blob: 6eb52ed50c6a8eef289327e63c84e8238f2562c9 [file] [log] [blame]
Kyungmin Parke29c22f2008-11-19 16:20:36 +01001/*
2 * Core registration and callback routines for MTD
3 * drivers and users.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9
10#include <linux/mtd/mtd.h>
11#include <linux/mtd/compat.h>
12#include <ubi_uboot.h>
13
14struct mtd_info *mtd_table[MAX_MTD_DEVICES];
15
16int add_mtd_device(struct mtd_info *mtd)
17{
18 int i;
19
20 BUG_ON(mtd->writesize == 0);
21
22 for (i = 0; i < MAX_MTD_DEVICES; i++)
23 if (!mtd_table[i]) {
24 mtd_table[i] = mtd;
25 mtd->index = i;
26 mtd->usecount = 0;
27
Kyungmin Parke29c22f2008-11-19 16:20:36 +010028 /* No need to get a refcount on the module containing
29 the notifier, since we hold the mtd_table_mutex */
30
31 /* We _know_ we aren't being removed, because
32 our caller is still holding us here. So none
33 of this try_ nonsense, and no bitching about it
34 either. :) */
35 return 0;
36 }
37
38 return 1;
39}
40
41/**
42 * del_mtd_device - unregister an MTD device
43 * @mtd: pointer to MTD device info structure
44 *
45 * Remove a device from the list of MTD devices present in the system,
46 * and notify each currently active MTD 'user' of its departure.
47 * Returns zero on success or 1 on failure, which currently will happen
48 * if the requested device does not appear to be present in the list.
49 */
50int del_mtd_device(struct mtd_info *mtd)
51{
52 int ret;
53
54 if (mtd_table[mtd->index] != mtd) {
55 ret = -ENODEV;
56 } else if (mtd->usecount) {
57 printk(KERN_NOTICE "Removing MTD device #%d (%s)"
58 " with use count %d\n",
59 mtd->index, mtd->name, mtd->usecount);
60 ret = -EBUSY;
61 } else {
62 /* No need to get a refcount on the module containing
63 * the notifier, since we hold the mtd_table_mutex */
64 mtd_table[mtd->index] = NULL;
65
66 ret = 0;
67 }
68
69 return ret;
70}
71
72/**
73 * get_mtd_device - obtain a validated handle for an MTD device
74 * @mtd: last known address of the required MTD device
75 * @num: internal device number of the required MTD device
76 *
77 * Given a number and NULL address, return the num'th entry in the device
78 * table, if any. Given an address and num == -1, search the device table
79 * for a device with that address and return if it's still present. Given
80 * both, return the num'th driver only if its address matches. Return
81 * error code if not.
82 */
83struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
84{
85 struct mtd_info *ret = NULL;
86 int i, err = -ENODEV;
87
88 if (num == -1) {
89 for (i = 0; i < MAX_MTD_DEVICES; i++)
90 if (mtd_table[i] == mtd)
91 ret = mtd_table[i];
92 } else if (num < MAX_MTD_DEVICES) {
93 ret = mtd_table[num];
94 if (mtd && mtd != ret)
95 ret = NULL;
96 }
97
98 if (!ret)
99 goto out_unlock;
100
101 ret->usecount++;
102 return ret;
103
104out_unlock:
105 return ERR_PTR(err);
106}
107
108/**
109 * get_mtd_device_nm - obtain a validated handle for an MTD device by
110 * device name
111 * @name: MTD device name to open
112 *
113 * This function returns MTD device description structure in case of
114 * success and an error code in case of failure.
115 */
116struct mtd_info *get_mtd_device_nm(const char *name)
117{
118 int i, err = -ENODEV;
119 struct mtd_info *mtd = NULL;
120
121 for (i = 0; i < MAX_MTD_DEVICES; i++) {
122 if (mtd_table[i] && !strcmp(name, mtd_table[i]->name)) {
123 mtd = mtd_table[i];
124 break;
125 }
126 }
127
128 if (!mtd)
129 goto out_unlock;
130
131 mtd->usecount++;
132 return mtd;
133
134out_unlock:
135 return ERR_PTR(err);
136}
137
138void put_mtd_device(struct mtd_info *mtd)
139{
140 int c;
141
142 c = --mtd->usecount;
143 BUG_ON(c < 0);
144}