1 /*
2 * drivers/mtd/nand/socrates_nand.c
3 *
4 * Copyright © 2008 Ilya Yanok, Emcraft Systems
5 *
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 */
12
13 #include <linux/slab.h>
14 #include <linux/module.h>
15 #include <linux/mtd/mtd.h>
16 #include <linux/mtd/nand.h>
17 #include <linux/mtd/partitions.h>
18 #include <linux/of_platform.h>
19 #include <linux/io.h>
20
21 #define FPGA_NAND_CMD_MASK (0x7 << 28)
22 #define FPGA_NAND_CMD_COMMAND (0x0 << 28)
23 #define FPGA_NAND_CMD_ADDR (0x1 << 28)
24 #define FPGA_NAND_CMD_READ (0x2 << 28)
25 #define FPGA_NAND_CMD_WRITE (0x3 << 28)
26 #define FPGA_NAND_BUSY (0x1 << 15)
27 #define FPGA_NAND_ENABLE (0x1 << 31)
28 #define FPGA_NAND_DATA_SHIFT 16
29
30 struct socrates_nand_host {
31 struct nand_chip nand_chip;
32 struct mtd_info mtd;
33 void __iomem *io_base;
34 struct device *dev;
35 };
36
37 /**
38 * socrates_nand_write_buf - write buffer to chip
39 * @mtd: MTD device structure
40 * @buf: data buffer
41 * @len: number of bytes to write
42 */
43 static void socrates_nand_write_buf(struct mtd_info *mtd,
44 const uint8_t *buf, int len)
45 {
46 int i;
47 struct nand_chip *this = mtd->priv;
48 struct socrates_nand_host *host = this->priv;
49
50 for (i = 0; i < len; i++) {
51 out_be32(host->io_base, FPGA_NAND_ENABLE |
52 FPGA_NAND_CMD_WRITE |
53 (buf[i] << FPGA_NAND_DATA_SHIFT));
54 }
55 }
56
57 /**
58 * socrates_nand_read_buf - read chip data into buffer
59 * @mtd: MTD device structure
60 * @buf: buffer to store date
61 * @len: number of bytes to read
62 */
63 static void socrates_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
64 {
65 int i;
66 struct nand_chip *this = mtd->priv;
67 struct socrates_nand_host *host = this->priv;
68 uint32_t val;
69
70 val = FPGA_NAND_ENABLE | FPGA_NAND_CMD_READ;
71
72 out_be32(host->io_base, val);
73 for (i = 0; i < len; i++) {
74 buf[i] = (in_be32(host->io_base) >>
75 FPGA_NAND_DATA_SHIFT) & 0xff;
76 }
77 }
78
79 /**
80 * socrates_nand_read_byte - read one byte from the chip
81 * @mtd: MTD device structure
82 */
83 static uint8_t socrates_nand_read_byte(struct mtd_info *mtd)
84 {
85 uint8_t byte;
86 socrates_nand_read_buf(mtd, &byte, sizeof(byte));
87 return byte;
88 }
89
90 /**
91 * socrates_nand_read_word - read one word from the chip
92 * @mtd: MTD device structure
93 */
94 static uint16_t socrates_nand_read_word(struct mtd_info *mtd)
95 {
96 uint16_t word;
97 socrates_nand_read_buf(mtd, (uint8_t *)&word, sizeof(word));
98 return word;
99 }
100
101 /**
102 * socrates_nand_verify_buf - Verify chip data against buffer
103 * @mtd: MTD device structure
104 * @buf: buffer containing the data to compare
105 * @len: number of bytes to compare
106 */
107 static int socrates_nand_verify_buf(struct mtd_info *mtd, const u8 *buf,
108 int len)
109 {
110 int i;
111
112 for (i = 0; i < len; i++) {
113 if (buf[i] != socrates_nand_read_byte(mtd))
114 return -EFAULT;
115 }
116 return 0;
117 }
118
119 /*
120 * Hardware specific access to control-lines
121 */
122 static void socrates_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
123 unsigned int ctrl)
124 {
125 struct nand_chip *nand_chip = mtd->priv;
126 struct socrates_nand_host *host = nand_chip->priv;
127 uint32_t val;
128
129 if (cmd == NAND_CMD_NONE)
130 return;
131
132 if (ctrl & NAND_CLE)
133 val = FPGA_NAND_CMD_COMMAND;
134 else
135 val = FPGA_NAND_CMD_ADDR;
136
137 if (ctrl & NAND_NCE)
138 val |= FPGA_NAND_ENABLE;
139
140 val |= (cmd & 0xff) << FPGA_NAND_DATA_SHIFT;
141
142 out_be32(host->io_base, val);
143 }
144
145 /*
146 * Read the Device Ready pin.
147 */
148 static int socrates_nand_device_ready(struct mtd_info *mtd)
149 {
150 struct nand_chip *nand_chip = mtd->priv;
151 struct socrates_nand_host *host = nand_chip->priv;
152
153 if (in_be32(host->io_base) & FPGA_NAND_BUSY)
154 return 0; /* busy */
155 return 1;
156 }
157
158 #ifdef CONFIG_MTD_PARTITIONS
159 static const char *part_probes[] = { "cmdlinepart", NULL };
160 #endif
161
162 /*
163 * Probe for the NAND device.
164 */
165 static int __devinit socrates_nand_probe(struct of_device *ofdev,
166 const struct of_device_id *ofid)
167 {
168 struct socrates_nand_host *host;
169 struct mtd_info *mtd;
170 struct nand_chip *nand_chip;
171 int res;
172
173 #ifdef CONFIG_MTD_PARTITIONS
174 struct mtd_partition *partitions = NULL;
175 int num_partitions = 0;
176 #endif
177
178 /* Allocate memory for the device structure (and zero it) */
179 host = kzalloc(sizeof(struct socrates_nand_host), GFP_KERNEL);
180 if (!host) {
181 printk(KERN_ERR
182 "socrates_nand: failed to allocate device structure.\n");
183 return -ENOMEM;
184 }
185
186 host->io_base = of_iomap(ofdev->node, 0);
187 if (host->io_base == NULL) {
188 printk(KERN_ERR "socrates_nand: ioremap failed\n");
189 kfree(host);
190 return -EIO;
191 }
192
193 mtd = &host->mtd;
194 nand_chip = &host->nand_chip;
195 host->dev = &ofdev->dev;
196
197 nand_chip->priv = host; /* link the private data structures */
198 mtd->priv = nand_chip;
199 mtd->name = "socrates_nand";
200 mtd->owner = THIS_MODULE;
201 mtd->dev.parent = &ofdev->dev;
202
203 /*should never be accessed directly */
204 nand_chip->IO_ADDR_R = (void *)0xdeadbeef;
205 nand_chip->IO_ADDR_W = (void *)0xdeadbeef;
206
207 nand_chip->cmd_ctrl = socrates_nand_cmd_ctrl;
208 nand_chip->read_byte = socrates_nand_read_byte;
209 nand_chip->read_word = socrates_nand_read_word;
210 nand_chip->write_buf = socrates_nand_write_buf;
211 nand_chip->read_buf = socrates_nand_read_buf;
212 nand_chip->verify_buf = socrates_nand_verify_buf;
213 nand_chip->dev_ready = socrates_nand_device_ready;
214
215 nand_chip->ecc.mode = NAND_ECC_SOFT; /* enable ECC */
216
217 /* TODO: I have no idea what real delay is. */
218 nand_chip->chip_delay = 20; /* 20us command delay time */
219
220 dev_set_drvdata(&ofdev->dev, host);
221
222 /* first scan to find the device and get the page size */
223 if (nand_scan_ident(mtd, 1)) {
224 res = -ENXIO;
225 goto out;
226 }
227
228 /* second phase scan */
229 if (nand_scan_tail(mtd)) {
230 res = -ENXIO;
231 goto out;
232 }
233
234 #ifdef CONFIG_MTD_PARTITIONS
235 #ifdef CONFIG_MTD_CMDLINE_PARTS
236 num_partitions = parse_mtd_partitions(mtd, part_probes,
237 &partitions, 0);
238 if (num_partitions < 0) {
239 res = num_partitions;
240 goto release;
241 }
242 #endif
243
244 #ifdef CONFIG_MTD_OF_PARTS
245 if (num_partitions == 0) {
246 num_partitions = of_mtd_parse_partitions(&ofdev->dev,
247 ofdev->node,
248 &partitions);
249 if (num_partitions < 0) {
250 res = num_partitions;
251 goto release;
252 }
253 }
254 #endif
255 if (partitions && (num_partitions > 0))
256 res = add_mtd_partitions(mtd, partitions, num_partitions);
257 else
258 #endif
259 res = add_mtd_device(mtd);
260
261 if (!res)
262 return res;
263
264 #ifdef CONFIG_MTD_PARTITIONS
265 release:
266 #endif
267 nand_release(mtd);
268
269 out:
270 dev_set_drvdata(&ofdev->dev, NULL);
271 iounmap(host->io_base);
272 kfree(host);
273 return res;
274 }
275
276 /*
277 * Remove a NAND device.
278 */
279 static int __devexit socrates_nand_remove(struct of_device *ofdev)
280 {
281 struct socrates_nand_host *host = dev_get_drvdata(&ofdev->dev);
282 struct mtd_info *mtd = &host->mtd;
283
284 nand_release(mtd);
285
286 dev_set_drvdata(&ofdev->dev, NULL);
287 iounmap(host->io_base);
288 kfree(host);
289
290 return 0;
291 }
292
293 static struct of_device_id socrates_nand_match[] =
294 {
295 {
296 .compatible = "abb,socrates-nand",
297 },
298 {},
299 };
300
301 MODULE_DEVICE_TABLE(of, socrates_nand_match);
302
303 static struct of_platform_driver socrates_nand_driver = {
304 .name = "socrates_nand",
305 .match_table = socrates_nand_match,
306 .probe = socrates_nand_probe,
307 .remove = __devexit_p(socrates_nand_remove),
308 };
309
310 static int __init socrates_nand_init(void)
311 {
312 return of_register_platform_driver(&socrates_nand_driver);
313 }
314
315 static void __exit socrates_nand_exit(void)
316 {
317 of_unregister_platform_driver(&socrates_nand_driver);
318 }
319
320 module_init(socrates_nand_init);
321 module_exit(socrates_nand_exit);
322
323 MODULE_LICENSE("GPL");
324 MODULE_AUTHOR("Ilya Yanok");
325 MODULE_DESCRIPTION("NAND driver for Socrates board");
326
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