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
ram_erase(struct mtd_info * mtd,struct erase_info * instr)35 static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
36 {
37 if (instr->addr + instr->len > mtd->size)
38 return -EINVAL;
39
40 memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
41
42 instr->state = MTD_ERASE_DONE;
43 mtd_erase_callback(instr);
44
45 return 0;
46 }
47
ram_point(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,void ** virt,resource_size_t * phys)48 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
49 size_t *retlen, void **virt, resource_size_t *phys)
50 {
51 if (from + len > mtd->size)
52 return -EINVAL;
53
54 /* can we return a physical address with this driver? */
55 if (phys)
56 return -EINVAL;
57
58 *virt = mtd->priv + from;
59 *retlen = len;
60 return 0;
61 }
62
ram_unpoint(struct mtd_info * mtd,loff_t from,size_t len)63 static void ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
64 {
65 }
66
67 /*
68 * Allow NOMMU mmap() to directly map the device (if not NULL)
69 * - return the address to which the offset maps
70 * - return -ENOSYS to indicate refusal to do the mapping
71 */
ram_get_unmapped_area(struct mtd_info * mtd,unsigned long len,unsigned long offset,unsigned long flags)72 static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
73 unsigned long len,
74 unsigned long offset,
75 unsigned long flags)
76 {
77 return (unsigned long) mtd->priv + offset;
78 }
79
ram_read(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,u_char * buf)80 static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
81 size_t *retlen, u_char *buf)
82 {
83 if (from + len > mtd->size)
84 return -EINVAL;
85
86 memcpy(buf, mtd->priv + from, len);
87
88 *retlen = len;
89 return 0;
90 }
91
ram_write(struct mtd_info * mtd,loff_t to,size_t len,size_t * retlen,const u_char * buf)92 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
93 size_t *retlen, const u_char *buf)
94 {
95 if (to + len > mtd->size)
96 return -EINVAL;
97
98 memcpy((char *)mtd->priv + to, buf, len);
99
100 *retlen = len;
101 return 0;
102 }
103
cleanup_mtdram(void)104 static void __exit cleanup_mtdram(void)
105 {
106 if (mtd_info) {
107 del_mtd_device(mtd_info);
108 vfree(mtd_info->priv);
109 kfree(mtd_info);
110 }
111 }
112
mtdram_init_device(struct mtd_info * mtd,void * mapped_address,unsigned long size,char * name)113 int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
114 unsigned long size, char *name)
115 {
116 memset(mtd, 0, sizeof(*mtd));
117
118 /* Setup the MTD structure */
119 mtd->name = name;
120 mtd->type = MTD_RAM;
121 mtd->flags = MTD_CAP_RAM;
122 mtd->size = size;
123 mtd->writesize = 1;
124 mtd->writebufsize = 64; /* Mimic CFI NOR flashes */
125 mtd->erasesize = MTDRAM_ERASE_SIZE;
126 mtd->priv = mapped_address;
127
128 mtd->owner = THIS_MODULE;
129 mtd->erase = ram_erase;
130 mtd->point = ram_point;
131 mtd->unpoint = ram_unpoint;
132 mtd->get_unmapped_area = ram_get_unmapped_area;
133 mtd->read = ram_read;
134 mtd->write = ram_write;
135
136 if (add_mtd_device(mtd)) {
137 return -EIO;
138 }
139
140 return 0;
141 }
142
init_mtdram(void)143 static int __init init_mtdram(void)
144 {
145 void *addr;
146 int err;
147
148 if (!total_size)
149 return -EINVAL;
150
151 /* Allocate some memory */
152 mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
153 if (!mtd_info)
154 return -ENOMEM;
155
156 addr = vmalloc(MTDRAM_TOTAL_SIZE);
157 if (!addr) {
158 kfree(mtd_info);
159 mtd_info = NULL;
160 return -ENOMEM;
161 }
162 err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
163 if (err) {
164 vfree(addr);
165 kfree(mtd_info);
166 mtd_info = NULL;
167 return err;
168 }
169 memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
170 return err;
171 }
172
173 module_init(init_mtdram);
174 module_exit(cleanup_mtdram);
175
176 MODULE_LICENSE("GPL");
177 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
178 MODULE_DESCRIPTION("Simulated MTD driver for testing");
179