drivers/hwmon/sch56xx-common.c

   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/regmap.h>
  13 #include <linux/err.h>
  14 #include <linux/io.h>
  15 #include <linux/acpi.h>
  16 #include <linux/delay.h>
  17 #include <linux/fs.h>
  18 #include <linux/watchdog.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/slab.h>
  21 #include "sch56xx-common.h"
  22
  23 /* Insmod parameters */
  24 static bool nowayout = WATCHDOG_NOWAYOUT;
  25 module_param(nowayout, bool, 0);
  26 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  27         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  28
  29 #define SIO_SCH56XX_LD_EM       0x0C    /* Embedded uController Logical Dev */
  30 #define SIO_UNLOCK_KEY          0x55    /* Key to enable Super-I/O */
  31 #define SIO_LOCK_KEY            0xAA    /* Key to disable Super-I/O */
  32
  33 #define SIO_REG_LDSEL           0x07    /* Logical device select */
  34 #define SIO_REG_DEVID           0x20    /* Device ID */
  35 #define SIO_REG_ENABLE          0x30    /* Logical device enable */
  36 #define SIO_REG_ADDR            0x66    /* Logical device address (2 bytes) */
  37
  38 #define SIO_SCH5627_ID          0xC6    /* Chipset ID */
  39 #define SIO_SCH5636_ID          0xC7    /* Chipset ID */
  40
  41 #define REGION_LENGTH           10
  42
  43 #define SCH56XX_CMD_READ        0x02
  44 #define SCH56XX_CMD_WRITE       0x03
  45
  46 /* Watchdog registers */
  47 #define SCH56XX_REG_WDOG_PRESET         0x58B
  48 #define SCH56XX_REG_WDOG_CONTROL        0x58C
  49 #define SCH56XX_WDOG_TIME_BASE_SEC      0x01
  50 #define SCH56XX_REG_WDOG_OUTPUT_ENABLE  0x58E
  51 #define SCH56XX_WDOG_OUTPUT_ENABLE      0x02
  52
  53 struct sch56xx_watchdog_data {
  54         u16 addr;
  55         struct mutex *io_lock;
  56         struct watchdog_info wdinfo;
  57         struct watchdog_device wddev;
  58         u8 watchdog_preset;
  59         u8 watchdog_control;
  60         u8 watchdog_output_enable;
  61 };
  62
  63 struct sch56xx_bus_context {
  64         struct mutex *lock;     /* Used to serialize access to the mailbox registers */
  65         u16 addr;
  66 };
  67
  68 static struct platform_device *sch56xx_pdev;
  69
  70 /* Super I/O functions */
  71 static inline int superio_inb(int base, int reg)
  72 {
  73         outb(reg, base);
  74         return inb(base + 1);
  75 }
  76
  77 static inline int superio_enter(int base)
  78 {
  79         /* Don't step on other drivers' I/O space by accident */
  80         if (!request_muxed_region(base, 2, "sch56xx")) {
  81                 pr_err("I/O address 0x%04x already in use\n", base);
  82                 return -EBUSY;
  83         }
  84
  85         outb(SIO_UNLOCK_KEY, base);
  86
  87         return 0;
  88 }
  89
  90 static inline void superio_select(int base, int ld)
  91 {
  92         outb(SIO_REG_LDSEL, base);
  93         outb(ld, base + 1);
  94 }
  95
  96 static inline void superio_exit(int base)
  97 {
  98         outb(SIO_LOCK_KEY, base);
  99         release_region(base, 2);
 100 }
 101
 102 static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v)
 103 {
 104         u8 val;
 105         int i;
 106         /*
 107          * According to SMSC for the commands we use the maximum time for
 108          * the EM to respond is 15 ms, but testing shows in practice it
 109          * responds within 15-32 reads, so we first busy poll, and if
 110          * that fails sleep a bit and try again until we are way past
 111          * the 15 ms maximum response time.
 112          */
 113         const int max_busy_polls = 64;
 114         const int max_lazy_polls = 32;
 115
 116         /* (Optional) Write-Clear the EC to Host Mailbox Register */
 117         val = inb(addr + 1);
 118         outb(val, addr + 1);
 119
 120         /* Set Mailbox Address Pointer to first location in Region 1 */
 121         outb(0x00, addr + 2);
 122         outb(0x80, addr + 3);
 123
 124         /* Write Request Packet Header */
 125         outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */
 126         outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */
 127         outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */
 128
 129         /* Write Value field */
 130         if (cmd == SCH56XX_CMD_WRITE)
 131                 outb(v, addr + 4);
 132
 133         /* Write Address field */
 134         outb(reg & 0xff, addr + 6);
 135         outb(reg >> 8, addr + 7);
 136
 137         /* Execute the Random Access Command */
 138         outb(0x01, addr); /* Write 01h to the Host-to-EC register */
 139
 140         /* EM Interface Polling "Algorithm" */
 141         for (i = 0; i < max_busy_polls + max_lazy_polls; i++) {
 142                 if (i >= max_busy_polls)
 143                         usleep_range(1000, 2000);
 144                 /* Read Interrupt source Register */
 145                 val = inb(addr + 8);
 146                 /* Write Clear the interrupt source bits */
 147                 if (val)
 148                         outb(val, addr + 8);
 149                 /* Command Completed ? */
 150                 if (val & 0x01)
 151                         break;
 152         }
 153         if (i == max_busy_polls + max_lazy_polls) {
 154                 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
 155                        reg, 1);
 156                 return -EIO;
 157         }
 158
 159         /*
 160          * According to SMSC we may need to retry this, but sofar I've always
 161          * seen this succeed in 1 try.
 162          */
 163         for (i = 0; i < max_busy_polls; i++) {
 164                 /* Read EC-to-Host Register */
 165                 val = inb(addr + 1);
 166                 /* Command Completed ? */
 167                 if (val == 0x01)
 168                         break;
 169
 170                 if (i == 0)
 171                         pr_warn("EC reports: 0x%02x reading virtual register 0x%04hx\n",
 172                                 (unsigned int)val, reg);
 173         }
 174         if (i == max_busy_polls) {
 175                 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
 176                        reg, 2);
 177                 return -EIO;
 178         }
 179
 180         /*
 181          * According to the SMSC app note we should now do:
 182          *
 183          * Set Mailbox Address Pointer to first location in Region 1 *
 184          * outb(0x00, addr + 2);
 185          * outb(0x80, addr + 3);
 186          *
 187          * But if we do that things don't work, so let's not.
 188          */
 189
 190         /* Read Value field */
 191         if (cmd == SCH56XX_CMD_READ)
 192                 return inb(addr + 4);
 193
 194         return 0;
 195 }
 196
 197 int sch56xx_read_virtual_reg(u16 addr, u16 reg)
 198 {
 199         return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0);
 200 }
 201 EXPORT_SYMBOL(sch56xx_read_virtual_reg);
 202
 203 int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val)
 204 {
 205         return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val);
 206 }
 207 EXPORT_SYMBOL(sch56xx_write_virtual_reg);
 208
 209 int sch56xx_read_virtual_reg16(u16 addr, u16 reg)
 210 {
 211         int lsb, msb;
 212
 213         /* Read LSB first, this will cause the matching MSB to be latched */
 214         lsb = sch56xx_read_virtual_reg(addr, reg);
 215         if (lsb < 0)
 216                 return lsb;
 217
 218         msb = sch56xx_read_virtual_reg(addr, reg + 1);
 219         if (msb < 0)
 220                 return msb;
 221
 222         return lsb | (msb << 8);
 223 }
 224 EXPORT_SYMBOL(sch56xx_read_virtual_reg16);
 225
 226 int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg,
 227                                int high_nibble)
 228 {
 229         int msb, lsn;
 230
 231         /* Read MSB first, this will cause the matching LSN to be latched */
 232         msb = sch56xx_read_virtual_reg(addr, msb_reg);
 233         if (msb < 0)
 234                 return msb;
 235
 236         lsn = sch56xx_read_virtual_reg(addr, lsn_reg);
 237         if (lsn < 0)
 238                 return lsn;
 239
 240         if (high_nibble)
 241                 return (msb << 4) | (lsn >> 4);
 242         else
 243                 return (msb << 4) | (lsn & 0x0f);
 244 }
 245 EXPORT_SYMBOL(sch56xx_read_virtual_reg12);
 246
 247 /*
 248  * Regmap support
 249  */
 250
 251 int sch56xx_regmap_read16(struct regmap *map, unsigned int reg, unsigned int *val)
 252 {
 253         int lsb, msb, ret;
 254
 255         /* See sch56xx_read_virtual_reg16() */
 256         ret = regmap_read(map, reg, &lsb);
 257         if (ret < 0)
 258                 return ret;
 259
 260         ret = regmap_read(map, reg + 1, &msb);
 261         if (ret < 0)
 262                 return ret;
 263
 264         *val = lsb | (msb << 8);
 265
 266         return 0;
 267 }
 268 EXPORT_SYMBOL(sch56xx_regmap_read16);
 269
 270 int sch56xx_regmap_write16(struct regmap *map, unsigned int reg, unsigned int val)
 271 {
 272         int ret;
 273
 274         ret = regmap_write(map, reg, val & 0xff);
 275         if (ret < 0)
 276                 return ret;
 277
 278         return regmap_write(map, reg + 1, (val >> 8) & 0xff);
 279 }
 280 EXPORT_SYMBOL(sch56xx_regmap_write16);
 281
 282 static int sch56xx_reg_write(void *context, unsigned int reg, unsigned int val)
 283 {
 284         struct sch56xx_bus_context *bus = context;
 285         int ret;
 286
 287         mutex_lock(bus->lock);
 288         ret = sch56xx_write_virtual_reg(bus->addr, (u16)reg, (u8)val);
 289         mutex_unlock(bus->lock);
 290
 291         return ret;
 292 }
 293
 294 static int sch56xx_reg_read(void *context, unsigned int reg, unsigned int *val)
 295 {
 296         struct sch56xx_bus_context *bus = context;
 297         int ret;
 298
 299         mutex_lock(bus->lock);
 300         ret = sch56xx_read_virtual_reg(bus->addr, (u16)reg);
 301         mutex_unlock(bus->lock);
 302
 303         if (ret < 0)
 304                 return ret;
 305
 306         *val = ret;
 307
 308         return 0;
 309 }
 310
 311 static void sch56xx_free_context(void *context)
 312 {
 313         kfree(context);
 314 }
 315
 316 static const struct regmap_bus sch56xx_bus = {
 317         .reg_write = sch56xx_reg_write,
 318         .reg_read = sch56xx_reg_read,
 319         .free_context = sch56xx_free_context,
 320         .reg_format_endian_default = REGMAP_ENDIAN_LITTLE,
 321         .val_format_endian_default = REGMAP_ENDIAN_LITTLE,
 322 };
 323
 324 struct regmap *devm_regmap_init_sch56xx(struct device *dev, struct mutex *lock, u16 addr,
 325                                         const struct regmap_config *config)
 326 {
 327         struct sch56xx_bus_context *context;
 328         struct regmap *map;
 329
 330         if (config->reg_bits != 16 && config->val_bits != 8)
 331                 return ERR_PTR(-EOPNOTSUPP);
 332
 333         context = kzalloc(sizeof(*context), GFP_KERNEL);
 334         if (!context)
 335                 return ERR_PTR(-ENOMEM);
 336
 337         context->lock = lock;
 338         context->addr = addr;
 339
 340         map = devm_regmap_init(dev, &sch56xx_bus, context, config);
 341         if (IS_ERR(map))
 342                 kfree(context);
 343
 344         return map;
 345 }
 346 EXPORT_SYMBOL(devm_regmap_init_sch56xx);
 347
 348 /*
 349  * Watchdog routines
 350  */
 351
 352 static int watchdog_set_timeout(struct watchdog_device *wddev,
 353                                 unsigned int timeout)
 354 {
 355         struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
 356         unsigned int resolution;
 357         u8 control;
 358         int ret;
 359
 360         /* 1 second or 60 second resolution? */
 361         if (timeout <= 255)
 362                 resolution = 1;
 363         else
 364                 resolution = 60;
 365
 366         if (timeout < resolution || timeout > (resolution * 255))
 367                 return -EINVAL;
 368
 369         if (resolution == 1)
 370                 control = data->watchdog_control | SCH56XX_WDOG_TIME_BASE_SEC;
 371         else
 372                 control = data->watchdog_control & ~SCH56XX_WDOG_TIME_BASE_SEC;
 373
 374         if (data->watchdog_control != control) {
 375                 mutex_lock(data->io_lock);
 376                 ret = sch56xx_write_virtual_reg(data->addr,
 377                                                 SCH56XX_REG_WDOG_CONTROL,
 378                                                 control);
 379                 mutex_unlock(data->io_lock);
 380                 if (ret)
 381                         return ret;
 382
 383                 data->watchdog_control = control;
 384         }
 385
 386         /*
 387          * Remember new timeout value, but do not write as that (re)starts
 388          * the watchdog countdown.
 389          */
 390         data->watchdog_preset = DIV_ROUND_UP(timeout, resolution);
 391         wddev->timeout = data->watchdog_preset * resolution;
 392
 393         return 0;
 394 }
 395
 396 static int watchdog_start(struct watchdog_device *wddev)
 397 {
 398         struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
 399         int ret;
 400         u8 val;
 401
 402         /*
 403          * The sch56xx's watchdog cannot really be started / stopped
 404          * it is always running, but we can avoid the timer expiring
 405          * from causing a system reset by clearing the output enable bit.
 406          *
 407          * The sch56xx's watchdog will set the watchdog event bit, bit 0
 408          * of the second interrupt source register (at base-address + 9),
 409          * when the timer expires.
 410          *
 411          * This will only cause a system reset if the 0-1 flank happens when
 412          * output enable is true. Setting output enable after the flank will
 413          * not cause a reset, nor will the timer expiring a second time.
 414          * This means we must clear the watchdog event bit in case it is set.
 415          *
 416          * The timer may still be running (after a recent watchdog_stop) and
 417          * mere milliseconds away from expiring, so the timer must be reset
 418          * first!
 419          */
 420
 421         mutex_lock(data->io_lock);
 422
 423         /* 1. Reset the watchdog countdown counter */
 424         ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
 425                                         data->watchdog_preset);
 426         if (ret)
 427                 goto leave;
 428
 429         /* 2. Enable output */
 430         val = data->watchdog_output_enable | SCH56XX_WDOG_OUTPUT_ENABLE;
 431         ret = sch56xx_write_virtual_reg(data->addr,
 432                                         SCH56XX_REG_WDOG_OUTPUT_ENABLE, val);
 433         if (ret)
 434                 goto leave;
 435
 436         data->watchdog_output_enable = val;
 437
 438         /* 3. Clear the watchdog event bit if set */
 439         val = inb(data->addr + 9);
 440         if (val & 0x01)
 441                 outb(0x01, data->addr + 9);
 442
 443 leave:
 444         mutex_unlock(data->io_lock);
 445         return ret;
 446 }
 447
 448 static int watchdog_trigger(struct watchdog_device *wddev)
 449 {
 450         struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
 451         int ret;
 452
 453         /* Reset the watchdog countdown counter */
 454         mutex_lock(data->io_lock);
 455         ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
 456                                         data->watchdog_preset);
 457         mutex_unlock(data->io_lock);
 458
 459         return ret;
 460 }
 461
 462 static int watchdog_stop(struct watchdog_device *wddev)
 463 {
 464         struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
 465         int ret = 0;
 466         u8 val;
 467
 468         val = data->watchdog_output_enable & ~SCH56XX_WDOG_OUTPUT_ENABLE;
 469         mutex_lock(data->io_lock);
 470         ret = sch56xx_write_virtual_reg(data->addr,
 471                                         SCH56XX_REG_WDOG_OUTPUT_ENABLE, val);
 472         mutex_unlock(data->io_lock);
 473         if (ret)
 474                 return ret;
 475
 476         data->watchdog_output_enable = val;
 477         return 0;
 478 }
 479
 480 static const struct watchdog_ops watchdog_ops = {
 481         .owner          = THIS_MODULE,
 482         .start          = watchdog_start,
 483         .stop           = watchdog_stop,
 484         .ping           = watchdog_trigger,
 485         .set_timeout    = watchdog_set_timeout,
 486 };
 487
 488 void sch56xx_watchdog_register(struct device *parent, u16 addr, u32 revision,
 489                                struct mutex *io_lock, int check_enabled)
 490 {
 491         struct sch56xx_watchdog_data *data;
 492         int err, control, output_enable;
 493
 494         /* Cache the watchdog registers */
 495         mutex_lock(io_lock);
 496         control =
 497                 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_CONTROL);
 498         output_enable =
 499                 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE);
 500         mutex_unlock(io_lock);
 501
 502         if (control < 0)
 503                 return;
 504         if (output_enable < 0)
 505                 return;
 506         if (check_enabled && !(output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) {
 507                 pr_warn("Watchdog not enabled by BIOS, not registering\n");
 508                 return;
 509         }
 510
 511         data = devm_kzalloc(parent, sizeof(struct sch56xx_watchdog_data), GFP_KERNEL);
 512         if (!data)
 513                 return;
 514
 515         data->addr = addr;
 516         data->io_lock = io_lock;
 517
 518         strscpy(data->wdinfo.identity, "sch56xx watchdog", sizeof(data->wdinfo.identity));
 519         data->wdinfo.firmware_version = revision;
 520         data->wdinfo.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT;
 521         if (!nowayout)
 522                 data->wdinfo.options |= WDIOF_MAGICCLOSE;
 523
 524         data->wddev.info = &data->wdinfo;
 525         data->wddev.ops = &watchdog_ops;
 526         data->wddev.parent = parent;
 527         data->wddev.timeout = 60;
 528         data->wddev.min_timeout = 1;
 529         data->wddev.max_timeout = 255 * 60;
 530         watchdog_set_nowayout(&data->wddev, nowayout);
 531         if (output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)
 532                 set_bit(WDOG_HW_RUNNING, &data->wddev.status);
 533
 534         /* Since the watchdog uses a downcounter there is no register to read
 535            the BIOS set timeout from (if any was set at all) ->
 536            Choose a preset which will give us a 1 minute timeout */
 537         if (control & SCH56XX_WDOG_TIME_BASE_SEC)
 538                 data->watchdog_preset = 60; /* seconds */
 539         else
 540                 data->watchdog_preset = 1; /* minute */
 541
 542         data->watchdog_control = control;
 543         data->watchdog_output_enable = output_enable;
 544
 545         watchdog_set_drvdata(&data->wddev, data);
 546         err = devm_watchdog_register_device(parent, &data->wddev);
 547         if (err) {
 548                 pr_err("Registering watchdog chardev: %d\n", err);
 549                 devm_kfree(parent, data);
 550         }
 551 }
 552 EXPORT_SYMBOL(sch56xx_watchdog_register);
 553
 554 /*
 555  * platform dev find, add and remove functions
 556  */
 557
 558 static int __init sch56xx_find(int sioaddr, const char **name)
 559 {
 560         u8 devid;
 561         unsigned short address;
 562         int err;
 563
 564         err = superio_enter(sioaddr);
 565         if (err)
 566                 return err;
 567
 568         devid = superio_inb(sioaddr, SIO_REG_DEVID);
 569         switch (devid) {
 570         case SIO_SCH5627_ID:
 571                 *name = "sch5627";
 572                 break;
 573         case SIO_SCH5636_ID:
 574                 *name = "sch5636";
 575                 break;
 576         default:
 577                 pr_debug("Unsupported device id: 0x%02x\n",
 578                          (unsigned int)devid);
 579                 err = -ENODEV;
 580                 goto exit;
 581         }
 582
 583         superio_select(sioaddr, SIO_SCH56XX_LD_EM);
 584
 585         if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) {
 586                 pr_warn("Device not activated\n");
 587                 err = -ENODEV;
 588                 goto exit;
 589         }
 590
 591         /*
 592          * Warning the order of the low / high byte is the other way around
 593          * as on most other superio devices!!
 594          */
 595         address = superio_inb(sioaddr, SIO_REG_ADDR) |
 596                    superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8;
 597         if (address == 0) {
 598                 pr_warn("Base address not set\n");
 599                 err = -ENODEV;
 600                 goto exit;
 601         }
 602         err = address;
 603
 604 exit:
 605         superio_exit(sioaddr);
 606         return err;
 607 }
 608
 609 static int __init sch56xx_device_add(int address, const char *name)
 610 {
 611         struct resource res = {
 612                 .start  = address,
 613                 .end    = address + REGION_LENGTH - 1,
 614                 .name   = name,
 615                 .flags  = IORESOURCE_IO,
 616         };
 617         int err;
 618
 619         err = acpi_check_resource_conflict(&res);
 620         if (err)
 621                 return err;
 622
 623         sch56xx_pdev = platform_device_register_simple(name, -1, &res, 1);
 624
 625         return PTR_ERR_OR_ZERO(sch56xx_pdev);
 626 }
 627
 628 static int __init sch56xx_init(void)
 629 {
 630         int address;
 631         const char *name = NULL;
 632
 633         address = sch56xx_find(0x4e, &name);
 634         if (address < 0)
 635                 address = sch56xx_find(0x2e, &name);
 636         if (address < 0)
 637                 return address;
 638
 639         return sch56xx_device_add(address, name);
 640 }
 641
 642 static void __exit sch56xx_exit(void)
 643 {
 644         platform_device_unregister(sch56xx_pdev);
 645 }
 646
 647 MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
 648 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
 649 MODULE_LICENSE("GPL");
 650
 651 module_init(sch56xx_init);
 652 module_exit(sch56xx_exit);