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                 serio_pause_rx(ps2dev->serio);
 217                 goto out_reset_flags;
 218         }
 219
 220         for (i = 0; i < send; i++) {
 221                 if (ps2_sendbyte(ps2dev, param[i], 200)) {
 222                         serio_pause_rx(ps2dev->serio);
 223                         goto out_reset_flags;
 224                 }
 225         }
 226
 227         /*
 228          * The reset command takes a long time to execute.
 229          */
 230         timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
 231
 232         timeout = wait_event_timeout(ps2dev->wait,
 233                                      !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
 234
 235         if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
 236
 237                 timeout = ps2_adjust_timeout(ps2dev, command, timeout);
 238                 wait_event_timeout(ps2dev->wait,
 239                                    !(ps2dev->flags & PS2_FLAG_CMD), timeout);
 240         }
 241
 242         serio_pause_rx(ps2dev->serio);
 243
 244         if (param)
 245                 for (i = 0; i < receive; i++)
 246                         param[i] = ps2dev->cmdbuf[(receive - 1) - i];
 247
 248         if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
 249                 goto out_reset_flags;
 250
 251         rc = 0;
 252
 253  out_reset_flags:
 254         ps2dev->flags = 0;
 255         serio_continue_rx(ps2dev->serio);
 256
 257         return rc;
 258 }
 259 EXPORT_SYMBOL(__ps2_command);
 260
 261 int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 262 {
 263         int rc;
 264
 265         ps2_begin_command(ps2dev);
 266         rc = __ps2_command(ps2dev, param, command);
 267         ps2_end_command(ps2dev);
 268
 269         return rc;
 270 }
 271 EXPORT_SYMBOL(ps2_command);
 272
 273 /*
 274  * ps2_init() initializes ps2dev structure
 275  */
 276
 277 void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
 278 {
 279         mutex_init(&ps2dev->cmd_mutex);
 280         lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
 281         init_waitqueue_head(&ps2dev->wait);
 282         ps2dev->serio = serio;
 283 }
 284 EXPORT_SYMBOL(ps2_init);
 285
 286 /*
 287  * ps2_handle_ack() is supposed to be used in interrupt handler
 288  * to properly process ACK/NAK of a command from a PS/2 device.
 289  */
 290
 291 int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
 292 {
 293         switch (data) {
 294                 case PS2_RET_ACK:
 295                         ps2dev->nak = 0;
 296                         break;
 297
 298                 case PS2_RET_NAK:
 299                         ps2dev->flags |= PS2_FLAG_NAK;
 300                         ps2dev->nak = PS2_RET_NAK;
 301                         break;
 302
 303                 case PS2_RET_ERR:
 304                         if (ps2dev->flags & PS2_FLAG_NAK) {
 305                                 ps2dev->flags &= ~PS2_FLAG_NAK;
 306                                 ps2dev->nak = PS2_RET_ERR;
 307                                 break;
 308                         }
 309
 310                 /*
 311                  * Workaround for mice which don't ACK the Get ID command.
 312                  * These are valid mouse IDs that we recognize.
 313                  */
 314                 case 0x00:
 315                 case 0x03:
 316                 case 0x04:
 317                         if (ps2dev->flags & PS2_FLAG_WAITID) {
 318                                 ps2dev->nak = 0;
 319                                 break;
 320                         }
 321                         /* Fall through */
 322                 default:
 323                         return 0;
 324         }
 325
 326
 327         if (!ps2dev->nak) {
 328                 ps2dev->flags &= ~PS2_FLAG_NAK;
 329                 if (ps2dev->cmdcnt)
 330                         ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
 331         }
 332
 333         ps2dev->flags &= ~PS2_FLAG_ACK;
 334         wake_up(&ps2dev->wait);
 335
 336         if (data != PS2_RET_ACK)
 337                 ps2_handle_response(ps2dev, data);
 338
 339         return 1;
 340 }
 341 EXPORT_SYMBOL(ps2_handle_ack);
 342
 343 /*
 344  * ps2_handle_response() is supposed to be used in interrupt handler
 345  * to properly store device's response to a command and notify process
 346  * waiting for completion of the command.
 347  */
 348
 349 int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data)
 350 {
 351         if (ps2dev->cmdcnt)
 352                 ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
 353
 354         if (ps2dev->flags & PS2_FLAG_CMD1) {
 355                 ps2dev->flags &= ~PS2_FLAG_CMD1;
 356                 if (ps2dev->cmdcnt)
 357                         wake_up(&ps2dev->wait);
 358         }
 359
 360         if (!ps2dev->cmdcnt) {
 361                 ps2dev->flags &= ~PS2_FLAG_CMD;
 362                 wake_up(&ps2dev->wait);
 363         }
 364
 365         return 1;
 366 }
 367 EXPORT_SYMBOL(ps2_handle_response);
 368
 369 void ps2_cmd_aborted(struct ps2dev *ps2dev)
 370 {
 371         if (ps2dev->flags & PS2_FLAG_ACK)
 372                 ps2dev->nak = 1;
 373
 374         if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
 375                 wake_up(&ps2dev->wait);
 376
 377         /* reset all flags except last nack */
 378         ps2dev->flags &= PS2_FLAG_NAK;
 379 }
 380 EXPORT_SYMBOL(ps2_cmd_aborted);