1 /*************************************************************************** 2 * Copyright (C) 2010-2012 Hans de Goede <hdegoede@redhat.com> * 3 * * 4 * This program is free software; you can redistribute it and/or modify * 5 * it under the terms of the GNU General Public License as published by * 6 * the Free Software Foundation; either version 2 of the License, or * 7 * (at your option) any later version. * 8 * * 9 * This program is distributed in the hope that it will be useful, * 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of * 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * 12 * GNU General Public License for more details. * 13 * * 14 * You should have received a copy of the GNU General Public License * 15 * along with this program; if not, write to the * 16 * Free Software Foundation, Inc., * 17 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * 18 ***************************************************************************/ 19 20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 21 22 #include <linux/module.h> 23 #include <linux/init.h> 24 #include <linux/platform_device.h> 25 #include <linux/err.h> 26 #include <linux/io.h> 27 #include <linux/acpi.h> 28 #include <linux/delay.h> 29 #include <linux/fs.h> 30 #include <linux/watchdog.h> 31 #include <linux/miscdevice.h> 32 #include <linux/uaccess.h> 33 #include <linux/slab.h> 34 #include "sch56xx-common.h" 35 36 /* Insmod parameters */ 37 static int nowayout = WATCHDOG_NOWAYOUT; 38 module_param(nowayout, int, 0); 39 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 40 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 41 42 #define SIO_SCH56XX_LD_EM 0x0C /* Embedded uController Logical Dev */ 43 #define SIO_UNLOCK_KEY 0x55 /* Key to enable Super-I/O */ 44 #define SIO_LOCK_KEY 0xAA /* Key to disable Super-I/O */ 45 46 #define SIO_REG_LDSEL 0x07 /* Logical device select */ 47 #define SIO_REG_DEVID 0x20 /* Device ID */ 48 #define SIO_REG_ENABLE 0x30 /* Logical device enable */ 49 #define SIO_REG_ADDR 0x66 /* Logical device address (2 bytes) */ 50 51 #define SIO_SCH5627_ID 0xC6 /* Chipset ID */ 52 #define SIO_SCH5636_ID 0xC7 /* Chipset ID */ 53 54 #define REGION_LENGTH 10 55 56 #define SCH56XX_CMD_READ 0x02 57 #define SCH56XX_CMD_WRITE 0x03 58 59 /* Watchdog registers */ 60 #define SCH56XX_REG_WDOG_PRESET 0x58B 61 #define SCH56XX_REG_WDOG_CONTROL 0x58C 62 #define SCH56XX_WDOG_TIME_BASE_SEC 0x01 63 #define SCH56XX_REG_WDOG_OUTPUT_ENABLE 0x58E 64 #define SCH56XX_WDOG_OUTPUT_ENABLE 0x02 65 66 struct sch56xx_watchdog_data { 67 u16 addr; 68 struct mutex *io_lock; 69 struct watchdog_info wdinfo; 70 struct watchdog_device wddev; 71 u8 watchdog_preset; 72 u8 watchdog_control; 73 u8 watchdog_output_enable; 74 }; 75 76 static struct platform_device *sch56xx_pdev; 77 78 /* Super I/O functions */ 79 static inline int superio_inb(int base, int reg) 80 { 81 outb(reg, base); 82 return inb(base + 1); 83 } 84 85 static inline int superio_enter(int base) 86 { 87 /* Don't step on other drivers' I/O space by accident */ 88 if (!request_muxed_region(base, 2, "sch56xx")) { 89 pr_err("I/O address 0x%04x already in use\n", base); 90 return -EBUSY; 91 } 92 93 outb(SIO_UNLOCK_KEY, base); 94 95 return 0; 96 } 97 98 static inline void superio_select(int base, int ld) 99 { 100 outb(SIO_REG_LDSEL, base); 101 outb(ld, base + 1); 102 } 103 104 static inline void superio_exit(int base) 105 { 106 outb(SIO_LOCK_KEY, base); 107 release_region(base, 2); 108 } 109 110 static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v) 111 { 112 u8 val; 113 int i; 114 /* 115 * According to SMSC for the commands we use the maximum time for 116 * the EM to respond is 15 ms, but testing shows in practice it 117 * responds within 15-32 reads, so we first busy poll, and if 118 * that fails sleep a bit and try again until we are way past 119 * the 15 ms maximum response time. 120 */ 121 const int max_busy_polls = 64; 122 const int max_lazy_polls = 32; 123 124 /* (Optional) Write-Clear the EC to Host Mailbox Register */ 125 val = inb(addr + 1); 126 outb(val, addr + 1); 127 128 /* Set Mailbox Address Pointer to first location in Region 1 */ 129 outb(0x00, addr + 2); 130 outb(0x80, addr + 3); 131 132 /* Write Request Packet Header */ 133 outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */ 134 outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */ 135 outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */ 136 137 /* Write Value field */ 138 if (cmd == SCH56XX_CMD_WRITE) 139 outb(v, addr + 4); 140 141 /* Write Address field */ 142 outb(reg & 0xff, addr + 6); 143 outb(reg >> 8, addr + 7); 144 145 /* Execute the Random Access Command */ 146 outb(0x01, addr); /* Write 01h to the Host-to-EC register */ 147 148 /* EM Interface Polling "Algorithm" */ 149 for (i = 0; i < max_busy_polls + max_lazy_polls; i++) { 150 if (i >= max_busy_polls) 151 msleep(1); 152 /* Read Interrupt source Register */ 153 val = inb(addr + 8); 154 /* Write Clear the interrupt source bits */ 155 if (val) 156 outb(val, addr + 8); 157 /* Command Completed ? */ 158 if (val & 0x01) 159 break; 160 } 161 if (i == max_busy_polls + max_lazy_polls) { 162 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n", 163 reg, 1); 164 return -EIO; 165 } 166 167 /* 168 * According to SMSC we may need to retry this, but sofar I've always 169 * seen this succeed in 1 try. 170 */ 171 for (i = 0; i < max_busy_polls; i++) { 172 /* Read EC-to-Host Register */ 173 val = inb(addr + 1); 174 /* Command Completed ? */ 175 if (val == 0x01) 176 break; 177 178 if (i == 0) 179 pr_warn("EC reports: 0x%02x reading virtual register 0x%04hx\n", 180 (unsigned int)val, reg); 181 } 182 if (i == max_busy_polls) { 183 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n", 184 reg, 2); 185 return -EIO; 186 } 187 188 /* 189 * According to the SMSC app note we should now do: 190 * 191 * Set Mailbox Address Pointer to first location in Region 1 * 192 * outb(0x00, addr + 2); 193 * outb(0x80, addr + 3); 194 * 195 * But if we do that things don't work, so let's not. 196 */ 197 198 /* Read Value field */ 199 if (cmd == SCH56XX_CMD_READ) 200 return inb(addr + 4); 201 202 return 0; 203 } 204 205 int sch56xx_read_virtual_reg(u16 addr, u16 reg) 206 { 207 return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0); 208 } 209 EXPORT_SYMBOL(sch56xx_read_virtual_reg); 210 211 int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val) 212 { 213 return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val); 214 } 215 EXPORT_SYMBOL(sch56xx_write_virtual_reg); 216 217 int sch56xx_read_virtual_reg16(u16 addr, u16 reg) 218 { 219 int lsb, msb; 220 221 /* Read LSB first, this will cause the matching MSB to be latched */ 222 lsb = sch56xx_read_virtual_reg(addr, reg); 223 if (lsb < 0) 224 return lsb; 225 226 msb = sch56xx_read_virtual_reg(addr, reg + 1); 227 if (msb < 0) 228 return msb; 229 230 return lsb | (msb << 8); 231 } 232 EXPORT_SYMBOL(sch56xx_read_virtual_reg16); 233 234 int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg, 235 int high_nibble) 236 { 237 int msb, lsn; 238 239 /* Read MSB first, this will cause the matching LSN to be latched */ 240 msb = sch56xx_read_virtual_reg(addr, msb_reg); 241 if (msb < 0) 242 return msb; 243 244 lsn = sch56xx_read_virtual_reg(addr, lsn_reg); 245 if (lsn < 0) 246 return lsn; 247 248 if (high_nibble) 249 return (msb << 4) | (lsn >> 4); 250 else 251 return (msb << 4) | (lsn & 0x0f); 252 } 253 EXPORT_SYMBOL(sch56xx_read_virtual_reg12); 254 255 /* 256 * Watchdog routines 257 */ 258 259 static int watchdog_set_timeout(struct watchdog_device *wddev, 260 unsigned int timeout) 261 { 262 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 263 unsigned int resolution; 264 u8 control; 265 int ret; 266 267 /* 1 second or 60 second resolution? */ 268 if (timeout <= 255) 269 resolution = 1; 270 else 271 resolution = 60; 272 273 if (timeout < resolution || timeout > (resolution * 255)) 274 return -EINVAL; 275 276 if (resolution == 1) 277 control = data->watchdog_control | SCH56XX_WDOG_TIME_BASE_SEC; 278 else 279 control = data->watchdog_control & ~SCH56XX_WDOG_TIME_BASE_SEC; 280 281 if (data->watchdog_control != control) { 282 mutex_lock(data->io_lock); 283 ret = sch56xx_write_virtual_reg(data->addr, 284 SCH56XX_REG_WDOG_CONTROL, 285 control); 286 mutex_unlock(data->io_lock); 287 if (ret) 288 return ret; 289 290 data->watchdog_control = control; 291 } 292 293 /* 294 * Remember new timeout value, but do not write as that (re)starts 295 * the watchdog countdown. 296 */ 297 data->watchdog_preset = DIV_ROUND_UP(timeout, resolution); 298 wddev->timeout = data->watchdog_preset * resolution; 299 300 return 0; 301 } 302 303 static int watchdog_start(struct watchdog_device *wddev) 304 { 305 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 306 int ret; 307 u8 val; 308 309 /* 310 * The sch56xx's watchdog cannot really be started / stopped 311 * it is always running, but we can avoid the timer expiring 312 * from causing a system reset by clearing the output enable bit. 313 * 314 * The sch56xx's watchdog will set the watchdog event bit, bit 0 315 * of the second interrupt source register (at base-address + 9), 316 * when the timer expires. 317 * 318 * This will only cause a system reset if the 0-1 flank happens when 319 * output enable is true. Setting output enable after the flank will 320 * not cause a reset, nor will the timer expiring a second time. 321 * This means we must clear the watchdog event bit in case it is set. 322 * 323 * The timer may still be running (after a recent watchdog_stop) and 324 * mere milliseconds away from expiring, so the timer must be reset 325 * first! 326 */ 327 328 mutex_lock(data->io_lock); 329 330 /* 1. Reset the watchdog countdown counter */ 331 ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET, 332 data->watchdog_preset); 333 if (ret) 334 goto leave; 335 336 /* 2. Enable output */ 337 val = data->watchdog_output_enable | SCH56XX_WDOG_OUTPUT_ENABLE; 338 ret = sch56xx_write_virtual_reg(data->addr, 339 SCH56XX_REG_WDOG_OUTPUT_ENABLE, val); 340 if (ret) 341 goto leave; 342 343 data->watchdog_output_enable = val; 344 345 /* 3. Clear the watchdog event bit if set */ 346 val = inb(data->addr + 9); 347 if (val & 0x01) 348 outb(0x01, data->addr + 9); 349 350 leave: 351 mutex_unlock(data->io_lock); 352 return ret; 353 } 354 355 static int watchdog_trigger(struct watchdog_device *wddev) 356 { 357 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 358 int ret; 359 360 /* Reset the watchdog countdown counter */ 361 mutex_lock(data->io_lock); 362 ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET, 363 data->watchdog_preset); 364 mutex_unlock(data->io_lock); 365 366 return ret; 367 } 368 369 static int watchdog_stop(struct watchdog_device *wddev) 370 { 371 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 372 int ret = 0; 373 u8 val; 374 375 val = data->watchdog_output_enable & ~SCH56XX_WDOG_OUTPUT_ENABLE; 376 mutex_lock(data->io_lock); 377 ret = sch56xx_write_virtual_reg(data->addr, 378 SCH56XX_REG_WDOG_OUTPUT_ENABLE, val); 379 mutex_unlock(data->io_lock); 380 if (ret) 381 return ret; 382 383 data->watchdog_output_enable = val; 384 return 0; 385 } 386 387 static const struct watchdog_ops watchdog_ops = { 388 .owner = THIS_MODULE, 389 .start = watchdog_start, 390 .stop = watchdog_stop, 391 .ping = watchdog_trigger, 392 .set_timeout = watchdog_set_timeout, 393 }; 394 395 struct sch56xx_watchdog_data *sch56xx_watchdog_register(struct device *parent, 396 u16 addr, u32 revision, struct mutex *io_lock, int check_enabled) 397 { 398 struct sch56xx_watchdog_data *data; 399 int err, control, output_enable; 400 401 /* Cache the watchdog registers */ 402 mutex_lock(io_lock); 403 control = 404 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_CONTROL); 405 output_enable = 406 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE); 407 mutex_unlock(io_lock); 408 409 if (control < 0) 410 return NULL; 411 if (output_enable < 0) 412 return NULL; 413 if (check_enabled && !(output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) { 414 pr_warn("Watchdog not enabled by BIOS, not registering\n"); 415 return NULL; 416 } 417 418 data = kzalloc(sizeof(struct sch56xx_watchdog_data), GFP_KERNEL); 419 if (!data) 420 return NULL; 421 422 data->addr = addr; 423 data->io_lock = io_lock; 424 425 strlcpy(data->wdinfo.identity, "sch56xx watchdog", 426 sizeof(data->wdinfo.identity)); 427 data->wdinfo.firmware_version = revision; 428 data->wdinfo.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT; 429 if (!nowayout) 430 data->wdinfo.options |= WDIOF_MAGICCLOSE; 431 432 data->wddev.info = &data->wdinfo; 433 data->wddev.ops = &watchdog_ops; 434 data->wddev.parent = parent; 435 data->wddev.timeout = 60; 436 data->wddev.min_timeout = 1; 437 data->wddev.max_timeout = 255 * 60; 438 if (nowayout) 439 set_bit(WDOG_NO_WAY_OUT, &data->wddev.status); 440 if (output_enable & SCH56XX_WDOG_OUTPUT_ENABLE) 441 set_bit(WDOG_ACTIVE, &data->wddev.status); 442 443 /* Since the watchdog uses a downcounter there is no register to read 444 the BIOS set timeout from (if any was set at all) -> 445 Choose a preset which will give us a 1 minute timeout */ 446 if (control & SCH56XX_WDOG_TIME_BASE_SEC) 447 data->watchdog_preset = 60; /* seconds */ 448 else 449 data->watchdog_preset = 1; /* minute */ 450 451 data->watchdog_control = control; 452 data->watchdog_output_enable = output_enable; 453 454 watchdog_set_drvdata(&data->wddev, data); 455 err = watchdog_register_device(&data->wddev); 456 if (err) { 457 pr_err("Registering watchdog chardev: %d\n", err); 458 kfree(data); 459 return NULL; 460 } 461 462 return data; 463 } 464 EXPORT_SYMBOL(sch56xx_watchdog_register); 465 466 void sch56xx_watchdog_unregister(struct sch56xx_watchdog_data *data) 467 { 468 watchdog_unregister_device(&data->wddev); 469 kfree(data); 470 } 471 EXPORT_SYMBOL(sch56xx_watchdog_unregister); 472 473 /* 474 * platform dev find, add and remove functions 475 */ 476 477 static int __init sch56xx_find(int sioaddr, const char **name) 478 { 479 u8 devid; 480 unsigned short address; 481 int err; 482 483 err = superio_enter(sioaddr); 484 if (err) 485 return err; 486 487 devid = superio_inb(sioaddr, SIO_REG_DEVID); 488 switch (devid) { 489 case SIO_SCH5627_ID: 490 *name = "sch5627"; 491 break; 492 case SIO_SCH5636_ID: 493 *name = "sch5636"; 494 break; 495 default: 496 pr_debug("Unsupported device id: 0x%02x\n", 497 (unsigned int)devid); 498 err = -ENODEV; 499 goto exit; 500 } 501 502 superio_select(sioaddr, SIO_SCH56XX_LD_EM); 503 504 if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) { 505 pr_warn("Device not activated\n"); 506 err = -ENODEV; 507 goto exit; 508 } 509 510 /* 511 * Warning the order of the low / high byte is the other way around 512 * as on most other superio devices!! 513 */ 514 address = superio_inb(sioaddr, SIO_REG_ADDR) | 515 superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8; 516 if (address == 0) { 517 pr_warn("Base address not set\n"); 518 err = -ENODEV; 519 goto exit; 520 } 521 err = address; 522 523 exit: 524 superio_exit(sioaddr); 525 return err; 526 } 527 528 static int __init sch56xx_device_add(int address, const char *name) 529 { 530 struct resource res = { 531 .start = address, 532 .end = address + REGION_LENGTH - 1, 533 .flags = IORESOURCE_IO, 534 }; 535 int err; 536 537 sch56xx_pdev = platform_device_alloc(name, address); 538 if (!sch56xx_pdev) 539 return -ENOMEM; 540 541 res.name = sch56xx_pdev->name; 542 err = acpi_check_resource_conflict(&res); 543 if (err) 544 goto exit_device_put; 545 546 err = platform_device_add_resources(sch56xx_pdev, &res, 1); 547 if (err) { 548 pr_err("Device resource addition failed\n"); 549 goto exit_device_put; 550 } 551 552 err = platform_device_add(sch56xx_pdev); 553 if (err) { 554 pr_err("Device addition failed\n"); 555 goto exit_device_put; 556 } 557 558 return 0; 559 560 exit_device_put: 561 platform_device_put(sch56xx_pdev); 562 563 return err; 564 } 565 566 static int __init sch56xx_init(void) 567 { 568 int address; 569 const char *name = NULL; 570 571 address = sch56xx_find(0x4e, &name); 572 if (address < 0) 573 address = sch56xx_find(0x2e, &name); 574 if (address < 0) 575 return address; 576 577 return sch56xx_device_add(address, name); 578 } 579 580 static void __exit sch56xx_exit(void) 581 { 582 platform_device_unregister(sch56xx_pdev); 583 } 584 585 MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code"); 586 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>"); 587 MODULE_LICENSE("GPL"); 588 589 module_init(sch56xx_init); 590 module_exit(sch56xx_exit); 591