drivers/input/serio/libps2.c

   1 /*
   2  * PS/2 driver library
   3  *
   4  * Copyright (c) 1999-2002 Vojtech Pavlik
   5  * Copyright (c) 2004 Dmitry Torokhov
   6  */
   7
   8 /*
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License version 2 as published by
  11  * the Free Software Foundation.
  12  */
  13
  14 #include <linux/delay.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/input.h>
  19 #include <linux/serio.h>
  20 #include <linux/i8042.h>
  21 #include <linux/libps2.h>
  22
  23 #define DRIVER_DESC     "PS/2 driver library"
  24
  25 MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
  26 MODULE_DESCRIPTION("PS/2 driver library");
  27 MODULE_LICENSE("GPL");
  28
  29 static int ps2_do_sendbyte(struct ps2dev *ps2dev, u8 byte,
  30                            unsigned int timeout, unsigned int max_attempts)
  31         __releases(&ps2dev->serio->lock) __acquires(&ps2dev->serio->lock)
  32 {
  33         int attempt = 0;
  34         int error;
  35
  36         lockdep_assert_held(&ps2dev->serio->lock);
  37
  38         do {
  39                 ps2dev->nak = 1;
  40                 ps2dev->flags |= PS2_FLAG_ACK;
  41
  42                 serio_continue_rx(ps2dev->serio);
  43
  44                 error = serio_write(ps2dev->serio, byte);
  45                 if (error)
  46                         dev_dbg(&ps2dev->serio->dev,
  47                                 "failed to write %#02x: %d\n", byte, error);
  48                 else
  49                         wait_event_timeout(ps2dev->wait,
  50                                            !(ps2dev->flags & PS2_FLAG_ACK),
  51                                            msecs_to_jiffies(timeout));
  52
  53                 serio_pause_rx(ps2dev->serio);
  54         } while (ps2dev->nak == PS2_RET_NAK && ++attempt < max_attempts);
  55
  56         ps2dev->flags &= ~PS2_FLAG_ACK;
  57
  58         if (!error) {
  59                 switch (ps2dev->nak) {
  60                 case 0:
  61                         break;
  62                 case PS2_RET_NAK:
  63                         error = -EAGAIN;
  64                         break;
  65                 case PS2_RET_ERR:
  66                         error = -EPROTO;
  67                         break;
  68                 default:
  69                         error = -EIO;
  70                         break;
  71                 }
  72         }
  73
  74         if (error || attempt > 1)
  75                 dev_dbg(&ps2dev->serio->dev,
  76                         "%02x - %d (%x), attempt %d\n",
  77                         byte, error, ps2dev->nak, attempt);
  78
  79         return error;
  80 }
  81
  82 /*
  83  * ps2_sendbyte() sends a byte to the device and waits for acknowledge.
  84  * It doesn't handle retransmission, the caller is expected to handle
  85  * it when needed.
  86  *
  87  * ps2_sendbyte() can only be called from a process context.
  88  */
  89
  90 int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)
  91 {
  92         int retval;
  93
  94         serio_pause_rx(ps2dev->serio);
  95
  96         retval = ps2_do_sendbyte(ps2dev, byte, timeout, 1);
  97         dev_dbg(&ps2dev->serio->dev, "%02x - %x\n", byte, ps2dev->nak);
  98
  99         serio_continue_rx(ps2dev->serio);
 100
 101         return retval;
 102 }
 103 EXPORT_SYMBOL(ps2_sendbyte);
 104
 105 void ps2_begin_command(struct ps2dev *ps2dev)
 106 {
 107         struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
 108
 109         mutex_lock(m);
 110 }
 111 EXPORT_SYMBOL(ps2_begin_command);
 112
 113 void ps2_end_command(struct ps2dev *ps2dev)
 114 {
 115         struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
 116
 117         mutex_unlock(m);
 118 }
 119 EXPORT_SYMBOL(ps2_end_command);
 120
 121 /*
 122  * ps2_drain() waits for device to transmit requested number of bytes
 123  * and discards them.
 124  */
 125
 126 void ps2_drain(struct ps2dev *ps2dev, size_t maxbytes, unsigned int timeout)
 127 {
 128         if (maxbytes > sizeof(ps2dev->cmdbuf)) {
 129                 WARN_ON(1);
 130                 maxbytes = sizeof(ps2dev->cmdbuf);
 131         }
 132
 133         ps2_begin_command(ps2dev);
 134
 135         serio_pause_rx(ps2dev->serio);
 136         ps2dev->flags = PS2_FLAG_CMD;
 137         ps2dev->cmdcnt = maxbytes;
 138         serio_continue_rx(ps2dev->serio);
 139
 140         wait_event_timeout(ps2dev->wait,
 141                            !(ps2dev->flags & PS2_FLAG_CMD),
 142                            msecs_to_jiffies(timeout));
 143
 144         ps2_end_command(ps2dev);
 145 }
 146 EXPORT_SYMBOL(ps2_drain);
 147
 148 /*
 149  * ps2_is_keyboard_id() checks received ID byte against the list of
 150  * known keyboard IDs.
 151  */
 152
 153 bool ps2_is_keyboard_id(u8 id_byte)
 154 {
 155         static const u8 keyboard_ids[] = {
 156                 0xab,   /* Regular keyboards            */
 157                 0xac,   /* NCD Sun keyboard             */
 158                 0x2b,   /* Trust keyboard, translated   */
 159                 0x5d,   /* Trust keyboard               */
 160                 0x60,   /* NMB SGI keyboard, translated */
 161                 0x47,   /* NMB SGI keyboard             */
 162         };
 163
 164         return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
 165 }
 166 EXPORT_SYMBOL(ps2_is_keyboard_id);
 167
 168 /*
 169  * ps2_adjust_timeout() is called after receiving 1st byte of command
 170  * response and tries to reduce remaining timeout to speed up command
 171  * completion.
 172  */
 173
 174 static int ps2_adjust_timeout(struct ps2dev *ps2dev,
 175                               unsigned int command, unsigned int timeout)
 176 {
 177         switch (command) {
 178         case PS2_CMD_RESET_BAT:
 179                 /*
 180                  * Device has sent the first response byte after
 181                  * reset command, reset is thus done, so we can
 182                  * shorten the timeout.
 183                  * The next byte will come soon (keyboard) or not
 184                  * at all (mouse).
 185                  */
 186                 if (timeout > msecs_to_jiffies(100))
 187                         timeout = msecs_to_jiffies(100);
 188                 break;
 189
 190         case PS2_CMD_GETID:
 191                 /*
 192                  * Microsoft Natural Elite keyboard responds to
 193                  * the GET ID command as it were a mouse, with
 194                  * a single byte. Fail the command so atkbd will
 195                  * use alternative probe to detect it.
 196                  */
 197                 if (ps2dev->cmdbuf[1] == 0xaa) {
 198                         serio_pause_rx(ps2dev->serio);
 199                         ps2dev->flags = 0;
 200                         serio_continue_rx(ps2dev->serio);
 201                         timeout = 0;
 202                 }
 203
 204                 /*
 205                  * If device behind the port is not a keyboard there
 206                  * won't be 2nd byte of ID response.
 207                  */
 208                 if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
 209                         serio_pause_rx(ps2dev->serio);
 210                         ps2dev->flags = ps2dev->cmdcnt = 0;
 211                         serio_continue_rx(ps2dev->serio);
 212                         timeout = 0;
 213                 }
 214                 break;
 215
 216         default:
 217                 break;
 218         }
 219
 220         return timeout;
 221 }
 222
 223 /*
 224  * ps2_command() sends a command and its parameters to the mouse,
 225  * then waits for the response and puts it in the param array.
 226  *
 227  * ps2_command() can only be called from a process context
 228  */
 229
 230 int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
 231 {
 232         unsigned int timeout;
 233         unsigned int send = (command >> 12) & 0xf;
 234         unsigned int receive = (command >> 8) & 0xf;
 235         int rc;
 236         int i;
 237         u8 send_param[16];
 238
 239         if (receive > sizeof(ps2dev->cmdbuf)) {
 240                 WARN_ON(1);
 241                 return -EINVAL;
 242         }
 243
 244         if (send && !param) {
 245                 WARN_ON(1);
 246                 return -EINVAL;
 247         }
 248
 249         memcpy(send_param, param, send);
 250
 251         serio_pause_rx(ps2dev->serio);
 252
 253         ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
 254         ps2dev->cmdcnt = receive;
 255         if (receive && param)
 256                 for (i = 0; i < receive; i++)
 257                         ps2dev->cmdbuf[(receive - 1) - i] = param[i];
 258
 259         /* Signal that we are sending the command byte */
 260         ps2dev->flags |= PS2_FLAG_ACK_CMD;
 261
 262         /*
 263          * Some devices (Synaptics) peform the reset before
 264          * ACKing the reset command, and so it can take a long
 265          * time before the ACK arrives.
 266          */
 267         timeout = command == PS2_CMD_RESET_BAT ? 1000 : 200;
 268
 269         rc = ps2_do_sendbyte(ps2dev, command & 0xff, timeout, 2);
 270         if (rc)
 271                 goto out_reset_flags;
 272
 273         /* Now we are sending command parameters, if any */
 274         ps2dev->flags &= ~PS2_FLAG_ACK_CMD;
 275
 276         for (i = 0; i < send; i++) {
 277                 rc = ps2_do_sendbyte(ps2dev, param[i], 200, 2);
 278                 if (rc)
 279                         goto out_reset_flags;
 280         }
 281
 282         serio_continue_rx(ps2dev->serio);
 283
 284         /*
 285          * The reset command takes a long time to execute.
 286          */
 287         timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
 288
 289         timeout = wait_event_timeout(ps2dev->wait,
 290                                      !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
 291
 292         if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
 293
 294                 timeout = ps2_adjust_timeout(ps2dev, command, timeout);
 295                 wait_event_timeout(ps2dev->wait,
 296                                    !(ps2dev->flags & PS2_FLAG_CMD), timeout);
 297         }
 298
 299         serio_pause_rx(ps2dev->serio);
 300
 301         if (param)
 302                 for (i = 0; i < receive; i++)
 303                         param[i] = ps2dev->cmdbuf[(receive - 1) - i];
 304
 305         if (ps2dev->cmdcnt &&
 306             (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1)) {
 307                 rc = -EPROTO;
 308                 goto out_reset_flags;
 309         }
 310
 311         rc = 0;
 312
 313  out_reset_flags:
 314         ps2dev->flags = 0;
 315         serio_continue_rx(ps2dev->serio);
 316
 317         dev_dbg(&ps2dev->serio->dev,
 318                 "%02x [%*ph] - %x/%08lx [%*ph]\n",
 319                 command & 0xff, send, send_param,
 320                 ps2dev->nak, ps2dev->flags,
 321                 receive, param ?: send_param);
 322
 323         /*
 324          * ps_command() handles resends itself, so do not leak -EAGAIN
 325          * to the callers.
 326          */
 327         return rc != -EAGAIN ? rc : -EPROTO;
 328 }
 329 EXPORT_SYMBOL(__ps2_command);
 330
 331 int ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
 332 {
 333         int rc;
 334
 335         ps2_begin_command(ps2dev);
 336         rc = __ps2_command(ps2dev, param, command);
 337         ps2_end_command(ps2dev);
 338
 339         return rc;
 340 }
 341 EXPORT_SYMBOL(ps2_command);
 342
 343 /*
 344  * ps2_sliced_command() sends an extended PS/2 command to the mouse
 345  * using sliced syntax, understood by advanced devices, such as Logitech
 346  * or Synaptics touchpads. The command is encoded as:
 347  * 0xE6 0xE8 rr 0xE8 ss 0xE8 tt 0xE8 uu where (rr*64)+(ss*16)+(tt*4)+uu
 348  * is the command.
 349  */
 350
 351 int ps2_sliced_command(struct ps2dev *ps2dev, u8 command)
 352 {
 353         int i;
 354         int retval;
 355
 356         ps2_begin_command(ps2dev);
 357
 358         retval = __ps2_command(ps2dev, NULL, PS2_CMD_SETSCALE11);
 359         if (retval)
 360                 goto out;
 361
 362         for (i = 6; i >= 0; i -= 2) {
 363                 u8 d = (command >> i) & 3;
 364                 retval = __ps2_command(ps2dev, &d, PS2_CMD_SETRES);
 365                 if (retval)
 366                         break;
 367         }
 368
 369 out:
 370         dev_dbg(&ps2dev->serio->dev, "%02x - %d\n", command, retval);
 371         ps2_end_command(ps2dev);
 372         return retval;
 373 }
 374 EXPORT_SYMBOL(ps2_sliced_command);
 375
 376 /*
 377  * ps2_init() initializes ps2dev structure
 378  */
 379
 380 void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
 381 {
 382         mutex_init(&ps2dev->cmd_mutex);
 383         lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
 384         init_waitqueue_head(&ps2dev->wait);
 385         ps2dev->serio = serio;
 386 }
 387 EXPORT_SYMBOL(ps2_init);
 388
 389 /*
 390  * ps2_handle_ack() is supposed to be used in interrupt handler
 391  * to properly process ACK/NAK of a command from a PS/2 device.
 392  */
 393
 394 bool ps2_handle_ack(struct ps2dev *ps2dev, u8 data)
 395 {
 396         switch (data) {
 397         case PS2_RET_ACK:
 398                 ps2dev->nak = 0;
 399                 break;
 400
 401         case PS2_RET_NAK:
 402                 ps2dev->flags |= PS2_FLAG_NAK;
 403                 ps2dev->nak = PS2_RET_NAK;
 404                 break;
 405
 406         case PS2_RET_ERR:
 407                 if (ps2dev->flags & PS2_FLAG_NAK) {
 408                         ps2dev->flags &= ~PS2_FLAG_NAK;
 409                         ps2dev->nak = PS2_RET_ERR;
 410                         break;
 411                 }
 412
 413         /*
 414          * Workaround for mice which don't ACK the Get ID command.
 415          * These are valid mouse IDs that we recognize.
 416          */
 417         case 0x00:
 418         case 0x03:
 419         case 0x04:
 420                 if (ps2dev->flags & PS2_FLAG_WAITID) {
 421                         ps2dev->nak = 0;
 422                         break;
 423                 }
 424                 /* Fall through */
 425         default:
 426                 /*
 427                  * Do not signal errors if we get unexpected reply while
 428                  * waiting for an ACK to the initial (first) command byte:
 429                  * the device might not be quiesced yet and continue
 430                  * delivering data.
 431                  * Note that we reset PS2_FLAG_WAITID flag, so the workaround
 432                  * for mice not acknowledging the Get ID command only triggers
 433                  * on the 1st byte; if device spews data we really want to see
 434                  * a real ACK from it.
 435                  */
 436                 dev_dbg(&ps2dev->serio->dev, "unexpected %#02x\n", data);
 437                 ps2dev->flags &= ~PS2_FLAG_WAITID;
 438                 return ps2dev->flags & PS2_FLAG_ACK_CMD;
 439         }
 440
 441         if (!ps2dev->nak) {
 442                 ps2dev->flags &= ~PS2_FLAG_NAK;
 443                 if (ps2dev->cmdcnt)
 444                         ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
 445         }
 446
 447         ps2dev->flags &= ~PS2_FLAG_ACK;
 448         wake_up(&ps2dev->wait);
 449
 450         if (data != PS2_RET_ACK)
 451                 ps2_handle_response(ps2dev, data);
 452
 453         return true;
 454 }
 455 EXPORT_SYMBOL(ps2_handle_ack);
 456
 457 /*
 458  * ps2_handle_response() is supposed to be used in interrupt handler
 459  * to properly store device's response to a command and notify process
 460  * waiting for completion of the command.
 461  */
 462
 463 bool ps2_handle_response(struct ps2dev *ps2dev, u8 data)
 464 {
 465         if (ps2dev->cmdcnt)
 466                 ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
 467
 468         if (ps2dev->flags & PS2_FLAG_CMD1) {
 469                 ps2dev->flags &= ~PS2_FLAG_CMD1;
 470                 if (ps2dev->cmdcnt)
 471                         wake_up(&ps2dev->wait);
 472         }
 473
 474         if (!ps2dev->cmdcnt) {
 475                 ps2dev->flags &= ~PS2_FLAG_CMD;
 476                 wake_up(&ps2dev->wait);
 477         }
 478
 479         return true;
 480 }
 481 EXPORT_SYMBOL(ps2_handle_response);
 482
 483 void ps2_cmd_aborted(struct ps2dev *ps2dev)
 484 {
 485         if (ps2dev->flags & PS2_FLAG_ACK)
 486                 ps2dev->nak = 1;
 487
 488         if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
 489                 wake_up(&ps2dev->wait);
 490
 491         /* reset all flags except last nack */
 492         ps2dev->flags &= PS2_FLAG_NAK;
 493 }
 494 EXPORT_SYMBOL(ps2_cmd_aborted);