xref: /linux/arch/powerpc/kernel/nvram_64.c (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
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 
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 
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 
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 
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
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 
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 
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  */
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 
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  */
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  */
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  */
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 
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 
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 
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