xref: /openbmc/linux/drivers/mtd/devices/mtdram.c (revision 22246614)
1 /*
2  * mtdram - a test mtd device
3  * $Id: mtdram.c,v 1.37 2005/04/21 03:42:11 joern Exp $
4  * Author: Alexander Larsson <alex@cendio.se>
5  *
6  * Copyright (c) 1999 Alexander Larsson <alex@cendio.se>
7  * Copyright (c) 2005 Joern Engel <joern@wh.fh-wedel.de>
8  *
9  * This code is GPL
10  *
11  */
12 
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/ioport.h>
16 #include <linux/vmalloc.h>
17 #include <linux/init.h>
18 #include <linux/mtd/compatmac.h>
19 #include <linux/mtd/mtd.h>
20 #include <linux/mtd/mtdram.h>
21 
22 static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE;
23 static unsigned long erase_size = CONFIG_MTDRAM_ERASE_SIZE;
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 #endif
33 
34 // We could store these in the mtd structure, but we only support 1 device..
35 static struct mtd_info *mtd_info;
36 
37 static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
38 {
39 	if (instr->addr + instr->len > mtd->size)
40 		return -EINVAL;
41 
42 	memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
43 
44 	instr->state = MTD_ERASE_DONE;
45 	mtd_erase_callback(instr);
46 
47 	return 0;
48 }
49 
50 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
51 		size_t *retlen, void **virt, resource_size_t *phys)
52 {
53 	if (from + len > mtd->size)
54 		return -EINVAL;
55 
56 	/* can we return a physical address with this driver? */
57 	if (phys)
58 		return -EINVAL;
59 
60 	*virt = mtd->priv + from;
61 	*retlen = len;
62 	return 0;
63 }
64 
65 static void ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
66 {
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 	if (from + len > mtd->size)
73 		return -EINVAL;
74 
75 	memcpy(buf, mtd->priv + from, len);
76 
77 	*retlen = len;
78 	return 0;
79 }
80 
81 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
82 		size_t *retlen, const u_char *buf)
83 {
84 	if (to + len > mtd->size)
85 		return -EINVAL;
86 
87 	memcpy((char *)mtd->priv + to, buf, len);
88 
89 	*retlen = len;
90 	return 0;
91 }
92 
93 static void __exit cleanup_mtdram(void)
94 {
95 	if (mtd_info) {
96 		del_mtd_device(mtd_info);
97 		vfree(mtd_info->priv);
98 		kfree(mtd_info);
99 	}
100 }
101 
102 int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
103 		unsigned long size, char *name)
104 {
105 	memset(mtd, 0, sizeof(*mtd));
106 
107 	/* Setup the MTD structure */
108 	mtd->name = name;
109 	mtd->type = MTD_RAM;
110 	mtd->flags = MTD_CAP_RAM;
111 	mtd->size = size;
112 	mtd->writesize = 1;
113 	mtd->erasesize = MTDRAM_ERASE_SIZE;
114 	mtd->priv = mapped_address;
115 
116 	mtd->owner = THIS_MODULE;
117 	mtd->erase = ram_erase;
118 	mtd->point = ram_point;
119 	mtd->unpoint = ram_unpoint;
120 	mtd->read = ram_read;
121 	mtd->write = ram_write;
122 
123 	if (add_mtd_device(mtd)) {
124 		return -EIO;
125 	}
126 
127 	return 0;
128 }
129 
130 static int __init init_mtdram(void)
131 {
132 	void *addr;
133 	int err;
134 
135 	if (!total_size)
136 		return -EINVAL;
137 
138 	/* Allocate some memory */
139 	mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
140 	if (!mtd_info)
141 		return -ENOMEM;
142 
143 	addr = vmalloc(MTDRAM_TOTAL_SIZE);
144 	if (!addr) {
145 		kfree(mtd_info);
146 		mtd_info = NULL;
147 		return -ENOMEM;
148 	}
149 	err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
150 	if (err) {
151 		vfree(addr);
152 		kfree(mtd_info);
153 		mtd_info = NULL;
154 		return err;
155 	}
156 	memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
157 	return err;
158 }
159 
160 module_init(init_mtdram);
161 module_exit(cleanup_mtdram);
162 
163 MODULE_LICENSE("GPL");
164 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
165 MODULE_DESCRIPTION("Simulated MTD driver for testing");
166