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/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);