1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * OPAL PNOR flash MTD abstraction |
4 | * |
5 | * Copyright IBM 2015 |
6 | */ |
7 | |
8 | #include <linux/kernel.h> |
9 | #include <linux/module.h> |
10 | #include <linux/errno.h> |
11 | #include <linux/of.h> |
12 | #include <linux/of_address.h> |
13 | #include <linux/platform_device.h> |
14 | #include <linux/string.h> |
15 | #include <linux/slab.h> |
16 | #include <linux/mtd/mtd.h> |
17 | #include <linux/mtd/partitions.h> |
18 | |
19 | #include <linux/debugfs.h> |
20 | #include <linux/seq_file.h> |
21 | |
22 | #include <asm/opal.h> |
23 | |
24 | |
25 | /* |
26 | * This driver creates the a Linux MTD abstraction for platform PNOR flash |
27 | * backed by OPAL calls |
28 | */ |
29 | |
30 | struct powernv_flash { |
31 | struct mtd_info mtd; |
32 | u32 id; |
33 | }; |
34 | |
35 | enum flash_op { |
36 | FLASH_OP_READ, |
37 | FLASH_OP_WRITE, |
38 | FLASH_OP_ERASE, |
39 | }; |
40 | |
41 | /* |
42 | * Don't return -ERESTARTSYS if we can't get a token, the MTD core |
43 | * might have split up the call from userspace and called into the |
44 | * driver more than once, we'll already have done some amount of work. |
45 | */ |
46 | static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op, |
47 | loff_t offset, size_t len, size_t *retlen, u_char *buf) |
48 | { |
49 | struct powernv_flash *info = (struct powernv_flash *)mtd->priv; |
50 | struct device *dev = &mtd->dev; |
51 | int token; |
52 | struct opal_msg msg; |
53 | int rc; |
54 | |
55 | dev_dbg(dev, "%s(op=%d, offset=0x%llx, len=%zu)\n" , |
56 | __func__, op, offset, len); |
57 | |
58 | token = opal_async_get_token_interruptible(); |
59 | if (token < 0) { |
60 | if (token != -ERESTARTSYS) |
61 | dev_err(dev, "Failed to get an async token\n" ); |
62 | else |
63 | token = -EINTR; |
64 | return token; |
65 | } |
66 | |
67 | switch (op) { |
68 | case FLASH_OP_READ: |
69 | rc = opal_flash_read(info->id, offset, __pa(buf), len, token); |
70 | break; |
71 | case FLASH_OP_WRITE: |
72 | rc = opal_flash_write(info->id, offset, __pa(buf), len, token); |
73 | break; |
74 | case FLASH_OP_ERASE: |
75 | rc = opal_flash_erase(info->id, offset, len, token); |
76 | break; |
77 | default: |
78 | WARN_ON_ONCE(1); |
79 | opal_async_release_token(token); |
80 | return -EIO; |
81 | } |
82 | |
83 | if (rc == OPAL_ASYNC_COMPLETION) { |
84 | rc = opal_async_wait_response_interruptible(token, &msg); |
85 | if (rc) { |
86 | /* |
87 | * If we return the mtd core will free the |
88 | * buffer we've just passed to OPAL but OPAL |
89 | * will continue to read or write from that |
90 | * memory. |
91 | * It may be tempting to ultimately return 0 |
92 | * if we're doing a read or a write since we |
93 | * are going to end up waiting until OPAL is |
94 | * done. However, because the MTD core sends |
95 | * us the userspace request in chunks, we need |
96 | * it to know we've been interrupted. |
97 | */ |
98 | rc = -EINTR; |
99 | if (opal_async_wait_response(token, &msg)) |
100 | dev_err(dev, "opal_async_wait_response() failed\n" ); |
101 | goto out; |
102 | } |
103 | rc = opal_get_async_rc(msg); |
104 | } |
105 | |
106 | /* |
107 | * OPAL does mutual exclusion on the flash, it will return |
108 | * OPAL_BUSY. |
109 | * During firmware updates by the service processor OPAL may |
110 | * be (temporarily) prevented from accessing the flash, in |
111 | * this case OPAL will also return OPAL_BUSY. |
112 | * Both cases aren't errors exactly but the flash could have |
113 | * changed, userspace should be informed. |
114 | */ |
115 | if (rc != OPAL_SUCCESS && rc != OPAL_BUSY) |
116 | dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n" , |
117 | op, rc); |
118 | |
119 | if (rc == OPAL_SUCCESS && retlen) |
120 | *retlen = len; |
121 | |
122 | rc = opal_error_code(rc); |
123 | out: |
124 | opal_async_release_token(token); |
125 | return rc; |
126 | } |
127 | |
128 | /** |
129 | * powernv_flash_read |
130 | * @mtd: the device |
131 | * @from: the offset to read from |
132 | * @len: the number of bytes to read |
133 | * @retlen: the number of bytes actually read |
134 | * @buf: the filled in buffer |
135 | * |
136 | * Returns 0 if read successful, or -ERRNO if an error occurred |
137 | */ |
138 | static int powernv_flash_read(struct mtd_info *mtd, loff_t from, size_t len, |
139 | size_t *retlen, u_char *buf) |
140 | { |
141 | return powernv_flash_async_op(mtd, op: FLASH_OP_READ, offset: from, |
142 | len, retlen, buf); |
143 | } |
144 | |
145 | /** |
146 | * powernv_flash_write |
147 | * @mtd: the device |
148 | * @to: the offset to write to |
149 | * @len: the number of bytes to write |
150 | * @retlen: the number of bytes actually written |
151 | * @buf: the buffer to get bytes from |
152 | * |
153 | * Returns 0 if write successful, -ERRNO if error occurred |
154 | */ |
155 | static int powernv_flash_write(struct mtd_info *mtd, loff_t to, size_t len, |
156 | size_t *retlen, const u_char *buf) |
157 | { |
158 | return powernv_flash_async_op(mtd, op: FLASH_OP_WRITE, offset: to, |
159 | len, retlen, buf: (u_char *)buf); |
160 | } |
161 | |
162 | /** |
163 | * powernv_flash_erase |
164 | * @mtd: the device |
165 | * @erase: the erase info |
166 | * Returns 0 if erase successful or -ERRNO if an error occurred |
167 | */ |
168 | static int powernv_flash_erase(struct mtd_info *mtd, struct erase_info *erase) |
169 | { |
170 | int rc; |
171 | |
172 | rc = powernv_flash_async_op(mtd, op: FLASH_OP_ERASE, offset: erase->addr, |
173 | len: erase->len, NULL, NULL); |
174 | if (rc) |
175 | erase->fail_addr = erase->addr; |
176 | |
177 | return rc; |
178 | } |
179 | |
180 | /** |
181 | * powernv_flash_set_driver_info - Fill the mtd_info structure and docg3 |
182 | * @dev: The device structure |
183 | * @mtd: The structure to fill |
184 | */ |
185 | static int powernv_flash_set_driver_info(struct device *dev, |
186 | struct mtd_info *mtd) |
187 | { |
188 | u64 size; |
189 | u32 erase_size; |
190 | int rc; |
191 | |
192 | rc = of_property_read_u32(np: dev->of_node, propname: "ibm,flash-block-size" , |
193 | out_value: &erase_size); |
194 | if (rc) { |
195 | dev_err(dev, "couldn't get resource block size information\n" ); |
196 | return rc; |
197 | } |
198 | |
199 | rc = of_property_read_u64(np: dev->of_node, propname: "reg" , out_value: &size); |
200 | if (rc) { |
201 | dev_err(dev, "couldn't get resource size information\n" ); |
202 | return rc; |
203 | } |
204 | |
205 | /* |
206 | * Going to have to check what details I need to set and how to |
207 | * get them |
208 | */ |
209 | mtd->name = devm_kasprintf(dev, GFP_KERNEL, fmt: "%pOFP" , dev->of_node); |
210 | mtd->type = MTD_NORFLASH; |
211 | mtd->flags = MTD_WRITEABLE; |
212 | mtd->size = size; |
213 | mtd->erasesize = erase_size; |
214 | mtd->writebufsize = mtd->writesize = 1; |
215 | mtd->owner = THIS_MODULE; |
216 | mtd->_erase = powernv_flash_erase; |
217 | mtd->_read = powernv_flash_read; |
218 | mtd->_write = powernv_flash_write; |
219 | mtd->dev.parent = dev; |
220 | mtd_set_of_node(mtd, np: dev->of_node); |
221 | return 0; |
222 | } |
223 | |
224 | /** |
225 | * powernv_flash_probe |
226 | * @pdev: platform device |
227 | * |
228 | * Returns 0 on success, -ENOMEM, -ENXIO on error |
229 | */ |
230 | static int powernv_flash_probe(struct platform_device *pdev) |
231 | { |
232 | struct device *dev = &pdev->dev; |
233 | struct powernv_flash *data; |
234 | int ret; |
235 | |
236 | data = devm_kzalloc(dev, size: sizeof(*data), GFP_KERNEL); |
237 | if (!data) |
238 | return -ENOMEM; |
239 | |
240 | data->mtd.priv = data; |
241 | |
242 | ret = of_property_read_u32(np: dev->of_node, propname: "ibm,opal-id" , out_value: &(data->id)); |
243 | if (ret) { |
244 | dev_err(dev, "no device property 'ibm,opal-id'\n" ); |
245 | return ret; |
246 | } |
247 | |
248 | ret = powernv_flash_set_driver_info(dev, mtd: &data->mtd); |
249 | if (ret) |
250 | return ret; |
251 | |
252 | dev_set_drvdata(dev, data); |
253 | |
254 | /* |
255 | * The current flash that skiboot exposes is one contiguous flash chip |
256 | * with an ffs partition at the start, it should prove easier for users |
257 | * to deal with partitions or not as they see fit |
258 | */ |
259 | return mtd_device_register(&data->mtd, NULL, 0); |
260 | } |
261 | |
262 | /** |
263 | * op_release - Release the driver |
264 | * @pdev: the platform device |
265 | * |
266 | * Returns 0 |
267 | */ |
268 | static void powernv_flash_release(struct platform_device *pdev) |
269 | { |
270 | struct powernv_flash *data = dev_get_drvdata(dev: &(pdev->dev)); |
271 | |
272 | /* All resources should be freed automatically */ |
273 | WARN_ON(mtd_device_unregister(&data->mtd)); |
274 | } |
275 | |
276 | static const struct of_device_id powernv_flash_match[] = { |
277 | { .compatible = "ibm,opal-flash" }, |
278 | {} |
279 | }; |
280 | |
281 | static struct platform_driver powernv_flash_driver = { |
282 | .driver = { |
283 | .name = "powernv_flash" , |
284 | .of_match_table = powernv_flash_match, |
285 | }, |
286 | .remove_new = powernv_flash_release, |
287 | .probe = powernv_flash_probe, |
288 | }; |
289 | |
290 | module_platform_driver(powernv_flash_driver); |
291 | |
292 | MODULE_DEVICE_TABLE(of, powernv_flash_match); |
293 | MODULE_LICENSE("GPL" ); |
294 | MODULE_AUTHOR("Cyril Bur <cyril.bur@au1.ibm.com>" ); |
295 | MODULE_DESCRIPTION("MTD abstraction for OPAL flash" ); |
296 | |