Linux Kernel  3.7.1
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uclinux.c
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1 /****************************************************************************/
2 
3 /*
4  * uclinux.c -- generic memory mapped MTD driver for uclinux
5  *
6  * (C) Copyright 2002, Greg Ungerer ([email protected])
7  */
8 
9 /****************************************************************************/
10 
11 #include <linux/module.h>
12 #include <linux/types.h>
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/fs.h>
16 #include <linux/mm.h>
17 #include <linux/major.h>
18 #include <linux/mtd/mtd.h>
19 #include <linux/mtd/map.h>
20 #include <linux/mtd/partitions.h>
21 #include <asm/io.h>
22 #include <asm/sections.h>
23 
24 /****************************************************************************/
25 
26 struct map_info uclinux_ram_map = {
27  .name = "RAM",
28  .phys = (unsigned long)__bss_stop,
29  .size = 0,
30 };
31 
32 static struct mtd_info *uclinux_ram_mtdinfo;
33 
34 /****************************************************************************/
35 
36 static struct mtd_partition uclinux_romfs[] = {
37  { .name = "ROMfs" }
38 };
39 
40 #define NUM_PARTITIONS ARRAY_SIZE(uclinux_romfs)
41 
42 /****************************************************************************/
43 
44 static int uclinux_point(struct mtd_info *mtd, loff_t from, size_t len,
45  size_t *retlen, void **virt, resource_size_t *phys)
46 {
47  struct map_info *map = mtd->priv;
48  *virt = map->virt + from;
49  if (phys)
50  *phys = map->phys + from;
51  *retlen = len;
52  return(0);
53 }
54 
55 /****************************************************************************/
56 
57 static int __init uclinux_mtd_init(void)
58 {
59  struct mtd_info *mtd;
60  struct map_info *mapp;
61 
62  mapp = &uclinux_ram_map;
63  if (!mapp->size)
64  mapp->size = PAGE_ALIGN(ntohl(*((unsigned long *)(mapp->phys + 8))));
65  mapp->bankwidth = 4;
66 
67  printk("uclinux[mtd]: RAM probe address=0x%x size=0x%x\n",
68  (int) mapp->phys, (int) mapp->size);
69 
70  /*
71  * The filesystem is guaranteed to be in direct mapped memory. It is
72  * directly following the kernels own bss region. Following the same
73  * mechanism used by architectures setting up traditional initrds we
74  * use phys_to_virt to get the virtual address of its start.
75  */
76  mapp->virt = phys_to_virt(mapp->phys);
77 
78  if (mapp->virt == 0) {
79  printk("uclinux[mtd]: no virtual mapping?\n");
80  return(-EIO);
81  }
82 
83  simple_map_init(mapp);
84 
85  mtd = do_map_probe("map_ram", mapp);
86  if (!mtd) {
87  printk("uclinux[mtd]: failed to find a mapping?\n");
88  return(-ENXIO);
89  }
90 
91  mtd->owner = THIS_MODULE;
92  mtd->_point = uclinux_point;
93  mtd->priv = mapp;
94 
95  uclinux_ram_mtdinfo = mtd;
96  mtd_device_register(mtd, uclinux_romfs, NUM_PARTITIONS);
97 
98  return(0);
99 }
100 
101 /****************************************************************************/
102 
103 static void __exit uclinux_mtd_cleanup(void)
104 {
105  if (uclinux_ram_mtdinfo) {
106  mtd_device_unregister(uclinux_ram_mtdinfo);
107  map_destroy(uclinux_ram_mtdinfo);
108  uclinux_ram_mtdinfo = NULL;
109  }
110  if (uclinux_ram_map.virt)
111  uclinux_ram_map.virt = 0;
112 }
113 
114 /****************************************************************************/
115 
116 module_init(uclinux_mtd_init);
117 module_exit(uclinux_mtd_cleanup);
118 
119 MODULE_LICENSE("GPL");
120 MODULE_AUTHOR("Greg Ungerer <[email protected]>");
121 MODULE_DESCRIPTION("Generic RAM based MTD for uClinux");
122 
123 /****************************************************************************/
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