arch/ia64/hp/sim/simserial.c

   1 /*
   2  * Simulated Serial Driver (fake serial)
   3  *
   4  * This driver is mostly used for bringup purposes and will go away.
   5  * It has a strong dependency on the system console. All outputs
   6  * are rerouted to the same facility as the one used by printk which, in our
   7  * case means sys_sim.c console (goes via the simulator). The code hereafter
   8  * is completely leveraged from the serial.c driver.
   9  *
  10  * Copyright (C) 1999-2000, 2002-2003 Hewlett-Packard Co
  11  *      Stephane Eranian <eranian@hpl.hp.com>
  12  *      David Mosberger-Tang <davidm@hpl.hp.com>
  13  *
  14  * 02/04/00 D. Mosberger        Merged in serial.c bug fixes in rs_close().
  15  * 02/25/00 D. Mosberger        Synced up with 2.3.99pre-5 version of serial.c.
  16  * 07/30/02 D. Mosberger        Replace sti()/cli() with explicit spinlocks & local irq masking
  17  */
  18
  19 #include <linux/init.h>
  20 #include <linux/errno.h>
  21 #include <linux/sched.h>
  22 #include <linux/tty.h>
  23 #include <linux/tty_flip.h>
  24 #include <linux/major.h>
  25 #include <linux/fcntl.h>
  26 #include <linux/mm.h>
  27 #include <linux/seq_file.h>
  28 #include <linux/slab.h>
  29 #include <linux/capability.h>
  30 #include <linux/circ_buf.h>
  31 #include <linux/console.h>
  32 #include <linux/module.h>
  33 #include <linux/serial.h>
  34 #include <linux/sysrq.h>
  35
  36 #include <asm/irq.h>
  37 #include <asm/hpsim.h>
  38 #include <asm/hw_irq.h>
  39 #include <asm/uaccess.h>
  40
  41 #include "hpsim_ssc.h"
  42
  43 #undef SIMSERIAL_DEBUG  /* define this to get some debug information */
  44
  45 #define KEYBOARD_INTR   3       /* must match with simulator! */
  46
  47 #define NR_PORTS        1       /* only one port for now */
  48
  49 struct serial_state {
  50         struct tty_port port;
  51         struct circ_buf xmit;
  52         int irq;
  53         int x_char;
  54 };
  55
  56 static char *serial_name = "SimSerial driver";
  57 static char *serial_version = "0.6";
  58
  59 static struct serial_state rs_table[NR_PORTS];
  60
  61 struct tty_driver *hp_simserial_driver;
  62
  63 static struct console *console;
  64
  65 extern struct console *console_drivers; /* from kernel/printk.c */
  66
  67 static void receive_chars(struct tty_struct *tty)
  68 {
  69         unsigned char ch;
  70         static unsigned char seen_esc = 0;
  71
  72         while ( (ch = ia64_ssc(0, 0, 0, 0, SSC_GETCHAR)) ) {
  73                 if ( ch == 27 && seen_esc == 0 ) {
  74                         seen_esc = 1;
  75                         continue;
  76                 } else {
  77                         if ( seen_esc==1 && ch == 'O' ) {
  78                                 seen_esc = 2;
  79                                 continue;
  80                         } else if ( seen_esc == 2 ) {
  81                                 if ( ch == 'P' ) /* F1 */
  82                                         show_state();
  83 #ifdef CONFIG_MAGIC_SYSRQ
  84                                 if ( ch == 'S' ) { /* F4 */
  85                                         do
  86                                                 ch = ia64_ssc(0, 0, 0, 0,
  87                                                               SSC_GETCHAR);
  88                                         while (!ch);
  89                                         handle_sysrq(ch);
  90                                 }
  91 #endif
  92                                 seen_esc = 0;
  93                                 continue;
  94                         }
  95                 }
  96                 seen_esc = 0;
  97
  98                 if (tty_insert_flip_char(tty, ch, TTY_NORMAL) == 0)
  99                         break;
 100         }
 101         tty_flip_buffer_push(tty);
 102 }
 103
 104 /*
 105  * This is the serial driver's interrupt routine for a single port
 106  */
 107 static irqreturn_t rs_interrupt_single(int irq, void *dev_id)
 108 {
 109         struct serial_state *info = dev_id;
 110         struct tty_struct *tty = tty_port_tty_get(&info->port);
 111
 112         if (!tty) {
 113                 printk(KERN_INFO "simrs_interrupt_single: info|tty=0 info=%p problem\n", info);
 114                 return IRQ_NONE;
 115         }
 116         /*
 117          * pretty simple in our case, because we only get interrupts
 118          * on inbound traffic
 119          */
 120         receive_chars(tty);
 121         tty_kref_put(tty);
 122         return IRQ_HANDLED;
 123 }
 124
 125 /*
 126  * -------------------------------------------------------------------
 127  * Here ends the serial interrupt routines.
 128  * -------------------------------------------------------------------
 129  */
 130
 131 static int rs_put_char(struct tty_struct *tty, unsigned char ch)
 132 {
 133         struct serial_state *info = tty->driver_data;
 134         unsigned long flags;
 135
 136         if (!tty || !info->xmit.buf)
 137                 return 0;
 138
 139         local_irq_save(flags);
 140         if (CIRC_SPACE(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE) == 0) {
 141                 local_irq_restore(flags);
 142                 return 0;
 143         }
 144         info->xmit.buf[info->xmit.head] = ch;
 145         info->xmit.head = (info->xmit.head + 1) & (SERIAL_XMIT_SIZE-1);
 146         local_irq_restore(flags);
 147         return 1;
 148 }
 149
 150 static void transmit_chars(struct tty_struct *tty, struct serial_state *info,
 151                 int *intr_done)
 152 {
 153         int count;
 154         unsigned long flags;
 155
 156         local_irq_save(flags);
 157
 158         if (info->x_char) {
 159                 char c = info->x_char;
 160
 161                 console->write(console, &c, 1);
 162
 163                 info->x_char = 0;
 164
 165                 goto out;
 166         }
 167
 168         if (info->xmit.head == info->xmit.tail || tty->stopped ||
 169                         tty->hw_stopped) {
 170 #ifdef SIMSERIAL_DEBUG
 171                 printk("transmit_chars: head=%d, tail=%d, stopped=%d\n",
 172                        info->xmit.head, info->xmit.tail, tty->stopped);
 173 #endif
 174                 goto out;
 175         }
 176         /*
 177          * We removed the loop and try to do it in to chunks. We need
 178          * 2 operations maximum because it's a ring buffer.
 179          *
 180          * First from current to tail if possible.
 181          * Then from the beginning of the buffer until necessary
 182          */
 183
 184         count = min(CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE),
 185                     SERIAL_XMIT_SIZE - info->xmit.tail);
 186         console->write(console, info->xmit.buf+info->xmit.tail, count);
 187
 188         info->xmit.tail = (info->xmit.tail+count) & (SERIAL_XMIT_SIZE-1);
 189
 190         /*
 191          * We have more at the beginning of the buffer
 192          */
 193         count = CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
 194         if (count) {
 195                 console->write(console, info->xmit.buf, count);
 196                 info->xmit.tail += count;
 197         }
 198 out:
 199         local_irq_restore(flags);
 200 }
 201
 202 static void rs_flush_chars(struct tty_struct *tty)
 203 {
 204         struct serial_state *info = tty->driver_data;
 205
 206         if (info->xmit.head == info->xmit.tail || tty->stopped || tty->hw_stopped ||
 207             !info->xmit.buf)
 208                 return;
 209
 210         transmit_chars(tty, info, NULL);
 211 }
 212
 213
 214 static int rs_write(struct tty_struct * tty,
 215                     const unsigned char *buf, int count)
 216 {
 217         struct serial_state *info = tty->driver_data;
 218         int     c, ret = 0;
 219         unsigned long flags;
 220
 221         if (!tty || !info->xmit.buf)
 222                 return 0;
 223
 224         local_irq_save(flags);
 225         while (1) {
 226                 c = CIRC_SPACE_TO_END(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
 227                 if (count < c)
 228                         c = count;
 229                 if (c <= 0) {
 230                         break;
 231                 }
 232                 memcpy(info->xmit.buf + info->xmit.head, buf, c);
 233                 info->xmit.head = ((info->xmit.head + c) &
 234                                    (SERIAL_XMIT_SIZE-1));
 235                 buf += c;
 236                 count -= c;
 237                 ret += c;
 238         }
 239         local_irq_restore(flags);
 240         /*
 241          * Hey, we transmit directly from here in our case
 242          */
 243         if (CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE)
 244             && !tty->stopped && !tty->hw_stopped) {
 245                 transmit_chars(tty, info, NULL);
 246         }
 247         return ret;
 248 }
 249
 250 static int rs_write_room(struct tty_struct *tty)
 251 {
 252         struct serial_state *info = tty->driver_data;
 253
 254         return CIRC_SPACE(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
 255 }
 256
 257 static int rs_chars_in_buffer(struct tty_struct *tty)
 258 {
 259         struct serial_state *info = tty->driver_data;
 260
 261         return CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
 262 }
 263
 264 static void rs_flush_buffer(struct tty_struct *tty)
 265 {
 266         struct serial_state *info = tty->driver_data;
 267         unsigned long flags;
 268
 269         local_irq_save(flags);
 270         info->xmit.head = info->xmit.tail = 0;
 271         local_irq_restore(flags);
 272
 273         tty_wakeup(tty);
 274 }
 275
 276 /*
 277  * This function is used to send a high-priority XON/XOFF character to
 278  * the device
 279  */
 280 static void rs_send_xchar(struct tty_struct *tty, char ch)
 281 {
 282         struct serial_state *info = tty->driver_data;
 283
 284         info->x_char = ch;
 285         if (ch) {
 286                 /*
 287                  * I guess we could call console->write() directly but
 288                  * let's do that for now.
 289                  */
 290                 transmit_chars(tty, info, NULL);
 291         }
 292 }
 293
 294 /*
 295  * ------------------------------------------------------------
 296  * rs_throttle()
 297  *
 298  * This routine is called by the upper-layer tty layer to signal that
 299  * incoming characters should be throttled.
 300  * ------------------------------------------------------------
 301  */
 302 static void rs_throttle(struct tty_struct * tty)
 303 {
 304         if (I_IXOFF(tty)) rs_send_xchar(tty, STOP_CHAR(tty));
 305
 306         printk(KERN_INFO "simrs_throttle called\n");
 307 }
 308
 309 static void rs_unthrottle(struct tty_struct * tty)
 310 {
 311         struct serial_state *info = tty->driver_data;
 312
 313         if (I_IXOFF(tty)) {
 314                 if (info->x_char)
 315                         info->x_char = 0;
 316                 else
 317                         rs_send_xchar(tty, START_CHAR(tty));
 318         }
 319         printk(KERN_INFO "simrs_unthrottle called\n");
 320 }
 321
 322
 323 static int rs_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
 324 {
 325         if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
 326             (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGSTRUCT) &&
 327             (cmd != TIOCMIWAIT)) {
 328                 if (tty->flags & (1 << TTY_IO_ERROR))
 329                     return -EIO;
 330         }
 331
 332         switch (cmd) {
 333                 case TIOCGSERIAL:
 334                         printk(KERN_INFO "simrs_ioctl TIOCGSERIAL called\n");
 335                         return 0;
 336                 case TIOCSSERIAL:
 337                         printk(KERN_INFO "simrs_ioctl TIOCSSERIAL called\n");
 338                         return 0;
 339                 case TIOCSERCONFIG:
 340                         printk(KERN_INFO "rs_ioctl: TIOCSERCONFIG called\n");
 341                         return -EINVAL;
 342
 343                 case TIOCSERGETLSR: /* Get line status register */
 344                         printk(KERN_INFO "rs_ioctl: TIOCSERGETLSR called\n");
 345                         return  -EINVAL;
 346
 347                 case TIOCSERGSTRUCT:
 348                         printk(KERN_INFO "rs_ioctl: TIOCSERGSTRUCT called\n");
 349 #if 0
 350                         if (copy_to_user((struct async_struct *) arg,
 351                                          info, sizeof(struct async_struct)))
 352                                 return -EFAULT;
 353 #endif
 354                         return 0;
 355
 356                 /*
 357                  * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
 358                  * - mask passed in arg for lines of interest
 359                  *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
 360                  * Caller should use TIOCGICOUNT to see which one it was
 361                  */
 362                 case TIOCMIWAIT:
 363                         printk(KERN_INFO "rs_ioctl: TIOCMIWAIT: called\n");
 364                         return 0;
 365                 case TIOCSERGWILD:
 366                 case TIOCSERSWILD:
 367                         /* "setserial -W" is called in Debian boot */
 368                         printk (KERN_INFO "TIOCSER?WILD ioctl obsolete, ignored.\n");
 369                         return 0;
 370
 371                 default:
 372                         return -ENOIOCTLCMD;
 373                 }
 374         return 0;
 375 }
 376
 377 #define RELEVANT_IFLAG(iflag) (iflag & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))
 378
 379 static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
 380 {
 381         /* Handle turning off CRTSCTS */
 382         if ((old_termios->c_cflag & CRTSCTS) &&
 383             !(tty->termios->c_cflag & CRTSCTS)) {
 384                 tty->hw_stopped = 0;
 385         }
 386 }
 387 /*
 388  * This routine will shutdown a serial port; interrupts are disabled, and
 389  * DTR is dropped if the hangup on close termio flag is on.
 390  */
 391 static void shutdown(struct tty_port *port)
 392 {
 393         struct serial_state *info = container_of(port, struct serial_state,
 394                         port);
 395         unsigned long flags;
 396
 397         local_irq_save(flags);
 398         {
 399                 if (info->irq)
 400                         free_irq(info->irq, info);
 401
 402                 if (info->xmit.buf) {
 403                         free_page((unsigned long) info->xmit.buf);
 404                         info->xmit.buf = NULL;
 405                 }
 406         }
 407         local_irq_restore(flags);
 408 }
 409
 410 static void rs_close(struct tty_struct *tty, struct file * filp)
 411 {
 412         struct serial_state *info = tty->driver_data;
 413
 414         tty_port_close(&info->port, tty, filp);
 415 }
 416
 417 static void rs_hangup(struct tty_struct *tty)
 418 {
 419         struct serial_state *info = tty->driver_data;
 420
 421         rs_flush_buffer(tty);
 422         tty_port_hangup(&info->port);
 423 }
 424
 425 static int activate(struct tty_port *port, struct tty_struct *tty)
 426 {
 427         struct serial_state *state = container_of(port, struct serial_state,
 428                         port);
 429         unsigned long flags;
 430         int     retval=0;
 431         unsigned long page;
 432
 433         page = get_zeroed_page(GFP_KERNEL);
 434         if (!page)
 435                 return -ENOMEM;
 436
 437         local_irq_save(flags);
 438
 439         if (state->xmit.buf)
 440                 free_page(page);
 441         else
 442                 state->xmit.buf = (unsigned char *) page;
 443
 444         /*
 445          * Allocate the IRQ if necessary
 446          */
 447         if (state->irq) {
 448                 retval = request_irq(state->irq, rs_interrupt_single, 0,
 449                                 "simserial", state);
 450                 if (retval)
 451                         goto errout;
 452         }
 453
 454         state->xmit.head = state->xmit.tail = 0;
 455
 456         /*
 457          * Set up the tty->alt_speed kludge
 458          */
 459         if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
 460                 tty->alt_speed = 57600;
 461         if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
 462                 tty->alt_speed = 115200;
 463         if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
 464                 tty->alt_speed = 230400;
 465         if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
 466                 tty->alt_speed = 460800;
 467
 468 errout:
 469         local_irq_restore(flags);
 470         return retval;
 471 }
 472
 473
 474 /*
 475  * This routine is called whenever a serial port is opened.  It
 476  * enables interrupts for a serial port, linking in its async structure into
 477  * the IRQ chain.   It also performs the serial-specific
 478  * initialization for the tty structure.
 479  */
 480 static int rs_open(struct tty_struct *tty, struct file * filp)
 481 {
 482         struct serial_state *info = rs_table + tty->index;
 483         struct tty_port *port = &info->port;
 484
 485         tty->driver_data = info;
 486         tty->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
 487
 488         /*
 489          * figure out which console to use (should be one already)
 490          */
 491         console = console_drivers;
 492         while (console) {
 493                 if ((console->flags & CON_ENABLED) && console->write) break;
 494                 console = console->next;
 495         }
 496
 497         return tty_port_open(port, tty, filp);
 498 }
 499
 500 /*
 501  * /proc fs routines....
 502  */
 503
 504 static int rs_proc_show(struct seq_file *m, void *v)
 505 {
 506         int i;
 507
 508         seq_printf(m, "simserinfo:1.0 driver:%s\n", serial_version);
 509         for (i = 0; i < NR_PORTS; i++)
 510                 seq_printf(m, "%d: uart:16550 port:3F8 irq:%d\n",
 511                        i, rs_table[i].irq);
 512         return 0;
 513 }
 514
 515 static int rs_proc_open(struct inode *inode, struct file *file)
 516 {
 517         return single_open(file, rs_proc_show, NULL);
 518 }
 519
 520 static const struct file_operations rs_proc_fops = {
 521         .owner          = THIS_MODULE,
 522         .open           = rs_proc_open,
 523         .read           = seq_read,
 524         .llseek         = seq_lseek,
 525         .release        = single_release,
 526 };
 527
 528 /*
 529  * ---------------------------------------------------------------------
 530  * rs_init() and friends
 531  *
 532  * rs_init() is called at boot-time to initialize the serial driver.
 533  * ---------------------------------------------------------------------
 534  */
 535
 536 /*
 537  * This routine prints out the appropriate serial driver version
 538  * number, and identifies which options were configured into this
 539  * driver.
 540  */
 541 static inline void show_serial_version(void)
 542 {
 543         printk(KERN_INFO "%s version %s with", serial_name, serial_version);
 544         printk(KERN_INFO " no serial options enabled\n");
 545 }
 546
 547 static const struct tty_operations hp_ops = {
 548         .open = rs_open,
 549         .close = rs_close,
 550         .write = rs_write,
 551         .put_char = rs_put_char,
 552         .flush_chars = rs_flush_chars,
 553         .write_room = rs_write_room,
 554         .chars_in_buffer = rs_chars_in_buffer,
 555         .flush_buffer = rs_flush_buffer,
 556         .ioctl = rs_ioctl,
 557         .throttle = rs_throttle,
 558         .unthrottle = rs_unthrottle,
 559         .send_xchar = rs_send_xchar,
 560         .set_termios = rs_set_termios,
 561         .hangup = rs_hangup,
 562         .proc_fops = &rs_proc_fops,
 563 };
 564
 565 static const struct tty_port_operations hp_port_ops = {
 566         .activate = activate,
 567         .shutdown = shutdown,
 568 };
 569
 570 /*
 571  * The serial driver boot-time initialization code!
 572  */
 573 static int __init simrs_init(void)
 574 {
 575         struct serial_state *state;
 576         int retval;
 577
 578         if (!ia64_platform_is("hpsim"))
 579                 return -ENODEV;
 580
 581         hp_simserial_driver = alloc_tty_driver(NR_PORTS);
 582         if (!hp_simserial_driver)
 583                 return -ENOMEM;
 584
 585         show_serial_version();
 586
 587         /* Initialize the tty_driver structure */
 588
 589         hp_simserial_driver->driver_name = "simserial";
 590         hp_simserial_driver->name = "ttyS";
 591         hp_simserial_driver->major = TTY_MAJOR;
 592         hp_simserial_driver->minor_start = 64;
 593         hp_simserial_driver->type = TTY_DRIVER_TYPE_SERIAL;
 594         hp_simserial_driver->subtype = SERIAL_TYPE_NORMAL;
 595         hp_simserial_driver->init_termios = tty_std_termios;
 596         hp_simserial_driver->init_termios.c_cflag =
 597                 B9600 | CS8 | CREAD | HUPCL | CLOCAL;
 598         hp_simserial_driver->flags = TTY_DRIVER_REAL_RAW;
 599         tty_set_operations(hp_simserial_driver, &hp_ops);
 600
 601         /*
 602          * Let's have a little bit of fun !
 603          */
 604         state = rs_table;
 605         tty_port_init(&state->port);
 606         state->port.ops = &hp_port_ops;
 607         state->port.close_delay = 0; /* XXX really 0? */
 608
 609         retval = hpsim_get_irq(KEYBOARD_INTR);
 610         if (retval < 0) {
 611                 printk(KERN_ERR "%s: out of interrupt vectors!\n",
 612                                 __func__);
 613                 goto err_free_tty;
 614         }
 615
 616         state->irq = retval;
 617
 618         /* the port is imaginary */
 619         printk(KERN_INFO "ttyS0 at 0x03f8 (irq = %d) is a 16550\n", state->irq);
 620
 621         retval = tty_register_driver(hp_simserial_driver);
 622         if (retval) {
 623                 printk(KERN_ERR "Couldn't register simserial driver\n");
 624                 goto err_free_tty;
 625         }
 626
 627         return 0;
 628 err_free_tty:
 629         put_tty_driver(hp_simserial_driver);
 630         return retval;
 631 }
 632
 633 #ifndef MODULE
 634 __initcall(simrs_init);
 635 #endif