tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * mtdram - a test mtd device
3 * Author: Alexander Larsson <alex@cendio.se>
4 *
5 * Copyright (c) 1999 Alexander Larsson <alex@cendio.se>
6 * Copyright (c) 2005 Joern Engel <joern@wh.fh-wedel.de>
7 *
8 * This code is GPL
9 *
10 */
11
12#include <linux/module.h>
13#include <linux/slab.h>
14#include <linux/ioport.h>
15#include <linux/vmalloc.h>
16#include <linux/init.h>
17#include <linux/mtd/mtd.h>
18#include <linux/mtd/mtdram.h>
19
20static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE;
21static unsigned long erase_size = CONFIG_MTDRAM_ERASE_SIZE;
22static unsigned long writebuf_size = 64;
23#define MTDRAM_TOTAL_SIZE (total_size * 1024)
24#define MTDRAM_ERASE_SIZE (erase_size * 1024)
25
26#ifdef MODULE
27module_param(total_size, ulong, 0);
28MODULE_PARM_DESC(total_size, "Total device size in KiB");
29module_param(erase_size, ulong, 0);
30MODULE_PARM_DESC(erase_size, "Device erase block size in KiB");
31module_param(writebuf_size, ulong, 0);
32MODULE_PARM_DESC(writebuf_size, "Device write buf size in Bytes (Default: 64)");
33#endif
34
35// We could store these in the mtd structure, but we only support 1 device..
36static struct mtd_info *mtd_info;
37
38static int check_offs_len(struct mtd_info *mtd, loff_t ofs, uint64_t len)
39{
40 int ret = 0;
41
42 /* Start address must align on block boundary */
43 if (mtd_mod_by_eb(ofs, mtd)) {
44 pr_debug("%s: unaligned address\n", __func__);
45 ret = -EINVAL;
46 }
47
48 /* Length must align on block boundary */
49 if (mtd_mod_by_eb(len, mtd)) {
50 pr_debug("%s: length not block aligned\n", __func__);
51 ret = -EINVAL;
52 }
53
54 return ret;
55}
56
57static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
58{
59 if (check_offs_len(mtd, instr->addr, instr->len))
60 return -EINVAL;
61 memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
62 instr->state = MTD_ERASE_DONE;
63 mtd_erase_callback(instr);
64 return 0;
65}
66
67static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
68 size_t *retlen, void **virt, resource_size_t *phys)
69{
70 *virt = mtd->priv + from;
71 *retlen = len;
72 return 0;
73}
74
75static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
76{
77 return 0;
78}
79
80/*
81 * Allow NOMMU mmap() to directly map the device (if not NULL)
82 * - return the address to which the offset maps
83 * - return -ENOSYS to indicate refusal to do the mapping
84 */
85static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
86 unsigned long len,
87 unsigned long offset,
88 unsigned long flags)
89{
90 return (unsigned long) mtd->priv + offset;
91}
92
93static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
94 size_t *retlen, u_char *buf)
95{
96 memcpy(buf, mtd->priv + from, len);
97 *retlen = len;
98 return 0;
99}
100
101static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
102 size_t *retlen, const u_char *buf)
103{
104 memcpy((char *)mtd->priv + to, buf, len);
105 *retlen = len;
106 return 0;
107}
108
109static void __exit cleanup_mtdram(void)
110{
111 if (mtd_info) {
112 mtd_device_unregister(mtd_info);
113 vfree(mtd_info->priv);
114 kfree(mtd_info);
115 }
116}
117
118int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
119 unsigned long size, const char *name)
120{
121 memset(mtd, 0, sizeof(*mtd));
122
123 /* Setup the MTD structure */
124 mtd->name = name;
125 mtd->type = MTD_RAM;
126 mtd->flags = MTD_CAP_RAM;
127 mtd->size = size;
128 mtd->writesize = 1;
129 mtd->writebufsize = writebuf_size;
130 mtd->erasesize = MTDRAM_ERASE_SIZE;
131 mtd->priv = mapped_address;
132
133 mtd->owner = THIS_MODULE;
134 mtd->_erase = ram_erase;
135 mtd->_point = ram_point;
136 mtd->_unpoint = ram_unpoint;
137 mtd->_get_unmapped_area = ram_get_unmapped_area;
138 mtd->_read = ram_read;
139 mtd->_write = ram_write;
140
141 if (mtd_device_register(mtd, NULL, 0))
142 return -EIO;
143
144 return 0;
145}
146
147static int __init init_mtdram(void)
148{
149 void *addr;
150 int err;
151
152 if (!total_size)
153 return -EINVAL;
154
155 /* Allocate some memory */
156 mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
157 if (!mtd_info)
158 return -ENOMEM;
159
160 addr = vmalloc(MTDRAM_TOTAL_SIZE);
161 if (!addr) {
162 kfree(mtd_info);
163 mtd_info = NULL;
164 return -ENOMEM;
165 }
166 err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
167 if (err) {
168 vfree(addr);
169 kfree(mtd_info);
170 mtd_info = NULL;
171 return err;
172 }
173 memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
174 return err;
175}
176
177module_init(init_mtdram);
178module_exit(cleanup_mtdram);
179
180MODULE_LICENSE("GPL");
181MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
182MODULE_DESCRIPTION("Simulated MTD driver for testing");