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
29struct 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
41static 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
54static 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
68static void 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;
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
89/* platram_probe
90 *
91 * called from device drive system when a device matching our
92 * driver is found.
93*/
94
95static int platram_probe(struct platform_device *pdev)
96{
97	struct platdata_mtd_ram	*pdata;
98	struct platram_info *info;
99	struct resource *res;
100	int err = 0;
101
102	dev_dbg(&pdev->dev, "probe entered\n");
103
104	if (dev_get_platdata(&pdev->dev) == NULL) {
105		dev_err(&pdev->dev, "no platform data supplied\n");
106		err = -ENOENT;
107		goto exit_error;
108	}
109
110	pdata = dev_get_platdata(&pdev->dev);
111
112	info = kzalloc(sizeof(*info), GFP_KERNEL);
113	if (info == NULL) {
114		err = -ENOMEM;
115		goto exit_error;
116	}
117
118	platform_set_drvdata(pdev, info);
119
120	info->dev = &pdev->dev;
121	info->pdata = pdata;
122
123	/* get the resource for the memory mapping */
124	info->map.virt = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
125	if (IS_ERR(info->map.virt)) {
126		err = PTR_ERR(info->map.virt);
127		goto exit_free;
128	}
129
130	dev_dbg(&pdev->dev, "got platform resource %p (0x%llx)\n", res,
131		(unsigned long long)res->start);
132
133	/* setup map parameters */
134
135	info->map.phys = res->start;
136	info->map.size = resource_size(res);
137	info->map.name = pdata->mapname != NULL ?
138			(char *)pdata->mapname : (char *)pdev->name;
139	info->map.bankwidth = pdata->bankwidth;
140
141	dev_dbg(&pdev->dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size);
142
143	simple_map_init(&info->map);
144
145	dev_dbg(&pdev->dev, "initialised map, probing for mtd\n");
146
147	/* probe for the right mtd map driver
148	 * supplied by the platform_data struct */
149
150	if (pdata->map_probes) {
151		const char * const *map_probes = pdata->map_probes;
152
153		for ( ; !info->mtd && *map_probes; map_probes++)
154			info->mtd = do_map_probe(*map_probes , &info->map);
155	}
156	/* fallback to map_ram */
157	else
158		info->mtd = do_map_probe("map_ram", &info->map);
159
160	if (info->mtd == NULL) {
161		dev_err(&pdev->dev, "failed to probe for map_ram\n");
162		err = -ENOMEM;
163		goto exit_free;
164	}
165
166	info->mtd->dev.parent = &pdev->dev;
167
168	platram_setrw(info, PLATRAM_RW);
169
170	/* check to see if there are any available partitions, or whether
171	 * to add this device whole */
172
173	err = mtd_device_parse_register(info->mtd, pdata->probes, NULL,
174					pdata->partitions,
175					pdata->nr_partitions);
176	if (err) {
177		dev_err(&pdev->dev, "failed to register mtd device\n");
178		goto exit_free;
179	}
180
181	dev_info(&pdev->dev, "registered mtd device\n");
182
183	if (pdata->nr_partitions) {
184		/* add the whole device. */
185		err = mtd_device_register(info->mtd, NULL, 0);
186		if (err) {
187			dev_err(&pdev->dev,
188				"failed to register the entire device\n");
189			goto exit_free;
190		}
191	}
192
193	return 0;
194
195 exit_free:
196	platram_remove(pdev);
197 exit_error:
198	return err;
199}
200
201/* device driver info */
202
203/* work with hotplug and coldplug */
204MODULE_ALIAS("platform:mtd-ram");
205
206static struct platform_driver platram_driver = {
207	.probe		= platram_probe,
208	.remove_new	= platram_remove,
209	.driver		= {
210		.name	= "mtd-ram",
211	},
212};
213
214module_platform_driver(platram_driver);
215
216MODULE_LICENSE("GPL");
217MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
218MODULE_DESCRIPTION("MTD platform RAM map driver");
219