1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* drivers/mtd/maps/plat-ram.c
3 *
4 * (c) 2004-2005 Simtec Electronics
5 * http://www.simtec.co.uk/products/SWLINUX/
6 * Ben Dooks <ben@simtec.co.uk>
7 *
8 * Generic platform device based RAM map
9 */
10
11 #include <linux/module.h>
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/string.h>
15 #include <linux/ioport.h>
16 #include <linux/device.h>
17 #include <linux/slab.h>
18 #include <linux/platform_device.h>
19
20 #include <linux/mtd/mtd.h>
21 #include <linux/mtd/map.h>
22 #include <linux/mtd/partitions.h>
23 #include <linux/mtd/plat-ram.h>
24
25 #include <asm/io.h>
26
27 /* private structure for each mtd platform ram device created */
28
29 struct platram_info {
30 struct device *dev;
31 struct mtd_info *mtd;
32 struct map_info map;
33 struct platdata_mtd_ram *pdata;
34 };
35
36 /* to_platram_info()
37 *
38 * device private data to struct platram_info conversion
39 */
40
to_platram_info(struct platform_device * dev)41 static inline struct platram_info *to_platram_info(struct platform_device *dev)
42 {
43 return platform_get_drvdata(dev);
44 }
45
46 /* platram_setrw
47 *
48 * call the platform device's set rw/ro control
49 *
50 * to = 0 => read-only
51 * = 1 => read-write
52 */
53
platram_setrw(struct platram_info * info,int to)54 static inline void platram_setrw(struct platram_info *info, int to)
55 {
56 if (info->pdata == NULL)
57 return;
58
59 if (info->pdata->set_rw != NULL)
60 (info->pdata->set_rw)(info->dev, to);
61 }
62
63 /* platram_remove
64 *
65 * called to remove the device from the driver's control
66 */
67
platram_remove(struct platform_device * pdev)68 static int platram_remove(struct platform_device *pdev)
69 {
70 struct platram_info *info = to_platram_info(pdev);
71
72 dev_dbg(&pdev->dev, "removing device\n");
73
74 if (info == NULL)
75 return 0;
76
77 if (info->mtd) {
78 mtd_device_unregister(info->mtd);
79 map_destroy(info->mtd);
80 }
81
82 /* ensure ram is left read-only */
83
84 platram_setrw(info, PLATRAM_RO);
85
86 kfree(info);
87
88 return 0;
89 }
90
91 /* platram_probe
92 *
93 * called from device drive system when a device matching our
94 * driver is found.
95 */
96
platram_probe(struct platform_device * pdev)97 static int platram_probe(struct platform_device *pdev)
98 {
99 struct platdata_mtd_ram *pdata;
100 struct platram_info *info;
101 struct resource *res;
102 int err = 0;
103
104 dev_dbg(&pdev->dev, "probe entered\n");
105
106 if (dev_get_platdata(&pdev->dev) == NULL) {
107 dev_err(&pdev->dev, "no platform data supplied\n");
108 err = -ENOENT;
109 goto exit_error;
110 }
111
112 pdata = dev_get_platdata(&pdev->dev);
113
114 info = kzalloc(sizeof(*info), GFP_KERNEL);
115 if (info == NULL) {
116 err = -ENOMEM;
117 goto exit_error;
118 }
119
120 platform_set_drvdata(pdev, info);
121
122 info->dev = &pdev->dev;
123 info->pdata = pdata;
124
125 /* get the resource for the memory mapping */
126 info->map.virt = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
127 if (IS_ERR(info->map.virt)) {
128 err = PTR_ERR(info->map.virt);
129 goto exit_free;
130 }
131
132 dev_dbg(&pdev->dev, "got platform resource %p (0x%llx)\n", res,
133 (unsigned long long)res->start);
134
135 /* setup map parameters */
136
137 info->map.phys = res->start;
138 info->map.size = resource_size(res);
139 info->map.name = pdata->mapname != NULL ?
140 (char *)pdata->mapname : (char *)pdev->name;
141 info->map.bankwidth = pdata->bankwidth;
142
143 dev_dbg(&pdev->dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size);
144
145 simple_map_init(&info->map);
146
147 dev_dbg(&pdev->dev, "initialised map, probing for mtd\n");
148
149 /* probe for the right mtd map driver
150 * supplied by the platform_data struct */
151
152 if (pdata->map_probes) {
153 const char * const *map_probes = pdata->map_probes;
154
155 for ( ; !info->mtd && *map_probes; map_probes++)
156 info->mtd = do_map_probe(*map_probes , &info->map);
157 }
158 /* fallback to map_ram */
159 else
160 info->mtd = do_map_probe("map_ram", &info->map);
161
162 if (info->mtd == NULL) {
163 dev_err(&pdev->dev, "failed to probe for map_ram\n");
164 err = -ENOMEM;
165 goto exit_free;
166 }
167
168 info->mtd->dev.parent = &pdev->dev;
169
170 platram_setrw(info, PLATRAM_RW);
171
172 /* check to see if there are any available partitions, or whether
173 * to add this device whole */
174
175 err = mtd_device_parse_register(info->mtd, pdata->probes, NULL,
176 pdata->partitions,
177 pdata->nr_partitions);
178 if (err) {
179 dev_err(&pdev->dev, "failed to register mtd device\n");
180 goto exit_free;
181 }
182
183 dev_info(&pdev->dev, "registered mtd device\n");
184
185 if (pdata->nr_partitions) {
186 /* add the whole device. */
187 err = mtd_device_register(info->mtd, NULL, 0);
188 if (err) {
189 dev_err(&pdev->dev,
190 "failed to register the entire device\n");
191 goto exit_free;
192 }
193 }
194
195 return 0;
196
197 exit_free:
198 platram_remove(pdev);
199 exit_error:
200 return err;
201 }
202
203 /* device driver info */
204
205 /* work with hotplug and coldplug */
206 MODULE_ALIAS("platform:mtd-ram");
207
208 static struct platform_driver platram_driver = {
209 .probe = platram_probe,
210 .remove = platram_remove,
211 .driver = {
212 .name = "mtd-ram",
213 },
214 };
215
216 module_platform_driver(platram_driver);
217
218 MODULE_LICENSE("GPL");
219 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
220 MODULE_DESCRIPTION("MTD platform RAM map driver");
221