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); 335