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	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
43static 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
51static 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 */
61static 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
69static 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
77static 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
85static 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
94int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
95		unsigned long size, const 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 */
106	mtd->erasesize = MTDRAM_ERASE_SIZE;
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
123static 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
153module_init(init_mtdram);
154module_exit(cleanup_mtdram);
155
156MODULE_LICENSE("GPL");
157MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
158MODULE_DESCRIPTION("Simulated MTD driver for testing");
159