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