xref: /linux/drivers/mtd/maps/pismo.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
1 /*
2  * PISMO memory driver - http://www.pismoworld.org/
3  *
4  * For ARM Realview and Versatile platforms
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License.
9  */
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/i2c.h>
13 #include <linux/slab.h>
14 #include <linux/platform_device.h>
15 #include <linux/spinlock.h>
16 #include <linux/mutex.h>
17 #include <linux/mtd/physmap.h>
18 #include <linux/mtd/plat-ram.h>
19 #include <linux/mtd/pismo.h>
20 
21 #define PISMO_NUM_CS	5
22 
23 struct pismo_cs_block {
24 	u8	type;
25 	u8	width;
26 	__le16	access;
27 	__le32	size;
28 	u32	reserved[2];
29 	char	device[32];
30 } __packed;
31 
32 struct pismo_eeprom {
33 	struct pismo_cs_block cs[PISMO_NUM_CS];
34 	char	board[15];
35 	u8	sum;
36 } __packed;
37 
38 struct pismo_mem {
39 	phys_addr_t base;
40 	u32	size;
41 	u16	access;
42 	u8	width;
43 	u8	type;
44 };
45 
46 struct pismo_data {
47 	struct i2c_client	*client;
48 	void			(*vpp)(void *, int);
49 	void			*vpp_data;
50 	struct platform_device	*dev[PISMO_NUM_CS];
51 };
52 
53 static void pismo_set_vpp(struct platform_device *pdev, int on)
54 {
55 	struct i2c_client *client = to_i2c_client(pdev->dev.parent);
56 	struct pismo_data *pismo = i2c_get_clientdata(client);
57 
58 	pismo->vpp(pismo->vpp_data, on);
59 }
60 
61 static unsigned int pismo_width_to_bytes(unsigned int width)
62 {
63 	width &= 15;
64 	if (width > 2)
65 		return 0;
66 	return 1 << width;
67 }
68 
69 static int pismo_eeprom_read(struct i2c_client *client, void *buf,
70 	u8 addr, size_t size)
71 {
72 	int ret;
73 	struct i2c_msg msg[] = {
74 		{
75 			.addr = client->addr,
76 			.len = sizeof(addr),
77 			.buf = &addr,
78 		}, {
79 			.addr = client->addr,
80 			.flags = I2C_M_RD,
81 			.len = size,
82 			.buf = buf,
83 		},
84 	};
85 
86 	ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
87 
88 	return ret == ARRAY_SIZE(msg) ? size : -EIO;
89 }
90 
91 static int pismo_add_device(struct pismo_data *pismo, int i,
92 	struct pismo_mem *region, const char *name, void *pdata, size_t psize)
93 {
94 	struct platform_device *dev;
95 	struct resource res = { };
96 	phys_addr_t base = region->base;
97 	int ret;
98 
99 	if (base == ~0)
100 		return -ENXIO;
101 
102 	res.start = base;
103 	res.end = base + region->size - 1;
104 	res.flags = IORESOURCE_MEM;
105 
106 	dev = platform_device_alloc(name, i);
107 	if (!dev)
108 		return -ENOMEM;
109 	dev->dev.parent = &pismo->client->dev;
110 
111 	do {
112 		ret = platform_device_add_resources(dev, &res, 1);
113 		if (ret)
114 			break;
115 
116 		ret = platform_device_add_data(dev, pdata, psize);
117 		if (ret)
118 			break;
119 
120 		ret = platform_device_add(dev);
121 		if (ret)
122 			break;
123 
124 		pismo->dev[i] = dev;
125 		return 0;
126 	} while (0);
127 
128 	platform_device_put(dev);
129 	return ret;
130 }
131 
132 static int pismo_add_nor(struct pismo_data *pismo, int i,
133 	struct pismo_mem *region)
134 {
135 	struct physmap_flash_data data = {
136 		.width = region->width,
137 	};
138 
139 	if (pismo->vpp)
140 		data.set_vpp = pismo_set_vpp;
141 
142 	return pismo_add_device(pismo, i, region, "physmap-flash",
143 		&data, sizeof(data));
144 }
145 
146 static int pismo_add_sram(struct pismo_data *pismo, int i,
147 	struct pismo_mem *region)
148 {
149 	struct platdata_mtd_ram data = {
150 		.bankwidth = region->width,
151 	};
152 
153 	return pismo_add_device(pismo, i, region, "mtd-ram",
154 		&data, sizeof(data));
155 }
156 
157 static void pismo_add_one(struct pismo_data *pismo, int i,
158 	const struct pismo_cs_block *cs, phys_addr_t base)
159 {
160 	struct device *dev = &pismo->client->dev;
161 	struct pismo_mem region;
162 
163 	region.base = base;
164 	region.type = cs->type;
165 	region.width = pismo_width_to_bytes(cs->width);
166 	region.access = le16_to_cpu(cs->access);
167 	region.size = le32_to_cpu(cs->size);
168 
169 	if (region.width == 0) {
170 		dev_err(dev, "cs%u: bad width: %02x, ignoring\n", i, cs->width);
171 		return;
172 	}
173 
174 	/*
175 	 * FIXME: may need to the platforms memory controller here, but at
176 	 * the moment we assume that it has already been correctly setup.
177 	 * The memory controller can also tell us the base address as well.
178 	 */
179 
180 	dev_info(dev, "cs%u: %.32s: type %02x access %u00ps size %uK\n",
181 		i, cs->device, region.type, region.access, region.size / 1024);
182 
183 	switch (region.type) {
184 	case 0:
185 		break;
186 	case 1:
187 		/* static DOC */
188 		break;
189 	case 2:
190 		/* static NOR */
191 		pismo_add_nor(pismo, i, &region);
192 		break;
193 	case 3:
194 		/* static RAM */
195 		pismo_add_sram(pismo, i, &region);
196 		break;
197 	}
198 }
199 
200 static int pismo_remove(struct i2c_client *client)
201 {
202 	struct pismo_data *pismo = i2c_get_clientdata(client);
203 	int i;
204 
205 	for (i = 0; i < ARRAY_SIZE(pismo->dev); i++)
206 		platform_device_unregister(pismo->dev[i]);
207 
208 	kfree(pismo);
209 
210 	return 0;
211 }
212 
213 static int pismo_probe(struct i2c_client *client,
214 				 const struct i2c_device_id *id)
215 {
216 	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
217 	struct pismo_pdata *pdata = client->dev.platform_data;
218 	struct pismo_eeprom eeprom;
219 	struct pismo_data *pismo;
220 	int ret, i;
221 
222 	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
223 		dev_err(&client->dev, "functionality mismatch\n");
224 		return -EIO;
225 	}
226 
227 	pismo = kzalloc(sizeof(*pismo), GFP_KERNEL);
228 	if (!pismo)
229 		return -ENOMEM;
230 
231 	pismo->client = client;
232 	if (pdata) {
233 		pismo->vpp = pdata->set_vpp;
234 		pismo->vpp_data = pdata->vpp_data;
235 	}
236 	i2c_set_clientdata(client, pismo);
237 
238 	ret = pismo_eeprom_read(client, &eeprom, 0, sizeof(eeprom));
239 	if (ret < 0) {
240 		dev_err(&client->dev, "error reading EEPROM: %d\n", ret);
241 		goto exit_free;
242 	}
243 
244 	dev_info(&client->dev, "%.15s board found\n", eeprom.board);
245 
246 	for (i = 0; i < ARRAY_SIZE(eeprom.cs); i++)
247 		if (eeprom.cs[i].type != 0xff)
248 			pismo_add_one(pismo, i, &eeprom.cs[i],
249 				      pdata->cs_addrs[i]);
250 
251 	return 0;
252 
253  exit_free:
254 	kfree(pismo);
255 	return ret;
256 }
257 
258 static const struct i2c_device_id pismo_id[] = {
259 	{ "pismo" },
260 	{ },
261 };
262 MODULE_DEVICE_TABLE(i2c, pismo_id);
263 
264 static struct i2c_driver pismo_driver = {
265 	.driver	= {
266 		.name	= "pismo",
267 		.owner	= THIS_MODULE,
268 	},
269 	.probe		= pismo_probe,
270 	.remove		= pismo_remove,
271 	.id_table	= pismo_id,
272 };
273 
274 static int __init pismo_init(void)
275 {
276 	BUILD_BUG_ON(sizeof(struct pismo_cs_block) != 48);
277 	BUILD_BUG_ON(sizeof(struct pismo_eeprom) != 256);
278 
279 	return i2c_add_driver(&pismo_driver);
280 }
281 module_init(pismo_init);
282 
283 static void __exit pismo_exit(void)
284 {
285 	i2c_del_driver(&pismo_driver);
286 }
287 module_exit(pismo_exit);
288 
289 MODULE_AUTHOR("Russell King <linux@arm.linux.org.uk>");
290 MODULE_DESCRIPTION("PISMO memory driver");
291 MODULE_LICENSE("GPL");
292