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Linux/drivers/tty/serial/8250/8250_core.c

  1 /*
  2  *  Universal/legacy driver for 8250/16550-type serial ports
  3  *
  4  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
  5  *
  6  *  Copyright (C) 2001 Russell King.
  7  *
  8  *  Supports: ISA-compatible 8250/16550 ports
  9  *            PNP 8250/16550 ports
 10  *            early_serial_setup() ports
 11  *            userspace-configurable "phantom" ports
 12  *            "serial8250" platform devices
 13  *            serial8250_register_8250_port() ports
 14  *
 15  * This program is free software; you can redistribute it and/or modify
 16  * it under the terms of the GNU General Public License as published by
 17  * the Free Software Foundation; either version 2 of the License, or
 18  * (at your option) any later version.
 19  */
 20 
 21 #include <linux/module.h>
 22 #include <linux/moduleparam.h>
 23 #include <linux/ioport.h>
 24 #include <linux/init.h>
 25 #include <linux/console.h>
 26 #include <linux/sysrq.h>
 27 #include <linux/delay.h>
 28 #include <linux/platform_device.h>
 29 #include <linux/tty.h>
 30 #include <linux/ratelimit.h>
 31 #include <linux/tty_flip.h>
 32 #include <linux/serial.h>
 33 #include <linux/serial_8250.h>
 34 #include <linux/nmi.h>
 35 #include <linux/mutex.h>
 36 #include <linux/slab.h>
 37 #include <linux/uaccess.h>
 38 #include <linux/pm_runtime.h>
 39 #include <linux/io.h>
 40 #ifdef CONFIG_SPARC
 41 #include <linux/sunserialcore.h>
 42 #endif
 43 
 44 #include <asm/irq.h>
 45 
 46 #include "8250.h"
 47 
 48 /*
 49  * Configuration:
 50  *   share_irqs - whether we pass IRQF_SHARED to request_irq().  This option
 51  *                is unsafe when used on edge-triggered interrupts.
 52  */
 53 static unsigned int share_irqs = SERIAL8250_SHARE_IRQS;
 54 
 55 static unsigned int nr_uarts = CONFIG_SERIAL_8250_RUNTIME_UARTS;
 56 
 57 static struct uart_driver serial8250_reg;
 58 
 59 static unsigned int skip_txen_test; /* force skip of txen test at init time */
 60 
 61 #define PASS_LIMIT      512
 62 
 63 #include <asm/serial.h>
 64 /*
 65  * SERIAL_PORT_DFNS tells us about built-in ports that have no
 66  * standard enumeration mechanism.   Platforms that can find all
 67  * serial ports via mechanisms like ACPI or PCI need not supply it.
 68  */
 69 #ifndef SERIAL_PORT_DFNS
 70 #define SERIAL_PORT_DFNS
 71 #endif
 72 
 73 static const struct old_serial_port old_serial_port[] = {
 74         SERIAL_PORT_DFNS /* defined in asm/serial.h */
 75 };
 76 
 77 #define UART_NR CONFIG_SERIAL_8250_NR_UARTS
 78 
 79 #ifdef CONFIG_SERIAL_8250_RSA
 80 
 81 #define PORT_RSA_MAX 4
 82 static unsigned long probe_rsa[PORT_RSA_MAX];
 83 static unsigned int probe_rsa_count;
 84 #endif /* CONFIG_SERIAL_8250_RSA  */
 85 
 86 struct irq_info {
 87         struct                  hlist_node node;
 88         int                     irq;
 89         spinlock_t              lock;   /* Protects list not the hash */
 90         struct list_head        *head;
 91 };
 92 
 93 #define NR_IRQ_HASH             32      /* Can be adjusted later */
 94 static struct hlist_head irq_lists[NR_IRQ_HASH];
 95 static DEFINE_MUTEX(hash_mutex);        /* Used to walk the hash */
 96 
 97 /*
 98  * This is the serial driver's interrupt routine.
 99  *
100  * Arjan thinks the old way was overly complex, so it got simplified.
101  * Alan disagrees, saying that need the complexity to handle the weird
102  * nature of ISA shared interrupts.  (This is a special exception.)
103  *
104  * In order to handle ISA shared interrupts properly, we need to check
105  * that all ports have been serviced, and therefore the ISA interrupt
106  * line has been de-asserted.
107  *
108  * This means we need to loop through all ports. checking that they
109  * don't have an interrupt pending.
110  */
111 static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
112 {
113         struct irq_info *i = dev_id;
114         struct list_head *l, *end = NULL;
115         int pass_counter = 0, handled = 0;
116 
117         DEBUG_INTR("serial8250_interrupt(%d)...", irq);
118 
119         spin_lock(&i->lock);
120 
121         l = i->head;
122         do {
123                 struct uart_8250_port *up;
124                 struct uart_port *port;
125 
126                 up = list_entry(l, struct uart_8250_port, list);
127                 port = &up->port;
128 
129                 if (port->handle_irq(port)) {
130                         handled = 1;
131                         end = NULL;
132                 } else if (end == NULL)
133                         end = l;
134 
135                 l = l->next;
136 
137                 if (l == i->head && pass_counter++ > PASS_LIMIT) {
138                         /* If we hit this, we're dead. */
139                         printk_ratelimited(KERN_ERR
140                                 "serial8250: too much work for irq%d\n", irq);
141                         break;
142                 }
143         } while (l != end);
144 
145         spin_unlock(&i->lock);
146 
147         DEBUG_INTR("end.\n");
148 
149         return IRQ_RETVAL(handled);
150 }
151 
152 /*
153  * To support ISA shared interrupts, we need to have one interrupt
154  * handler that ensures that the IRQ line has been deasserted
155  * before returning.  Failing to do this will result in the IRQ
156  * line being stuck active, and, since ISA irqs are edge triggered,
157  * no more IRQs will be seen.
158  */
159 static void serial_do_unlink(struct irq_info *i, struct uart_8250_port *up)
160 {
161         spin_lock_irq(&i->lock);
162 
163         if (!list_empty(i->head)) {
164                 if (i->head == &up->list)
165                         i->head = i->head->next;
166                 list_del(&up->list);
167         } else {
168                 BUG_ON(i->head != &up->list);
169                 i->head = NULL;
170         }
171         spin_unlock_irq(&i->lock);
172         /* List empty so throw away the hash node */
173         if (i->head == NULL) {
174                 hlist_del(&i->node);
175                 kfree(i);
176         }
177 }
178 
179 static int serial_link_irq_chain(struct uart_8250_port *up)
180 {
181         struct hlist_head *h;
182         struct hlist_node *n;
183         struct irq_info *i;
184         int ret, irq_flags = up->port.flags & UPF_SHARE_IRQ ? IRQF_SHARED : 0;
185 
186         mutex_lock(&hash_mutex);
187 
188         h = &irq_lists[up->port.irq % NR_IRQ_HASH];
189 
190         hlist_for_each(n, h) {
191                 i = hlist_entry(n, struct irq_info, node);
192                 if (i->irq == up->port.irq)
193                         break;
194         }
195 
196         if (n == NULL) {
197                 i = kzalloc(sizeof(struct irq_info), GFP_KERNEL);
198                 if (i == NULL) {
199                         mutex_unlock(&hash_mutex);
200                         return -ENOMEM;
201                 }
202                 spin_lock_init(&i->lock);
203                 i->irq = up->port.irq;
204                 hlist_add_head(&i->node, h);
205         }
206         mutex_unlock(&hash_mutex);
207 
208         spin_lock_irq(&i->lock);
209 
210         if (i->head) {
211                 list_add(&up->list, i->head);
212                 spin_unlock_irq(&i->lock);
213 
214                 ret = 0;
215         } else {
216                 INIT_LIST_HEAD(&up->list);
217                 i->head = &up->list;
218                 spin_unlock_irq(&i->lock);
219                 irq_flags |= up->port.irqflags;
220                 ret = request_irq(up->port.irq, serial8250_interrupt,
221                                   irq_flags, "serial", i);
222                 if (ret < 0)
223                         serial_do_unlink(i, up);
224         }
225 
226         return ret;
227 }
228 
229 static void serial_unlink_irq_chain(struct uart_8250_port *up)
230 {
231         /*
232          * yes, some broken gcc emit "warning: 'i' may be used uninitialized"
233          * but no, we are not going to take a patch that assigns NULL below.
234          */
235         struct irq_info *i;
236         struct hlist_node *n;
237         struct hlist_head *h;
238 
239         mutex_lock(&hash_mutex);
240 
241         h = &irq_lists[up->port.irq % NR_IRQ_HASH];
242 
243         hlist_for_each(n, h) {
244                 i = hlist_entry(n, struct irq_info, node);
245                 if (i->irq == up->port.irq)
246                         break;
247         }
248 
249         BUG_ON(n == NULL);
250         BUG_ON(i->head == NULL);
251 
252         if (list_empty(i->head))
253                 free_irq(up->port.irq, i);
254 
255         serial_do_unlink(i, up);
256         mutex_unlock(&hash_mutex);
257 }
258 
259 /*
260  * This function is used to handle ports that do not have an
261  * interrupt.  This doesn't work very well for 16450's, but gives
262  * barely passable results for a 16550A.  (Although at the expense
263  * of much CPU overhead).
264  */
265 static void serial8250_timeout(unsigned long data)
266 {
267         struct uart_8250_port *up = (struct uart_8250_port *)data;
268 
269         up->port.handle_irq(&up->port);
270         mod_timer(&up->timer, jiffies + uart_poll_timeout(&up->port));
271 }
272 
273 static void serial8250_backup_timeout(unsigned long data)
274 {
275         struct uart_8250_port *up = (struct uart_8250_port *)data;
276         unsigned int iir, ier = 0, lsr;
277         unsigned long flags;
278 
279         spin_lock_irqsave(&up->port.lock, flags);
280 
281         /*
282          * Must disable interrupts or else we risk racing with the interrupt
283          * based handler.
284          */
285         if (up->port.irq) {
286                 ier = serial_in(up, UART_IER);
287                 serial_out(up, UART_IER, 0);
288         }
289 
290         iir = serial_in(up, UART_IIR);
291 
292         /*
293          * This should be a safe test for anyone who doesn't trust the
294          * IIR bits on their UART, but it's specifically designed for
295          * the "Diva" UART used on the management processor on many HP
296          * ia64 and parisc boxes.
297          */
298         lsr = serial_in(up, UART_LSR);
299         up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
300         if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
301             (!uart_circ_empty(&up->port.state->xmit) || up->port.x_char) &&
302             (lsr & UART_LSR_THRE)) {
303                 iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
304                 iir |= UART_IIR_THRI;
305         }
306 
307         if (!(iir & UART_IIR_NO_INT))
308                 serial8250_tx_chars(up);
309 
310         if (up->port.irq)
311                 serial_out(up, UART_IER, ier);
312 
313         spin_unlock_irqrestore(&up->port.lock, flags);
314 
315         /* Standard timer interval plus 0.2s to keep the port running */
316         mod_timer(&up->timer,
317                 jiffies + uart_poll_timeout(&up->port) + HZ / 5);
318 }
319 
320 static int univ8250_setup_irq(struct uart_8250_port *up)
321 {
322         struct uart_port *port = &up->port;
323         int retval = 0;
324 
325         /*
326          * The above check will only give an accurate result the first time
327          * the port is opened so this value needs to be preserved.
328          */
329         if (up->bugs & UART_BUG_THRE) {
330                 pr_debug("ttyS%d - using backup timer\n", serial_index(port));
331 
332                 up->timer.function = serial8250_backup_timeout;
333                 up->timer.data = (unsigned long)up;
334                 mod_timer(&up->timer, jiffies +
335                           uart_poll_timeout(port) + HZ / 5);
336         }
337 
338         /*
339          * If the "interrupt" for this port doesn't correspond with any
340          * hardware interrupt, we use a timer-based system.  The original
341          * driver used to do this with IRQ0.
342          */
343         if (!port->irq) {
344                 up->timer.data = (unsigned long)up;
345                 mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
346         } else
347                 retval = serial_link_irq_chain(up);
348 
349         return retval;
350 }
351 
352 static void univ8250_release_irq(struct uart_8250_port *up)
353 {
354         struct uart_port *port = &up->port;
355 
356         del_timer_sync(&up->timer);
357         up->timer.function = serial8250_timeout;
358         if (port->irq)
359                 serial_unlink_irq_chain(up);
360 }
361 
362 #ifdef CONFIG_SERIAL_8250_RSA
363 static int serial8250_request_rsa_resource(struct uart_8250_port *up)
364 {
365         unsigned long start = UART_RSA_BASE << up->port.regshift;
366         unsigned int size = 8 << up->port.regshift;
367         struct uart_port *port = &up->port;
368         int ret = -EINVAL;
369 
370         switch (port->iotype) {
371         case UPIO_HUB6:
372         case UPIO_PORT:
373                 start += port->iobase;
374                 if (request_region(start, size, "serial-rsa"))
375                         ret = 0;
376                 else
377                         ret = -EBUSY;
378                 break;
379         }
380 
381         return ret;
382 }
383 
384 static void serial8250_release_rsa_resource(struct uart_8250_port *up)
385 {
386         unsigned long offset = UART_RSA_BASE << up->port.regshift;
387         unsigned int size = 8 << up->port.regshift;
388         struct uart_port *port = &up->port;
389 
390         switch (port->iotype) {
391         case UPIO_HUB6:
392         case UPIO_PORT:
393                 release_region(port->iobase + offset, size);
394                 break;
395         }
396 }
397 #endif
398 
399 static const struct uart_ops *base_ops;
400 static struct uart_ops univ8250_port_ops;
401 
402 static const struct uart_8250_ops univ8250_driver_ops = {
403         .setup_irq      = univ8250_setup_irq,
404         .release_irq    = univ8250_release_irq,
405 };
406 
407 static struct uart_8250_port serial8250_ports[UART_NR];
408 
409 /**
410  * serial8250_get_port - retrieve struct uart_8250_port
411  * @line: serial line number
412  *
413  * This function retrieves struct uart_8250_port for the specific line.
414  * This struct *must* *not* be used to perform a 8250 or serial core operation
415  * which is not accessible otherwise. Its only purpose is to make the struct
416  * accessible to the runtime-pm callbacks for context suspend/restore.
417  * The lock assumption made here is none because runtime-pm suspend/resume
418  * callbacks should not be invoked if there is any operation performed on the
419  * port.
420  */
421 struct uart_8250_port *serial8250_get_port(int line)
422 {
423         return &serial8250_ports[line];
424 }
425 EXPORT_SYMBOL_GPL(serial8250_get_port);
426 
427 static void (*serial8250_isa_config)(int port, struct uart_port *up,
428         unsigned short *capabilities);
429 
430 void serial8250_set_isa_configurator(
431         void (*v)(int port, struct uart_port *up, unsigned short *capabilities))
432 {
433         serial8250_isa_config = v;
434 }
435 EXPORT_SYMBOL(serial8250_set_isa_configurator);
436 
437 #ifdef CONFIG_SERIAL_8250_RSA
438 
439 static void univ8250_config_port(struct uart_port *port, int flags)
440 {
441         struct uart_8250_port *up = up_to_u8250p(port);
442 
443         up->probe &= ~UART_PROBE_RSA;
444         if (port->type == PORT_RSA) {
445                 if (serial8250_request_rsa_resource(up) == 0)
446                         up->probe |= UART_PROBE_RSA;
447         } else if (flags & UART_CONFIG_TYPE) {
448                 int i;
449 
450                 for (i = 0; i < probe_rsa_count; i++) {
451                         if (probe_rsa[i] == up->port.iobase) {
452                                 if (serial8250_request_rsa_resource(up) == 0)
453                                         up->probe |= UART_PROBE_RSA;
454                                 break;
455                         }
456                 }
457         }
458 
459         base_ops->config_port(port, flags);
460 
461         if (port->type != PORT_RSA && up->probe & UART_PROBE_RSA)
462                 serial8250_release_rsa_resource(up);
463 }
464 
465 static int univ8250_request_port(struct uart_port *port)
466 {
467         struct uart_8250_port *up = up_to_u8250p(port);
468         int ret;
469 
470         ret = base_ops->request_port(port);
471         if (ret == 0 && port->type == PORT_RSA) {
472                 ret = serial8250_request_rsa_resource(up);
473                 if (ret < 0)
474                         base_ops->release_port(port);
475         }
476 
477         return ret;
478 }
479 
480 static void univ8250_release_port(struct uart_port *port)
481 {
482         struct uart_8250_port *up = up_to_u8250p(port);
483 
484         if (port->type == PORT_RSA)
485                 serial8250_release_rsa_resource(up);
486         base_ops->release_port(port);
487 }
488 
489 static void univ8250_rsa_support(struct uart_ops *ops)
490 {
491         ops->config_port  = univ8250_config_port;
492         ops->request_port = univ8250_request_port;
493         ops->release_port = univ8250_release_port;
494 }
495 
496 #else
497 #define univ8250_rsa_support(x)         do { } while (0)
498 #endif /* CONFIG_SERIAL_8250_RSA */
499 
500 static void __init serial8250_isa_init_ports(void)
501 {
502         struct uart_8250_port *up;
503         static int first = 1;
504         int i, irqflag = 0;
505 
506         if (!first)
507                 return;
508         first = 0;
509 
510         if (nr_uarts > UART_NR)
511                 nr_uarts = UART_NR;
512 
513         for (i = 0; i < nr_uarts; i++) {
514                 struct uart_8250_port *up = &serial8250_ports[i];
515                 struct uart_port *port = &up->port;
516 
517                 port->line = i;
518                 serial8250_init_port(up);
519                 if (!base_ops)
520                         base_ops = port->ops;
521                 port->ops = &univ8250_port_ops;
522 
523                 init_timer(&up->timer);
524                 up->timer.function = serial8250_timeout;
525 
526                 up->ops = &univ8250_driver_ops;
527 
528                 /*
529                  * ALPHA_KLUDGE_MCR needs to be killed.
530                  */
531                 up->mcr_mask = ~ALPHA_KLUDGE_MCR;
532                 up->mcr_force = ALPHA_KLUDGE_MCR;
533         }
534 
535         /* chain base port ops to support Remote Supervisor Adapter */
536         univ8250_port_ops = *base_ops;
537         univ8250_rsa_support(&univ8250_port_ops);
538 
539         if (share_irqs)
540                 irqflag = IRQF_SHARED;
541 
542         for (i = 0, up = serial8250_ports;
543              i < ARRAY_SIZE(old_serial_port) && i < nr_uarts;
544              i++, up++) {
545                 struct uart_port *port = &up->port;
546 
547                 port->iobase   = old_serial_port[i].port;
548                 port->irq      = irq_canonicalize(old_serial_port[i].irq);
549                 port->irqflags = old_serial_port[i].irqflags;
550                 port->uartclk  = old_serial_port[i].baud_base * 16;
551                 port->flags    = old_serial_port[i].flags;
552                 port->hub6     = old_serial_port[i].hub6;
553                 port->membase  = old_serial_port[i].iomem_base;
554                 port->iotype   = old_serial_port[i].io_type;
555                 port->regshift = old_serial_port[i].iomem_reg_shift;
556                 serial8250_set_defaults(up);
557 
558                 port->irqflags |= irqflag;
559                 if (serial8250_isa_config != NULL)
560                         serial8250_isa_config(i, &up->port, &up->capabilities);
561         }
562 }
563 
564 static void __init
565 serial8250_register_ports(struct uart_driver *drv, struct device *dev)
566 {
567         int i;
568 
569         for (i = 0; i < nr_uarts; i++) {
570                 struct uart_8250_port *up = &serial8250_ports[i];
571 
572                 if (up->port.type == PORT_8250_CIR)
573                         continue;
574 
575                 if (up->port.dev)
576                         continue;
577 
578                 up->port.dev = dev;
579 
580                 if (skip_txen_test)
581                         up->port.flags |= UPF_NO_TXEN_TEST;
582 
583                 uart_add_one_port(drv, &up->port);
584         }
585 }
586 
587 #ifdef CONFIG_SERIAL_8250_CONSOLE
588 
589 static void univ8250_console_write(struct console *co, const char *s,
590                                    unsigned int count)
591 {
592         struct uart_8250_port *up = &serial8250_ports[co->index];
593 
594         serial8250_console_write(up, s, count);
595 }
596 
597 static int univ8250_console_setup(struct console *co, char *options)
598 {
599         struct uart_port *port;
600 
601         /*
602          * Check whether an invalid uart number has been specified, and
603          * if so, search for the first available port that does have
604          * console support.
605          */
606         if (co->index >= nr_uarts)
607                 co->index = 0;
608         port = &serial8250_ports[co->index].port;
609         /* link port to console */
610         port->cons = co;
611 
612         return serial8250_console_setup(port, options, false);
613 }
614 
615 /**
616  *      univ8250_console_match - non-standard console matching
617  *      @co:      registering console
618  *      @name:    name from console command line
619  *      @idx:     index from console command line
620  *      @options: ptr to option string from console command line
621  *
622  *      Only attempts to match console command lines of the form:
623  *          console=uart[8250],io|mmio|mmio32,<addr>[,<options>]
624  *          console=uart[8250],0x<addr>[,<options>]
625  *      This form is used to register an initial earlycon boot console and
626  *      replace it with the serial8250_console at 8250 driver init.
627  *
628  *      Performs console setup for a match (as required by interface)
629  *      If no <options> are specified, then assume the h/w is already setup.
630  *
631  *      Returns 0 if console matches; otherwise non-zero to use default matching
632  */
633 static int univ8250_console_match(struct console *co, char *name, int idx,
634                                   char *options)
635 {
636         char match[] = "uart";  /* 8250-specific earlycon name */
637         unsigned char iotype;
638         unsigned long addr;
639         int i;
640 
641         if (strncmp(name, match, 4) != 0)
642                 return -ENODEV;
643 
644         if (uart_parse_earlycon(options, &iotype, &addr, &options))
645                 return -ENODEV;
646 
647         /* try to match the port specified on the command line */
648         for (i = 0; i < nr_uarts; i++) {
649                 struct uart_port *port = &serial8250_ports[i].port;
650 
651                 if (port->iotype != iotype)
652                         continue;
653                 if ((iotype == UPIO_MEM || iotype == UPIO_MEM32) &&
654                     (port->mapbase != addr))
655                         continue;
656                 if (iotype == UPIO_PORT && port->iobase != addr)
657                         continue;
658 
659                 co->index = i;
660                 port->cons = co;
661                 return serial8250_console_setup(port, options, true);
662         }
663 
664         return -ENODEV;
665 }
666 
667 static struct console univ8250_console = {
668         .name           = "ttyS",
669         .write          = univ8250_console_write,
670         .device         = uart_console_device,
671         .setup          = univ8250_console_setup,
672         .match          = univ8250_console_match,
673         .flags          = CON_PRINTBUFFER | CON_ANYTIME,
674         .index          = -1,
675         .data           = &serial8250_reg,
676 };
677 
678 static int __init univ8250_console_init(void)
679 {
680         if (nr_uarts == 0)
681                 return -ENODEV;
682 
683         serial8250_isa_init_ports();
684         register_console(&univ8250_console);
685         return 0;
686 }
687 console_initcall(univ8250_console_init);
688 
689 #define SERIAL8250_CONSOLE      &univ8250_console
690 #else
691 #define SERIAL8250_CONSOLE      NULL
692 #endif
693 
694 static struct uart_driver serial8250_reg = {
695         .owner                  = THIS_MODULE,
696         .driver_name            = "serial",
697         .dev_name               = "ttyS",
698         .major                  = TTY_MAJOR,
699         .minor                  = 64,
700         .cons                   = SERIAL8250_CONSOLE,
701 };
702 
703 /*
704  * early_serial_setup - early registration for 8250 ports
705  *
706  * Setup an 8250 port structure prior to console initialisation.  Use
707  * after console initialisation will cause undefined behaviour.
708  */
709 int __init early_serial_setup(struct uart_port *port)
710 {
711         struct uart_port *p;
712 
713         if (port->line >= ARRAY_SIZE(serial8250_ports) || nr_uarts == 0)
714                 return -ENODEV;
715 
716         serial8250_isa_init_ports();
717         p = &serial8250_ports[port->line].port;
718         p->iobase       = port->iobase;
719         p->membase      = port->membase;
720         p->irq          = port->irq;
721         p->irqflags     = port->irqflags;
722         p->uartclk      = port->uartclk;
723         p->fifosize     = port->fifosize;
724         p->regshift     = port->regshift;
725         p->iotype       = port->iotype;
726         p->flags        = port->flags;
727         p->mapbase      = port->mapbase;
728         p->mapsize      = port->mapsize;
729         p->private_data = port->private_data;
730         p->type         = port->type;
731         p->line         = port->line;
732 
733         serial8250_set_defaults(up_to_u8250p(p));
734 
735         if (port->serial_in)
736                 p->serial_in = port->serial_in;
737         if (port->serial_out)
738                 p->serial_out = port->serial_out;
739         if (port->handle_irq)
740                 p->handle_irq = port->handle_irq;
741 
742         return 0;
743 }
744 
745 /**
746  *      serial8250_suspend_port - suspend one serial port
747  *      @line:  serial line number
748  *
749  *      Suspend one serial port.
750  */
751 void serial8250_suspend_port(int line)
752 {
753         struct uart_8250_port *up = &serial8250_ports[line];
754         struct uart_port *port = &up->port;
755 
756         if (!console_suspend_enabled && uart_console(port) &&
757             port->type != PORT_8250) {
758                 unsigned char canary = 0xa5;
759                 serial_out(up, UART_SCR, canary);
760                 if (serial_in(up, UART_SCR) == canary)
761                         up->canary = canary;
762         }
763 
764         uart_suspend_port(&serial8250_reg, port);
765 }
766 
767 /**
768  *      serial8250_resume_port - resume one serial port
769  *      @line:  serial line number
770  *
771  *      Resume one serial port.
772  */
773 void serial8250_resume_port(int line)
774 {
775         struct uart_8250_port *up = &serial8250_ports[line];
776         struct uart_port *port = &up->port;
777 
778         up->canary = 0;
779 
780         if (up->capabilities & UART_NATSEMI) {
781                 /* Ensure it's still in high speed mode */
782                 serial_port_out(port, UART_LCR, 0xE0);
783 
784                 ns16550a_goto_highspeed(up);
785 
786                 serial_port_out(port, UART_LCR, 0);
787                 port->uartclk = 921600*16;
788         }
789         uart_resume_port(&serial8250_reg, port);
790 }
791 
792 /*
793  * Register a set of serial devices attached to a platform device.  The
794  * list is terminated with a zero flags entry, which means we expect
795  * all entries to have at least UPF_BOOT_AUTOCONF set.
796  */
797 static int serial8250_probe(struct platform_device *dev)
798 {
799         struct plat_serial8250_port *p = dev_get_platdata(&dev->dev);
800         struct uart_8250_port uart;
801         int ret, i, irqflag = 0;
802 
803         memset(&uart, 0, sizeof(uart));
804 
805         if (share_irqs)
806                 irqflag = IRQF_SHARED;
807 
808         for (i = 0; p && p->flags != 0; p++, i++) {
809                 uart.port.iobase        = p->iobase;
810                 uart.port.membase       = p->membase;
811                 uart.port.irq           = p->irq;
812                 uart.port.irqflags      = p->irqflags;
813                 uart.port.uartclk       = p->uartclk;
814                 uart.port.regshift      = p->regshift;
815                 uart.port.iotype        = p->iotype;
816                 uart.port.flags         = p->flags;
817                 uart.port.mapbase       = p->mapbase;
818                 uart.port.hub6          = p->hub6;
819                 uart.port.private_data  = p->private_data;
820                 uart.port.type          = p->type;
821                 uart.port.serial_in     = p->serial_in;
822                 uart.port.serial_out    = p->serial_out;
823                 uart.port.handle_irq    = p->handle_irq;
824                 uart.port.handle_break  = p->handle_break;
825                 uart.port.set_termios   = p->set_termios;
826                 uart.port.pm            = p->pm;
827                 uart.port.dev           = &dev->dev;
828                 uart.port.irqflags      |= irqflag;
829                 ret = serial8250_register_8250_port(&uart);
830                 if (ret < 0) {
831                         dev_err(&dev->dev, "unable to register port at index %d "
832                                 "(IO%lx MEM%llx IRQ%d): %d\n", i,
833                                 p->iobase, (unsigned long long)p->mapbase,
834                                 p->irq, ret);
835                 }
836         }
837         return 0;
838 }
839 
840 /*
841  * Remove serial ports registered against a platform device.
842  */
843 static int serial8250_remove(struct platform_device *dev)
844 {
845         int i;
846 
847         for (i = 0; i < nr_uarts; i++) {
848                 struct uart_8250_port *up = &serial8250_ports[i];
849 
850                 if (up->port.dev == &dev->dev)
851                         serial8250_unregister_port(i);
852         }
853         return 0;
854 }
855 
856 static int serial8250_suspend(struct platform_device *dev, pm_message_t state)
857 {
858         int i;
859 
860         for (i = 0; i < UART_NR; i++) {
861                 struct uart_8250_port *up = &serial8250_ports[i];
862 
863                 if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
864                         uart_suspend_port(&serial8250_reg, &up->port);
865         }
866 
867         return 0;
868 }
869 
870 static int serial8250_resume(struct platform_device *dev)
871 {
872         int i;
873 
874         for (i = 0; i < UART_NR; i++) {
875                 struct uart_8250_port *up = &serial8250_ports[i];
876 
877                 if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
878                         serial8250_resume_port(i);
879         }
880 
881         return 0;
882 }
883 
884 static struct platform_driver serial8250_isa_driver = {
885         .probe          = serial8250_probe,
886         .remove         = serial8250_remove,
887         .suspend        = serial8250_suspend,
888         .resume         = serial8250_resume,
889         .driver         = {
890                 .name   = "serial8250",
891         },
892 };
893 
894 /*
895  * This "device" covers _all_ ISA 8250-compatible serial devices listed
896  * in the table in include/asm/serial.h
897  */
898 static struct platform_device *serial8250_isa_devs;
899 
900 /*
901  * serial8250_register_8250_port and serial8250_unregister_port allows for
902  * 16x50 serial ports to be configured at run-time, to support PCMCIA
903  * modems and PCI multiport cards.
904  */
905 static DEFINE_MUTEX(serial_mutex);
906 
907 static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port *port)
908 {
909         int i;
910 
911         /*
912          * First, find a port entry which matches.
913          */
914         for (i = 0; i < nr_uarts; i++)
915                 if (uart_match_port(&serial8250_ports[i].port, port))
916                         return &serial8250_ports[i];
917 
918         /* try line number first if still available */
919         i = port->line;
920         if (i < nr_uarts && serial8250_ports[i].port.type == PORT_UNKNOWN &&
921                         serial8250_ports[i].port.iobase == 0)
922                 return &serial8250_ports[i];
923         /*
924          * We didn't find a matching entry, so look for the first
925          * free entry.  We look for one which hasn't been previously
926          * used (indicated by zero iobase).
927          */
928         for (i = 0; i < nr_uarts; i++)
929                 if (serial8250_ports[i].port.type == PORT_UNKNOWN &&
930                     serial8250_ports[i].port.iobase == 0)
931                         return &serial8250_ports[i];
932 
933         /*
934          * That also failed.  Last resort is to find any entry which
935          * doesn't have a real port associated with it.
936          */
937         for (i = 0; i < nr_uarts; i++)
938                 if (serial8250_ports[i].port.type == PORT_UNKNOWN)
939                         return &serial8250_ports[i];
940 
941         return NULL;
942 }
943 
944 /**
945  *      serial8250_register_8250_port - register a serial port
946  *      @up: serial port template
947  *
948  *      Configure the serial port specified by the request. If the
949  *      port exists and is in use, it is hung up and unregistered
950  *      first.
951  *
952  *      The port is then probed and if necessary the IRQ is autodetected
953  *      If this fails an error is returned.
954  *
955  *      On success the port is ready to use and the line number is returned.
956  */
957 int serial8250_register_8250_port(struct uart_8250_port *up)
958 {
959         struct uart_8250_port *uart;
960         int ret = -ENOSPC;
961 
962         if (up->port.uartclk == 0)
963                 return -EINVAL;
964 
965         mutex_lock(&serial_mutex);
966 
967         uart = serial8250_find_match_or_unused(&up->port);
968         if (uart && uart->port.type != PORT_8250_CIR) {
969                 if (uart->port.dev)
970                         uart_remove_one_port(&serial8250_reg, &uart->port);
971 
972                 uart->port.iobase       = up->port.iobase;
973                 uart->port.membase      = up->port.membase;
974                 uart->port.irq          = up->port.irq;
975                 uart->port.irqflags     = up->port.irqflags;
976                 uart->port.uartclk      = up->port.uartclk;
977                 uart->port.fifosize     = up->port.fifosize;
978                 uart->port.regshift     = up->port.regshift;
979                 uart->port.iotype       = up->port.iotype;
980                 uart->port.flags        = up->port.flags | UPF_BOOT_AUTOCONF;
981                 uart->bugs              = up->bugs;
982                 uart->port.mapbase      = up->port.mapbase;
983                 uart->port.mapsize      = up->port.mapsize;
984                 uart->port.private_data = up->port.private_data;
985                 uart->tx_loadsz         = up->tx_loadsz;
986                 uart->capabilities      = up->capabilities;
987                 uart->port.throttle     = up->port.throttle;
988                 uart->port.unthrottle   = up->port.unthrottle;
989                 uart->port.rs485_config = up->port.rs485_config;
990                 uart->port.rs485        = up->port.rs485;
991                 uart->dma               = up->dma;
992 
993                 /* Take tx_loadsz from fifosize if it wasn't set separately */
994                 if (uart->port.fifosize && !uart->tx_loadsz)
995                         uart->tx_loadsz = uart->port.fifosize;
996 
997                 if (up->port.dev)
998                         uart->port.dev = up->port.dev;
999 
1000                 if (skip_txen_test)
1001                         uart->port.flags |= UPF_NO_TXEN_TEST;
1002 
1003                 if (up->port.flags & UPF_FIXED_TYPE)
1004                         uart->port.type = up->port.type;
1005 
1006                 serial8250_set_defaults(uart);
1007 
1008                 /* Possibly override default I/O functions.  */
1009                 if (up->port.serial_in)
1010                         uart->port.serial_in = up->port.serial_in;
1011                 if (up->port.serial_out)
1012                         uart->port.serial_out = up->port.serial_out;
1013                 if (up->port.handle_irq)
1014                         uart->port.handle_irq = up->port.handle_irq;
1015                 /*  Possibly override set_termios call */
1016                 if (up->port.set_termios)
1017                         uart->port.set_termios = up->port.set_termios;
1018                 if (up->port.set_mctrl)
1019                         uart->port.set_mctrl = up->port.set_mctrl;
1020                 if (up->port.startup)
1021                         uart->port.startup = up->port.startup;
1022                 if (up->port.shutdown)
1023                         uart->port.shutdown = up->port.shutdown;
1024                 if (up->port.pm)
1025                         uart->port.pm = up->port.pm;
1026                 if (up->port.handle_break)
1027                         uart->port.handle_break = up->port.handle_break;
1028                 if (up->dl_read)
1029                         uart->dl_read = up->dl_read;
1030                 if (up->dl_write)
1031                         uart->dl_write = up->dl_write;
1032 
1033                 if (uart->port.type != PORT_8250_CIR) {
1034                         if (serial8250_isa_config != NULL)
1035                                 serial8250_isa_config(0, &uart->port,
1036                                                 &uart->capabilities);
1037 
1038                         ret = uart_add_one_port(&serial8250_reg,
1039                                                 &uart->port);
1040                         if (ret == 0)
1041                                 ret = uart->port.line;
1042                 } else {
1043                         dev_info(uart->port.dev,
1044                                 "skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
1045                                 uart->port.iobase,
1046                                 (unsigned long long)uart->port.mapbase,
1047                                 uart->port.irq);
1048 
1049                         ret = 0;
1050                 }
1051         }
1052         mutex_unlock(&serial_mutex);
1053 
1054         return ret;
1055 }
1056 EXPORT_SYMBOL(serial8250_register_8250_port);
1057 
1058 /**
1059  *      serial8250_unregister_port - remove a 16x50 serial port at runtime
1060  *      @line: serial line number
1061  *
1062  *      Remove one serial port.  This may not be called from interrupt
1063  *      context.  We hand the port back to the our control.
1064  */
1065 void serial8250_unregister_port(int line)
1066 {
1067         struct uart_8250_port *uart = &serial8250_ports[line];
1068 
1069         mutex_lock(&serial_mutex);
1070         uart_remove_one_port(&serial8250_reg, &uart->port);
1071         if (serial8250_isa_devs) {
1072                 uart->port.flags &= ~UPF_BOOT_AUTOCONF;
1073                 if (skip_txen_test)
1074                         uart->port.flags |= UPF_NO_TXEN_TEST;
1075                 uart->port.type = PORT_UNKNOWN;
1076                 uart->port.dev = &serial8250_isa_devs->dev;
1077                 uart->capabilities = 0;
1078                 uart_add_one_port(&serial8250_reg, &uart->port);
1079         } else {
1080                 uart->port.dev = NULL;
1081         }
1082         mutex_unlock(&serial_mutex);
1083 }
1084 EXPORT_SYMBOL(serial8250_unregister_port);
1085 
1086 static int __init serial8250_init(void)
1087 {
1088         int ret;
1089 
1090         if (nr_uarts == 0)
1091                 return -ENODEV;
1092 
1093         serial8250_isa_init_ports();
1094 
1095         printk(KERN_INFO "Serial: 8250/16550 driver, "
1096                 "%d ports, IRQ sharing %sabled\n", nr_uarts,
1097                 share_irqs ? "en" : "dis");
1098 
1099 #ifdef CONFIG_SPARC
1100         ret = sunserial_register_minors(&serial8250_reg, UART_NR);
1101 #else
1102         serial8250_reg.nr = UART_NR;
1103         ret = uart_register_driver(&serial8250_reg);
1104 #endif
1105         if (ret)
1106                 goto out;
1107 
1108         ret = serial8250_pnp_init();
1109         if (ret)
1110                 goto unreg_uart_drv;
1111 
1112         serial8250_isa_devs = platform_device_alloc("serial8250",
1113                                                     PLAT8250_DEV_LEGACY);
1114         if (!serial8250_isa_devs) {
1115                 ret = -ENOMEM;
1116                 goto unreg_pnp;
1117         }
1118 
1119         ret = platform_device_add(serial8250_isa_devs);
1120         if (ret)
1121                 goto put_dev;
1122 
1123         serial8250_register_ports(&serial8250_reg, &serial8250_isa_devs->dev);
1124 
1125         ret = platform_driver_register(&serial8250_isa_driver);
1126         if (ret == 0)
1127                 goto out;
1128 
1129         platform_device_del(serial8250_isa_devs);
1130 put_dev:
1131         platform_device_put(serial8250_isa_devs);
1132 unreg_pnp:
1133         serial8250_pnp_exit();
1134 unreg_uart_drv:
1135 #ifdef CONFIG_SPARC
1136         sunserial_unregister_minors(&serial8250_reg, UART_NR);
1137 #else
1138         uart_unregister_driver(&serial8250_reg);
1139 #endif
1140 out:
1141         return ret;
1142 }
1143 
1144 static void __exit serial8250_exit(void)
1145 {
1146         struct platform_device *isa_dev = serial8250_isa_devs;
1147 
1148         /*
1149          * This tells serial8250_unregister_port() not to re-register
1150          * the ports (thereby making serial8250_isa_driver permanently
1151          * in use.)
1152          */
1153         serial8250_isa_devs = NULL;
1154 
1155         platform_driver_unregister(&serial8250_isa_driver);
1156         platform_device_unregister(isa_dev);
1157 
1158         serial8250_pnp_exit();
1159 
1160 #ifdef CONFIG_SPARC
1161         sunserial_unregister_minors(&serial8250_reg, UART_NR);
1162 #else
1163         uart_unregister_driver(&serial8250_reg);
1164 #endif
1165 }
1166 
1167 module_init(serial8250_init);
1168 module_exit(serial8250_exit);
1169 
1170 EXPORT_SYMBOL(serial8250_suspend_port);
1171 EXPORT_SYMBOL(serial8250_resume_port);
1172 
1173 MODULE_LICENSE("GPL");
1174 MODULE_DESCRIPTION("Generic 8250/16x50 serial driver");
1175 
1176 module_param(share_irqs, uint, 0644);
1177 MODULE_PARM_DESC(share_irqs, "Share IRQs with other non-8250/16x50 devices"
1178         " (unsafe)");
1179 
1180 module_param(nr_uarts, uint, 0644);
1181 MODULE_PARM_DESC(nr_uarts, "Maximum number of UARTs supported. (1-" __MODULE_STRING(CONFIG_SERIAL_8250_NR_UARTS) ")");
1182 
1183 module_param(skip_txen_test, uint, 0644);
1184 MODULE_PARM_DESC(skip_txen_test, "Skip checking for the TXEN bug at init time");
1185 
1186 #ifdef CONFIG_SERIAL_8250_RSA
1187 module_param_array(probe_rsa, ulong, &probe_rsa_count, 0444);
1188 MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");
1189 #endif
1190 MODULE_ALIAS_CHARDEV_MAJOR(TTY_MAJOR);
1191 
1192 #ifdef CONFIG_SERIAL_8250_DEPRECATED_OPTIONS
1193 #ifndef MODULE
1194 /* This module was renamed to 8250_core in 3.7.  Keep the old "8250" name
1195  * working as well for the module options so we don't break people.  We
1196  * need to keep the names identical and the convenient macros will happily
1197  * refuse to let us do that by failing the build with redefinition errors
1198  * of global variables.  So we stick them inside a dummy function to avoid
1199  * those conflicts.  The options still get parsed, and the redefined
1200  * MODULE_PARAM_PREFIX lets us keep the "8250." syntax alive.
1201  *
1202  * This is hacky.  I'm sorry.
1203  */
1204 static void __used s8250_options(void)
1205 {
1206 #undef MODULE_PARAM_PREFIX
1207 #define MODULE_PARAM_PREFIX "8250_core."
1208 
1209         module_param_cb(share_irqs, &param_ops_uint, &share_irqs, 0644);
1210         module_param_cb(nr_uarts, &param_ops_uint, &nr_uarts, 0644);
1211         module_param_cb(skip_txen_test, &param_ops_uint, &skip_txen_test, 0644);
1212 #ifdef CONFIG_SERIAL_8250_RSA
1213         __module_param_call(MODULE_PARAM_PREFIX, probe_rsa,
1214                 &param_array_ops, .arr = &__param_arr_probe_rsa,
1215                 0444, -1, 0);
1216 #endif
1217 }
1218 #else
1219 MODULE_ALIAS("8250_core");
1220 #endif
1221 #endif
1222 

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