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/init.h>
  22 #include <linux/libps2.h>
  23
  24 #define DRIVER_DESC     "PS/2 driver library"
  25
  26 MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
  27 MODULE_DESCRIPTION("PS/2 driver library");
  28 MODULE_LICENSE("GPL");
  29
  30 /*
  31  * ps2_sendbyte() sends a byte to the device and waits for acknowledge.
  32  * It doesn't handle retransmission, though it could - because if there
  33  * is a need for retransmissions device has to be replaced anyway.
  34  *
  35  * ps2_sendbyte() can only be called from a process context.
  36  */
  37
  38 int ps2_sendbyte(struct ps2dev *ps2dev, unsigned char byte, int timeout)
  39 {
  40         serio_pause_rx(ps2dev->serio);
  41         ps2dev->nak = 1;
  42         ps2dev->flags |= PS2_FLAG_ACK;
  43         serio_continue_rx(ps2dev->serio);
  44
  45         if (serio_write(ps2dev->serio, byte) == 0)
  46                 wait_event_timeout(ps2dev->wait,
  47                                    !(ps2dev->flags & PS2_FLAG_ACK),
  48                                    msecs_to_jiffies(timeout));
  49
  50         serio_pause_rx(ps2dev->serio);
  51         ps2dev->flags &= ~PS2_FLAG_ACK;
  52         serio_continue_rx(ps2dev->serio);
  53
  54         return -ps2dev->nak;
  55 }
  56 EXPORT_SYMBOL(ps2_sendbyte);
  57
  58 void ps2_begin_command(struct ps2dev *ps2dev)
  59 {
  60         struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
  61
  62         mutex_lock(m);
  63 }
  64 EXPORT_SYMBOL(ps2_begin_command);
  65
  66 void ps2_end_command(struct ps2dev *ps2dev)
  67 {
  68         struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
  69
  70         mutex_unlock(m);
  71 }
  72 EXPORT_SYMBOL(ps2_end_command);
  73
  74 /*
  75  * ps2_drain() waits for device to transmit requested number of bytes
  76  * and discards them.
  77  */
  78
  79 void ps2_drain(struct ps2dev *ps2dev, int maxbytes, int timeout)
  80 {
  81         if (maxbytes > sizeof(ps2dev->cmdbuf)) {
  82                 WARN_ON(1);
  83                 maxbytes = sizeof(ps2dev->cmdbuf);
  84         }
  85
  86         ps2_begin_command(ps2dev);
  87
  88         serio_pause_rx(ps2dev->serio);
  89         ps2dev->flags = PS2_FLAG_CMD;
  90         ps2dev->cmdcnt = maxbytes;
  91         serio_continue_rx(ps2dev->serio);
  92
  93         wait_event_timeout(ps2dev->wait,
  94                            !(ps2dev->flags & PS2_FLAG_CMD),
  95                            msecs_to_jiffies(timeout));
  96
  97         ps2_end_command(ps2dev);
  98 }
  99 EXPORT_SYMBOL(ps2_drain);
 100
 101 /*
 102  * ps2_is_keyboard_id() checks received ID byte against the list of
 103  * known keyboard IDs.
 104  */
 105
 106 int ps2_is_keyboard_id(char id_byte)
 107 {
 108         static const char keyboard_ids[] = {
 109                 0xab,   /* Regular keyboards            */
 110                 0xac,   /* NCD Sun keyboard             */
 111                 0x2b,   /* Trust keyboard, translated   */
 112                 0x5d,   /* Trust keyboard               */
 113                 0x60,   /* NMB SGI keyboard, translated */
 114                 0x47,   /* NMB SGI keyboard             */
 115         };
 116
 117         return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
 118 }
 119 EXPORT_SYMBOL(ps2_is_keyboard_id);
 120
 121 /*
 122  * ps2_adjust_timeout() is called after receiving 1st byte of command
 123  * response and tries to reduce remaining timeout to speed up command
 124  * completion.
 125  */
 126
 127 static int ps2_adjust_timeout(struct ps2dev *ps2dev, int command, int timeout)
 128 {
 129         switch (command) {
 130                 case PS2_CMD_RESET_BAT:
 131                         /*
 132                          * Device has sent the first response byte after
 133                          * reset command, reset is thus done, so we can
 134                          * shorten the timeout.
 135                          * The next byte will come soon (keyboard) or not
 136                          * at all (mouse).
 137                          */
 138                         if (timeout > msecs_to_jiffies(100))
 139                                 timeout = msecs_to_jiffies(100);
 140                         break;
 141
 142                 case PS2_CMD_GETID:
 143                         /*
 144                          * Microsoft Natural Elite keyboard responds to
 145                          * the GET ID command as it were a mouse, with
 146                          * a single byte. Fail the command so atkbd will
 147                          * use alternative probe to detect it.
 148                          */
 149                         if (ps2dev->cmdbuf[1] == 0xaa) {
 150                                 serio_pause_rx(ps2dev->serio);
 151                                 ps2dev->flags = 0;
 152                                 serio_continue_rx(ps2dev->serio);
 153                                 timeout = 0;
 154                         }
 155
 156                         /*
 157                          * If device behind the port is not a keyboard there
 158                          * won't be 2nd byte of ID response.
 159                          */
 160                         if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
 161                                 serio_pause_rx(ps2dev->serio);
 162                                 ps2dev->flags = ps2dev->cmdcnt = 0;
 163                                 serio_continue_rx(ps2dev->serio);
 164                                 timeout = 0;
 165                         }
 166                         break;
 167
 168                 default:
 169                         break;
 170         }
 171
 172         return timeout;
 173 }
 174
 175 /*
 176  * ps2_command() sends a command and its parameters to the mouse,
 177  * then waits for the response and puts it in the param array.
 178  *
 179  * ps2_command() can only be called from a process context
 180  */
 181
 182 int __ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 183 {
 184         int timeout;
 185         int send = (command >> 12) & 0xf;
 186         int receive = (command >> 8) & 0xf;
 187         int rc = -1;
 188         int i;
 189
 190         if (receive > sizeof(ps2dev->cmdbuf)) {
 191                 WARN_ON(1);
 192                 return -1;
 193         }
 194
 195         if (send && !param) {
 196                 WARN_ON(1);
 197                 return -1;
 198         }
 199
 200         serio_pause_rx(ps2dev->serio);
 201         ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
 202         ps2dev->cmdcnt = receive;
 203         if (receive && param)
 204                 for (i = 0; i < receive; i++)
 205                         ps2dev->cmdbuf[(receive - 1) - i] = param[i];
 206         serio_continue_rx(ps2dev->serio);
 207
 208         /*
 209          * Some devices (Synaptics) peform the reset before
 210          * ACKing the reset command, and so it can take a long
 211          * time before the ACK arrives.
 212          */
 213         if (ps2_sendbyte(ps2dev, command & 0xff,
 214                          command == PS2_CMD_RESET_BAT ? 1000 : 200))
 215                 goto out;
 216
 217         for (i = 0; i < send; i++)
 218                 if (ps2_sendbyte(ps2dev, param[i], 200))
 219                         goto out;
 220
 221         /*
 222          * The reset command takes a long time to execute.
 223          */
 224         timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
 225
 226         timeout = wait_event_timeout(ps2dev->wait,
 227                                      !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
 228
 229         if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
 230
 231                 timeout = ps2_adjust_timeout(ps2dev, command, timeout);
 232                 wait_event_timeout(ps2dev->wait,
 233                                    !(ps2dev->flags & PS2_FLAG_CMD), timeout);
 234         }
 235
 236         if (param)
 237                 for (i = 0; i < receive; i++)
 238                         param[i] = ps2dev->cmdbuf[(receive - 1) - i];
 239
 240         if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
 241                 goto out;
 242
 243         rc = 0;
 244
 245  out:
 246         serio_pause_rx(ps2dev->serio);
 247         ps2dev->flags = 0;
 248         serio_continue_rx(ps2dev->serio);
 249
 250         return rc;
 251 }
 252 EXPORT_SYMBOL(__ps2_command);
 253
 254 int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 255 {
 256         int rc;
 257
 258         ps2_begin_command(ps2dev);
 259         rc = __ps2_command(ps2dev, param, command);
 260         ps2_end_command(ps2dev);
 261
 262         return rc;
 263 }
 264 EXPORT_SYMBOL(ps2_command);
 265
 266 /*
 267  * ps2_init() initializes ps2dev structure
 268  */
 269
 270 void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
 271 {
 272         mutex_init(&ps2dev->cmd_mutex);
 273         lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
 274         init_waitqueue_head(&ps2dev->wait);
 275         ps2dev->serio = serio;
 276 }
 277 EXPORT_SYMBOL(ps2_init);
 278
 279 /*
 280  * ps2_handle_ack() is supposed to be used in interrupt handler
 281  * to properly process ACK/NAK of a command from a PS/2 device.
 282  */
 283
 284 int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
 285 {
 286         switch (data) {
 287                 case PS2_RET_ACK:
 288                         ps2dev->nak = 0;
 289                         break;
 290
 291                 case PS2_RET_NAK:
 292                         ps2dev->flags |= PS2_FLAG_NAK;
 293                         ps2dev->nak = PS2_RET_NAK;
 294                         break;
 295
 296                 case PS2_RET_ERR:
 297                         if (ps2dev->flags & PS2_FLAG_NAK) {
 298                                 ps2dev->flags &= ~PS2_FLAG_NAK;
 299                                 ps2dev->nak = PS2_RET_ERR;
 300                                 break;
 301                         }
 302
 303                 /*
 304                  * Workaround for mice which don't ACK the Get ID command.
 305                  * These are valid mouse IDs that we recognize.
 306                  */
 307                 case 0x00:
 308                 case 0x03:
 309                 case 0x04:
 310                         if (ps2dev->flags & PS2_FLAG_WAITID) {
 311                                 ps2dev->nak = 0;
 312                                 break;
 313                         }
 314                         /* Fall through */
 315                 default:
 316                         return 0;
 317         }
 318
 319
 320         if (!ps2dev->nak) {
 321                 ps2dev->flags &= ~PS2_FLAG_NAK;
 322                 if (ps2dev->cmdcnt)
 323                         ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
 324         }
 325
 326         ps2dev->flags &= ~PS2_FLAG_ACK;
 327         wake_up(&ps2dev->wait);
 328
 329         if (data != PS2_RET_ACK)
 330                 ps2_handle_response(ps2dev, data);
 331
 332         return 1;
 333 }
 334 EXPORT_SYMBOL(ps2_handle_ack);
 335
 336 /*
 337  * ps2_handle_response() is supposed to be used in interrupt handler
 338  * to properly store device's response to a command and notify process
 339  * waiting for completion of the command.
 340  */
 341
 342 int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data)
 343 {
 344         if (ps2dev->cmdcnt)
 345                 ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
 346
 347         if (ps2dev->flags & PS2_FLAG_CMD1) {
 348                 ps2dev->flags &= ~PS2_FLAG_CMD1;
 349                 if (ps2dev->cmdcnt)
 350                         wake_up(&ps2dev->wait);
 351         }
 352
 353         if (!ps2dev->cmdcnt) {
 354                 ps2dev->flags &= ~PS2_FLAG_CMD;
 355                 wake_up(&ps2dev->wait);
 356         }
 357
 358         return 1;
 359 }
 360 EXPORT_SYMBOL(ps2_handle_response);
 361
 362 void ps2_cmd_aborted(struct ps2dev *ps2dev)
 363 {
 364         if (ps2dev->flags & PS2_FLAG_ACK)
 365                 ps2dev->nak = 1;
 366
 367         if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
 368                 wake_up(&ps2dev->wait);
 369
 370         /* reset all flags except last nack */
 371         ps2dev->flags &= PS2_FLAG_NAK;
 372 }
 373 EXPORT_SYMBOL(ps2_cmd_aborted);