aboutsummaryrefslogtreecommitdiffstats
path: root/src/include/region.h
blob: 82db85499419128da1cd127e4751534e211576ca (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
/*
 * This file is part of the coreboot project.
 *
 * Copyright 2015 Google Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc.
 */

#ifndef _REGION_H_
#define _REGION_H_

#include <stdint.h>
#include <stddef.h>
#include <mem_pool.h>

/*
 * Region support.
 *
 * Regions are intended to abstract away the access mechanisms for blocks of
 * data. This could be SPI, eMMC, or a memory region as the backing store.
 * They are accessed through a region_device.  Subregions can be made by
 * chaining together multiple region_devices.
 */

struct region_device;

/*
 * Returns NULL on error otherwise a buffer is returned with the conents of
 * the requested data at offset of size.
 */
void *rdev_mmap(const struct region_device *rd, size_t offset, size_t size);

/* Unmap a previously mapped area. Returns 0 on success, < 0 on error. */
int rdev_munmap(const struct region_device *rd, void *mapping);

/*
 * Returns < 0 on error otherwise returns size of data read at provided
 * offset filling in the buffer passed.
 */
ssize_t rdev_readat(const struct region_device *rd, void *b, size_t offset,
			size_t size);


/****************************************
 *  Implementation of a region device   *
 ****************************************/

/*
 * Create a child region of the parent provided the sub-region is within
 * the parent's region. Returns < 0 on error otherwise 0 on success. Note
 * that the child device only calls through the parent's operations.
 */
int rdev_chain(struct region_device *child, const struct region_device *parent,
		size_t offset, size_t size);


/* A region_device operations. */
struct region_device_ops {
	void *(*mmap)(const struct region_device *, size_t, size_t);
	int (*munmap)(const struct region_device *, void *);
	ssize_t (*readat)(const struct region_device *, void *, size_t, size_t);
};

struct region {
	size_t offset;
	size_t size;
};

struct region_device {
	const struct region_device *root;
	const struct region_device_ops *ops;
	struct region region;
};

#define REGION_DEV_INIT(ops_, offset_, size_)		\
	{						\
		.root = NULL,				\
		.ops = (ops_),				\
		.region = {				\
			.offset = (offset_),		\
			.size = (size_),		\
		},					\
	}

static inline size_t region_offset(const struct region *r)
{
	return r->offset;
}

static inline size_t region_sz(const struct region *r)
{
	return r->size;
}

static inline size_t region_device_sz(const struct region_device *rdev)
{
	return region_sz(&rdev->region);
}

static inline size_t region_device_offset(const struct region_device *rdev)
{
	return region_offset(&rdev->region);
}

/* Memory map entire region device. Same semantics as rdev_mmap() above. */
static inline void *rdev_mmap_full(const struct region_device *rd)
{
	return rdev_mmap(rd, 0, region_device_sz(rd));
}

struct mem_region_device {
	char *base;
	struct region_device rdev;
};

/* Iniitalize at runtime a mem_region_device. This would be used when
 * the base and size are dynamic or can't be known during linking. */
void mem_region_device_init(struct mem_region_device *mdev, void *base,
				size_t size);

extern const struct region_device_ops mem_rdev_ops;

/* Statically initialize mem_region_device. */
#define MEM_REGION_DEV_INIT(base_, size_)				\
	{								\
		.base = (void *)(base_),				\
		.rdev = REGION_DEV_INIT(&mem_rdev_ops, 0, (size_)),	\
	}

struct mmap_helper_region_device {
	struct mem_pool pool;
	struct region_device rdev;
};

#define MMAP_HELPER_REGION_INIT(ops_, offset_, size_) \
	{								\
		.rdev = REGION_DEV_INIT((ops_), (offset_), (size_)),	\
	}

void mmap_helper_device_init(struct mmap_helper_region_device *mdev,
				void *cache, size_t cache_size);

void *mmap_helper_rdev_mmap(const struct region_device *, size_t, size_t);
int mmap_helper_rdev_munmap(const struct region_device *, void *);

#endif /* _REGION_H_ */