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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) ???? Jochen Schäuble <psionic@psionic.de>
4 * Copyright (c) 2003-2004 Joern Engel <joern@wh.fh-wedel.de>
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
34struct phram_mtd_list {
35 struct mtd_info mtd;
36 struct list_head list;
37 bool cached;
38};
39
40static LIST_HEAD(phram_list);
41
42static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
43{
44 u_char *start = mtd->priv;
45
46 memset(start + instr->addr, 0xff, instr->len);
47
48 return 0;
49}
50
51static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
52 size_t *retlen, void **virt, resource_size_t *phys)
53{
54 *virt = mtd->priv + from;
55 *retlen = len;
56 return 0;
57}
58
59static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
60{
61 return 0;
62}
63
64static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
65 size_t *retlen, u_char *buf)
66{
67 u_char *start = mtd->priv;
68
69 memcpy(buf, start + from, len);
70 *retlen = len;
71 return 0;
72}
73
74static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
75 size_t *retlen, const u_char *buf)
76{
77 u_char *start = mtd->priv;
78
79 memcpy(start + to, buf, len);
80 *retlen = len;
81 return 0;
82}
83
84static int phram_map(struct phram_mtd_list *phram, phys_addr_t start, size_t len)
85{
86 void *addr = NULL;
87
88 if (phram->cached)
89 addr = memremap(start, len, MEMREMAP_WB);
90 else
91 addr = (void __force *)ioremap(start, len);
92 if (!addr)
93 return -EIO;
94
95 phram->mtd.priv = addr;
96
97 return 0;
98}
99
100static void phram_unmap(struct phram_mtd_list *phram)
101{
102 void *addr = phram->mtd.priv;
103
104 if (phram->cached) {
105 memunmap(addr);
106 return;
107 }
108
109 iounmap((void __iomem *)addr);
110}
111
112static void unregister_devices(void)
113{
114 struct phram_mtd_list *this, *safe;
115
116 list_for_each_entry_safe(this, safe, &phram_list, list) {
117 mtd_device_unregister(&this->mtd);
118 phram_unmap(this);
119 kfree(this->mtd.name);
120 kfree(this);
121 }
122}
123
124static int register_device(struct platform_device *pdev, const char *name,
125 phys_addr_t start, size_t len, uint32_t erasesize)
126{
127 struct device_node *np = pdev ? pdev->dev.of_node : NULL;
128 bool cached = np ? !of_property_read_bool(np, "no-map") : false;
129 struct phram_mtd_list *new;
130 int ret = -ENOMEM;
131
132 new = kzalloc(sizeof(*new), GFP_KERNEL);
133 if (!new)
134 goto out0;
135
136 new->cached = cached;
137
138 ret = phram_map(new, start, len);
139 if (ret) {
140 pr_err("ioremap failed\n");
141 goto out1;
142 }
143
144
145 new->mtd.name = name;
146 new->mtd.size = len;
147 new->mtd.flags = MTD_CAP_RAM;
148 new->mtd._erase = phram_erase;
149 new->mtd._point = phram_point;
150 new->mtd._unpoint = phram_unpoint;
151 new->mtd._read = phram_read;
152 new->mtd._write = phram_write;
153 new->mtd.owner = THIS_MODULE;
154 new->mtd.type = MTD_RAM;
155 new->mtd.erasesize = erasesize;
156 new->mtd.writesize = 1;
157
158 mtd_set_of_node(&new->mtd, np);
159
160 ret = -EAGAIN;
161 if (mtd_device_register(&new->mtd, NULL, 0)) {
162 pr_err("Failed to register new device\n");
163 goto out2;
164 }
165
166 if (pdev)
167 platform_set_drvdata(pdev, new);
168 else
169 list_add_tail(&new->list, &phram_list);
170
171 return 0;
172
173out2:
174 phram_unmap(new);
175out1:
176 kfree(new);
177out0:
178 return ret;
179}
180
181static int parse_num64(uint64_t *num64, char *token)
182{
183 size_t len;
184 int shift = 0;
185 int ret;
186
187 len = strlen(token);
188 /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
189 if (len > 2) {
190 if (token[len - 1] == 'i') {
191 switch (token[len - 2]) {
192 case 'G':
193 shift += 10;
194 fallthrough;
195 case 'M':
196 shift += 10;
197 fallthrough;
198 case 'k':
199 shift += 10;
200 token[len - 2] = 0;
201 break;
202 default:
203 return -EINVAL;
204 }
205 }
206 }
207
208 ret = kstrtou64(token, 0, num64);
209 *num64 <<= shift;
210
211 return ret;
212}
213
214static int parse_name(char **pname, const char *token)
215{
216 size_t len;
217 char *name;
218
219 len = strlen(token) + 1;
220 if (len > 64)
221 return -ENOSPC;
222
223 name = kstrdup(token, GFP_KERNEL);
224 if (!name)
225 return -ENOMEM;
226
227 *pname = name;
228 return 0;
229}
230
231
232static inline void kill_final_newline(char *str)
233{
234 char *newline = strrchr(str, '\n');
235
236 if (newline && !newline[1])
237 *newline = 0;
238}
239
240
241#define parse_err(fmt, args...) do { \
242 pr_err(fmt , ## args); \
243 return 1; \
244} while (0)
245
246#ifndef MODULE
247static int phram_init_called;
248/*
249 * This shall contain the module parameter if any. It is of the form:
250 * - phram=<device>,<address>,<size>[,<erasesize>] for module case
251 * - phram.phram=<device>,<address>,<size>[,<erasesize>] for built-in case
252 * We leave 64 bytes for the device name, 20 for the address , 20 for the
253 * size and 20 for the erasesize.
254 * Example: phram.phram=rootfs,0xa0000000,512Mi,65536
255 */
256static char phram_paramline[64 + 20 + 20 + 20];
257#endif
258
259static int phram_setup(const char *val)
260{
261 char buf[64 + 20 + 20 + 20], *str = buf;
262 char *token[4];
263 char *name;
264 uint64_t start;
265 uint64_t len;
266 uint64_t erasesize = PAGE_SIZE;
267 uint32_t rem;
268 int i, ret;
269
270 if (strnlen(val, sizeof(buf)) >= sizeof(buf))
271 parse_err("parameter too long\n");
272
273 strcpy(str, val);
274 kill_final_newline(str);
275
276 for (i = 0; i < 4; i++)
277 token[i] = strsep(&str, ",");
278
279 if (str)
280 parse_err("too many arguments\n");
281
282 if (!token[2])
283 parse_err("not enough arguments\n");
284
285 ret = parse_name(&name, token[0]);
286 if (ret)
287 return ret;
288
289 ret = parse_num64(&start, token[1]);
290 if (ret) {
291 parse_err("illegal start address\n");
292 goto error;
293 }
294
295 ret = parse_num64(&len, token[2]);
296 if (ret) {
297 parse_err("illegal device length\n");
298 goto error;
299 }
300
301 if (token[3]) {
302 ret = parse_num64(&erasesize, token[3]);
303 if (ret) {
304 parse_err("illegal erasesize\n");
305 goto error;
306 }
307 }
308
309 if (len == 0 || erasesize == 0 || erasesize > len
310 || erasesize > UINT_MAX) {
311 parse_err("illegal erasesize or len\n");
312 ret = -EINVAL;
313 goto error;
314 }
315
316 div_u64_rem(len, (uint32_t)erasesize, &rem);
317 if (rem) {
318 parse_err("len is not multiple of erasesize\n");
319 ret = -EINVAL;
320 goto error;
321 }
322
323 ret = register_device(NULL, name, start, len, (uint32_t)erasesize);
324 if (ret)
325 goto error;
326
327 pr_info("%s device: %#llx at %#llx for erasesize %#llx\n", name, len, start, erasesize);
328 return 0;
329
330error:
331 kfree(name);
332 return ret;
333}
334
335static int phram_param_call(const char *val, const struct kernel_param *kp)
336{
337#ifdef MODULE
338 return phram_setup(val);
339#else
340 /*
341 * If more parameters are later passed in via
342 * /sys/module/phram/parameters/phram
343 * and init_phram() has already been called,
344 * we can parse the argument now.
345 */
346
347 if (phram_init_called)
348 return phram_setup(val);
349
350 /*
351 * During early boot stage, we only save the parameters
352 * here. We must parse them later: if the param passed
353 * from kernel boot command line, phram_param_call() is
354 * called so early that it is not possible to resolve
355 * the device (even kmalloc() fails). Defer that work to
356 * phram_setup().
357 */
358
359 if (strlen(val) >= sizeof(phram_paramline))
360 return -ENOSPC;
361 strcpy(phram_paramline, val);
362
363 return 0;
364#endif
365}
366
367module_param_call(phram, phram_param_call, NULL, NULL, 0200);
368MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>[,<erasesize>]\"");
369
370#ifdef CONFIG_OF
371static const struct of_device_id phram_of_match[] = {
372 { .compatible = "phram" },
373 {}
374};
375MODULE_DEVICE_TABLE(of, phram_of_match);
376#endif
377
378static int phram_probe(struct platform_device *pdev)
379{
380 struct resource *res;
381
382 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
383 if (!res)
384 return -ENOMEM;
385
386 /* mtd_set_of_node() reads name from "label" */
387 return register_device(pdev, NULL, res->start, resource_size(res),
388 PAGE_SIZE);
389}
390
391static void phram_remove(struct platform_device *pdev)
392{
393 struct phram_mtd_list *phram = platform_get_drvdata(pdev);
394
395 mtd_device_unregister(&phram->mtd);
396 phram_unmap(phram);
397 kfree(phram);
398}
399
400static struct platform_driver phram_driver = {
401 .probe = phram_probe,
402 .remove_new = phram_remove,
403 .driver = {
404 .name = "phram",
405 .of_match_table = of_match_ptr(phram_of_match),
406 },
407};
408
409static int __init init_phram(void)
410{
411 int ret;
412
413 ret = platform_driver_register(&phram_driver);
414 if (ret)
415 return ret;
416
417#ifndef MODULE
418 if (phram_paramline[0])
419 ret = phram_setup(phram_paramline);
420 phram_init_called = 1;
421#endif
422
423 if (ret)
424 platform_driver_unregister(&phram_driver);
425
426 return ret;
427}
428
429static void __exit cleanup_phram(void)
430{
431 unregister_devices();
432 platform_driver_unregister(&phram_driver);
433}
434
435module_init(init_phram);
436module_exit(cleanup_phram);
437
438MODULE_LICENSE("GPL");
439MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
440MODULE_DESCRIPTION("MTD driver for physical RAM");
1/**
2 * Copyright (c) ???? Jochen Schäuble <psionic@psionic.de>
3 * Copyright (c) 2003-2004 Joern Engel <joern@wh.fh-wedel.de>
4 *
5 * Usage:
6 *
7 * one commend line parameter per device, each in the form:
8 * phram=<name>,<start>,<len>
9 * <name> may be up to 63 characters.
10 * <start> and <len> can be octal, decimal or hexadecimal. If followed
11 * by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
12 * gigabytes.
13 *
14 * Example:
15 * phram=swap,64Mi,128Mi phram=test,900Mi,1Mi
16 */
17
18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
20#include <asm/io.h>
21#include <linux/init.h>
22#include <linux/kernel.h>
23#include <linux/list.h>
24#include <linux/module.h>
25#include <linux/moduleparam.h>
26#include <linux/slab.h>
27#include <linux/mtd/mtd.h>
28
29struct phram_mtd_list {
30 struct mtd_info mtd;
31 struct list_head list;
32};
33
34static LIST_HEAD(phram_list);
35
36
37static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
38{
39 u_char *start = mtd->priv;
40
41 if (instr->addr + instr->len > mtd->size)
42 return -EINVAL;
43
44 memset(start + instr->addr, 0xff, instr->len);
45
46 /* This'll catch a few races. Free the thing before returning :)
47 * I don't feel at all ashamed. This kind of thing is possible anyway
48 * with flash, but unlikely.
49 */
50
51 instr->state = MTD_ERASE_DONE;
52
53 mtd_erase_callback(instr);
54
55 return 0;
56}
57
58static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
59 size_t *retlen, void **virt, resource_size_t *phys)
60{
61 if (from + len > mtd->size)
62 return -EINVAL;
63
64 /* can we return a physical address with this driver? */
65 if (phys)
66 return -EINVAL;
67
68 *virt = mtd->priv + from;
69 *retlen = len;
70 return 0;
71}
72
73static void phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
74{
75}
76
77static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
78 size_t *retlen, u_char *buf)
79{
80 u_char *start = mtd->priv;
81
82 if (from >= mtd->size)
83 return -EINVAL;
84
85 if (len > mtd->size - from)
86 len = mtd->size - from;
87
88 memcpy(buf, start + from, len);
89
90 *retlen = len;
91 return 0;
92}
93
94static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
95 size_t *retlen, const u_char *buf)
96{
97 u_char *start = mtd->priv;
98
99 if (to >= mtd->size)
100 return -EINVAL;
101
102 if (len > mtd->size - to)
103 len = mtd->size - to;
104
105 memcpy(start + to, buf, len);
106
107 *retlen = len;
108 return 0;
109}
110
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 iounmap(this->mtd.priv);
120 kfree(this->mtd.name);
121 kfree(this);
122 }
123}
124
125static int register_device(char *name, unsigned long start, unsigned long len)
126{
127 struct phram_mtd_list *new;
128 int ret = -ENOMEM;
129
130 new = kzalloc(sizeof(*new), GFP_KERNEL);
131 if (!new)
132 goto out0;
133
134 ret = -EIO;
135 new->mtd.priv = ioremap(start, len);
136 if (!new->mtd.priv) {
137 pr_err("ioremap failed\n");
138 goto out1;
139 }
140
141
142 new->mtd.name = name;
143 new->mtd.size = len;
144 new->mtd.flags = MTD_CAP_RAM;
145 new->mtd.erase = phram_erase;
146 new->mtd.point = phram_point;
147 new->mtd.unpoint = phram_unpoint;
148 new->mtd.read = phram_read;
149 new->mtd.write = phram_write;
150 new->mtd.owner = THIS_MODULE;
151 new->mtd.type = MTD_RAM;
152 new->mtd.erasesize = PAGE_SIZE;
153 new->mtd.writesize = 1;
154
155 ret = -EAGAIN;
156 if (mtd_device_register(&new->mtd, NULL, 0)) {
157 pr_err("Failed to register new device\n");
158 goto out2;
159 }
160
161 list_add_tail(&new->list, &phram_list);
162 return 0;
163
164out2:
165 iounmap(new->mtd.priv);
166out1:
167 kfree(new);
168out0:
169 return ret;
170}
171
172static int ustrtoul(const char *cp, char **endp, unsigned int base)
173{
174 unsigned long result = simple_strtoul(cp, endp, base);
175
176 switch (**endp) {
177 case 'G':
178 result *= 1024;
179 case 'M':
180 result *= 1024;
181 case 'k':
182 result *= 1024;
183 /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
184 if ((*endp)[1] == 'i')
185 (*endp) += 2;
186 }
187 return result;
188}
189
190static int parse_num32(uint32_t *num32, const char *token)
191{
192 char *endp;
193 unsigned long n;
194
195 n = ustrtoul(token, &endp, 0);
196 if (*endp)
197 return -EINVAL;
198
199 *num32 = n;
200 return 0;
201}
202
203static int parse_name(char **pname, const char *token)
204{
205 size_t len;
206 char *name;
207
208 len = strlen(token) + 1;
209 if (len > 64)
210 return -ENOSPC;
211
212 name = kmalloc(len, GFP_KERNEL);
213 if (!name)
214 return -ENOMEM;
215
216 strcpy(name, token);
217
218 *pname = name;
219 return 0;
220}
221
222
223static inline void kill_final_newline(char *str)
224{
225 char *newline = strrchr(str, '\n');
226 if (newline && !newline[1])
227 *newline = 0;
228}
229
230
231#define parse_err(fmt, args...) do { \
232 pr_err(fmt , ## args); \
233 return 1; \
234} while (0)
235
236static int phram_setup(const char *val, struct kernel_param *kp)
237{
238 char buf[64+12+12], *str = buf;
239 char *token[3];
240 char *name;
241 uint32_t start;
242 uint32_t len;
243 int i, ret;
244
245 if (strnlen(val, sizeof(buf)) >= sizeof(buf))
246 parse_err("parameter too long\n");
247
248 strcpy(str, val);
249 kill_final_newline(str);
250
251 for (i=0; i<3; i++)
252 token[i] = strsep(&str, ",");
253
254 if (str)
255 parse_err("too many arguments\n");
256
257 if (!token[2])
258 parse_err("not enough arguments\n");
259
260 ret = parse_name(&name, token[0]);
261 if (ret)
262 return ret;
263
264 ret = parse_num32(&start, token[1]);
265 if (ret) {
266 kfree(name);
267 parse_err("illegal start address\n");
268 }
269
270 ret = parse_num32(&len, token[2]);
271 if (ret) {
272 kfree(name);
273 parse_err("illegal device length\n");
274 }
275
276 ret = register_device(name, start, len);
277 if (!ret)
278 pr_info("%s device: %#x at %#x\n", name, len, start);
279 else
280 kfree(name);
281
282 return ret;
283}
284
285module_param_call(phram, phram_setup, NULL, NULL, 000);
286MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
287
288
289static int __init init_phram(void)
290{
291 return 0;
292}
293
294static void __exit cleanup_phram(void)
295{
296 unregister_devices();
297}
298
299module_init(init_phram);
300module_exit(cleanup_phram);
301
302MODULE_LICENSE("GPL");
303MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
304MODULE_DESCRIPTION("MTD driver for physical RAM");