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 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
127 	info->map.virt = devm_ioremap_resource(&pdev->dev, res);
128 	if (IS_ERR(info->map.virt)) {
129 		err = PTR_ERR(info->map.virt);
130 		goto exit_free;
131 	}
132 
133 	dev_dbg(&pdev->dev, "got platform resource %p (0x%llx)\n", res,
134 		(unsigned long long)res->start);
135 
136 	/* setup map parameters */
137 
138 	info->map.phys = res->start;
139 	info->map.size = resource_size(res);
140 	info->map.name = pdata->mapname != NULL ?
141 			(char *)pdata->mapname : (char *)pdev->name;
142 	info->map.bankwidth = pdata->bankwidth;
143 
144 	dev_dbg(&pdev->dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size);
145 
146 	simple_map_init(&info->map);
147 
148 	dev_dbg(&pdev->dev, "initialised map, probing for mtd\n");
149 
150 	/* probe for the right mtd map driver
151 	 * supplied by the platform_data struct */
152 
153 	if (pdata->map_probes) {
154 		const char * const *map_probes = pdata->map_probes;
155 
156 		for ( ; !info->mtd && *map_probes; map_probes++)
157 			info->mtd = do_map_probe(*map_probes , &info->map);
158 	}
159 	/* fallback to map_ram */
160 	else
161 		info->mtd = do_map_probe("map_ram", &info->map);
162 
163 	if (info->mtd == NULL) {
164 		dev_err(&pdev->dev, "failed to probe for map_ram\n");
165 		err = -ENOMEM;
166 		goto exit_free;
167 	}
168 
169 	info->mtd->dev.parent = &pdev->dev;
170 
171 	platram_setrw(info, PLATRAM_RW);
172 
173 	/* check to see if there are any available partitions, or whether
174 	 * to add this device whole */
175 
176 	err = mtd_device_parse_register(info->mtd, pdata->probes, NULL,
177 					pdata->partitions,
178 					pdata->nr_partitions);
179 	if (err) {
180 		dev_err(&pdev->dev, "failed to register mtd device\n");
181 		goto exit_free;
182 	}
183 
184 	dev_info(&pdev->dev, "registered mtd device\n");
185 
186 	if (pdata->nr_partitions) {
187 		/* add the whole device. */
188 		err = mtd_device_register(info->mtd, NULL, 0);
189 		if (err) {
190 			dev_err(&pdev->dev,
191 				"failed to register the entire device\n");
192 			goto exit_free;
193 		}
194 	}
195 
196 	return 0;
197 
198  exit_free:
199 	platram_remove(pdev);
200  exit_error:
201 	return err;
202 }
203 
204 /* device driver info */
205 
206 /* work with hotplug and coldplug */
207 MODULE_ALIAS("platform:mtd-ram");
208 
209 static struct platform_driver platram_driver = {
210 	.probe		= platram_probe,
211 	.remove		= platram_remove,
212 	.driver		= {
213 		.name	= "mtd-ram",
214 	},
215 };
216 
217 module_platform_driver(platram_driver);
218 
219 MODULE_LICENSE("GPL");
220 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
221 MODULE_DESCRIPTION("MTD platform RAM map driver");
222