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