Merge ../ntfs-2.6-devel
[linux-2.6] / 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/config.h>
26 #include <linux/module.h>
27 #include <linux/tty.h>
28 #include <linux/slab.h>
29 #include <linux/init.h>
30 #include <linux/console.h>
31 #include <linux/serial_core.h>
32 #include <linux/smp_lock.h>
33 #include <linux/device.h>
34 #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
35 #include <linux/delay.h>
36 #include <linux/mutex.h>
37
38 #include <asm/irq.h>
39 #include <asm/uaccess.h>
40
41 #undef  DEBUG
42 #ifdef DEBUG
43 #define DPRINTK(x...)   printk(x)
44 #else
45 #define DPRINTK(x...)   do { } while (0)
46 #endif
47
48 /*
49  * This is used to lock changes in serial line configuration.
50  */
51 static DEFINE_MUTEX(port_mutex);
52
53 #define HIGH_BITS_OFFSET        ((sizeof(long)-sizeof(int))*8)
54
55 #define uart_users(state)       ((state)->count + ((state)->info ? (state)->info->blocked_open : 0))
56
57 #ifdef CONFIG_SERIAL_CORE_CONSOLE
58 #define uart_console(port)      ((port)->cons && (port)->cons->index == (port)->line)
59 #else
60 #define uart_console(port)      (0)
61 #endif
62
63 static void uart_change_speed(struct uart_state *state, struct termios *old_termios);
64 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
65 static void uart_change_pm(struct uart_state *state, int pm_state);
66
67 /*
68  * This routine is used by the interrupt handler to schedule processing in
69  * the software interrupt portion of the driver.
70  */
71 void uart_write_wakeup(struct uart_port *port)
72 {
73         struct uart_info *info = port->info;
74         tasklet_schedule(&info->tlet);
75 }
76
77 static void uart_stop(struct tty_struct *tty)
78 {
79         struct uart_state *state = tty->driver_data;
80         struct uart_port *port = state->port;
81         unsigned long flags;
82
83         spin_lock_irqsave(&port->lock, flags);
84         port->ops->stop_tx(port);
85         spin_unlock_irqrestore(&port->lock, flags);
86 }
87
88 static void __uart_start(struct tty_struct *tty)
89 {
90         struct uart_state *state = tty->driver_data;
91         struct uart_port *port = state->port;
92
93         if (!uart_circ_empty(&state->info->xmit) && state->info->xmit.buf &&
94             !tty->stopped && !tty->hw_stopped)
95                 port->ops->start_tx(port);
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         unsigned long flags;
103
104         spin_lock_irqsave(&port->lock, flags);
105         __uart_start(tty);
106         spin_unlock_irqrestore(&port->lock, flags);
107 }
108
109 static void uart_tasklet_action(unsigned long data)
110 {
111         struct uart_state *state = (struct uart_state *)data;
112         tty_wakeup(state->info->tty);
113 }
114
115 static inline void
116 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
117 {
118         unsigned long flags;
119         unsigned int old;
120
121         spin_lock_irqsave(&port->lock, flags);
122         old = port->mctrl;
123         port->mctrl = (old & ~clear) | set;
124         if (old != port->mctrl)
125                 port->ops->set_mctrl(port, port->mctrl);
126         spin_unlock_irqrestore(&port->lock, flags);
127 }
128
129 #define uart_set_mctrl(port,set)        uart_update_mctrl(port,set,0)
130 #define uart_clear_mctrl(port,clear)    uart_update_mctrl(port,0,clear)
131
132 /*
133  * Startup the port.  This will be called once per open.  All calls
134  * will be serialised by the per-port semaphore.
135  */
136 static int uart_startup(struct uart_state *state, int init_hw)
137 {
138         struct uart_info *info = state->info;
139         struct uart_port *port = state->port;
140         unsigned long page;
141         int retval = 0;
142
143         if (info->flags & UIF_INITIALIZED)
144                 return 0;
145
146         /*
147          * Set the TTY IO error marker - we will only clear this
148          * once we have successfully opened the port.  Also set
149          * up the tty->alt_speed kludge
150          */
151         set_bit(TTY_IO_ERROR, &info->tty->flags);
152
153         if (port->type == PORT_UNKNOWN)
154                 return 0;
155
156         /*
157          * Initialise and allocate the transmit and temporary
158          * buffer.
159          */
160         if (!info->xmit.buf) {
161                 page = get_zeroed_page(GFP_KERNEL);
162                 if (!page)
163                         return -ENOMEM;
164
165                 info->xmit.buf = (unsigned char *) page;
166                 uart_circ_clear(&info->xmit);
167         }
168
169         retval = port->ops->startup(port);
170         if (retval == 0) {
171                 if (init_hw) {
172                         /*
173                          * Initialise the hardware port settings.
174                          */
175                         uart_change_speed(state, NULL);
176
177                         /*
178                          * Setup the RTS and DTR signals once the
179                          * port is open and ready to respond.
180                          */
181                         if (info->tty->termios->c_cflag & CBAUD)
182                                 uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR);
183                 }
184
185                 if (info->flags & UIF_CTS_FLOW) {
186                         spin_lock_irq(&port->lock);
187                         if (!(port->ops->get_mctrl(port) & TIOCM_CTS))
188                                 info->tty->hw_stopped = 1;
189                         spin_unlock_irq(&port->lock);
190                 }
191
192                 info->flags |= UIF_INITIALIZED;
193
194                 clear_bit(TTY_IO_ERROR, &info->tty->flags);
195         }
196
197         if (retval && capable(CAP_SYS_ADMIN))
198                 retval = 0;
199
200         return retval;
201 }
202
203 /*
204  * This routine will shutdown a serial port; interrupts are disabled, and
205  * DTR is dropped if the hangup on close termio flag is on.  Calls to
206  * uart_shutdown are serialised by the per-port semaphore.
207  */
208 static void uart_shutdown(struct uart_state *state)
209 {
210         struct uart_info *info = state->info;
211         struct uart_port *port = state->port;
212
213         /*
214          * Set the TTY IO error marker
215          */
216         if (info->tty)
217                 set_bit(TTY_IO_ERROR, &info->tty->flags);
218
219         if (info->flags & UIF_INITIALIZED) {
220                 info->flags &= ~UIF_INITIALIZED;
221
222                 /*
223                  * Turn off DTR and RTS early.
224                  */
225                 if (!info->tty || (info->tty->termios->c_cflag & HUPCL))
226                         uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
227
228                 /*
229                  * clear delta_msr_wait queue to avoid mem leaks: we may free
230                  * the irq here so the queue might never be woken up.  Note
231                  * that we won't end up waiting on delta_msr_wait again since
232                  * any outstanding file descriptors should be pointing at
233                  * hung_up_tty_fops now.
234                  */
235                 wake_up_interruptible(&info->delta_msr_wait);
236
237                 /*
238                  * Free the IRQ and disable the port.
239                  */
240                 port->ops->shutdown(port);
241
242                 /*
243                  * Ensure that the IRQ handler isn't running on another CPU.
244                  */
245                 synchronize_irq(port->irq);
246         }
247
248         /*
249          * kill off our tasklet
250          */
251         tasklet_kill(&info->tlet);
252
253         /*
254          * Free the transmit buffer page.
255          */
256         if (info->xmit.buf) {
257                 free_page((unsigned long)info->xmit.buf);
258                 info->xmit.buf = NULL;
259         }
260 }
261
262 /**
263  *      uart_update_timeout - update per-port FIFO timeout.
264  *      @port:  uart_port structure describing the port
265  *      @cflag: termios cflag value
266  *      @baud:  speed of the port
267  *
268  *      Set the port FIFO timeout value.  The @cflag value should
269  *      reflect the actual hardware settings.
270  */
271 void
272 uart_update_timeout(struct uart_port *port, unsigned int cflag,
273                     unsigned int baud)
274 {
275         unsigned int bits;
276
277         /* byte size and parity */
278         switch (cflag & CSIZE) {
279         case CS5:
280                 bits = 7;
281                 break;
282         case CS6:
283                 bits = 8;
284                 break;
285         case CS7:
286                 bits = 9;
287                 break;
288         default:
289                 bits = 10;
290                 break; // CS8
291         }
292
293         if (cflag & CSTOPB)
294                 bits++;
295         if (cflag & PARENB)
296                 bits++;
297
298         /*
299          * The total number of bits to be transmitted in the fifo.
300          */
301         bits = bits * port->fifosize;
302
303         /*
304          * Figure the timeout to send the above number of bits.
305          * Add .02 seconds of slop
306          */
307         port->timeout = (HZ * bits) / baud + HZ/50;
308 }
309
310 EXPORT_SYMBOL(uart_update_timeout);
311
312 /**
313  *      uart_get_baud_rate - return baud rate for a particular port
314  *      @port: uart_port structure describing the port in question.
315  *      @termios: desired termios settings.
316  *      @old: old termios (or NULL)
317  *      @min: minimum acceptable baud rate
318  *      @max: maximum acceptable baud rate
319  *
320  *      Decode the termios structure into a numeric baud rate,
321  *      taking account of the magic 38400 baud rate (with spd_*
322  *      flags), and mapping the %B0 rate to 9600 baud.
323  *
324  *      If the new baud rate is invalid, try the old termios setting.
325  *      If it's still invalid, we try 9600 baud.
326  *
327  *      Update the @termios structure to reflect the baud rate
328  *      we're actually going to be using.
329  */
330 unsigned int
331 uart_get_baud_rate(struct uart_port *port, struct termios *termios,
332                    struct termios *old, unsigned int min, unsigned int max)
333 {
334         unsigned int try, baud, altbaud = 38400;
335         upf_t flags = port->flags & UPF_SPD_MASK;
336
337         if (flags == UPF_SPD_HI)
338                 altbaud = 57600;
339         if (flags == UPF_SPD_VHI)
340                 altbaud = 115200;
341         if (flags == UPF_SPD_SHI)
342                 altbaud = 230400;
343         if (flags == UPF_SPD_WARP)
344                 altbaud = 460800;
345
346         for (try = 0; try < 2; try++) {
347                 baud = tty_termios_baud_rate(termios);
348
349                 /*
350                  * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
351                  * Die! Die! Die!
352                  */
353                 if (baud == 38400)
354                         baud = altbaud;
355
356                 /*
357                  * Special case: B0 rate.
358                  */
359                 if (baud == 0)
360                         baud = 9600;
361
362                 if (baud >= min && baud <= max)
363                         return baud;
364
365                 /*
366                  * Oops, the quotient was zero.  Try again with
367                  * the old baud rate if possible.
368                  */
369                 termios->c_cflag &= ~CBAUD;
370                 if (old) {
371                         termios->c_cflag |= old->c_cflag & CBAUD;
372                         old = NULL;
373                         continue;
374                 }
375
376                 /*
377                  * As a last resort, if the quotient is zero,
378                  * default to 9600 bps
379                  */
380                 termios->c_cflag |= B9600;
381         }
382
383         return 0;
384 }
385
386 EXPORT_SYMBOL(uart_get_baud_rate);
387
388 /**
389  *      uart_get_divisor - return uart clock divisor
390  *      @port: uart_port structure describing the port.
391  *      @baud: desired baud rate
392  *
393  *      Calculate the uart clock divisor for the port.
394  */
395 unsigned int
396 uart_get_divisor(struct uart_port *port, unsigned int baud)
397 {
398         unsigned int quot;
399
400         /*
401          * Old custom speed handling.
402          */
403         if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
404                 quot = port->custom_divisor;
405         else
406                 quot = (port->uartclk + (8 * baud)) / (16 * baud);
407
408         return quot;
409 }
410
411 EXPORT_SYMBOL(uart_get_divisor);
412
413 static void
414 uart_change_speed(struct uart_state *state, struct termios *old_termios)
415 {
416         struct tty_struct *tty = state->info->tty;
417         struct uart_port *port = state->port;
418         struct termios *termios;
419
420         /*
421          * If we have no tty, termios, or the port does not exist,
422          * then we can't set the parameters for this port.
423          */
424         if (!tty || !tty->termios || port->type == PORT_UNKNOWN)
425                 return;
426
427         termios = tty->termios;
428
429         /*
430          * Set flags based on termios cflag
431          */
432         if (termios->c_cflag & CRTSCTS)
433                 state->info->flags |= UIF_CTS_FLOW;
434         else
435                 state->info->flags &= ~UIF_CTS_FLOW;
436
437         if (termios->c_cflag & CLOCAL)
438                 state->info->flags &= ~UIF_CHECK_CD;
439         else
440                 state->info->flags |= UIF_CHECK_CD;
441
442         port->ops->set_termios(port, termios, old_termios);
443 }
444
445 static inline void
446 __uart_put_char(struct uart_port *port, struct circ_buf *circ, unsigned char c)
447 {
448         unsigned long flags;
449
450         if (!circ->buf)
451                 return;
452
453         spin_lock_irqsave(&port->lock, flags);
454         if (uart_circ_chars_free(circ) != 0) {
455                 circ->buf[circ->head] = c;
456                 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
457         }
458         spin_unlock_irqrestore(&port->lock, flags);
459 }
460
461 static void uart_put_char(struct tty_struct *tty, unsigned char ch)
462 {
463         struct uart_state *state = tty->driver_data;
464
465         __uart_put_char(state->port, &state->info->xmit, ch);
466 }
467
468 static void uart_flush_chars(struct tty_struct *tty)
469 {
470         uart_start(tty);
471 }
472
473 static int
474 uart_write(struct tty_struct *tty, const unsigned char * buf, int count)
475 {
476         struct uart_state *state = tty->driver_data;
477         struct uart_port *port = state->port;
478         struct circ_buf *circ = &state->info->xmit;
479         unsigned long flags;
480         int c, ret = 0;
481
482         if (!circ->buf)
483                 return 0;
484
485         spin_lock_irqsave(&port->lock, flags);
486         while (1) {
487                 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
488                 if (count < c)
489                         c = count;
490                 if (c <= 0)
491                         break;
492                 memcpy(circ->buf + circ->head, buf, c);
493                 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
494                 buf += c;
495                 count -= c;
496                 ret += c;
497         }
498         spin_unlock_irqrestore(&port->lock, flags);
499
500         uart_start(tty);
501         return ret;
502 }
503
504 static int uart_write_room(struct tty_struct *tty)
505 {
506         struct uart_state *state = tty->driver_data;
507
508         return uart_circ_chars_free(&state->info->xmit);
509 }
510
511 static int uart_chars_in_buffer(struct tty_struct *tty)
512 {
513         struct uart_state *state = tty->driver_data;
514
515         return uart_circ_chars_pending(&state->info->xmit);
516 }
517
518 static void uart_flush_buffer(struct tty_struct *tty)
519 {
520         struct uart_state *state = tty->driver_data;
521         struct uart_port *port = state->port;
522         unsigned long flags;
523
524         DPRINTK("uart_flush_buffer(%d) called\n", tty->index);
525
526         spin_lock_irqsave(&port->lock, flags);
527         uart_circ_clear(&state->info->xmit);
528         spin_unlock_irqrestore(&port->lock, flags);
529         tty_wakeup(tty);
530 }
531
532 /*
533  * This function is used to send a high-priority XON/XOFF character to
534  * the device
535  */
536 static void uart_send_xchar(struct tty_struct *tty, char ch)
537 {
538         struct uart_state *state = tty->driver_data;
539         struct uart_port *port = state->port;
540         unsigned long flags;
541
542         if (port->ops->send_xchar)
543                 port->ops->send_xchar(port, ch);
544         else {
545                 port->x_char = ch;
546                 if (ch) {
547                         spin_lock_irqsave(&port->lock, flags);
548                         port->ops->start_tx(port);
549                         spin_unlock_irqrestore(&port->lock, flags);
550                 }
551         }
552 }
553
554 static void uart_throttle(struct tty_struct *tty)
555 {
556         struct uart_state *state = tty->driver_data;
557
558         if (I_IXOFF(tty))
559                 uart_send_xchar(tty, STOP_CHAR(tty));
560
561         if (tty->termios->c_cflag & CRTSCTS)
562                 uart_clear_mctrl(state->port, TIOCM_RTS);
563 }
564
565 static void uart_unthrottle(struct tty_struct *tty)
566 {
567         struct uart_state *state = tty->driver_data;
568         struct uart_port *port = state->port;
569
570         if (I_IXOFF(tty)) {
571                 if (port->x_char)
572                         port->x_char = 0;
573                 else
574                         uart_send_xchar(tty, START_CHAR(tty));
575         }
576
577         if (tty->termios->c_cflag & CRTSCTS)
578                 uart_set_mctrl(port, TIOCM_RTS);
579 }
580
581 static int uart_get_info(struct uart_state *state,
582                          struct serial_struct __user *retinfo)
583 {
584         struct uart_port *port = state->port;
585         struct serial_struct tmp;
586
587         memset(&tmp, 0, sizeof(tmp));
588         tmp.type            = port->type;
589         tmp.line            = port->line;
590         tmp.port            = port->iobase;
591         if (HIGH_BITS_OFFSET)
592                 tmp.port_high = (long) port->iobase >> HIGH_BITS_OFFSET;
593         tmp.irq             = port->irq;
594         tmp.flags           = port->flags;
595         tmp.xmit_fifo_size  = port->fifosize;
596         tmp.baud_base       = port->uartclk / 16;
597         tmp.close_delay     = state->close_delay / 10;
598         tmp.closing_wait    = state->closing_wait == USF_CLOSING_WAIT_NONE ?
599                                 ASYNC_CLOSING_WAIT_NONE :
600                                 state->closing_wait / 10;
601         tmp.custom_divisor  = port->custom_divisor;
602         tmp.hub6            = port->hub6;
603         tmp.io_type         = port->iotype;
604         tmp.iomem_reg_shift = port->regshift;
605         tmp.iomem_base      = (void *)port->mapbase;
606
607         if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
608                 return -EFAULT;
609         return 0;
610 }
611
612 static int uart_set_info(struct uart_state *state,
613                          struct serial_struct __user *newinfo)
614 {
615         struct serial_struct new_serial;
616         struct uart_port *port = state->port;
617         unsigned long new_port;
618         unsigned int change_irq, change_port, closing_wait;
619         unsigned int old_custom_divisor, close_delay;
620         upf_t old_flags, new_flags;
621         int retval = 0;
622
623         if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
624                 return -EFAULT;
625
626         new_port = new_serial.port;
627         if (HIGH_BITS_OFFSET)
628                 new_port += (unsigned long) new_serial.port_high << HIGH_BITS_OFFSET;
629
630         new_serial.irq = irq_canonicalize(new_serial.irq);
631         close_delay = new_serial.close_delay * 10;
632         closing_wait = new_serial.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
633                         USF_CLOSING_WAIT_NONE : new_serial.closing_wait * 10;
634
635         /*
636          * This semaphore protects state->count.  It is also
637          * very useful to prevent opens.  Also, take the
638          * port configuration semaphore to make sure that a
639          * module insertion/removal doesn't change anything
640          * under us.
641          */
642         mutex_lock(&state->mutex);
643
644         change_irq  = new_serial.irq != port->irq;
645
646         /*
647          * Since changing the 'type' of the port changes its resource
648          * allocations, we should treat type changes the same as
649          * IO port changes.
650          */
651         change_port = new_port != port->iobase ||
652                       (unsigned long)new_serial.iomem_base != port->mapbase ||
653                       new_serial.hub6 != port->hub6 ||
654                       new_serial.io_type != port->iotype ||
655                       new_serial.iomem_reg_shift != port->regshift ||
656                       new_serial.type != port->type;
657
658         old_flags = port->flags;
659         new_flags = new_serial.flags;
660         old_custom_divisor = port->custom_divisor;
661
662         if (!capable(CAP_SYS_ADMIN)) {
663                 retval = -EPERM;
664                 if (change_irq || change_port ||
665                     (new_serial.baud_base != port->uartclk / 16) ||
666                     (close_delay != state->close_delay) ||
667                     (closing_wait != state->closing_wait) ||
668                     (new_serial.xmit_fifo_size != port->fifosize) ||
669                     (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
670                         goto exit;
671                 port->flags = ((port->flags & ~UPF_USR_MASK) |
672                                (new_flags & UPF_USR_MASK));
673                 port->custom_divisor = new_serial.custom_divisor;
674                 goto check_and_exit;
675         }
676
677         /*
678          * Ask the low level driver to verify the settings.
679          */
680         if (port->ops->verify_port)
681                 retval = port->ops->verify_port(port, &new_serial);
682
683         if ((new_serial.irq >= NR_IRQS) || (new_serial.irq < 0) ||
684             (new_serial.baud_base < 9600))
685                 retval = -EINVAL;
686
687         if (retval)
688                 goto exit;
689
690         if (change_port || change_irq) {
691                 retval = -EBUSY;
692
693                 /*
694                  * Make sure that we are the sole user of this port.
695                  */
696                 if (uart_users(state) > 1)
697                         goto exit;
698
699                 /*
700                  * We need to shutdown the serial port at the old
701                  * port/type/irq combination.
702                  */
703                 uart_shutdown(state);
704         }
705
706         if (change_port) {
707                 unsigned long old_iobase, old_mapbase;
708                 unsigned int old_type, old_iotype, old_hub6, old_shift;
709
710                 old_iobase = port->iobase;
711                 old_mapbase = port->mapbase;
712                 old_type = port->type;
713                 old_hub6 = port->hub6;
714                 old_iotype = port->iotype;
715                 old_shift = port->regshift;
716
717                 /*
718                  * Free and release old regions
719                  */
720                 if (old_type != PORT_UNKNOWN)
721                         port->ops->release_port(port);
722
723                 port->iobase = new_port;
724                 port->type = new_serial.type;
725                 port->hub6 = new_serial.hub6;
726                 port->iotype = new_serial.io_type;
727                 port->regshift = new_serial.iomem_reg_shift;
728                 port->mapbase = (unsigned long)new_serial.iomem_base;
729
730                 /*
731                  * Claim and map the new regions
732                  */
733                 if (port->type != PORT_UNKNOWN) {
734                         retval = port->ops->request_port(port);
735                 } else {
736                         /* Always success - Jean II */
737                         retval = 0;
738                 }
739
740                 /*
741                  * If we fail to request resources for the
742                  * new port, try to restore the old settings.
743                  */
744                 if (retval && old_type != PORT_UNKNOWN) {
745                         port->iobase = old_iobase;
746                         port->type = old_type;
747                         port->hub6 = old_hub6;
748                         port->iotype = old_iotype;
749                         port->regshift = old_shift;
750                         port->mapbase = old_mapbase;
751                         retval = port->ops->request_port(port);
752                         /*
753                          * If we failed to restore the old settings,
754                          * we fail like this.
755                          */
756                         if (retval)
757                                 port->type = PORT_UNKNOWN;
758
759                         /*
760                          * We failed anyway.
761                          */
762                         retval = -EBUSY;
763                 }
764         }
765
766         port->irq              = new_serial.irq;
767         port->uartclk          = new_serial.baud_base * 16;
768         port->flags            = (port->flags & ~UPF_CHANGE_MASK) |
769                                  (new_flags & UPF_CHANGE_MASK);
770         port->custom_divisor   = new_serial.custom_divisor;
771         state->close_delay     = close_delay;
772         state->closing_wait    = closing_wait;
773         port->fifosize         = new_serial.xmit_fifo_size;
774         if (state->info->tty)
775                 state->info->tty->low_latency =
776                         (port->flags & UPF_LOW_LATENCY) ? 1 : 0;
777
778  check_and_exit:
779         retval = 0;
780         if (port->type == PORT_UNKNOWN)
781                 goto exit;
782         if (state->info->flags & UIF_INITIALIZED) {
783                 if (((old_flags ^ port->flags) & UPF_SPD_MASK) ||
784                     old_custom_divisor != port->custom_divisor) {
785                         /*
786                          * If they're setting up a custom divisor or speed,
787                          * instead of clearing it, then bitch about it. No
788                          * need to rate-limit; it's CAP_SYS_ADMIN only.
789                          */
790                         if (port->flags & UPF_SPD_MASK) {
791                                 char buf[64];
792                                 printk(KERN_NOTICE
793                                        "%s sets custom speed on %s. This "
794                                        "is deprecated.\n", current->comm,
795                                        tty_name(state->info->tty, buf));
796                         }
797                         uart_change_speed(state, NULL);
798                 }
799         } else
800                 retval = uart_startup(state, 1);
801  exit:
802         mutex_unlock(&state->mutex);
803         return retval;
804 }
805
806
807 /*
808  * uart_get_lsr_info - get line status register info.
809  * Note: uart_ioctl protects us against hangups.
810  */
811 static int uart_get_lsr_info(struct uart_state *state,
812                              unsigned int __user *value)
813 {
814         struct uart_port *port = state->port;
815         unsigned int result;
816
817         result = port->ops->tx_empty(port);
818
819         /*
820          * If we're about to load something into the transmit
821          * register, we'll pretend the transmitter isn't empty to
822          * avoid a race condition (depending on when the transmit
823          * interrupt happens).
824          */
825         if (port->x_char ||
826             ((uart_circ_chars_pending(&state->info->xmit) > 0) &&
827              !state->info->tty->stopped && !state->info->tty->hw_stopped))
828                 result &= ~TIOCSER_TEMT;
829         
830         return put_user(result, value);
831 }
832
833 static int uart_tiocmget(struct tty_struct *tty, struct file *file)
834 {
835         struct uart_state *state = tty->driver_data;
836         struct uart_port *port = state->port;
837         int result = -EIO;
838
839         mutex_lock(&state->mutex);
840         if ((!file || !tty_hung_up_p(file)) &&
841             !(tty->flags & (1 << TTY_IO_ERROR))) {
842                 result = port->mctrl;
843
844                 spin_lock_irq(&port->lock);
845                 result |= port->ops->get_mctrl(port);
846                 spin_unlock_irq(&port->lock);
847         }
848         mutex_unlock(&state->mutex);
849
850         return result;
851 }
852
853 static int
854 uart_tiocmset(struct tty_struct *tty, struct file *file,
855               unsigned int set, unsigned int clear)
856 {
857         struct uart_state *state = tty->driver_data;
858         struct uart_port *port = state->port;
859         int ret = -EIO;
860
861         mutex_lock(&state->mutex);
862         if ((!file || !tty_hung_up_p(file)) &&
863             !(tty->flags & (1 << TTY_IO_ERROR))) {
864                 uart_update_mctrl(port, set, clear);
865                 ret = 0;
866         }
867         mutex_unlock(&state->mutex);
868         return ret;
869 }
870
871 static void uart_break_ctl(struct tty_struct *tty, int break_state)
872 {
873         struct uart_state *state = tty->driver_data;
874         struct uart_port *port = state->port;
875
876         BUG_ON(!kernel_locked());
877
878         mutex_lock(&state->mutex);
879
880         if (port->type != PORT_UNKNOWN)
881                 port->ops->break_ctl(port, break_state);
882
883         mutex_unlock(&state->mutex);
884 }
885
886 static int uart_do_autoconfig(struct uart_state *state)
887 {
888         struct uart_port *port = state->port;
889         int flags, ret;
890
891         if (!capable(CAP_SYS_ADMIN))
892                 return -EPERM;
893
894         /*
895          * Take the per-port semaphore.  This prevents count from
896          * changing, and hence any extra opens of the port while
897          * we're auto-configuring.
898          */
899         if (mutex_lock_interruptible(&state->mutex))
900                 return -ERESTARTSYS;
901
902         ret = -EBUSY;
903         if (uart_users(state) == 1) {
904                 uart_shutdown(state);
905
906                 /*
907                  * If we already have a port type configured,
908                  * we must release its resources.
909                  */
910                 if (port->type != PORT_UNKNOWN)
911                         port->ops->release_port(port);
912
913                 flags = UART_CONFIG_TYPE;
914                 if (port->flags & UPF_AUTO_IRQ)
915                         flags |= UART_CONFIG_IRQ;
916
917                 /*
918                  * This will claim the ports resources if
919                  * a port is found.
920                  */
921                 port->ops->config_port(port, flags);
922
923                 ret = uart_startup(state, 1);
924         }
925         mutex_unlock(&state->mutex);
926         return ret;
927 }
928
929 /*
930  * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
931  * - mask passed in arg for lines of interest
932  *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
933  * Caller should use TIOCGICOUNT to see which one it was
934  */
935 static int
936 uart_wait_modem_status(struct uart_state *state, unsigned long arg)
937 {
938         struct uart_port *port = state->port;
939         DECLARE_WAITQUEUE(wait, current);
940         struct uart_icount cprev, cnow;
941         int ret;
942
943         /*
944          * note the counters on entry
945          */
946         spin_lock_irq(&port->lock);
947         memcpy(&cprev, &port->icount, sizeof(struct uart_icount));
948
949         /*
950          * Force modem status interrupts on
951          */
952         port->ops->enable_ms(port);
953         spin_unlock_irq(&port->lock);
954
955         add_wait_queue(&state->info->delta_msr_wait, &wait);
956         for (;;) {
957                 spin_lock_irq(&port->lock);
958                 memcpy(&cnow, &port->icount, sizeof(struct uart_icount));
959                 spin_unlock_irq(&port->lock);
960
961                 set_current_state(TASK_INTERRUPTIBLE);
962
963                 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
964                     ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
965                     ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
966                     ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
967                         ret = 0;
968                         break;
969                 }
970
971                 schedule();
972
973                 /* see if a signal did it */
974                 if (signal_pending(current)) {
975                         ret = -ERESTARTSYS;
976                         break;
977                 }
978
979                 cprev = cnow;
980         }
981
982         current->state = TASK_RUNNING;
983         remove_wait_queue(&state->info->delta_msr_wait, &wait);
984
985         return ret;
986 }
987
988 /*
989  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
990  * Return: write counters to the user passed counter struct
991  * NB: both 1->0 and 0->1 transitions are counted except for
992  *     RI where only 0->1 is counted.
993  */
994 static int uart_get_count(struct uart_state *state,
995                           struct serial_icounter_struct __user *icnt)
996 {
997         struct serial_icounter_struct icount;
998         struct uart_icount cnow;
999         struct uart_port *port = state->port;
1000
1001         spin_lock_irq(&port->lock);
1002         memcpy(&cnow, &port->icount, sizeof(struct uart_icount));
1003         spin_unlock_irq(&port->lock);
1004
1005         icount.cts         = cnow.cts;
1006         icount.dsr         = cnow.dsr;
1007         icount.rng         = cnow.rng;
1008         icount.dcd         = cnow.dcd;
1009         icount.rx          = cnow.rx;
1010         icount.tx          = cnow.tx;
1011         icount.frame       = cnow.frame;
1012         icount.overrun     = cnow.overrun;
1013         icount.parity      = cnow.parity;
1014         icount.brk         = cnow.brk;
1015         icount.buf_overrun = cnow.buf_overrun;
1016
1017         return copy_to_user(icnt, &icount, sizeof(icount)) ? -EFAULT : 0;
1018 }
1019
1020 /*
1021  * Called via sys_ioctl under the BKL.  We can use spin_lock_irq() here.
1022  */
1023 static int
1024 uart_ioctl(struct tty_struct *tty, struct file *filp, unsigned int cmd,
1025            unsigned long arg)
1026 {
1027         struct uart_state *state = tty->driver_data;
1028         void __user *uarg = (void __user *)arg;
1029         int ret = -ENOIOCTLCMD;
1030
1031         BUG_ON(!kernel_locked());
1032
1033         /*
1034          * These ioctls don't rely on the hardware to be present.
1035          */
1036         switch (cmd) {
1037         case TIOCGSERIAL:
1038                 ret = uart_get_info(state, uarg);
1039                 break;
1040
1041         case TIOCSSERIAL:
1042                 ret = uart_set_info(state, uarg);
1043                 break;
1044
1045         case TIOCSERCONFIG:
1046                 ret = uart_do_autoconfig(state);
1047                 break;
1048
1049         case TIOCSERGWILD: /* obsolete */
1050         case TIOCSERSWILD: /* obsolete */
1051                 ret = 0;
1052                 break;
1053         }
1054
1055         if (ret != -ENOIOCTLCMD)
1056                 goto out;
1057
1058         if (tty->flags & (1 << TTY_IO_ERROR)) {
1059                 ret = -EIO;
1060                 goto out;
1061         }
1062
1063         /*
1064          * The following should only be used when hardware is present.
1065          */
1066         switch (cmd) {
1067         case TIOCMIWAIT:
1068                 ret = uart_wait_modem_status(state, arg);
1069                 break;
1070
1071         case TIOCGICOUNT:
1072                 ret = uart_get_count(state, uarg);
1073                 break;
1074         }
1075
1076         if (ret != -ENOIOCTLCMD)
1077                 goto out;
1078
1079         mutex_lock(&state->mutex);
1080
1081         if (tty_hung_up_p(filp)) {
1082                 ret = -EIO;
1083                 goto out_up;
1084         }
1085
1086         /*
1087          * All these rely on hardware being present and need to be
1088          * protected against the tty being hung up.
1089          */
1090         switch (cmd) {
1091         case TIOCSERGETLSR: /* Get line status register */
1092                 ret = uart_get_lsr_info(state, uarg);
1093                 break;
1094
1095         default: {
1096                 struct uart_port *port = state->port;
1097                 if (port->ops->ioctl)
1098                         ret = port->ops->ioctl(port, cmd, arg);
1099                 break;
1100         }
1101         }
1102  out_up:
1103         mutex_unlock(&state->mutex);
1104  out:
1105         return ret;
1106 }
1107
1108 static void uart_set_termios(struct tty_struct *tty, struct termios *old_termios)
1109 {
1110         struct uart_state *state = tty->driver_data;
1111         unsigned long flags;
1112         unsigned int cflag = tty->termios->c_cflag;
1113
1114         BUG_ON(!kernel_locked());
1115
1116         /*
1117          * These are the bits that are used to setup various
1118          * flags in the low level driver.
1119          */
1120 #define RELEVANT_IFLAG(iflag)   ((iflag) & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))
1121
1122         if ((cflag ^ old_termios->c_cflag) == 0 &&
1123             RELEVANT_IFLAG(tty->termios->c_iflag ^ old_termios->c_iflag) == 0)
1124                 return;
1125
1126         uart_change_speed(state, old_termios);
1127
1128         /* Handle transition to B0 status */
1129         if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1130                 uart_clear_mctrl(state->port, TIOCM_RTS | TIOCM_DTR);
1131
1132         /* Handle transition away from B0 status */
1133         if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1134                 unsigned int mask = TIOCM_DTR;
1135                 if (!(cflag & CRTSCTS) ||
1136                     !test_bit(TTY_THROTTLED, &tty->flags))
1137                         mask |= TIOCM_RTS;
1138                 uart_set_mctrl(state->port, mask);
1139         }
1140
1141         /* Handle turning off CRTSCTS */
1142         if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {
1143                 spin_lock_irqsave(&state->port->lock, flags);
1144                 tty->hw_stopped = 0;
1145                 __uart_start(tty);
1146                 spin_unlock_irqrestore(&state->port->lock, flags);
1147         }
1148
1149         /* Handle turning on CRTSCTS */
1150         if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {
1151                 spin_lock_irqsave(&state->port->lock, flags);
1152                 if (!(state->port->ops->get_mctrl(state->port) & TIOCM_CTS)) {
1153                         tty->hw_stopped = 1;
1154                         state->port->ops->stop_tx(state->port);
1155                 }
1156                 spin_unlock_irqrestore(&state->port->lock, flags);
1157         }
1158
1159 #if 0
1160         /*
1161          * No need to wake up processes in open wait, since they
1162          * sample the CLOCAL flag once, and don't recheck it.
1163          * XXX  It's not clear whether the current behavior is correct
1164          * or not.  Hence, this may change.....
1165          */
1166         if (!(old_termios->c_cflag & CLOCAL) &&
1167             (tty->termios->c_cflag & CLOCAL))
1168                 wake_up_interruptible(&state->info->open_wait);
1169 #endif
1170 }
1171
1172 /*
1173  * In 2.4.5, calls to this will be serialized via the BKL in
1174  *  linux/drivers/char/tty_io.c:tty_release()
1175  *  linux/drivers/char/tty_io.c:do_tty_handup()
1176  */
1177 static void uart_close(struct tty_struct *tty, struct file *filp)
1178 {
1179         struct uart_state *state = tty->driver_data;
1180         struct uart_port *port;
1181         
1182         BUG_ON(!kernel_locked());
1183
1184         if (!state || !state->port)
1185                 return;
1186
1187         port = state->port;
1188
1189         DPRINTK("uart_close(%d) called\n", port->line);
1190
1191         mutex_lock(&state->mutex);
1192
1193         if (tty_hung_up_p(filp))
1194                 goto done;
1195
1196         if ((tty->count == 1) && (state->count != 1)) {
1197                 /*
1198                  * Uh, oh.  tty->count is 1, which means that the tty
1199                  * structure will be freed.  state->count should always
1200                  * be one in these conditions.  If it's greater than
1201                  * one, we've got real problems, since it means the
1202                  * serial port won't be shutdown.
1203                  */
1204                 printk(KERN_ERR "uart_close: bad serial port count; tty->count is 1, "
1205                        "state->count is %d\n", state->count);
1206                 state->count = 1;
1207         }
1208         if (--state->count < 0) {
1209                 printk(KERN_ERR "uart_close: bad serial port count for %s: %d\n",
1210                        tty->name, state->count);
1211                 state->count = 0;
1212         }
1213         if (state->count)
1214                 goto done;
1215
1216         /*
1217          * Now we wait for the transmit buffer to clear; and we notify
1218          * the line discipline to only process XON/XOFF characters by
1219          * setting tty->closing.
1220          */
1221         tty->closing = 1;
1222
1223         if (state->closing_wait != USF_CLOSING_WAIT_NONE)
1224                 tty_wait_until_sent(tty, msecs_to_jiffies(state->closing_wait));
1225
1226         /*
1227          * At this point, we stop accepting input.  To do this, we
1228          * disable the receive line status interrupts.
1229          */
1230         if (state->info->flags & UIF_INITIALIZED) {
1231                 unsigned long flags;
1232                 spin_lock_irqsave(&port->lock, flags);
1233                 port->ops->stop_rx(port);
1234                 spin_unlock_irqrestore(&port->lock, flags);
1235                 /*
1236                  * Before we drop DTR, make sure the UART transmitter
1237                  * has completely drained; this is especially
1238                  * important if there is a transmit FIFO!
1239                  */
1240                 uart_wait_until_sent(tty, port->timeout);
1241         }
1242
1243         uart_shutdown(state);
1244         uart_flush_buffer(tty);
1245
1246         tty_ldisc_flush(tty);   
1247         
1248         tty->closing = 0;
1249         state->info->tty = NULL;
1250
1251         if (state->info->blocked_open) {
1252                 if (state->close_delay)
1253                         msleep_interruptible(state->close_delay);
1254         } else if (!uart_console(port)) {
1255                 uart_change_pm(state, 3);
1256         }
1257
1258         /*
1259          * Wake up anyone trying to open this port.
1260          */
1261         state->info->flags &= ~UIF_NORMAL_ACTIVE;
1262         wake_up_interruptible(&state->info->open_wait);
1263
1264  done:
1265         mutex_unlock(&state->mutex);
1266 }
1267
1268 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1269 {
1270         struct uart_state *state = tty->driver_data;
1271         struct uart_port *port = state->port;
1272         unsigned long char_time, expire;
1273
1274         BUG_ON(!kernel_locked());
1275
1276         if (port->type == PORT_UNKNOWN || port->fifosize == 0)
1277                 return;
1278
1279         /*
1280          * Set the check interval to be 1/5 of the estimated time to
1281          * send a single character, and make it at least 1.  The check
1282          * interval should also be less than the timeout.
1283          *
1284          * Note: we have to use pretty tight timings here to satisfy
1285          * the NIST-PCTS.
1286          */
1287         char_time = (port->timeout - HZ/50) / port->fifosize;
1288         char_time = char_time / 5;
1289         if (char_time == 0)
1290                 char_time = 1;
1291         if (timeout && timeout < char_time)
1292                 char_time = timeout;
1293
1294         /*
1295          * If the transmitter hasn't cleared in twice the approximate
1296          * amount of time to send the entire FIFO, it probably won't
1297          * ever clear.  This assumes the UART isn't doing flow
1298          * control, which is currently the case.  Hence, if it ever
1299          * takes longer than port->timeout, this is probably due to a
1300          * UART bug of some kind.  So, we clamp the timeout parameter at
1301          * 2*port->timeout.
1302          */
1303         if (timeout == 0 || timeout > 2 * port->timeout)
1304                 timeout = 2 * port->timeout;
1305
1306         expire = jiffies + timeout;
1307
1308         DPRINTK("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1309                 port->line, jiffies, expire);
1310
1311         /*
1312          * Check whether the transmitter is empty every 'char_time'.
1313          * 'timeout' / 'expire' give us the maximum amount of time
1314          * we wait.
1315          */
1316         while (!port->ops->tx_empty(port)) {
1317                 msleep_interruptible(jiffies_to_msecs(char_time));
1318                 if (signal_pending(current))
1319                         break;
1320                 if (time_after(jiffies, expire))
1321                         break;
1322         }
1323         set_current_state(TASK_RUNNING); /* might not be needed */
1324 }
1325
1326 /*
1327  * This is called with the BKL held in
1328  *  linux/drivers/char/tty_io.c:do_tty_hangup()
1329  * We're called from the eventd thread, so we can sleep for
1330  * a _short_ time only.
1331  */
1332 static void uart_hangup(struct tty_struct *tty)
1333 {
1334         struct uart_state *state = tty->driver_data;
1335
1336         BUG_ON(!kernel_locked());
1337         DPRINTK("uart_hangup(%d)\n", state->port->line);
1338
1339         mutex_lock(&state->mutex);
1340         if (state->info && state->info->flags & UIF_NORMAL_ACTIVE) {
1341                 uart_flush_buffer(tty);
1342                 uart_shutdown(state);
1343                 state->count = 0;
1344                 state->info->flags &= ~UIF_NORMAL_ACTIVE;
1345                 state->info->tty = NULL;
1346                 wake_up_interruptible(&state->info->open_wait);
1347                 wake_up_interruptible(&state->info->delta_msr_wait);
1348         }
1349         mutex_unlock(&state->mutex);
1350 }
1351
1352 /*
1353  * Copy across the serial console cflag setting into the termios settings
1354  * for the initial open of the port.  This allows continuity between the
1355  * kernel settings, and the settings init adopts when it opens the port
1356  * for the first time.
1357  */
1358 static void uart_update_termios(struct uart_state *state)
1359 {
1360         struct tty_struct *tty = state->info->tty;
1361         struct uart_port *port = state->port;
1362
1363         if (uart_console(port) && port->cons->cflag) {
1364                 tty->termios->c_cflag = port->cons->cflag;
1365                 port->cons->cflag = 0;
1366         }
1367
1368         /*
1369          * If the device failed to grab its irq resources,
1370          * or some other error occurred, don't try to talk
1371          * to the port hardware.
1372          */
1373         if (!(tty->flags & (1 << TTY_IO_ERROR))) {
1374                 /*
1375                  * Make termios settings take effect.
1376                  */
1377                 uart_change_speed(state, NULL);
1378
1379                 /*
1380                  * And finally enable the RTS and DTR signals.
1381                  */
1382                 if (tty->termios->c_cflag & CBAUD)
1383                         uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS);
1384         }
1385 }
1386
1387 /*
1388  * Block the open until the port is ready.  We must be called with
1389  * the per-port semaphore held.
1390  */
1391 static int
1392 uart_block_til_ready(struct file *filp, struct uart_state *state)
1393 {
1394         DECLARE_WAITQUEUE(wait, current);
1395         struct uart_info *info = state->info;
1396         struct uart_port *port = state->port;
1397         unsigned int mctrl;
1398
1399         info->blocked_open++;
1400         state->count--;
1401
1402         add_wait_queue(&info->open_wait, &wait);
1403         while (1) {
1404                 set_current_state(TASK_INTERRUPTIBLE);
1405
1406                 /*
1407                  * If we have been hung up, tell userspace/restart open.
1408                  */
1409                 if (tty_hung_up_p(filp) || info->tty == NULL)
1410                         break;
1411
1412                 /*
1413                  * If the port has been closed, tell userspace/restart open.
1414                  */
1415                 if (!(info->flags & UIF_INITIALIZED))
1416                         break;
1417
1418                 /*
1419                  * If non-blocking mode is set, or CLOCAL mode is set,
1420                  * we don't want to wait for the modem status lines to
1421                  * indicate that the port is ready.
1422                  *
1423                  * Also, if the port is not enabled/configured, we want
1424                  * to allow the open to succeed here.  Note that we will
1425                  * have set TTY_IO_ERROR for a non-existant port.
1426                  */
1427                 if ((filp->f_flags & O_NONBLOCK) ||
1428                     (info->tty->termios->c_cflag & CLOCAL) ||
1429                     (info->tty->flags & (1 << TTY_IO_ERROR))) {
1430                         break;
1431                 }
1432
1433                 /*
1434                  * Set DTR to allow modem to know we're waiting.  Do
1435                  * not set RTS here - we want to make sure we catch
1436                  * the data from the modem.
1437                  */
1438                 if (info->tty->termios->c_cflag & CBAUD)
1439                         uart_set_mctrl(port, TIOCM_DTR);
1440
1441                 /*
1442                  * and wait for the carrier to indicate that the
1443                  * modem is ready for us.
1444                  */
1445                 spin_lock_irq(&port->lock);
1446                 port->ops->enable_ms(port);
1447                 mctrl = port->ops->get_mctrl(port);
1448                 spin_unlock_irq(&port->lock);
1449                 if (mctrl & TIOCM_CAR)
1450                         break;
1451
1452                 mutex_unlock(&state->mutex);
1453                 schedule();
1454                 mutex_lock(&state->mutex);
1455
1456                 if (signal_pending(current))
1457                         break;
1458         }
1459         set_current_state(TASK_RUNNING);
1460         remove_wait_queue(&info->open_wait, &wait);
1461
1462         state->count++;
1463         info->blocked_open--;
1464
1465         if (signal_pending(current))
1466                 return -ERESTARTSYS;
1467
1468         if (!info->tty || tty_hung_up_p(filp))
1469                 return -EAGAIN;
1470
1471         return 0;
1472 }
1473
1474 static struct uart_state *uart_get(struct uart_driver *drv, int line)
1475 {
1476         struct uart_state *state;
1477
1478         mutex_lock(&port_mutex);
1479         state = drv->state + line;
1480         if (mutex_lock_interruptible(&state->mutex)) {
1481                 state = ERR_PTR(-ERESTARTSYS);
1482                 goto out;
1483         }
1484
1485         state->count++;
1486         if (!state->port) {
1487                 state->count--;
1488                 mutex_unlock(&state->mutex);
1489                 state = ERR_PTR(-ENXIO);
1490                 goto out;
1491         }
1492
1493         if (!state->info) {
1494                 state->info = kmalloc(sizeof(struct uart_info), GFP_KERNEL);
1495                 if (state->info) {
1496                         memset(state->info, 0, sizeof(struct uart_info));
1497                         init_waitqueue_head(&state->info->open_wait);
1498                         init_waitqueue_head(&state->info->delta_msr_wait);
1499
1500                         /*
1501                          * Link the info into the other structures.
1502                          */
1503                         state->port->info = state->info;
1504
1505                         tasklet_init(&state->info->tlet, uart_tasklet_action,
1506                                      (unsigned long)state);
1507                 } else {
1508                         state->count--;
1509                         mutex_unlock(&state->mutex);
1510                         state = ERR_PTR(-ENOMEM);
1511                 }
1512         }
1513
1514  out:
1515         mutex_unlock(&port_mutex);
1516         return state;
1517 }
1518
1519 /*
1520  * In 2.4.5, calls to uart_open are serialised by the BKL in
1521  *   linux/fs/devices.c:chrdev_open()
1522  * Note that if this fails, then uart_close() _will_ be called.
1523  *
1524  * In time, we want to scrap the "opening nonpresent ports"
1525  * behaviour and implement an alternative way for setserial
1526  * to set base addresses/ports/types.  This will allow us to
1527  * get rid of a certain amount of extra tests.
1528  */
1529 static int uart_open(struct tty_struct *tty, struct file *filp)
1530 {
1531         struct uart_driver *drv = (struct uart_driver *)tty->driver->driver_state;
1532         struct uart_state *state;
1533         int retval, line = tty->index;
1534
1535         BUG_ON(!kernel_locked());
1536         DPRINTK("uart_open(%d) called\n", line);
1537
1538         /*
1539          * tty->driver->num won't change, so we won't fail here with
1540          * tty->driver_data set to something non-NULL (and therefore
1541          * we won't get caught by uart_close()).
1542          */
1543         retval = -ENODEV;
1544         if (line >= tty->driver->num)
1545                 goto fail;
1546
1547         /*
1548          * We take the semaphore inside uart_get to guarantee that we won't
1549          * be re-entered while allocating the info structure, or while we
1550          * request any IRQs that the driver may need.  This also has the nice
1551          * side-effect that it delays the action of uart_hangup, so we can
1552          * guarantee that info->tty will always contain something reasonable.
1553          */
1554         state = uart_get(drv, line);
1555         if (IS_ERR(state)) {
1556                 retval = PTR_ERR(state);
1557                 goto fail;
1558         }
1559
1560         /*
1561          * Once we set tty->driver_data here, we are guaranteed that
1562          * uart_close() will decrement the driver module use count.
1563          * Any failures from here onwards should not touch the count.
1564          */
1565         tty->driver_data = state;
1566         tty->low_latency = (state->port->flags & UPF_LOW_LATENCY) ? 1 : 0;
1567         tty->alt_speed = 0;
1568         state->info->tty = tty;
1569
1570         /*
1571          * If the port is in the middle of closing, bail out now.
1572          */
1573         if (tty_hung_up_p(filp)) {
1574                 retval = -EAGAIN;
1575                 state->count--;
1576                 mutex_unlock(&state->mutex);
1577                 goto fail;
1578         }
1579
1580         /*
1581          * Make sure the device is in D0 state.
1582          */
1583         if (state->count == 1)
1584                 uart_change_pm(state, 0);
1585
1586         /*
1587          * Start up the serial port.
1588          */
1589         retval = uart_startup(state, 0);
1590
1591         /*
1592          * If we succeeded, wait until the port is ready.
1593          */
1594         if (retval == 0)
1595                 retval = uart_block_til_ready(filp, state);
1596         mutex_unlock(&state->mutex);
1597
1598         /*
1599          * If this is the first open to succeed, adjust things to suit.
1600          */
1601         if (retval == 0 && !(state->info->flags & UIF_NORMAL_ACTIVE)) {
1602                 state->info->flags |= UIF_NORMAL_ACTIVE;
1603
1604                 uart_update_termios(state);
1605         }
1606
1607  fail:
1608         return retval;
1609 }
1610
1611 static const char *uart_type(struct uart_port *port)
1612 {
1613         const char *str = NULL;
1614
1615         if (port->ops->type)
1616                 str = port->ops->type(port);
1617
1618         if (!str)
1619                 str = "unknown";
1620
1621         return str;
1622 }
1623
1624 #ifdef CONFIG_PROC_FS
1625
1626 static int uart_line_info(char *buf, struct uart_driver *drv, int i)
1627 {
1628         struct uart_state *state = drv->state + i;
1629         struct uart_port *port = state->port;
1630         char stat_buf[32];
1631         unsigned int status;
1632         int ret;
1633
1634         if (!port)
1635                 return 0;
1636
1637         ret = sprintf(buf, "%d: uart:%s %s%08lX irq:%d",
1638                         port->line, uart_type(port),
1639                         port->iotype == UPIO_MEM ? "mmio:0x" : "port:",
1640                         port->iotype == UPIO_MEM ? port->mapbase :
1641                                                 (unsigned long) port->iobase,
1642                         port->irq);
1643
1644         if (port->type == PORT_UNKNOWN) {
1645                 strcat(buf, "\n");
1646                 return ret + 1;
1647         }
1648
1649         if(capable(CAP_SYS_ADMIN))
1650         {
1651                 spin_lock_irq(&port->lock);
1652                 status = port->ops->get_mctrl(port);
1653                 spin_unlock_irq(&port->lock);
1654
1655                 ret += sprintf(buf + ret, " tx:%d rx:%d",
1656                                 port->icount.tx, port->icount.rx);
1657                 if (port->icount.frame)
1658                         ret += sprintf(buf + ret, " fe:%d",
1659                                 port->icount.frame);
1660                 if (port->icount.parity)
1661                         ret += sprintf(buf + ret, " pe:%d",
1662                                 port->icount.parity);
1663                 if (port->icount.brk)
1664                         ret += sprintf(buf + ret, " brk:%d",
1665                                 port->icount.brk);
1666                 if (port->icount.overrun)
1667                         ret += sprintf(buf + ret, " oe:%d",
1668                                 port->icount.overrun);
1669         
1670 #define INFOBIT(bit,str) \
1671         if (port->mctrl & (bit)) \
1672                 strncat(stat_buf, (str), sizeof(stat_buf) - \
1673                         strlen(stat_buf) - 2)
1674 #define STATBIT(bit,str) \
1675         if (status & (bit)) \
1676                 strncat(stat_buf, (str), sizeof(stat_buf) - \
1677                        strlen(stat_buf) - 2)
1678
1679                 stat_buf[0] = '\0';
1680                 stat_buf[1] = '\0';
1681                 INFOBIT(TIOCM_RTS, "|RTS");
1682                 STATBIT(TIOCM_CTS, "|CTS");
1683                 INFOBIT(TIOCM_DTR, "|DTR");
1684                 STATBIT(TIOCM_DSR, "|DSR");
1685                 STATBIT(TIOCM_CAR, "|CD");
1686                 STATBIT(TIOCM_RNG, "|RI");
1687                 if (stat_buf[0])
1688                         stat_buf[0] = ' ';
1689                 strcat(stat_buf, "\n");
1690         
1691                 ret += sprintf(buf + ret, stat_buf);
1692         } else {
1693                 strcat(buf, "\n");
1694                 ret++;
1695         }
1696 #undef STATBIT
1697 #undef INFOBIT
1698         return ret;
1699 }
1700
1701 static int uart_read_proc(char *page, char **start, off_t off,
1702                           int count, int *eof, void *data)
1703 {
1704         struct tty_driver *ttydrv = data;
1705         struct uart_driver *drv = ttydrv->driver_state;
1706         int i, len = 0, l;
1707         off_t begin = 0;
1708
1709         len += sprintf(page, "serinfo:1.0 driver%s%s revision:%s\n",
1710                         "", "", "");
1711         for (i = 0; i < drv->nr && len < PAGE_SIZE - 96; i++) {
1712                 l = uart_line_info(page + len, drv, i);
1713                 len += l;
1714                 if (len + begin > off + count)
1715                         goto done;
1716                 if (len + begin < off) {
1717                         begin += len;
1718                         len = 0;
1719                 }
1720         }
1721         *eof = 1;
1722  done:
1723         if (off >= len + begin)
1724                 return 0;
1725         *start = page + (off - begin);
1726         return (count < begin + len - off) ? count : (begin + len - off);
1727 }
1728 #endif
1729
1730 #ifdef CONFIG_SERIAL_CORE_CONSOLE
1731 /*
1732  *      Check whether an invalid uart number has been specified, and
1733  *      if so, search for the first available port that does have
1734  *      console support.
1735  */
1736 struct uart_port * __init
1737 uart_get_console(struct uart_port *ports, int nr, struct console *co)
1738 {
1739         int idx = co->index;
1740
1741         if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
1742                                      ports[idx].membase == NULL))
1743                 for (idx = 0; idx < nr; idx++)
1744                         if (ports[idx].iobase != 0 ||
1745                             ports[idx].membase != NULL)
1746                                 break;
1747
1748         co->index = idx;
1749
1750         return ports + idx;
1751 }
1752
1753 /**
1754  *      uart_parse_options - Parse serial port baud/parity/bits/flow contro.
1755  *      @options: pointer to option string
1756  *      @baud: pointer to an 'int' variable for the baud rate.
1757  *      @parity: pointer to an 'int' variable for the parity.
1758  *      @bits: pointer to an 'int' variable for the number of data bits.
1759  *      @flow: pointer to an 'int' variable for the flow control character.
1760  *
1761  *      uart_parse_options decodes a string containing the serial console
1762  *      options.  The format of the string is <baud><parity><bits><flow>,
1763  *      eg: 115200n8r
1764  */
1765 void __init
1766 uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow)
1767 {
1768         char *s = options;
1769
1770         *baud = simple_strtoul(s, NULL, 10);
1771         while (*s >= '0' && *s <= '9')
1772                 s++;
1773         if (*s)
1774                 *parity = *s++;
1775         if (*s)
1776                 *bits = *s++ - '0';
1777         if (*s)
1778                 *flow = *s;
1779 }
1780
1781 struct baud_rates {
1782         unsigned int rate;
1783         unsigned int cflag;
1784 };
1785
1786 static const struct baud_rates baud_rates[] = {
1787         { 921600, B921600 },
1788         { 460800, B460800 },
1789         { 230400, B230400 },
1790         { 115200, B115200 },
1791         {  57600, B57600  },
1792         {  38400, B38400  },
1793         {  19200, B19200  },
1794         {   9600, B9600   },
1795         {   4800, B4800   },
1796         {   2400, B2400   },
1797         {   1200, B1200   },
1798         {      0, B38400  }
1799 };
1800
1801 /**
1802  *      uart_set_options - setup the serial console parameters
1803  *      @port: pointer to the serial ports uart_port structure
1804  *      @co: console pointer
1805  *      @baud: baud rate
1806  *      @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
1807  *      @bits: number of data bits
1808  *      @flow: flow control character - 'r' (rts)
1809  */
1810 int __init
1811 uart_set_options(struct uart_port *port, struct console *co,
1812                  int baud, int parity, int bits, int flow)
1813 {
1814         struct termios termios;
1815         int i;
1816
1817         /*
1818          * Ensure that the serial console lock is initialised
1819          * early.
1820          */
1821         spin_lock_init(&port->lock);
1822
1823         memset(&termios, 0, sizeof(struct termios));
1824
1825         termios.c_cflag = CREAD | HUPCL | CLOCAL;
1826
1827         /*
1828          * Construct a cflag setting.
1829          */
1830         for (i = 0; baud_rates[i].rate; i++)
1831                 if (baud_rates[i].rate <= baud)
1832                         break;
1833
1834         termios.c_cflag |= baud_rates[i].cflag;
1835
1836         if (bits == 7)
1837                 termios.c_cflag |= CS7;
1838         else
1839                 termios.c_cflag |= CS8;
1840
1841         switch (parity) {
1842         case 'o': case 'O':
1843                 termios.c_cflag |= PARODD;
1844                 /*fall through*/
1845         case 'e': case 'E':
1846                 termios.c_cflag |= PARENB;
1847                 break;
1848         }
1849
1850         if (flow == 'r')
1851                 termios.c_cflag |= CRTSCTS;
1852
1853         port->ops->set_termios(port, &termios, NULL);
1854         co->cflag = termios.c_cflag;
1855
1856         return 0;
1857 }
1858 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
1859
1860 static void uart_change_pm(struct uart_state *state, int pm_state)
1861 {
1862         struct uart_port *port = state->port;
1863         if (port->ops->pm)
1864                 port->ops->pm(port, pm_state, state->pm_state);
1865         state->pm_state = pm_state;
1866 }
1867
1868 int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
1869 {
1870         struct uart_state *state = drv->state + port->line;
1871
1872         mutex_lock(&state->mutex);
1873
1874         if (state->info && state->info->flags & UIF_INITIALIZED) {
1875                 const struct uart_ops *ops = port->ops;
1876
1877                 spin_lock_irq(&port->lock);
1878                 ops->stop_tx(port);
1879                 ops->set_mctrl(port, 0);
1880                 ops->stop_rx(port);
1881                 spin_unlock_irq(&port->lock);
1882
1883                 /*
1884                  * Wait for the transmitter to empty.
1885                  */
1886                 while (!ops->tx_empty(port)) {
1887                         msleep(10);
1888                 }
1889
1890                 ops->shutdown(port);
1891         }
1892
1893         /*
1894          * Disable the console device before suspending.
1895          */
1896         if (uart_console(port))
1897                 console_stop(port->cons);
1898
1899         uart_change_pm(state, 3);
1900
1901         mutex_unlock(&state->mutex);
1902
1903         return 0;
1904 }
1905
1906 int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
1907 {
1908         struct uart_state *state = drv->state + port->line;
1909
1910         mutex_lock(&state->mutex);
1911
1912         uart_change_pm(state, 0);
1913
1914         /*
1915          * Re-enable the console device after suspending.
1916          */
1917         if (uart_console(port)) {
1918                 struct termios termios;
1919
1920                 /*
1921                  * First try to use the console cflag setting.
1922                  */
1923                 memset(&termios, 0, sizeof(struct termios));
1924                 termios.c_cflag = port->cons->cflag;
1925
1926                 /*
1927                  * If that's unset, use the tty termios setting.
1928                  */
1929                 if (state->info && state->info->tty && termios.c_cflag == 0)
1930                         termios = *state->info->tty->termios;
1931
1932                 port->ops->set_termios(port, &termios, NULL);
1933                 console_start(port->cons);
1934         }
1935
1936         if (state->info && state->info->flags & UIF_INITIALIZED) {
1937                 const struct uart_ops *ops = port->ops;
1938                 int ret;
1939
1940                 ops->set_mctrl(port, 0);
1941                 ret = ops->startup(port);
1942                 if (ret == 0) {
1943                         uart_change_speed(state, NULL);
1944                         spin_lock_irq(&port->lock);
1945                         ops->set_mctrl(port, port->mctrl);
1946                         ops->start_tx(port);
1947                         spin_unlock_irq(&port->lock);
1948                 } else {
1949                         /*
1950                          * Failed to resume - maybe hardware went away?
1951                          * Clear the "initialized" flag so we won't try
1952                          * to call the low level drivers shutdown method.
1953                          */
1954                         state->info->flags &= ~UIF_INITIALIZED;
1955                         uart_shutdown(state);
1956                 }
1957         }
1958
1959         mutex_unlock(&state->mutex);
1960
1961         return 0;
1962 }
1963
1964 static inline void
1965 uart_report_port(struct uart_driver *drv, struct uart_port *port)
1966 {
1967         char address[64];
1968
1969         switch (port->iotype) {
1970         case UPIO_PORT:
1971                 snprintf(address, sizeof(address),
1972                          "I/O 0x%x", port->iobase);
1973                 break;
1974         case UPIO_HUB6:
1975                 snprintf(address, sizeof(address),
1976                          "I/O 0x%x offset 0x%x", port->iobase, port->hub6);
1977                 break;
1978         case UPIO_MEM:
1979         case UPIO_MEM32:
1980         case UPIO_AU:
1981                 snprintf(address, sizeof(address),
1982                          "MMIO 0x%lx", port->mapbase);
1983                 break;
1984         default:
1985                 strlcpy(address, "*unknown*", sizeof(address));
1986                 break;
1987         }
1988
1989         printk(KERN_INFO "%s%s%s%d at %s (irq = %d) is a %s\n",
1990                port->dev ? port->dev->bus_id : "",
1991                port->dev ? ": " : "",
1992                drv->dev_name, port->line, address, port->irq, uart_type(port));
1993 }
1994
1995 static void
1996 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
1997                     struct uart_port *port)
1998 {
1999         unsigned int flags;
2000
2001         /*
2002          * If there isn't a port here, don't do anything further.
2003          */
2004         if (!port->iobase && !port->mapbase && !port->membase)
2005                 return;
2006
2007         /*
2008          * Now do the auto configuration stuff.  Note that config_port
2009          * is expected to claim the resources and map the port for us.
2010          */
2011         flags = UART_CONFIG_TYPE;
2012         if (port->flags & UPF_AUTO_IRQ)
2013                 flags |= UART_CONFIG_IRQ;
2014         if (port->flags & UPF_BOOT_AUTOCONF) {
2015                 port->type = PORT_UNKNOWN;
2016                 port->ops->config_port(port, flags);
2017         }
2018
2019         if (port->type != PORT_UNKNOWN) {
2020                 unsigned long flags;
2021
2022                 uart_report_port(drv, port);
2023
2024                 /*
2025                  * Ensure that the modem control lines are de-activated.
2026                  * We probably don't need a spinlock around this, but
2027                  */
2028                 spin_lock_irqsave(&port->lock, flags);
2029                 port->ops->set_mctrl(port, 0);
2030                 spin_unlock_irqrestore(&port->lock, flags);
2031
2032                 /*
2033                  * Power down all ports by default, except the
2034                  * console if we have one.
2035                  */
2036                 if (!uart_console(port))
2037                         uart_change_pm(state, 3);
2038         }
2039 }
2040
2041 /*
2042  * This reverses the effects of uart_configure_port, hanging up the
2043  * port before removal.
2044  */
2045 static void
2046 uart_unconfigure_port(struct uart_driver *drv, struct uart_state *state)
2047 {
2048         struct uart_port *port = state->port;
2049         struct uart_info *info = state->info;
2050
2051         if (info && info->tty)
2052                 tty_vhangup(info->tty);
2053
2054         mutex_lock(&state->mutex);
2055
2056         state->info = NULL;
2057
2058         /*
2059          * Free the port IO and memory resources, if any.
2060          */
2061         if (port->type != PORT_UNKNOWN)
2062                 port->ops->release_port(port);
2063
2064         /*
2065          * Indicate that there isn't a port here anymore.
2066          */
2067         port->type = PORT_UNKNOWN;
2068
2069         /*
2070          * Kill the tasklet, and free resources.
2071          */
2072         if (info) {
2073                 tasklet_kill(&info->tlet);
2074                 kfree(info);
2075         }
2076
2077         mutex_unlock(&state->mutex);
2078 }
2079
2080 static struct tty_operations uart_ops = {
2081         .open           = uart_open,
2082         .close          = uart_close,
2083         .write          = uart_write,
2084         .put_char       = uart_put_char,
2085         .flush_chars    = uart_flush_chars,
2086         .write_room     = uart_write_room,
2087         .chars_in_buffer= uart_chars_in_buffer,
2088         .flush_buffer   = uart_flush_buffer,
2089         .ioctl          = uart_ioctl,
2090         .throttle       = uart_throttle,
2091         .unthrottle     = uart_unthrottle,
2092         .send_xchar     = uart_send_xchar,
2093         .set_termios    = uart_set_termios,
2094         .stop           = uart_stop,
2095         .start          = uart_start,
2096         .hangup         = uart_hangup,
2097         .break_ctl      = uart_break_ctl,
2098         .wait_until_sent= uart_wait_until_sent,
2099 #ifdef CONFIG_PROC_FS
2100         .read_proc      = uart_read_proc,
2101 #endif
2102         .tiocmget       = uart_tiocmget,
2103         .tiocmset       = uart_tiocmset,
2104 };
2105
2106 /**
2107  *      uart_register_driver - register a driver with the uart core layer
2108  *      @drv: low level driver structure
2109  *
2110  *      Register a uart driver with the core driver.  We in turn register
2111  *      with the tty layer, and initialise the core driver per-port state.
2112  *
2113  *      We have a proc file in /proc/tty/driver which is named after the
2114  *      normal driver.
2115  *
2116  *      drv->port should be NULL, and the per-port structures should be
2117  *      registered using uart_add_one_port after this call has succeeded.
2118  */
2119 int uart_register_driver(struct uart_driver *drv)
2120 {
2121         struct tty_driver *normal = NULL;
2122         int i, retval;
2123
2124         BUG_ON(drv->state);
2125
2126         /*
2127          * Maybe we should be using a slab cache for this, especially if
2128          * we have a large number of ports to handle.
2129          */
2130         drv->state = kmalloc(sizeof(struct uart_state) * drv->nr, GFP_KERNEL);
2131         retval = -ENOMEM;
2132         if (!drv->state)
2133                 goto out;
2134
2135         memset(drv->state, 0, sizeof(struct uart_state) * drv->nr);
2136
2137         normal  = alloc_tty_driver(drv->nr);
2138         if (!normal)
2139                 goto out;
2140
2141         drv->tty_driver = normal;
2142
2143         normal->owner           = drv->owner;
2144         normal->driver_name     = drv->driver_name;
2145         normal->devfs_name      = drv->devfs_name;
2146         normal->name            = drv->dev_name;
2147         normal->major           = drv->major;
2148         normal->minor_start     = drv->minor;
2149         normal->type            = TTY_DRIVER_TYPE_SERIAL;
2150         normal->subtype         = SERIAL_TYPE_NORMAL;
2151         normal->init_termios    = tty_std_termios;
2152         normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2153         normal->flags           = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
2154         normal->driver_state    = drv;
2155         tty_set_operations(normal, &uart_ops);
2156
2157         /*
2158          * Initialise the UART state(s).
2159          */
2160         for (i = 0; i < drv->nr; i++) {
2161                 struct uart_state *state = drv->state + i;
2162
2163                 state->close_delay     = 500;   /* .5 seconds */
2164                 state->closing_wait    = 30000; /* 30 seconds */
2165
2166                 mutex_init(&state->mutex);
2167         }
2168
2169         retval = tty_register_driver(normal);
2170  out:
2171         if (retval < 0) {
2172                 put_tty_driver(normal);
2173                 kfree(drv->state);
2174         }
2175         return retval;
2176 }
2177
2178 /**
2179  *      uart_unregister_driver - remove a driver from the uart core layer
2180  *      @drv: low level driver structure
2181  *
2182  *      Remove all references to a driver from the core driver.  The low
2183  *      level driver must have removed all its ports via the
2184  *      uart_remove_one_port() if it registered them with uart_add_one_port().
2185  *      (ie, drv->port == NULL)
2186  */
2187 void uart_unregister_driver(struct uart_driver *drv)
2188 {
2189         struct tty_driver *p = drv->tty_driver;
2190         tty_unregister_driver(p);
2191         put_tty_driver(p);
2192         kfree(drv->state);
2193         drv->tty_driver = NULL;
2194 }
2195
2196 struct tty_driver *uart_console_device(struct console *co, int *index)
2197 {
2198         struct uart_driver *p = co->data;
2199         *index = co->index;
2200         return p->tty_driver;
2201 }
2202
2203 /**
2204  *      uart_add_one_port - attach a driver-defined port structure
2205  *      @drv: pointer to the uart low level driver structure for this port
2206  *      @port: uart port structure to use for this port.
2207  *
2208  *      This allows the driver to register its own uart_port structure
2209  *      with the core driver.  The main purpose is to allow the low
2210  *      level uart drivers to expand uart_port, rather than having yet
2211  *      more levels of structures.
2212  */
2213 int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
2214 {
2215         struct uart_state *state;
2216         int ret = 0;
2217
2218         BUG_ON(in_interrupt());
2219
2220         if (port->line >= drv->nr)
2221                 return -EINVAL;
2222
2223         state = drv->state + port->line;
2224
2225         mutex_lock(&port_mutex);
2226         if (state->port) {
2227                 ret = -EINVAL;
2228                 goto out;
2229         }
2230
2231         state->port = port;
2232
2233         port->cons = drv->cons;
2234         port->info = state->info;
2235
2236         /*
2237          * If this port is a console, then the spinlock is already
2238          * initialised.
2239          */
2240         if (!(uart_console(port) && (port->cons->flags & CON_ENABLED)))
2241                 spin_lock_init(&port->lock);
2242
2243         uart_configure_port(drv, state, port);
2244
2245         /*
2246          * Register the port whether it's detected or not.  This allows
2247          * setserial to be used to alter this ports parameters.
2248          */
2249         tty_register_device(drv->tty_driver, port->line, port->dev);
2250
2251         /*
2252          * If this driver supports console, and it hasn't been
2253          * successfully registered yet, try to re-register it.
2254          * It may be that the port was not available.
2255          */
2256         if (port->type != PORT_UNKNOWN &&
2257             port->cons && !(port->cons->flags & CON_ENABLED))
2258                 register_console(port->cons);
2259
2260  out:
2261         mutex_unlock(&port_mutex);
2262
2263         return ret;
2264 }
2265
2266 /**
2267  *      uart_remove_one_port - detach a driver defined port structure
2268  *      @drv: pointer to the uart low level driver structure for this port
2269  *      @port: uart port structure for this port
2270  *
2271  *      This unhooks (and hangs up) the specified port structure from the
2272  *      core driver.  No further calls will be made to the low-level code
2273  *      for this port.
2274  */
2275 int uart_remove_one_port(struct uart_driver *drv, struct uart_port *port)
2276 {
2277         struct uart_state *state = drv->state + port->line;
2278
2279         BUG_ON(in_interrupt());
2280
2281         if (state->port != port)
2282                 printk(KERN_ALERT "Removing wrong port: %p != %p\n",
2283                         state->port, port);
2284
2285         mutex_lock(&port_mutex);
2286
2287         /*
2288          * Remove the devices from devfs
2289          */
2290         tty_unregister_device(drv->tty_driver, port->line);
2291
2292         uart_unconfigure_port(drv, state);
2293         state->port = NULL;
2294         mutex_unlock(&port_mutex);
2295
2296         return 0;
2297 }
2298
2299 /*
2300  *      Are the two ports equivalent?
2301  */
2302 int uart_match_port(struct uart_port *port1, struct uart_port *port2)
2303 {
2304         if (port1->iotype != port2->iotype)
2305                 return 0;
2306
2307         switch (port1->iotype) {
2308         case UPIO_PORT:
2309                 return (port1->iobase == port2->iobase);
2310         case UPIO_HUB6:
2311                 return (port1->iobase == port2->iobase) &&
2312                        (port1->hub6   == port2->hub6);
2313         case UPIO_MEM:
2314                 return (port1->mapbase == port2->mapbase);
2315         }
2316         return 0;
2317 }
2318 EXPORT_SYMBOL(uart_match_port);
2319
2320 EXPORT_SYMBOL(uart_write_wakeup);
2321 EXPORT_SYMBOL(uart_register_driver);
2322 EXPORT_SYMBOL(uart_unregister_driver);
2323 EXPORT_SYMBOL(uart_suspend_port);
2324 EXPORT_SYMBOL(uart_resume_port);
2325 EXPORT_SYMBOL(uart_add_one_port);
2326 EXPORT_SYMBOL(uart_remove_one_port);
2327
2328 MODULE_DESCRIPTION("Serial driver core");
2329 MODULE_LICENSE("GPL");