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/slab.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         mutex_lock(&ps2dev->cmd_mutex);
  61
  62         if (i8042_check_port_owner(ps2dev->serio))
  63                 i8042_lock_chip();
  64 }
  65 EXPORT_SYMBOL(ps2_begin_command);
  66
  67 void ps2_end_command(struct ps2dev *ps2dev)
  68 {
  69         if (i8042_check_port_owner(ps2dev->serio))
  70                 i8042_unlock_chip();
  71
  72         mutex_unlock(&ps2dev->cmd_mutex);
  73 }
  74 EXPORT_SYMBOL(ps2_end_command);
  75
  76 /*
  77  * ps2_drain() waits for device to transmit requested number of bytes
  78  * and discards them.
  79  */
  80
  81 void ps2_drain(struct ps2dev *ps2dev, int maxbytes, int timeout)
  82 {
  83         if (maxbytes > sizeof(ps2dev->cmdbuf)) {
  84                 WARN_ON(1);
  85                 maxbytes = sizeof(ps2dev->cmdbuf);
  86         }
  87
  88         ps2_begin_command(ps2dev);
  89
  90         serio_pause_rx(ps2dev->serio);
  91         ps2dev->flags = PS2_FLAG_CMD;
  92         ps2dev->cmdcnt = maxbytes;
  93         serio_continue_rx(ps2dev->serio);
  94
  95         wait_event_timeout(ps2dev->wait,
  96                            !(ps2dev->flags & PS2_FLAG_CMD),
  97                            msecs_to_jiffies(timeout));
  98
  99         ps2_end_command(ps2dev);
 100 }
 101 EXPORT_SYMBOL(ps2_drain);
 102
 103 /*
 104  * ps2_is_keyboard_id() checks received ID byte against the list of
 105  * known keyboard IDs.
 106  */
 107
 108 int ps2_is_keyboard_id(char id_byte)
 109 {
 110         static const char keyboard_ids[] = {
 111                 0xab,   /* Regular keyboards            */
 112                 0xac,   /* NCD Sun keyboard             */
 113                 0x2b,   /* Trust keyboard, translated   */
 114                 0x5d,   /* Trust keyboard               */
 115                 0x60,   /* NMB SGI keyboard, translated */
 116                 0x47,   /* NMB SGI keyboard             */
 117         };
 118
 119         return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
 120 }
 121 EXPORT_SYMBOL(ps2_is_keyboard_id);
 122
 123 /*
 124  * ps2_adjust_timeout() is called after receiving 1st byte of command
 125  * response and tries to reduce remaining timeout to speed up command
 126  * completion.
 127  */
 128
 129 static int ps2_adjust_timeout(struct ps2dev *ps2dev, int command, int timeout)
 130 {
 131         switch (command) {
 132                 case PS2_CMD_RESET_BAT:
 133                         /*
 134                          * Device has sent the first response byte after
 135                          * reset command, reset is thus done, so we can
 136                          * shorten the timeout.
 137                          * The next byte will come soon (keyboard) or not
 138                          * at all (mouse).
 139                          */
 140                         if (timeout > msecs_to_jiffies(100))
 141                                 timeout = msecs_to_jiffies(100);
 142                         break;
 143
 144                 case PS2_CMD_GETID:
 145                         /*
 146                          * Microsoft Natural Elite keyboard responds to
 147                          * the GET ID command as it were a mouse, with
 148                          * a single byte. Fail the command so atkbd will
 149                          * use alternative probe to detect it.
 150                          */
 151                         if (ps2dev->cmdbuf[1] == 0xaa) {
 152                                 serio_pause_rx(ps2dev->serio);
 153                                 ps2dev->flags = 0;
 154                                 serio_continue_rx(ps2dev->serio);
 155                                 timeout = 0;
 156                         }
 157
 158                         /*
 159                          * If device behind the port is not a keyboard there
 160                          * won't be 2nd byte of ID response.
 161                          */
 162                         if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
 163                                 serio_pause_rx(ps2dev->serio);
 164                                 ps2dev->flags = ps2dev->cmdcnt = 0;
 165                                 serio_continue_rx(ps2dev->serio);
 166                                 timeout = 0;
 167                         }
 168                         break;
 169
 170                 default:
 171                         break;
 172         }
 173
 174         return timeout;
 175 }
 176
 177 /*
 178  * ps2_command() sends a command and its parameters to the mouse,
 179  * then waits for the response and puts it in the param array.
 180  *
 181  * ps2_command() can only be called from a process context
 182  */
 183
 184 int __ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 185 {
 186         int timeout;
 187         int send = (command >> 12) & 0xf;
 188         int receive = (command >> 8) & 0xf;
 189         int rc = -1;
 190         int i;
 191
 192         if (receive > sizeof(ps2dev->cmdbuf)) {
 193                 WARN_ON(1);
 194                 return -1;
 195         }
 196
 197         if (send && !param) {
 198                 WARN_ON(1);
 199                 return -1;
 200         }
 201
 202         serio_pause_rx(ps2dev->serio);
 203         ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
 204         ps2dev->cmdcnt = receive;
 205         if (receive && param)
 206                 for (i = 0; i < receive; i++)
 207                         ps2dev->cmdbuf[(receive - 1) - i] = param[i];
 208         serio_continue_rx(ps2dev->serio);
 209
 210         /*
 211          * Some devices (Synaptics) peform the reset before
 212          * ACKing the reset command, and so it can take a long
 213          * time before the ACK arrrives.
 214          */
 215         if (ps2_sendbyte(ps2dev, command & 0xff,
 216                          command == PS2_CMD_RESET_BAT ? 1000 : 200))
 217                 goto out;
 218
 219         for (i = 0; i < send; i++)
 220                 if (ps2_sendbyte(ps2dev, param[i], 200))
 221                         goto out;
 222
 223         /*
 224          * The reset command takes a long time to execute.
 225          */
 226         timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
 227
 228         timeout = wait_event_timeout(ps2dev->wait,
 229                                      !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
 230
 231         if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
 232
 233                 timeout = ps2_adjust_timeout(ps2dev, command, timeout);
 234                 wait_event_timeout(ps2dev->wait,
 235                                    !(ps2dev->flags & PS2_FLAG_CMD), timeout);
 236         }
 237
 238         if (param)
 239                 for (i = 0; i < receive; i++)
 240                         param[i] = ps2dev->cmdbuf[(receive - 1) - i];
 241
 242         if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
 243                 goto out;
 244
 245         rc = 0;
 246
 247  out:
 248         serio_pause_rx(ps2dev->serio);
 249         ps2dev->flags = 0;
 250         serio_continue_rx(ps2dev->serio);
 251
 252         return rc;
 253 }
 254 EXPORT_SYMBOL(__ps2_command);
 255
 256 int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 257 {
 258         int rc;
 259
 260         ps2_begin_command(ps2dev);
 261         rc = __ps2_command(ps2dev, param, command);
 262         ps2_end_command(ps2dev);
 263
 264         return rc;
 265 }
 266 EXPORT_SYMBOL(ps2_command);
 267
 268 /*
 269  * ps2_init() initializes ps2dev structure
 270  */
 271
 272 void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
 273 {
 274         mutex_init(&ps2dev->cmd_mutex);
 275         lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
 276         init_waitqueue_head(&ps2dev->wait);
 277         ps2dev->serio = serio;
 278 }
 279 EXPORT_SYMBOL(ps2_init);
 280
 281 /*
 282  * ps2_handle_ack() is supposed to be used in interrupt handler
 283  * to properly process ACK/NAK of a command from a PS/2 device.
 284  */
 285
 286 int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
 287 {
 288         switch (data) {
 289                 case PS2_RET_ACK:
 290                         ps2dev->nak = 0;
 291                         break;
 292
 293                 case PS2_RET_NAK:
 294                         ps2dev->flags |= PS2_FLAG_NAK;
 295                         ps2dev->nak = PS2_RET_NAK;
 296                         break;
 297
 298                 case PS2_RET_ERR:
 299                         if (ps2dev->flags & PS2_FLAG_NAK) {
 300                                 ps2dev->flags &= ~PS2_FLAG_NAK;
 301                                 ps2dev->nak = PS2_RET_ERR;
 302                                 break;
 303                         }
 304
 305                 /*
 306                  * Workaround for mice which don't ACK the Get ID command.
 307                  * These are valid mouse IDs that we recognize.
 308                  */
 309                 case 0x00:
 310                 case 0x03:
 311                 case 0x04:
 312                         if (ps2dev->flags & PS2_FLAG_WAITID) {
 313                                 ps2dev->nak = 0;
 314                                 break;
 315                         }
 316                         /* Fall through */
 317                 default:
 318                         return 0;
 319         }
 320
 321
 322         if (!ps2dev->nak) {
 323                 ps2dev->flags &= ~PS2_FLAG_NAK;
 324                 if (ps2dev->cmdcnt)
 325                         ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
 326         }
 327
 328         ps2dev->flags &= ~PS2_FLAG_ACK;
 329         wake_up(&ps2dev->wait);
 330
 331         if (data != PS2_RET_ACK)
 332                 ps2_handle_response(ps2dev, data);
 333
 334         return 1;
 335 }
 336 EXPORT_SYMBOL(ps2_handle_ack);
 337
 338 /*
 339  * ps2_handle_response() is supposed to be used in interrupt handler
 340  * to properly store device's response to a command and notify process
 341  * waiting for completion of the command.
 342  */
 343
 344 int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data)
 345 {
 346         if (ps2dev->cmdcnt)
 347                 ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
 348
 349         if (ps2dev->flags & PS2_FLAG_CMD1) {
 350                 ps2dev->flags &= ~PS2_FLAG_CMD1;
 351                 if (ps2dev->cmdcnt)
 352                         wake_up(&ps2dev->wait);
 353         }
 354
 355         if (!ps2dev->cmdcnt) {
 356                 ps2dev->flags &= ~PS2_FLAG_CMD;
 357                 wake_up(&ps2dev->wait);
 358         }
 359
 360         return 1;
 361 }
 362 EXPORT_SYMBOL(ps2_handle_response);
 363
 364 void ps2_cmd_aborted(struct ps2dev *ps2dev)
 365 {
 366         if (ps2dev->flags & PS2_FLAG_ACK)
 367                 ps2dev->nak = 1;
 368
 369         if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
 370                 wake_up(&ps2dev->wait);
 371
 372         /* reset all flags except last nack */
 373         ps2dev->flags &= PS2_FLAG_NAK;
 374 }
 375 EXPORT_SYMBOL(ps2_cmd_aborted);