Linux Kernel  3.7.1
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mtdram.c
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1 /*
2  * mtdram - a test mtd device
3  * Author: Alexander Larsson <[email protected]>
4  *
5  * Copyright (c) 1999 Alexander Larsson <[email protected]>
6  * Copyright (c) 2005 Joern Engel <[email protected]>
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
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 
35 static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
36 {
37  memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
38  instr->state = MTD_ERASE_DONE;
39  mtd_erase_callback(instr);
40  return 0;
41 }
42 
43 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
44  size_t *retlen, void **virt, resource_size_t *phys)
45 {
46  *virt = mtd->priv + from;
47  *retlen = len;
48  return 0;
49 }
50 
51 static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
52 {
53  return 0;
54 }
55 
56 /*
57  * Allow NOMMU mmap() to directly map the device (if not NULL)
58  * - return the address to which the offset maps
59  * - return -ENOSYS to indicate refusal to do the mapping
60  */
61 static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
62  unsigned long len,
63  unsigned long offset,
64  unsigned long flags)
65 {
66  return (unsigned long) mtd->priv + offset;
67 }
68 
69 static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
70  size_t *retlen, u_char *buf)
71 {
72  memcpy(buf, mtd->priv + from, len);
73  *retlen = len;
74  return 0;
75 }
76 
77 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
78  size_t *retlen, const u_char *buf)
79 {
80  memcpy((char *)mtd->priv + to, buf, len);
81  *retlen = len;
82  return 0;
83 }
84 
85 static void __exit cleanup_mtdram(void)
86 {
87  if (mtd_info) {
88  mtd_device_unregister(mtd_info);
89  vfree(mtd_info->priv);
90  kfree(mtd_info);
91  }
92 }
93 
94 int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
95  unsigned long size, char *name)
96 {
97  memset(mtd, 0, sizeof(*mtd));
98 
99  /* Setup the MTD structure */
100  mtd->name = name;
101  mtd->type = MTD_RAM;
102  mtd->flags = MTD_CAP_RAM;
103  mtd->size = size;
104  mtd->writesize = 1;
105  mtd->writebufsize = 64; /* Mimic CFI NOR flashes */
107  mtd->priv = mapped_address;
108 
109  mtd->owner = THIS_MODULE;
110  mtd->_erase = ram_erase;
111  mtd->_point = ram_point;
112  mtd->_unpoint = ram_unpoint;
113  mtd->_get_unmapped_area = ram_get_unmapped_area;
114  mtd->_read = ram_read;
115  mtd->_write = ram_write;
116 
117  if (mtd_device_register(mtd, NULL, 0))
118  return -EIO;
119 
120  return 0;
121 }
122 
123 static int __init init_mtdram(void)
124 {
125  void *addr;
126  int err;
127 
128  if (!total_size)
129  return -EINVAL;
130 
131  /* Allocate some memory */
132  mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
133  if (!mtd_info)
134  return -ENOMEM;
135 
136  addr = vmalloc(MTDRAM_TOTAL_SIZE);
137  if (!addr) {
138  kfree(mtd_info);
139  mtd_info = NULL;
140  return -ENOMEM;
141  }
142  err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
143  if (err) {
144  vfree(addr);
145  kfree(mtd_info);
146  mtd_info = NULL;
147  return err;
148  }
149  memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
150  return err;
151 }
152 
153 module_init(init_mtdram);
154 module_exit(cleanup_mtdram);
155 
156 MODULE_LICENSE("GPL");
157 MODULE_AUTHOR("Alexander Larsson <[email protected]>");
158 MODULE_DESCRIPTION("Simulated MTD driver for testing");