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 mutex_lock(&ps2dev->cmd_mutex); 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 mutex_unlock(&ps2dev->cmd_mutex); 98 } 99 100 /* 101 * ps2_is_keyboard_id() checks received ID byte against the list of 102 * known keyboard IDs. 103 */ 104 105 static inline int ps2_is_keyboard_id(char id_byte) 106 { 107 static char keyboard_ids[] = { 108 0xab, /* Regular keyboards */ 109 0xac, /* NCD Sun keyboard */ 110 0x2b, /* Trust keyboard, translated */ 111 0x5d, /* Trust keyboard */ 112 0x60, /* NMB SGI keyboard, translated */ 113 0x47, /* NMB SGI keyboard */ 114 }; 115 116 return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL; 117 } 118 119 /* 120 * ps2_adjust_timeout() is called after receiving 1st byte of command 121 * response and tries to reduce remaining timeout to speed up command 122 * completion. 123 */ 124 125 static int ps2_adjust_timeout(struct ps2dev *ps2dev, int command, int timeout) 126 { 127 switch (command) { 128 case PS2_CMD_RESET_BAT: 129 /* 130 * Device has sent the first response byte after 131 * reset command, reset is thus done, so we can 132 * shorten the timeout. 133 * The next byte will come soon (keyboard) or not 134 * at all (mouse). 135 */ 136 if (timeout > msecs_to_jiffies(100)) 137 timeout = msecs_to_jiffies(100); 138 break; 139 140 case PS2_CMD_GETID: 141 /* 142 * If device behind the port is not a keyboard there 143 * won't be 2nd byte of ID response. 144 */ 145 if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) { 146 serio_pause_rx(ps2dev->serio); 147 ps2dev->flags = ps2dev->cmdcnt = 0; 148 serio_continue_rx(ps2dev->serio); 149 timeout = 0; 150 } 151 break; 152 153 default: 154 break; 155 } 156 157 return timeout; 158 } 159 160 /* 161 * ps2_command() sends a command and its parameters to the mouse, 162 * then waits for the response and puts it in the param array. 163 * 164 * ps2_command() can only be called from a process context 165 */ 166 167 int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command) 168 { 169 int timeout; 170 int send = (command >> 12) & 0xf; 171 int receive = (command >> 8) & 0xf; 172 int rc = -1; 173 int i; 174 175 if (receive > sizeof(ps2dev->cmdbuf)) { 176 WARN_ON(1); 177 return -1; 178 } 179 180 if (send && !param) { 181 WARN_ON(1); 182 return -1; 183 } 184 185 mutex_lock_nested(&ps2dev->cmd_mutex, SINGLE_DEPTH_NESTING); 186 187 serio_pause_rx(ps2dev->serio); 188 ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0; 189 ps2dev->cmdcnt = receive; 190 if (receive && param) 191 for (i = 0; i < receive; i++) 192 ps2dev->cmdbuf[(receive - 1) - i] = param[i]; 193 serio_continue_rx(ps2dev->serio); 194 195 /* 196 * Some devices (Synaptics) peform the reset before 197 * ACKing the reset command, and so it can take a long 198 * time before the ACK arrrives. 199 */ 200 if (ps2_sendbyte(ps2dev, command & 0xff, 201 command == PS2_CMD_RESET_BAT ? 1000 : 200)) 202 goto out; 203 204 for (i = 0; i < send; i++) 205 if (ps2_sendbyte(ps2dev, param[i], 200)) 206 goto out; 207 208 /* 209 * The reset command takes a long time to execute. 210 */ 211 timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500); 212 213 timeout = wait_event_timeout(ps2dev->wait, 214 !(ps2dev->flags & PS2_FLAG_CMD1), timeout); 215 216 if (ps2dev->cmdcnt && timeout > 0) { 217 218 timeout = ps2_adjust_timeout(ps2dev, command, timeout); 219 wait_event_timeout(ps2dev->wait, 220 !(ps2dev->flags & PS2_FLAG_CMD), timeout); 221 } 222 223 if (param) 224 for (i = 0; i < receive; i++) 225 param[i] = ps2dev->cmdbuf[(receive - 1) - i]; 226 227 if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1)) 228 goto out; 229 230 rc = 0; 231 232 out: 233 serio_pause_rx(ps2dev->serio); 234 ps2dev->flags = 0; 235 serio_continue_rx(ps2dev->serio); 236 237 mutex_unlock(&ps2dev->cmd_mutex); 238 return rc; 239 } 240 241 /* 242 * ps2_execute_scheduled_command() sends a command, previously scheduled by 243 * ps2_schedule_command(), to a PS/2 device (keyboard, mouse, etc.) 244 */ 245 246 static void ps2_execute_scheduled_command(void *data) 247 { 248 struct ps2work *ps2work = data; 249 250 ps2_command(ps2work->ps2dev, ps2work->param, ps2work->command); 251 kfree(ps2work); 252 } 253 254 /* 255 * ps2_schedule_command() allows to schedule delayed execution of a PS/2 256 * command and can be used to issue a command from an interrupt or softirq 257 * context. 258 */ 259 260 int ps2_schedule_command(struct ps2dev *ps2dev, unsigned char *param, int command) 261 { 262 struct ps2work *ps2work; 263 int send = (command >> 12) & 0xf; 264 int receive = (command >> 8) & 0xf; 265 266 if (!(ps2work = kmalloc(sizeof(struct ps2work) + max(send, receive), GFP_ATOMIC))) 267 return -1; 268 269 memset(ps2work, 0, sizeof(struct ps2work)); 270 ps2work->ps2dev = ps2dev; 271 ps2work->command = command; 272 memcpy(ps2work->param, param, send); 273 INIT_WORK(&ps2work->work, ps2_execute_scheduled_command, ps2work); 274 275 if (!schedule_work(&ps2work->work)) { 276 kfree(ps2work); 277 return -1; 278 } 279 280 return 0; 281 } 282 283 /* 284 * ps2_init() initializes ps2dev structure 285 */ 286 287 void ps2_init(struct ps2dev *ps2dev, struct serio *serio) 288 { 289 mutex_init(&ps2dev->cmd_mutex); 290 init_waitqueue_head(&ps2dev->wait); 291 ps2dev->serio = serio; 292 } 293 294 /* 295 * ps2_handle_ack() is supposed to be used in interrupt handler 296 * to properly process ACK/NAK of a command from a PS/2 device. 297 */ 298 299 int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data) 300 { 301 switch (data) { 302 case PS2_RET_ACK: 303 ps2dev->nak = 0; 304 break; 305 306 case PS2_RET_NAK: 307 ps2dev->nak = 1; 308 break; 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 && ps2dev->cmdcnt) 328 ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1; 329 330 ps2dev->flags &= ~PS2_FLAG_ACK; 331 wake_up(&ps2dev->wait); 332 333 if (data != PS2_RET_ACK) 334 ps2_handle_response(ps2dev, data); 335 336 return 1; 337 } 338 339 /* 340 * ps2_handle_response() is supposed to be used in interrupt handler 341 * to properly store device's response to a command and notify process 342 * waiting for completion of the command. 343 */ 344 345 int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data) 346 { 347 if (ps2dev->cmdcnt) 348 ps2dev->cmdbuf[--ps2dev->cmdcnt] = data; 349 350 if (ps2dev->flags & PS2_FLAG_CMD1) { 351 ps2dev->flags &= ~PS2_FLAG_CMD1; 352 if (ps2dev->cmdcnt) 353 wake_up(&ps2dev->wait); 354 } 355 356 if (!ps2dev->cmdcnt) { 357 ps2dev->flags &= ~PS2_FLAG_CMD; 358 wake_up(&ps2dev->wait); 359 } 360 361 return 1; 362 } 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 ps2dev->flags = 0; 373 } 374 375