382         mutex_unlock(&state->mutex);
1383 }
1384
1385 /*
1386  * Copy across the serial console cflag setting into the termios settings
1387  * for the initial open of the port.  This allows continuity between the
1388  * kernel settings, and the settings init adopts when it opens the port
1389  * for the first time.
1390  */
1391 static void uart_update_termios(struct uart_state *state)
1392 {
1393         struct tty_struct *tty = state->info->tty;
1394         struct uart_port *port = state->port;
1395
1396         if (uart_console(port) && port->cons->cflag) {
1397                 tty->termios->c_cflag = port->cons->cflag;
1398                 port->cons->cflag = 0;
1399         }
1400
1401         /*
1402          * If the device failed to grab its irq resources,
1403          * or some other error occurred, don't try to talk
1404          * to the port hardware.
1405          */
1406         if (!(tty->flags & (1 << TTY_IO_ERROR))) {
1407                 /*
1408                  * Make termios settings take effect.
1409                  */
1410                 uart_change_speed(state, NULL);
1411
1412                 /*
1413                  * And finally enable the RTS and DTR signals.
1414                  */
1415                 if (tty->termios->c_cflag & CBAUD)
1416                         uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS);
1417         }
1418 }
1419
1420 /*
1421  * Block the open until the port is ready.  We must be called with
1422  * the per-port semaphore held.
1423  */
1424 static int
1425 uart_block_til_ready(struct file *filp, struct uart_state *state)
1426 {
1427         DECLARE_WAITQUEUE(wait, current);
1428         struct uart_info *info = state->info;
1429         struct uart_port *port = state->port;
1430         unsigned int mctrl;
1431
1432         info->blocked_open++;
1433         state->count--;
1434
1435         add_wait_queue(&info->open_wait, &wait);
1436         while (1) {
1437                 set_current_state(TASK_INTERRUPTIBLE);
1438
1439                 /*
1440                  * If we have been hung up, tell userspace/restart open.
1441                  */
1442                 if (tty_hung_up_p(filp) || info->tty == NULL)
1443                         break;
1444
1445                 /*
1446                  * If the port has been closed, tell userspace/restart open.
1447                  */
1448                 if (!(info->flags & UIF_INITIALIZED))
1449                         break;
1450
1451                 /*
1452                  * If non-blocking mode is set, or CLOCAL mode is set,
1453                  * we don't want to wait for the modem status lines to
1454                  * indicate that the port is ready.
1455                  *
1456                  * Also, if the port is not enabled/configured, we want
1457                  * to allow the open to succeed here.  Note that we will
1458                  * have set TTY_IO_ERROR for a non-existant port.
1459                  */
1460                 if ((filp->f_flags & O_NONBLOCK) ||
1461                     (info->tty->termios->c_cflag & CLOCAL) ||
1462                     (info->tty->flags & (1 << TTY_IO_ERROR))) {
1463                         break;
1464                 }
1465
1466                 /*
1467                  * Set DTR to allow modem to know we're waiting.  Do
1468                  * not set RTS here - we want to make sure we catch
1469                  * the data from the modem.
1470                  */
1471                 if (info->tty->termios->c_cflag & CBAUD)
1472                         uart_set_mctrl(port, TIOCM_DTR);
1473
1474                 /*
1475                  * and wait for the carrier to indicate that the
1476                  * modem is ready for us.
1477                  */
1478                 spin_lock_irq(&port->lock);
1479                 port->ops->enable_ms(port);
1480                 mctrl = port->ops->get_mctrl(port);
1481                 spin_unlock_irq(&port->lock);
1482                 if (mctrl & TIOCM_CAR)
1483                         break;
1484
1485                 mutex_unlock(&state->mutex);
1486                 schedule();
1487                 mutex_lock(&state->mutex);
1488
1489                 if (signal_pending(current))
1490                         break;
1491         }
1492         set_current_state(TASK_RUNNING);
1493         remove_wait_queue(&info->open_wait, &wait);
1494
1495         state->count++;
1496         info->blocked_open--;
1497
1498         if (signal_pending(current))
1499                 return -ERESTARTSYS;
1500
1501         if (!info->tty || tty_hung_up_p(filp))
1502                 return -EAGAIN;
1503
1504         return 0;
1505 }
1506
1507 static struct uart_state *uart_get(struct uart_driver *drv, int line)
1508 {
1509         struct uart_state *state;
1510         int ret = 0;
1511
1512         state = drv->state + line;
1513         if (mutex_lock_interruptible(&state->mutex)) {
1514                 ret = -ERESTARTSYS;
1515                 goto err;
1516         }
1517
1518         state->count++;
1519         if (!state->port || state->port->flags & UPF_DEAD) {
1520                 ret = -ENXIO;
1521                 goto err_unlock;
1522         }
1523
1524         if (!state->info) {
1525                 state->info = kmalloc(sizeof(struct uart_info), GFP_KERNEL);
1526                 if (state->info) {
1527                         memset(state->info, 0, sizeof(struct uart_info));
1528                         init_waitqueue_head(&state->info->open_wait);
1529                         init_waitqueue_head(&state->info->delta_msr_wait);
1530
1531                         /*
1532                          * Link the info into the other structures.
1533                          */
1534                         state->port->info = state->info;
1535
1536                         tasklet_init(&state->info->tlet, uart_tasklet_action,
1537                                      (unsigned long)state);
1538                 } else {
1539                         ret = -ENOMEM;
1540                         goto err_unlock;
1541                 }
1542         }
1543         return state;
1544
1545  err_unlock:
1546         state->count--;
1547         mutex_unlock(&state->mutex);
1548  err:
1549         return ERR_PTR(ret);
1550 }
1551
1552 /*
1553  * In 2.4.5, calls to uart_open are serialised by the BKL in
1554  *   linux/fs/devices.c:chrdev_open()
1555  * Note that if this fails, then uart_close() _will_ be called.
1556  *
1557  * In time, we want to scrap the "opening nonpresent ports"
1558  * behaviour and implement an alternative way for setserial
1559  * to set base addresses/ports/types.  This will allow us to
1560  * get rid of a certain amount of extra tests.
1561  */
1562 static int uart_open(struct tty_struct *tty, struct file *filp)
1563 {
1564         struct uart_driver *drv = (struct uart_driver *)tty->driver->driver_state;
1565         struct uart_state *state;
1566         int retval, line = tty->index;
1567
1568         BUG_ON(!kernel_locked());
1569         DPRINTK("uart_open(%d) called\n", line);
1570
1571         /*
1572          * tty->driver->num won't change, so we won't fail here with
1573          * tty->driver_data set to something non-NULL (and therefore
1574          * we won't get caught by uart_close()).
1575          */
1576         retval = -ENODEV;
1577         if (line >= tty->driver->num)
1578                 goto fail;
1579
1580         /*
1581          * We take the semaphore inside uart_get to guarantee that we won't
1582          * be re-entered while allocating the info structure, or while we
1583          * request any IRQs that the driver may need.  This also has the nice
1584          * side-effect that it delays the action of uart_hangup, so we can
1585          * guarantee that info->tty will always contain something reasonable.
1586          */
1587         state = uart_get(drv, line);
1588         if (IS_ERR(state)) {
1589                 retval = PTR_ERR(state);
1590                 goto fail;
1591         }
1592
1593         /*
1594          * Once we set tty->driver_data here, we are guaranteed that
1595          * uart_close() will decrement the driver module use count.
1596          * Any failures from here onwards should not touch the count.
1597          */
1598         tty->driver_data = state;
1599         tty->low_latency = (state->port->flags & UPF_LOW_LATENCY) ? 1 : 0;
1600         tty->alt_speed = 0;
1601         state->info->tty = tty;
1602
1603         /*
1604          * If the port is in the middle of closing, bail out now.
1605          */
1606         if (tty_hung_up_p(filp)) {
1607                 retval = -EAGAIN;
1608                 state->count--;
1609                 mutex_unlock(&state->mutex);
1610                 goto fail;
1611         }
1612
1613         /*
1614          * Make sure the device is in D0 state.
1615          */
1616         if (state->count == 1)
1617                 uart_change_pm(state, 0);
1618
1619         /*
1620          * Start up the serial port.
1621          */
1622         retval = uart_startup(state, 0);
1623
1624         /*
1625          * If we succeeded, wait until the port is ready.
1626          */
1627         if (retval == 0)
1628                 retval = uart_block_til_ready(filp, state);
1629         mutex_unlock(&state->mutex);
1630
1631         /*
1632          * If this is the first open to succeed, adjust things to suit.
1633          */
1634         if (retval == 0 && !(state->info->flags & UIF_NORMAL_ACTIVE)) {
1635                 state->info->flags |= UIF_NORMAL_ACTIVE;
1636
1637                 uart_update_termios(state);
1638         }
1639
1640  fail:
1641         return retval;
1642 }
1643
1644 static const char *uart_type(struct uart_port *port)
1645 {
1646         const char *str = NULL;
1647
1648         if (port->ops->type)
1649                 str = port->ops->type(port);
1650
1651         if (!str)
1652                 str = "unknown";
1653
1654         return str;
1655 }
1656
1657 #ifdef CONFIG_PROC_FS
1658
1659 static int uart_line_info(char *buf, struct uart_driver *drv, int i)
1660 {
1661         struct uart_state *state = drv->state + i;
1662         struct uart_port *port = state->port;
1663         char stat_buf[32];
1664         unsigned int status;
1665         int ret;
1666
1667         if (!port)
1668                 return 0;
1669
1670         ret = sprintf(buf, "%d: uart:%s %s%08lX irq:%d",
1671                         port->line, uart_type(port),
1672                         port->iotype == UPIO_MEM ? "mmio:0x" : "port:",
1673                         port->iotype == UPIO_MEM ? port->mapbase :
1674                                                 (unsigned long) port->iobase,
1675                         port->irq);
1676
1677         if (port->type == PORT_UNKNOWN) {
1678                 strcat(buf, "\n");
1679                 return ret + 1;
1680         }
1681
1682         if(capable(CAP_SYS_ADMIN))
1683         {
1684                 spin_lock_irq(&port->lock);
1685                 status = port->ops->get_mctrl(port);
1686                 spin_unlock_irq(&port->lock);
1687
1688                 ret += sprintf(buf + ret, " tx:%d rx:%d",
1689                                 port->icount.tx, port->icount.rx);
1690                 if (port->icount.frame)
1691                         ret += sprintf(buf + ret, " fe:%d",
1692                                 port->icount.frame);
1693                 if (port->icount.parity)
1694                         ret += sprintf(buf + ret, " pe:%d",
1695                                 port->icount.parity);
1696                 if (port->icount.brk)
1697                         ret += sprintf(buf + ret, " brk:%d",
1698                                 port->icount.brk);
1699                 if (port->icount.overrun)
1700                         ret += sprintf(buf + ret, " oe:%d",
1701                                 port->icount.overrun);
1702         
1703 #define INFOBIT(bit,str) \
1704         if (port->mctrl & (bit)) \
1705                 strncat(stat_buf, (str), sizeof(stat_buf) - \
1706                         strlen(stat_buf) - 2)
1707 #define STATBIT(bit,str) \
1708         if (status & (bit)) \
1709                 strncat(stat_buf, (str), sizeof(stat_buf) - \
1710                        strlen(stat_buf) - 2)
1711
1712                 stat_buf[0] = '\0';
1713                 stat_buf[1] = '\0';
1714                 INFOBIT(TIOCM_RTS, "|RTS");
1715                 STATBIT(TIOCM_CTS, "|CTS");
1716                 INFOBIT(TIOCM_DTR, "|DTR");
1717                 STATBIT(TIOCM_DSR, "|DSR");
1718                 STATBIT(TIOCM_CAR, "|CD");
1719                 STATBIT(TIOCM_RNG, "|RI");
1720                 if (stat_buf[0])
1721                         stat_buf[0] = ' ';
1722                 strcat(stat_buf, "\n");
1723         
1724                 ret += sprintf(buf + ret, stat_buf);
1725         } else {
1726                 strcat(buf, "\n");
1727                 ret++;
1728         }
1729 #undef STATBIT
1730 #undef INFOBIT
1731         return ret;
1732 }
1733
1734 static int uart_read_proc(char *page, char **start, off_t off,
1735                           int count, int *eof, void *data)
1736 {
1737         struct tty_driver *ttydrv = data;
1738         struct uart_driver *drv = ttydrv->driver_state;
1739         int i, len = 0, l;
1740         off_t begin = 0;
1741
1742         len += sprintf(page, "serinfo:1.0 driver%s%s revision:%s\n",
1743                         "", "", "");
1744         for (i = 0; i < drv->nr && len < PAGE_SIZE - 96; i++) {
1745                 l = uart_line_info(page + len, drv, i);
1746                 len += l;
1747                 if (len + begin > off + count)
1748                         goto done;
1749                 if (len + begin < off) {
1750                         begin += len;
1751                         len = 0;
1752                 }
1753         }
1754         *eof = 1;
1755  done:
1756         if (off >= len + begin)
1757                 return 0;
1758         *start = page + (off - begin);
1759         return (count < begin + len - off) ? count : (begin + len - off);
1760 }
1761 #endif
1762
1763 #ifdef CONFIG_SERIAL_CORE_CONSOLE
1764 /*
1765  *      uart_console_write - write a console message to a serial port
1766  *      @port: the port to write the message
1767  *      @s: array of characters
1768  *      @count: number of characters in string to write
1769  *      @write: function to write character to port
1770  */
1771 void uart_console_write(struct uart_port *port, const char *s,
1772                         unsigned int count,
1773                         void (*putchar)(struct uart_port *, int))
1774 {
1775         unsigned int i;
1776
1777         for (i = 0; i < count; i++, s++) {
1778                 if (*s == '\n')
1779                         putchar(port, '\r');
1780                 putchar(port, *s);
1781         }
1782 }
1783 EXPORT_SYMBOL_GPL(uart_console_write);
1784
1785 /*
1786  *      Check whether an invalid uart number has been specified, and
1787  *      if so, search for the first available port that does have
1788  *      console support.
1789  */
1790 struct uart_port * __init
1791 uart_get_console(struct uart_port *ports, int nr, struct console *co)
1792 {
1793         int idx = co->index;
1794
1795         if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
1796                                      ports[idx].membase == NULL))
1797                 for (idx = 0; idx < nr; idx++)
1798                         if (ports[idx].iobase != 0 ||
1799                             ports[idx].membase != NULL)
1800                                 break;
1801
1802         co->index = idx;
1803
1804         return ports + idx;
1805 }
1806
1807 /**
1808  *      uart_parse_options - Parse serial port baud/parity/bits/flow contro.
1809  *      @options: pointer to option string
1810  *      @baud: pointer to an 'int' variable for the baud rate.
1811  *      @parity: pointer to an 'int' variable for the parity.
1812  *      @bits: pointer to an 'int' variable for the number of data bits.
1813  *      @flow: pointer to an 'int' variable for the flow control character.
1814  *
1815  *      uart_parse_options decodes a string containing the serial console
1816  *      options.  The format of the string is <baud><parity><bits><flow>,
1817  *      eg: 115200n8r
1818  */
1819 void __init
1820 uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow)
1821 {
1822         char *s = options;
1823
1824         *baud = simple_strtoul(s, NULL, 10);
1825         while (*s >= '0' && *s <= '9')
1826                 s++;
1827         if (*s)
1828                 *parity = *s++;
1829         if (*s)
1830                 *bits = *s++ - '0';
1831         if (*s)
1832                 *flow = *s;
1833 }
1834
1835 struct baud_rates {
1836         unsigned int rate;
1837         unsigned int cflag;
1838 };
1839
1840 static const struct baud_rates baud_rates[] = {
1841         { 921600, B921600 },
1842         { 460800, B460800 },
1843         { 230400, B230400 },
1844         { 115200, B115200 },
1845         {  57600, B57600  },
1846         {  38400, B38400  },
1847         {  19200, B19200  },
1848         {   9600, B9600   },
1849         {   4800, B4800   },
1850         {   2400, B2400   },
1851         {   1200, B1200   },
1852         {      0, B38400  }
1853 };
1854
1855 /**
1856  *      uart_set_options - setup the serial console parameters
1857  *      @port: pointer to the serial ports uart_port structure
1858  *      @co: console pointer
1859  *      @baud: baud rate
1860  *      @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
1861  *      @bits: number of data bits
1862  *      @flow: flow control character - 'r' (rts)
1863  */
1864 int __init
1865 uart_set_options(struct uart_port *port, struct console *co,
1866                  int baud, int parity, int bits, int flow)
1867 {
1868         struct termios termios;
1869         int i;
1870
1871         /*
1872          * Ensure that the serial console lock is initialised
1873          * early.
1874          */
1875         spin_lock_init(&port->lock);
1876         lockdep_set_class(&port->lock, &port_lock_key);
1877
1878         memset(&termios, 0, sizeof(struct termios));
1879
1880         termios.c_cflag = CREAD | HUPCL | CLOCAL;
1881
1882         /*
1883          * Construct a cflag setting.
1884          */
1885         for (i = 0; baud_rates[i].rate; i++)
1886                 if (baud_rates[i].rate <= baud)
1887                         break;
1888
1889         termios.c_cflag |= baud_rates[i].cflag;
1890
1891         if (bits == 7)
1892                 termios.c_cflag |= CS7;
1893         else
1894                 termios.c_cflag |= CS8;
1895
1896         switch (parity) {
1897         case 'o': case 'O':
1898                 termios.c_cflag |= PARODD;
1899                 /*fall through*/
1900         case 'e': case 'E':
1901                 termios.c_cflag |= PARENB;
1902                 break;
1903         }
1904
1905         if (flow == 'r')
1906                 termios.c_cflag |= CRTSCTS;
1907
1908         port->ops->set_termios(port, &termios, NULL);
1909         co->cflag = termios.c_cflag;
1910
1911         return 0;
1912 }
1913 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
1914
1915 static void uart_change_pm(struct uart_state *state, int pm_state)
1916 {
1917         struct uart_port *port = state->port;
1918
1919         if (state->pm_state != pm_state) {
1920                 if (port->ops->pm)
1921                         port->ops->pm(port, pm_state, state->pm_state);
1922                 state->pm_state = pm_state;
1923         }
1924 }
1925
1926 int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
1927 {
1928         struct uart_state *state = drv->state + port->line;
1929
1930         mutex_lock(&state->mutex);
1931
1932 #ifdef CONFIG_DISABLE_CONSOLE_SUSPEND
1933         if (uart_console(port)) {
1934                 mutex_unlock(&state->mutex);
1935                 return 0;
1936         }
1937 #endif
1938
1939         if (state->info && state->info->flags & UIF_INITIALIZED) {
1940                 const struct uart_ops *ops = port->ops;
1941
1942                 spin_lock_irq(&port->lock);
1943                 ops->stop_tx(port);
1944                 ops->set_mctrl(port, 0);
1945                 ops->stop_rx(port);
1946                 spin_unlock_irq(&port->lock);
1947
1948                 /*
1949                  * Wait for the transmitter to empty.
1950                  */
1951                 while (!ops->tx_empty(port)) {
1952                         msleep(10);
1953                 }
1954
1955                 ops->shutdown(port);
1956         }
1957
1958         /*
1959          * Disable the console device before suspending.
1960          */
1961         if (uart_console(port))
1962                 console_stop(port->cons);
1963
1964         uart_change_pm(state, 3);
1965
1966         mutex_unlock(&state->mutex);
1967
1968         return 0;
1969 }
1970
1971 int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
1972 {
1973         struct uart_state *state = drv->state + port->line;
1974
1975         mutex_lock(&state->mutex);
1976
1977 #ifdef CONFIG_DISABLE_CONSOLE_SUSPEND
1978         if (uart_console(port)) {
1979                 mutex_unlock(&state->mutex);
1980                 return 0;
1981         }
1982 #endif
1983
1984         uart_change_pm(state, 0);
1985
1986         /*
1987          * Re-enable the console device after suspending.
1988          */
1989         if (uart_console(port)) {
1990                 struct termios termios;
1991
1992                 /*
1993                  * First try to use the console cflag setting.
1994                  */
1995                 memset(&termios, 0, sizeof(struct termios));
1996                 termios.c_cflag = port->cons->cflag;
1997
1998                 /*
1999                  * If that's unset, use the tty termios setting.
2000                  */
2001                 if (state->info && state->info->tty && termios.c_cflag == 0)
2002                         termios = *state->info->tty->termios;
2003
2004                 port->ops->set_termios(port, &termios, NULL);
2005                 console_start(port->cons);
2006         }
2007
2008         if (state->info && state->info->flags & UIF_INITIALIZED) {
2009                 const struct uart_ops *ops = port->ops;
2010                 int ret;
2011
2012                 ops->set_mctrl(port, 0);
2013                 ret = ops->startup(port);
2014                 if (ret == 0) {
2015                         uart_change_speed(state, NULL);
2016                         spin_lock_irq(&port->lock);
2017                         ops->set_mctrl(port, port->mctrl);
2018                         ops->start_tx(port);
2019                         spin_unlock_irq(&port->lock);
2020                 } else {
2021                         /*
2022                          * Failed to resume - maybe hardware went away?
2023                          * Clear the "initialized" flag so we won't try
2024                          * to call the low level drivers shutdown method.
2025                          */
2026                         state->info->flags &= ~UIF_INITIALIZED;
2027                         uart_shutdown(state);
2028                 }
2029         }
2030
2031         mutex_unlock(&state->mutex);
2032
2033         return 0;
2034 }
2035
2036 static inline void
2037 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2038 {
2039         char address[64];
2040
2041         switch (port->iotype) {
2042         case UPIO_PORT:
2043                 snprintf(address, sizeof(address),
2044                          "I/O 0x%x", port->iobase);
2045                 break;
2046         case UPIO_HUB6:
2047                 snprintf(address, sizeof(address),
2048                          "I/O 0x%x offset 0x%x", port->iobase, port->hub6);
2049                 break;
2050         case UPIO_MEM:
2051         case UPIO_MEM32:
2052         case UPIO_AU:
2053         case UPIO_TSI:
2054                 snprintf(address, sizeof(address),
2055                          "MMIO 0x%lx", port->mapbase);
2056                 break;
2057         default:
2058                 strlcpy(address, "*unknown*", sizeof(address));
2059                 break;
2060         }
2061
2062         printk(KERN_INFO "%s%s%s%d at %s (irq = %d) is a %s\n",
2063                port->dev ? port->dev->bus_id : "",
2064                port->dev ? ": " : "",
2065                drv->dev_name, port->line, address, port->irq, uart_type(port));
2066 }
2067
2068 static void
2069 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2070                     struct uart_port *port)
2071 {
2072         unsigned int flags;
2073
2074         /*
2075          * If there isn't a port here, don't do anything further.
2076          */
2077         if (!port->iobase && !port->mapbase && !port->membase)
2078                 return;
2079
2080         /*
2081          * Now do the auto configuration stuff.  Note that config_port
2082          * is expected to claim the resources and map the port for us.
2083          */
2084         flags = UART_CONFIG_TYPE;
2085         if (port->flags & UPF_AUTO_IRQ)
2086                 flags |= UART_CONFIG_IRQ;
2087         if (port->flags & UPF_BOOT_AUTOCONF) {
2088                 port->type = PORT_UNKNOWN;
2089                 port->ops->config_port(port, flags);
2090         }
2091
2092         if (port->type != PORT_UNKNOWN) {
2093                 unsigned long flags;
2094
2095                 uart_report_port(drv, port);
2096
2097                 /*
2098                  * Ensure that the modem control lines are de-activated.
2099                  * We probably don't need a spinlock around this, but
2100                  */
2101                 spin_lock_irqsave(&port->lock, flags);
2102                 port->ops->set_mctrl(port, 0);
2103                 spin_unlock_irqrestore(&port->lock, flags);
2104
2105                 /*
2106                  * Power down all ports by default, except the
2107                  * console if we have one.
2108                  */
2109                 if (!uart_console(port))
2110                         uart_change_pm(state, 3);
2111         }
2112 }
2113
2114 static const struct tty_operations uart_ops = {
2115         .open           = uart_open,
2116         .close          = uart_close,
2117         .write          = uart_write,
2118         .put_char       = uart_put_char,
2119         .flush_chars    = uart_flush_chars,
2120         .write_room     = uart_write_room,
2121         .chars_in_buffer= uart_chars_in_buffer,
2122         .flush_buffer   = uart_flush_buffer,
2123         .ioctl          = uart_ioctl,
2124         .throttle       = uart_throttle,
2125         .unthrottle     = uart_unthrottle,
2126         .send_xchar     = uart_send_xchar,
2127         .set_termios    = uart_set_termios,
2128         .stop           = uart_stop,
2129         .start          = uart_start,
2130         .hangup         = uart_hangup,
2131         .break_ctl      = uart_break_ctl,
2132         .wait_until_sent= uart_wait_until_sent,
2133 #ifdef CONFIG_PROC_FS
2134         .read_proc      = uart_read_proc,
2135 #endif
2136         .tiocmget       = uart_tiocmget,
2137         .tiocmset       = uart_tiocmset,
2138 };
2139
2140 /**
2141  *      uart_register_driver - register a driver with the uart core layer
2142  *      @drv: low level driver structure
2143  *
2144  *      Register a uart driver with the core driver.  We in turn register
2145  *      with the tty layer, and initialise the core driver per-port state.
2146  *
2147  *      We have a proc file in /proc/tty/driver which is named after the
2148  *      normal driver.
2149  *
2150  *      drv->port should be NULL, and the per-port structures should be
2151  *      registered using uart_add_one_port after this call has succeeded.
2152  */
2153 int uart_register_driver(struct uart_driver *drv)
2154 {
2155         struct tty_driver *normal = NULL;
2156         int i, retval;
2157
2158         BUG_ON(drv->state);
2159
2160         /*
2161          * Maybe we should be using a slab cache for this, especially if
2162          * we have a large number of ports to handle.
2163          */
2164         drv->state = kmalloc(sizeof(struct uart_state) * drv->nr, GFP_KERNEL);
2165         retval = -ENOMEM;
2166         if (!drv->state)
2167                 goto out;
2168
2169         memset(drv->state, 0, sizeof(struct uart_state) * drv->nr);
2170
2171         normal  = alloc_tty_driver(drv->nr);
2172         if (!normal)
2173                 goto out;
2174
2175         drv->tty_driver = normal;
2176
2177         normal->owner           = drv->owner;
2178         normal->driver_name     = drv->driver_name;
2179         normal->name            = drv->dev_name;
2180         normal->major           = drv->major;
2181         normal->minor_start     = drv->minor;
2182         normal->type            = TTY_DRIVER_TYPE_SERIAL;
2183         normal->subtype         = SERIAL_TYPE_NORMAL;
2184         normal->init_termios    = tty_std_termios;
2185         normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2186         normal->flags           = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
2187         normal->driver_state    = drv;
2188         tty_set_operations(normal, &uart_ops);
2189
2190         /*
2191          * Initialise the UART state(s).
2192          */
2193         for (i = 0; i < drv->nr; i++) {
2194                 struct uart_state *state = drv->state + i;
2195
2196                 state->close_delay     = 500;   /* .5 seconds */
2197                 state->closing_wait    = 30000; /* 30 seconds */
2198
2199                 mutex_init(&state->mutex);
2200         }
2201
2202         retval = tty_register_driver(normal);
2203  out:
2204         if (retval < 0) {
2205                 put_tty_driver(normal);
2206                 kfree(drv->state);
2207         }
2208         return retval;
2209 }
2210
2211 /**
2212  *      uart_unregister_driver - remove a driver from the uart core layer
2213  *      @drv: low level driver structure
2214  *
2215  *      Remove all references to a driver from the core driver.  The low
2216  *      level driver must have removed all its ports via the
2217  *      uart_remove_one_port() if it registered them with uart_add_one_port().
2218  *      (ie, drv->port == NULL)
2219  */
2220 void uart_unregister_driver(struct uart_driver *drv)
2221 {
2222         struct tty_driver *p = drv->tty_driver;
2223         tty_unregister_driver(p);
2224         put_tty_driver(p);
2225         kfree(drv->state);
2226         drv->tty_driver = NULL;
2227 }
2228
2229 struct tty_driver *uart_console_device(struct console *co, int *index)
2230 {
2231         struct uart_driver *p = co->data;
2232         *index = co->index;
2233         return p->tty_driver;
2234 }
2235
2236 /**
2237  *      uart_add_one_port - attach a driver-defined port structure
2238  *      @drv: pointer to the uart low level driver structure for this port
2239  *      @port: uart port structure to use for this port.
2240  *
2241  *      This allows the driver to register its own uart_port structure
2242  *      with the core driver.  The main purpose is to allow the low
2243  *      level uart drivers to expand uart_port, rather than having yet
2244  *      more levels of structures.
2245  */
2246 int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
2247 {
2248         struct uart_state *state;
2249         int ret = 0;
2250
2251         BUG_ON(in_interrupt());
2252
2253         if (port->line >= drv->nr)
2254                 return -EINVAL;
2255
2256         state = drv->state + port->line;
2257
2258         mutex_lock(&port_mutex);
2259         mutex_lock(&state->mutex);
2260         if (state->port) {
2261                 ret = -EINVAL;
2262                 goto out;
2263         }
2264
2265         state->port = port;
2266
2267         port->cons = drv->cons;
2268         port->info = state->info;
2269
2270         /*
2271          * If this port is a console, then the spinlock is already
2272          * initialised.
2273          */
2274         if (!(uart_console(port) && (port->cons->flags & CON_ENABLED))) {
2275                 spin_lock_init(&port->lock);
2276                 lockdep_set_class(&port->lock, &port_lock_key);
2277         }
2278
2279         uart_configure_port(drv, state, port);
2280
2281         /*
2282          * Register the port whether it's detected or not.  This allows
2283          * setserial to be used to alter this ports parameters.
2284          */
2285         tty_register_device(drv->tty_driver, port->line, port->dev);
2286
2287         /*
2288          * If this driver supports console, and it hasn't been
2289          * successfully registered yet, try to re-register it.
2290          * It may be that the port was not available.
2291          */
2292         if (port->type != PORT_UNKNOWN &&
2293             port->cons && !(port->cons->flags & CON_ENABLED))
2294                 register_console(port->cons);
2295
2296         /*
2297          * Ensure UPF_DEAD is not set.
2298          */
2299         port->flags &= ~UPF_DEAD;
2300
2301  out:
2302         mutex_unlock(&state->mutex);
2303         mutex_unlock(&port_mutex);
2304
2305         return ret;
2306 }
2307
2308 /**
2309  *      uart_remove_one_port - detach a driver defined port structure
2310  *      @drv: pointer to the uart low level driver structure for this port
2311  *      @port: uart port structure for this port
2312  *
2313  *      This unhooks (and hangs up) the specified port structure from the
2314  *      core driver.  No further calls will be made to the low-level code
2315  *      for this port.
2316  */
2317 int uart_remove_one_port(struct uart_driver *drv, struct uart_port *port)
2318 {
2319         struct uart_state *state = drv->state + port->line;
2320         struct uart_info *info;
2321
2322         BUG_ON(in_interrupt());
2323
2324         if (state->port != port)
2325                 printk(KERN_ALERT "Removing wrong port: %p != %p\n",
2326                         state->port, port);
2327
2328         mutex_lock(&port_mutex);
2329
2330         /*
2331          * Mark the port "dead" - this prevents any opens from
2332          * succeeding while we shut down the port.
2333          */
2334         mutex_lock(&state->mutex);
2335         port->flags |= UPF_DEAD;
2336         mutex_unlock(&state->mutex);
2337
2338         /*
2339          * Remove the devices from the tty layer
2340          */
2341         tty_unregister_device(drv->tty_driver, port->line);
2342
2343         info = state->info;
2344         if (info && info->tty)
2345                 tty_vhangup(info->tty);
2346
2347         /*
2348          * All users of this port should now be disconnected from
2349          * this driver, and the port shut down.  We should be the
2350          * only thread fiddling with this port from now on.
2351          */
2352         state->info = NULL;
2353
2354         /*
2355          * Free the port IO and memory resources, if any.
2356          */
2357         if (port->type != PORT_UNKNOWN)
2358                 port->ops->release_port(port);
2359
2360         /*
2361          * Indicate that there isn't a port here anymore.
2362          */
2363         port->type = PORT_UNKNOWN;
2364
2365         /*
2366          * Kill the tasklet, and free resources.
2367          */
2368         if (info) {
2369                 tasklet_kill(&info->tlet);
2370                 kfree(info);
2371         }
2372
2373         state->port = NULL;
2374         mutex_unlock(&port_mutex);
2375
2376         return 0;
2377 }
2378
2379 /*
2380  *      Are the two ports equivalent?
2381  */
2382 int uart_match_port(struct uart_port *port1, struct uart_port *port2)
2383 {
2384         if (port1->iotype != port2->iotype)
2385                 return 0;
2386
2387         switch (port1->iotype) {
2388         case UPIO_PORT:
2389                 return (port1->iobase == port2->iobase);
2390         case UPIO_HUB6:
2391                 return (port1->iobase == port2->iobase) &&
2392                        (port1->hub6   == port2->hub6);
2393         case UPIO_MEM:
2394         case UPIO_MEM32:
2395         case UPIO_AU:
2396         case UPIO_TSI:
2397                 return (port1->mapbase == port2->mapbase);
2398         }
2399         return 0;
2400 }
2401 EXPORT_SYMBOL(uart_match_port);
2402
2403 EXPORT_SYMBOL(uart_write_wakeup);
2404 EXPORT_SYMBOL(uart_register_driver);
2405 EXPORT_SYMBOL(uart_unregister_driver);
2406 EXPORT_SYMBOL(uart_suspend_port);
2407 EXPORT_SYMBOL(uart_resume_port);
2408 EXPORT_SYMBOL(uart_add_one_port);
2409 EXPORT_SYMBOL(uart_remove_one_port);
2410
2411 MODULE_DESCRIPTION("Serial driver core");
2412 MODULE_LICENSE("GPL");