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1cbb4a1c CB |
1 | /* |
2 | * OPAL PNOR flash MTD abstraction | |
3 | * | |
4 | * Copyright IBM 2015 | |
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, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | */ | |
16 | ||
17 | #include <linux/kernel.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/errno.h> | |
20 | #include <linux/of.h> | |
21 | #include <linux/of_address.h> | |
22 | #include <linux/platform_device.h> | |
23 | #include <linux/string.h> | |
24 | #include <linux/slab.h> | |
25 | #include <linux/mtd/mtd.h> | |
26 | #include <linux/mtd/partitions.h> | |
27 | ||
28 | #include <linux/debugfs.h> | |
29 | #include <linux/seq_file.h> | |
30 | ||
31 | #include <asm/opal.h> | |
32 | ||
33 | ||
34 | /* | |
35 | * This driver creates the a Linux MTD abstraction for platform PNOR flash | |
36 | * backed by OPAL calls | |
37 | */ | |
38 | ||
39 | struct powernv_flash { | |
40 | struct mtd_info mtd; | |
41 | u32 id; | |
42 | }; | |
43 | ||
44 | enum flash_op { | |
45 | FLASH_OP_READ, | |
46 | FLASH_OP_WRITE, | |
47 | FLASH_OP_ERASE, | |
48 | }; | |
49 | ||
efe69414 CB |
50 | /* |
51 | * Don't return -ERESTARTSYS if we can't get a token, the MTD core | |
52 | * might have split up the call from userspace and called into the | |
53 | * driver more than once, we'll already have done some amount of work. | |
54 | */ | |
1cbb4a1c CB |
55 | static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op, |
56 | loff_t offset, size_t len, size_t *retlen, u_char *buf) | |
57 | { | |
58 | struct powernv_flash *info = (struct powernv_flash *)mtd->priv; | |
59 | struct device *dev = &mtd->dev; | |
60 | int token; | |
61 | struct opal_msg msg; | |
62 | int rc; | |
63 | ||
64 | dev_dbg(dev, "%s(op=%d, offset=0x%llx, len=%zu)\n", | |
65 | __func__, op, offset, len); | |
66 | ||
67 | token = opal_async_get_token_interruptible(); | |
68 | if (token < 0) { | |
69 | if (token != -ERESTARTSYS) | |
70 | dev_err(dev, "Failed to get an async token\n"); | |
efe69414 CB |
71 | else |
72 | token = -EINTR; | |
1cbb4a1c CB |
73 | return token; |
74 | } | |
75 | ||
76 | switch (op) { | |
77 | case FLASH_OP_READ: | |
78 | rc = opal_flash_read(info->id, offset, __pa(buf), len, token); | |
79 | break; | |
80 | case FLASH_OP_WRITE: | |
81 | rc = opal_flash_write(info->id, offset, __pa(buf), len, token); | |
82 | break; | |
83 | case FLASH_OP_ERASE: | |
84 | rc = opal_flash_erase(info->id, offset, len, token); | |
85 | break; | |
86 | default: | |
44e2aa2b CB |
87 | WARN_ON_ONCE(1); |
88 | opal_async_release_token(token); | |
89 | return -EIO; | |
1cbb4a1c CB |
90 | } |
91 | ||
6f469b67 CB |
92 | if (rc == OPAL_ASYNC_COMPLETION) { |
93 | rc = opal_async_wait_response_interruptible(token, &msg); | |
94 | if (rc) { | |
95 | /* | |
96 | * If we return the mtd core will free the | |
97 | * buffer we've just passed to OPAL but OPAL | |
98 | * will continue to read or write from that | |
99 | * memory. | |
100 | * It may be tempting to ultimately return 0 | |
101 | * if we're doing a read or a write since we | |
102 | * are going to end up waiting until OPAL is | |
103 | * done. However, because the MTD core sends | |
104 | * us the userspace request in chunks, we need | |
105 | * it to know we've been interrupted. | |
106 | */ | |
107 | rc = -EINTR; | |
108 | if (opal_async_wait_response(token, &msg)) | |
109 | dev_err(dev, "opal_async_wait_response() failed\n"); | |
110 | goto out; | |
111 | } | |
112 | rc = opal_get_async_rc(msg); | |
113 | } | |
25ee52e6 | 114 | |
6f469b67 CB |
115 | /* |
116 | * OPAL does mutual exclusion on the flash, it will return | |
117 | * OPAL_BUSY. | |
118 | * During firmware updates by the service processor OPAL may | |
119 | * be (temporarily) prevented from accessing the flash, in | |
120 | * this case OPAL will also return OPAL_BUSY. | |
121 | * Both cases aren't errors exactly but the flash could have | |
122 | * changed, userspace should be informed. | |
123 | */ | |
124 | if (rc != OPAL_SUCCESS && rc != OPAL_BUSY) | |
1cbb4a1c CB |
125 | dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n", |
126 | op, rc); | |
1cbb4a1c | 127 | |
6f469b67 CB |
128 | if (rc == OPAL_SUCCESS && retlen) |
129 | *retlen = len; | |
1cbb4a1c | 130 | |
6f469b67 | 131 | rc = opal_error_code(rc); |
25ee52e6 CB |
132 | out: |
133 | opal_async_release_token(token); | |
1cbb4a1c CB |
134 | return rc; |
135 | } | |
136 | ||
137 | /** | |
138 | * @mtd: the device | |
139 | * @from: the offset to read from | |
140 | * @len: the number of bytes to read | |
141 | * @retlen: the number of bytes actually read | |
142 | * @buf: the filled in buffer | |
143 | * | |
144 | * Returns 0 if read successful, or -ERRNO if an error occurred | |
145 | */ | |
146 | static int powernv_flash_read(struct mtd_info *mtd, loff_t from, size_t len, | |
147 | size_t *retlen, u_char *buf) | |
148 | { | |
149 | return powernv_flash_async_op(mtd, FLASH_OP_READ, from, | |
150 | len, retlen, buf); | |
151 | } | |
152 | ||
153 | /** | |
154 | * @mtd: the device | |
155 | * @to: the offset to write to | |
156 | * @len: the number of bytes to write | |
157 | * @retlen: the number of bytes actually written | |
158 | * @buf: the buffer to get bytes from | |
159 | * | |
160 | * Returns 0 if write successful, -ERRNO if error occurred | |
161 | */ | |
162 | static int powernv_flash_write(struct mtd_info *mtd, loff_t to, size_t len, | |
163 | size_t *retlen, const u_char *buf) | |
164 | { | |
165 | return powernv_flash_async_op(mtd, FLASH_OP_WRITE, to, | |
166 | len, retlen, (u_char *)buf); | |
167 | } | |
168 | ||
169 | /** | |
170 | * @mtd: the device | |
171 | * @erase: the erase info | |
172 | * Returns 0 if erase successful or -ERRNO if an error occurred | |
173 | */ | |
174 | static int powernv_flash_erase(struct mtd_info *mtd, struct erase_info *erase) | |
175 | { | |
176 | int rc; | |
177 | ||
1cbb4a1c CB |
178 | rc = powernv_flash_async_op(mtd, FLASH_OP_ERASE, erase->addr, |
179 | erase->len, NULL, NULL); | |
e7bfb3fd | 180 | if (rc) |
1cbb4a1c | 181 | erase->fail_addr = erase->addr; |
e7bfb3fd | 182 | |
1cbb4a1c CB |
183 | return rc; |
184 | } | |
185 | ||
186 | /** | |
187 | * powernv_flash_set_driver_info - Fill the mtd_info structure and docg3 | |
188 | * structure @pdev: The platform device | |
189 | * @mtd: The structure to fill | |
190 | */ | |
191 | static int powernv_flash_set_driver_info(struct device *dev, | |
192 | struct mtd_info *mtd) | |
193 | { | |
194 | u64 size; | |
195 | u32 erase_size; | |
196 | int rc; | |
197 | ||
198 | rc = of_property_read_u32(dev->of_node, "ibm,flash-block-size", | |
199 | &erase_size); | |
200 | if (rc) { | |
201 | dev_err(dev, "couldn't get resource block size information\n"); | |
202 | return rc; | |
203 | } | |
204 | ||
205 | rc = of_property_read_u64(dev->of_node, "reg", &size); | |
206 | if (rc) { | |
207 | dev_err(dev, "couldn't get resource size information\n"); | |
208 | return rc; | |
209 | } | |
210 | ||
211 | /* | |
212 | * Going to have to check what details I need to set and how to | |
213 | * get them | |
214 | */ | |
acfe63ec | 215 | mtd->name = devm_kasprintf(dev, GFP_KERNEL, "%pOFn", dev->of_node); |
1cbb4a1c CB |
216 | mtd->type = MTD_NORFLASH; |
217 | mtd->flags = MTD_WRITEABLE; | |
218 | mtd->size = size; | |
219 | mtd->erasesize = erase_size; | |
220 | mtd->writebufsize = mtd->writesize = 1; | |
221 | mtd->owner = THIS_MODULE; | |
222 | mtd->_erase = powernv_flash_erase; | |
223 | mtd->_read = powernv_flash_read; | |
224 | mtd->_write = powernv_flash_write; | |
225 | mtd->dev.parent = dev; | |
9ea97a7d | 226 | mtd_set_of_node(mtd, dev->of_node); |
1cbb4a1c CB |
227 | return 0; |
228 | } | |
229 | ||
230 | /** | |
231 | * powernv_flash_probe | |
232 | * @pdev: platform device | |
233 | * | |
234 | * Returns 0 on success, -ENOMEM, -ENXIO on error | |
235 | */ | |
236 | static int powernv_flash_probe(struct platform_device *pdev) | |
237 | { | |
238 | struct device *dev = &pdev->dev; | |
239 | struct powernv_flash *data; | |
240 | int ret; | |
241 | ||
242 | data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); | |
e32ec15a CB |
243 | if (!data) |
244 | return -ENOMEM; | |
245 | ||
1cbb4a1c CB |
246 | data->mtd.priv = data; |
247 | ||
248 | ret = of_property_read_u32(dev->of_node, "ibm,opal-id", &(data->id)); | |
249 | if (ret) { | |
250 | dev_err(dev, "no device property 'ibm,opal-id'\n"); | |
e32ec15a | 251 | return ret; |
1cbb4a1c CB |
252 | } |
253 | ||
254 | ret = powernv_flash_set_driver_info(dev, &data->mtd); | |
255 | if (ret) | |
e32ec15a | 256 | return ret; |
1cbb4a1c CB |
257 | |
258 | dev_set_drvdata(dev, data); | |
259 | ||
260 | /* | |
261 | * The current flash that skiboot exposes is one contiguous flash chip | |
262 | * with an ffs partition at the start, it should prove easier for users | |
263 | * to deal with partitions or not as they see fit | |
264 | */ | |
e32ec15a | 265 | return mtd_device_register(&data->mtd, NULL, 0); |
1cbb4a1c CB |
266 | } |
267 | ||
268 | /** | |
269 | * op_release - Release the driver | |
270 | * @pdev: the platform device | |
271 | * | |
272 | * Returns 0 | |
273 | */ | |
274 | static int powernv_flash_release(struct platform_device *pdev) | |
275 | { | |
276 | struct powernv_flash *data = dev_get_drvdata(&(pdev->dev)); | |
277 | ||
278 | /* All resources should be freed automatically */ | |
279 | return mtd_device_unregister(&(data->mtd)); | |
280 | } | |
281 | ||
282 | static const struct of_device_id powernv_flash_match[] = { | |
283 | { .compatible = "ibm,opal-flash" }, | |
284 | {} | |
285 | }; | |
286 | ||
287 | static struct platform_driver powernv_flash_driver = { | |
288 | .driver = { | |
289 | .name = "powernv_flash", | |
290 | .of_match_table = powernv_flash_match, | |
291 | }, | |
292 | .remove = powernv_flash_release, | |
293 | .probe = powernv_flash_probe, | |
294 | }; | |
295 | ||
296 | module_platform_driver(powernv_flash_driver); | |
297 | ||
298 | MODULE_DEVICE_TABLE(of, powernv_flash_match); | |
299 | MODULE_LICENSE("GPL"); | |
300 | MODULE_AUTHOR("Cyril Bur <cyril.bur@au1.ibm.com>"); | |
301 | MODULE_DESCRIPTION("MTD abstraction for OPAL flash"); |