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
21 static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE;
22 static unsigned long erase_size = CONFIG_MTDRAM_ERASE_SIZE;
23 static unsigned long writebuf_size = 64;
24 #define MTDRAM_TOTAL_SIZE (total_size * 1024)
25 #define MTDRAM_ERASE_SIZE (erase_size * 1024)
26
27 #ifdef MODULE
28 module_param(total_size, ulong, 0);
29 MODULE_PARM_DESC(total_size, "Total device size in KiB");
30 module_param(erase_size, ulong, 0);
31 MODULE_PARM_DESC(erase_size, "Device erase block size in KiB");
32 module_param(writebuf_size, ulong, 0);
33 MODULE_PARM_DESC(writebuf_size, "Device write buf size in Bytes (Default: 64)");
34 #endif
35
36 // We could store these in the mtd structure, but we only support 1 device..
37 static struct mtd_info *mtd_info;
38
check_offs_len(struct mtd_info * mtd,loff_t ofs,uint64_t len)39 static int check_offs_len(struct mtd_info *mtd, loff_t ofs, uint64_t len)
40 {
41 int ret = 0;
42
43 /* Start address must align on block boundary */
44 if (mtd_mod_by_eb(ofs, mtd)) {
45 pr_debug("%s: unaligned address\n", __func__);
46 ret = -EINVAL;
47 }
48
49 /* Length must align on block boundary */
50 if (mtd_mod_by_eb(len, mtd)) {
51 pr_debug("%s: length not block aligned\n", __func__);
52 ret = -EINVAL;
53 }
54
55 return ret;
56 }
57
ram_erase(struct mtd_info * mtd,struct erase_info * instr)58 static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
59 {
60 if (check_offs_len(mtd, instr->addr, instr->len))
61 return -EINVAL;
62 memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
63
64 return 0;
65 }
66
ram_point(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,void ** virt,resource_size_t * phys)67 static 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
73 if (phys) {
74 /* limit retlen to the number of contiguous physical pages */
75 unsigned long page_ofs = offset_in_page(*virt);
76 void *addr = *virt - page_ofs;
77 unsigned long pfn1, pfn0 = vmalloc_to_pfn(addr);
78
79 *phys = __pfn_to_phys(pfn0) + page_ofs;
80 len += page_ofs;
81 while (len > PAGE_SIZE) {
82 len -= PAGE_SIZE;
83 addr += PAGE_SIZE;
84 pfn0++;
85 pfn1 = vmalloc_to_pfn(addr);
86 if (pfn1 != pfn0) {
87 *retlen = addr - *virt;
88 break;
89 }
90 }
91 }
92
93 return 0;
94 }
95
ram_unpoint(struct mtd_info * mtd,loff_t from,size_t len)96 static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
97 {
98 return 0;
99 }
100
ram_read(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,u_char * buf)101 static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
102 size_t *retlen, u_char *buf)
103 {
104 memcpy(buf, mtd->priv + from, len);
105 *retlen = len;
106 return 0;
107 }
108
ram_write(struct mtd_info * mtd,loff_t to,size_t len,size_t * retlen,const u_char * buf)109 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
110 size_t *retlen, const u_char *buf)
111 {
112 memcpy((char *)mtd->priv + to, buf, len);
113 *retlen = len;
114 return 0;
115 }
116
cleanup_mtdram(void)117 static void __exit cleanup_mtdram(void)
118 {
119 if (mtd_info) {
120 mtd_device_unregister(mtd_info);
121 vfree(mtd_info->priv);
122 kfree(mtd_info);
123 }
124 }
125
mtdram_init_device(struct mtd_info * mtd,void * mapped_address,unsigned long size,const char * name)126 int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
127 unsigned long size, const char *name)
128 {
129 memset(mtd, 0, sizeof(*mtd));
130
131 /* Setup the MTD structure */
132 mtd->name = name;
133 mtd->type = MTD_RAM;
134 mtd->flags = MTD_CAP_RAM;
135 mtd->size = size;
136 mtd->writesize = 1;
137 mtd->writebufsize = writebuf_size;
138 mtd->erasesize = MTDRAM_ERASE_SIZE;
139 mtd->priv = mapped_address;
140
141 mtd->owner = THIS_MODULE;
142 mtd->_erase = ram_erase;
143 mtd->_point = ram_point;
144 mtd->_unpoint = ram_unpoint;
145 mtd->_read = ram_read;
146 mtd->_write = ram_write;
147
148 if (mtd_device_register(mtd, NULL, 0))
149 return -EIO;
150
151 return 0;
152 }
153
init_mtdram(void)154 static int __init init_mtdram(void)
155 {
156 void *addr;
157 int err;
158
159 if (!total_size)
160 return -EINVAL;
161
162 /* Allocate some memory */
163 mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
164 if (!mtd_info)
165 return -ENOMEM;
166
167 addr = vmalloc(MTDRAM_TOTAL_SIZE);
168 if (!addr) {
169 kfree(mtd_info);
170 mtd_info = NULL;
171 return -ENOMEM;
172 }
173 err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
174 if (err) {
175 vfree(addr);
176 kfree(mtd_info);
177 mtd_info = NULL;
178 return err;
179 }
180 memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
181 return err;
182 }
183
184 module_init(init_mtdram);
185 module_exit(cleanup_mtdram);
186
187 MODULE_LICENSE("GPL");
188 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
189 MODULE_DESCRIPTION("Simulated MTD driver for testing");
190