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 check_offs_len(struct mtd_info *mtd, loff_t ofs, uint64_t len)
36{
37	int ret = 0;
38
39	/* Start address must align on block boundary */
40	if (mtd_mod_by_eb(ofs, mtd)) {
41		pr_debug("%s: unaligned address\n", __func__);
42		ret = -EINVAL;
43	}
44
45	/* Length must align on block boundary */
46	if (mtd_mod_by_eb(len, mtd)) {
47		pr_debug("%s: length not block aligned\n", __func__);
48		ret = -EINVAL;
49	}
50
51	return ret;
52}
53
54static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
55{
56	if (check_offs_len(mtd, instr->addr, instr->len))
57		return -EINVAL;
58	memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
59	instr->state = MTD_ERASE_DONE;
60	mtd_erase_callback(instr);
61	return 0;
62}
63
64static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
65		size_t *retlen, void **virt, resource_size_t *phys)
66{
67	*virt = mtd->priv + from;
68	*retlen = len;
69	return 0;
70}
71
72static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
73{
74	return 0;
75}
76
77/*
78 * Allow NOMMU mmap() to directly map the device (if not NULL)
79 * - return the address to which the offset maps
80 * - return -ENOSYS to indicate refusal to do the mapping
81 */
82static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
83					   unsigned long len,
84					   unsigned long offset,
85					   unsigned long flags)
86{
87	return (unsigned long) mtd->priv + offset;
88}
89
90static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
91		size_t *retlen, u_char *buf)
92{
93	memcpy(buf, mtd->priv + from, len);
94	*retlen = len;
95	return 0;
96}
97
98static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
99		size_t *retlen, const u_char *buf)
100{
101	memcpy((char *)mtd->priv + to, buf, len);
102	*retlen = len;
103	return 0;
104}
105
106static void __exit cleanup_mtdram(void)
107{
108	if (mtd_info) {
109		mtd_device_unregister(mtd_info);
110		vfree(mtd_info->priv);
111		kfree(mtd_info);
112	}
113}
114
115int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
116		unsigned long size, const char *name)
117{
118	memset(mtd, 0, sizeof(*mtd));
119
120	/* Setup the MTD structure */
121	mtd->name = name;
122	mtd->type = MTD_RAM;
123	mtd->flags = MTD_CAP_RAM;
124	mtd->size = size;
125	mtd->writesize = 1;
126	mtd->writebufsize = 64; /* Mimic CFI NOR flashes */
127	mtd->erasesize = MTDRAM_ERASE_SIZE;
128	mtd->priv = mapped_address;
129
130	mtd->owner = THIS_MODULE;
131	mtd->_erase = ram_erase;
132	mtd->_point = ram_point;
133	mtd->_unpoint = ram_unpoint;
134	mtd->_get_unmapped_area = ram_get_unmapped_area;
135	mtd->_read = ram_read;
136	mtd->_write = ram_write;
137
138	if (mtd_device_register(mtd, NULL, 0))
139		return -EIO;
140
141	return 0;
142}
143
144static int __init init_mtdram(void)
145{
146	void *addr;
147	int err;
148
149	if (!total_size)
150		return -EINVAL;
151
152	/* Allocate some memory */
153	mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
154	if (!mtd_info)
155		return -ENOMEM;
156
157	addr = vmalloc(MTDRAM_TOTAL_SIZE);
158	if (!addr) {
159		kfree(mtd_info);
160		mtd_info = NULL;
161		return -ENOMEM;
162	}
163	err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
164	if (err) {
165		vfree(addr);
166		kfree(mtd_info);
167		mtd_info = NULL;
168		return err;
169	}
170	memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
171	return err;
172}
173
174module_init(init_mtdram);
175module_exit(cleanup_mtdram);
176
177MODULE_LICENSE("GPL");
178MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
179MODULE_DESCRIPTION("Simulated MTD driver for testing");
180