summaryrefslogtreecommitdiffstats
path: root/drivers/platform/x86/dell-smbios.c
blob: b1038325a3fcdf74f5d8ca8c7c130142b3787a9d (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
/*
 *  Common functions for kernel modules using Dell SMBIOS
 *
 *  Copyright (c) Red Hat <mjg@redhat.com>
 *  Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@gmail.com>
 *  Copyright (c) 2014 Pali Rohár <pali.rohar@gmail.com>
 *
 *  Based on documentation in the libsmbios package:
 *  Copyright (C) 2005-2014 Dell Inc.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/dmi.h>
#include <linux/gfp.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/io.h>
#include "../../firmware/dcdbas.h"
#include "dell-smbios.h"

struct calling_interface_structure {
	struct dmi_header header;
	u16 cmdIOAddress;
	u8 cmdIOCode;
	u32 supportedCmds;
	struct calling_interface_token tokens[];
} __packed;

struct calling_interface_buffer *buffer;
EXPORT_SYMBOL_GPL(buffer);
static DEFINE_MUTEX(buffer_mutex);

static int da_command_address;
static int da_command_code;
static int da_num_tokens;
struct calling_interface_token *da_tokens;
EXPORT_SYMBOL_GPL(da_tokens);

void dell_smbios_get_buffer(void)
{
	mutex_lock(&buffer_mutex);
	dell_smbios_clear_buffer();
}
EXPORT_SYMBOL_GPL(dell_smbios_get_buffer);

void dell_smbios_clear_buffer(void)
{
	memset(buffer, 0, sizeof(struct calling_interface_buffer));
}
EXPORT_SYMBOL_GPL(dell_smbios_clear_buffer);

void dell_smbios_release_buffer(void)
{
	mutex_unlock(&buffer_mutex);
}
EXPORT_SYMBOL_GPL(dell_smbios_release_buffer);

struct calling_interface_buffer *
dell_smbios_send_request(struct calling_interface_buffer *buffer,
			 int class, int select)
{
	struct smi_cmd command;

	command.magic = SMI_CMD_MAGIC;
	command.command_address = da_command_address;
	command.command_code = da_command_code;
	command.ebx = virt_to_phys(buffer);
	command.ecx = 0x42534931;

	buffer->class = class;
	buffer->select = select;

	dcdbas_smi_request(&command);

	return buffer;
}
EXPORT_SYMBOL_GPL(dell_smbios_send_request);

int find_token_id(int tokenid)
{
	int i;

	for (i = 0; i < da_num_tokens; i++) {
		if (da_tokens[i].tokenID == tokenid)
			return i;
	}

	return -1;
}
EXPORT_SYMBOL_GPL(find_token_id);

int find_token_location(int tokenid)
{
	int id;

	id = find_token_id(tokenid);
	if (id == -1)
		return -1;

	return da_tokens[id].location;
}
EXPORT_SYMBOL_GPL(find_token_location);

static void __init parse_da_table(const struct dmi_header *dm)
{
	/* Final token is a terminator, so we don't want to copy it */
	int tokens = (dm->length-11)/sizeof(struct calling_interface_token)-1;
	struct calling_interface_token *new_da_tokens;
	struct calling_interface_structure *table =
		container_of(dm, struct calling_interface_structure, header);

	/* 4 bytes of table header, plus 7 bytes of Dell header, plus at least
	   6 bytes of entry */

	if (dm->length < 17)
		return;

	da_command_address = table->cmdIOAddress;
	da_command_code = table->cmdIOCode;

	new_da_tokens = krealloc(da_tokens, (da_num_tokens + tokens) *
				 sizeof(struct calling_interface_token),
				 GFP_KERNEL);

	if (!new_da_tokens)
		return;
	da_tokens = new_da_tokens;

	memcpy(da_tokens+da_num_tokens, table->tokens,
	       sizeof(struct calling_interface_token) * tokens);

	da_num_tokens += tokens;
}

static void __init find_tokens(const struct dmi_header *dm, void *dummy)
{
	switch (dm->type) {
	case 0xd4: /* Indexed IO */
	case 0xd5: /* Protected Area Type 1 */
	case 0xd6: /* Protected Area Type 2 */
		break;
	case 0xda: /* Calling interface */
		parse_da_table(dm);
		break;
	}
}

static int __init dell_smbios_init(void)
{
	int ret;

	dmi_walk(find_tokens, NULL);

	if (!da_tokens)  {
		pr_info("Unable to find dmi tokens\n");
		return -ENODEV;
	}

	/*
	 * Allocate buffer below 4GB for SMI data--only 32-bit physical addr
	 * is passed to SMI handler.
	 */
	buffer = (void *)__get_free_page(GFP_KERNEL | GFP_DMA32);
	if (!buffer) {
		ret = -ENOMEM;
		goto fail_buffer;
	}

	return 0;

fail_buffer:
	kfree(da_tokens);
	return ret;
}

static void __exit dell_smbios_exit(void)
{
	kfree(da_tokens);
	free_page((unsigned long)buffer);
}

subsys_initcall(dell_smbios_init);
module_exit(dell_smbios_exit);

MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
MODULE_AUTHOR("Gabriele Mazzotta <gabriele.mzt@gmail.com>");
MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
MODULE_DESCRIPTION("Common functions for kernel modules using Dell SMBIOS");
MODULE_LICENSE("GPL");