x86/dell/dcdbas.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  *  dcdbas.c: Dell Systems Management Base Driver
0004  *
0005  *  The Dell Systems Management Base Driver provides a sysfs interface for
0006  *  systems management software to perform System Management Interrupts (SMIs)
0007  *  and Host Control Actions (power cycle or power off after OS shutdown) on
0008  *  Dell systems.
0009  *
0010  *  See Documentation/driver-api/dcdbas.rst for more information.
0011  *
0012  *  Copyright (C) 1995-2006 Dell Inc.
0013  */
0014
0015 #include <linux/platform_device.h>
0016 #include <linux/acpi.h>
0017 #include <linux/dma-mapping.h>
0018 #include <linux/dmi.h>
0019 #include <linux/errno.h>
0020 #include <linux/cpu.h>
0021 #include <linux/gfp.h>
0022 #include <linux/init.h>
0023 #include <linux/io.h>
0024 #include <linux/kernel.h>
0025 #include <linux/mc146818rtc.h>
0026 #include <linux/module.h>
0027 #include <linux/reboot.h>
0028 #include <linux/sched.h>
0029 #include <linux/smp.h>
0030 #include <linux/spinlock.h>
0031 #include <linux/string.h>
0032 #include <linux/types.h>
0033 #include <linux/mutex.h>
0034
0035 #include "dcdbas.h"
0036
0037 #define DRIVER_NAME     "dcdbas"
0038 #define DRIVER_VERSION      "5.6.0-3.4"
0039 #define DRIVER_DESCRIPTION  "Dell Systems Management Base Driver"
0040
0041 static struct platform_device *dcdbas_pdev;
0042
0043 static unsigned long max_smi_data_buf_size = MAX_SMI_DATA_BUF_SIZE;
0044 static DEFINE_MUTEX(smi_data_lock);
0045 static u8 *bios_buffer;
0046 static struct smi_buffer smi_buf;
0047
0048 static unsigned int host_control_action;
0049 static unsigned int host_control_smi_type;
0050 static unsigned int host_control_on_shutdown;
0051
0052 static bool wsmt_enabled;
0053
0054 int dcdbas_smi_alloc(struct smi_buffer *smi_buffer, unsigned long size)
0055 {
0056     smi_buffer->virt = dma_alloc_coherent(&dcdbas_pdev->dev, size,
0057                           &smi_buffer->dma, GFP_KERNEL);
0058     if (!smi_buffer->virt) {
0059         dev_dbg(&dcdbas_pdev->dev,
0060             "%s: failed to allocate memory size %lu\n",
0061             __func__, size);
0062         return -ENOMEM;
0063     }
0064     smi_buffer->size = size;
0065
0066     dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
0067         __func__, (u32)smi_buffer->dma, smi_buffer->size);
0068
0069     return 0;
0070 }
0071 EXPORT_SYMBOL_GPL(dcdbas_smi_alloc);
0072
0073 void dcdbas_smi_free(struct smi_buffer *smi_buffer)
0074 {
0075     if (!smi_buffer->virt)
0076         return;
0077
0078     dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
0079         __func__, (u32)smi_buffer->dma, smi_buffer->size);
0080     dma_free_coherent(&dcdbas_pdev->dev, smi_buffer->size,
0081               smi_buffer->virt, smi_buffer->dma);
0082     smi_buffer->virt = NULL;
0083     smi_buffer->dma = 0;
0084     smi_buffer->size = 0;
0085 }
0086 EXPORT_SYMBOL_GPL(dcdbas_smi_free);
0087
0088 /**
0089  * smi_data_buf_free: free SMI data buffer
0090  */
0091 static void smi_data_buf_free(void)
0092 {
0093     if (!smi_buf.virt || wsmt_enabled)
0094         return;
0095
0096     dcdbas_smi_free(&smi_buf);
0097 }
0098
0099 /**
0100  * smi_data_buf_realloc: grow SMI data buffer if needed
0101  */
0102 static int smi_data_buf_realloc(unsigned long size)
0103 {
0104     struct smi_buffer tmp;
0105     int ret;
0106
0107     if (smi_buf.size >= size)
0108         return 0;
0109
0110     if (size > max_smi_data_buf_size)
0111         return -EINVAL;
0112
0113     /* new buffer is needed */
0114     ret = dcdbas_smi_alloc(&tmp, size);
0115     if (ret)
0116         return ret;
0117
0118     /* memory zeroed by dma_alloc_coherent */
0119     if (smi_buf.virt)
0120         memcpy(tmp.virt, smi_buf.virt, smi_buf.size);
0121
0122     /* free any existing buffer */
0123     smi_data_buf_free();
0124
0125     /* set up new buffer for use */
0126     smi_buf = tmp;
0127
0128     return 0;
0129 }
0130
0131 static ssize_t smi_data_buf_phys_addr_show(struct device *dev,
0132                        struct device_attribute *attr,
0133                        char *buf)
0134 {
0135     return sprintf(buf, "%x\n", (u32)smi_buf.dma);
0136 }
0137
0138 static ssize_t smi_data_buf_size_show(struct device *dev,
0139                       struct device_attribute *attr,
0140                       char *buf)
0141 {
0142     return sprintf(buf, "%lu\n", smi_buf.size);
0143 }
0144
0145 static ssize_t smi_data_buf_size_store(struct device *dev,
0146                        struct device_attribute *attr,
0147                        const char *buf, size_t count)
0148 {
0149     unsigned long buf_size;
0150     ssize_t ret;
0151
0152     buf_size = simple_strtoul(buf, NULL, 10);
0153
0154     /* make sure SMI data buffer is at least buf_size */
0155     mutex_lock(&smi_data_lock);
0156     ret = smi_data_buf_realloc(buf_size);
0157     mutex_unlock(&smi_data_lock);
0158     if (ret)
0159         return ret;
0160
0161     return count;
0162 }
0163
0164 static ssize_t smi_data_read(struct file *filp, struct kobject *kobj,
0165                  struct bin_attribute *bin_attr,
0166                  char *buf, loff_t pos, size_t count)
0167 {
0168     ssize_t ret;
0169
0170     mutex_lock(&smi_data_lock);
0171     ret = memory_read_from_buffer(buf, count, &pos, smi_buf.virt,
0172                     smi_buf.size);
0173     mutex_unlock(&smi_data_lock);
0174     return ret;
0175 }
0176
0177 static ssize_t smi_data_write(struct file *filp, struct kobject *kobj,
0178                   struct bin_attribute *bin_attr,
0179                   char *buf, loff_t pos, size_t count)
0180 {
0181     ssize_t ret;
0182
0183     if ((pos + count) > max_smi_data_buf_size)
0184         return -EINVAL;
0185
0186     mutex_lock(&smi_data_lock);
0187
0188     ret = smi_data_buf_realloc(pos + count);
0189     if (ret)
0190         goto out;
0191
0192     memcpy(smi_buf.virt + pos, buf, count);
0193     ret = count;
0194 out:
0195     mutex_unlock(&smi_data_lock);
0196     return ret;
0197 }
0198
0199 static ssize_t host_control_action_show(struct device *dev,
0200                     struct device_attribute *attr,
0201                     char *buf)
0202 {
0203     return sprintf(buf, "%u\n", host_control_action);
0204 }
0205
0206 static ssize_t host_control_action_store(struct device *dev,
0207                      struct device_attribute *attr,
0208                      const char *buf, size_t count)
0209 {
0210     ssize_t ret;
0211
0212     /* make sure buffer is available for host control command */
0213     mutex_lock(&smi_data_lock);
0214     ret = smi_data_buf_realloc(sizeof(struct apm_cmd));
0215     mutex_unlock(&smi_data_lock);
0216     if (ret)
0217         return ret;
0218
0219     host_control_action = simple_strtoul(buf, NULL, 10);
0220     return count;
0221 }
0222
0223 static ssize_t host_control_smi_type_show(struct device *dev,
0224                       struct device_attribute *attr,
0225                       char *buf)
0226 {
0227     return sprintf(buf, "%u\n", host_control_smi_type);
0228 }
0229
0230 static ssize_t host_control_smi_type_store(struct device *dev,
0231                        struct device_attribute *attr,
0232                        const char *buf, size_t count)
0233 {
0234     host_control_smi_type = simple_strtoul(buf, NULL, 10);
0235     return count;
0236 }
0237
0238 static ssize_t host_control_on_shutdown_show(struct device *dev,
0239                          struct device_attribute *attr,
0240                          char *buf)
0241 {
0242     return sprintf(buf, "%u\n", host_control_on_shutdown);
0243 }
0244
0245 static ssize_t host_control_on_shutdown_store(struct device *dev,
0246                           struct device_attribute *attr,
0247                           const char *buf, size_t count)
0248 {
0249     host_control_on_shutdown = simple_strtoul(buf, NULL, 10);
0250     return count;
0251 }
0252
0253 static int raise_smi(void *par)
0254 {
0255     struct smi_cmd *smi_cmd = par;
0256
0257     if (smp_processor_id() != 0) {
0258         dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0\n",
0259             __func__);
0260         return -EBUSY;
0261     }
0262
0263     /* generate SMI */
0264     /* inb to force posted write through and make SMI happen now */
0265     asm volatile (
0266         "outb %b0,%w1\n"
0267         "inb %w1"
0268         : /* no output args */
0269         : "a" (smi_cmd->command_code),
0270           "d" (smi_cmd->command_address),
0271           "b" (smi_cmd->ebx),
0272           "c" (smi_cmd->ecx)
0273         : "memory"
0274     );
0275
0276     return 0;
0277 }
0278 /**
0279  * dcdbas_smi_request: generate SMI request
0280  *
0281  * Called with smi_data_lock.
0282  */
0283 int dcdbas_smi_request(struct smi_cmd *smi_cmd)
0284 {
0285     int ret;
0286
0287     if (smi_cmd->magic != SMI_CMD_MAGIC) {
0288         dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",
0289              __func__);
0290         return -EBADR;
0291     }
0292
0293     /* SMI requires CPU 0 */
0294     cpus_read_lock();
0295     ret = smp_call_on_cpu(0, raise_smi, smi_cmd, true);
0296     cpus_read_unlock();
0297
0298     return ret;
0299 }
0300 EXPORT_SYMBOL(dcdbas_smi_request);
0301
0302 /**
0303  * smi_request_store:
0304  *
0305  * The valid values are:
0306  * 0: zero SMI data buffer
0307  * 1: generate calling interface SMI
0308  * 2: generate raw SMI
0309  *
0310  * User application writes smi_cmd to smi_data before telling driver
0311  * to generate SMI.
0312  */
0313 static ssize_t smi_request_store(struct device *dev,
0314                  struct device_attribute *attr,
0315                  const char *buf, size_t count)
0316 {
0317     struct smi_cmd *smi_cmd;
0318     unsigned long val = simple_strtoul(buf, NULL, 10);
0319     ssize_t ret;
0320
0321     mutex_lock(&smi_data_lock);
0322
0323     if (smi_buf.size < sizeof(struct smi_cmd)) {
0324         ret = -ENODEV;
0325         goto out;
0326     }
0327     smi_cmd = (struct smi_cmd *)smi_buf.virt;
0328
0329     switch (val) {
0330     case 2:
0331         /* Raw SMI */
0332         ret = dcdbas_smi_request(smi_cmd);
0333         if (!ret)
0334             ret = count;
0335         break;
0336     case 1:
0337         /*
0338          * Calling Interface SMI
0339          *
0340          * Provide physical address of command buffer field within
0341          * the struct smi_cmd to BIOS.
0342          *
0343          * Because the address that smi_cmd (smi_buf.virt) points to
0344          * will be from memremap() of a non-memory address if WSMT
0345          * is present, we can't use virt_to_phys() on smi_cmd, so
0346          * we have to use the physical address that was saved when
0347          * the virtual address for smi_cmd was received.
0348          */
0349         smi_cmd->ebx = (u32)smi_buf.dma +
0350                 offsetof(struct smi_cmd, command_buffer);
0351         ret = dcdbas_smi_request(smi_cmd);
0352         if (!ret)
0353             ret = count;
0354         break;
0355     case 0:
0356         memset(smi_buf.virt, 0, smi_buf.size);
0357         ret = count;
0358         break;
0359     default:
0360         ret = -EINVAL;
0361         break;
0362     }
0363
0364 out:
0365     mutex_unlock(&smi_data_lock);
0366     return ret;
0367 }
0368
0369 /**
0370  * host_control_smi: generate host control SMI
0371  *
0372  * Caller must set up the host control command in smi_buf.virt.
0373  */
0374 static int host_control_smi(void)
0375 {
0376     struct apm_cmd *apm_cmd;
0377     u8 *data;
0378     unsigned long flags;
0379     u32 num_ticks;
0380     s8 cmd_status;
0381     u8 index;
0382
0383     apm_cmd = (struct apm_cmd *)smi_buf.virt;
0384     apm_cmd->status = ESM_STATUS_CMD_UNSUCCESSFUL;
0385
0386     switch (host_control_smi_type) {
0387     case HC_SMITYPE_TYPE1:
0388         spin_lock_irqsave(&rtc_lock, flags);
0389         /* write SMI data buffer physical address */
0390         data = (u8 *)&smi_buf.dma;
0391         for (index = PE1300_CMOS_CMD_STRUCT_PTR;
0392              index < (PE1300_CMOS_CMD_STRUCT_PTR + 4);
0393              index++, data++) {
0394             outb(index,
0395                  (CMOS_BASE_PORT + CMOS_PAGE2_INDEX_PORT_PIIX4));
0396             outb(*data,
0397                  (CMOS_BASE_PORT + CMOS_PAGE2_DATA_PORT_PIIX4));
0398         }
0399
0400         /* first set status to -1 as called by spec */
0401         cmd_status = ESM_STATUS_CMD_UNSUCCESSFUL;
0402         outb((u8) cmd_status, PCAT_APM_STATUS_PORT);
0403
0404         /* generate SMM call */
0405         outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
0406         spin_unlock_irqrestore(&rtc_lock, flags);
0407
0408         /* wait a few to see if it executed */
0409         num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
0410         while ((s8)inb(PCAT_APM_STATUS_PORT) == ESM_STATUS_CMD_UNSUCCESSFUL) {
0411             num_ticks--;
0412             if (num_ticks == EXPIRED_TIMER)
0413                 return -ETIME;
0414         }
0415         break;
0416
0417     case HC_SMITYPE_TYPE2:
0418     case HC_SMITYPE_TYPE3:
0419         spin_lock_irqsave(&rtc_lock, flags);
0420         /* write SMI data buffer physical address */
0421         data = (u8 *)&smi_buf.dma;
0422         for (index = PE1400_CMOS_CMD_STRUCT_PTR;
0423              index < (PE1400_CMOS_CMD_STRUCT_PTR + 4);
0424              index++, data++) {
0425             outb(index, (CMOS_BASE_PORT + CMOS_PAGE1_INDEX_PORT));
0426             outb(*data, (CMOS_BASE_PORT + CMOS_PAGE1_DATA_PORT));
0427         }
0428
0429         /* generate SMM call */
0430         if (host_control_smi_type == HC_SMITYPE_TYPE3)
0431             outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
0432         else
0433             outb(ESM_APM_CMD, PE1400_APM_CONTROL_PORT);
0434
0435         /* restore RTC index pointer since it was written to above */
0436         CMOS_READ(RTC_REG_C);
0437         spin_unlock_irqrestore(&rtc_lock, flags);
0438
0439         /* read control port back to serialize write */
0440         cmd_status = inb(PE1400_APM_CONTROL_PORT);
0441
0442         /* wait a few to see if it executed */
0443         num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
0444         while (apm_cmd->status == ESM_STATUS_CMD_UNSUCCESSFUL) {
0445             num_ticks--;
0446             if (num_ticks == EXPIRED_TIMER)
0447                 return -ETIME;
0448         }
0449         break;
0450
0451     default:
0452         dev_dbg(&dcdbas_pdev->dev, "%s: invalid SMI type %u\n",
0453             __func__, host_control_smi_type);
0454         return -ENOSYS;
0455     }
0456
0457     return 0;
0458 }
0459
0460 /**
0461  * dcdbas_host_control: initiate host control
0462  *
0463  * This function is called by the driver after the system has
0464  * finished shutting down if the user application specified a
0465  * host control action to perform on shutdown.  It is safe to
0466  * use smi_buf.virt at this point because the system has finished
0467  * shutting down and no userspace apps are running.
0468  */
0469 static void dcdbas_host_control(void)
0470 {
0471     struct apm_cmd *apm_cmd;
0472     u8 action;
0473
0474     if (host_control_action == HC_ACTION_NONE)
0475         return;
0476
0477     action = host_control_action;
0478     host_control_action = HC_ACTION_NONE;
0479
0480     if (!smi_buf.virt) {
0481         dev_dbg(&dcdbas_pdev->dev, "%s: no SMI buffer\n", __func__);
0482         return;
0483     }
0484
0485     if (smi_buf.size < sizeof(struct apm_cmd)) {
0486         dev_dbg(&dcdbas_pdev->dev, "%s: SMI buffer too small\n",
0487             __func__);
0488         return;
0489     }
0490
0491     apm_cmd = (struct apm_cmd *)smi_buf.virt;
0492
0493     /* power off takes precedence */
0494     if (action & HC_ACTION_HOST_CONTROL_POWEROFF) {
0495         apm_cmd->command = ESM_APM_POWER_CYCLE;
0496         apm_cmd->reserved = 0;
0497         *((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 0;
0498         host_control_smi();
0499     } else if (action & HC_ACTION_HOST_CONTROL_POWERCYCLE) {
0500         apm_cmd->command = ESM_APM_POWER_CYCLE;
0501         apm_cmd->reserved = 0;
0502         *((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 20;
0503         host_control_smi();
0504     }
0505 }
0506
0507 /* WSMT */
0508
0509 static u8 checksum(u8 *buffer, u8 length)
0510 {
0511     u8 sum = 0;
0512     u8 *end = buffer + length;
0513
0514     while (buffer < end)
0515         sum += *buffer++;
0516     return sum;
0517 }
0518
0519 static inline struct smm_eps_table *check_eps_table(u8 *addr)
0520 {
0521     struct smm_eps_table *eps = (struct smm_eps_table *)addr;
0522
0523     if (strncmp(eps->smm_comm_buff_anchor, SMM_EPS_SIG, 4) != 0)
0524         return NULL;
0525
0526     if (checksum(addr, eps->length) != 0)
0527         return NULL;
0528
0529     return eps;
0530 }
0531
0532 static int dcdbas_check_wsmt(void)
0533 {
0534     const struct dmi_device *dev = NULL;
0535     struct acpi_table_wsmt *wsmt = NULL;
0536     struct smm_eps_table *eps = NULL;
0537     u64 bios_buf_paddr;
0538     u64 remap_size;
0539     u8 *addr;
0540
0541     acpi_get_table(ACPI_SIG_WSMT, 0, (struct acpi_table_header **)&wsmt);
0542     if (!wsmt)
0543         return 0;
0544
0545     /* Check if WSMT ACPI table shows that protection is enabled */
0546     if (!(wsmt->protection_flags & ACPI_WSMT_FIXED_COMM_BUFFERS) ||
0547         !(wsmt->protection_flags & ACPI_WSMT_COMM_BUFFER_NESTED_PTR_PROTECTION))
0548         return 0;
0549
0550     /*
0551      * BIOS could provide the address/size of the protected buffer
0552      * in an SMBIOS string or in an EPS structure in 0xFxxxx.
0553      */
0554
0555     /* Check SMBIOS for buffer address */
0556     while ((dev = dmi_find_device(DMI_DEV_TYPE_OEM_STRING, NULL, dev)))
0557         if (sscanf(dev->name, "30[%16llx;%8llx]", &bios_buf_paddr,
0558             &remap_size) == 2)
0559             goto remap;
0560
0561     /* Scan for EPS (entry point structure) */
0562     for (addr = (u8 *)__va(0xf0000);
0563          addr < (u8 *)__va(0x100000 - sizeof(struct smm_eps_table));
0564          addr += 16) {
0565         eps = check_eps_table(addr);
0566         if (eps)
0567             break;
0568     }
0569
0570     if (!eps) {
0571         dev_dbg(&dcdbas_pdev->dev, "found WSMT, but no firmware buffer found\n");
0572         return -ENODEV;
0573     }
0574     bios_buf_paddr = eps->smm_comm_buff_addr;
0575     remap_size = eps->num_of_4k_pages * PAGE_SIZE;
0576
0577 remap:
0578     /*
0579      * Get physical address of buffer and map to virtual address.
0580      * Table gives size in 4K pages, regardless of actual system page size.
0581      */
0582     if (upper_32_bits(bios_buf_paddr + 8)) {
0583         dev_warn(&dcdbas_pdev->dev, "found WSMT, but buffer address is above 4GB\n");
0584         return -EINVAL;
0585     }
0586     /*
0587      * Limit remap size to MAX_SMI_DATA_BUF_SIZE + 8 (since the first 8
0588      * bytes are used for a semaphore, not the data buffer itself).
0589      */
0590     if (remap_size > MAX_SMI_DATA_BUF_SIZE + 8)
0591         remap_size = MAX_SMI_DATA_BUF_SIZE + 8;
0592
0593     bios_buffer = memremap(bios_buf_paddr, remap_size, MEMREMAP_WB);
0594     if (!bios_buffer) {
0595         dev_warn(&dcdbas_pdev->dev, "found WSMT, but failed to map buffer\n");
0596         return -ENOMEM;
0597     }
0598
0599     /* First 8 bytes is for a semaphore, not part of the smi_buf.virt */
0600     smi_buf.dma = bios_buf_paddr + 8;
0601     smi_buf.virt = bios_buffer + 8;
0602     smi_buf.size = remap_size - 8;
0603     max_smi_data_buf_size = smi_buf.size;
0604     wsmt_enabled = true;
0605     dev_info(&dcdbas_pdev->dev,
0606          "WSMT found, using firmware-provided SMI buffer.\n");
0607     return 1;
0608 }
0609
0610 /**
0611  * dcdbas_reboot_notify: handle reboot notification for host control
0612  */
0613 static int dcdbas_reboot_notify(struct notifier_block *nb, unsigned long code,
0614                 void *unused)
0615 {
0616     switch (code) {
0617     case SYS_DOWN:
0618     case SYS_HALT:
0619     case SYS_POWER_OFF:
0620         if (host_control_on_shutdown) {
0621             /* firmware is going to perform host control action */
0622             printk(KERN_WARNING "Please wait for shutdown "
0623                    "action to complete...\n");
0624             dcdbas_host_control();
0625         }
0626         break;
0627     }
0628
0629     return NOTIFY_DONE;
0630 }
0631
0632 static struct notifier_block dcdbas_reboot_nb = {
0633     .notifier_call = dcdbas_reboot_notify,
0634     .next = NULL,
0635     .priority = INT_MIN
0636 };
0637
0638 static DCDBAS_BIN_ATTR_RW(smi_data);
0639
0640 static struct bin_attribute *dcdbas_bin_attrs[] = {
0641     &bin_attr_smi_data,
0642     NULL
0643 };
0644
0645 static DCDBAS_DEV_ATTR_RW(smi_data_buf_size);
0646 static DCDBAS_DEV_ATTR_RO(smi_data_buf_phys_addr);
0647 static DCDBAS_DEV_ATTR_WO(smi_request);
0648 static DCDBAS_DEV_ATTR_RW(host_control_action);
0649 static DCDBAS_DEV_ATTR_RW(host_control_smi_type);
0650 static DCDBAS_DEV_ATTR_RW(host_control_on_shutdown);
0651
0652 static struct attribute *dcdbas_dev_attrs[] = {
0653     &dev_attr_smi_data_buf_size.attr,
0654     &dev_attr_smi_data_buf_phys_addr.attr,
0655     &dev_attr_smi_request.attr,
0656     &dev_attr_host_control_action.attr,
0657     &dev_attr_host_control_smi_type.attr,
0658     &dev_attr_host_control_on_shutdown.attr,
0659     NULL
0660 };
0661
0662 static const struct attribute_group dcdbas_attr_group = {
0663     .attrs = dcdbas_dev_attrs,
0664     .bin_attrs = dcdbas_bin_attrs,
0665 };
0666
0667 static int dcdbas_probe(struct platform_device *dev)
0668 {
0669     int error;
0670
0671     host_control_action = HC_ACTION_NONE;
0672     host_control_smi_type = HC_SMITYPE_NONE;
0673
0674     dcdbas_pdev = dev;
0675
0676     /* Check if ACPI WSMT table specifies protected SMI buffer address */
0677     error = dcdbas_check_wsmt();
0678     if (error < 0)
0679         return error;
0680
0681     /*
0682      * BIOS SMI calls require buffer addresses be in 32-bit address space.
0683      * This is done by setting the DMA mask below.
0684      */
0685     error = dma_set_coherent_mask(&dcdbas_pdev->dev, DMA_BIT_MASK(32));
0686     if (error)
0687         return error;
0688
0689     error = sysfs_create_group(&dev->dev.kobj, &dcdbas_attr_group);
0690     if (error)
0691         return error;
0692
0693     register_reboot_notifier(&dcdbas_reboot_nb);
0694
0695     dev_info(&dev->dev, "%s (version %s)\n",
0696          DRIVER_DESCRIPTION, DRIVER_VERSION);
0697
0698     return 0;
0699 }
0700
0701 static int dcdbas_remove(struct platform_device *dev)
0702 {
0703     unregister_reboot_notifier(&dcdbas_reboot_nb);
0704     sysfs_remove_group(&dev->dev.kobj, &dcdbas_attr_group);
0705
0706     return 0;
0707 }
0708
0709 static struct platform_driver dcdbas_driver = {
0710     .driver     = {
0711         .name   = DRIVER_NAME,
0712     },
0713     .probe      = dcdbas_probe,
0714     .remove     = dcdbas_remove,
0715 };
0716
0717 static const struct platform_device_info dcdbas_dev_info __initconst = {
0718     .name       = DRIVER_NAME,
0719     .id     = -1,
0720     .dma_mask   = DMA_BIT_MASK(32),
0721 };
0722
0723 static struct platform_device *dcdbas_pdev_reg;
0724
0725 /**
0726  * dcdbas_init: initialize driver
0727  */
0728 static int __init dcdbas_init(void)
0729 {
0730     int error;
0731
0732     error = platform_driver_register(&dcdbas_driver);
0733     if (error)
0734         return error;
0735
0736     dcdbas_pdev_reg = platform_device_register_full(&dcdbas_dev_info);
0737     if (IS_ERR(dcdbas_pdev_reg)) {
0738         error = PTR_ERR(dcdbas_pdev_reg);
0739         goto err_unregister_driver;
0740     }
0741
0742     return 0;
0743
0744  err_unregister_driver:
0745     platform_driver_unregister(&dcdbas_driver);
0746     return error;
0747 }
0748
0749 /**
0750  * dcdbas_exit: perform driver cleanup
0751  */
0752 static void __exit dcdbas_exit(void)
0753 {
0754     /*
0755      * make sure functions that use dcdbas_pdev are called
0756      * before platform_device_unregister
0757      */
0758     unregister_reboot_notifier(&dcdbas_reboot_nb);
0759
0760     /*
0761      * We have to free the buffer here instead of dcdbas_remove
0762      * because only in module exit function we can be sure that
0763      * all sysfs attributes belonging to this module have been
0764      * released.
0765      */
0766     if (dcdbas_pdev)
0767         smi_data_buf_free();
0768     if (bios_buffer)
0769         memunmap(bios_buffer);
0770     platform_device_unregister(dcdbas_pdev_reg);
0771     platform_driver_unregister(&dcdbas_driver);
0772 }
0773
0774 subsys_initcall_sync(dcdbas_init);
0775 module_exit(dcdbas_exit);
0776
0777 MODULE_DESCRIPTION(DRIVER_DESCRIPTION " (version " DRIVER_VERSION ")");
0778 MODULE_VERSION(DRIVER_VERSION);
0779 MODULE_AUTHOR("Dell Inc.");
0780 MODULE_LICENSE("GPL");
0781 /* Any System or BIOS claiming to be by Dell */
0782 MODULE_ALIAS("dmi:*:[bs]vnD[Ee][Ll][Ll]*:*");