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/errno.h>
  19 #include <linux/cpu.h>
  20 #include <linux/gfp.h>
  21 #include <linux/init.h>
  22 #include <linux/io.h>
  23 #include <linux/kernel.h>
  24 #include <linux/mc146818rtc.h>
  25 #include <linux/module.h>
  26 #include <linux/reboot.h>
  27 #include <linux/sched.h>
  28 #include <linux/smp.h>
  29 #include <linux/spinlock.h>
  30 #include <linux/string.h>
  31 #include <linux/types.h>
  32 #include <linux/mutex.h>
  33
  34 #include "dcdbas.h"
  35
  36 #define DRIVER_NAME             "dcdbas"
  37 #define DRIVER_VERSION          "5.6.0-3.3"
  38 #define DRIVER_DESCRIPTION      "Dell Systems Management Base Driver"
  39
  40 static struct platform_device *dcdbas_pdev;
  41
  42 static u8 *smi_data_buf;
  43 static dma_addr_t smi_data_buf_handle;
  44 static unsigned long smi_data_buf_size;
  45 static unsigned long max_smi_data_buf_size = MAX_SMI_DATA_BUF_SIZE;
  46 static u32 smi_data_buf_phys_addr;
  47 static DEFINE_MUTEX(smi_data_lock);
  48 static u8 *eps_buffer;
  49
  50 static unsigned int host_control_action;
  51 static unsigned int host_control_smi_type;
  52 static unsigned int host_control_on_shutdown;
  53
  54 static bool wsmt_enabled;
  55
  56 /**
  57  * smi_data_buf_free: free SMI data buffer
  58  */
  59 static void smi_data_buf_free(void)
  60 {
  61         if (!smi_data_buf || wsmt_enabled)
  62                 return;
  63
  64         dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
  65                 __func__, smi_data_buf_phys_addr, smi_data_buf_size);
  66
  67         dma_free_coherent(&dcdbas_pdev->dev, smi_data_buf_size, smi_data_buf,
  68                           smi_data_buf_handle);
  69         smi_data_buf = NULL;
  70         smi_data_buf_handle = 0;
  71         smi_data_buf_phys_addr = 0;
  72         smi_data_buf_size = 0;
  73 }
  74
  75 /**
  76  * smi_data_buf_realloc: grow SMI data buffer if needed
  77  */
  78 static int smi_data_buf_realloc(unsigned long size)
  79 {
  80         void *buf;
  81         dma_addr_t handle;
  82
  83         if (smi_data_buf_size >= size)
  84                 return 0;
  85
  86         if (size > max_smi_data_buf_size)
  87                 return -EINVAL;
  88
  89         /* new buffer is needed */
  90         buf = dma_alloc_coherent(&dcdbas_pdev->dev, size, &handle, GFP_KERNEL);
  91         if (!buf) {
  92                 dev_dbg(&dcdbas_pdev->dev,
  93                         "%s: failed to allocate memory size %lu\n",
  94                         __func__, size);
  95                 return -ENOMEM;
  96         }
  97         /* memory zeroed by dma_alloc_coherent */
  98
  99         if (smi_data_buf)
 100                 memcpy(buf, smi_data_buf, smi_data_buf_size);
 101
 102         /* free any existing buffer */
 103         smi_data_buf_free();
 104
 105         /* set up new buffer for use */
 106         smi_data_buf = buf;
 107         smi_data_buf_handle = handle;
 108         smi_data_buf_phys_addr = (u32) virt_to_phys(buf);
 109         smi_data_buf_size = size;
 110
 111         dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
 112                 __func__, smi_data_buf_phys_addr, smi_data_buf_size);
 113
 114         return 0;
 115 }
 116
 117 static ssize_t smi_data_buf_phys_addr_show(struct device *dev,
 118                                            struct device_attribute *attr,
 119                                            char *buf)
 120 {
 121         return sprintf(buf, "%x\n", smi_data_buf_phys_addr);
 122 }
 123
 124 static ssize_t smi_data_buf_size_show(struct device *dev,
 125                                       struct device_attribute *attr,
 126                                       char *buf)
 127 {
 128         return sprintf(buf, "%lu\n", smi_data_buf_size);
 129 }
 130
 131 static ssize_t smi_data_buf_size_store(struct device *dev,
 132                                        struct device_attribute *attr,
 133                                        const char *buf, size_t count)
 134 {
 135         unsigned long buf_size;
 136         ssize_t ret;
 137
 138         buf_size = simple_strtoul(buf, NULL, 10);
 139
 140         /* make sure SMI data buffer is at least buf_size */
 141         mutex_lock(&smi_data_lock);
 142         ret = smi_data_buf_realloc(buf_size);
 143         mutex_unlock(&smi_data_lock);
 144         if (ret)
 145                 return ret;
 146
 147         return count;
 148 }
 149
 150 static ssize_t smi_data_read(struct file *filp, struct kobject *kobj,
 151                              struct bin_attribute *bin_attr,
 152                              char *buf, loff_t pos, size_t count)
 153 {
 154         ssize_t ret;
 155
 156         mutex_lock(&smi_data_lock);
 157         ret = memory_read_from_buffer(buf, count, &pos, smi_data_buf,
 158                                         smi_data_buf_size);
 159         mutex_unlock(&smi_data_lock);
 160         return ret;
 161 }
 162
 163 static ssize_t smi_data_write(struct file *filp, struct kobject *kobj,
 164                               struct bin_attribute *bin_attr,
 165                               char *buf, loff_t pos, size_t count)
 166 {
 167         ssize_t ret;
 168
 169         if ((pos + count) > max_smi_data_buf_size)
 170                 return -EINVAL;
 171
 172         mutex_lock(&smi_data_lock);
 173
 174         ret = smi_data_buf_realloc(pos + count);
 175         if (ret)
 176                 goto out;
 177
 178         memcpy(smi_data_buf + pos, buf, count);
 179         ret = count;
 180 out:
 181         mutex_unlock(&smi_data_lock);
 182         return ret;
 183 }
 184
 185 static ssize_t host_control_action_show(struct device *dev,
 186                                         struct device_attribute *attr,
 187                                         char *buf)
 188 {
 189         return sprintf(buf, "%u\n", host_control_action);
 190 }
 191
 192 static ssize_t host_control_action_store(struct device *dev,
 193                                          struct device_attribute *attr,
 194                                          const char *buf, size_t count)
 195 {
 196         ssize_t ret;
 197
 198         /* make sure buffer is available for host control command */
 199         mutex_lock(&smi_data_lock);
 200         ret = smi_data_buf_realloc(sizeof(struct apm_cmd));
 201         mutex_unlock(&smi_data_lock);
 202         if (ret)
 203                 return ret;
 204
 205         host_control_action = simple_strtoul(buf, NULL, 10);
 206         return count;
 207 }
 208
 209 static ssize_t host_control_smi_type_show(struct device *dev,
 210                                           struct device_attribute *attr,
 211                                           char *buf)
 212 {
 213         return sprintf(buf, "%u\n", host_control_smi_type);
 214 }
 215
 216 static ssize_t host_control_smi_type_store(struct device *dev,
 217                                            struct device_attribute *attr,
 218                                            const char *buf, size_t count)
 219 {
 220         host_control_smi_type = simple_strtoul(buf, NULL, 10);
 221         return count;
 222 }
 223
 224 static ssize_t host_control_on_shutdown_show(struct device *dev,
 225                                              struct device_attribute *attr,
 226                                              char *buf)
 227 {
 228         return sprintf(buf, "%u\n", host_control_on_shutdown);
 229 }
 230
 231 static ssize_t host_control_on_shutdown_store(struct device *dev,
 232                                               struct device_attribute *attr,
 233                                               const char *buf, size_t count)
 234 {
 235         host_control_on_shutdown = simple_strtoul(buf, NULL, 10);
 236         return count;
 237 }
 238
 239 static int raise_smi(void *par)
 240 {
 241         struct smi_cmd *smi_cmd = par;
 242
 243         if (smp_processor_id() != 0) {
 244                 dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0\n",
 245                         __func__);
 246                 return -EBUSY;
 247         }
 248
 249         /* generate SMI */
 250         /* inb to force posted write through and make SMI happen now */
 251         asm volatile (
 252                 "outb %b0,%w1\n"
 253                 "inb %w1"
 254                 : /* no output args */
 255                 : "a" (smi_cmd->command_code),
 256                   "d" (smi_cmd->command_address),
 257                   "b" (smi_cmd->ebx),
 258                   "c" (smi_cmd->ecx)
 259                 : "memory"
 260         );
 261
 262         return 0;
 263 }
 264 /**
 265  * dcdbas_smi_request: generate SMI request
 266  *
 267  * Called with smi_data_lock.
 268  */
 269 int dcdbas_smi_request(struct smi_cmd *smi_cmd)
 270 {
 271         int ret;
 272
 273         if (smi_cmd->magic != SMI_CMD_MAGIC) {
 274                 dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",
 275                          __func__);
 276                 return -EBADR;
 277         }
 278
 279         /* SMI requires CPU 0 */
 280         get_online_cpus();
 281         ret = smp_call_on_cpu(0, raise_smi, smi_cmd, true);
 282         put_online_cpus();
 283
 284         return ret;
 285 }
 286
 287 /**
 288  * smi_request_store:
 289  *
 290  * The valid values are:
 291  * 0: zero SMI data buffer
 292  * 1: generate calling interface SMI
 293  * 2: generate raw SMI
 294  *
 295  * User application writes smi_cmd to smi_data before telling driver
 296  * to generate SMI.
 297  */
 298 static ssize_t smi_request_store(struct device *dev,
 299                                  struct device_attribute *attr,
 300                                  const char *buf, size_t count)
 301 {
 302         struct smi_cmd *smi_cmd;
 303         unsigned long val = simple_strtoul(buf, NULL, 10);
 304         ssize_t ret;
 305
 306         mutex_lock(&smi_data_lock);
 307
 308         if (smi_data_buf_size < sizeof(struct smi_cmd)) {
 309                 ret = -ENODEV;
 310                 goto out;
 311         }
 312         smi_cmd = (struct smi_cmd *)smi_data_buf;
 313
 314         switch (val) {
 315         case 2:
 316                 /* Raw SMI */
 317                 ret = dcdbas_smi_request(smi_cmd);
 318                 if (!ret)
 319                         ret = count;
 320                 break;
 321         case 1:
 322                 /*
 323                  * Calling Interface SMI
 324                  *
 325                  * Provide physical address of command buffer field within
 326                  * the struct smi_cmd to BIOS.
 327                  *
 328                  * Because the address that smi_cmd (smi_data_buf) points to
 329                  * will be from memremap() of a non-memory address if WSMT
 330                  * is present, we can't use virt_to_phys() on smi_cmd, so
 331                  * we have to use the physical address that was saved when
 332                  * the virtual address for smi_cmd was received.
 333                  */
 334                 smi_cmd->ebx = smi_data_buf_phys_addr +
 335                                 offsetof(struct smi_cmd, command_buffer);
 336                 ret = dcdbas_smi_request(smi_cmd);
 337                 if (!ret)
 338                         ret = count;
 339                 break;
 340         case 0:
 341                 memset(smi_data_buf, 0, smi_data_buf_size);
 342                 ret = count;
 343                 break;
 344         default:
 345                 ret = -EINVAL;
 346                 break;
 347         }
 348
 349 out:
 350         mutex_unlock(&smi_data_lock);
 351         return ret;
 352 }
 353 EXPORT_SYMBOL(dcdbas_smi_request);
 354
 355 /**
 356  * host_control_smi: generate host control SMI
 357  *
 358  * Caller must set up the host control command in smi_data_buf.
 359  */
 360 static int host_control_smi(void)
 361 {
 362         struct apm_cmd *apm_cmd;
 363         u8 *data;
 364         unsigned long flags;
 365         u32 num_ticks;
 366         s8 cmd_status;
 367         u8 index;
 368
 369         apm_cmd = (struct apm_cmd *)smi_data_buf;
 370         apm_cmd->status = ESM_STATUS_CMD_UNSUCCESSFUL;
 371
 372         switch (host_control_smi_type) {
 373         case HC_SMITYPE_TYPE1:
 374                 spin_lock_irqsave(&rtc_lock, flags);
 375                 /* write SMI data buffer physical address */
 376                 data = (u8 *)&smi_data_buf_phys_addr;
 377                 for (index = PE1300_CMOS_CMD_STRUCT_PTR;
 378                      index < (PE1300_CMOS_CMD_STRUCT_PTR + 4);
 379                      index++, data++) {
 380                         outb(index,
 381                              (CMOS_BASE_PORT + CMOS_PAGE2_INDEX_PORT_PIIX4));
 382                         outb(*data,
 383                              (CMOS_BASE_PORT + CMOS_PAGE2_DATA_PORT_PIIX4));
 384                 }
 385
 386                 /* first set status to -1 as called by spec */
 387                 cmd_status = ESM_STATUS_CMD_UNSUCCESSFUL;
 388                 outb((u8) cmd_status, PCAT_APM_STATUS_PORT);
 389
 390                 /* generate SMM call */
 391                 outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
 392                 spin_unlock_irqrestore(&rtc_lock, flags);
 393
 394                 /* wait a few to see if it executed */
 395                 num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
 396                 while ((cmd_status = inb(PCAT_APM_STATUS_PORT))
 397                        == 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  */
 456 static 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
 496 static 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
 506 static 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
 519 static int dcdbas_check_wsmt(void)
 520 {
 521         struct acpi_table_wsmt *wsmt = NULL;
 522         struct smm_eps_table *eps = NULL;
 523         u64 remap_size;
 524         u8 *addr;
 525
 526         acpi_get_table(ACPI_SIG_WSMT, 0, (struct acpi_table_header **)&wsmt);
 527         if (!wsmt)
 528                 return 0;
 529
 530         /* Check if WSMT ACPI table shows that protection is enabled */
 531         if (!(wsmt->protection_flags & ACPI_WSMT_FIXED_COMM_BUFFERS) ||
 532             !(wsmt->protection_flags & ACPI_WSMT_COMM_BUFFER_NESTED_PTR_PROTECTION))
 533                 return 0;
 534
 535         /* Scan for EPS (entry point structure) */
 536         for (addr = (u8 *)__va(0xf0000);
 537              addr < (u8 *)__va(0x100000 - sizeof(struct smm_eps_table));
 538              addr += 16) {
 539                 eps = check_eps_table(addr);
 540                 if (eps)
 541                         break;
 542         }
 543
 544         if (!eps) {
 545                 dev_dbg(&dcdbas_pdev->dev, "found WSMT, but no EPS found\n");
 546                 return -ENODEV;
 547         }
 548
 549         /*
 550          * Get physical address of buffer and map to virtual address.
 551          * Table gives size in 4K pages, regardless of actual system page size.
 552          */
 553         if (upper_32_bits(eps->smm_comm_buff_addr + 8)) {
 554                 dev_warn(&dcdbas_pdev->dev, "found WSMT, but EPS buffer address is above 4GB\n");
 555                 return -EINVAL;
 556         }
 557         /*
 558          * Limit remap size to MAX_SMI_DATA_BUF_SIZE + 8 (since the first 8
 559          * bytes are used for a semaphore, not the data buffer itself).
 560          */
 561         remap_size = eps->num_of_4k_pages * PAGE_SIZE;
 562         if (remap_size > MAX_SMI_DATA_BUF_SIZE + 8)
 563                 remap_size = MAX_SMI_DATA_BUF_SIZE + 8;
 564         eps_buffer = memremap(eps->smm_comm_buff_addr, remap_size, MEMREMAP_WB);
 565         if (!eps_buffer) {
 566                 dev_warn(&dcdbas_pdev->dev, "found WSMT, but failed to map EPS buffer\n");
 567                 return -ENOMEM;
 568         }
 569
 570         /* First 8 bytes is for a semaphore, not part of the smi_data_buf */
 571         smi_data_buf_phys_addr = eps->smm_comm_buff_addr + 8;
 572         smi_data_buf = eps_buffer + 8;
 573         smi_data_buf_size = remap_size - 8;
 574         max_smi_data_buf_size = smi_data_buf_size;
 575         wsmt_enabled = true;
 576         dev_info(&dcdbas_pdev->dev,
 577                  "WSMT found, using firmware-provided SMI buffer.\n");
 578         return 1;
 579 }
 580
 581 /**
 582  * dcdbas_reboot_notify: handle reboot notification for host control
 583  */
 584 static int dcdbas_reboot_notify(struct notifier_block *nb, unsigned long code,
 585                                 void *unused)
 586 {
 587         switch (code) {
 588         case SYS_DOWN:
 589         case SYS_HALT:
 590         case SYS_POWER_OFF:
 591                 if (host_control_on_shutdown) {
 592                         /* firmware is going to perform host control action */
 593                         printk(KERN_WARNING "Please wait for shutdown "
 594                                "action to complete...\n");
 595                         dcdbas_host_control();
 596                 }
 597                 break;
 598         }
 599
 600         return NOTIFY_DONE;
 601 }
 602
 603 static struct notifier_block dcdbas_reboot_nb = {
 604         .notifier_call = dcdbas_reboot_notify,
 605         .next = NULL,
 606         .priority = INT_MIN
 607 };
 608
 609 static DCDBAS_BIN_ATTR_RW(smi_data);
 610
 611 static struct bin_attribute *dcdbas_bin_attrs[] = {
 612         &bin_attr_smi_data,
 613         NULL
 614 };
 615
 616 static DCDBAS_DEV_ATTR_RW(smi_data_buf_size);
 617 static DCDBAS_DEV_ATTR_RO(smi_data_buf_phys_addr);
 618 static DCDBAS_DEV_ATTR_WO(smi_request);
 619 static DCDBAS_DEV_ATTR_RW(host_control_action);
 620 static DCDBAS_DEV_ATTR_RW(host_control_smi_type);
 621 static DCDBAS_DEV_ATTR_RW(host_control_on_shutdown);
 622
 623 static struct attribute *dcdbas_dev_attrs[] = {
 624         &dev_attr_smi_data_buf_size.attr,
 625         &dev_attr_smi_data_buf_phys_addr.attr,
 626         &dev_attr_smi_request.attr,
 627         &dev_attr_host_control_action.attr,
 628         &dev_attr_host_control_smi_type.attr,
 629         &dev_attr_host_control_on_shutdown.attr,
 630         NULL
 631 };
 632
 633 static const struct attribute_group dcdbas_attr_group = {
 634         .attrs = dcdbas_dev_attrs,
 635         .bin_attrs = dcdbas_bin_attrs,
 636 };
 637
 638 static int dcdbas_probe(struct platform_device *dev)
 639 {
 640         int error;
 641
 642         host_control_action = HC_ACTION_NONE;
 643         host_control_smi_type = HC_SMITYPE_NONE;
 644
 645         dcdbas_pdev = dev;
 646
 647         /* Check if ACPI WSMT table specifies protected SMI buffer address */
 648         error = dcdbas_check_wsmt();
 649         if (error < 0)
 650                 return error;
 651
 652         /*
 653          * BIOS SMI calls require buffer addresses be in 32-bit address space.
 654          * This is done by setting the DMA mask below.
 655          */
 656         error = dma_set_coherent_mask(&dcdbas_pdev->dev, DMA_BIT_MASK(32));
 657         if (error)
 658                 return error;
 659
 660         error = sysfs_create_group(&dev->dev.kobj, &dcdbas_attr_group);
 661         if (error)
 662                 return error;
 663
 664         register_reboot_notifier(&dcdbas_reboot_nb);
 665
 666         dev_info(&dev->dev, "%s (version %s)\n",
 667                  DRIVER_DESCRIPTION, DRIVER_VERSION);
 668
 669         return 0;
 670 }
 671
 672 static int dcdbas_remove(struct platform_device *dev)
 673 {
 674         unregister_reboot_notifier(&dcdbas_reboot_nb);
 675         sysfs_remove_group(&dev->dev.kobj, &dcdbas_attr_group);
 676
 677         return 0;
 678 }
 679
 680 static struct platform_driver dcdbas_driver = {
 681         .driver         = {
 682                 .name   = DRIVER_NAME,
 683         },
 684         .probe          = dcdbas_probe,
 685         .remove         = dcdbas_remove,
 686 };
 687
 688 static const struct platform_device_info dcdbas_dev_info __initconst = {
 689         .name           = DRIVER_NAME,
 690         .id             = -1,
 691         .dma_mask       = DMA_BIT_MASK(32),
 692 };
 693
 694 static struct platform_device *dcdbas_pdev_reg;
 695
 696 /**
 697  * dcdbas_init: initialize driver
 698  */
 699 static int __init dcdbas_init(void)
 700 {
 701         int error;
 702
 703         error = platform_driver_register(&dcdbas_driver);
 704         if (error)
 705                 return error;
 706
 707         dcdbas_pdev_reg = platform_device_register_full(&dcdbas_dev_info);
 708         if (IS_ERR(dcdbas_pdev_reg)) {
 709                 error = PTR_ERR(dcdbas_pdev_reg);
 710                 goto err_unregister_driver;
 711         }
 712
 713         return 0;
 714
 715  err_unregister_driver:
 716         platform_driver_unregister(&dcdbas_driver);
 717         return error;
 718 }
 719
 720 /**
 721  * dcdbas_exit: perform driver cleanup
 722  */
 723 static void __exit dcdbas_exit(void)
 724 {
 725         /*
 726          * make sure functions that use dcdbas_pdev are called
 727          * before platform_device_unregister
 728          */
 729         unregister_reboot_notifier(&dcdbas_reboot_nb);
 730
 731         /*
 732          * We have to free the buffer here instead of dcdbas_remove
 733          * because only in module exit function we can be sure that
 734          * all sysfs attributes belonging to this module have been
 735          * released.
 736          */
 737         if (dcdbas_pdev)
 738                 smi_data_buf_free();
 739         if (eps_buffer)
 740                 memunmap(eps_buffer);
 741         platform_device_unregister(dcdbas_pdev_reg);
 742         platform_driver_unregister(&dcdbas_driver);
 743 }
 744
 745 subsys_initcall_sync(dcdbas_init);
 746 module_exit(dcdbas_exit);
 747
 748 MODULE_DESCRIPTION(DRIVER_DESCRIPTION " (version " DRIVER_VERSION ")");
 749 MODULE_VERSION(DRIVER_VERSION);
 750 MODULE_AUTHOR("Dell Inc.");
 751 MODULE_LICENSE("GPL");
 752 /* Any System or BIOS claiming to be by Dell */
 753 MODULE_ALIAS("dmi:*:[bs]vnD[Ee][Ll][Ll]*:*");