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