drivers/platform/x86/dcdbas.c

   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
  41 static struct platform_device *dcdbas_pdev;
  42
  43 static u8 *smi_data_buf;
  44 static dma_addr_t smi_data_buf_handle;
  45 static unsigned long smi_data_buf_size;
  46 static unsigned long max_smi_data_buf_size = MAX_SMI_DATA_BUF_SIZE;
  47 static u32 smi_data_buf_phys_addr;
  48 static DEFINE_MUTEX(smi_data_lock);
  49 static u8 *bios_buffer;
  50
  51 static unsigned int host_control_action;
  52 static unsigned int host_control_smi_type;
  53 static unsigned int host_control_on_shutdown;
  54
  55 static bool wsmt_enabled;
  56
  57 /**
  58  * smi_data_buf_free: free SMI data buffer
  59  */
  60 static 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  */
  79 static 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
 118 static 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
 125 static 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
 132 static 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
 151 static 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
 164 static 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;
 181 out:
 182         mutex_unlock(&smi_data_lock);
 183         return ret;
 184 }
 185
 186 static 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
 193 static 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
 210 static 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
 217 static 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
 225 static 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
 232 static 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
 240 static 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  */
 270 int 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  */
 299 static 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
 350 out:
 351         mutex_unlock(&smi_data_lock);
 352         return ret;
 353 }
 354 EXPORT_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  */
 361 static 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 ((cmd_status = inb(PCAT_APM_STATUS_PORT))
 398                        == ESM_STATUS_CMD_UNSUCCESSFUL) {
 399                         num_ticks--;
 400                         if (num_ticks == EXPIRED_TIMER)
 401                                 return -ETIME;
 402                 }
 403                 break;
 404
 405         case HC_SMITYPE_TYPE2:
 406         case HC_SMITYPE_TYPE3:
 407                 spin_lock_irqsave(&rtc_lock, flags);
 408                 /* write SMI data buffer physical address */
 409                 data = (u8 *)&smi_data_buf_phys_addr;
 410                 for (index = PE1400_CMOS_CMD_STRUCT_PTR;
 411                      index < (PE1400_CMOS_CMD_STRUCT_PTR + 4);
 412                      index++, data++) {
 413                         outb(index, (CMOS_BASE_PORT + CMOS_PAGE1_INDEX_PORT));
 414                         outb(*data, (CMOS_BASE_PORT + CMOS_PAGE1_DATA_PORT));
 415                 }
 416
 417                 /* generate SMM call */
 418                 if (host_control_smi_type == HC_SMITYPE_TYPE3)
 419                         outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
 420                 else
 421                         outb(ESM_APM_CMD, PE1400_APM_CONTROL_PORT);
 422
 423                 /* restore RTC index pointer since it was written to above */
 424                 CMOS_READ(RTC_REG_C);
 425                 spin_unlock_irqrestore(&rtc_lock, flags);
 426
 427                 /* read control port back to serialize write */
 428                 cmd_status = inb(PE1400_APM_CONTROL_PORT);
 429
 430                 /* wait a few to see if it executed */
 431                 num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
 432                 while (apm_cmd->status == ESM_STATUS_CMD_UNSUCCESSFUL) {
 433                         num_ticks--;
 434                         if (num_ticks == EXPIRED_TIMER)
 435                                 return -ETIME;
 436                 }
 437                 break;
 438
 439         default:
 440                 dev_dbg(&dcdbas_pdev->dev, "%s: invalid SMI type %u\n",
 441                         __func__, host_control_smi_type);
 442                 return -ENOSYS;
 443         }
 444
 445         return 0;
 446 }
 447
 448 /**
 449  * dcdbas_host_control: initiate host control
 450  *
 451  * This function is called by the driver after the system has
 452  * finished shutting down if the user application specified a
 453  * host control action to perform on shutdown.  It is safe to
 454  * use smi_data_buf at this point because the system has finished
 455  * shutting down and no userspace apps are running.
 456  */
 457 static void dcdbas_host_control(void)
 458 {
 459         struct apm_cmd *apm_cmd;
 460         u8 action;
 461
 462         if (host_control_action == HC_ACTION_NONE)
 463                 return;
 464
 465         action = host_control_action;
 466         host_control_action = HC_ACTION_NONE;
 467
 468         if (!smi_data_buf) {
 469                 dev_dbg(&dcdbas_pdev->dev, "%s: no SMI buffer\n", __func__);
 470                 return;
 471         }
 472
 473         if (smi_data_buf_size < sizeof(struct apm_cmd)) {
 474                 dev_dbg(&dcdbas_pdev->dev, "%s: SMI buffer too small\n",
 475                         __func__);
 476                 return;
 477         }
 478
 479         apm_cmd = (struct apm_cmd *)smi_data_buf;
 480
 481         /* power off takes precedence */
 482         if (action & HC_ACTION_HOST_CONTROL_POWEROFF) {
 483                 apm_cmd->command = ESM_APM_POWER_CYCLE;
 484                 apm_cmd->reserved = 0;
 485                 *((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 0;
 486                 host_control_smi();
 487         } else if (action & HC_ACTION_HOST_CONTROL_POWERCYCLE) {
 488                 apm_cmd->command = ESM_APM_POWER_CYCLE;
 489                 apm_cmd->reserved = 0;
 490                 *((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 20;
 491                 host_control_smi();
 492         }
 493 }
 494
 495 /* WSMT */
 496
 497 static u8 checksum(u8 *buffer, u8 length)
 498 {
 499         u8 sum = 0;
 500         u8 *end = buffer + length;
 501
 502         while (buffer < end)
 503                 sum += *buffer++;
 504         return sum;
 505 }
 506
 507 static inline struct smm_eps_table *check_eps_table(u8 *addr)
 508 {
 509         struct smm_eps_table *eps = (struct smm_eps_table *)addr;
 510
 511         if (strncmp(eps->smm_comm_buff_anchor, SMM_EPS_SIG, 4) != 0)
 512                 return NULL;
 513
 514         if (checksum(addr, eps->length) != 0)
 515                 return NULL;
 516
 517         return eps;
 518 }
 519
 520 static int dcdbas_check_wsmt(void)
 521 {
 522         const struct dmi_device *dev = NULL;
 523         struct acpi_table_wsmt *wsmt = NULL;
 524         struct smm_eps_table *eps = NULL;
 525         u64 bios_buf_paddr;
 526         u64 remap_size;
 527         u8 *addr;
 528
 529         acpi_get_table(ACPI_SIG_WSMT, 0, (struct acpi_table_header **)&wsmt);
 530         if (!wsmt)
 531                 return 0;
 532
 533         /* Check if WSMT ACPI table shows that protection is enabled */
 534         if (!(wsmt->protection_flags & ACPI_WSMT_FIXED_COMM_BUFFERS) ||
 535             !(wsmt->protection_flags & ACPI_WSMT_COMM_BUFFER_NESTED_PTR_PROTECTION))
 536                 return 0;
 537
 538         /*
 539          * BIOS could provide the address/size of the protected buffer
 540          * in an SMBIOS string or in an EPS structure in 0xFxxxx.
 541          */
 542
 543         /* Check SMBIOS for buffer address */
 544         while ((dev = dmi_find_device(DMI_DEV_TYPE_OEM_STRING, NULL, dev)))
 545                 if (sscanf(dev->name, "30[%16llx;%8llx]", &bios_buf_paddr,
 546                     &remap_size) == 2)
 547                         goto remap;
 548
 549         /* Scan for EPS (entry point structure) */
 550         for (addr = (u8 *)__va(0xf0000);
 551              addr < (u8 *)__va(0x100000 - sizeof(struct smm_eps_table));
 552              addr += 16) {
 553                 eps = check_eps_table(addr);
 554                 if (eps)
 555                         break;
 556         }
 557
 558         if (!eps) {
 559                 dev_dbg(&dcdbas_pdev->dev, "found WSMT, but no firmware buffer found\n");
 560                 return -ENODEV;
 561         }
 562         bios_buf_paddr = eps->smm_comm_buff_addr;
 563         remap_size = eps->num_of_4k_pages * PAGE_SIZE;
 564
 565 remap:
 566         /*
 567          * Get physical address of buffer and map to virtual address.
 568          * Table gives size in 4K pages, regardless of actual system page size.
 569          */
 570         if (upper_32_bits(bios_buf_paddr + 8)) {
 571                 dev_warn(&dcdbas_pdev->dev, "found WSMT, but buffer address is above 4GB\n");
 572                 return -EINVAL;
 573         }
 574         /*
 575          * Limit remap size to MAX_SMI_DATA_BUF_SIZE + 8 (since the first 8
 576          * bytes are used for a semaphore, not the data buffer itself).
 577          */
 578         if (remap_size > MAX_SMI_DATA_BUF_SIZE + 8)
 579                 remap_size = MAX_SMI_DATA_BUF_SIZE + 8;
 580
 581         bios_buffer = memremap(bios_buf_paddr, remap_size, MEMREMAP_WB);
 582         if (!bios_buffer) {
 583                 dev_warn(&dcdbas_pdev->dev, "found WSMT, but failed to map buffer\n");
 584                 return -ENOMEM;
 585         }
 586
 587         /* First 8 bytes is for a semaphore, not part of the smi_data_buf */
 588         smi_data_buf_phys_addr = bios_buf_paddr + 8;
 589         smi_data_buf = bios_buffer + 8;
 590         smi_data_buf_size = remap_size - 8;
 591         max_smi_data_buf_size = smi_data_buf_size;
 592         wsmt_enabled = true;
 593         dev_info(&dcdbas_pdev->dev,
 594                  "WSMT found, using firmware-provided SMI buffer.\n");
 595         return 1;
 596 }
 597
 598 /**
 599  * dcdbas_reboot_notify: handle reboot notification for host control
 600  */
 601 static int dcdbas_reboot_notify(struct notifier_block *nb, unsigned long code,
 602                                 void *unused)
 603 {
 604         switch (code) {
 605         case SYS_DOWN:
 606         case SYS_HALT:
 607         case SYS_POWER_OFF:
 608                 if (host_control_on_shutdown) {
 609                         /* firmware is going to perform host control action */
 610                         printk(KERN_WARNING "Please wait for shutdown "
 611                                "action to complete...\n");
 612                         dcdbas_host_control();
 613                 }
 614                 break;
 615         }
 616
 617         return NOTIFY_DONE;
 618 }
 619
 620 static struct notifier_block dcdbas_reboot_nb = {
 621         .notifier_call = dcdbas_reboot_notify,
 622         .next = NULL,
 623         .priority = INT_MIN
 624 };
 625
 626 static DCDBAS_BIN_ATTR_RW(smi_data);
 627
 628 static struct bin_attribute *dcdbas_bin_attrs[] = {
 629         &bin_attr_smi_data,
 630         NULL
 631 };
 632
 633 static DCDBAS_DEV_ATTR_RW(smi_data_buf_size);
 634 static DCDBAS_DEV_ATTR_RO(smi_data_buf_phys_addr);
 635 static DCDBAS_DEV_ATTR_WO(smi_request);
 636 static DCDBAS_DEV_ATTR_RW(host_control_action);
 637 static DCDBAS_DEV_ATTR_RW(host_control_smi_type);
 638 static DCDBAS_DEV_ATTR_RW(host_control_on_shutdown);
 639
 640 static struct attribute *dcdbas_dev_attrs[] = {
 641         &dev_attr_smi_data_buf_size.attr,
 642         &dev_attr_smi_data_buf_phys_addr.attr,
 643         &dev_attr_smi_request.attr,
 644         &dev_attr_host_control_action.attr,
 645         &dev_attr_host_control_smi_type.attr,
 646         &dev_attr_host_control_on_shutdown.attr,
 647         NULL
 648 };
 649
 650 static const struct attribute_group dcdbas_attr_group = {
 651         .attrs = dcdbas_dev_attrs,
 652         .bin_attrs = dcdbas_bin_attrs,
 653 };
 654
 655 static int dcdbas_probe(struct platform_device *dev)
 656 {
 657         int error;
 658
 659         host_control_action = HC_ACTION_NONE;
 660         host_control_smi_type = HC_SMITYPE_NONE;
 661
 662         dcdbas_pdev = dev;
 663
 664         /* Check if ACPI WSMT table specifies protected SMI buffer address */
 665         error = dcdbas_check_wsmt();
 666         if (error < 0)
 667                 return error;
 668
 669         /*
 670          * BIOS SMI calls require buffer addresses be in 32-bit address space.
 671          * This is done by setting the DMA mask below.
 672          */
 673         error = dma_set_coherent_mask(&dcdbas_pdev->dev, DMA_BIT_MASK(32));
 674         if (error)
 675                 return error;
 676
 677         error = sysfs_create_group(&dev->dev.kobj, &dcdbas_attr_group);
 678         if (error)
 679                 return error;
 680
 681         register_reboot_notifier(&dcdbas_reboot_nb);
 682
 683         dev_info(&dev->dev, "%s (version %s)\n",
 684                  DRIVER_DESCRIPTION, DRIVER_VERSION);
 685
 686         return 0;
 687 }
 688
 689 static int dcdbas_remove(struct platform_device *dev)
 690 {
 691         unregister_reboot_notifier(&dcdbas_reboot_nb);
 692         sysfs_remove_group(&dev->dev.kobj, &dcdbas_attr_group);
 693
 694         return 0;
 695 }
 696
 697 static struct platform_driver dcdbas_driver = {
 698         .driver         = {
 699                 .name   = DRIVER_NAME,
 700         },
 701         .probe          = dcdbas_probe,
 702         .remove         = dcdbas_remove,
 703 };
 704
 705 static const struct platform_device_info dcdbas_dev_info __initconst = {
 706         .name           = DRIVER_NAME,
 707         .id             = -1,
 708         .dma_mask       = DMA_BIT_MASK(32),
 709 };
 710
 711 static struct platform_device *dcdbas_pdev_reg;
 712
 713 /**
 714  * dcdbas_init: initialize driver
 715  */
 716 static int __init dcdbas_init(void)
 717 {
 718         int error;
 719
 720         error = platform_driver_register(&dcdbas_driver);
 721         if (error)
 722                 return error;
 723
 724         dcdbas_pdev_reg = platform_device_register_full(&dcdbas_dev_info);
 725         if (IS_ERR(dcdbas_pdev_reg)) {
 726                 error = PTR_ERR(dcdbas_pdev_reg);
 727                 goto err_unregister_driver;
 728         }
 729
 730         return 0;
 731
 732  err_unregister_driver:
 733         platform_driver_unregister(&dcdbas_driver);
 734         return error;
 735 }
 736
 737 /**
 738  * dcdbas_exit: perform driver cleanup
 739  */
 740 static void __exit dcdbas_exit(void)
 741 {
 742         /*
 743          * make sure functions that use dcdbas_pdev are called
 744          * before platform_device_unregister
 745          */
 746         unregister_reboot_notifier(&dcdbas_reboot_nb);
 747
 748         /*
 749          * We have to free the buffer here instead of dcdbas_remove
 750          * because only in module exit function we can be sure that
 751          * all sysfs attributes belonging to this module have been
 752          * released.
 753          */
 754         if (dcdbas_pdev)
 755                 smi_data_buf_free();
 756         if (bios_buffer)
 757                 memunmap(bios_buffer);
 758         platform_device_unregister(dcdbas_pdev_reg);
 759         platform_driver_unregister(&dcdbas_driver);
 760 }
 761
 762 subsys_initcall_sync(dcdbas_init);
 763 module_exit(dcdbas_exit);
 764
 765 MODULE_DESCRIPTION(DRIVER_DESCRIPTION " (version " DRIVER_VERSION ")");
 766 MODULE_VERSION(DRIVER_VERSION);
 767 MODULE_AUTHOR("Dell Inc.");
 768 MODULE_LICENSE("GPL");
 769 /* Any System or BIOS claiming to be by Dell */
 770 MODULE_ALIAS("dmi:*:[bs]vnD[Ee][Ll][Ll]*:*");