summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/platforms/pseries/nvram.c
blob: cbf1720eb4aadcae3d208e69e7d530e80d9c3a1e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  c 2001 PPC 64 Team, IBM Corp
 *
 * /dev/nvram driver for PPC64
 */


#include <linux/types.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/uaccess.h>
#include <linux/of.h>
#include <asm/nvram.h>
#include <asm/rtas.h>
#include <asm/machdep.h>

/* Max bytes to read/write in one go */
#define NVRW_CNT 0x20

static unsigned int nvram_size;
static int nvram_fetch, nvram_store;
static char nvram_buf[NVRW_CNT];	/* assume this is in the first 4GB */
static DEFINE_SPINLOCK(nvram_lock);

/* See clobbering_unread_rtas_event() */
#define NVRAM_RTAS_READ_TIMEOUT 5		/* seconds */
static time64_t last_unread_rtas_event;		/* timestamp */

#ifdef CONFIG_PSTORE
time64_t last_rtas_event;
#endif

static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index)
{
	unsigned int i;
	unsigned long len;
	int done;
	unsigned long flags;
	char *p = buf;


	if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE)
		return -ENODEV;

	if (*index >= nvram_size)
		return 0;

	i = *index;
	if (i + count > nvram_size)
		count = nvram_size - i;

	spin_lock_irqsave(&nvram_lock, flags);

	for (; count != 0; count -= len) {
		len = count;
		if (len > NVRW_CNT)
			len = NVRW_CNT;
		
		if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf),
			       len) != 0) || len != done) {
			spin_unlock_irqrestore(&nvram_lock, flags);
			return -EIO;
		}
		
		memcpy(p, nvram_buf, len);

		p += len;
		i += len;
	}

	spin_unlock_irqrestore(&nvram_lock, flags);
	
	*index = i;
	return p - buf;
}

static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index)
{
	unsigned int i;
	unsigned long len;
	int done;
	unsigned long flags;
	const char *p = buf;

	if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE)
		return -ENODEV;

	if (*index >= nvram_size)
		return 0;

	i = *index;
	if (i + count > nvram_size)
		count = nvram_size - i;

	spin_lock_irqsave(&nvram_lock, flags);

	for (; count != 0; count -= len) {
		len = count;
		if (len > NVRW_CNT)
			len = NVRW_CNT;

		memcpy(nvram_buf, p, len);

		if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf),
			       len) != 0) || len != done) {
			spin_unlock_irqrestore(&nvram_lock, flags);
			return -EIO;
		}
		
		p += len;
		i += len;
	}
	spin_unlock_irqrestore(&nvram_lock, flags);
	
	*index = i;
	return p - buf;
}

static ssize_t pSeries_nvram_get_size(void)
{
	return nvram_size ? nvram_size : -ENODEV;
}

/* nvram_write_error_log
 *
 * We need to buffer the error logs into nvram to ensure that we have
 * the failure information to decode.
 */
int nvram_write_error_log(char * buff, int length,
                          unsigned int err_type, unsigned int error_log_cnt)
{
	int rc = nvram_write_os_partition(&rtas_log_partition, buff, length,
						err_type, error_log_cnt);
	if (!rc) {
		last_unread_rtas_event = ktime_get_real_seconds();
#ifdef CONFIG_PSTORE
		last_rtas_event = ktime_get_real_seconds();
#endif
	}

	return rc;
}

/* nvram_read_error_log
 *
 * Reads nvram for error log for at most 'length'
 */
int nvram_read_error_log(char *buff, int length,
			unsigned int *err_type, unsigned int *error_log_cnt)
{
	return nvram_read_partition(&rtas_log_partition, buff, length,
						err_type, error_log_cnt);
}

/* This doesn't actually zero anything, but it sets the event_logged
 * word to tell that this event is safely in syslog.
 */
int nvram_clear_error_log(void)
{
	loff_t tmp_index;
	int clear_word = ERR_FLAG_ALREADY_LOGGED;
	int rc;

	if (rtas_log_partition.index == -1)
		return -1;

	tmp_index = rtas_log_partition.index;
	
	rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index);
	if (rc <= 0) {
		printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc);
		return rc;
	}
	last_unread_rtas_event = 0;

	return 0;
}

/*
 * Are we using the ibm,rtas-log for oops/panic reports?  And if so,
 * would logging this oops/panic overwrite an RTAS event that rtas_errd
 * hasn't had a chance to read and process?  Return 1 if so, else 0.
 *
 * We assume that if rtas_errd hasn't read the RTAS event in
 * NVRAM_RTAS_READ_TIMEOUT seconds, it's probably not going to.
 */
int clobbering_unread_rtas_event(void)
{
	return (oops_log_partition.index == rtas_log_partition.index
		&& last_unread_rtas_event
		&& ktime_get_real_seconds() - last_unread_rtas_event <=
						NVRAM_RTAS_READ_TIMEOUT);
}

static int __init pseries_nvram_init_log_partitions(void)
{
	int rc;

	/* Scan nvram for partitions */
	nvram_scan_partitions();

	rc = nvram_init_os_partition(&rtas_log_partition);
	nvram_init_oops_partition(rc == 0);
	return 0;
}
machine_arch_initcall(pseries, pseries_nvram_init_log_partitions);

int __init pSeries_nvram_init(void)
{
	struct device_node *nvram;
	const __be32 *nbytes_p;
	unsigned int proplen;

	nvram = of_find_node_by_type(NULL, "nvram");
	if (nvram == NULL)
		return -ENODEV;

	nbytes_p = of_get_property(nvram, "#bytes", &proplen);
	if (nbytes_p == NULL || proplen != sizeof(unsigned int)) {
		of_node_put(nvram);
		return -EIO;
	}

	nvram_size = be32_to_cpup(nbytes_p);

	nvram_fetch = rtas_token("nvram-fetch");
	nvram_store = rtas_token("nvram-store");
	printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size);
	of_node_put(nvram);

	ppc_md.nvram_read	= pSeries_nvram_read;
	ppc_md.nvram_write	= pSeries_nvram_write;
	ppc_md.nvram_size	= pSeries_nvram_get_size;

	return 0;
}