mtdram.c revision 07be303d22ac7e067b8a7172a4043ebe32b74b33 
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
20static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE;
21static 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
26module_param(total_size, ulong, 0);
27MODULE_PARM_DESC(total_size, "Total device size in KiB");
28module_param(erase_size, ulong, 0);
29MODULE_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..
33static struct mtd_info *mtd_info;
34
35static 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
48static 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
63static 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 */
72static 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
80static 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
92static 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
104static 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
113int 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
143static 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
173module_init(init_mtdram);
174module_exit(cleanup_mtdram);
175
176MODULE_LICENSE("GPL");
177MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
178MODULE_DESCRIPTION("Simulated MTD driver for testing");
179