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 /*
  30  * ps2_sendbyte() sends a byte to the device and waits for acknowledge.
  31  * It doesn't handle retransmission, though it could - because if there
  32  * is a need for retransmissions device has to be replaced anyway.
  33  *
  34  * ps2_sendbyte() can only be called from a process context.
  35  */
  36
  37 int ps2_sendbyte(struct ps2dev *ps2dev, unsigned char byte, int timeout)
  38 {
  39         serio_pause_rx(ps2dev->serio);
  40         ps2dev->nak = 1;
  41         ps2dev->flags |= PS2_FLAG_ACK;
  42         serio_continue_rx(ps2dev->serio);
  43
  44         if (serio_write(ps2dev->serio, byte) == 0)
  45                 wait_event_timeout(ps2dev->wait,
  46                                    !(ps2dev->flags & PS2_FLAG_ACK),
  47                                    msecs_to_jiffies(timeout));
  48
  49         serio_pause_rx(ps2dev->serio);
  50         ps2dev->flags &= ~PS2_FLAG_ACK;
  51         serio_continue_rx(ps2dev->serio);
  52
  53         return -ps2dev->nak;
  54 }
  55 EXPORT_SYMBOL(ps2_sendbyte);
  56
  57 void ps2_begin_command(struct ps2dev *ps2dev)
  58 {
  59         mutex_lock(&ps2dev->cmd_mutex);
  60
  61         if (i8042_check_port_owner(ps2dev->serio))
  62                 i8042_lock_chip();
  63 }
  64 EXPORT_SYMBOL(ps2_begin_command);
  65
  66 void ps2_end_command(struct ps2dev *ps2dev)
  67 {
  68         if (i8042_check_port_owner(ps2dev->serio))
  69                 i8042_unlock_chip();
  70
  71         mutex_unlock(&ps2dev->cmd_mutex);
  72 }
  73 EXPORT_SYMBOL(ps2_end_command);
  74
  75 /*
  76  * ps2_drain() waits for device to transmit requested number of bytes
  77  * and discards them.
  78  */
  79
  80 void ps2_drain(struct ps2dev *ps2dev, int maxbytes, int timeout)
  81 {
  82         if (maxbytes > sizeof(ps2dev->cmdbuf)) {
  83                 WARN_ON(1);
  84                 maxbytes = sizeof(ps2dev->cmdbuf);
  85         }
  86
  87         ps2_begin_command(ps2dev);
  88
  89         serio_pause_rx(ps2dev->serio);
  90         ps2dev->flags = PS2_FLAG_CMD;
  91         ps2dev->cmdcnt = maxbytes;
  92         serio_continue_rx(ps2dev->serio);
  93
  94         wait_event_timeout(ps2dev->wait,
  95                            !(ps2dev->flags & PS2_FLAG_CMD),
  96                            msecs_to_jiffies(timeout));
  97
  98         ps2_end_command(ps2dev);
  99 }
 100 EXPORT_SYMBOL(ps2_drain);
 101
 102 /*
 103  * ps2_is_keyboard_id() checks received ID byte against the list of
 104  * known keyboard IDs.
 105  */
 106
 107 int ps2_is_keyboard_id(char id_byte)
 108 {
 109         static const char keyboard_ids[] = {
 110                 0xab,   /* Regular keyboards            */
 111                 0xac,   /* NCD Sun keyboard             */
 112                 0x2b,   /* Trust keyboard, translated   */
 113                 0x5d,   /* Trust keyboard               */
 114                 0x60,   /* NMB SGI keyboard, translated */
 115                 0x47,   /* NMB SGI keyboard             */
 116         };
 117
 118         return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
 119 }
 120 EXPORT_SYMBOL(ps2_is_keyboard_id);
 121
 122 /*
 123  * ps2_adjust_timeout() is called after receiving 1st byte of command
 124  * response and tries to reduce remaining timeout to speed up command
 125  * completion.
 126  */
 127
 128 static int ps2_adjust_timeout(struct ps2dev *ps2dev, int command, int timeout)
 129 {
 130         switch (command) {
 131                 case PS2_CMD_RESET_BAT:
 132                         /*
 133                          * Device has sent the first response byte after
 134                          * reset command, reset is thus done, so we can
 135                          * shorten the timeout.
 136                          * The next byte will come soon (keyboard) or not
 137                          * at all (mouse).
 138                          */
 139                         if (timeout > msecs_to_jiffies(100))
 140                                 timeout = msecs_to_jiffies(100);
 141                         break;
 142
 143                 case PS2_CMD_GETID:
 144                         /*
 145                          * Microsoft Natural Elite keyboard responds to
 146                          * the GET ID command as it were a mouse, with
 147                          * a single byte. Fail the command so atkbd will
 148                          * use alternative probe to detect it.
 149                          */
 150                         if (ps2dev->cmdbuf[1] == 0xaa) {
 151                                 serio_pause_rx(ps2dev->serio);
 152                                 ps2dev->flags = 0;
 153                                 serio_continue_rx(ps2dev->serio);
 154                                 timeout = 0;
 155                         }
 156
 157                         /*
 158                          * If device behind the port is not a keyboard there
 159                          * won't be 2nd byte of ID response.
 160                          */
 161                         if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
 162                                 serio_pause_rx(ps2dev->serio);
 163                                 ps2dev->flags = ps2dev->cmdcnt = 0;
 164                                 serio_continue_rx(ps2dev->serio);
 165                                 timeout = 0;
 166                         }
 167                         break;
 168
 169                 default:
 170                         break;
 171         }
 172
 173         return timeout;
 174 }
 175
 176 /*
 177  * ps2_command() sends a command and its parameters to the mouse,
 178  * then waits for the response and puts it in the param array.
 179  *
 180  * ps2_command() can only be called from a process context
 181  */
 182
 183 int __ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 184 {
 185         int timeout;
 186         int send = (command >> 12) & 0xf;
 187         int receive = (command >> 8) & 0xf;
 188         int rc = -1;
 189         int i;
 190
 191         if (receive > sizeof(ps2dev->cmdbuf)) {
 192                 WARN_ON(1);
 193                 return -1;
 194         }
 195
 196         if (send && !param) {
 197                 WARN_ON(1);
 198                 return -1;
 199         }
 200
 201         serio_pause_rx(ps2dev->serio);
 202         ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
 203         ps2dev->cmdcnt = receive;
 204         if (receive && param)
 205                 for (i = 0; i < receive; i++)
 206                         ps2dev->cmdbuf[(receive - 1) - i] = param[i];
 207         serio_continue_rx(ps2dev->serio);
 208
 209         /*
 210          * Some devices (Synaptics) peform the reset before
 211          * ACKing the reset command, and so it can take a long
 212          * time before the ACK arrives.
 213          */
 214         if (ps2_sendbyte(ps2dev, command & 0xff,
 215                          command == PS2_CMD_RESET_BAT ? 1000 : 200))
 216                 goto out;
 217
 218         for (i = 0; i < send; i++)
 219                 if (ps2_sendbyte(ps2dev, param[i], 200))
 220                         goto out;
 221
 222         /*
 223          * The reset command takes a long time to execute.
 224          */
 225         timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
 226
 227         timeout = wait_event_timeout(ps2dev->wait,
 228                                      !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
 229
 230         if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
 231
 232                 timeout = ps2_adjust_timeout(ps2dev, command, timeout);
 233                 wait_event_timeout(ps2dev->wait,
 234                                    !(ps2dev->flags & PS2_FLAG_CMD), timeout);
 235         }
 236
 237         if (param)
 238                 for (i = 0; i < receive; i++)
 239                         param[i] = ps2dev->cmdbuf[(receive - 1) - i];
 240
 241         if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
 242                 goto out;
 243
 244         rc = 0;
 245
 246  out:
 247         serio_pause_rx(ps2dev->serio);
 248         ps2dev->flags = 0;
 249         serio_continue_rx(ps2dev->serio);
 250
 251         return rc;
 252 }
 253 EXPORT_SYMBOL(__ps2_command);
 254
 255 int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 256 {
 257         int rc;
 258
 259         ps2_begin_command(ps2dev);
 260         rc = __ps2_command(ps2dev, param, command);
 261         ps2_end_command(ps2dev);
 262
 263         return rc;
 264 }
 265 EXPORT_SYMBOL(ps2_command);
 266
 267 /*
 268  * ps2_init() initializes ps2dev structure
 269  */
 270
 271 void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
 272 {
 273         mutex_init(&ps2dev->cmd_mutex);
 274         lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
 275         init_waitqueue_head(&ps2dev->wait);
 276         ps2dev->serio = serio;
 277 }
 278 EXPORT_SYMBOL(ps2_init);
 279
 280 /*
 281  * ps2_handle_ack() is supposed to be used in interrupt handler
 282  * to properly process ACK/NAK of a command from a PS/2 device.
 283  */
 284
 285 int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
 286 {
 287         switch (data) {
 288                 case PS2_RET_ACK:
 289                         ps2dev->nak = 0;
 290                         break;
 291
 292                 case PS2_RET_NAK:
 293                         ps2dev->flags |= PS2_FLAG_NAK;
 294                         ps2dev->nak = PS2_RET_NAK;
 295                         break;
 296
 297                 case PS2_RET_ERR:
 298                         if (ps2dev->flags & PS2_FLAG_NAK) {
 299                                 ps2dev->flags &= ~PS2_FLAG_NAK;
 300                                 ps2dev->nak = PS2_RET_ERR;
 301                                 break;
 302                         }
 303
 304                 /*
 305                  * Workaround for mice which don't ACK the Get ID command.
 306                  * These are valid mouse IDs that we recognize.
 307                  */
 308                 case 0x00:
 309                 case 0x03:
 310                 case 0x04:
 311                         if (ps2dev->flags & PS2_FLAG_WAITID) {
 312                                 ps2dev->nak = 0;
 313                                 break;
 314                         }
 315                         /* Fall through */
 316                 default:
 317                         return 0;
 318         }
 319
 320
 321         if (!ps2dev->nak) {
 322                 ps2dev->flags &= ~PS2_FLAG_NAK;
 323                 if (ps2dev->cmdcnt)
 324                         ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
 325         }
 326
 327         ps2dev->flags &= ~PS2_FLAG_ACK;
 328         wake_up(&ps2dev->wait);
 329
 330         if (data != PS2_RET_ACK)
 331                 ps2_handle_response(ps2dev, data);
 332
 333         return 1;
 334 }
 335 EXPORT_SYMBOL(ps2_handle_ack);
 336
 337 /*
 338  * ps2_handle_response() is supposed to be used in interrupt handler
 339  * to properly store device's response to a command and notify process
 340  * waiting for completion of the command.
 341  */
 342
 343 int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data)
 344 {
 345         if (ps2dev->cmdcnt)
 346                 ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
 347
 348         if (ps2dev->flags & PS2_FLAG_CMD1) {
 349                 ps2dev->flags &= ~PS2_FLAG_CMD1;
 350                 if (ps2dev->cmdcnt)
 351                         wake_up(&ps2dev->wait);
 352         }
 353
 354         if (!ps2dev->cmdcnt) {
 355                 ps2dev->flags &= ~PS2_FLAG_CMD;
 356                 wake_up(&ps2dev->wait);
 357         }
 358
 359         return 1;
 360 }
 361 EXPORT_SYMBOL(ps2_handle_response);
 362
 363 void ps2_cmd_aborted(struct ps2dev *ps2dev)
 364 {
 365         if (ps2dev->flags & PS2_FLAG_ACK)
 366                 ps2dev->nak = 1;
 367
 368         if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
 369                 wake_up(&ps2dev->wait);
 370
 371         /* reset all flags except last nack */
 372         ps2dev->flags &= PS2_FLAG_NAK;
 373 }
 374 EXPORT_SYMBOL(ps2_cmd_aborted);