aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/firmware/memmap.c
blob: d5ea8a68d338ef80996d20dd0bbbf4e27d3fafc0 (plain) (blame)
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
/*
 * linux/drivers/firmware/memmap.c
 *  Copyright (C) 2008 SUSE LINUX Products GmbH
 *  by Bernhard Walle <bernhard.walle@gmx.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License v2.0 as published by
 * the Free Software Foundation
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/string.h>
#include <linux/firmware-map.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/bootmem.h>

/*
 * Data types ------------------------------------------------------------------
 */

/*
 * Firmware map entry. Because firmware memory maps are flat and not
 * hierarchical, it's ok to organise them in a linked list. No parent
 * information is necessary as for the resource tree.
 */
struct firmware_map_entry {
	/*
	 * start and end must be u64 rather than resource_size_t, because e820
	 * resources can lie at addresses above 4G.
	 */
	u64			start;	/* start of the memory range */
	u64			end;	/* end of the memory range (incl.) */
	const char		*type;	/* type of the memory range */
	struct list_head	list;	/* entry for the linked list */
	struct kobject		kobj;   /* kobject for each entry */
};

/*
 * Forward declarations --------------------------------------------------------
 */
static ssize_t memmap_attr_show(struct kobject *kobj,
				struct attribute *attr, char *buf);
static ssize_t start_show(struct firmware_map_entry *entry, char *buf);
static ssize_t end_show(struct firmware_map_entry *entry, char *buf);
static ssize_t type_show(struct firmware_map_entry *entry, char *buf);

/*
 * Static data -----------------------------------------------------------------
 */

struct memmap_attribute {
	struct attribute attr;
	ssize_t (*show)(struct firmware_map_entry *entry, char *buf);
};

static struct memmap_attribute memmap_start_attr = __ATTR_RO(start);
static struct memmap_attribute memmap_end_attr   = __ATTR_RO(end);
static struct memmap_attribute memmap_type_attr  = __ATTR_RO(type);

/*
 * These are default attributes that are added for every memmap entry.
 */
static struct attribute *def_attrs[] = {
	&memmap_start_attr.attr,
	&memmap_end_attr.attr,
	&memmap_type_attr.attr,
	NULL
};

static struct sysfs_ops memmap_attr_ops = {
	.show = memmap_attr_show,
};

static struct kobj_type memmap_ktype = {
	.sysfs_ops	= &memmap_attr_ops,
	.default_attrs	= def_attrs,
};

/*
 * Registration functions ------------------------------------------------------
 */

/*
 * Firmware memory map entries. No locking is needed because the
 * firmware_map_add() and firmware_map_add_early() functions are called
 * in firmware initialisation code in one single thread of execution.
 */
static LIST_HEAD(map_entries);

/**
 * firmware_map_add_entry() - Does the real work to add a firmware memmap entry.
 * @start: Start of the memory range.
 * @end:   End of the memory range (inclusive).
 * @type:  Type of the memory range.
 * @entry: Pre-allocated (either kmalloc() or bootmem allocator), uninitialised
 *         entry.
 *
 * Common implementation of firmware_map_add() and firmware_map_add_early()
 * which expects a pre-allocated struct firmware_map_entry.
 **/
static int firmware_map_add_entry(u64 start, u64 end,
				  const char *type,
				  struct firmware_map_entry *entry)
{
	BUG_ON(start > end);

	entry->start = start;
	entry->end = end;
	entry->type = type;
	INIT_LIST_HEAD(&entry->list);
	kobject_init(&entry->kobj, &memmap_ktype);

	list_add_tail(&entry->list, &map_entries);

	return 0;
}

/**
 * firmware_map_add() - Adds a firmware mapping entry.
 * @start: Start of the memory range.
 * @end:   End of the memory range (inclusive).
 * @type:  Type of the memory range.
 *
 * This function uses kmalloc() for memory
 * allocation. Use firmware_map_add_early() if you want to use the bootmem
 * allocator.
 *
 * That function must be called before late_initcall.
 *
 * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 **/
int firmware_map_add(u64 start, u64 end, const char *type)
{
	struct firmware_map_entry *entry;

	entry = kmalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);
	if (!entry)
		return -ENOMEM;

	return firmware_map_add_entry(start, end, type, entry);
}

/**
 * firmware_map_add_early() - Adds a firmware mapping entry.
 * @start: Start of the memory range.
 * @end:   End of the memory range (inclusive).
 * @type:  Type of the memory range.
 *
 * Adds a firmware mapping entry. This function uses the bootmem allocator
 * for memory allocation. Use firmware_map_add() if you want to use kmalloc().
 *
 * That function must be called before late_initcall.
 *
 * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 **/
int __init firmware_map_add_early(u64 start, u64 end, const char *type)
{
	struct firmware_map_entry *entry;

	entry = alloc_bootmem_low(sizeof(struct firmware_map_entry));
	if (WARN_ON(!entry))
		return -ENOMEM;

	return firmware_map_add_entry(start, end, type, entry);
}

/*
 * Sysfs functions -------------------------------------------------------------
 */

static ssize_t start_show(struct firmware_map_entry *entry, char *buf)
{
	return snprintf(buf, PAGE_SIZE, "0x%llx\n",
		(unsigned long long)entry->start);
}

static ssize_t end_show(struct firmware_map_entry *entry, char *buf)
{
	return snprintf(buf, PAGE_SIZE, "0x%llx\n",
		(unsigned long long)entry->end);
}

static ssize_t type_show(struct firmware_map_entry *entry, char *buf)
{
	return snprintf(buf, PAGE_SIZE, "%s\n", entry->type);
}

#define to_memmap_attr(_attr) container_of(_attr, struct memmap_attribute, attr)
#define to_memmap_entry(obj) container_of(obj, struct firmware_map_entry, kobj)

static ssize_t memmap_attr_show(struct kobject *kobj,
				struct attribute *attr, char *buf)
{
	struct firmware_map_entry *entry = to_memmap_entry(kobj);
	struct memmap_attribute *memmap_attr = to_memmap_attr(attr);

	return memmap_attr->show(entry, buf);
}

/*
 * Initialises stuff and adds the entries in the map_entries list to
 * sysfs. Important is that firmware_map_add() and firmware_map_add_early()
 * must be called before late_initcall. That's just because that function
 * is called as late_initcall() function, which means that if you call
 * firmware_map_add() or firmware_map_add_early() afterwards, the entries
 * are not added to sysfs.
 */
static int __init memmap_init(void)
{
	int i = 0;
	struct firmware_map_entry *entry;
	struct kset *memmap_kset;

	memmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj);
	if (WARN_ON(!memmap_kset))
		return -ENOMEM;

	list_for_each_entry(entry, &map_entries, list) {
		entry->kobj.kset = memmap_kset;
		if (kobject_add(&entry->kobj, NULL, "%d", i++))
			kobject_put(&entry->kobj);
	}

	return 0;
}
late_initcall(memmap_init);