linux/drivers/platform/x86/dell/dcdbas.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  dcdbas.c: Dell Systems Management Base Driver
   4 *
   5 *  The Dell Systems Management Base Driver provides a sysfs interface for
   6 *  systems management software to perform System Management Interrupts (SMIs)
   7 *  and Host Control Actions (power cycle or power off after OS shutdown) on
   8 *  Dell systems.
   9 *
  10 *  See Documentation/driver-api/dcdbas.rst for more information.
  11 *
  12 *  Copyright (C) 1995-2006 Dell Inc.
  13 */
  14
  15#include <linux/platform_device.h>
  16#include <linux/acpi.h>
  17#include <linux/dma-mapping.h>
  18#include <linux/dmi.h>
  19#include <linux/errno.h>
  20#include <linux/cpu.h>
  21#include <linux/gfp.h>
  22#include <linux/init.h>
  23#include <linux/io.h>
  24#include <linux/kernel.h>
  25#include <linux/mc146818rtc.h>
  26#include <linux/module.h>
  27#include <linux/reboot.h>
  28#include <linux/sched.h>
  29#include <linux/smp.h>
  30#include <linux/spinlock.h>
  31#include <linux/string.h>
  32#include <linux/types.h>
  33#include <linux/mutex.h>
  34
  35#include "dcdbas.h"
  36
  37#define DRIVER_NAME             "dcdbas"
  38#define DRIVER_VERSION          "5.6.0-3.4"
  39#define DRIVER_DESCRIPTION      "Dell Systems Management Base Driver"
  40
  41static struct platform_device *dcdbas_pdev;
  42
  43static u8 *smi_data_buf;
  44static dma_addr_t smi_data_buf_handle;
  45static unsigned long smi_data_buf_size;
  46static unsigned long max_smi_data_buf_size = MAX_SMI_DATA_BUF_SIZE;
  47static u32 smi_data_buf_phys_addr;
  48static DEFINE_MUTEX(smi_data_lock);
  49static u8 *bios_buffer;
  50
  51static unsigned int host_control_action;
  52static unsigned int host_control_smi_type;
  53static unsigned int host_control_on_shutdown;
  54
  55static bool wsmt_enabled;
  56
  57/**
  58 * smi_data_buf_free: free SMI data buffer
  59 */
  60static void smi_data_buf_free(void)
  61{
  62        if (!smi_data_buf || wsmt_enabled)
  63                return;
  64
  65        dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
  66                __func__, smi_data_buf_phys_addr, smi_data_buf_size);
  67
  68        dma_free_coherent(&dcdbas_pdev->dev, smi_data_buf_size, smi_data_buf,
  69                          smi_data_buf_handle);
  70        smi_data_buf = NULL;
  71        smi_data_buf_handle = 0;
  72        smi_data_buf_phys_addr = 0;
  73        smi_data_buf_size = 0;
  74}
  75
  76/**
  77 * smi_data_buf_realloc: grow SMI data buffer if needed
  78 */
  79static int smi_data_buf_realloc(unsigned long size)
  80{
  81        void *buf;
  82        dma_addr_t handle;
  83
  84        if (smi_data_buf_size >= size)
  85                return 0;
  86
  87        if (size > max_smi_data_buf_size)
  88                return -EINVAL;
  89
  90        /* new buffer is needed */
  91        buf = dma_alloc_coherent(&dcdbas_pdev->dev, size, &handle, GFP_KERNEL);
  92        if (!buf) {
  93                dev_dbg(&dcdbas_pdev->dev,
  94                        "%s: failed to allocate memory size %lu\n",
  95                        __func__, size);
  96                return -ENOMEM;
  97        }
  98        /* memory zeroed by dma_alloc_coherent */
  99
 100        if (smi_data_buf)
 101                memcpy(buf, smi_data_buf, smi_data_buf_size);
 102
 103        /* free any existing buffer */
 104        smi_data_buf_free();
 105
 106        /* set up new buffer for use */
 107        smi_data_buf = buf;
 108        smi_data_buf_handle = handle;
 109        smi_data_buf_phys_addr = (u32) virt_to_phys(buf);
 110        smi_data_buf_size = size;
 111
 112        dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
 113                __func__, smi_data_buf_phys_addr, smi_data_buf_size);
 114
 115        return 0;
 116}
 117
 118static ssize_t smi_data_buf_phys_addr_show(struct device *dev,
 119                                           struct device_attribute *attr,
 120                                           char *buf)
 121{
 122        return sprintf(buf, "%x\n", smi_data_buf_phys_addr);
 123}
 124
 125static ssize_t smi_data_buf_size_show(struct device *dev,
 126                                      struct device_attribute *attr,
 127                                      char *buf)
 128{
 129        return sprintf(buf, "%lu\n", smi_data_buf_size);
 130}
 131
 132static ssize_t smi_data_buf_size_store(struct device *dev,
 133                                       struct device_attribute *attr,
 134                                       const char *buf, size_t count)
 135{
 136        unsigned long buf_size;
 137        ssize_t ret;
 138
 139        buf_size = simple_strtoul(buf, NULL, 10);
 140
 141        /* make sure SMI data buffer is at least buf_size */
 142        mutex_lock(&smi_data_lock);
 143        ret = smi_data_buf_realloc(buf_size);
 144        mutex_unlock(&smi_data_lock);
 145        if (ret)
 146                return ret;
 147
 148        return count;
 149}
 150
 151static ssize_t smi_data_read(struct file *filp, struct kobject *kobj,
 152                             struct bin_attribute *bin_attr,
 153                             char *buf, loff_t pos, size_t count)
 154{
 155        ssize_t ret;
 156
 157        mutex_lock(&smi_data_lock);
 158        ret = memory_read_from_buffer(buf, count, &pos, smi_data_buf,
 159                                        smi_data_buf_size);
 160        mutex_unlock(&smi_data_lock);
 161        return ret;
 162}
 163
 164static ssize_t smi_data_write(struct file *filp, struct kobject *kobj,
 165                              struct bin_attribute *bin_attr,
 166                              char *buf, loff_t pos, size_t count)
 167{
 168        ssize_t ret;
 169
 170        if ((pos + count) > max_smi_data_buf_size)
 171                return -EINVAL;
 172
 173        mutex_lock(&smi_data_lock);
 174
 175        ret = smi_data_buf_realloc(pos + count);
 176        if (ret)
 177                goto out;
 178
 179        memcpy(smi_data_buf + pos, buf, count);
 180        ret = count;
 181out:
 182        mutex_unlock(&smi_data_lock);
 183        return ret;
 184}
 185
 186static ssize_t host_control_action_show(struct device *dev,
 187                                        struct device_attribute *attr,
 188                                        char *buf)
 189{
 190        return sprintf(buf, "%u\n", host_control_action);
 191}
 192
 193static ssize_t host_control_action_store(struct device *dev,
 194                                         struct device_attribute *attr,
 195                                         const char *buf, size_t count)
 196{
 197        ssize_t ret;
 198
 199        /* make sure buffer is available for host control command */
 200        mutex_lock(&smi_data_lock);
 201        ret = smi_data_buf_realloc(sizeof(struct apm_cmd));
 202        mutex_unlock(&smi_data_lock);
 203        if (ret)
 204                return ret;
 205
 206        host_control_action = simple_strtoul(buf, NULL, 10);
 207        return count;
 208}
 209
 210static ssize_t host_control_smi_type_show(struct device *dev,
 211                                          struct device_attribute *attr,
 212                                          char *buf)
 213{
 214        return sprintf(buf, "%u\n", host_control_smi_type);
 215}
 216
 217static ssize_t host_control_smi_type_store(struct device *dev,
 218                                           struct device_attribute *attr,
 219                                           const char *buf, size_t count)
 220{
 221        host_control_smi_type = simple_strtoul(buf, NULL, 10);
 222        return count;
 223}
 224
 225static ssize_t host_control_on_shutdown_show(struct device *dev,
 226                                             struct device_attribute *attr,
 227                                             char *buf)
 228{
 229        return sprintf(buf, "%u\n", host_control_on_shutdown);
 230}
 231
 232static ssize_t host_control_on_shutdown_store(struct device *dev,
 233                                              struct device_attribute *attr,
 234                                              const char *buf, size_t count)
 235{
 236        host_control_on_shutdown = simple_strtoul(buf, NULL, 10);
 237        return count;
 238}
 239
 240static int raise_smi(void *par)
 241{
 242        struct smi_cmd *smi_cmd = par;
 243
 244        if (smp_processor_id() != 0) {
 245                dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0\n",
 246                        __func__);
 247                return -EBUSY;
 248        }
 249
 250        /* generate SMI */
 251        /* inb to force posted write through and make SMI happen now */
 252        asm volatile (
 253                "outb %b0,%w1\n"
 254                "inb %w1"
 255                : /* no output args */
 256                : "a" (smi_cmd->command_code),
 257                  "d" (smi_cmd->command_address),
 258                  "b" (smi_cmd->ebx),
 259                  "c" (smi_cmd->ecx)
 260                : "memory"
 261        );
 262
 263        return 0;
 264}
 265/**
 266 * dcdbas_smi_request: generate SMI request
 267 *
 268 * Called with smi_data_lock.
 269 */
 270int dcdbas_smi_request(struct smi_cmd *smi_cmd)
 271{
 272        int ret;
 273
 274        if (smi_cmd->magic != SMI_CMD_MAGIC) {
 275                dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",
 276                         __func__);
 277                return -EBADR;
 278        }
 279
 280        /* SMI requires CPU 0 */
 281        get_online_cpus();
 282        ret = smp_call_on_cpu(0, raise_smi, smi_cmd, true);
 283        put_online_cpus();
 284
 285        return ret;
 286}
 287
 288/**
 289 * smi_request_store:
 290 *
 291 * The valid values are:
 292 * 0: zero SMI data buffer
 293 * 1: generate calling interface SMI
 294 * 2: generate raw SMI
 295 *
 296 * User application writes smi_cmd to smi_data before telling driver
 297 * to generate SMI.
 298 */
 299static ssize_t smi_request_store(struct device *dev,
 300                                 struct device_attribute *attr,
 301                                 const char *buf, size_t count)
 302{
 303        struct smi_cmd *smi_cmd;
 304        unsigned long val = simple_strtoul(buf, NULL, 10);
 305        ssize_t ret;
 306
 307        mutex_lock(&smi_data_lock);
 308
 309        if (smi_data_buf_size < sizeof(struct smi_cmd)) {
 310                ret = -ENODEV;
 311                goto out;
 312        }
 313        smi_cmd = (struct smi_cmd *)smi_data_buf;
 314
 315        switch (val) {
 316        case 2:
 317                /* Raw SMI */
 318                ret = dcdbas_smi_request(smi_cmd);
 319                if (!ret)
 320                        ret = count;
 321                break;
 322        case 1:
 323                /*
 324                 * Calling Interface SMI
 325                 *
 326                 * Provide physical address of command buffer field within
 327                 * the struct smi_cmd to BIOS.
 328                 *
 329                 * Because the address that smi_cmd (smi_data_buf) points to
 330                 * will be from memremap() of a non-memory address if WSMT
 331                 * is present, we can't use virt_to_phys() on smi_cmd, so
 332                 * we have to use the physical address that was saved when
 333                 * the virtual address for smi_cmd was received.
 334                 */
 335                smi_cmd->ebx = smi_data_buf_phys_addr +
 336                                offsetof(struct smi_cmd, command_buffer);
 337                ret = dcdbas_smi_request(smi_cmd);
 338                if (!ret)
 339                        ret = count;
 340                break;
 341        case 0:
 342                memset(smi_data_buf, 0, smi_data_buf_size);
 343                ret = count;
 344                break;
 345        default:
 346                ret = -EINVAL;
 347                break;
 348        }
 349
 350out:
 351        mutex_unlock(&smi_data_lock);
 352        return ret;
 353}
 354EXPORT_SYMBOL(dcdbas_smi_request);
 355
 356/**
 357 * host_control_smi: generate host control SMI
 358 *
 359 * Caller must set up the host control command in smi_data_buf.
 360 */
 361static int host_control_smi(void)
 362{
 363        struct apm_cmd *apm_cmd;
 364        u8 *data;
 365        unsigned long flags;
 366        u32 num_ticks;
 367        s8 cmd_status;
 368        u8 index;
 369
 370        apm_cmd = (struct apm_cmd *)smi_data_buf;
 371        apm_cmd->status = ESM_STATUS_CMD_UNSUCCESSFUL;
 372
 373        switch (host_control_smi_type) {
 374        case HC_SMITYPE_TYPE1:
 375                spin_lock_irqsave(&rtc_lock, flags);
 376                /* write SMI data buffer physical address */
 377                data = (u8 *)&smi_data_buf_phys_addr;
 378                for (index = PE1300_CMOS_CMD_STRUCT_PTR;
 379                     index < (PE1300_CMOS_CMD_STRUCT_PTR + 4);
 380                     index++, data++) {
 381                        outb(index,
 382                             (CMOS_BASE_PORT + CMOS_PAGE2_INDEX_PORT_PIIX4));
 383                        outb(*data,
 384                             (CMOS_BASE_PORT + CMOS_PAGE2_DATA_PORT_PIIX4));
 385                }
 386
 387                /* first set status to -1 as called by spec */
 388                cmd_status = ESM_STATUS_CMD_UNSUCCESSFUL;
 389                outb((u8) cmd_status, PCAT_APM_STATUS_PORT);
 390
 391                /* generate SMM call */
 392                outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
 393                spin_unlock_irqrestore(&rtc_lock, flags);
 394
 395                /* wait a few to see if it executed */
 396                num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
 397                while ((s8)inb(PCAT_APM_STATUS_PORT) == ESM_STATUS_CMD_UNSUCCESSFUL) {
 398                        num_ticks--;
 399                        if (num_ticks == EXPIRED_TIMER)
 400                                return -ETIME;
 401                }
 402                break;
 403
 404        case HC_SMITYPE_TYPE2:
 405        case HC_SMITYPE_TYPE3:
 406                spin_lock_irqsave(&rtc_lock, flags);
 407                /* write SMI data buffer physical address */
 408                data = (u8 *)&smi_data_buf_phys_addr;
 409                for (index = PE1400_CMOS_CMD_STRUCT_PTR;
 410                     index < (PE1400_CMOS_CMD_STRUCT_PTR + 4);
 411                     index++, data++) {
 412                        outb(index, (CMOS_BASE_PORT + CMOS_PAGE1_INDEX_PORT));
 413                        outb(*data, (CMOS_BASE_PORT + CMOS_PAGE1_DATA_PORT));
 414                }
 415
 416                /* generate SMM call */
 417                if (host_control_smi_type == HC_SMITYPE_TYPE3)
 418                        outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
 419                else
 420                        outb(ESM_APM_CMD, PE1400_APM_CONTROL_PORT);
 421
 422                /* restore RTC index pointer since it was written to above */
 423                CMOS_READ(RTC_REG_C);
 424                spin_unlock_irqrestore(&rtc_lock, flags);
 425
 426                /* read control port back to serialize write */
 427                cmd_status = inb(PE1400_APM_CONTROL_PORT);
 428
 429                /* wait a few to see if it executed */
 430                num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
 431                while (apm_cmd->status == ESM_STATUS_CMD_UNSUCCESSFUL) {
 432                        num_ticks--;
 433                        if (num_ticks == EXPIRED_TIMER)
 434                                return -ETIME;
 435                }
 436                break;
 437
 438        default:
 439                dev_dbg(&dcdbas_pdev->dev, "%s: invalid SMI type %u\n",
 440                        __func__, host_control_smi_type);
 441                return -ENOSYS;
 442        }
 443
 444        return 0;
 445}
 446
 447/**
 448 * dcdbas_host_control: initiate host control
 449 *
 450 * This function is called by the driver after the system has
 451 * finished shutting down if the user application specified a
 452 * host control action to perform on shutdown.  It is safe to
 453 * use smi_data_buf at this point because the system has finished
 454 * shutting down and no userspace apps are running.
 455 */
 456static void dcdbas_host_control(void)
 457{
 458        struct apm_cmd *apm_cmd;
 459        u8 action;
 460
 461        if (host_control_action == HC_ACTION_NONE)
 462                return;
 463
 464        action = host_control_action;
 465        host_control_action = HC_ACTION_NONE;
 466
 467        if (!smi_data_buf) {
 468                dev_dbg(&dcdbas_pdev->dev, "%s: no SMI buffer\n", __func__);
 469                return;
 470        }
 471
 472        if (smi_data_buf_size < sizeof(struct apm_cmd)) {
 473                dev_dbg(&dcdbas_pdev->dev, "%s: SMI buffer too small\n",
 474                        __func__);
 475                return;
 476        }
 477
 478        apm_cmd = (struct apm_cmd *)smi_data_buf;
 479
 480        /* power off takes precedence */
 481        if (action & HC_ACTION_HOST_CONTROL_POWEROFF) {
 482                apm_cmd->command = ESM_APM_POWER_CYCLE;
 483                apm_cmd->reserved = 0;
 484                *((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 0;
 485                host_control_smi();
 486        } else if (action & HC_ACTION_HOST_CONTROL_POWERCYCLE) {
 487                apm_cmd->command = ESM_APM_POWER_CYCLE;
 488                apm_cmd->reserved = 0;
 489                *((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 20;
 490                host_control_smi();
 491        }
 492}
 493
 494/* WSMT */
 495
 496static u8 checksum(u8 *buffer, u8 length)
 497{
 498        u8 sum = 0;
 499        u8 *end = buffer + length;
 500
 501        while (buffer < end)
 502                sum += *buffer++;
 503        return sum;
 504}
 505
 506static inline struct smm_eps_table *check_eps_table(u8 *addr)
 507{
 508        struct smm_eps_table *eps = (struct smm_eps_table *)addr;
 509
 510        if (strncmp(eps->smm_comm_buff_anchor, SMM_EPS_SIG, 4) != 0)
 511                return NULL;
 512
 513        if (checksum(addr, eps->length) != 0)
 514                return NULL;
 515
 516        return eps;
 517}
 518
 519static int dcdbas_check_wsmt(void)
 520{
 521        const struct dmi_device *dev = NULL;
 522        struct acpi_table_wsmt *wsmt = NULL;
 523        struct smm_eps_table *eps = NULL;
 524        u64 bios_buf_paddr;
 525        u64 remap_size;
 526        u8 *addr;
 527
 528        acpi_get_table(ACPI_SIG_WSMT, 0, (struct acpi_table_header **)&wsmt);
 529        if (!wsmt)
 530                return 0;
 531
 532        /* Check if WSMT ACPI table shows that protection is enabled */
 533        if (!(wsmt->protection_flags & ACPI_WSMT_FIXED_COMM_BUFFERS) ||
 534            !(wsmt->protection_flags & ACPI_WSMT_COMM_BUFFER_NESTED_PTR_PROTECTION))
 535                return 0;
 536
 537        /*
 538         * BIOS could provide the address/size of the protected buffer
 539         * in an SMBIOS string or in an EPS structure in 0xFxxxx.
 540         */
 541
 542        /* Check SMBIOS for buffer address */
 543        while ((dev = dmi_find_device(DMI_DEV_TYPE_OEM_STRING, NULL, dev)))
 544                if (sscanf(dev->name, "30[%16llx;%8llx]", &bios_buf_paddr,
 545                    &remap_size) == 2)
 546                        goto remap;
 547
 548        /* Scan for EPS (entry point structure) */
 549        for (addr = (u8 *)__va(0xf0000);
 550             addr < (u8 *)__va(0x100000 - sizeof(struct smm_eps_table));
 551             addr += 16) {
 552                eps = check_eps_table(addr);
 553                if (eps)
 554                        break;
 555        }
 556
 557        if (!eps) {
 558                dev_dbg(&dcdbas_pdev->dev, "found WSMT, but no firmware buffer found\n");
 559                return -ENODEV;
 560        }
 561        bios_buf_paddr = eps->smm_comm_buff_addr;
 562        remap_size = eps->num_of_4k_pages * PAGE_SIZE;
 563
 564remap:
 565        /*
 566         * Get physical address of buffer and map to virtual address.
 567         * Table gives size in 4K pages, regardless of actual system page size.
 568         */
 569        if (upper_32_bits(bios_buf_paddr + 8)) {
 570                dev_warn(&dcdbas_pdev->dev, "found WSMT, but buffer address is above 4GB\n");
 571                return -EINVAL;
 572        }
 573        /*
 574         * Limit remap size to MAX_SMI_DATA_BUF_SIZE + 8 (since the first 8
 575         * bytes are used for a semaphore, not the data buffer itself).
 576         */
 577        if (remap_size > MAX_SMI_DATA_BUF_SIZE + 8)
 578                remap_size = MAX_SMI_DATA_BUF_SIZE + 8;
 579
 580        bios_buffer = memremap(bios_buf_paddr, remap_size, MEMREMAP_WB);
 581        if (!bios_buffer) {
 582                dev_warn(&dcdbas_pdev->dev, "found WSMT, but failed to map buffer\n");
 583                return -ENOMEM;
 584        }
 585
 586        /* First 8 bytes is for a semaphore, not part of the smi_data_buf */
 587        smi_data_buf_phys_addr = bios_buf_paddr + 8;
 588        smi_data_buf = bios_buffer + 8;
 589        smi_data_buf_size = remap_size - 8;
 590        max_smi_data_buf_size = smi_data_buf_size;
 591        wsmt_enabled = true;
 592        dev_info(&dcdbas_pdev->dev,
 593                 "WSMT found, using firmware-provided SMI buffer.\n");
 594        return 1;
 595}
 596
 597/**
 598 * dcdbas_reboot_notify: handle reboot notification for host control
 599 */
 600static int dcdbas_reboot_notify(struct notifier_block *nb, unsigned long code,
 601                                void *unused)
 602{
 603        switch (code) {
 604        case SYS_DOWN:
 605        case SYS_HALT:
 606        case SYS_POWER_OFF:
 607                if (host_control_on_shutdown) {
 608                        /* firmware is going to perform host control action */
 609                        printk(KERN_WARNING "Please wait for shutdown "
 610                               "action to complete...\n");
 611                        dcdbas_host_control();
 612                }
 613                break;
 614        }
 615
 616        return NOTIFY_DONE;
 617}
 618
 619static struct notifier_block dcdbas_reboot_nb = {
 620        .notifier_call = dcdbas_reboot_notify,
 621        .next = NULL,
 622        .priority = INT_MIN
 623};
 624
 625static DCDBAS_BIN_ATTR_RW(smi_data);
 626
 627static struct bin_attribute *dcdbas_bin_attrs[] = {
 628        &bin_attr_smi_data,
 629        NULL
 630};
 631
 632static DCDBAS_DEV_ATTR_RW(smi_data_buf_size);
 633static DCDBAS_DEV_ATTR_RO(smi_data_buf_phys_addr);
 634static DCDBAS_DEV_ATTR_WO(smi_request);
 635static DCDBAS_DEV_ATTR_RW(host_control_action);
 636static DCDBAS_DEV_ATTR_RW(host_control_smi_type);
 637static DCDBAS_DEV_ATTR_RW(host_control_on_shutdown);
 638
 639static struct attribute *dcdbas_dev_attrs[] = {
 640        &dev_attr_smi_data_buf_size.attr,
 641        &dev_attr_smi_data_buf_phys_addr.attr,
 642        &dev_attr_smi_request.attr,
 643        &dev_attr_host_control_action.attr,
 644        &dev_attr_host_control_smi_type.attr,
 645        &dev_attr_host_control_on_shutdown.attr,
 646        NULL
 647};
 648
 649static const struct attribute_group dcdbas_attr_group = {
 650        .attrs = dcdbas_dev_attrs,
 651        .bin_attrs = dcdbas_bin_attrs,
 652};
 653
 654static int dcdbas_probe(struct platform_device *dev)
 655{
 656        int error;
 657
 658        host_control_action = HC_ACTION_NONE;
 659        host_control_smi_type = HC_SMITYPE_NONE;
 660
 661        dcdbas_pdev = dev;
 662
 663        /* Check if ACPI WSMT table specifies protected SMI buffer address */
 664        error = dcdbas_check_wsmt();
 665        if (error < 0)
 666                return error;
 667
 668        /*
 669         * BIOS SMI calls require buffer addresses be in 32-bit address space.
 670         * This is done by setting the DMA mask below.
 671         */
 672        error = dma_set_coherent_mask(&dcdbas_pdev->dev, DMA_BIT_MASK(32));
 673        if (error)
 674                return error;
 675
 676        error = sysfs_create_group(&dev->dev.kobj, &dcdbas_attr_group);
 677        if (error)
 678                return error;
 679
 680        register_reboot_notifier(&dcdbas_reboot_nb);
 681
 682        dev_info(&dev->dev, "%s (version %s)\n",
 683                 DRIVER_DESCRIPTION, DRIVER_VERSION);
 684
 685        return 0;
 686}
 687
 688static int dcdbas_remove(struct platform_device *dev)
 689{
 690        unregister_reboot_notifier(&dcdbas_reboot_nb);
 691        sysfs_remove_group(&dev->dev.kobj, &dcdbas_attr_group);
 692
 693        return 0;
 694}
 695
 696static struct platform_driver dcdbas_driver = {
 697        .driver         = {
 698                .name   = DRIVER_NAME,
 699        },
 700        .probe          = dcdbas_probe,
 701        .remove         = dcdbas_remove,
 702};
 703
 704static const struct platform_device_info dcdbas_dev_info __initconst = {
 705        .name           = DRIVER_NAME,
 706        .id             = -1,
 707        .dma_mask       = DMA_BIT_MASK(32),
 708};
 709
 710static struct platform_device *dcdbas_pdev_reg;
 711
 712/**
 713 * dcdbas_init: initialize driver
 714 */
 715static int __init dcdbas_init(void)
 716{
 717        int error;
 718
 719        error = platform_driver_register(&dcdbas_driver);
 720        if (error)
 721                return error;
 722
 723        dcdbas_pdev_reg = platform_device_register_full(&dcdbas_dev_info);
 724        if (IS_ERR(dcdbas_pdev_reg)) {
 725                error = PTR_ERR(dcdbas_pdev_reg);
 726                goto err_unregister_driver;
 727        }
 728
 729        return 0;
 730
 731 err_unregister_driver:
 732        platform_driver_unregister(&dcdbas_driver);
 733        return error;
 734}
 735
 736/**
 737 * dcdbas_exit: perform driver cleanup
 738 */
 739static void __exit dcdbas_exit(void)
 740{
 741        /*
 742         * make sure functions that use dcdbas_pdev are called
 743         * before platform_device_unregister
 744         */
 745        unregister_reboot_notifier(&dcdbas_reboot_nb);
 746
 747        /*
 748         * We have to free the buffer here instead of dcdbas_remove
 749         * because only in module exit function we can be sure that
 750         * all sysfs attributes belonging to this module have been
 751         * released.
 752         */
 753        if (dcdbas_pdev)
 754                smi_data_buf_free();
 755        if (bios_buffer)
 756                memunmap(bios_buffer);
 757        platform_device_unregister(dcdbas_pdev_reg);
 758        platform_driver_unregister(&dcdbas_driver);
 759}
 760
 761subsys_initcall_sync(dcdbas_init);
 762module_exit(dcdbas_exit);
 763
 764MODULE_DESCRIPTION(DRIVER_DESCRIPTION " (version " DRIVER_VERSION ")");
 765MODULE_VERSION(DRIVER_VERSION);
 766MODULE_AUTHOR("Dell Inc.");
 767MODULE_LICENSE("GPL");
 768/* Any System or BIOS claiming to be by Dell */
 769MODULE_ALIAS("dmi:*:[bs]vnD[Ee][Ll][Ll]*:*");
 770