linux/drivers/hwmon/sch56xx-common.c
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   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 */
  38static int nowayout = WATCHDOG_NOWAYOUT;
  39module_param(nowayout, int, 0);
  40MODULE_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
  67struct 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
  78static struct platform_device *sch56xx_pdev;
  79
  80/* Super I/O functions */
  81static inline int superio_inb(int base, int reg)
  82{
  83        outb(reg, base);
  84        return inb(base + 1);
  85}
  86
  87static 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
 100static inline void superio_select(int base, int ld)
 101{
 102        outb(SIO_REG_LDSEL, base);
 103        outb(ld, base + 1);
 104}
 105
 106static inline void superio_exit(int base)
 107{
 108        outb(SIO_LOCK_KEY, base);
 109        release_region(base, 2);
 110}
 111
 112static 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
 207int sch56xx_read_virtual_reg(u16 addr, u16 reg)
 208{
 209        return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0);
 210}
 211EXPORT_SYMBOL(sch56xx_read_virtual_reg);
 212
 213int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val)
 214{
 215        return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val);
 216}
 217EXPORT_SYMBOL(sch56xx_write_virtual_reg);
 218
 219int 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}
 234EXPORT_SYMBOL(sch56xx_read_virtual_reg16);
 235
 236int 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}
 255EXPORT_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 */
 263static 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
 270static 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
 314static 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
 361leave:
 362        mutex_unlock(data->io_lock);
 363        return ret;
 364}
 365
 366static 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
 380static 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
 398static 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
 405static 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
 412static 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
 422struct 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}
 492EXPORT_SYMBOL(sch56xx_watchdog_register);
 493
 494void 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}
 500EXPORT_SYMBOL(sch56xx_watchdog_unregister);
 501
 502/*
 503 * platform dev find, add and remove functions
 504 */
 505
 506static 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
 552exit:
 553        superio_exit(sioaddr);
 554        return err;
 555}
 556
 557static 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
 589exit_device_put:
 590        platform_device_put(sch56xx_pdev);
 591
 592        return err;
 593}
 594
 595static 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
 609static void __exit sch56xx_exit(void)
 610{
 611        platform_device_unregister(sch56xx_pdev);
 612}
 613
 614MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
 615MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
 616MODULE_LICENSE("GPL");
 617
 618module_init(sch56xx_init);
 619module_exit(sch56xx_exit);
 620
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