drivers/tty/serial/8250/8250

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This source file includes following definitions.
serial8250_interrupt
serial_do_unlink
serial_link_irq_chain
serial_unlink_irq_chain
serial8250_timeout
serial8250_backup_timeout
univ8250_setup_irq
univ8250_release_irq
serial8250_request_rsa_resource
serial8250_release_rsa_resource
serial8250_get_port
serial8250_set_isa_configurator
univ8250_config_port
univ8250_request_port
univ8250_release_port
univ8250_rsa_support
serial8250_apply_quirks
serial8250_isa_init_ports
serial8250_register_ports
univ8250_console_write
univ8250_console_setup
univ8250_console_match
univ8250_console_init
early_serial_setup
serial8250_suspend_port
serial8250_resume_port
serial8250_probe
serial8250_remove
serial8250_suspend
serial8250_resume
serial8250_find_match_or_unused
serial_8250_overrun_backoff_work
serial8250_register_8250_port
serial8250_unregister_port
serial8250_init
serial8250_exit
s8250_options
   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *  Universal/legacy driver for 8250/16550-type serial ports
   4  *
   5  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
   6  *
   7  *  Copyright (C) 2001 Russell King.
   8  *
   9  *  Supports: ISA-compatible 8250/16550 ports
  10  *            PNP 8250/16550 ports
  11  *            early_serial_setup() ports
  12  *            userspace-configurable "phantom" ports
  13  *            "serial8250" platform devices
  14  *            serial8250_register_8250_port() ports
  15  */
  16 
  17 #include <linux/acpi.h>
  18 #include <linux/module.h>
  19 #include <linux/moduleparam.h>
  20 #include <linux/ioport.h>
  21 #include <linux/init.h>
  22 #include <linux/console.h>
  23 #include <linux/sysrq.h>
  24 #include <linux/delay.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/tty.h>
  27 #include <linux/ratelimit.h>
  28 #include <linux/tty_flip.h>
  29 #include <linux/serial.h>
  30 #include <linux/serial_8250.h>
  31 #include <linux/nmi.h>
  32 #include <linux/mutex.h>
  33 #include <linux/slab.h>
  34 #include <linux/uaccess.h>
  35 #include <linux/pm_runtime.h>
  36 #include <linux/io.h>
  37 #ifdef CONFIG_SPARC
  38 #include <linux/sunserialcore.h>
  39 #endif
  40 
  41 #include <asm/irq.h>
  42 
  43 #include "8250.h"
  44 
  45 /*
  46  * Configuration:
  47  *   share_irqs - whether we pass IRQF_SHARED to request_irq().  This option
  48  *                is unsafe when used on edge-triggered interrupts.
  49  */
  50 static unsigned int share_irqs = SERIAL8250_SHARE_IRQS;
  51 
  52 static unsigned int nr_uarts = CONFIG_SERIAL_8250_RUNTIME_UARTS;
  53 
  54 static struct uart_driver serial8250_reg;
  55 
  56 static unsigned int skip_txen_test; /* force skip of txen test at init time */
  57 
  58 #define PASS_LIMIT      512
  59 
  60 #include <asm/serial.h>
  61 /*
  62  * SERIAL_PORT_DFNS tells us about built-in ports that have no
  63  * standard enumeration mechanism.   Platforms that can find all
  64  * serial ports via mechanisms like ACPI or PCI need not supply it.
  65  */
  66 #ifndef SERIAL_PORT_DFNS
  67 #define SERIAL_PORT_DFNS
  68 #endif
  69 
  70 static const struct old_serial_port old_serial_port[] = {
  71         SERIAL_PORT_DFNS /* defined in asm/serial.h */
  72 };
  73 
  74 #define UART_NR CONFIG_SERIAL_8250_NR_UARTS
  75 
  76 #ifdef CONFIG_SERIAL_8250_RSA
  77 
  78 #define PORT_RSA_MAX 4
  79 static unsigned long probe_rsa[PORT_RSA_MAX];
  80 static unsigned int probe_rsa_count;
  81 #endif /* CONFIG_SERIAL_8250_RSA  */
  82 
  83 struct irq_info {
  84         struct                  hlist_node node;
  85         int                     irq;
  86         spinlock_t              lock;   /* Protects list not the hash */
  87         struct list_head        *head;
  88 };
  89 
  90 #define NR_IRQ_HASH             32      /* Can be adjusted later */
  91 static struct hlist_head irq_lists[NR_IRQ_HASH];
  92 static DEFINE_MUTEX(hash_mutex);        /* Used to walk the hash */
  93 
  94 /*
  95  * This is the serial driver's interrupt routine.
  96  *
  97  * Arjan thinks the old way was overly complex, so it got simplified.
  98  * Alan disagrees, saying that need the complexity to handle the weird
  99  * nature of ISA shared interrupts.  (This is a special exception.)
 100  *
 101  * In order to handle ISA shared interrupts properly, we need to check
 102  * that all ports have been serviced, and therefore the ISA interrupt
 103  * line has been de-asserted.
 104  *
 105  * This means we need to loop through all ports. checking that they
 106  * don't have an interrupt pending.
 107  */
 108 static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
 109 {
 110         struct irq_info *i = dev_id;
 111         struct list_head *l, *end = NULL;
 112         int pass_counter = 0, handled = 0;
 113 
 114         pr_debug("%s(%d): start\n", __func__, irq);
 115 
 116         spin_lock(&i->lock);
 117 
 118         l = i->head;
 119         do {
 120                 struct uart_8250_port *up;
 121                 struct uart_port *port;
 122 
 123                 up = list_entry(l, struct uart_8250_port, list);
 124                 port = &up->port;
 125 
 126                 if (port->handle_irq(port)) {
 127                         handled = 1;
 128                         end = NULL;
 129                 } else if (end == NULL)
 130                         end = l;
 131 
 132                 l = l->next;
 133 
 134                 if (l == i->head && pass_counter++ > PASS_LIMIT)
 135                         break;
 136         } while (l != end);
 137 
 138         spin_unlock(&i->lock);
 139 
 140         pr_debug("%s(%d): end\n", __func__, irq);
 141 
 142         return IRQ_RETVAL(handled);
 143 }
 144 
 145 /*
 146  * To support ISA shared interrupts, we need to have one interrupt
 147  * handler that ensures that the IRQ line has been deasserted
 148  * before returning.  Failing to do this will result in the IRQ
 149  * line being stuck active, and, since ISA irqs are edge triggered,
 150  * no more IRQs will be seen.
 151  */
 152 static void serial_do_unlink(struct irq_info *i, struct uart_8250_port *up)
 153 {
 154         spin_lock_irq(&i->lock);
 155 
 156         if (!list_empty(i->head)) {
 157                 if (i->head == &up->list)
 158                         i->head = i->head->next;
 159                 list_del(&up->list);
 160         } else {
 161                 BUG_ON(i->head != &up->list);
 162                 i->head = NULL;
 163         }
 164         spin_unlock_irq(&i->lock);
 165         /* List empty so throw away the hash node */
 166         if (i->head == NULL) {
 167                 hlist_del(&i->node);
 168                 kfree(i);
 169         }
 170 }
 171 
 172 static int serial_link_irq_chain(struct uart_8250_port *up)
 173 {
 174         struct hlist_head *h;
 175         struct hlist_node *n;
 176         struct irq_info *i;
 177         int ret;
 178 
 179         mutex_lock(&hash_mutex);
 180 
 181         h = &irq_lists[up->port.irq % NR_IRQ_HASH];
 182 
 183         hlist_for_each(n, h) {
 184                 i = hlist_entry(n, struct irq_info, node);
 185                 if (i->irq == up->port.irq)
 186                         break;
 187         }
 188 
 189         if (n == NULL) {
 190                 i = kzalloc(sizeof(struct irq_info), GFP_KERNEL);
 191                 if (i == NULL) {
 192                         mutex_unlock(&hash_mutex);
 193                         return -ENOMEM;
 194                 }
 195                 spin_lock_init(&i->lock);
 196                 i->irq = up->port.irq;
 197                 hlist_add_head(&i->node, h);
 198         }
 199         mutex_unlock(&hash_mutex);
 200 
 201         spin_lock_irq(&i->lock);
 202 
 203         if (i->head) {
 204                 list_add(&up->list, i->head);
 205                 spin_unlock_irq(&i->lock);
 206 
 207                 ret = 0;
 208         } else {
 209                 INIT_LIST_HEAD(&up->list);
 210                 i->head = &up->list;
 211                 spin_unlock_irq(&i->lock);
 212                 ret = request_irq(up->port.irq, serial8250_interrupt,
 213                                   up->port.irqflags, up->port.name, i);
 214                 if (ret < 0)
 215                         serial_do_unlink(i, up);
 216         }
 217 
 218         return ret;
 219 }
 220 
 221 static void serial_unlink_irq_chain(struct uart_8250_port *up)
 222 {
 223         /*
 224          * yes, some broken gcc emit "warning: 'i' may be used uninitialized"
 225          * but no, we are not going to take a patch that assigns NULL below.
 226          */
 227         struct irq_info *i;
 228         struct hlist_node *n;
 229         struct hlist_head *h;
 230 
 231         mutex_lock(&hash_mutex);
 232 
 233         h = &irq_lists[up->port.irq % NR_IRQ_HASH];
 234 
 235         hlist_for_each(n, h) {
 236                 i = hlist_entry(n, struct irq_info, node);
 237                 if (i->irq == up->port.irq)
 238                         break;
 239         }
 240 
 241         BUG_ON(n == NULL);
 242         BUG_ON(i->head == NULL);
 243 
 244         if (list_empty(i->head))
 245                 free_irq(up->port.irq, i);
 246 
 247         serial_do_unlink(i, up);
 248         mutex_unlock(&hash_mutex);
 249 }
 250 
 251 /*
 252  * This function is used to handle ports that do not have an
 253  * interrupt.  This doesn't work very well for 16450's, but gives
 254  * barely passable results for a 16550A.  (Although at the expense
 255  * of much CPU overhead).
 256  */
 257 static void serial8250_timeout(struct timer_list *t)
 258 {
 259         struct uart_8250_port *up = from_timer(up, t, timer);
 260 
 261         up->port.handle_irq(&up->port);
 262         mod_timer(&up->timer, jiffies + uart_poll_timeout(&up->port));
 263 }
 264 
 265 static void serial8250_backup_timeout(struct timer_list *t)
 266 {
 267         struct uart_8250_port *up = from_timer(up, t, timer);
 268         unsigned int iir, ier = 0, lsr;
 269         unsigned long flags;
 270 
 271         spin_lock_irqsave(&up->port.lock, flags);
 272 
 273         /*
 274          * Must disable interrupts or else we risk racing with the interrupt
 275          * based handler.
 276          */
 277         if (up->port.irq) {
 278                 ier = serial_in(up, UART_IER);
 279                 serial_out(up, UART_IER, 0);
 280         }
 281 
 282         iir = serial_in(up, UART_IIR);
 283 
 284         /*
 285          * This should be a safe test for anyone who doesn't trust the
 286          * IIR bits on their UART, but it's specifically designed for
 287          * the "Diva" UART used on the management processor on many HP
 288          * ia64 and parisc boxes.
 289          */
 290         lsr = serial_in(up, UART_LSR);
 291         up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
 292         if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
 293             (!uart_circ_empty(&up->port.state->xmit) || up->port.x_char) &&
 294             (lsr & UART_LSR_THRE)) {
 295                 iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
 296                 iir |= UART_IIR_THRI;
 297         }
 298 
 299         if (!(iir & UART_IIR_NO_INT))
 300                 serial8250_tx_chars(up);
 301 
 302         if (up->port.irq)
 303                 serial_out(up, UART_IER, ier);
 304 
 305         spin_unlock_irqrestore(&up->port.lock, flags);
 306 
 307         /* Standard timer interval plus 0.2s to keep the port running */
 308         mod_timer(&up->timer,
 309                 jiffies + uart_poll_timeout(&up->port) + HZ / 5);
 310 }
 311 
 312 static int univ8250_setup_irq(struct uart_8250_port *up)
 313 {
 314         struct uart_port *port = &up->port;
 315         int retval = 0;
 316 
 317         /*
 318          * The above check will only give an accurate result the first time
 319          * the port is opened so this value needs to be preserved.
 320          */
 321         if (up->bugs & UART_BUG_THRE) {
 322                 pr_debug("%s - using backup timer\n", port->name);
 323 
 324                 up->timer.function = serial8250_backup_timeout;
 325                 mod_timer(&up->timer, jiffies +
 326                           uart_poll_timeout(port) + HZ / 5);
 327         }
 328 
 329         /*
 330          * If the "interrupt" for this port doesn't correspond with any
 331          * hardware interrupt, we use a timer-based system.  The original
 332          * driver used to do this with IRQ0.
 333          */
 334         if (!port->irq) {
 335                 mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
 336         } else
 337                 retval = serial_link_irq_chain(up);
 338 
 339         return retval;
 340 }
 341 
 342 static void univ8250_release_irq(struct uart_8250_port *up)
 343 {
 344         struct uart_port *port = &up->port;
 345 
 346         del_timer_sync(&up->timer);
 347         up->timer.function = serial8250_timeout;
 348         if (port->irq)
 349                 serial_unlink_irq_chain(up);
 350 }
 351 
 352 #ifdef CONFIG_SERIAL_8250_RSA
 353 static int serial8250_request_rsa_resource(struct uart_8250_port *up)
 354 {
 355         unsigned long start = UART_RSA_BASE << up->port.regshift;
 356         unsigned int size = 8 << up->port.regshift;
 357         struct uart_port *port = &up->port;
 358         int ret = -EINVAL;
 359 
 360         switch (port->iotype) {
 361         case UPIO_HUB6:
 362         case UPIO_PORT:
 363                 start += port->iobase;
 364                 if (request_region(start, size, "serial-rsa"))
 365                         ret = 0;
 366                 else
 367                         ret = -EBUSY;
 368                 break;
 369         }
 370 
 371         return ret;
 372 }
 373 
 374 static void serial8250_release_rsa_resource(struct uart_8250_port *up)
 375 {
 376         unsigned long offset = UART_RSA_BASE << up->port.regshift;
 377         unsigned int size = 8 << up->port.regshift;
 378         struct uart_port *port = &up->port;
 379 
 380         switch (port->iotype) {
 381         case UPIO_HUB6:
 382         case UPIO_PORT:
 383                 release_region(port->iobase + offset, size);
 384                 break;
 385         }
 386 }
 387 #endif
 388 
 389 static const struct uart_ops *base_ops;
 390 static struct uart_ops univ8250_port_ops;
 391 
 392 static const struct uart_8250_ops univ8250_driver_ops = {
 393         .setup_irq      = univ8250_setup_irq,
 394         .release_irq    = univ8250_release_irq,
 395 };
 396 
 397 static struct uart_8250_port serial8250_ports[UART_NR];
 398 
 399 /**
 400  * serial8250_get_port - retrieve struct uart_8250_port
 401  * @line: serial line number
 402  *
 403  * This function retrieves struct uart_8250_port for the specific line.
 404  * This struct *must* *not* be used to perform a 8250 or serial core operation
 405  * which is not accessible otherwise. Its only purpose is to make the struct
 406  * accessible to the runtime-pm callbacks for context suspend/restore.
 407  * The lock assumption made here is none because runtime-pm suspend/resume
 408  * callbacks should not be invoked if there is any operation performed on the
 409  * port.
 410  */
 411 struct uart_8250_port *serial8250_get_port(int line)
 412 {
 413         return &serial8250_ports[line];
 414 }
 415 EXPORT_SYMBOL_GPL(serial8250_get_port);
 416 
 417 static void (*serial8250_isa_config)(int port, struct uart_port *up,
 418         u32 *capabilities);
 419 
 420 void serial8250_set_isa_configurator(
 421         void (*v)(int port, struct uart_port *up, u32 *capabilities))
 422 {
 423         serial8250_isa_config = v;
 424 }
 425 EXPORT_SYMBOL(serial8250_set_isa_configurator);
 426 
 427 #ifdef CONFIG_SERIAL_8250_RSA
 428 
 429 static void univ8250_config_port(struct uart_port *port, int flags)
 430 {
 431         struct uart_8250_port *up = up_to_u8250p(port);
 432 
 433         up->probe &= ~UART_PROBE_RSA;
 434         if (port->type == PORT_RSA) {
 435                 if (serial8250_request_rsa_resource(up) == 0)
 436                         up->probe |= UART_PROBE_RSA;
 437         } else if (flags & UART_CONFIG_TYPE) {
 438                 int i;
 439 
 440                 for (i = 0; i < probe_rsa_count; i++) {
 441                         if (probe_rsa[i] == up->port.iobase) {
 442                                 if (serial8250_request_rsa_resource(up) == 0)
 443                                         up->probe |= UART_PROBE_RSA;
 444                                 break;
 445                         }
 446                 }
 447         }
 448 
 449         base_ops->config_port(port, flags);
 450 
 451         if (port->type != PORT_RSA && up->probe & UART_PROBE_RSA)
 452                 serial8250_release_rsa_resource(up);
 453 }
 454 
 455 static int univ8250_request_port(struct uart_port *port)
 456 {
 457         struct uart_8250_port *up = up_to_u8250p(port);
 458         int ret;
 459 
 460         ret = base_ops->request_port(port);
 461         if (ret == 0 && port->type == PORT_RSA) {
 462                 ret = serial8250_request_rsa_resource(up);
 463                 if (ret < 0)
 464                         base_ops->release_port(port);
 465         }
 466 
 467         return ret;
 468 }
 469 
 470 static void univ8250_release_port(struct uart_port *port)
 471 {
 472         struct uart_8250_port *up = up_to_u8250p(port);
 473 
 474         if (port->type == PORT_RSA)
 475                 serial8250_release_rsa_resource(up);
 476         base_ops->release_port(port);
 477 }
 478 
 479 static void univ8250_rsa_support(struct uart_ops *ops)
 480 {
 481         ops->config_port  = univ8250_config_port;
 482         ops->request_port = univ8250_request_port;
 483         ops->release_port = univ8250_release_port;
 484 }
 485 
 486 #else
 487 #define univ8250_rsa_support(x)         do { } while (0)
 488 #endif /* CONFIG_SERIAL_8250_RSA */
 489 
 490 static inline void serial8250_apply_quirks(struct uart_8250_port *up)
 491 {
 492         up->port.quirks |= skip_txen_test ? UPQ_NO_TXEN_TEST : 0;
 493 }
 494 
 495 static void __init serial8250_isa_init_ports(void)
 496 {
 497         struct uart_8250_port *up;
 498         static int first = 1;
 499         int i, irqflag = 0;
 500 
 501         if (!first)
 502                 return;
 503         first = 0;
 504 
 505         if (nr_uarts > UART_NR)
 506                 nr_uarts = UART_NR;
 507 
 508         for (i = 0; i < nr_uarts; i++) {
 509                 struct uart_8250_port *up = &serial8250_ports[i];
 510                 struct uart_port *port = &up->port;
 511 
 512                 port->line = i;
 513                 serial8250_init_port(up);
 514                 if (!base_ops)
 515                         base_ops = port->ops;
 516                 port->ops = &univ8250_port_ops;
 517 
 518                 timer_setup(&up->timer, serial8250_timeout, 0);
 519 
 520                 up->ops = &univ8250_driver_ops;
 521 
 522                 /*
 523                  * ALPHA_KLUDGE_MCR needs to be killed.
 524                  */
 525                 up->mcr_mask = ~ALPHA_KLUDGE_MCR;
 526                 up->mcr_force = ALPHA_KLUDGE_MCR;
 527         }
 528 
 529         /* chain base port ops to support Remote Supervisor Adapter */
 530         univ8250_port_ops = *base_ops;
 531         univ8250_rsa_support(&univ8250_port_ops);
 532 
 533         if (share_irqs)
 534                 irqflag = IRQF_SHARED;
 535 
 536         for (i = 0, up = serial8250_ports;
 537              i < ARRAY_SIZE(old_serial_port) && i < nr_uarts;
 538              i++, up++) {
 539                 struct uart_port *port = &up->port;
 540 
 541                 port->iobase   = old_serial_port[i].port;
 542                 port->irq      = irq_canonicalize(old_serial_port[i].irq);
 543                 port->irqflags = 0;
 544                 port->uartclk  = old_serial_port[i].baud_base * 16;
 545                 port->flags    = old_serial_port[i].flags;
 546                 port->hub6     = 0;
 547                 port->membase  = old_serial_port[i].iomem_base;
 548                 port->iotype   = old_serial_port[i].io_type;
 549                 port->regshift = old_serial_port[i].iomem_reg_shift;
 550                 serial8250_set_defaults(up);
 551 
 552                 port->irqflags |= irqflag;
 553                 if (serial8250_isa_config != NULL)
 554                         serial8250_isa_config(i, &up->port, &up->capabilities);
 555         }
 556 }
 557 
 558 static void __init
 559 serial8250_register_ports(struct uart_driver *drv, struct device *dev)
 560 {
 561         int i;
 562 
 563         for (i = 0; i < nr_uarts; i++) {
 564                 struct uart_8250_port *up = &serial8250_ports[i];
 565 
 566                 if (up->port.type == PORT_8250_CIR)
 567                         continue;
 568 
 569                 if (up->port.dev)
 570                         continue;
 571 
 572                 up->port.dev = dev;
 573 
 574                 serial8250_apply_quirks(up);
 575                 uart_add_one_port(drv, &up->port);
 576         }
 577 }
 578 
 579 #ifdef CONFIG_SERIAL_8250_CONSOLE
 580 
 581 static void univ8250_console_write(struct console *co, const char *s,
 582                                    unsigned int count)
 583 {
 584         struct uart_8250_port *up = &serial8250_ports[co->index];
 585 
 586         serial8250_console_write(up, s, count);
 587 }
 588 
 589 static int univ8250_console_setup(struct console *co, char *options)
 590 {
 591         struct uart_port *port;
 592         int retval;
 593 
 594         /*
 595          * Check whether an invalid uart number has been specified, and
 596          * if so, search for the first available port that does have
 597          * console support.
 598          */
 599         if (co->index >= nr_uarts)
 600                 co->index = 0;
 601         port = &serial8250_ports[co->index].port;
 602         /* link port to console */
 603         port->cons = co;
 604 
 605         retval = serial8250_console_setup(port, options, false);
 606         if (retval != 0)
 607                 port->cons = NULL;
 608         return retval;
 609 }
 610 
 611 /**
 612  *      univ8250_console_match - non-standard console matching
 613  *      @co:      registering console
 614  *      @name:    name from console command line
 615  *      @idx:     index from console command line
 616  *      @options: ptr to option string from console command line
 617  *
 618  *      Only attempts to match console command lines of the form:
 619  *          console=uart[8250],io|mmio|mmio16|mmio32,<addr>[,<options>]
 620  *          console=uart[8250],0x<addr>[,<options>]
 621  *      This form is used to register an initial earlycon boot console and
 622  *      replace it with the serial8250_console at 8250 driver init.
 623  *
 624  *      Performs console setup for a match (as required by interface)
 625  *      If no <options> are specified, then assume the h/w is already setup.
 626  *
 627  *      Returns 0 if console matches; otherwise non-zero to use default matching
 628  */
 629 static int univ8250_console_match(struct console *co, char *name, int idx,
 630                                   char *options)
 631 {
 632         char match[] = "uart";  /* 8250-specific earlycon name */
 633         unsigned char iotype;
 634         resource_size_t addr;
 635         int i;
 636 
 637         if (strncmp(name, match, 4) != 0)
 638                 return -ENODEV;
 639 
 640         if (uart_parse_earlycon(options, &iotype, &addr, &options))
 641                 return -ENODEV;
 642 
 643         /* try to match the port specified on the command line */
 644         for (i = 0; i < nr_uarts; i++) {
 645                 struct uart_port *port = &serial8250_ports[i].port;
 646 
 647                 if (port->iotype != iotype)
 648                         continue;
 649                 if ((iotype == UPIO_MEM || iotype == UPIO_MEM16 ||
 650                      iotype == UPIO_MEM32 || iotype == UPIO_MEM32BE)
 651                     && (port->mapbase != addr))
 652                         continue;
 653                 if (iotype == UPIO_PORT && port->iobase != addr)
 654                         continue;
 655 
 656                 co->index = i;
 657                 port->cons = co;
 658                 return serial8250_console_setup(port, options, true);
 659         }
 660 
 661         return -ENODEV;
 662 }
 663 
 664 static struct console univ8250_console = {
 665         .name           = "ttyS",
 666         .write          = univ8250_console_write,
 667         .device         = uart_console_device,
 668         .setup          = univ8250_console_setup,
 669         .match          = univ8250_console_match,
 670         .flags          = CON_PRINTBUFFER | CON_ANYTIME,
 671         .index          = -1,
 672         .data           = &serial8250_reg,
 673 };
 674 
 675 static int __init univ8250_console_init(void)
 676 {
 677         if (nr_uarts == 0)
 678                 return -ENODEV;
 679 
 680         serial8250_isa_init_ports();
 681         register_console(&univ8250_console);
 682         return 0;
 683 }
 684 console_initcall(univ8250_console_init);
 685 
 686 #define SERIAL8250_CONSOLE      (&univ8250_console)
 687 #else
 688 #define SERIAL8250_CONSOLE      NULL
 689 #endif
 690 
 691 static struct uart_driver serial8250_reg = {
 692         .owner                  = THIS_MODULE,
 693         .driver_name            = "serial",
 694         .dev_name               = "ttyS",
 695         .major                  = TTY_MAJOR,
 696         .minor                  = 64,
 697         .cons                   = SERIAL8250_CONSOLE,
 698 };
 699 
 700 /*
 701  * early_serial_setup - early registration for 8250 ports
 702  *
 703  * Setup an 8250 port structure prior to console initialisation.  Use
 704  * after console initialisation will cause undefined behaviour.
 705  */
 706 int __init early_serial_setup(struct uart_port *port)
 707 {
 708         struct uart_port *p;
 709 
 710         if (port->line >= ARRAY_SIZE(serial8250_ports) || nr_uarts == 0)
 711                 return -ENODEV;
 712 
 713         serial8250_isa_init_ports();
 714         p = &serial8250_ports[port->line].port;
 715         p->iobase       = port->iobase;
 716         p->membase      = port->membase;
 717         p->irq          = port->irq;
 718         p->irqflags     = port->irqflags;
 719         p->uartclk      = port->uartclk;
 720         p->fifosize     = port->fifosize;
 721         p->regshift     = port->regshift;
 722         p->iotype       = port->iotype;
 723         p->flags        = port->flags;
 724         p->mapbase      = port->mapbase;
 725         p->mapsize      = port->mapsize;
 726         p->private_data = port->private_data;
 727         p->type         = port->type;
 728         p->line         = port->line;
 729 
 730         serial8250_set_defaults(up_to_u8250p(p));
 731 
 732         if (port->serial_in)
 733                 p->serial_in = port->serial_in;
 734         if (port->serial_out)
 735                 p->serial_out = port->serial_out;
 736         if (port->handle_irq)
 737                 p->handle_irq = port->handle_irq;
 738 
 739         return 0;
 740 }
 741 
 742 /**
 743  *      serial8250_suspend_port - suspend one serial port
 744  *      @line:  serial line number
 745  *
 746  *      Suspend one serial port.
 747  */
 748 void serial8250_suspend_port(int line)
 749 {
 750         struct uart_8250_port *up = &serial8250_ports[line];
 751         struct uart_port *port = &up->port;
 752 
 753         if (!console_suspend_enabled && uart_console(port) &&
 754             port->type != PORT_8250) {
 755                 unsigned char canary = 0xa5;
 756                 serial_out(up, UART_SCR, canary);
 757                 if (serial_in(up, UART_SCR) == canary)
 758                         up->canary = canary;
 759         }
 760 
 761         uart_suspend_port(&serial8250_reg, port);
 762 }
 763 EXPORT_SYMBOL(serial8250_suspend_port);
 764 
 765 /**
 766  *      serial8250_resume_port - resume one serial port
 767  *      @line:  serial line number
 768  *
 769  *      Resume one serial port.
 770  */
 771 void serial8250_resume_port(int line)
 772 {
 773         struct uart_8250_port *up = &serial8250_ports[line];
 774         struct uart_port *port = &up->port;
 775 
 776         up->canary = 0;
 777 
 778         if (up->capabilities & UART_NATSEMI) {
 779                 /* Ensure it's still in high speed mode */
 780                 serial_port_out(port, UART_LCR, 0xE0);
 781 
 782                 ns16550a_goto_highspeed(up);
 783 
 784                 serial_port_out(port, UART_LCR, 0);
 785                 port->uartclk = 921600*16;
 786         }
 787         uart_resume_port(&serial8250_reg, port);
 788 }
 789 EXPORT_SYMBOL(serial8250_resume_port);
 790 
 791 /*
 792  * Register a set of serial devices attached to a platform device.  The
 793  * list is terminated with a zero flags entry, which means we expect
 794  * all entries to have at least UPF_BOOT_AUTOCONF set.
 795  */
 796 static int serial8250_probe(struct platform_device *dev)
 797 {
 798         struct plat_serial8250_port *p = dev_get_platdata(&dev->dev);
 799         struct uart_8250_port uart;
 800         int ret, i, irqflag = 0;
 801 
 802         memset(&uart, 0, sizeof(uart));
 803 
 804         if (share_irqs)
 805                 irqflag = IRQF_SHARED;
 806 
 807         for (i = 0; p && p->flags != 0; p++, i++) {
 808                 uart.port.iobase        = p->iobase;
 809                 uart.port.membase       = p->membase;
 810                 uart.port.irq           = p->irq;
 811                 uart.port.irqflags      = p->irqflags;
 812                 uart.port.uartclk       = p->uartclk;
 813                 uart.port.regshift      = p->regshift;
 814                 uart.port.iotype        = p->iotype;
 815                 uart.port.flags         = p->flags;
 816                 uart.port.mapbase       = p->mapbase;
 817                 uart.port.hub6          = p->hub6;
 818                 uart.port.private_data  = p->private_data;
 819                 uart.port.type          = p->type;
 820                 uart.port.serial_in     = p->serial_in;
 821                 uart.port.serial_out    = p->serial_out;
 822                 uart.port.handle_irq    = p->handle_irq;
 823                 uart.port.handle_break  = p->handle_break;
 824                 uart.port.set_termios   = p->set_termios;
 825                 uart.port.set_ldisc     = p->set_ldisc;
 826                 uart.port.get_mctrl     = p->get_mctrl;
 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 static void serial_8250_overrun_backoff_work(struct work_struct *work)
 946 {
 947         struct uart_8250_port *up =
 948             container_of(to_delayed_work(work), struct uart_8250_port,
 949                          overrun_backoff);
 950         struct uart_port *port = &up->port;
 951         unsigned long flags;
 952 
 953         spin_lock_irqsave(&port->lock, flags);
 954         up->ier |= UART_IER_RLSI | UART_IER_RDI;
 955         up->port.read_status_mask |= UART_LSR_DR;
 956         serial_out(up, UART_IER, up->ier);
 957         spin_unlock_irqrestore(&port->lock, flags);
 958 }
 959 
 960 /**
 961  *      serial8250_register_8250_port - register a serial port
 962  *      @up: serial port template
 963  *
 964  *      Configure the serial port specified by the request. If the
 965  *      port exists and is in use, it is hung up and unregistered
 966  *      first.
 967  *
 968  *      The port is then probed and if necessary the IRQ is autodetected
 969  *      If this fails an error is returned.
 970  *
 971  *      On success the port is ready to use and the line number is returned.
 972  */
 973 int serial8250_register_8250_port(struct uart_8250_port *up)
 974 {
 975         struct uart_8250_port *uart;
 976         int ret = -ENOSPC;
 977 
 978         if (up->port.uartclk == 0)
 979                 return -EINVAL;
 980 
 981         mutex_lock(&serial_mutex);
 982 
 983         uart = serial8250_find_match_or_unused(&up->port);
 984         if (uart && uart->port.type != PORT_8250_CIR) {
 985                 struct mctrl_gpios *gpios;
 986 
 987                 if (uart->port.dev)
 988                         uart_remove_one_port(&serial8250_reg, &uart->port);
 989 
 990                 uart->port.iobase       = up->port.iobase;
 991                 uart->port.membase      = up->port.membase;
 992                 uart->port.irq          = up->port.irq;
 993                 uart->port.irqflags     = up->port.irqflags;
 994                 uart->port.uartclk      = up->port.uartclk;
 995                 uart->port.fifosize     = up->port.fifosize;
 996                 uart->port.regshift     = up->port.regshift;
 997                 uart->port.iotype       = up->port.iotype;
 998                 uart->port.flags        = up->port.flags | UPF_BOOT_AUTOCONF;
 999                 uart->bugs              = up->bugs;
1000                 uart->port.mapbase      = up->port.mapbase;
1001                 uart->port.mapsize      = up->port.mapsize;
1002                 uart->port.private_data = up->port.private_data;
1003                 uart->tx_loadsz         = up->tx_loadsz;
1004                 uart->capabilities      = up->capabilities;
1005                 uart->port.throttle     = up->port.throttle;
1006                 uart->port.unthrottle   = up->port.unthrottle;
1007                 uart->port.rs485_config = up->port.rs485_config;
1008                 uart->port.rs485        = up->port.rs485;
1009                 uart->dma               = up->dma;
1010 
1011                 /* Take tx_loadsz from fifosize if it wasn't set separately */
1012                 if (uart->port.fifosize && !uart->tx_loadsz)
1013                         uart->tx_loadsz = uart->port.fifosize;
1014 
1015                 if (up->port.dev)
1016                         uart->port.dev = up->port.dev;
1017 
1018                 if (up->port.flags & UPF_FIXED_TYPE)
1019                         uart->port.type = up->port.type;
1020 
1021                 /*
1022                  * Only call mctrl_gpio_init(), if the device has no ACPI
1023                  * companion device
1024                  */
1025                 if (!has_acpi_companion(uart->port.dev)) {
1026                         gpios = mctrl_gpio_init(&uart->port, 0);
1027                         if (IS_ERR(gpios)) {
1028                                 ret = PTR_ERR(gpios);
1029                                 goto out_unlock;
1030                         } else {
1031                                 uart->gpios = gpios;
1032                         }
1033                 }
1034 
1035                 serial8250_set_defaults(uart);
1036 
1037                 /* Possibly override default I/O functions.  */
1038                 if (up->port.serial_in)
1039                         uart->port.serial_in = up->port.serial_in;
1040                 if (up->port.serial_out)
1041                         uart->port.serial_out = up->port.serial_out;
1042                 if (up->port.handle_irq)
1043                         uart->port.handle_irq = up->port.handle_irq;
1044                 /*  Possibly override set_termios call */
1045                 if (up->port.set_termios)
1046                         uart->port.set_termios = up->port.set_termios;
1047                 if (up->port.set_ldisc)
1048                         uart->port.set_ldisc = up->port.set_ldisc;
1049                 if (up->port.get_mctrl)
1050                         uart->port.get_mctrl = up->port.get_mctrl;
1051                 if (up->port.set_mctrl)
1052                         uart->port.set_mctrl = up->port.set_mctrl;
1053                 if (up->port.get_divisor)
1054                         uart->port.get_divisor = up->port.get_divisor;
1055                 if (up->port.set_divisor)
1056                         uart->port.set_divisor = up->port.set_divisor;
1057                 if (up->port.startup)
1058                         uart->port.startup = up->port.startup;
1059                 if (up->port.shutdown)
1060                         uart->port.shutdown = up->port.shutdown;
1061                 if (up->port.pm)
1062                         uart->port.pm = up->port.pm;
1063                 if (up->port.handle_break)
1064                         uart->port.handle_break = up->port.handle_break;
1065                 if (up->dl_read)
1066                         uart->dl_read = up->dl_read;
1067                 if (up->dl_write)
1068                         uart->dl_write = up->dl_write;
1069 
1070                 if (uart->port.type != PORT_8250_CIR) {
1071                         if (serial8250_isa_config != NULL)
1072                                 serial8250_isa_config(0, &uart->port,
1073                                                 &uart->capabilities);
1074 
1075                         serial8250_apply_quirks(uart);
1076                         ret = uart_add_one_port(&serial8250_reg,
1077                                                 &uart->port);
1078                         if (ret == 0)
1079                                 ret = uart->port.line;
1080                 } else {
1081                         dev_info(uart->port.dev,
1082                                 "skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
1083                                 uart->port.iobase,
1084                                 (unsigned long long)uart->port.mapbase,
1085                                 uart->port.irq);
1086 
1087                         ret = 0;
1088                 }
1089 
1090                 /* Initialise interrupt backoff work if required */
1091                 if (up->overrun_backoff_time_ms > 0) {
1092                         uart->overrun_backoff_time_ms =
1093                                 up->overrun_backoff_time_ms;
1094                         INIT_DELAYED_WORK(&uart->overrun_backoff,
1095                                         serial_8250_overrun_backoff_work);
1096                 } else {
1097                         uart->overrun_backoff_time_ms = 0;
1098                 }
1099         }
1100 
1101 out_unlock:
1102         mutex_unlock(&serial_mutex);
1103 
1104         return ret;
1105 }
1106 EXPORT_SYMBOL(serial8250_register_8250_port);
1107 
1108 /**
1109  *      serial8250_unregister_port - remove a 16x50 serial port at runtime
1110  *      @line: serial line number
1111  *
1112  *      Remove one serial port.  This may not be called from interrupt
1113  *      context.  We hand the port back to the our control.
1114  */
1115 void serial8250_unregister_port(int line)
1116 {
1117         struct uart_8250_port *uart = &serial8250_ports[line];
1118 
1119         mutex_lock(&serial_mutex);
1120 
1121         if (uart->em485) {
1122                 unsigned long flags;
1123 
1124                 spin_lock_irqsave(&uart->port.lock, flags);
1125                 serial8250_em485_destroy(uart);
1126                 spin_unlock_irqrestore(&uart->port.lock, flags);
1127         }
1128 
1129         uart_remove_one_port(&serial8250_reg, &uart->port);
1130         if (serial8250_isa_devs) {
1131                 uart->port.flags &= ~UPF_BOOT_AUTOCONF;
1132                 uart->port.type = PORT_UNKNOWN;
1133                 uart->port.dev = &serial8250_isa_devs->dev;
1134                 uart->capabilities = 0;
1135                 serial8250_apply_quirks(uart);
1136                 uart_add_one_port(&serial8250_reg, &uart->port);
1137         } else {
1138                 uart->port.dev = NULL;
1139         }
1140         mutex_unlock(&serial_mutex);
1141 }
1142 EXPORT_SYMBOL(serial8250_unregister_port);
1143 
1144 static int __init serial8250_init(void)
1145 {
1146         int ret;
1147 
1148         if (nr_uarts == 0)
1149                 return -ENODEV;
1150 
1151         serial8250_isa_init_ports();
1152 
1153         pr_info("Serial: 8250/16550 driver, %d ports, IRQ sharing %sabled\n",
1154                 nr_uarts, share_irqs ? "en" : "dis");
1155 
1156 #ifdef CONFIG_SPARC
1157         ret = sunserial_register_minors(&serial8250_reg, UART_NR);
1158 #else
1159         serial8250_reg.nr = UART_NR;
1160         ret = uart_register_driver(&serial8250_reg);
1161 #endif
1162         if (ret)
1163                 goto out;
1164 
1165         ret = serial8250_pnp_init();
1166         if (ret)
1167                 goto unreg_uart_drv;
1168 
1169         serial8250_isa_devs = platform_device_alloc("serial8250",
1170                                                     PLAT8250_DEV_LEGACY);
1171         if (!serial8250_isa_devs) {
1172                 ret = -ENOMEM;
1173                 goto unreg_pnp;
1174         }
1175 
1176         ret = platform_device_add(serial8250_isa_devs);
1177         if (ret)
1178                 goto put_dev;
1179 
1180         serial8250_register_ports(&serial8250_reg, &serial8250_isa_devs->dev);
1181 
1182         ret = platform_driver_register(&serial8250_isa_driver);
1183         if (ret == 0)
1184                 goto out;
1185 
1186         platform_device_del(serial8250_isa_devs);
1187 put_dev:
1188         platform_device_put(serial8250_isa_devs);
1189 unreg_pnp:
1190         serial8250_pnp_exit();
1191 unreg_uart_drv:
1192 #ifdef CONFIG_SPARC
1193         sunserial_unregister_minors(&serial8250_reg, UART_NR);
1194 #else
1195         uart_unregister_driver(&serial8250_reg);
1196 #endif
1197 out:
1198         return ret;
1199 }
1200 
1201 static void __exit serial8250_exit(void)
1202 {
1203         struct platform_device *isa_dev = serial8250_isa_devs;
1204 
1205         /*
1206          * This tells serial8250_unregister_port() not to re-register
1207          * the ports (thereby making serial8250_isa_driver permanently
1208          * in use.)
1209          */
1210         serial8250_isa_devs = NULL;
1211 
1212         platform_driver_unregister(&serial8250_isa_driver);
1213         platform_device_unregister(isa_dev);
1214 
1215         serial8250_pnp_exit();
1216 
1217 #ifdef CONFIG_SPARC
1218         sunserial_unregister_minors(&serial8250_reg, UART_NR);
1219 #else
1220         uart_unregister_driver(&serial8250_reg);
1221 #endif
1222 }
1223 
1224 module_init(serial8250_init);
1225 module_exit(serial8250_exit);
1226 
1227 MODULE_LICENSE("GPL");
1228 MODULE_DESCRIPTION("Generic 8250/16x50 serial driver");
1229 
1230 module_param_hw(share_irqs, uint, other, 0644);
1231 MODULE_PARM_DESC(share_irqs, "Share IRQs with other non-8250/16x50 devices (unsafe)");
1232 
1233 module_param(nr_uarts, uint, 0644);
1234 MODULE_PARM_DESC(nr_uarts, "Maximum number of UARTs supported. (1-" __MODULE_STRING(CONFIG_SERIAL_8250_NR_UARTS) ")");
1235 
1236 module_param(skip_txen_test, uint, 0644);
1237 MODULE_PARM_DESC(skip_txen_test, "Skip checking for the TXEN bug at init time");
1238 
1239 #ifdef CONFIG_SERIAL_8250_RSA
1240 module_param_hw_array(probe_rsa, ulong, ioport, &probe_rsa_count, 0444);
1241 MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");
1242 #endif
1243 MODULE_ALIAS_CHARDEV_MAJOR(TTY_MAJOR);
1244 
1245 #ifdef CONFIG_SERIAL_8250_DEPRECATED_OPTIONS
1246 #ifndef MODULE
1247 /* This module was renamed to 8250_core in 3.7.  Keep the old "8250" name
1248  * working as well for the module options so we don't break people.  We
1249  * need to keep the names identical and the convenient macros will happily
1250  * refuse to let us do that by failing the build with redefinition errors
1251  * of global variables.  So we stick them inside a dummy function to avoid
1252  * those conflicts.  The options still get parsed, and the redefined
1253  * MODULE_PARAM_PREFIX lets us keep the "8250." syntax alive.
1254  *
1255  * This is hacky.  I'm sorry.
1256  */
1257 static void __used s8250_options(void)
1258 {
1259 #undef MODULE_PARAM_PREFIX
1260 #define MODULE_PARAM_PREFIX "8250_core."
1261 
1262         module_param_cb(share_irqs, &param_ops_uint, &share_irqs, 0644);
1263         module_param_cb(nr_uarts, &param_ops_uint, &nr_uarts, 0644);
1264         module_param_cb(skip_txen_test, &param_ops_uint, &skip_txen_test, 0644);
1265 #ifdef CONFIG_SERIAL_8250_RSA
1266         __module_param_call(MODULE_PARAM_PREFIX, probe_rsa,
1267                 &param_array_ops, .arr = &__param_arr_probe_rsa,
1268                 0444, -1, 0);
1269 #endif
1270 }
1271 #else
1272 MODULE_ALIAS("8250_core");
1273 #endif
1274 #endif
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root/drivers/tty/serial/8250/8250_core.c

DEFINITIONS
