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 */
41struct 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
49struct nvram_partition {
50	struct list_head partition;
51	struct nvram_header header;
52	unsigned int index;
53};
54
55static LIST_HEAD(nvram_partitions);
56
57static 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
80static 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
119out:
120	kfree(tmp);
121	return ret;
122
123}
124
125static 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
155out:
156	kfree(tmp);
157	return ret;
158
159}
160
161static 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
190const 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
198static struct miscdevice nvram_dev = {
199	NVRAM_MINOR,
200	"nvram",
201	&nvram_fops
202};
203
204
205#ifdef DEBUG_NVRAM
206static 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
222static 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
238static 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 */
256static 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
283int __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 */
341loff_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 */
445int 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 */
463loff_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
479int __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
552static 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
570static void __exit nvram_cleanup(void)
571{
572        misc_deregister( &nvram_dev );
573}
574
575module_init(nvram_init);
576module_exit(nvram_cleanup);
577MODULE_LICENSE("GPL");
578