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/kref.h> 34 #include <linux/slab.h> 35 #include "sch56xx-common.h" 36 37 /* Insmod parameters */ 38 static int nowayout = WATCHDOG_NOWAYOUT; 39 module_param(nowayout, int, 0); 40 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 41 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 42 43 #define SIO_SCH56XX_LD_EM 0x0C /* Embedded uController Logical Dev */ 44 #define SIO_UNLOCK_KEY 0x55 /* Key to enable Super-I/O */ 45 #define SIO_LOCK_KEY 0xAA /* Key to disable Super-I/O */ 46 47 #define SIO_REG_LDSEL 0x07 /* Logical device select */ 48 #define SIO_REG_DEVID 0x20 /* Device ID */ 49 #define SIO_REG_ENABLE 0x30 /* Logical device enable */ 50 #define SIO_REG_ADDR 0x66 /* Logical device address (2 bytes) */ 51 52 #define SIO_SCH5627_ID 0xC6 /* Chipset ID */ 53 #define SIO_SCH5636_ID 0xC7 /* Chipset ID */ 54 55 #define REGION_LENGTH 10 56 57 #define SCH56XX_CMD_READ 0x02 58 #define SCH56XX_CMD_WRITE 0x03 59 60 /* Watchdog registers */ 61 #define SCH56XX_REG_WDOG_PRESET 0x58B 62 #define SCH56XX_REG_WDOG_CONTROL 0x58C 63 #define SCH56XX_WDOG_TIME_BASE_SEC 0x01 64 #define SCH56XX_REG_WDOG_OUTPUT_ENABLE 0x58E 65 #define SCH56XX_WDOG_OUTPUT_ENABLE 0x02 66 67 struct sch56xx_watchdog_data { 68 u16 addr; 69 struct mutex *io_lock; 70 struct kref kref; 71 struct watchdog_info wdinfo; 72 struct watchdog_device wddev; 73 u8 watchdog_preset; 74 u8 watchdog_control; 75 u8 watchdog_output_enable; 76 }; 77 78 static struct platform_device *sch56xx_pdev; 79 80 /* Super I/O functions */ 81 static inline int superio_inb(int base, int reg) 82 { 83 outb(reg, base); 84 return inb(base + 1); 85 } 86 87 static inline int superio_enter(int base) 88 { 89 /* Don't step on other drivers' I/O space by accident */ 90 if (!request_muxed_region(base, 2, "sch56xx")) { 91 pr_err("I/O address 0x%04x already in use\n", base); 92 return -EBUSY; 93 } 94 95 outb(SIO_UNLOCK_KEY, base); 96 97 return 0; 98 } 99 100 static inline void superio_select(int base, int ld) 101 { 102 outb(SIO_REG_LDSEL, base); 103 outb(ld, base + 1); 104 } 105 106 static inline void superio_exit(int base) 107 { 108 outb(SIO_LOCK_KEY, base); 109 release_region(base, 2); 110 } 111 112 static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v) 113 { 114 u8 val; 115 int i; 116 /* 117 * According to SMSC for the commands we use the maximum time for 118 * the EM to respond is 15 ms, but testing shows in practice it 119 * responds within 15-32 reads, so we first busy poll, and if 120 * that fails sleep a bit and try again until we are way past 121 * the 15 ms maximum response time. 122 */ 123 const int max_busy_polls = 64; 124 const int max_lazy_polls = 32; 125 126 /* (Optional) Write-Clear the EC to Host Mailbox Register */ 127 val = inb(addr + 1); 128 outb(val, addr + 1); 129 130 /* Set Mailbox Address Pointer to first location in Region 1 */ 131 outb(0x00, addr + 2); 132 outb(0x80, addr + 3); 133 134 /* Write Request Packet Header */ 135 outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */ 136 outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */ 137 outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */ 138 139 /* Write Value field */ 140 if (cmd == SCH56XX_CMD_WRITE) 141 outb(v, addr + 4); 142 143 /* Write Address field */ 144 outb(reg & 0xff, addr + 6); 145 outb(reg >> 8, addr + 7); 146 147 /* Execute the Random Access Command */ 148 outb(0x01, addr); /* Write 01h to the Host-to-EC register */ 149 150 /* EM Interface Polling "Algorithm" */ 151 for (i = 0; i < max_busy_polls + max_lazy_polls; i++) { 152 if (i >= max_busy_polls) 153 msleep(1); 154 /* Read Interrupt source Register */ 155 val = inb(addr + 8); 156 /* Write Clear the interrupt source bits */ 157 if (val) 158 outb(val, addr + 8); 159 /* Command Completed ? */ 160 if (val & 0x01) 161 break; 162 } 163 if (i == max_busy_polls + max_lazy_polls) { 164 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n", 165 reg, 1); 166 return -EIO; 167 } 168 169 /* 170 * According to SMSC we may need to retry this, but sofar I've always 171 * seen this succeed in 1 try. 172 */ 173 for (i = 0; i < max_busy_polls; i++) { 174 /* Read EC-to-Host Register */ 175 val = inb(addr + 1); 176 /* Command Completed ? */ 177 if (val == 0x01) 178 break; 179 180 if (i == 0) 181 pr_warn("EC reports: 0x%02x reading virtual register 0x%04hx\n", 182 (unsigned int)val, reg); 183 } 184 if (i == max_busy_polls) { 185 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n", 186 reg, 2); 187 return -EIO; 188 } 189 190 /* 191 * According to the SMSC app note we should now do: 192 * 193 * Set Mailbox Address Pointer to first location in Region 1 * 194 * outb(0x00, addr + 2); 195 * outb(0x80, addr + 3); 196 * 197 * But if we do that things don't work, so let's not. 198 */ 199 200 /* Read Value field */ 201 if (cmd == SCH56XX_CMD_READ) 202 return inb(addr + 4); 203 204 return 0; 205 } 206 207 int sch56xx_read_virtual_reg(u16 addr, u16 reg) 208 { 209 return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0); 210 } 211 EXPORT_SYMBOL(sch56xx_read_virtual_reg); 212 213 int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val) 214 { 215 return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val); 216 } 217 EXPORT_SYMBOL(sch56xx_write_virtual_reg); 218 219 int sch56xx_read_virtual_reg16(u16 addr, u16 reg) 220 { 221 int lsb, msb; 222 223 /* Read LSB first, this will cause the matching MSB to be latched */ 224 lsb = sch56xx_read_virtual_reg(addr, reg); 225 if (lsb < 0) 226 return lsb; 227 228 msb = sch56xx_read_virtual_reg(addr, reg + 1); 229 if (msb < 0) 230 return msb; 231 232 return lsb | (msb << 8); 233 } 234 EXPORT_SYMBOL(sch56xx_read_virtual_reg16); 235 236 int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg, 237 int high_nibble) 238 { 239 int msb, lsn; 240 241 /* Read MSB first, this will cause the matching LSN to be latched */ 242 msb = sch56xx_read_virtual_reg(addr, msb_reg); 243 if (msb < 0) 244 return msb; 245 246 lsn = sch56xx_read_virtual_reg(addr, lsn_reg); 247 if (lsn < 0) 248 return lsn; 249 250 if (high_nibble) 251 return (msb << 4) | (lsn >> 4); 252 else 253 return (msb << 4) | (lsn & 0x0f); 254 } 255 EXPORT_SYMBOL(sch56xx_read_virtual_reg12); 256 257 /* 258 * Watchdog routines 259 */ 260 261 /* Release our data struct when we're unregistered *and* 262 all references to our watchdog device are released */ 263 static void watchdog_release_resources(struct kref *r) 264 { 265 struct sch56xx_watchdog_data *data = 266 container_of(r, struct sch56xx_watchdog_data, kref); 267 kfree(data); 268 } 269 270 static int watchdog_set_timeout(struct watchdog_device *wddev, 271 unsigned int timeout) 272 { 273 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 274 unsigned int resolution; 275 u8 control; 276 int ret; 277 278 /* 1 second or 60 second resolution? */ 279 if (timeout <= 255) 280 resolution = 1; 281 else 282 resolution = 60; 283 284 if (timeout < resolution || timeout > (resolution * 255)) 285 return -EINVAL; 286 287 if (resolution == 1) 288 control = data->watchdog_control | SCH56XX_WDOG_TIME_BASE_SEC; 289 else 290 control = data->watchdog_control & ~SCH56XX_WDOG_TIME_BASE_SEC; 291 292 if (data->watchdog_control != control) { 293 mutex_lock(data->io_lock); 294 ret = sch56xx_write_virtual_reg(data->addr, 295 SCH56XX_REG_WDOG_CONTROL, 296 control); 297 mutex_unlock(data->io_lock); 298 if (ret) 299 return ret; 300 301 data->watchdog_control = control; 302 } 303 304 /* 305 * Remember new timeout value, but do not write as that (re)starts 306 * the watchdog countdown. 307 */ 308 data->watchdog_preset = DIV_ROUND_UP(timeout, resolution); 309 wddev->timeout = data->watchdog_preset * resolution; 310 311 return 0; 312 } 313 314 static int watchdog_start(struct watchdog_device *wddev) 315 { 316 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 317 int ret; 318 u8 val; 319 320 /* 321 * The sch56xx's watchdog cannot really be started / stopped 322 * it is always running, but we can avoid the timer expiring 323 * from causing a system reset by clearing the output enable bit. 324 * 325 * The sch56xx's watchdog will set the watchdog event bit, bit 0 326 * of the second interrupt source register (at base-address + 9), 327 * when the timer expires. 328 * 329 * This will only cause a system reset if the 0-1 flank happens when 330 * output enable is true. Setting output enable after the flank will 331 * not cause a reset, nor will the timer expiring a second time. 332 * This means we must clear the watchdog event bit in case it is set. 333 * 334 * The timer may still be running (after a recent watchdog_stop) and 335 * mere milliseconds away from expiring, so the timer must be reset 336 * first! 337 */ 338 339 mutex_lock(data->io_lock); 340 341 /* 1. Reset the watchdog countdown counter */ 342 ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET, 343 data->watchdog_preset); 344 if (ret) 345 goto leave; 346 347 /* 2. Enable output */ 348 val = data->watchdog_output_enable | SCH56XX_WDOG_OUTPUT_ENABLE; 349 ret = sch56xx_write_virtual_reg(data->addr, 350 SCH56XX_REG_WDOG_OUTPUT_ENABLE, val); 351 if (ret) 352 goto leave; 353 354 data->watchdog_output_enable = val; 355 356 /* 3. Clear the watchdog event bit if set */ 357 val = inb(data->addr + 9); 358 if (val & 0x01) 359 outb(0x01, data->addr + 9); 360 361 leave: 362 mutex_unlock(data->io_lock); 363 return ret; 364 } 365 366 static int watchdog_trigger(struct watchdog_device *wddev) 367 { 368 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 369 int ret; 370 371 /* Reset the watchdog countdown counter */ 372 mutex_lock(data->io_lock); 373 ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET, 374 data->watchdog_preset); 375 mutex_unlock(data->io_lock); 376 377 return ret; 378 } 379 380 static int watchdog_stop(struct watchdog_device *wddev) 381 { 382 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 383 int ret = 0; 384 u8 val; 385 386 val = data->watchdog_output_enable & ~SCH56XX_WDOG_OUTPUT_ENABLE; 387 mutex_lock(data->io_lock); 388 ret = sch56xx_write_virtual_reg(data->addr, 389 SCH56XX_REG_WDOG_OUTPUT_ENABLE, val); 390 mutex_unlock(data->io_lock); 391 if (ret) 392 return ret; 393 394 data->watchdog_output_enable = val; 395 return 0; 396 } 397 398 static void watchdog_ref(struct watchdog_device *wddev) 399 { 400 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 401 402 kref_get(&data->kref); 403 } 404 405 static void watchdog_unref(struct watchdog_device *wddev) 406 { 407 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 408 409 kref_put(&data->kref, watchdog_release_resources); 410 } 411 412 static const struct watchdog_ops watchdog_ops = { 413 .owner = THIS_MODULE, 414 .start = watchdog_start, 415 .stop = watchdog_stop, 416 .ping = watchdog_trigger, 417 .set_timeout = watchdog_set_timeout, 418 .ref = watchdog_ref, 419 .unref = watchdog_unref, 420 }; 421 422 struct sch56xx_watchdog_data *sch56xx_watchdog_register(struct device *parent, 423 u16 addr, u32 revision, struct mutex *io_lock, int check_enabled) 424 { 425 struct sch56xx_watchdog_data *data; 426 int err, control, output_enable; 427 428 /* Cache the watchdog registers */ 429 mutex_lock(io_lock); 430 control = 431 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_CONTROL); 432 output_enable = 433 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE); 434 mutex_unlock(io_lock); 435 436 if (control < 0) 437 return NULL; 438 if (output_enable < 0) 439 return NULL; 440 if (check_enabled && !(output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) { 441 pr_warn("Watchdog not enabled by BIOS, not registering\n"); 442 return NULL; 443 } 444 445 data = kzalloc(sizeof(struct sch56xx_watchdog_data), GFP_KERNEL); 446 if (!data) 447 return NULL; 448 449 data->addr = addr; 450 data->io_lock = io_lock; 451 kref_init(&data->kref); 452 453 strlcpy(data->wdinfo.identity, "sch56xx watchdog", 454 sizeof(data->wdinfo.identity)); 455 data->wdinfo.firmware_version = revision; 456 data->wdinfo.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT; 457 if (!nowayout) 458 data->wdinfo.options |= WDIOF_MAGICCLOSE; 459 460 data->wddev.info = &data->wdinfo; 461 data->wddev.ops = &watchdog_ops; 462 data->wddev.parent = parent; 463 data->wddev.timeout = 60; 464 data->wddev.min_timeout = 1; 465 data->wddev.max_timeout = 255 * 60; 466 if (nowayout) 467 set_bit(WDOG_NO_WAY_OUT, &data->wddev.status); 468 if (output_enable & SCH56XX_WDOG_OUTPUT_ENABLE) 469 set_bit(WDOG_ACTIVE, &data->wddev.status); 470 471 /* Since the watchdog uses a downcounter there is no register to read 472 the BIOS set timeout from (if any was set at all) -> 473 Choose a preset which will give us a 1 minute timeout */ 474 if (control & SCH56XX_WDOG_TIME_BASE_SEC) 475 data->watchdog_preset = 60; /* seconds */ 476 else 477 data->watchdog_preset = 1; /* minute */ 478 479 data->watchdog_control = control; 480 data->watchdog_output_enable = output_enable; 481 482 watchdog_set_drvdata(&data->wddev, data); 483 err = watchdog_register_device(&data->wddev); 484 if (err) { 485 pr_err("Registering watchdog chardev: %d\n", err); 486 kfree(data); 487 return NULL; 488 } 489 490 return data; 491 } 492 EXPORT_SYMBOL(sch56xx_watchdog_register); 493 494 void sch56xx_watchdog_unregister(struct sch56xx_watchdog_data *data) 495 { 496 watchdog_unregister_device(&data->wddev); 497 kref_put(&data->kref, watchdog_release_resources); 498 /* Don't touch data after this it may have been free-ed! */ 499 } 500 EXPORT_SYMBOL(sch56xx_watchdog_unregister); 501 502 /* 503 * platform dev find, add and remove functions 504 */ 505 506 static int __init sch56xx_find(int sioaddr, const char **name) 507 { 508 u8 devid; 509 unsigned short address; 510 int err; 511 512 err = superio_enter(sioaddr); 513 if (err) 514 return err; 515 516 devid = superio_inb(sioaddr, SIO_REG_DEVID); 517 switch (devid) { 518 case SIO_SCH5627_ID: 519 *name = "sch5627"; 520 break; 521 case SIO_SCH5636_ID: 522 *name = "sch5636"; 523 break; 524 default: 525 pr_debug("Unsupported device id: 0x%02x\n", 526 (unsigned int)devid); 527 err = -ENODEV; 528 goto exit; 529 } 530 531 superio_select(sioaddr, SIO_SCH56XX_LD_EM); 532 533 if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) { 534 pr_warn("Device not activated\n"); 535 err = -ENODEV; 536 goto exit; 537 } 538 539 /* 540 * Warning the order of the low / high byte is the other way around 541 * as on most other superio devices!! 542 */ 543 address = superio_inb(sioaddr, SIO_REG_ADDR) | 544 superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8; 545 if (address == 0) { 546 pr_warn("Base address not set\n"); 547 err = -ENODEV; 548 goto exit; 549 } 550 err = address; 551 552 exit: 553 superio_exit(sioaddr); 554 return err; 555 } 556 557 static int __init sch56xx_device_add(int address, const char *name) 558 { 559 struct resource res = { 560 .start = address, 561 .end = address + REGION_LENGTH - 1, 562 .flags = IORESOURCE_IO, 563 }; 564 int err; 565 566 sch56xx_pdev = platform_device_alloc(name, address); 567 if (!sch56xx_pdev) 568 return -ENOMEM; 569 570 res.name = sch56xx_pdev->name; 571 err = acpi_check_resource_conflict(&res); 572 if (err) 573 goto exit_device_put; 574 575 err = platform_device_add_resources(sch56xx_pdev, &res, 1); 576 if (err) { 577 pr_err("Device resource addition failed\n"); 578 goto exit_device_put; 579 } 580 581 err = platform_device_add(sch56xx_pdev); 582 if (err) { 583 pr_err("Device addition failed\n"); 584 goto exit_device_put; 585 } 586 587 return 0; 588 589 exit_device_put: 590 platform_device_put(sch56xx_pdev); 591 592 return err; 593 } 594 595 static int __init sch56xx_init(void) 596 { 597 int address; 598 const char *name = NULL; 599 600 address = sch56xx_find(0x4e, &name); 601 if (address < 0) 602 address = sch56xx_find(0x2e, &name); 603 if (address < 0) 604 return address; 605 606 return sch56xx_device_add(address, name); 607 } 608 609 static void __exit sch56xx_exit(void) 610 { 611 platform_device_unregister(sch56xx_pdev); 612 } 613 614 MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code"); 615 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>"); 616 MODULE_LICENSE("GPL"); 617 618 module_init(sch56xx_init); 619 module_exit(sch56xx_exit); 620