1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /*************************************************************************** 3 * Copyright (C) 2010-2012 Hans de Goede <hdegoede@redhat.com> * 4 * * 5 ***************************************************************************/ 6 7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 8 9 #include <linux/module.h> 10 #include <linux/init.h> 11 #include <linux/platform_device.h> 12 #include <linux/err.h> 13 #include <linux/io.h> 14 #include <linux/acpi.h> 15 #include <linux/delay.h> 16 #include <linux/fs.h> 17 #include <linux/watchdog.h> 18 #include <linux/uaccess.h> 19 #include <linux/slab.h> 20 #include "sch56xx-common.h" 21 22 /* Insmod parameters */ 23 static int nowayout = WATCHDOG_NOWAYOUT; 24 module_param(nowayout, int, 0); 25 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 26 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 27 28 #define SIO_SCH56XX_LD_EM 0x0C /* Embedded uController Logical Dev */ 29 #define SIO_UNLOCK_KEY 0x55 /* Key to enable Super-I/O */ 30 #define SIO_LOCK_KEY 0xAA /* Key to disable Super-I/O */ 31 32 #define SIO_REG_LDSEL 0x07 /* Logical device select */ 33 #define SIO_REG_DEVID 0x20 /* Device ID */ 34 #define SIO_REG_ENABLE 0x30 /* Logical device enable */ 35 #define SIO_REG_ADDR 0x66 /* Logical device address (2 bytes) */ 36 37 #define SIO_SCH5627_ID 0xC6 /* Chipset ID */ 38 #define SIO_SCH5636_ID 0xC7 /* Chipset ID */ 39 40 #define REGION_LENGTH 10 41 42 #define SCH56XX_CMD_READ 0x02 43 #define SCH56XX_CMD_WRITE 0x03 44 45 /* Watchdog registers */ 46 #define SCH56XX_REG_WDOG_PRESET 0x58B 47 #define SCH56XX_REG_WDOG_CONTROL 0x58C 48 #define SCH56XX_WDOG_TIME_BASE_SEC 0x01 49 #define SCH56XX_REG_WDOG_OUTPUT_ENABLE 0x58E 50 #define SCH56XX_WDOG_OUTPUT_ENABLE 0x02 51 52 struct sch56xx_watchdog_data { 53 u16 addr; 54 struct mutex *io_lock; 55 struct watchdog_info wdinfo; 56 struct watchdog_device wddev; 57 u8 watchdog_preset; 58 u8 watchdog_control; 59 u8 watchdog_output_enable; 60 }; 61 62 static struct platform_device *sch56xx_pdev; 63 64 /* Super I/O functions */ 65 static inline int superio_inb(int base, int reg) 66 { 67 outb(reg, base); 68 return inb(base + 1); 69 } 70 71 static inline int superio_enter(int base) 72 { 73 /* Don't step on other drivers' I/O space by accident */ 74 if (!request_muxed_region(base, 2, "sch56xx")) { 75 pr_err("I/O address 0x%04x already in use\n", base); 76 return -EBUSY; 77 } 78 79 outb(SIO_UNLOCK_KEY, base); 80 81 return 0; 82 } 83 84 static inline void superio_select(int base, int ld) 85 { 86 outb(SIO_REG_LDSEL, base); 87 outb(ld, base + 1); 88 } 89 90 static inline void superio_exit(int base) 91 { 92 outb(SIO_LOCK_KEY, base); 93 release_region(base, 2); 94 } 95 96 static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v) 97 { 98 u8 val; 99 int i; 100 /* 101 * According to SMSC for the commands we use the maximum time for 102 * the EM to respond is 15 ms, but testing shows in practice it 103 * responds within 15-32 reads, so we first busy poll, and if 104 * that fails sleep a bit and try again until we are way past 105 * the 15 ms maximum response time. 106 */ 107 const int max_busy_polls = 64; 108 const int max_lazy_polls = 32; 109 110 /* (Optional) Write-Clear the EC to Host Mailbox Register */ 111 val = inb(addr + 1); 112 outb(val, addr + 1); 113 114 /* Set Mailbox Address Pointer to first location in Region 1 */ 115 outb(0x00, addr + 2); 116 outb(0x80, addr + 3); 117 118 /* Write Request Packet Header */ 119 outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */ 120 outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */ 121 outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */ 122 123 /* Write Value field */ 124 if (cmd == SCH56XX_CMD_WRITE) 125 outb(v, addr + 4); 126 127 /* Write Address field */ 128 outb(reg & 0xff, addr + 6); 129 outb(reg >> 8, addr + 7); 130 131 /* Execute the Random Access Command */ 132 outb(0x01, addr); /* Write 01h to the Host-to-EC register */ 133 134 /* EM Interface Polling "Algorithm" */ 135 for (i = 0; i < max_busy_polls + max_lazy_polls; i++) { 136 if (i >= max_busy_polls) 137 msleep(1); 138 /* Read Interrupt source Register */ 139 val = inb(addr + 8); 140 /* Write Clear the interrupt source bits */ 141 if (val) 142 outb(val, addr + 8); 143 /* Command Completed ? */ 144 if (val & 0x01) 145 break; 146 } 147 if (i == max_busy_polls + max_lazy_polls) { 148 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n", 149 reg, 1); 150 return -EIO; 151 } 152 153 /* 154 * According to SMSC we may need to retry this, but sofar I've always 155 * seen this succeed in 1 try. 156 */ 157 for (i = 0; i < max_busy_polls; i++) { 158 /* Read EC-to-Host Register */ 159 val = inb(addr + 1); 160 /* Command Completed ? */ 161 if (val == 0x01) 162 break; 163 164 if (i == 0) 165 pr_warn("EC reports: 0x%02x reading virtual register 0x%04hx\n", 166 (unsigned int)val, reg); 167 } 168 if (i == max_busy_polls) { 169 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n", 170 reg, 2); 171 return -EIO; 172 } 173 174 /* 175 * According to the SMSC app note we should now do: 176 * 177 * Set Mailbox Address Pointer to first location in Region 1 * 178 * outb(0x00, addr + 2); 179 * outb(0x80, addr + 3); 180 * 181 * But if we do that things don't work, so let's not. 182 */ 183 184 /* Read Value field */ 185 if (cmd == SCH56XX_CMD_READ) 186 return inb(addr + 4); 187 188 return 0; 189 } 190 191 int sch56xx_read_virtual_reg(u16 addr, u16 reg) 192 { 193 return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0); 194 } 195 EXPORT_SYMBOL(sch56xx_read_virtual_reg); 196 197 int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val) 198 { 199 return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val); 200 } 201 EXPORT_SYMBOL(sch56xx_write_virtual_reg); 202 203 int sch56xx_read_virtual_reg16(u16 addr, u16 reg) 204 { 205 int lsb, msb; 206 207 /* Read LSB first, this will cause the matching MSB to be latched */ 208 lsb = sch56xx_read_virtual_reg(addr, reg); 209 if (lsb < 0) 210 return lsb; 211 212 msb = sch56xx_read_virtual_reg(addr, reg + 1); 213 if (msb < 0) 214 return msb; 215 216 return lsb | (msb << 8); 217 } 218 EXPORT_SYMBOL(sch56xx_read_virtual_reg16); 219 220 int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg, 221 int high_nibble) 222 { 223 int msb, lsn; 224 225 /* Read MSB first, this will cause the matching LSN to be latched */ 226 msb = sch56xx_read_virtual_reg(addr, msb_reg); 227 if (msb < 0) 228 return msb; 229 230 lsn = sch56xx_read_virtual_reg(addr, lsn_reg); 231 if (lsn < 0) 232 return lsn; 233 234 if (high_nibble) 235 return (msb << 4) | (lsn >> 4); 236 else 237 return (msb << 4) | (lsn & 0x0f); 238 } 239 EXPORT_SYMBOL(sch56xx_read_virtual_reg12); 240 241 /* 242 * Watchdog routines 243 */ 244 245 static int watchdog_set_timeout(struct watchdog_device *wddev, 246 unsigned int timeout) 247 { 248 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 249 unsigned int resolution; 250 u8 control; 251 int ret; 252 253 /* 1 second or 60 second resolution? */ 254 if (timeout <= 255) 255 resolution = 1; 256 else 257 resolution = 60; 258 259 if (timeout < resolution || timeout > (resolution * 255)) 260 return -EINVAL; 261 262 if (resolution == 1) 263 control = data->watchdog_control | SCH56XX_WDOG_TIME_BASE_SEC; 264 else 265 control = data->watchdog_control & ~SCH56XX_WDOG_TIME_BASE_SEC; 266 267 if (data->watchdog_control != control) { 268 mutex_lock(data->io_lock); 269 ret = sch56xx_write_virtual_reg(data->addr, 270 SCH56XX_REG_WDOG_CONTROL, 271 control); 272 mutex_unlock(data->io_lock); 273 if (ret) 274 return ret; 275 276 data->watchdog_control = control; 277 } 278 279 /* 280 * Remember new timeout value, but do not write as that (re)starts 281 * the watchdog countdown. 282 */ 283 data->watchdog_preset = DIV_ROUND_UP(timeout, resolution); 284 wddev->timeout = data->watchdog_preset * resolution; 285 286 return 0; 287 } 288 289 static int watchdog_start(struct watchdog_device *wddev) 290 { 291 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 292 int ret; 293 u8 val; 294 295 /* 296 * The sch56xx's watchdog cannot really be started / stopped 297 * it is always running, but we can avoid the timer expiring 298 * from causing a system reset by clearing the output enable bit. 299 * 300 * The sch56xx's watchdog will set the watchdog event bit, bit 0 301 * of the second interrupt source register (at base-address + 9), 302 * when the timer expires. 303 * 304 * This will only cause a system reset if the 0-1 flank happens when 305 * output enable is true. Setting output enable after the flank will 306 * not cause a reset, nor will the timer expiring a second time. 307 * This means we must clear the watchdog event bit in case it is set. 308 * 309 * The timer may still be running (after a recent watchdog_stop) and 310 * mere milliseconds away from expiring, so the timer must be reset 311 * first! 312 */ 313 314 mutex_lock(data->io_lock); 315 316 /* 1. Reset the watchdog countdown counter */ 317 ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET, 318 data->watchdog_preset); 319 if (ret) 320 goto leave; 321 322 /* 2. Enable output */ 323 val = data->watchdog_output_enable | SCH56XX_WDOG_OUTPUT_ENABLE; 324 ret = sch56xx_write_virtual_reg(data->addr, 325 SCH56XX_REG_WDOG_OUTPUT_ENABLE, val); 326 if (ret) 327 goto leave; 328 329 data->watchdog_output_enable = val; 330 331 /* 3. Clear the watchdog event bit if set */ 332 val = inb(data->addr + 9); 333 if (val & 0x01) 334 outb(0x01, data->addr + 9); 335 336 leave: 337 mutex_unlock(data->io_lock); 338 return ret; 339 } 340 341 static int watchdog_trigger(struct watchdog_device *wddev) 342 { 343 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 344 int ret; 345 346 /* Reset the watchdog countdown counter */ 347 mutex_lock(data->io_lock); 348 ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET, 349 data->watchdog_preset); 350 mutex_unlock(data->io_lock); 351 352 return ret; 353 } 354 355 static int watchdog_stop(struct watchdog_device *wddev) 356 { 357 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 358 int ret = 0; 359 u8 val; 360 361 val = data->watchdog_output_enable & ~SCH56XX_WDOG_OUTPUT_ENABLE; 362 mutex_lock(data->io_lock); 363 ret = sch56xx_write_virtual_reg(data->addr, 364 SCH56XX_REG_WDOG_OUTPUT_ENABLE, val); 365 mutex_unlock(data->io_lock); 366 if (ret) 367 return ret; 368 369 data->watchdog_output_enable = val; 370 return 0; 371 } 372 373 static const struct watchdog_ops watchdog_ops = { 374 .owner = THIS_MODULE, 375 .start = watchdog_start, 376 .stop = watchdog_stop, 377 .ping = watchdog_trigger, 378 .set_timeout = watchdog_set_timeout, 379 }; 380 381 struct sch56xx_watchdog_data *sch56xx_watchdog_register(struct device *parent, 382 u16 addr, u32 revision, struct mutex *io_lock, int check_enabled) 383 { 384 struct sch56xx_watchdog_data *data; 385 int err, control, output_enable; 386 387 /* Cache the watchdog registers */ 388 mutex_lock(io_lock); 389 control = 390 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_CONTROL); 391 output_enable = 392 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE); 393 mutex_unlock(io_lock); 394 395 if (control < 0) 396 return NULL; 397 if (output_enable < 0) 398 return NULL; 399 if (check_enabled && !(output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) { 400 pr_warn("Watchdog not enabled by BIOS, not registering\n"); 401 return NULL; 402 } 403 404 data = kzalloc(sizeof(struct sch56xx_watchdog_data), GFP_KERNEL); 405 if (!data) 406 return NULL; 407 408 data->addr = addr; 409 data->io_lock = io_lock; 410 411 strlcpy(data->wdinfo.identity, "sch56xx watchdog", 412 sizeof(data->wdinfo.identity)); 413 data->wdinfo.firmware_version = revision; 414 data->wdinfo.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT; 415 if (!nowayout) 416 data->wdinfo.options |= WDIOF_MAGICCLOSE; 417 418 data->wddev.info = &data->wdinfo; 419 data->wddev.ops = &watchdog_ops; 420 data->wddev.parent = parent; 421 data->wddev.timeout = 60; 422 data->wddev.min_timeout = 1; 423 data->wddev.max_timeout = 255 * 60; 424 if (nowayout) 425 set_bit(WDOG_NO_WAY_OUT, &data->wddev.status); 426 if (output_enable & SCH56XX_WDOG_OUTPUT_ENABLE) 427 set_bit(WDOG_ACTIVE, &data->wddev.status); 428 429 /* Since the watchdog uses a downcounter there is no register to read 430 the BIOS set timeout from (if any was set at all) -> 431 Choose a preset which will give us a 1 minute timeout */ 432 if (control & SCH56XX_WDOG_TIME_BASE_SEC) 433 data->watchdog_preset = 60; /* seconds */ 434 else 435 data->watchdog_preset = 1; /* minute */ 436 437 data->watchdog_control = control; 438 data->watchdog_output_enable = output_enable; 439 440 watchdog_set_drvdata(&data->wddev, data); 441 err = watchdog_register_device(&data->wddev); 442 if (err) { 443 pr_err("Registering watchdog chardev: %d\n", err); 444 kfree(data); 445 return NULL; 446 } 447 448 return data; 449 } 450 EXPORT_SYMBOL(sch56xx_watchdog_register); 451 452 void sch56xx_watchdog_unregister(struct sch56xx_watchdog_data *data) 453 { 454 watchdog_unregister_device(&data->wddev); 455 kfree(data); 456 } 457 EXPORT_SYMBOL(sch56xx_watchdog_unregister); 458 459 /* 460 * platform dev find, add and remove functions 461 */ 462 463 static int __init sch56xx_find(int sioaddr, const char **name) 464 { 465 u8 devid; 466 unsigned short address; 467 int err; 468 469 err = superio_enter(sioaddr); 470 if (err) 471 return err; 472 473 devid = superio_inb(sioaddr, SIO_REG_DEVID); 474 switch (devid) { 475 case SIO_SCH5627_ID: 476 *name = "sch5627"; 477 break; 478 case SIO_SCH5636_ID: 479 *name = "sch5636"; 480 break; 481 default: 482 pr_debug("Unsupported device id: 0x%02x\n", 483 (unsigned int)devid); 484 err = -ENODEV; 485 goto exit; 486 } 487 488 superio_select(sioaddr, SIO_SCH56XX_LD_EM); 489 490 if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) { 491 pr_warn("Device not activated\n"); 492 err = -ENODEV; 493 goto exit; 494 } 495 496 /* 497 * Warning the order of the low / high byte is the other way around 498 * as on most other superio devices!! 499 */ 500 address = superio_inb(sioaddr, SIO_REG_ADDR) | 501 superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8; 502 if (address == 0) { 503 pr_warn("Base address not set\n"); 504 err = -ENODEV; 505 goto exit; 506 } 507 err = address; 508 509 exit: 510 superio_exit(sioaddr); 511 return err; 512 } 513 514 static int __init sch56xx_device_add(int address, const char *name) 515 { 516 struct resource res = { 517 .start = address, 518 .end = address + REGION_LENGTH - 1, 519 .flags = IORESOURCE_IO, 520 }; 521 int err; 522 523 sch56xx_pdev = platform_device_alloc(name, address); 524 if (!sch56xx_pdev) 525 return -ENOMEM; 526 527 res.name = sch56xx_pdev->name; 528 err = acpi_check_resource_conflict(&res); 529 if (err) 530 goto exit_device_put; 531 532 err = platform_device_add_resources(sch56xx_pdev, &res, 1); 533 if (err) { 534 pr_err("Device resource addition failed\n"); 535 goto exit_device_put; 536 } 537 538 err = platform_device_add(sch56xx_pdev); 539 if (err) { 540 pr_err("Device addition failed\n"); 541 goto exit_device_put; 542 } 543 544 return 0; 545 546 exit_device_put: 547 platform_device_put(sch56xx_pdev); 548 549 return err; 550 } 551 552 static int __init sch56xx_init(void) 553 { 554 int address; 555 const char *name = NULL; 556 557 address = sch56xx_find(0x4e, &name); 558 if (address < 0) 559 address = sch56xx_find(0x2e, &name); 560 if (address < 0) 561 return address; 562 563 return sch56xx_device_add(address, name); 564 } 565 566 static void __exit sch56xx_exit(void) 567 { 568 platform_device_unregister(sch56xx_pdev); 569 } 570 571 MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code"); 572 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>"); 573 MODULE_LICENSE("GPL"); 574 575 module_init(sch56xx_init); 576 module_exit(sch56xx_exit); 577