1 /*
2 * c 2001 PPC 64 Team, IBM Corp
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * /dev/nvram driver for PPC64
10 *
11 * This perhaps should live in drivers/char
12 *
13 * TODO: Split the /dev/nvram part (that one can use
14 * drivers/char/generic_nvram.c) from the arch & partition
15 * parsing code.
16 */
17
18 #include <linux/module.h>
19
20 #include <linux/types.h>
21 #include <linux/errno.h>
22 #include <linux/fs.h>
23 #include <linux/miscdevice.h>
24 #include <linux/fcntl.h>
25 #include <linux/nvram.h>
26 #include <linux/init.h>
27 #include <linux/slab.h>
28 #include <linux/spinlock.h>
29 #include <asm/uaccess.h>
30 #include <asm/nvram.h>
31 #include <asm/rtas.h>
32 #include <asm/prom.h>
33 #include <asm/machdep.h>
34
35 #undef DEBUG_NVRAM
36
37 #define NVRAM_HEADER_LEN sizeof(struct nvram_header)
38 #define NVRAM_BLOCK_LEN NVRAM_HEADER_LEN
39
40 /* If change this size, then change the size of NVNAME_LEN */
41 struct nvram_header {
42 unsigned char signature;
43 unsigned char checksum;
44 unsigned short length;
45 /* Terminating null required only for names < 12 chars. */
46 char name[12];
47 };
48
49 struct nvram_partition {
50 struct list_head partition;
51 struct nvram_header header;
52 unsigned int index;
53 };
54
55 static LIST_HEAD(nvram_partitions);
56
dev_nvram_llseek(struct file * file,loff_t offset,int origin)57 static loff_t dev_nvram_llseek(struct file *file, loff_t offset, int origin)
58 {
59 int size;
60
61 if (ppc_md.nvram_size == NULL)
62 return -ENODEV;
63 size = ppc_md.nvram_size();
64
65 switch (origin) {
66 case 1:
67 offset += file->f_pos;
68 break;
69 case 2:
70 offset += size;
71 break;
72 }
73 if (offset < 0)
74 return -EINVAL;
75 file->f_pos = offset;
76 return file->f_pos;
77 }
78
79
dev_nvram_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)80 static ssize_t dev_nvram_read(struct file *file, char __user *buf,
81 size_t count, loff_t *ppos)
82 {
83 ssize_t ret;
84 char *tmp = NULL;
85 ssize_t size;
86
87 ret = -ENODEV;
88 if (!ppc_md.nvram_size)
89 goto out;
90
91 ret = 0;
92 size = ppc_md.nvram_size();
93 if (*ppos >= size || size < 0)
94 goto out;
95
96 count = min_t(size_t, count, size - *ppos);
97 count = min(count, PAGE_SIZE);
98
99 ret = -ENOMEM;
100 tmp = kmalloc(count, GFP_KERNEL);
101 if (!tmp)
102 goto out;
103
104 ret = ppc_md.nvram_read(tmp, count, ppos);
105 if (ret <= 0)
106 goto out;
107
108 if (copy_to_user(buf, tmp, ret))
109 ret = -EFAULT;
110
111 out:
112 kfree(tmp);
113 return ret;
114
115 }
116
dev_nvram_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)117 static ssize_t dev_nvram_write(struct file *file, const char __user *buf,
118 size_t count, loff_t *ppos)
119 {
120 ssize_t ret;
121 char *tmp = NULL;
122 ssize_t size;
123
124 ret = -ENODEV;
125 if (!ppc_md.nvram_size)
126 goto out;
127
128 ret = 0;
129 size = ppc_md.nvram_size();
130 if (*ppos >= size || size < 0)
131 goto out;
132
133 count = min_t(size_t, count, size - *ppos);
134 count = min(count, PAGE_SIZE);
135
136 ret = -ENOMEM;
137 tmp = kmalloc(count, GFP_KERNEL);
138 if (!tmp)
139 goto out;
140
141 ret = -EFAULT;
142 if (copy_from_user(tmp, buf, count))
143 goto out;
144
145 ret = ppc_md.nvram_write(tmp, count, ppos);
146
147 out:
148 kfree(tmp);
149 return ret;
150
151 }
152
dev_nvram_ioctl(struct file * file,unsigned int cmd,unsigned long arg)153 static long dev_nvram_ioctl(struct file *file, unsigned int cmd,
154 unsigned long arg)
155 {
156 switch(cmd) {
157 #ifdef CONFIG_PPC_PMAC
158 case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
159 printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
160 case IOC_NVRAM_GET_OFFSET: {
161 int part, offset;
162
163 if (!machine_is(powermac))
164 return -EINVAL;
165 if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
166 return -EFAULT;
167 if (part < pmac_nvram_OF || part > pmac_nvram_NR)
168 return -EINVAL;
169 offset = pmac_get_partition(part);
170 if (offset < 0)
171 return offset;
172 if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
173 return -EFAULT;
174 return 0;
175 }
176 #endif /* CONFIG_PPC_PMAC */
177 default:
178 return -EINVAL;
179 }
180 }
181
182 const struct file_operations nvram_fops = {
183 .owner = THIS_MODULE,
184 .llseek = dev_nvram_llseek,
185 .read = dev_nvram_read,
186 .write = dev_nvram_write,
187 .unlocked_ioctl = dev_nvram_ioctl,
188 };
189
190 static struct miscdevice nvram_dev = {
191 NVRAM_MINOR,
192 "nvram",
193 &nvram_fops
194 };
195
196
197 #ifdef DEBUG_NVRAM
nvram_print_partitions(char * label)198 static void __init nvram_print_partitions(char * label)
199 {
200 struct nvram_partition * tmp_part;
201
202 printk(KERN_WARNING "--------%s---------\n", label);
203 printk(KERN_WARNING "indx\t\tsig\tchks\tlen\tname\n");
204 list_for_each_entry(tmp_part, &nvram_partitions, partition) {
205 printk(KERN_WARNING "%4d \t%02x\t%02x\t%d\t%12s\n",
206 tmp_part->index, tmp_part->header.signature,
207 tmp_part->header.checksum, tmp_part->header.length,
208 tmp_part->header.name);
209 }
210 }
211 #endif
212
213
nvram_write_header(struct nvram_partition * part)214 static int __init nvram_write_header(struct nvram_partition * part)
215 {
216 loff_t tmp_index;
217 int rc;
218
219 tmp_index = part->index;
220 rc = ppc_md.nvram_write((char *)&part->header, NVRAM_HEADER_LEN, &tmp_index);
221
222 return rc;
223 }
224
225
nvram_checksum(struct nvram_header * p)226 static unsigned char __init nvram_checksum(struct nvram_header *p)
227 {
228 unsigned int c_sum, c_sum2;
229 unsigned short *sp = (unsigned short *)p->name; /* assume 6 shorts */
230 c_sum = p->signature + p->length + sp[0] + sp[1] + sp[2] + sp[3] + sp[4] + sp[5];
231
232 /* The sum may have spilled into the 3rd byte. Fold it back. */
233 c_sum = ((c_sum & 0xffff) + (c_sum >> 16)) & 0xffff;
234 /* The sum cannot exceed 2 bytes. Fold it into a checksum */
235 c_sum2 = (c_sum >> 8) + (c_sum << 8);
236 c_sum = ((c_sum + c_sum2) >> 8) & 0xff;
237 return c_sum;
238 }
239
240 /*
241 * Per the criteria passed via nvram_remove_partition(), should this
242 * partition be removed? 1=remove, 0=keep
243 */
nvram_can_remove_partition(struct nvram_partition * part,const char * name,int sig,const char * exceptions[])244 static int nvram_can_remove_partition(struct nvram_partition *part,
245 const char *name, int sig, const char *exceptions[])
246 {
247 if (part->header.signature != sig)
248 return 0;
249 if (name) {
250 if (strncmp(name, part->header.name, 12))
251 return 0;
252 } else if (exceptions) {
253 const char **except;
254 for (except = exceptions; *except; except++) {
255 if (!strncmp(*except, part->header.name, 12))
256 return 0;
257 }
258 }
259 return 1;
260 }
261
262 /**
263 * nvram_remove_partition - Remove one or more partitions in nvram
264 * @name: name of the partition to remove, or NULL for a
265 * signature only match
266 * @sig: signature of the partition(s) to remove
267 * @exceptions: When removing all partitions with a matching signature,
268 * leave these alone.
269 */
270
nvram_remove_partition(const char * name,int sig,const char * exceptions[])271 int __init nvram_remove_partition(const char *name, int sig,
272 const char *exceptions[])
273 {
274 struct nvram_partition *part, *prev, *tmp;
275 int rc;
276
277 list_for_each_entry(part, &nvram_partitions, partition) {
278 if (!nvram_can_remove_partition(part, name, sig, exceptions))
279 continue;
280
281 /* Make partition a free partition */
282 part->header.signature = NVRAM_SIG_FREE;
283 strncpy(part->header.name, "wwwwwwwwwwww", 12);
284 part->header.checksum = nvram_checksum(&part->header);
285 rc = nvram_write_header(part);
286 if (rc <= 0) {
287 printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
288 return rc;
289 }
290 }
291
292 /* Merge contiguous ones */
293 prev = NULL;
294 list_for_each_entry_safe(part, tmp, &nvram_partitions, partition) {
295 if (part->header.signature != NVRAM_SIG_FREE) {
296 prev = NULL;
297 continue;
298 }
299 if (prev) {
300 prev->header.length += part->header.length;
301 prev->header.checksum = nvram_checksum(&part->header);
302 rc = nvram_write_header(part);
303 if (rc <= 0) {
304 printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
305 return rc;
306 }
307 list_del(&part->partition);
308 kfree(part);
309 } else
310 prev = part;
311 }
312
313 return 0;
314 }
315
316 /**
317 * nvram_create_partition - Create a partition in nvram
318 * @name: name of the partition to create
319 * @sig: signature of the partition to create
320 * @req_size: size of data to allocate in bytes
321 * @min_size: minimum acceptable size (0 means req_size)
322 *
323 * Returns a negative error code or a positive nvram index
324 * of the beginning of the data area of the newly created
325 * partition. If you provided a min_size smaller than req_size
326 * you need to query for the actual size yourself after the
327 * call using nvram_partition_get_size().
328 */
nvram_create_partition(const char * name,int sig,int req_size,int min_size)329 loff_t __init nvram_create_partition(const char *name, int sig,
330 int req_size, int min_size)
331 {
332 struct nvram_partition *part;
333 struct nvram_partition *new_part;
334 struct nvram_partition *free_part = NULL;
335 static char nv_init_vals[16];
336 loff_t tmp_index;
337 long size = 0;
338 int rc;
339
340 /* Convert sizes from bytes to blocks */
341 req_size = _ALIGN_UP(req_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
342 min_size = _ALIGN_UP(min_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
343
344 /* If no minimum size specified, make it the same as the
345 * requested size
346 */
347 if (min_size == 0)
348 min_size = req_size;
349 if (min_size > req_size)
350 return -EINVAL;
351
352 /* Now add one block to each for the header */
353 req_size += 1;
354 min_size += 1;
355
356 /* Find a free partition that will give us the maximum needed size
357 If can't find one that will give us the minimum size needed */
358 list_for_each_entry(part, &nvram_partitions, partition) {
359 if (part->header.signature != NVRAM_SIG_FREE)
360 continue;
361
362 if (part->header.length >= req_size) {
363 size = req_size;
364 free_part = part;
365 break;
366 }
367 if (part->header.length > size &&
368 part->header.length >= min_size) {
369 size = part->header.length;
370 free_part = part;
371 }
372 }
373 if (!size)
374 return -ENOSPC;
375
376 /* Create our OS partition */
377 new_part = kmalloc(sizeof(*new_part), GFP_KERNEL);
378 if (!new_part) {
379 pr_err("nvram_create_os_partition: kmalloc failed\n");
380 return -ENOMEM;
381 }
382
383 new_part->index = free_part->index;
384 new_part->header.signature = sig;
385 new_part->header.length = size;
386 strncpy(new_part->header.name, name, 12);
387 new_part->header.checksum = nvram_checksum(&new_part->header);
388
389 rc = nvram_write_header(new_part);
390 if (rc <= 0) {
391 pr_err("nvram_create_os_partition: nvram_write_header "
392 "failed (%d)\n", rc);
393 return rc;
394 }
395 list_add_tail(&new_part->partition, &free_part->partition);
396
397 /* Adjust or remove the partition we stole the space from */
398 if (free_part->header.length > size) {
399 free_part->index += size * NVRAM_BLOCK_LEN;
400 free_part->header.length -= size;
401 free_part->header.checksum = nvram_checksum(&free_part->header);
402 rc = nvram_write_header(free_part);
403 if (rc <= 0) {
404 pr_err("nvram_create_os_partition: nvram_write_header "
405 "failed (%d)\n", rc);
406 return rc;
407 }
408 } else {
409 list_del(&free_part->partition);
410 kfree(free_part);
411 }
412
413 /* Clear the new partition */
414 for (tmp_index = new_part->index + NVRAM_HEADER_LEN;
415 tmp_index < ((size - 1) * NVRAM_BLOCK_LEN);
416 tmp_index += NVRAM_BLOCK_LEN) {
417 rc = ppc_md.nvram_write(nv_init_vals, NVRAM_BLOCK_LEN, &tmp_index);
418 if (rc <= 0) {
419 pr_err("nvram_create_partition: nvram_write failed (%d)\n", rc);
420 return rc;
421 }
422 }
423
424 return new_part->index + NVRAM_HEADER_LEN;
425 }
426
427 /**
428 * nvram_get_partition_size - Get the data size of an nvram partition
429 * @data_index: This is the offset of the start of the data of
430 * the partition. The same value that is returned by
431 * nvram_create_partition().
432 */
nvram_get_partition_size(loff_t data_index)433 int nvram_get_partition_size(loff_t data_index)
434 {
435 struct nvram_partition *part;
436
437 list_for_each_entry(part, &nvram_partitions, partition) {
438 if (part->index + NVRAM_HEADER_LEN == data_index)
439 return (part->header.length - 1) * NVRAM_BLOCK_LEN;
440 }
441 return -1;
442 }
443
444
445 /**
446 * nvram_find_partition - Find an nvram partition by signature and name
447 * @name: Name of the partition or NULL for any name
448 * @sig: Signature to test against
449 * @out_size: if non-NULL, returns the size of the data part of the partition
450 */
nvram_find_partition(const char * name,int sig,int * out_size)451 loff_t nvram_find_partition(const char *name, int sig, int *out_size)
452 {
453 struct nvram_partition *p;
454
455 list_for_each_entry(p, &nvram_partitions, partition) {
456 if (p->header.signature == sig &&
457 (!name || !strncmp(p->header.name, name, 12))) {
458 if (out_size)
459 *out_size = (p->header.length - 1) *
460 NVRAM_BLOCK_LEN;
461 return p->index + NVRAM_HEADER_LEN;
462 }
463 }
464 return 0;
465 }
466
nvram_scan_partitions(void)467 int __init nvram_scan_partitions(void)
468 {
469 loff_t cur_index = 0;
470 struct nvram_header phead;
471 struct nvram_partition * tmp_part;
472 unsigned char c_sum;
473 char * header;
474 int total_size;
475 int err;
476
477 if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
478 return -ENODEV;
479 total_size = ppc_md.nvram_size();
480
481 header = kmalloc(NVRAM_HEADER_LEN, GFP_KERNEL);
482 if (!header) {
483 printk(KERN_ERR "nvram_scan_partitions: Failed kmalloc\n");
484 return -ENOMEM;
485 }
486
487 while (cur_index < total_size) {
488
489 err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
490 if (err != NVRAM_HEADER_LEN) {
491 printk(KERN_ERR "nvram_scan_partitions: Error parsing "
492 "nvram partitions\n");
493 goto out;
494 }
495
496 cur_index -= NVRAM_HEADER_LEN; /* nvram_read will advance us */
497
498 memcpy(&phead, header, NVRAM_HEADER_LEN);
499
500 err = 0;
501 c_sum = nvram_checksum(&phead);
502 if (c_sum != phead.checksum) {
503 printk(KERN_WARNING "WARNING: nvram partition checksum"
504 " was %02x, should be %02x!\n",
505 phead.checksum, c_sum);
506 printk(KERN_WARNING "Terminating nvram partition scan\n");
507 goto out;
508 }
509 if (!phead.length) {
510 printk(KERN_WARNING "WARNING: nvram corruption "
511 "detected: 0-length partition\n");
512 goto out;
513 }
514 tmp_part = (struct nvram_partition *)
515 kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
516 err = -ENOMEM;
517 if (!tmp_part) {
518 printk(KERN_ERR "nvram_scan_partitions: kmalloc failed\n");
519 goto out;
520 }
521
522 memcpy(&tmp_part->header, &phead, NVRAM_HEADER_LEN);
523 tmp_part->index = cur_index;
524 list_add_tail(&tmp_part->partition, &nvram_partitions);
525
526 cur_index += phead.length * NVRAM_BLOCK_LEN;
527 }
528 err = 0;
529
530 #ifdef DEBUG_NVRAM
531 nvram_print_partitions("NVRAM Partitions");
532 #endif
533
534 out:
535 kfree(header);
536 return err;
537 }
538
nvram_init(void)539 static int __init nvram_init(void)
540 {
541 int rc;
542
543 BUILD_BUG_ON(NVRAM_BLOCK_LEN != 16);
544
545 if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
546 return -ENODEV;
547
548 rc = misc_register(&nvram_dev);
549 if (rc != 0) {
550 printk(KERN_ERR "nvram_init: failed to register device\n");
551 return rc;
552 }
553
554 return rc;
555 }
556
nvram_cleanup(void)557 void __exit nvram_cleanup(void)
558 {
559 misc_deregister( &nvram_dev );
560 }
561
562 module_init(nvram_init);
563 module_exit(nvram_cleanup);
564 MODULE_LICENSE("GPL");
565