summaryrefslogtreecommitdiffstats
path: root/drivers/platform/x86/dell/dcdbas.c
blob: a60e350563875f6b8ac14fbdfdbe143a0414b700 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  dcdbas.c: Dell Systems Management Base Driver
 *
 *  The Dell Systems Management Base Driver provides a sysfs interface for
 *  systems management software to perform System Management Interrupts (SMIs)
 *  and Host Control Actions (power cycle or power off after OS shutdown) on
 *  Dell systems.
 *
 *  See Documentation/userspace-api/dcdbas.rst for more information.
 *
 *  Copyright (C) 1995-2006 Dell Inc.
 */

#include <linux/platform_device.h>
#include <linux/acpi.h>
#include <linux/dma-mapping.h>
#include <linux/dmi.h>
#include <linux/errno.h>
#include <linux/cpu.h>
#include <linux/gfp.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mc146818rtc.h>
#include <linux/module.h>
#include <linux/reboot.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/mutex.h>

#include "dcdbas.h"

#define DRIVER_NAME		"dcdbas"
#define DRIVER_VERSION		"5.6.0-3.4"
#define DRIVER_DESCRIPTION	"Dell Systems Management Base Driver"

static struct platform_device *dcdbas_pdev;

static unsigned long max_smi_data_buf_size = MAX_SMI_DATA_BUF_SIZE;
static DEFINE_MUTEX(smi_data_lock);
static u8 *bios_buffer;
static struct smi_buffer smi_buf;

static unsigned int host_control_action;
static unsigned int host_control_smi_type;
static unsigned int host_control_on_shutdown;

static bool wsmt_enabled;

int dcdbas_smi_alloc(struct smi_buffer *smi_buffer, unsigned long size)
{
	smi_buffer->virt = dma_alloc_coherent(&dcdbas_pdev->dev, size,
					      &smi_buffer->dma, GFP_KERNEL);
	if (!smi_buffer->virt) {
		dev_dbg(&dcdbas_pdev->dev,
			"%s: failed to allocate memory size %lu\n",
			__func__, size);
		return -ENOMEM;
	}
	smi_buffer->size = size;

	dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
		__func__, (u32)smi_buffer->dma, smi_buffer->size);

	return 0;
}
EXPORT_SYMBOL_GPL(dcdbas_smi_alloc);

void dcdbas_smi_free(struct smi_buffer *smi_buffer)
{
	if (!smi_buffer->virt)
		return;

	dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
		__func__, (u32)smi_buffer->dma, smi_buffer->size);
	dma_free_coherent(&dcdbas_pdev->dev, smi_buffer->size,
			  smi_buffer->virt, smi_buffer->dma);
	smi_buffer->virt = NULL;
	smi_buffer->dma = 0;
	smi_buffer->size = 0;
}
EXPORT_SYMBOL_GPL(dcdbas_smi_free);

/**
 * smi_data_buf_free: free SMI data buffer
 */
static void smi_data_buf_free(void)
{
	if (!smi_buf.virt || wsmt_enabled)
		return;

	dcdbas_smi_free(&smi_buf);
}

/**
 * smi_data_buf_realloc: grow SMI data buffer if needed
 */
static int smi_data_buf_realloc(unsigned long size)
{
	struct smi_buffer tmp;
	int ret;

	if (smi_buf.size >= size)
		return 0;

	if (size > max_smi_data_buf_size)
		return -EINVAL;

	/* new buffer is needed */
	ret = dcdbas_smi_alloc(&tmp, size);
	if (ret)
		return ret;

	/* memory zeroed by dma_alloc_coherent */
	if (smi_buf.virt)
		memcpy(tmp.virt, smi_buf.virt, smi_buf.size);

	/* free any existing buffer */
	smi_data_buf_free();

	/* set up new buffer for use */
	smi_buf = tmp;

	return 0;
}

static ssize_t smi_data_buf_phys_addr_show(struct device *dev,
					   struct device_attribute *attr,
					   char *buf)
{
	return sprintf(buf, "%x\n", (u32)smi_buf.dma);
}

static ssize_t smi_data_buf_size_show(struct device *dev,
				      struct device_attribute *attr,
				      char *buf)
{
	return sprintf(buf, "%lu\n", smi_buf.size);
}

static ssize_t smi_data_buf_size_store(struct device *dev,
				       struct device_attribute *attr,
				       const char *buf, size_t count)
{
	unsigned long buf_size;
	ssize_t ret;

	buf_size = simple_strtoul(buf, NULL, 10);

	/* make sure SMI data buffer is at least buf_size */
	mutex_lock(&smi_data_lock);
	ret = smi_data_buf_realloc(buf_size);
	mutex_unlock(&smi_data_lock);
	if (ret)
		return ret;

	return count;
}

static ssize_t smi_data_read(struct file *filp, struct kobject *kobj,
			     struct bin_attribute *bin_attr,
			     char *buf, loff_t pos, size_t count)
{
	ssize_t ret;

	mutex_lock(&smi_data_lock);
	ret = memory_read_from_buffer(buf, count, &pos, smi_buf.virt,
					smi_buf.size);
	mutex_unlock(&smi_data_lock);
	return ret;
}

static ssize_t smi_data_write(struct file *filp, struct kobject *kobj,
			      struct bin_attribute *bin_attr,
			      char *buf, loff_t pos, size_t count)
{
	ssize_t ret;

	if ((pos + count) > max_smi_data_buf_size)
		return -EINVAL;

	mutex_lock(&smi_data_lock);

	ret = smi_data_buf_realloc(pos + count);
	if (ret)
		goto out;

	memcpy(smi_buf.virt + pos, buf, count);
	ret = count;
out:
	mutex_unlock(&smi_data_lock);
	return ret;
}

static ssize_t host_control_action_show(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	return sprintf(buf, "%u\n", host_control_action);
}

static ssize_t host_control_action_store(struct device *dev,
					 struct device_attribute *attr,
					 const char *buf, size_t count)
{
	ssize_t ret;

	/* make sure buffer is available for host control command */
	mutex_lock(&smi_data_lock);
	ret = smi_data_buf_realloc(sizeof(struct apm_cmd));
	mutex_unlock(&smi_data_lock);
	if (ret)
		return ret;

	host_control_action = simple_strtoul(buf, NULL, 10);
	return count;
}

static ssize_t host_control_smi_type_show(struct device *dev,
					  struct device_attribute *attr,
					  char *buf)
{
	return sprintf(buf, "%u\n", host_control_smi_type);
}

static ssize_t host_control_smi_type_store(struct device *dev,
					   struct device_attribute *attr,
					   const char *buf, size_t count)
{
	host_control_smi_type = simple_strtoul(buf, NULL, 10);
	return count;
}

static ssize_t host_control_on_shutdown_show(struct device *dev,
					     struct device_attribute *attr,
					     char *buf)
{
	return sprintf(buf, "%u\n", host_control_on_shutdown);
}

static ssize_t host_control_on_shutdown_store(struct device *dev,
					      struct device_attribute *attr,
					      const char *buf, size_t count)
{
	host_control_on_shutdown = simple_strtoul(buf, NULL, 10);
	return count;
}

static int raise_smi(void *par)
{
	struct smi_cmd *smi_cmd = par;

	if (smp_processor_id() != 0) {
		dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0\n",
			__func__);
		return -EBUSY;
	}

	/* generate SMI */
	/* inb to force posted write through and make SMI happen now */
	asm volatile (
		"outb %b0,%w1\n"
		"inb %w1"
		: /* no output args */
		: "a" (smi_cmd->command_code),
		  "d" (smi_cmd->command_address),
		  "b" (smi_cmd->ebx),
		  "c" (smi_cmd->ecx)
		: "memory"
	);

	return 0;
}
/**
 * dcdbas_smi_request: generate SMI request
 *
 * Called with smi_data_lock.
 */
int dcdbas_smi_request(struct smi_cmd *smi_cmd)
{
	int ret;

	if (smi_cmd->magic != SMI_CMD_MAGIC) {
		dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",
			 __func__);
		return -EBADR;
	}

	/* SMI requires CPU 0 */
	cpus_read_lock();
	ret = smp_call_on_cpu(0, raise_smi, smi_cmd, true);
	cpus_read_unlock();

	return ret;
}
EXPORT_SYMBOL(dcdbas_smi_request);

/**
 * smi_request_store:
 *
 * The valid values are:
 * 0: zero SMI data buffer
 * 1: generate calling interface SMI
 * 2: generate raw SMI
 *
 * User application writes smi_cmd to smi_data before telling driver
 * to generate SMI.
 */
static ssize_t smi_request_store(struct device *dev,
				 struct device_attribute *attr,
				 const char *buf, size_t count)
{
	struct smi_cmd *smi_cmd;
	unsigned long val = simple_strtoul(buf, NULL, 10);
	ssize_t ret;

	mutex_lock(&smi_data_lock);

	if (smi_buf.size < sizeof(struct smi_cmd)) {
		ret = -ENODEV;
		goto out;
	}
	smi_cmd = (struct smi_cmd *)smi_buf.virt;

	switch (val) {
	case 2:
		/* Raw SMI */
		ret = dcdbas_smi_request(smi_cmd);
		if (!ret)
			ret = count;
		break;
	case 1:
		/*
		 * Calling Interface SMI
		 *
		 * Provide physical address of command buffer field within
		 * the struct smi_cmd to BIOS.
		 *
		 * Because the address that smi_cmd (smi_buf.virt) points to
		 * will be from memremap() of a non-memory address if WSMT
		 * is present, we can't use virt_to_phys() on smi_cmd, so
		 * we have to use the physical address that was saved when
		 * the virtual address for smi_cmd was received.
		 */
		smi_cmd->ebx = (u32)smi_buf.dma +
				offsetof(struct smi_cmd, command_buffer);
		ret = dcdbas_smi_request(smi_cmd);
		if (!ret)
			ret = count;
		break;
	case 0:
		memset(smi_buf.virt, 0, smi_buf.size);
		ret = count;
		break;
	default:
		ret = -EINVAL;
		break;
	}

out:
	mutex_unlock(&smi_data_lock);
	return ret;
}

/**
 * host_control_smi: generate host control SMI
 *
 * Caller must set up the host control command in smi_buf.virt.
 */
static int host_control_smi(void)
{
	struct apm_cmd *apm_cmd;
	u8 *data;
	unsigned long flags;
	u32 num_ticks;
	s8 cmd_status;
	u8 index;

	apm_cmd = (struct apm_cmd *)smi_buf.virt;
	apm_cmd->status = ESM_STATUS_CMD_UNSUCCESSFUL;

	switch (host_control_smi_type) {
	case HC_SMITYPE_TYPE1:
		spin_lock_irqsave(&rtc_lock, flags);
		/* write SMI data buffer physical address */
		data = (u8 *)&smi_buf.dma;
		for (index = PE1300_CMOS_CMD_STRUCT_PTR;
		     index < (PE1300_CMOS_CMD_STRUCT_PTR + 4);
		     index++, data++) {
			outb(index,
			     (CMOS_BASE_PORT + CMOS_PAGE2_INDEX_PORT_PIIX4));
			outb(*data,
			     (CMOS_BASE_PORT + CMOS_PAGE2_DATA_PORT_PIIX4));
		}

		/* first set status to -1 as called by spec */
		cmd_status = ESM_STATUS_CMD_UNSUCCESSFUL;
		outb((u8) cmd_status, PCAT_APM_STATUS_PORT);

		/* generate SMM call */
		outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
		spin_unlock_irqrestore(&rtc_lock, flags);

		/* wait a few to see if it executed */
		num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
		while ((s8)inb(PCAT_APM_STATUS_PORT) == ESM_STATUS_CMD_UNSUCCESSFUL) {
			num_ticks--;
			if (num_ticks == EXPIRED_TIMER)
				return -ETIME;
		}
		break;

	case HC_SMITYPE_TYPE2:
	case HC_SMITYPE_TYPE3:
		spin_lock_irqsave(&rtc_lock, flags);
		/* write SMI data buffer physical address */
		data = (u8 *)&smi_buf.dma;
		for (index = PE1400_CMOS_CMD_STRUCT_PTR;
		     index < (PE1400_CMOS_CMD_STRUCT_PTR + 4);
		     index++, data++) {
			outb(index, (CMOS_BASE_PORT + CMOS_PAGE1_INDEX_PORT));
			outb(*data, (CMOS_BASE_PORT + CMOS_PAGE1_DATA_PORT));
		}

		/* generate SMM call */
		if (host_control_smi_type == HC_SMITYPE_TYPE3)
			outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
		else
			outb(ESM_APM_CMD, PE1400_APM_CONTROL_PORT);

		/* restore RTC index pointer since it was written to above */
		CMOS_READ(RTC_REG_C);
		spin_unlock_irqrestore(&rtc_lock, flags);

		/* read control port back to serialize write */
		cmd_status = inb(PE1400_APM_CONTROL_PORT);

		/* wait a few to see if it executed */
		num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
		while (apm_cmd->status == ESM_STATUS_CMD_UNSUCCESSFUL) {
			num_ticks--;
			if (num_ticks == EXPIRED_TIMER)
				return -ETIME;
		}
		break;

	default:
		dev_dbg(&dcdbas_pdev->dev, "%s: invalid SMI type %u\n",
			__func__, host_control_smi_type);
		return -ENOSYS;
	}

	return 0;
}

/**
 * dcdbas_host_control: initiate host control
 *
 * This function is called by the driver after the system has
 * finished shutting down if the user application specified a
 * host control action to perform on shutdown.  It is safe to
 * use smi_buf.virt at this point because the system has finished
 * shutting down and no userspace apps are running.
 */
static void dcdbas_host_control(void)
{
	struct apm_cmd *apm_cmd;
	u8 action;

	if (host_control_action == HC_ACTION_NONE)
		return;

	action = host_control_action;
	host_control_action = HC_ACTION_NONE;

	if (!smi_buf.virt) {
		dev_dbg(&dcdbas_pdev->dev, "%s: no SMI buffer\n", __func__);
		return;
	}

	if (smi_buf.size < sizeof(struct apm_cmd)) {
		dev_dbg(&dcdbas_pdev->dev, "%s: SMI buffer too small\n",
			__func__);
		return;
	}

	apm_cmd = (struct apm_cmd *)smi_buf.virt;

	/* power off takes precedence */
	if (action & HC_ACTION_HOST_CONTROL_POWEROFF) {
		apm_cmd->command = ESM_APM_POWER_CYCLE;
		apm_cmd->reserved = 0;
		*((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 0;
		host_control_smi();
	} else if (action & HC_ACTION_HOST_CONTROL_POWERCYCLE) {
		apm_cmd->command = ESM_APM_POWER_CYCLE;
		apm_cmd->reserved = 0;
		*((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 20;
		host_control_smi();
	}
}

/* WSMT */

static u8 checksum(u8 *buffer, u8 length)
{
	u8 sum = 0;
	u8 *end = buffer + length;

	while (buffer < end)
		sum += *buffer++;
	return sum;
}

static inline struct smm_eps_table *check_eps_table(u8 *addr)
{
	struct smm_eps_table *eps = (struct smm_eps_table *)addr;

	if (strncmp(eps->smm_comm_buff_anchor, SMM_EPS_SIG, 4) != 0)
		return NULL;

	if (checksum(addr, eps->length) != 0)
		return NULL;

	return eps;
}

static int dcdbas_check_wsmt(void)
{
	const struct dmi_device *dev = NULL;
	struct acpi_table_wsmt *wsmt = NULL;
	struct smm_eps_table *eps = NULL;
	u64 bios_buf_paddr;
	u64 remap_size;
	u8 *addr;

	acpi_get_table(ACPI_SIG_WSMT, 0, (struct acpi_table_header **)&wsmt);
	if (!wsmt)
		return 0;

	/* Check if WSMT ACPI table shows that protection is enabled */
	if (!(wsmt->protection_flags & ACPI_WSMT_FIXED_COMM_BUFFERS) ||
	    !(wsmt->protection_flags & ACPI_WSMT_COMM_BUFFER_NESTED_PTR_PROTECTION))
		return 0;

	/*
	 * BIOS could provide the address/size of the protected buffer
	 * in an SMBIOS string or in an EPS structure in 0xFxxxx.
	 */

	/* Check SMBIOS for buffer address */
	while ((dev = dmi_find_device(DMI_DEV_TYPE_OEM_STRING, NULL, dev)))
		if (sscanf(dev->name, "30[%16llx;%8llx]", &bios_buf_paddr,
		    &remap_size) == 2)
			goto remap;

	/* Scan for EPS (entry point structure) */
	for (addr = (u8 *)__va(0xf0000);
	     addr < (u8 *)__va(0x100000 - sizeof(struct smm_eps_table));
	     addr += 16) {
		eps = check_eps_table(addr);
		if (eps)
			break;
	}

	if (!eps) {
		dev_dbg(&dcdbas_pdev->dev, "found WSMT, but no firmware buffer found\n");
		return -ENODEV;
	}
	bios_buf_paddr = eps->smm_comm_buff_addr;
	remap_size = eps->num_of_4k_pages * PAGE_SIZE;

remap:
	/*
	 * Get physical address of buffer and map to virtual address.
	 * Table gives size in 4K pages, regardless of actual system page size.
	 */
	if (upper_32_bits(bios_buf_paddr + 8)) {
		dev_warn(&dcdbas_pdev->dev, "found WSMT, but buffer address is above 4GB\n");
		return -EINVAL;
	}
	/*
	 * Limit remap size to MAX_SMI_DATA_BUF_SIZE + 8 (since the first 8
	 * bytes are used for a semaphore, not the data buffer itself).
	 */
	if (remap_size > MAX_SMI_DATA_BUF_SIZE + 8)
		remap_size = MAX_SMI_DATA_BUF_SIZE + 8;

	bios_buffer = memremap(bios_buf_paddr, remap_size, MEMREMAP_WB);
	if (!bios_buffer) {
		dev_warn(&dcdbas_pdev->dev, "found WSMT, but failed to map buffer\n");
		return -ENOMEM;
	}

	/* First 8 bytes is for a semaphore, not part of the smi_buf.virt */
	smi_buf.dma = bios_buf_paddr + 8;
	smi_buf.virt = bios_buffer + 8;
	smi_buf.size = remap_size - 8;
	max_smi_data_buf_size = smi_buf.size;
	wsmt_enabled = true;
	dev_info(&dcdbas_pdev->dev,
		 "WSMT found, using firmware-provided SMI buffer.\n");
	return 1;
}

/**
 * dcdbas_reboot_notify: handle reboot notification for host control
 */
static int dcdbas_reboot_notify(struct notifier_block *nb, unsigned long code,
				void *unused)
{
	switch (code) {
	case SYS_DOWN:
	case SYS_HALT:
	case SYS_POWER_OFF:
		if (host_control_on_shutdown) {
			/* firmware is going to perform host control action */
			printk(KERN_WARNING "Please wait for shutdown "
			       "action to complete...\n");
			dcdbas_host_control();
		}
		break;
	}

	return NOTIFY_DONE;
}

static struct notifier_block dcdbas_reboot_nb = {
	.notifier_call = dcdbas_reboot_notify,
	.next = NULL,
	.priority = INT_MIN
};

static DCDBAS_BIN_ATTR_RW(smi_data);

static struct bin_attribute *dcdbas_bin_attrs[] = {
	&bin_attr_smi_data,
	NULL
};

static DCDBAS_DEV_ATTR_RW(smi_data_buf_size);
static DCDBAS_DEV_ATTR_RO(smi_data_buf_phys_addr);
static DCDBAS_DEV_ATTR_WO(smi_request);
static DCDBAS_DEV_ATTR_RW(host_control_action);
static DCDBAS_DEV_ATTR_RW(host_control_smi_type);
static DCDBAS_DEV_ATTR_RW(host_control_on_shutdown);

static struct attribute *dcdbas_dev_attrs[] = {
	&dev_attr_smi_data_buf_size.attr,
	&dev_attr_smi_data_buf_phys_addr.attr,
	&dev_attr_smi_request.attr,
	&dev_attr_host_control_action.attr,
	&dev_attr_host_control_smi_type.attr,
	&dev_attr_host_control_on_shutdown.attr,
	NULL
};

static const struct attribute_group dcdbas_attr_group = {
	.attrs = dcdbas_dev_attrs,
	.bin_attrs = dcdbas_bin_attrs,
};

static int dcdbas_probe(struct platform_device *dev)
{
	int error;

	host_control_action = HC_ACTION_NONE;
	host_control_smi_type = HC_SMITYPE_NONE;

	dcdbas_pdev = dev;

	/* Check if ACPI WSMT table specifies protected SMI buffer address */
	error = dcdbas_check_wsmt();
	if (error < 0)
		return error;

	/*
	 * BIOS SMI calls require buffer addresses be in 32-bit address space.
	 * This is done by setting the DMA mask below.
	 */
	error = dma_set_coherent_mask(&dcdbas_pdev->dev, DMA_BIT_MASK(32));
	if (error)
		return error;

	error = sysfs_create_group(&dev->dev.kobj, &dcdbas_attr_group);
	if (error)
		return error;

	register_reboot_notifier(&dcdbas_reboot_nb);

	dev_info(&dev->dev, "%s (version %s)\n",
		 DRIVER_DESCRIPTION, DRIVER_VERSION);

	return 0;
}

static void dcdbas_remove(struct platform_device *dev)
{
	unregister_reboot_notifier(&dcdbas_reboot_nb);
	sysfs_remove_group(&dev->dev.kobj, &dcdbas_attr_group);
}

static struct platform_driver dcdbas_driver = {
	.driver		= {
		.name	= DRIVER_NAME,
	},
	.probe		= dcdbas_probe,
	.remove_new	= dcdbas_remove,
};

static const struct platform_device_info dcdbas_dev_info __initconst = {
	.name		= DRIVER_NAME,
	.id		= PLATFORM_DEVID_NONE,
	.dma_mask	= DMA_BIT_MASK(32),
};

static struct platform_device *dcdbas_pdev_reg;

/**
 * dcdbas_init: initialize driver
 */
static int __init dcdbas_init(void)
{
	int error;

	error = platform_driver_register(&dcdbas_driver);
	if (error)
		return error;

	dcdbas_pdev_reg = platform_device_register_full(&dcdbas_dev_info);
	if (IS_ERR(dcdbas_pdev_reg)) {
		error = PTR_ERR(dcdbas_pdev_reg);
		goto err_unregister_driver;
	}

	return 0;

 err_unregister_driver:
	platform_driver_unregister(&dcdbas_driver);
	return error;
}

/**
 * dcdbas_exit: perform driver cleanup
 */
static void __exit dcdbas_exit(void)
{
	/*
	 * make sure functions that use dcdbas_pdev are called
	 * before platform_device_unregister
	 */
	unregister_reboot_notifier(&dcdbas_reboot_nb);

	/*
	 * We have to free the buffer here instead of dcdbas_remove
	 * because only in module exit function we can be sure that
	 * all sysfs attributes belonging to this module have been
	 * released.
	 */
	if (dcdbas_pdev)
		smi_data_buf_free();
	if (bios_buffer)
		memunmap(bios_buffer);
	platform_device_unregister(dcdbas_pdev_reg);
	platform_driver_unregister(&dcdbas_driver);
}

subsys_initcall_sync(dcdbas_init);
module_exit(dcdbas_exit);

MODULE_DESCRIPTION(DRIVER_DESCRIPTION " (version " DRIVER_VERSION ")");
MODULE_VERSION(DRIVER_VERSION);
MODULE_AUTHOR("Dell Inc.");
MODULE_LICENSE("GPL");
/* Any System or BIOS claiming to be by Dell */
MODULE_ALIAS("dmi:*:[bs]vnD[Ee][Ll][Ll]*:*");