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
20 static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE;
21 static unsigned long erase_size = CONFIG_MTDRAM_ERASE_SIZE;
22 #define MTDRAM_TOTAL_SIZE (total_size * 1024)
23 #define MTDRAM_ERASE_SIZE (erase_size * 1024)
24
25 #ifdef MODULE
26 module_param(total_size, ulong, 0);
27 MODULE_PARM_DESC(total_size, "Total device size in KiB");
28 module_param(erase_size, ulong, 0);
29 MODULE_PARM_DESC(erase_size, "Device erase block size in KiB");
30 #endif
31
32 // We could store these in the mtd structure, but we only support 1 device..
33 static struct mtd_info *mtd_info;
34
check_offs_len(struct mtd_info * mtd,loff_t ofs,uint64_t len)35 static int check_offs_len(struct mtd_info *mtd, loff_t ofs, uint64_t len)
36 {
37 int ret = 0;
38
39 /* Start address must align on block boundary */
40 if (mtd_mod_by_eb(ofs, mtd)) {
41 pr_debug("%s: unaligned address\n", __func__);
42 ret = -EINVAL;
43 }
44
45 /* Length must align on block boundary */
46 if (mtd_mod_by_eb(len, mtd)) {
47 pr_debug("%s: length not block aligned\n", __func__);
48 ret = -EINVAL;
49 }
50
51 return ret;
52 }
53
ram_erase(struct mtd_info * mtd,struct erase_info * instr)54 static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
55 {
56 if (check_offs_len(mtd, instr->addr, instr->len))
57 return -EINVAL;
58 memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
59 instr->state = MTD_ERASE_DONE;
60 mtd_erase_callback(instr);
61 return 0;
62 }
63
ram_point(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,void ** virt,resource_size_t * phys)64 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
65 size_t *retlen, void **virt, resource_size_t *phys)
66 {
67 *virt = mtd->priv + from;
68 *retlen = len;
69 return 0;
70 }
71
ram_unpoint(struct mtd_info * mtd,loff_t from,size_t len)72 static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
73 {
74 return 0;
75 }
76
77 /*
78 * Allow NOMMU mmap() to directly map the device (if not NULL)
79 * - return the address to which the offset maps
80 * - return -ENOSYS to indicate refusal to do the mapping
81 */
ram_get_unmapped_area(struct mtd_info * mtd,unsigned long len,unsigned long offset,unsigned long flags)82 static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
83 unsigned long len,
84 unsigned long offset,
85 unsigned long flags)
86 {
87 return (unsigned long) mtd->priv + offset;
88 }
89
ram_read(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,u_char * buf)90 static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
91 size_t *retlen, u_char *buf)
92 {
93 memcpy(buf, mtd->priv + from, len);
94 *retlen = len;
95 return 0;
96 }
97
ram_write(struct mtd_info * mtd,loff_t to,size_t len,size_t * retlen,const u_char * buf)98 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
99 size_t *retlen, const u_char *buf)
100 {
101 memcpy((char *)mtd->priv + to, buf, len);
102 *retlen = len;
103 return 0;
104 }
105
cleanup_mtdram(void)106 static void __exit cleanup_mtdram(void)
107 {
108 if (mtd_info) {
109 mtd_device_unregister(mtd_info);
110 vfree(mtd_info->priv);
111 kfree(mtd_info);
112 }
113 }
114
mtdram_init_device(struct mtd_info * mtd,void * mapped_address,unsigned long size,const char * name)115 int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
116 unsigned long size, const char *name)
117 {
118 memset(mtd, 0, sizeof(*mtd));
119
120 /* Setup the MTD structure */
121 mtd->name = name;
122 mtd->type = MTD_RAM;
123 mtd->flags = MTD_CAP_RAM;
124 mtd->size = size;
125 mtd->writesize = 1;
126 mtd->writebufsize = 64; /* Mimic CFI NOR flashes */
127 mtd->erasesize = MTDRAM_ERASE_SIZE;
128 mtd->priv = mapped_address;
129
130 mtd->owner = THIS_MODULE;
131 mtd->_erase = ram_erase;
132 mtd->_point = ram_point;
133 mtd->_unpoint = ram_unpoint;
134 mtd->_get_unmapped_area = ram_get_unmapped_area;
135 mtd->_read = ram_read;
136 mtd->_write = ram_write;
137
138 if (mtd_device_register(mtd, NULL, 0))
139 return -EIO;
140
141 return 0;
142 }
143
init_mtdram(void)144 static int __init init_mtdram(void)
145 {
146 void *addr;
147 int err;
148
149 if (!total_size)
150 return -EINVAL;
151
152 /* Allocate some memory */
153 mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
154 if (!mtd_info)
155 return -ENOMEM;
156
157 addr = vmalloc(MTDRAM_TOTAL_SIZE);
158 if (!addr) {
159 kfree(mtd_info);
160 mtd_info = NULL;
161 return -ENOMEM;
162 }
163 err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
164 if (err) {
165 vfree(addr);
166 kfree(mtd_info);
167 mtd_info = NULL;
168 return err;
169 }
170 memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
171 return err;
172 }
173
174 module_init(init_mtdram);
175 module_exit(cleanup_mtdram);
176
177 MODULE_LICENSE("GPL");
178 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
179 MODULE_DESCRIPTION("Simulated MTD driver for testing");
180