xref: /openbmc/linux/drivers/mtd/maps/plat-ram.c (revision 0e0d59f2)
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