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/moduleparam.h>
  17 #include <linux/slab.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/input.h>
  20 #include <linux/serio.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 EXPORT_SYMBOL(ps2_init);
  31 EXPORT_SYMBOL(ps2_sendbyte);
  32 EXPORT_SYMBOL(ps2_drain);
  33 EXPORT_SYMBOL(ps2_command);
  34 EXPORT_SYMBOL(ps2_schedule_command);
  35 EXPORT_SYMBOL(ps2_handle_ack);
  36 EXPORT_SYMBOL(ps2_handle_response);
  37 EXPORT_SYMBOL(ps2_cmd_aborted);
  38
  39 /* Work structure to schedule execution of a command */
  40 struct ps2work {
  41         struct work_struct work;
  42         struct ps2dev *ps2dev;
  43         int command;
  44         unsigned char param[0];
  45 };
  46
  47
  48 /*
  49  * ps2_sendbyte() sends a byte to the device and waits for acknowledge.
  50  * It doesn't handle retransmission, though it could - because if there
  51  * is a need for retransmissions device has to be replaced anyway.
  52  *
  53  * ps2_sendbyte() can only be called from a process context.
  54  */
  55
  56 int ps2_sendbyte(struct ps2dev *ps2dev, unsigned char byte, int timeout)
  57 {
  58         serio_pause_rx(ps2dev->serio);
  59         ps2dev->nak = 1;
  60         ps2dev->flags |= PS2_FLAG_ACK;
  61         serio_continue_rx(ps2dev->serio);
  62
  63         if (serio_write(ps2dev->serio, byte) == 0)
  64                 wait_event_timeout(ps2dev->wait,
  65                                    !(ps2dev->flags & PS2_FLAG_ACK),
  66                                    msecs_to_jiffies(timeout));
  67
  68         serio_pause_rx(ps2dev->serio);
  69         ps2dev->flags &= ~PS2_FLAG_ACK;
  70         serio_continue_rx(ps2dev->serio);
  71
  72         return -ps2dev->nak;
  73 }
  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         down(&ps2dev->cmd_sem);
  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         up(&ps2dev->cmd_sem);
  98 }
  99
 100 /*
 101  * ps2_command() sends a command and its parameters to the mouse,
 102  * then waits for the response and puts it in the param array.
 103  *
 104  * ps2_command() can only be called from a process context
 105  */
 106
 107 int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 108 {
 109         int timeout;
 110         int send = (command >> 12) & 0xf;
 111         int receive = (command >> 8) & 0xf;
 112         int rc = -1;
 113         int i;
 114
 115         if (receive > sizeof(ps2dev->cmdbuf)) {
 116                 WARN_ON(1);
 117                 return -1;
 118         }
 119
 120         down(&ps2dev->cmd_sem);
 121
 122         serio_pause_rx(ps2dev->serio);
 123         ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
 124         ps2dev->cmdcnt = receive;
 125         if (receive && param)
 126                 for (i = 0; i < receive; i++)
 127                         ps2dev->cmdbuf[(receive - 1) - i] = param[i];
 128         serio_continue_rx(ps2dev->serio);
 129
 130         /*
 131          * Some devices (Synaptics) peform the reset before
 132          * ACKing the reset command, and so it can take a long
 133          * time before the ACK arrrives.
 134          */
 135         if (ps2_sendbyte(ps2dev, command & 0xff,
 136                          command == PS2_CMD_RESET_BAT ? 1000 : 200))
 137                 goto out;
 138
 139         for (i = 0; i < send; i++)
 140                 if (ps2_sendbyte(ps2dev, param[i], 200))
 141                         goto out;
 142
 143         /*
 144          * The reset command takes a long time to execute.
 145          */
 146         timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
 147
 148         timeout = wait_event_timeout(ps2dev->wait,
 149                                      !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
 150
 151         if (ps2dev->cmdcnt && timeout > 0) {
 152
 153                 if (command == PS2_CMD_RESET_BAT && timeout > msecs_to_jiffies(100)) {
 154                         /*
 155                          * Device has sent the first response byte
 156                          * after a reset command, reset is thus done,
 157                          * shorten the timeout. The next byte will come
 158                          * soon (keyboard) or not at all (mouse).
 159                          */
 160                         timeout = msecs_to_jiffies(100);
 161                 }
 162
 163                 if (command == PS2_CMD_GETID &&
 164                     ps2dev->cmdbuf[receive - 1] != 0xab && /* Regular keyboards */
 165                     ps2dev->cmdbuf[receive - 1] != 0xac && /* NCD Sun keyboard */
 166                     ps2dev->cmdbuf[receive - 1] != 0x2b && /* Trust keyboard, translated */
 167                     ps2dev->cmdbuf[receive - 1] != 0x5d && /* Trust keyboard */
 168                     ps2dev->cmdbuf[receive - 1] != 0x60 && /* NMB SGI keyboard, translated */
 169                     ps2dev->cmdbuf[receive - 1] != 0x47) { /* NMB SGI keyboard */
 170                         /*
 171                          * Device behind the port is not a keyboard
 172                          * so we don't need to wait for the 2nd byte
 173                          * of ID response.
 174                          */
 175                         serio_pause_rx(ps2dev->serio);
 176                         ps2dev->flags = ps2dev->cmdcnt = 0;
 177                         serio_continue_rx(ps2dev->serio);
 178                 }
 179
 180                 wait_event_timeout(ps2dev->wait,
 181                                    !(ps2dev->flags & PS2_FLAG_CMD), timeout);
 182         }
 183
 184         if (param)
 185                 for (i = 0; i < receive; i++)
 186                         param[i] = ps2dev->cmdbuf[(receive - 1) - i];
 187
 188         if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
 189                 goto out;
 190
 191         rc = 0;
 192
 193 out:
 194         serio_pause_rx(ps2dev->serio);
 195         ps2dev->flags = 0;
 196         serio_continue_rx(ps2dev->serio);
 197
 198         up(&ps2dev->cmd_sem);
 199         return rc;
 200 }
 201
 202 /*
 203  * ps2_execute_scheduled_command() sends a command, previously scheduled by
 204  * ps2_schedule_command(), to a PS/2 device (keyboard, mouse, etc.)
 205  */
 206
 207 static void ps2_execute_scheduled_command(void *data)
 208 {
 209         struct ps2work *ps2work = data;
 210
 211         ps2_command(ps2work->ps2dev, ps2work->param, ps2work->command);
 212         kfree(ps2work);
 213 }
 214
 215 /*
 216  * ps2_schedule_command() allows to schedule delayed execution of a PS/2
 217  * command and can be used to issue a command from an interrupt or softirq
 218  * context.
 219  */
 220
 221 int ps2_schedule_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 222 {
 223         struct ps2work *ps2work;
 224         int send = (command >> 12) & 0xf;
 225         int receive = (command >> 8) & 0xf;
 226
 227         if (!(ps2work = kmalloc(sizeof(struct ps2work) + max(send, receive), GFP_ATOMIC)))
 228                 return -1;
 229
 230         memset(ps2work, 0, sizeof(struct ps2work));
 231         ps2work->ps2dev = ps2dev;
 232         ps2work->command = command;
 233         memcpy(ps2work->param, param, send);
 234         INIT_WORK(&ps2work->work, ps2_execute_scheduled_command, ps2work);
 235
 236         if (!schedule_work(&ps2work->work)) {
 237                 kfree(ps2work);
 238                 return -1;
 239         }
 240
 241         return 0;
 242 }
 243
 244 /*
 245  * ps2_init() initializes ps2dev structure
 246  */
 247
 248 void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
 249 {
 250         init_MUTEX(&ps2dev->cmd_sem);
 251         init_waitqueue_head(&ps2dev->wait);
 252         ps2dev->serio = serio;
 253 }
 254
 255 /*
 256  * ps2_handle_ack() is supposed to be used in interrupt handler
 257  * to properly process ACK/NAK of a command from a PS/2 device.
 258  */
 259
 260 int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
 261 {
 262         switch (data) {
 263                 case PS2_RET_ACK:
 264                         ps2dev->nak = 0;
 265                         break;
 266
 267                 case PS2_RET_NAK:
 268                         ps2dev->nak = 1;
 269                         break;
 270
 271                 /*
 272                  * Workaround for mice which don't ACK the Get ID command.
 273                  * These are valid mouse IDs that we recognize.
 274                  */
 275                 case 0x00:
 276                 case 0x03:
 277                 case 0x04:
 278                         if (ps2dev->flags & PS2_FLAG_WAITID) {
 279                                 ps2dev->nak = 0;
 280                                 break;
 281                         }
 282                         /* Fall through */
 283                 default:
 284                         return 0;
 285         }
 286
 287
 288         if (!ps2dev->nak && ps2dev->cmdcnt)
 289                 ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
 290
 291         ps2dev->flags &= ~PS2_FLAG_ACK;
 292         wake_up(&ps2dev->wait);
 293
 294         if (data != PS2_RET_ACK)
 295                 ps2_handle_response(ps2dev, data);
 296
 297         return 1;
 298 }
 299
 300 /*
 301  * ps2_handle_response() is supposed to be used in interrupt handler
 302  * to properly store device's response to a command and notify process
 303  * waiting for completion of the command.
 304  */
 305
 306 int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data)
 307 {
 308         if (ps2dev->cmdcnt)
 309                 ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
 310
 311         if (ps2dev->flags & PS2_FLAG_CMD1) {
 312                 ps2dev->flags &= ~PS2_FLAG_CMD1;
 313                 if (ps2dev->cmdcnt)
 314                         wake_up(&ps2dev->wait);
 315         }
 316
 317         if (!ps2dev->cmdcnt) {
 318                 ps2dev->flags &= ~PS2_FLAG_CMD;
 319                 wake_up(&ps2dev->wait);
 320         }
 321
 322         return 1;
 323 }
 324
 325 void ps2_cmd_aborted(struct ps2dev *ps2dev)
 326 {
 327         if (ps2dev->flags & PS2_FLAG_ACK)
 328                 ps2dev->nak = 1;
 329
 330         if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
 331                 wake_up(&ps2dev->wait);
 332
 333         ps2dev->flags = 0;
 334 }
 335