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