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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|mmio16|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_MEM16 ||
654                      iotype == UPIO_MEM32 || iotype == UPIO_MEM32BE)
655                     && (port->mapbase != addr))
656                         continue;
657                 if (iotype == UPIO_PORT && port->iobase != addr)
658                         continue;
659 
660                 co->index = i;
661                 port->cons = co;
662                 return serial8250_console_setup(port, options, true);
663         }
664 
665         return -ENODEV;
666 }
667 
668 static struct console univ8250_console = {
669         .name           = "ttyS",
670         .write          = univ8250_console_write,
671         .device         = uart_console_device,
672         .setup          = univ8250_console_setup,
673         .match          = univ8250_console_match,
674         .flags          = CON_PRINTBUFFER | CON_ANYTIME,
675         .index          = -1,
676         .data           = &serial8250_reg,
677 };
678 
679 static int __init univ8250_console_init(void)
680 {
681         if (nr_uarts == 0)
682                 return -ENODEV;
683 
684         serial8250_isa_init_ports();
685         register_console(&univ8250_console);
686         return 0;
687 }
688 console_initcall(univ8250_console_init);
689 
690 #define SERIAL8250_CONSOLE      &univ8250_console
691 #else
692 #define SERIAL8250_CONSOLE      NULL
693 #endif
694 
695 static struct uart_driver serial8250_reg = {
696         .owner                  = THIS_MODULE,
697         .driver_name            = "serial",
698         .dev_name               = "ttyS",
699         .major                  = TTY_MAJOR,
700         .minor                  = 64,
701         .cons                   = SERIAL8250_CONSOLE,
702 };
703 
704 /*
705  * early_serial_setup - early registration for 8250 ports
706  *
707  * Setup an 8250 port structure prior to console initialisation.  Use
708  * after console initialisation will cause undefined behaviour.
709  */
710 int __init early_serial_setup(struct uart_port *port)
711 {
712         struct uart_port *p;
713 
714         if (port->line >= ARRAY_SIZE(serial8250_ports) || nr_uarts == 0)
715                 return -ENODEV;
716 
717         serial8250_isa_init_ports();
718         p = &serial8250_ports[port->line].port;
719         p->iobase       = port->iobase;
720         p->membase      = port->membase;
721         p->irq          = port->irq;
722         p->irqflags     = port->irqflags;
723         p->uartclk      = port->uartclk;
724         p->fifosize     = port->fifosize;
725         p->regshift     = port->regshift;
726         p->iotype       = port->iotype;
727         p->flags        = port->flags;
728         p->mapbase      = port->mapbase;
729         p->mapsize      = port->mapsize;
730         p->private_data = port->private_data;
731         p->type         = port->type;
732         p->line         = port->line;
733 
734         serial8250_set_defaults(up_to_u8250p(p));
735 
736         if (port->serial_in)
737                 p->serial_in = port->serial_in;
738         if (port->serial_out)
739                 p->serial_out = port->serial_out;
740         if (port->handle_irq)
741                 p->handle_irq = port->handle_irq;
742 
743         return 0;
744 }
745 
746 /**
747  *      serial8250_suspend_port - suspend one serial port
748  *      @line:  serial line number
749  *
750  *      Suspend one serial port.
751  */
752 void serial8250_suspend_port(int line)
753 {
754         struct uart_8250_port *up = &serial8250_ports[line];
755         struct uart_port *port = &up->port;
756 
757         if (!console_suspend_enabled && uart_console(port) &&
758             port->type != PORT_8250) {
759                 unsigned char canary = 0xa5;
760                 serial_out(up, UART_SCR, canary);
761                 if (serial_in(up, UART_SCR) == canary)
762                         up->canary = canary;
763         }
764 
765         uart_suspend_port(&serial8250_reg, port);
766 }
767 
768 /**
769  *      serial8250_resume_port - resume one serial port
770  *      @line:  serial line number
771  *
772  *      Resume one serial port.
773  */
774 void serial8250_resume_port(int line)
775 {
776         struct uart_8250_port *up = &serial8250_ports[line];
777         struct uart_port *port = &up->port;
778 
779         up->canary = 0;
780 
781         if (up->capabilities & UART_NATSEMI) {
782                 /* Ensure it's still in high speed mode */
783                 serial_port_out(port, UART_LCR, 0xE0);
784 
785                 ns16550a_goto_highspeed(up);
786 
787                 serial_port_out(port, UART_LCR, 0);
788                 port->uartclk = 921600*16;
789         }
790         uart_resume_port(&serial8250_reg, port);
791 }
792 
793 /*
794  * Register a set of serial devices attached to a platform device.  The
795  * list is terminated with a zero flags entry, which means we expect
796  * all entries to have at least UPF_BOOT_AUTOCONF set.
797  */
798 static int serial8250_probe(struct platform_device *dev)
799 {
800         struct plat_serial8250_port *p = dev_get_platdata(&dev->dev);
801         struct uart_8250_port uart;
802         int ret, i, irqflag = 0;
803 
804         memset(&uart, 0, sizeof(uart));
805 
806         if (share_irqs)
807                 irqflag = IRQF_SHARED;
808 
809         for (i = 0; p && p->flags != 0; p++, i++) {
810                 uart.port.iobase        = p->iobase;
811                 uart.port.membase       = p->membase;
812                 uart.port.irq           = p->irq;
813                 uart.port.irqflags      = p->irqflags;
814                 uart.port.uartclk       = p->uartclk;
815                 uart.port.regshift      = p->regshift;
816                 uart.port.iotype        = p->iotype;
817                 uart.port.flags         = p->flags;
818                 uart.port.mapbase       = p->mapbase;
819                 uart.port.hub6          = p->hub6;
820                 uart.port.private_data  = p->private_data;
821                 uart.port.type          = p->type;
822                 uart.port.serial_in     = p->serial_in;
823                 uart.port.serial_out    = p->serial_out;
824                 uart.port.handle_irq    = p->handle_irq;
825                 uart.port.handle_break  = p->handle_break;
826                 uart.port.set_termios   = p->set_termios;
827                 uart.port.pm            = p->pm;
828                 uart.port.dev           = &dev->dev;
829                 uart.port.irqflags      |= irqflag;
830                 ret = serial8250_register_8250_port(&uart);
831                 if (ret < 0) {
832                         dev_err(&dev->dev, "unable to register port at index %d "
833                                 "(IO%lx MEM%llx IRQ%d): %d\n", i,
834                                 p->iobase, (unsigned long long)p->mapbase,
835                                 p->irq, ret);
836                 }
837         }
838         return 0;
839 }
840 
841 /*
842  * Remove serial ports registered against a platform device.
843  */
844 static int serial8250_remove(struct platform_device *dev)
845 {
846         int i;
847 
848         for (i = 0; i < nr_uarts; i++) {
849                 struct uart_8250_port *up = &serial8250_ports[i];
850 
851                 if (up->port.dev == &dev->dev)
852                         serial8250_unregister_port(i);
853         }
854         return 0;
855 }
856 
857 static int serial8250_suspend(struct platform_device *dev, pm_message_t state)
858 {
859         int i;
860 
861         for (i = 0; i < UART_NR; i++) {
862                 struct uart_8250_port *up = &serial8250_ports[i];
863 
864                 if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
865                         uart_suspend_port(&serial8250_reg, &up->port);
866         }
867 
868         return 0;
869 }
870 
871 static int serial8250_resume(struct platform_device *dev)
872 {
873         int i;
874 
875         for (i = 0; i < UART_NR; i++) {
876                 struct uart_8250_port *up = &serial8250_ports[i];
877 
878                 if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
879                         serial8250_resume_port(i);
880         }
881 
882         return 0;
883 }
884 
885 static struct platform_driver serial8250_isa_driver = {
886         .probe          = serial8250_probe,
887         .remove         = serial8250_remove,
888         .suspend        = serial8250_suspend,
889         .resume         = serial8250_resume,
890         .driver         = {
891                 .name   = "serial8250",
892         },
893 };
894 
895 /*
896  * This "device" covers _all_ ISA 8250-compatible serial devices listed
897  * in the table in include/asm/serial.h
898  */
899 static struct platform_device *serial8250_isa_devs;
900 
901 /*
902  * serial8250_register_8250_port and serial8250_unregister_port allows for
903  * 16x50 serial ports to be configured at run-time, to support PCMCIA
904  * modems and PCI multiport cards.
905  */
906 static DEFINE_MUTEX(serial_mutex);
907 
908 static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port *port)
909 {
910         int i;
911 
912         /*
913          * First, find a port entry which matches.
914          */
915         for (i = 0; i < nr_uarts; i++)
916                 if (uart_match_port(&serial8250_ports[i].port, port))
917                         return &serial8250_ports[i];
918 
919         /* try line number first if still available */
920         i = port->line;
921         if (i < nr_uarts && serial8250_ports[i].port.type == PORT_UNKNOWN &&
922                         serial8250_ports[i].port.iobase == 0)
923                 return &serial8250_ports[i];
924         /*
925          * We didn't find a matching entry, so look for the first
926          * free entry.  We look for one which hasn't been previously
927          * used (indicated by zero iobase).
928          */
929         for (i = 0; i < nr_uarts; i++)
930                 if (serial8250_ports[i].port.type == PORT_UNKNOWN &&
931                     serial8250_ports[i].port.iobase == 0)
932                         return &serial8250_ports[i];
933 
934         /*
935          * That also failed.  Last resort is to find any entry which
936          * doesn't have a real port associated with it.
937          */
938         for (i = 0; i < nr_uarts; i++)
939                 if (serial8250_ports[i].port.type == PORT_UNKNOWN)
940                         return &serial8250_ports[i];
941 
942         return NULL;
943 }
944 
945 /**
946  *      serial8250_register_8250_port - register a serial port
947  *      @up: serial port template
948  *
949  *      Configure the serial port specified by the request. If the
950  *      port exists and is in use, it is hung up and unregistered
951  *      first.
952  *
953  *      The port is then probed and if necessary the IRQ is autodetected
954  *      If this fails an error is returned.
955  *
956  *      On success the port is ready to use and the line number is returned.
957  */
958 int serial8250_register_8250_port(struct uart_8250_port *up)
959 {
960         struct uart_8250_port *uart;
961         int ret = -ENOSPC;
962 
963         if (up->port.uartclk == 0)
964                 return -EINVAL;
965 
966         mutex_lock(&serial_mutex);
967 
968         uart = serial8250_find_match_or_unused(&up->port);
969         if (uart && uart->port.type != PORT_8250_CIR) {
970                 if (uart->port.dev)
971                         uart_remove_one_port(&serial8250_reg, &uart->port);
972 
973                 uart->port.iobase       = up->port.iobase;
974                 uart->port.membase      = up->port.membase;
975                 uart->port.irq          = up->port.irq;
976                 uart->port.irqflags     = up->port.irqflags;
977                 uart->port.uartclk      = up->port.uartclk;
978                 uart->port.fifosize     = up->port.fifosize;
979                 uart->port.regshift     = up->port.regshift;
980                 uart->port.iotype       = up->port.iotype;
981                 uart->port.flags        = up->port.flags | UPF_BOOT_AUTOCONF;
982                 uart->bugs              = up->bugs;
983                 uart->port.mapbase      = up->port.mapbase;
984                 uart->port.mapsize      = up->port.mapsize;
985                 uart->port.private_data = up->port.private_data;
986                 uart->tx_loadsz         = up->tx_loadsz;
987                 uart->capabilities      = up->capabilities;
988                 uart->port.throttle     = up->port.throttle;
989                 uart->port.unthrottle   = up->port.unthrottle;
990                 uart->port.rs485_config = up->port.rs485_config;
991                 uart->port.rs485        = up->port.rs485;
992                 uart->dma               = up->dma;
993 
994                 /* Take tx_loadsz from fifosize if it wasn't set separately */
995                 if (uart->port.fifosize && !uart->tx_loadsz)
996                         uart->tx_loadsz = uart->port.fifosize;
997 
998                 if (up->port.dev)
999                         uart->port.dev = up->port.dev;
1000 
1001                 if (skip_txen_test)
1002                         uart->port.flags |= UPF_NO_TXEN_TEST;
1003 
1004                 if (up->port.flags & UPF_FIXED_TYPE)
1005                         uart->port.type = up->port.type;
1006 
1007                 serial8250_set_defaults(uart);
1008 
1009                 /* Possibly override default I/O functions.  */
1010                 if (up->port.serial_in)
1011                         uart->port.serial_in = up->port.serial_in;
1012                 if (up->port.serial_out)
1013                         uart->port.serial_out = up->port.serial_out;
1014                 if (up->port.handle_irq)
1015                         uart->port.handle_irq = up->port.handle_irq;
1016                 /*  Possibly override set_termios call */
1017                 if (up->port.set_termios)
1018                         uart->port.set_termios = up->port.set_termios;
1019                 if (up->port.set_mctrl)
1020                         uart->port.set_mctrl = up->port.set_mctrl;
1021                 if (up->port.startup)
1022                         uart->port.startup = up->port.startup;
1023                 if (up->port.shutdown)
1024                         uart->port.shutdown = up->port.shutdown;
1025                 if (up->port.pm)
1026                         uart->port.pm = up->port.pm;
1027                 if (up->port.handle_break)
1028                         uart->port.handle_break = up->port.handle_break;
1029                 if (up->dl_read)
1030                         uart->dl_read = up->dl_read;
1031                 if (up->dl_write)
1032                         uart->dl_write = up->dl_write;
1033 
1034                 if (uart->port.type != PORT_8250_CIR) {
1035                         if (serial8250_isa_config != NULL)
1036                                 serial8250_isa_config(0, &uart->port,
1037                                                 &uart->capabilities);
1038 
1039                         ret = uart_add_one_port(&serial8250_reg,
1040                                                 &uart->port);
1041                         if (ret == 0)
1042                                 ret = uart->port.line;
1043                 } else {
1044                         dev_info(uart->port.dev,
1045                                 "skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
1046                                 uart->port.iobase,
1047                                 (unsigned long long)uart->port.mapbase,
1048                                 uart->port.irq);
1049 
1050                         ret = 0;
1051                 }
1052         }
1053         mutex_unlock(&serial_mutex);
1054 
1055         return ret;
1056 }
1057 EXPORT_SYMBOL(serial8250_register_8250_port);
1058 
1059 /**
1060  *      serial8250_unregister_port - remove a 16x50 serial port at runtime
1061  *      @line: serial line number
1062  *
1063  *      Remove one serial port.  This may not be called from interrupt
1064  *      context.  We hand the port back to the our control.
1065  */
1066 void serial8250_unregister_port(int line)
1067 {
1068         struct uart_8250_port *uart = &serial8250_ports[line];
1069 
1070         mutex_lock(&serial_mutex);
1071         uart_remove_one_port(&serial8250_reg, &uart->port);
1072         if (serial8250_isa_devs) {
1073                 uart->port.flags &= ~UPF_BOOT_AUTOCONF;
1074                 if (skip_txen_test)
1075                         uart->port.flags |= UPF_NO_TXEN_TEST;
1076                 uart->port.type = PORT_UNKNOWN;
1077                 uart->port.dev = &serial8250_isa_devs->dev;
1078                 uart->capabilities = 0;
1079                 uart_add_one_port(&serial8250_reg, &uart->port);
1080         } else {
1081                 uart->port.dev = NULL;
1082         }
1083         mutex_unlock(&serial_mutex);
1084 }
1085 EXPORT_SYMBOL(serial8250_unregister_port);
1086 
1087 static int __init serial8250_init(void)
1088 {
1089         int ret;
1090 
1091         if (nr_uarts == 0)
1092                 return -ENODEV;
1093 
1094         serial8250_isa_init_ports();
1095 
1096         printk(KERN_INFO "Serial: 8250/16550 driver, "
1097                 "%d ports, IRQ sharing %sabled\n", nr_uarts,
1098                 share_irqs ? "en" : "dis");
1099 
1100 #ifdef CONFIG_SPARC
1101         ret = sunserial_register_minors(&serial8250_reg, UART_NR);
1102 #else
1103         serial8250_reg.nr = UART_NR;
1104         ret = uart_register_driver(&serial8250_reg);
1105 #endif
1106         if (ret)
1107                 goto out;
1108 
1109         ret = serial8250_pnp_init();
1110         if (ret)
1111                 goto unreg_uart_drv;
1112 
1113         serial8250_isa_devs = platform_device_alloc("serial8250",
1114                                                     PLAT8250_DEV_LEGACY);
1115         if (!serial8250_isa_devs) {
1116                 ret = -ENOMEM;
1117                 goto unreg_pnp;
1118         }
1119 
1120         ret = platform_device_add(serial8250_isa_devs);
1121         if (ret)
1122                 goto put_dev;
1123 
1124         serial8250_register_ports(&serial8250_reg, &serial8250_isa_devs->dev);
1125 
1126         ret = platform_driver_register(&serial8250_isa_driver);
1127         if (ret == 0)
1128                 goto out;
1129 
1130         platform_device_del(serial8250_isa_devs);
1131 put_dev:
1132         platform_device_put(serial8250_isa_devs);
1133 unreg_pnp:
1134         serial8250_pnp_exit();
1135 unreg_uart_drv:
1136 #ifdef CONFIG_SPARC
1137         sunserial_unregister_minors(&serial8250_reg, UART_NR);
1138 #else
1139         uart_unregister_driver(&serial8250_reg);
1140 #endif
1141 out:
1142         return ret;
1143 }
1144 
1145 static void __exit serial8250_exit(void)
1146 {
1147         struct platform_device *isa_dev = serial8250_isa_devs;
1148 
1149         /*
1150          * This tells serial8250_unregister_port() not to re-register
1151          * the ports (thereby making serial8250_isa_driver permanently
1152          * in use.)
1153          */
1154         serial8250_isa_devs = NULL;
1155 
1156         platform_driver_unregister(&serial8250_isa_driver);
1157         platform_device_unregister(isa_dev);
1158 
1159         serial8250_pnp_exit();
1160 
1161 #ifdef CONFIG_SPARC
1162         sunserial_unregister_minors(&serial8250_reg, UART_NR);
1163 #else
1164         uart_unregister_driver(&serial8250_reg);
1165 #endif
1166 }
1167 
1168 module_init(serial8250_init);
1169 module_exit(serial8250_exit);
1170 
1171 EXPORT_SYMBOL(serial8250_suspend_port);
1172 EXPORT_SYMBOL(serial8250_resume_port);
1173 
1174 MODULE_LICENSE("GPL");
1175 MODULE_DESCRIPTION("Generic 8250/16x50 serial driver");
1176 
1177 module_param(share_irqs, uint, 0644);
1178 MODULE_PARM_DESC(share_irqs, "Share IRQs with other non-8250/16x50 devices"
1179         " (unsafe)");
1180 
1181 module_param(nr_uarts, uint, 0644);
1182 MODULE_PARM_DESC(nr_uarts, "Maximum number of UARTs supported. (1-" __MODULE_STRING(CONFIG_SERIAL_8250_NR_UARTS) ")");
1183 
1184 module_param(skip_txen_test, uint, 0644);
1185 MODULE_PARM_DESC(skip_txen_test, "Skip checking for the TXEN bug at init time");
1186 
1187 #ifdef CONFIG_SERIAL_8250_RSA
1188 module_param_array(probe_rsa, ulong, &probe_rsa_count, 0444);
1189 MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");
1190 #endif
1191 MODULE_ALIAS_CHARDEV_MAJOR(TTY_MAJOR);
1192 
1193 #ifdef CONFIG_SERIAL_8250_DEPRECATED_OPTIONS
1194 #ifndef MODULE
1195 /* This module was renamed to 8250_core in 3.7.  Keep the old "8250" name
1196  * working as well for the module options so we don't break people.  We
1197  * need to keep the names identical and the convenient macros will happily
1198  * refuse to let us do that by failing the build with redefinition errors
1199  * of global variables.  So we stick them inside a dummy function to avoid
1200  * those conflicts.  The options still get parsed, and the redefined
1201  * MODULE_PARAM_PREFIX lets us keep the "8250." syntax alive.
1202  *
1203  * This is hacky.  I'm sorry.
1204  */
1205 static void __used s8250_options(void)
1206 {
1207 #undef MODULE_PARAM_PREFIX
1208 #define MODULE_PARAM_PREFIX "8250_core."
1209 
1210         module_param_cb(share_irqs, &param_ops_uint, &share_irqs, 0644);
1211         module_param_cb(nr_uarts, &param_ops_uint, &nr_uarts, 0644);
1212         module_param_cb(skip_txen_test, &param_ops_uint, &skip_txen_test, 0644);
1213 #ifdef CONFIG_SERIAL_8250_RSA
1214         __module_param_call(MODULE_PARAM_PREFIX, probe_rsa,
1215                 &param_array_ops, .arr = &__param_arr_probe_rsa,
1216                 0444, -1, 0);
1217 #endif
1218 }
1219 #else
1220 MODULE_ALIAS("8250_core");
1221 #endif
1222 #endif
1223 

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