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/mm.h>
17#include <linux/init.h>
18#include <linux/mtd/mtd.h>
19#include <linux/mtd/mtdram.h>
20
21static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE;
22static unsigned long erase_size = CONFIG_MTDRAM_ERASE_SIZE;
23static unsigned long writebuf_size = 64;
24#define MTDRAM_TOTAL_SIZE (total_size * 1024)
25#define MTDRAM_ERASE_SIZE (erase_size * 1024)
26
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
34// We could store these in the mtd structure, but we only support 1 device..
35static struct mtd_info *mtd_info;
36
37static int check_offs_len(struct mtd_info *mtd, loff_t ofs, uint64_t len)
38{
39 int ret = 0;
40
41 /* Start address must align on block boundary */
42 if (mtd_mod_by_eb(sz: ofs, mtd)) {
43 pr_debug("%s: unaligned address\n", __func__);
44 ret = -EINVAL;
45 }
46
47 /* Length must align on block boundary */
48 if (mtd_mod_by_eb(sz: len, mtd)) {
49 pr_debug("%s: length not block aligned\n", __func__);
50 ret = -EINVAL;
51 }
52
53 return ret;
54}
55
56static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
57{
58 if (check_offs_len(mtd, ofs: instr->addr, len: instr->len))
59 return -EINVAL;
60 memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
61
62 return 0;
63}
64
65static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
66 size_t *retlen, void **virt, resource_size_t *phys)
67{
68 *virt = mtd->priv + from;
69 *retlen = len;
70
71 if (phys) {
72 /* limit retlen to the number of contiguous physical pages */
73 unsigned long page_ofs = offset_in_page(*virt);
74 void *addr = *virt - page_ofs;
75 unsigned long pfn1, pfn0 = vmalloc_to_pfn(addr);
76
77 *phys = __pfn_to_phys(pfn0) + page_ofs;
78 len += page_ofs;
79 while (len > PAGE_SIZE) {
80 len -= PAGE_SIZE;
81 addr += PAGE_SIZE;
82 pfn0++;
83 pfn1 = vmalloc_to_pfn(addr);
84 if (pfn1 != pfn0) {
85 *retlen = addr - *virt;
86 break;
87 }
88 }
89 }
90
91 return 0;
92}
93
94static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
95{
96 return 0;
97}
98
99static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
100 size_t *retlen, u_char *buf)
101{
102 memcpy(buf, mtd->priv + from, len);
103 *retlen = len;
104 return 0;
105}
106
107static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
108 size_t *retlen, const u_char *buf)
109{
110 memcpy((char *)mtd->priv + to, buf, len);
111 *retlen = len;
112 return 0;
113}
114
115static void __exit cleanup_mtdram(void)
116{
117 if (mtd_info) {
118 mtd_device_unregister(master: mtd_info);
119 vfree(addr: mtd_info->priv);
120 kfree(objp: mtd_info);
121 }
122}
123
124int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
125 unsigned long size, const char *name)
126{
127 memset(mtd, 0, sizeof(*mtd));
128
129 /* Setup the MTD structure */
130 mtd->name = name;
131 mtd->type = MTD_RAM;
132 mtd->flags = MTD_CAP_RAM;
133 mtd->size = size;
134 mtd->writesize = 1;
135 mtd->writebufsize = writebuf_size;
136 mtd->erasesize = MTDRAM_ERASE_SIZE;
137 mtd->priv = mapped_address;
138
139 mtd->owner = THIS_MODULE;
140 mtd->_erase = ram_erase;
141 mtd->_point = ram_point;
142 mtd->_unpoint = ram_unpoint;
143 mtd->_read = ram_read;
144 mtd->_write = ram_write;
145
146 if (mtd_device_register(mtd, NULL, 0))
147 return -EIO;
148
149 return 0;
150}
151
152static int __init init_mtdram(void)
153{
154 void *addr;
155 int err;
156
157 if (!total_size)
158 return -EINVAL;
159
160 /* Allocate some memory */
161 mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
162 if (!mtd_info)
163 return -ENOMEM;
164
165 addr = vmalloc(MTDRAM_TOTAL_SIZE);
166 if (!addr) {
167 kfree(objp: mtd_info);
168 mtd_info = NULL;
169 return -ENOMEM;
170 }
171 err = mtdram_init_device(mtd: mtd_info, mapped_address: addr, MTDRAM_TOTAL_SIZE, name: "mtdram test device");
172 if (err) {
173 vfree(addr);
174 kfree(objp: mtd_info);
175 mtd_info = NULL;
176 return err;
177 }
178 memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
179 return err;
180}
181
182module_init(init_mtdram);
183module_exit(cleanup_mtdram);
184
185MODULE_LICENSE("GPL");
186MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
187MODULE_DESCRIPTION("Simulated MTD driver for testing");
188

source code of linux/drivers/mtd/devices/mtdram.c