xref: /openbmc/linux/arch/powerpc/kernel/nvram_64.c (revision b34e08d5)
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 	if (!ppc_md.nvram_size) {
88 		ret = -ENODEV;
89 		goto out;
90 	}
91 
92 	size = ppc_md.nvram_size();
93 	if (size < 0) {
94 		ret = size;
95 		goto out;
96 	}
97 
98 	if (*ppos >= size) {
99 		ret = 0;
100 		goto out;
101 	}
102 
103 	count = min_t(size_t, count, size - *ppos);
104 	count = min(count, PAGE_SIZE);
105 
106 	tmp = kmalloc(count, GFP_KERNEL);
107 	if (!tmp) {
108 		ret = -ENOMEM;
109 		goto out;
110 	}
111 
112 	ret = ppc_md.nvram_read(tmp, count, ppos);
113 	if (ret <= 0)
114 		goto out;
115 
116 	if (copy_to_user(buf, tmp, ret))
117 		ret = -EFAULT;
118 
119 out:
120 	kfree(tmp);
121 	return ret;
122 
123 }
124 
125 static ssize_t dev_nvram_write(struct file *file, const char __user *buf,
126 			  size_t count, loff_t *ppos)
127 {
128 	ssize_t ret;
129 	char *tmp = NULL;
130 	ssize_t size;
131 
132 	ret = -ENODEV;
133 	if (!ppc_md.nvram_size)
134 		goto out;
135 
136 	ret = 0;
137 	size = ppc_md.nvram_size();
138 	if (*ppos >= size || size < 0)
139 		goto out;
140 
141 	count = min_t(size_t, count, size - *ppos);
142 	count = min(count, PAGE_SIZE);
143 
144 	ret = -ENOMEM;
145 	tmp = kmalloc(count, GFP_KERNEL);
146 	if (!tmp)
147 		goto out;
148 
149 	ret = -EFAULT;
150 	if (copy_from_user(tmp, buf, count))
151 		goto out;
152 
153 	ret = ppc_md.nvram_write(tmp, count, ppos);
154 
155 out:
156 	kfree(tmp);
157 	return ret;
158 
159 }
160 
161 static long dev_nvram_ioctl(struct file *file, unsigned int cmd,
162 			    unsigned long arg)
163 {
164 	switch(cmd) {
165 #ifdef CONFIG_PPC_PMAC
166 	case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
167 		printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
168 	case IOC_NVRAM_GET_OFFSET: {
169 		int part, offset;
170 
171 		if (!machine_is(powermac))
172 			return -EINVAL;
173 		if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
174 			return -EFAULT;
175 		if (part < pmac_nvram_OF || part > pmac_nvram_NR)
176 			return -EINVAL;
177 		offset = pmac_get_partition(part);
178 		if (offset < 0)
179 			return offset;
180 		if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
181 			return -EFAULT;
182 		return 0;
183 	}
184 #endif /* CONFIG_PPC_PMAC */
185 	default:
186 		return -EINVAL;
187 	}
188 }
189 
190 const struct file_operations nvram_fops = {
191 	.owner		= THIS_MODULE,
192 	.llseek		= dev_nvram_llseek,
193 	.read		= dev_nvram_read,
194 	.write		= dev_nvram_write,
195 	.unlocked_ioctl	= dev_nvram_ioctl,
196 };
197 
198 static struct miscdevice nvram_dev = {
199 	NVRAM_MINOR,
200 	"nvram",
201 	&nvram_fops
202 };
203 
204 
205 #ifdef DEBUG_NVRAM
206 static void __init nvram_print_partitions(char * label)
207 {
208 	struct nvram_partition * tmp_part;
209 
210 	printk(KERN_WARNING "--------%s---------\n", label);
211 	printk(KERN_WARNING "indx\t\tsig\tchks\tlen\tname\n");
212 	list_for_each_entry(tmp_part, &nvram_partitions, partition) {
213 		printk(KERN_WARNING "%4d    \t%02x\t%02x\t%d\t%12.12s\n",
214 		       tmp_part->index, tmp_part->header.signature,
215 		       tmp_part->header.checksum, tmp_part->header.length,
216 		       tmp_part->header.name);
217 	}
218 }
219 #endif
220 
221 
222 static int __init nvram_write_header(struct nvram_partition * part)
223 {
224 	loff_t tmp_index;
225 	int rc;
226 	struct nvram_header phead;
227 
228 	memcpy(&phead, &part->header, NVRAM_HEADER_LEN);
229 	phead.length = cpu_to_be16(phead.length);
230 
231 	tmp_index = part->index;
232 	rc = ppc_md.nvram_write((char *)&phead, NVRAM_HEADER_LEN, &tmp_index);
233 
234 	return rc;
235 }
236 
237 
238 static unsigned char __init nvram_checksum(struct nvram_header *p)
239 {
240 	unsigned int c_sum, c_sum2;
241 	unsigned short *sp = (unsigned short *)p->name; /* assume 6 shorts */
242 	c_sum = p->signature + p->length + sp[0] + sp[1] + sp[2] + sp[3] + sp[4] + sp[5];
243 
244 	/* The sum may have spilled into the 3rd byte.  Fold it back. */
245 	c_sum = ((c_sum & 0xffff) + (c_sum >> 16)) & 0xffff;
246 	/* The sum cannot exceed 2 bytes.  Fold it into a checksum */
247 	c_sum2 = (c_sum >> 8) + (c_sum << 8);
248 	c_sum = ((c_sum + c_sum2) >> 8) & 0xff;
249 	return c_sum;
250 }
251 
252 /*
253  * Per the criteria passed via nvram_remove_partition(), should this
254  * partition be removed?  1=remove, 0=keep
255  */
256 static int nvram_can_remove_partition(struct nvram_partition *part,
257 		const char *name, int sig, const char *exceptions[])
258 {
259 	if (part->header.signature != sig)
260 		return 0;
261 	if (name) {
262 		if (strncmp(name, part->header.name, 12))
263 			return 0;
264 	} else if (exceptions) {
265 		const char **except;
266 		for (except = exceptions; *except; except++) {
267 			if (!strncmp(*except, part->header.name, 12))
268 				return 0;
269 		}
270 	}
271 	return 1;
272 }
273 
274 /**
275  * nvram_remove_partition - Remove one or more partitions in nvram
276  * @name: name of the partition to remove, or NULL for a
277  *        signature only match
278  * @sig: signature of the partition(s) to remove
279  * @exceptions: When removing all partitions with a matching signature,
280  *        leave these alone.
281  */
282 
283 int __init nvram_remove_partition(const char *name, int sig,
284 						const char *exceptions[])
285 {
286 	struct nvram_partition *part, *prev, *tmp;
287 	int rc;
288 
289 	list_for_each_entry(part, &nvram_partitions, partition) {
290 		if (!nvram_can_remove_partition(part, name, sig, exceptions))
291 			continue;
292 
293 		/* Make partition a free partition */
294 		part->header.signature = NVRAM_SIG_FREE;
295 		strncpy(part->header.name, "wwwwwwwwwwww", 12);
296 		part->header.checksum = nvram_checksum(&part->header);
297 		rc = nvram_write_header(part);
298 		if (rc <= 0) {
299 			printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
300 			return rc;
301 		}
302 	}
303 
304 	/* Merge contiguous ones */
305 	prev = NULL;
306 	list_for_each_entry_safe(part, tmp, &nvram_partitions, partition) {
307 		if (part->header.signature != NVRAM_SIG_FREE) {
308 			prev = NULL;
309 			continue;
310 		}
311 		if (prev) {
312 			prev->header.length += part->header.length;
313 			prev->header.checksum = nvram_checksum(&part->header);
314 			rc = nvram_write_header(part);
315 			if (rc <= 0) {
316 				printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
317 				return rc;
318 			}
319 			list_del(&part->partition);
320 			kfree(part);
321 		} else
322 			prev = part;
323 	}
324 
325 	return 0;
326 }
327 
328 /**
329  * nvram_create_partition - Create a partition in nvram
330  * @name: name of the partition to create
331  * @sig: signature of the partition to create
332  * @req_size: size of data to allocate in bytes
333  * @min_size: minimum acceptable size (0 means req_size)
334  *
335  * Returns a negative error code or a positive nvram index
336  * of the beginning of the data area of the newly created
337  * partition. If you provided a min_size smaller than req_size
338  * you need to query for the actual size yourself after the
339  * call using nvram_partition_get_size().
340  */
341 loff_t __init nvram_create_partition(const char *name, int sig,
342 				     int req_size, int min_size)
343 {
344 	struct nvram_partition *part;
345 	struct nvram_partition *new_part;
346 	struct nvram_partition *free_part = NULL;
347 	static char nv_init_vals[16];
348 	loff_t tmp_index;
349 	long size = 0;
350 	int rc;
351 
352 	/* Convert sizes from bytes to blocks */
353 	req_size = _ALIGN_UP(req_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
354 	min_size = _ALIGN_UP(min_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
355 
356 	/* If no minimum size specified, make it the same as the
357 	 * requested size
358 	 */
359 	if (min_size == 0)
360 		min_size = req_size;
361 	if (min_size > req_size)
362 		return -EINVAL;
363 
364 	/* Now add one block to each for the header */
365 	req_size += 1;
366 	min_size += 1;
367 
368 	/* Find a free partition that will give us the maximum needed size
369 	   If can't find one that will give us the minimum size needed */
370 	list_for_each_entry(part, &nvram_partitions, partition) {
371 		if (part->header.signature != NVRAM_SIG_FREE)
372 			continue;
373 
374 		if (part->header.length >= req_size) {
375 			size = req_size;
376 			free_part = part;
377 			break;
378 		}
379 		if (part->header.length > size &&
380 		    part->header.length >= min_size) {
381 			size = part->header.length;
382 			free_part = part;
383 		}
384 	}
385 	if (!size)
386 		return -ENOSPC;
387 
388 	/* Create our OS partition */
389 	new_part = kmalloc(sizeof(*new_part), GFP_KERNEL);
390 	if (!new_part) {
391 		pr_err("nvram_create_os_partition: kmalloc failed\n");
392 		return -ENOMEM;
393 	}
394 
395 	new_part->index = free_part->index;
396 	new_part->header.signature = sig;
397 	new_part->header.length = size;
398 	strncpy(new_part->header.name, name, 12);
399 	new_part->header.checksum = nvram_checksum(&new_part->header);
400 
401 	rc = nvram_write_header(new_part);
402 	if (rc <= 0) {
403 		pr_err("nvram_create_os_partition: nvram_write_header "
404 		       "failed (%d)\n", rc);
405 		return rc;
406 	}
407 	list_add_tail(&new_part->partition, &free_part->partition);
408 
409 	/* Adjust or remove the partition we stole the space from */
410 	if (free_part->header.length > size) {
411 		free_part->index += size * NVRAM_BLOCK_LEN;
412 		free_part->header.length -= size;
413 		free_part->header.checksum = nvram_checksum(&free_part->header);
414 		rc = nvram_write_header(free_part);
415 		if (rc <= 0) {
416 			pr_err("nvram_create_os_partition: nvram_write_header "
417 			       "failed (%d)\n", rc);
418 			return rc;
419 		}
420 	} else {
421 		list_del(&free_part->partition);
422 		kfree(free_part);
423 	}
424 
425 	/* Clear the new partition */
426 	for (tmp_index = new_part->index + NVRAM_HEADER_LEN;
427 	     tmp_index <  ((size - 1) * NVRAM_BLOCK_LEN);
428 	     tmp_index += NVRAM_BLOCK_LEN) {
429 		rc = ppc_md.nvram_write(nv_init_vals, NVRAM_BLOCK_LEN, &tmp_index);
430 		if (rc <= 0) {
431 			pr_err("nvram_create_partition: nvram_write failed (%d)\n", rc);
432 			return rc;
433 		}
434 	}
435 
436 	return new_part->index + NVRAM_HEADER_LEN;
437 }
438 
439 /**
440  * nvram_get_partition_size - Get the data size of an nvram partition
441  * @data_index: This is the offset of the start of the data of
442  *              the partition. The same value that is returned by
443  *              nvram_create_partition().
444  */
445 int nvram_get_partition_size(loff_t data_index)
446 {
447 	struct nvram_partition *part;
448 
449 	list_for_each_entry(part, &nvram_partitions, partition) {
450 		if (part->index + NVRAM_HEADER_LEN == data_index)
451 			return (part->header.length - 1) * NVRAM_BLOCK_LEN;
452 	}
453 	return -1;
454 }
455 
456 
457 /**
458  * nvram_find_partition - Find an nvram partition by signature and name
459  * @name: Name of the partition or NULL for any name
460  * @sig: Signature to test against
461  * @out_size: if non-NULL, returns the size of the data part of the partition
462  */
463 loff_t nvram_find_partition(const char *name, int sig, int *out_size)
464 {
465 	struct nvram_partition *p;
466 
467 	list_for_each_entry(p, &nvram_partitions, partition) {
468 		if (p->header.signature == sig &&
469 		    (!name || !strncmp(p->header.name, name, 12))) {
470 			if (out_size)
471 				*out_size = (p->header.length - 1) *
472 					NVRAM_BLOCK_LEN;
473 			return p->index + NVRAM_HEADER_LEN;
474 		}
475 	}
476 	return 0;
477 }
478 
479 int __init nvram_scan_partitions(void)
480 {
481 	loff_t cur_index = 0;
482 	struct nvram_header phead;
483 	struct nvram_partition * tmp_part;
484 	unsigned char c_sum;
485 	char * header;
486 	int total_size;
487 	int err;
488 
489 	if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
490 		return -ENODEV;
491 	total_size = ppc_md.nvram_size();
492 
493 	header = kmalloc(NVRAM_HEADER_LEN, GFP_KERNEL);
494 	if (!header) {
495 		printk(KERN_ERR "nvram_scan_partitions: Failed kmalloc\n");
496 		return -ENOMEM;
497 	}
498 
499 	while (cur_index < total_size) {
500 
501 		err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
502 		if (err != NVRAM_HEADER_LEN) {
503 			printk(KERN_ERR "nvram_scan_partitions: Error parsing "
504 			       "nvram partitions\n");
505 			goto out;
506 		}
507 
508 		cur_index -= NVRAM_HEADER_LEN; /* nvram_read will advance us */
509 
510 		memcpy(&phead, header, NVRAM_HEADER_LEN);
511 
512 		phead.length = be16_to_cpu(phead.length);
513 
514 		err = 0;
515 		c_sum = nvram_checksum(&phead);
516 		if (c_sum != phead.checksum) {
517 			printk(KERN_WARNING "WARNING: nvram partition checksum"
518 			       " was %02x, should be %02x!\n",
519 			       phead.checksum, c_sum);
520 			printk(KERN_WARNING "Terminating nvram partition scan\n");
521 			goto out;
522 		}
523 		if (!phead.length) {
524 			printk(KERN_WARNING "WARNING: nvram corruption "
525 			       "detected: 0-length partition\n");
526 			goto out;
527 		}
528 		tmp_part = kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
529 		err = -ENOMEM;
530 		if (!tmp_part) {
531 			printk(KERN_ERR "nvram_scan_partitions: kmalloc failed\n");
532 			goto out;
533 		}
534 
535 		memcpy(&tmp_part->header, &phead, NVRAM_HEADER_LEN);
536 		tmp_part->index = cur_index;
537 		list_add_tail(&tmp_part->partition, &nvram_partitions);
538 
539 		cur_index += phead.length * NVRAM_BLOCK_LEN;
540 	}
541 	err = 0;
542 
543 #ifdef DEBUG_NVRAM
544 	nvram_print_partitions("NVRAM Partitions");
545 #endif
546 
547  out:
548 	kfree(header);
549 	return err;
550 }
551 
552 static int __init nvram_init(void)
553 {
554 	int rc;
555 
556 	BUILD_BUG_ON(NVRAM_BLOCK_LEN != 16);
557 
558 	if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
559 		return  -ENODEV;
560 
561   	rc = misc_register(&nvram_dev);
562 	if (rc != 0) {
563 		printk(KERN_ERR "nvram_init: failed to register device\n");
564 		return rc;
565 	}
566 
567   	return rc;
568 }
569 
570 void __exit nvram_cleanup(void)
571 {
572         misc_deregister( &nvram_dev );
573 }
574 
575 module_init(nvram_init);
576 module_exit(nvram_cleanup);
577 MODULE_LICENSE("GPL");
578