projects/linux·blob master · refs

445 lines · 9.0 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) ???? Jochen Schäuble <[email protected]>
4 * Copyright (c) 2003-2004 Joern Engel <[email protected]>
5 *
6 * Usage:
7 *
8 * one commend line parameter per device, each in the form:
9 * phram=<name>,<start>,<len>[,<erasesize>]
10 * <name> may be up to 63 characters.
11 * <start>, <len>, and <erasesize> can be octal, decimal or hexadecimal. If followed
12 * by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
13 * gigabytes. <erasesize> is optional and defaults to PAGE_SIZE.
14 *
15 * Example:
16 * phram=swap,64Mi,128Mi phram=test,900Mi,1Mi,64Ki
17 */
18
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/io.h>
22#include <linux/init.h>
23#include <linux/kernel.h>
24#include <linux/list.h>
25#include <linux/module.h>
26#include <linux/moduleparam.h>
27#include <linux/slab.h>
28#include <linux/mtd/mtd.h>
29#include <asm/div64.h>
30#include <linux/platform_device.h>
31#include <linux/of_address.h>
32#include <linux/of.h>
33#include <linux/security.h>
34
35struct phram_mtd_list {
36 struct mtd_info mtd;
37 struct list_head list;
38 bool cached;
39};
40
41static LIST_HEAD(phram_list);
42
43static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
44{
45 u_char *start = mtd->priv;
46
47 memset(start + instr->addr, 0xff, instr->len);
48
49 return 0;
50}
51
52static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
53 size_t *retlen, void **virt, resource_size_t *phys)
54{
55 *virt = mtd->priv + from;
56 *retlen = len;
57 return 0;
58}
59
60static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
61{
62 return 0;
63}
64
65static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
66 size_t *retlen, u_char *buf)
67{
68 u_char *start = mtd->priv;
69
70 memcpy(buf, start + from, len);
71 *retlen = len;
72 return 0;
73}
74
75static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
76 size_t *retlen, const u_char *buf)
77{
78 u_char *start = mtd->priv;
79
80 memcpy(start + to, buf, len);
81 *retlen = len;
82 return 0;
83}
84
85static int phram_map(struct phram_mtd_list *phram, phys_addr_t start, size_t len)
86{
87 void *addr = NULL;
88
89 if (phram->cached)
90 addr = memremap(start, len, MEMREMAP_WB);
91 else
92 addr = (void __force *)ioremap(start, len);
93 if (!addr)
94 return -EIO;
95
96 phram->mtd.priv = addr;
97
98 return 0;
99}
100
101static void phram_unmap(struct phram_mtd_list *phram)
102{
103 void *addr = phram->mtd.priv;
104
105 if (phram->cached) {
106 memunmap(addr);
107 return;
108 }
109
110 iounmap((void __iomem *)addr);
111}
112
113static void unregister_devices(void)
114{
115 struct phram_mtd_list *this, *safe;
116
117 list_for_each_entry_safe(this, safe, &phram_list, list) {
118 mtd_device_unregister(&this->mtd);
119 phram_unmap(this);
120 kfree(this->mtd.name);
121 kfree(this);
122 }
123}
124
125static int register_device(struct platform_device *pdev, const char *name,
126 phys_addr_t start, size_t len, uint32_t erasesize)
127{
128 struct device_node *np = pdev ? pdev->dev.of_node : NULL;
129 bool cached = np ? !of_property_read_bool(np, "no-map") : false;
130 struct phram_mtd_list *new;
131 int ret = -ENOMEM;
132
133 new = kzalloc_obj(*new);
134 if (!new)
135 goto out0;
136
137 new->cached = cached;
138
139 ret = phram_map(new, start, len);
140 if (ret) {
141 pr_err("ioremap failed\n");
142 goto out1;
143 }
144
145
146 new->mtd.name = name;
147 new->mtd.size = len;
148 new->mtd.flags = MTD_CAP_RAM;
149 new->mtd._erase = phram_erase;
150 new->mtd._point = phram_point;
151 new->mtd._unpoint = phram_unpoint;
152 new->mtd._read = phram_read;
153 new->mtd._write = phram_write;
154 new->mtd.owner = THIS_MODULE;
155 new->mtd.type = MTD_RAM;
156 new->mtd.erasesize = erasesize;
157 new->mtd.writesize = 1;
158
159 mtd_set_of_node(&new->mtd, np);
160
161 ret = -EAGAIN;
162 if (mtd_device_register(&new->mtd, NULL, 0)) {
163 pr_err("Failed to register new device\n");
164 goto out2;
165 }
166
167 if (pdev)
168 platform_set_drvdata(pdev, new);
169 else
170 list_add_tail(&new->list, &phram_list);
171
172 return 0;
173
174out2:
175 phram_unmap(new);
176out1:
177 kfree(new);
178out0:
179 return ret;
180}
181
182static int parse_num64(uint64_t *num64, char *token)
183{
184 size_t len;
185 int shift = 0;
186 int ret;
187
188 len = strlen(token);
189 /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
190 if (len > 2) {
191 if (token[len - 1] == 'i') {
192 switch (token[len - 2]) {
193 case 'G':
194 shift += 10;
195 fallthrough;
196 case 'M':
197 shift += 10;
198 fallthrough;
199 case 'k':
200 shift += 10;
201 token[len - 2] = 0;
202 break;
203 default:
204 return -EINVAL;
205 }
206 }
207 }
208
209 ret = kstrtou64(token, 0, num64);
210 *num64 <<= shift;
211
212 return ret;
213}
214
215static int parse_name(char **pname, const char *token)
216{
217 size_t len;
218 char *name;
219
220 len = strlen(token) + 1;
221 if (len > 64)
222 return -ENOSPC;
223
224 name = kstrdup(token, GFP_KERNEL);
225 if (!name)
226 return -ENOMEM;
227
228 *pname = name;
229 return 0;
230}
231
232
233static inline void kill_final_newline(char *str)
234{
235 char *newline = strrchr(str, '\n');
236
237 if (newline && !newline[1])
238 *newline = 0;
239}
240
241
242#define parse_err(fmt, args...) do { \
243 pr_err(fmt , ## args); \
244 return 1; \
245} while (0)
246
247#ifndef MODULE
248static int phram_init_called;
249/*
250 * This shall contain the module parameter if any. It is of the form:
251 * - phram=<device>,<address>,<size>[,<erasesize>] for module case
252 * - phram.phram=<device>,<address>,<size>[,<erasesize>] for built-in case
253 * We leave 64 bytes for the device name, 20 for the address , 20 for the
254 * size and 20 for the erasesize.
255 * Example: phram.phram=rootfs,0xa0000000,512Mi,65536
256 */
257static char phram_paramline[64 + 20 + 20 + 20];
258#endif
259
260static int phram_setup(const char *val)
261{
262 char buf[64 + 20 + 20 + 20], *str = buf;
263 char *token[4];
264 char *name;
265 uint64_t start;
266 uint64_t len;
267 uint64_t erasesize = PAGE_SIZE;
268 uint32_t rem;
269 int i, ret;
270
271 if (strnlen(val, sizeof(buf)) >= sizeof(buf))
272 parse_err("parameter too long\n");
273
274 strcpy(str, val);
275 kill_final_newline(str);
276
277 for (i = 0; i < 4; i++)
278 token[i] = strsep(&str, ",");
279
280 if (str)
281 parse_err("too many arguments\n");
282
283 if (!token[2])
284 parse_err("not enough arguments\n");
285
286 ret = parse_name(&name, token[0]);
287 if (ret)
288 return ret;
289
290 ret = parse_num64(&start, token[1]);
291 if (ret) {
292 parse_err("illegal start address\n");
293 goto error;
294 }
295
296 ret = parse_num64(&len, token[2]);
297 if (ret) {
298 parse_err("illegal device length\n");
299 goto error;
300 }
301
302 if (token[3]) {
303 ret = parse_num64(&erasesize, token[3]);
304 if (ret) {
305 parse_err("illegal erasesize\n");
306 goto error;
307 }
308 }
309
310 if (len == 0 || erasesize == 0 || erasesize > len
311 || erasesize > UINT_MAX) {
312 parse_err("illegal erasesize or len\n");
313 ret = -EINVAL;
314 goto error;
315 }
316
317 div_u64_rem(len, (uint32_t)erasesize, &rem);
318 if (rem) {
319 parse_err("len is not multiple of erasesize\n");
320 ret = -EINVAL;
321 goto error;
322 }
323
324 ret = register_device(NULL, name, start, len, (uint32_t)erasesize);
325 if (ret)
326 goto error;
327
328 pr_info("%s device: %#llx at %#llx for erasesize %#llx\n", name, len, start, erasesize);
329 return 0;
330
331error:
332 kfree(name);
333 return ret;
334}
335
336static int phram_param_call(const char *val, const struct kernel_param *kp)
337{
338#ifdef MODULE
339 return phram_setup(val);
340#else
341 /*
342 * If more parameters are later passed in via
343 * /sys/module/phram/parameters/phram
344 * and init_phram() has already been called,
345 * we can parse the argument now.
346 */
347
348 if (phram_init_called)
349 return phram_setup(val);
350
351 /*
352 * During early boot stage, we only save the parameters
353 * here. We must parse them later: if the param passed
354 * from kernel boot command line, phram_param_call() is
355 * called so early that it is not possible to resolve
356 * the device (even kmalloc() fails). Defer that work to
357 * phram_setup().
358 */
359
360 if (strlen(val) >= sizeof(phram_paramline))
361 return -ENOSPC;
362 strcpy(phram_paramline, val);
363
364 return 0;
365#endif
366}
367
368module_param_call(phram, phram_param_call, NULL, NULL, 0200);
369MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>[,<erasesize>]\"");
370
371#ifdef CONFIG_OF
372static const struct of_device_id phram_of_match[] = {
373 { .compatible = "phram" },
374 {}
375};
376MODULE_DEVICE_TABLE(of, phram_of_match);
377#endif
378
379static int phram_probe(struct platform_device *pdev)
380{
381 struct resource *res;
382
383 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
384 if (!res)
385 return -ENOMEM;
386
387 /* mtd_set_of_node() reads name from "label" */
388 return register_device(pdev, NULL, res->start, resource_size(res),
389 PAGE_SIZE);
390}
391
392static void phram_remove(struct platform_device *pdev)
393{
394 struct phram_mtd_list *phram = platform_get_drvdata(pdev);
395
396 mtd_device_unregister(&phram->mtd);
397 phram_unmap(phram);
398 kfree(phram);
399}
400
401static struct platform_driver phram_driver = {
402 .probe = phram_probe,
403 .remove = phram_remove,
404 .driver = {
405 .name = "phram",
406 .of_match_table = of_match_ptr(phram_of_match),
407 },
408};
409
410static int __init init_phram(void)
411{
412 int ret;
413
414 ret = security_locked_down(LOCKDOWN_DEV_MEM);
415 if (ret)
416 return ret;
417
418 ret = platform_driver_register(&phram_driver);
419 if (ret)
420 return ret;
421
422#ifndef MODULE
423 if (phram_paramline[0]) {
424 ret = phram_setup(phram_paramline);
425 if (ret)
426 platform_driver_unregister(&phram_driver);
427 }
428 phram_init_called = 1;
429#endif
430
431 return ret;
432}
433
434static void __exit cleanup_phram(void)
435{
436 unregister_devices();
437 platform_driver_unregister(&phram_driver);
438}
439
440module_init(init_phram);
441module_exit(cleanup_phram);
442
443MODULE_LICENSE("GPL");
444MODULE_AUTHOR("Joern Engel <[email protected]>");
445MODULE_DESCRIPTION("MTD driver for physical RAM");