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
37static int nvram_scan_partitions(void);
38static int nvram_setup_partition(void);
39static int nvram_create_os_partition(void);
40static int nvram_remove_os_partition(void);
41
42static struct nvram_partition * nvram_part;
43static long nvram_error_log_index = -1;
44static long nvram_error_log_size = 0;
45
46int no_logging = 1; 	/* Until we initialize everything,
47			 * make sure we don't try logging
48			 * anything */
49
50extern volatile int error_log_cnt;
51
52struct err_log_info {
53	int error_type;
54	unsigned int seq_num;
55};
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	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
111out:
112	kfree(tmp);
113	return ret;
114
115}
116
117static 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
147out:
148	kfree(tmp);
149	return ret;
150
151}
152
153static int dev_nvram_ioctl(struct inode *inode, struct file *file,
154	unsigned int cmd, 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
182const 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	.ioctl =	dev_nvram_ioctl,
188};
189
190static struct miscdevice nvram_dev = {
191	NVRAM_MINOR,
192	"nvram",
193	&nvram_fops
194};
195
196
197#ifdef DEBUG_NVRAM
198static void nvram_print_partitions(char * label)
199{
200	struct list_head * p;
201	struct nvram_partition * tmp_part;
202
203	printk(KERN_WARNING "--------%s---------\n", label);
204	printk(KERN_WARNING "indx\t\tsig\tchks\tlen\tname\n");
205	list_for_each(p, &nvram_part->partition) {
206		tmp_part = list_entry(p, struct nvram_partition, partition);
207		printk(KERN_WARNING "%4d    \t%02x\t%02x\t%d\t%s\n",
208		       tmp_part->index, tmp_part->header.signature,
209		       tmp_part->header.checksum, tmp_part->header.length,
210		       tmp_part->header.name);
211	}
212}
213#endif
214
215
216static int nvram_write_header(struct nvram_partition * part)
217{
218	loff_t tmp_index;
219	int rc;
220
221	tmp_index = part->index;
222	rc = ppc_md.nvram_write((char *)&part->header, NVRAM_HEADER_LEN, &tmp_index);
223
224	return rc;
225}
226
227
228static unsigned char nvram_checksum(struct nvram_header *p)
229{
230	unsigned int c_sum, c_sum2;
231	unsigned short *sp = (unsigned short *)p->name; /* assume 6 shorts */
232	c_sum = p->signature + p->length + sp[0] + sp[1] + sp[2] + sp[3] + sp[4] + sp[5];
233
234	/* The sum may have spilled into the 3rd byte.  Fold it back. */
235	c_sum = ((c_sum & 0xffff) + (c_sum >> 16)) & 0xffff;
236	/* The sum cannot exceed 2 bytes.  Fold it into a checksum */
237	c_sum2 = (c_sum >> 8) + (c_sum << 8);
238	c_sum = ((c_sum + c_sum2) >> 8) & 0xff;
239	return c_sum;
240}
241
242
243/*
244 * Find an nvram partition, sig can be 0 for any
245 * partition or name can be NULL for any name, else
246 * tries to match both
247 */
248struct nvram_partition *nvram_find_partition(int sig, const char *name)
249{
250	struct nvram_partition * part;
251	struct list_head * p;
252
253	list_for_each(p, &nvram_part->partition) {
254		part = list_entry(p, struct nvram_partition, partition);
255
256		if (sig && part->header.signature != sig)
257			continue;
258		if (name && 0 != strncmp(name, part->header.name, 12))
259			continue;
260		return part;
261	}
262	return NULL;
263}
264EXPORT_SYMBOL(nvram_find_partition);
265
266
267static int nvram_remove_os_partition(void)
268{
269	struct list_head *i;
270	struct list_head *j;
271	struct nvram_partition * part;
272	struct nvram_partition * cur_part;
273	int rc;
274
275	list_for_each(i, &nvram_part->partition) {
276		part = list_entry(i, struct nvram_partition, partition);
277		if (part->header.signature != NVRAM_SIG_OS)
278			continue;
279
280		/* Make os partition a free partition */
281		part->header.signature = NVRAM_SIG_FREE;
282		sprintf(part->header.name, "wwwwwwwwwwww");
283		part->header.checksum = nvram_checksum(&part->header);
284
285		/* Merge contiguous free partitions backwards */
286		list_for_each_prev(j, &part->partition) {
287			cur_part = list_entry(j, struct nvram_partition, partition);
288			if (cur_part == nvram_part || cur_part->header.signature != NVRAM_SIG_FREE) {
289				break;
290			}
291
292			part->header.length += cur_part->header.length;
293			part->header.checksum = nvram_checksum(&part->header);
294			part->index = cur_part->index;
295
296			list_del(&cur_part->partition);
297			kfree(cur_part);
298			j = &part->partition; /* fixup our loop */
299		}
300
301		/* Merge contiguous free partitions forwards */
302		list_for_each(j, &part->partition) {
303			cur_part = list_entry(j, struct nvram_partition, partition);
304			if (cur_part == nvram_part || cur_part->header.signature != NVRAM_SIG_FREE) {
305				break;
306			}
307
308			part->header.length += cur_part->header.length;
309			part->header.checksum = nvram_checksum(&part->header);
310
311			list_del(&cur_part->partition);
312			kfree(cur_part);
313			j = &part->partition; /* fixup our loop */
314		}
315
316		rc = nvram_write_header(part);
317		if (rc <= 0) {
318			printk(KERN_ERR "nvram_remove_os_partition: nvram_write failed (%d)\n", rc);
319			return rc;
320		}
321
322	}
323
324	return 0;
325}
326
327/* nvram_create_os_partition
328 *
329 * Create a OS linux partition to buffer error logs.
330 * Will create a partition starting at the first free
331 * space found if space has enough room.
332 */
333static int nvram_create_os_partition(void)
334{
335	struct nvram_partition *part;
336	struct nvram_partition *new_part;
337	struct nvram_partition *free_part = NULL;
338	int seq_init[2] = { 0, 0 };
339	loff_t tmp_index;
340	long size = 0;
341	int rc;
342
343	/* Find a free partition that will give us the maximum needed size
344	   If can't find one that will give us the minimum size needed */
345	list_for_each_entry(part, &nvram_part->partition, partition) {
346		if (part->header.signature != NVRAM_SIG_FREE)
347			continue;
348
349		if (part->header.length >= NVRAM_MAX_REQ) {
350			size = NVRAM_MAX_REQ;
351			free_part = part;
352			break;
353		}
354		if (!size && part->header.length >= NVRAM_MIN_REQ) {
355			size = NVRAM_MIN_REQ;
356			free_part = part;
357		}
358	}
359	if (!size)
360		return -ENOSPC;
361
362	/* Create our OS partition */
363	new_part = kmalloc(sizeof(*new_part), GFP_KERNEL);
364	if (!new_part) {
365		printk(KERN_ERR "nvram_create_os_partition: kmalloc failed\n");
366		return -ENOMEM;
367	}
368
369	new_part->index = free_part->index;
370	new_part->header.signature = NVRAM_SIG_OS;
371	new_part->header.length = size;
372	strcpy(new_part->header.name, "ppc64,linux");
373	new_part->header.checksum = nvram_checksum(&new_part->header);
374
375	rc = nvram_write_header(new_part);
376	if (rc <= 0) {
377		printk(KERN_ERR "nvram_create_os_partition: nvram_write_header \
378				failed (%d)\n", rc);
379		return rc;
380	}
381
382	/* make sure and initialize to zero the sequence number and the error
383	   type logged */
384	tmp_index = new_part->index + NVRAM_HEADER_LEN;
385	rc = ppc_md.nvram_write((char *)&seq_init, sizeof(seq_init), &tmp_index);
386	if (rc <= 0) {
387		printk(KERN_ERR "nvram_create_os_partition: nvram_write "
388				"failed (%d)\n", rc);
389		return rc;
390	}
391
392	nvram_error_log_index = new_part->index + NVRAM_HEADER_LEN;
393	nvram_error_log_size = ((part->header.length - 1) *
394				NVRAM_BLOCK_LEN) - sizeof(struct err_log_info);
395
396	list_add_tail(&new_part->partition, &free_part->partition);
397
398	if (free_part->header.length <= size) {
399		list_del(&free_part->partition);
400		kfree(free_part);
401		return 0;
402	}
403
404	/* Adjust the partition we stole the space from */
405	free_part->index += size * NVRAM_BLOCK_LEN;
406	free_part->header.length -= size;
407	free_part->header.checksum = nvram_checksum(&free_part->header);
408
409	rc = nvram_write_header(free_part);
410	if (rc <= 0) {
411		printk(KERN_ERR "nvram_create_os_partition: nvram_write_header "
412		       "failed (%d)\n", rc);
413		return rc;
414	}
415
416	return 0;
417}
418
419
420/* nvram_setup_partition
421 *
422 * This will setup the partition we need for buffering the
423 * error logs and cleanup partitions if needed.
424 *
425 * The general strategy is the following:
426 * 1.) If there is ppc64,linux partition large enough then use it.
427 * 2.) If there is not a ppc64,linux partition large enough, search
428 * for a free partition that is large enough.
429 * 3.) If there is not a free partition large enough remove
430 * _all_ OS partitions and consolidate the space.
431 * 4.) Will first try getting a chunk that will satisfy the maximum
432 * error log size (NVRAM_MAX_REQ).
433 * 5.) If the max chunk cannot be allocated then try finding a chunk
434 * that will satisfy the minum needed (NVRAM_MIN_REQ).
435 */
436static int nvram_setup_partition(void)
437{
438	struct list_head * p;
439	struct nvram_partition * part;
440	int rc;
441
442	/* For now, we don't do any of this on pmac, until I
443	 * have figured out if it's worth killing some unused stuffs
444	 * in our nvram, as Apple defined partitions use pretty much
445	 * all of the space
446	 */
447	if (machine_is(powermac))
448		return -ENOSPC;
449
450	/* see if we have an OS partition that meets our needs.
451	   will try getting the max we need.  If not we'll delete
452	   partitions and try again. */
453	list_for_each(p, &nvram_part->partition) {
454		part = list_entry(p, struct nvram_partition, partition);
455		if (part->header.signature != NVRAM_SIG_OS)
456			continue;
457
458		if (strcmp(part->header.name, "ppc64,linux"))
459			continue;
460
461		if (part->header.length >= NVRAM_MIN_REQ) {
462			/* found our partition */
463			nvram_error_log_index = part->index + NVRAM_HEADER_LEN;
464			nvram_error_log_size = ((part->header.length - 1) *
465						NVRAM_BLOCK_LEN) - sizeof(struct err_log_info);
466			return 0;
467		}
468	}
469
470	/* try creating a partition with the free space we have */
471	rc = nvram_create_os_partition();
472	if (!rc) {
473		return 0;
474	}
475
476	/* need to free up some space */
477	rc = nvram_remove_os_partition();
478	if (rc) {
479		return rc;
480	}
481
482	/* create a partition in this new space */
483	rc = nvram_create_os_partition();
484	if (rc) {
485		printk(KERN_ERR "nvram_create_os_partition: Could not find a "
486		       "NVRAM partition large enough\n");
487		return rc;
488	}
489
490	return 0;
491}
492
493
494static int nvram_scan_partitions(void)
495{
496	loff_t cur_index = 0;
497	struct nvram_header phead;
498	struct nvram_partition * tmp_part;
499	unsigned char c_sum;
500	char * header;
501	int total_size;
502	int err;
503
504	if (ppc_md.nvram_size == NULL)
505		return -ENODEV;
506	total_size = ppc_md.nvram_size();
507
508	header = kmalloc(NVRAM_HEADER_LEN, GFP_KERNEL);
509	if (!header) {
510		printk(KERN_ERR "nvram_scan_partitions: Failed kmalloc\n");
511		return -ENOMEM;
512	}
513
514	while (cur_index < total_size) {
515
516		err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
517		if (err != NVRAM_HEADER_LEN) {
518			printk(KERN_ERR "nvram_scan_partitions: Error parsing "
519			       "nvram partitions\n");
520			goto out;
521		}
522
523		cur_index -= NVRAM_HEADER_LEN; /* nvram_read will advance us */
524
525		memcpy(&phead, header, NVRAM_HEADER_LEN);
526
527		err = 0;
528		c_sum = nvram_checksum(&phead);
529		if (c_sum != phead.checksum) {
530			printk(KERN_WARNING "WARNING: nvram partition checksum"
531			       " was %02x, should be %02x!\n",
532			       phead.checksum, c_sum);
533			printk(KERN_WARNING "Terminating nvram partition scan\n");
534			goto out;
535		}
536		if (!phead.length) {
537			printk(KERN_WARNING "WARNING: nvram corruption "
538			       "detected: 0-length partition\n");
539			goto out;
540		}
541		tmp_part = (struct nvram_partition *)
542			kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
543		err = -ENOMEM;
544		if (!tmp_part) {
545			printk(KERN_ERR "nvram_scan_partitions: kmalloc failed\n");
546			goto out;
547		}
548
549		memcpy(&tmp_part->header, &phead, NVRAM_HEADER_LEN);
550		tmp_part->index = cur_index;
551		list_add_tail(&tmp_part->partition, &nvram_part->partition);
552
553		cur_index += phead.length * NVRAM_BLOCK_LEN;
554	}
555	err = 0;
556
557 out:
558	kfree(header);
559	return err;
560}
561
562static int __init nvram_init(void)
563{
564	int error;
565	int rc;
566
567	if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
568		return  -ENODEV;
569
570  	rc = misc_register(&nvram_dev);
571	if (rc != 0) {
572		printk(KERN_ERR "nvram_init: failed to register device\n");
573		return rc;
574	}
575
576  	/* initialize our anchor for the nvram partition list */
577  	nvram_part = kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
578  	if (!nvram_part) {
579  		printk(KERN_ERR "nvram_init: Failed kmalloc\n");
580  		return -ENOMEM;
581  	}
582  	INIT_LIST_HEAD(&nvram_part->partition);
583
584  	/* Get all the NVRAM partitions */
585  	error = nvram_scan_partitions();
586  	if (error) {
587  		printk(KERN_ERR "nvram_init: Failed nvram_scan_partitions\n");
588  		return error;
589  	}
590
591  	if(nvram_setup_partition())
592  		printk(KERN_WARNING "nvram_init: Could not find nvram partition"
593  		       " for nvram buffered error logging.\n");
594
595#ifdef DEBUG_NVRAM
596	nvram_print_partitions("NVRAM Partitions");
597#endif
598
599  	return rc;
600}
601
602void __exit nvram_cleanup(void)
603{
604        misc_deregister( &nvram_dev );
605}
606
607
608#ifdef CONFIG_PPC_PSERIES
609
610/* nvram_write_error_log
611 *
612 * We need to buffer the error logs into nvram to ensure that we have
613 * the failure information to decode.  If we have a severe error there
614 * is no way to guarantee that the OS or the machine is in a state to
615 * get back to user land and write the error to disk.  For example if
616 * the SCSI device driver causes a Machine Check by writing to a bad
617 * IO address, there is no way of guaranteeing that the device driver
618 * is in any state that is would also be able to write the error data
619 * captured to disk, thus we buffer it in NVRAM for analysis on the
620 * next boot.
621 *
622 * In NVRAM the partition containing the error log buffer will looks like:
623 * Header (in bytes):
624 * +-----------+----------+--------+------------+------------------+
625 * | signature | checksum | length | name       | data             |
626 * |0          |1         |2      3|4         15|16        length-1|
627 * +-----------+----------+--------+------------+------------------+
628 *
629 * The 'data' section would look like (in bytes):
630 * +--------------+------------+-----------------------------------+
631 * | event_logged | sequence # | error log                         |
632 * |0            3|4          7|8            nvram_error_log_size-1|
633 * +--------------+------------+-----------------------------------+
634 *
635 * event_logged: 0 if event has not been logged to syslog, 1 if it has
636 * sequence #: The unique sequence # for each event. (until it wraps)
637 * error log: The error log from event_scan
638 */
639int nvram_write_error_log(char * buff, int length, unsigned int err_type)
640{
641	int rc;
642	loff_t tmp_index;
643	struct err_log_info info;
644
645	if (no_logging) {
646		return -EPERM;
647	}
648
649	if (nvram_error_log_index == -1) {
650		return -ESPIPE;
651	}
652
653	if (length > nvram_error_log_size) {
654		length = nvram_error_log_size;
655	}
656
657	info.error_type = err_type;
658	info.seq_num = error_log_cnt;
659
660	tmp_index = nvram_error_log_index;
661
662	rc = ppc_md.nvram_write((char *)&info, sizeof(struct err_log_info), &tmp_index);
663	if (rc <= 0) {
664		printk(KERN_ERR "nvram_write_error_log: Failed nvram_write (%d)\n", rc);
665		return rc;
666	}
667
668	rc = ppc_md.nvram_write(buff, length, &tmp_index);
669	if (rc <= 0) {
670		printk(KERN_ERR "nvram_write_error_log: Failed nvram_write (%d)\n", rc);
671		return rc;
672	}
673
674	return 0;
675}
676
677/* nvram_read_error_log
678 *
679 * Reads nvram for error log for at most 'length'
680 */
681int nvram_read_error_log(char * buff, int length, unsigned int * err_type)
682{
683	int rc;
684	loff_t tmp_index;
685	struct err_log_info info;
686
687	if (nvram_error_log_index == -1)
688		return -1;
689
690	if (length > nvram_error_log_size)
691		length = nvram_error_log_size;
692
693	tmp_index = nvram_error_log_index;
694
695	rc = ppc_md.nvram_read((char *)&info, sizeof(struct err_log_info), &tmp_index);
696	if (rc <= 0) {
697		printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
698		return rc;
699	}
700
701	rc = ppc_md.nvram_read(buff, length, &tmp_index);
702	if (rc <= 0) {
703		printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
704		return rc;
705	}
706
707	error_log_cnt = info.seq_num;
708	*err_type = info.error_type;
709
710	return 0;
711}
712
713/* This doesn't actually zero anything, but it sets the event_logged
714 * word to tell that this event is safely in syslog.
715 */
716int nvram_clear_error_log(void)
717{
718	loff_t tmp_index;
719	int clear_word = ERR_FLAG_ALREADY_LOGGED;
720	int rc;
721
722	tmp_index = nvram_error_log_index;
723
724	rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index);
725	if (rc <= 0) {
726		printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc);
727		return rc;
728	}
729
730	return 0;
731}
732
733#endif /* CONFIG_PPC_PSERIES */
734
735module_init(nvram_init);
736module_exit(nvram_cleanup);
737MODULE_LICENSE("GPL");
738