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
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* PowerNV OPAL in-memory console interface
*
* Copyright 2014 IBM Corp.
*/
#include <asm/io.h>
#include <asm/opal.h>
#include <linux/debugfs.h>
#include <linux/of.h>
#include <linux/types.h>
#include <asm/barrier.h>
/* OPAL in-memory console. Defined in OPAL source at core/console.c */
struct memcons {
__be64 magic;
#define MEMCONS_MAGIC 0x6630696567726173L
__be64 obuf_phys;
__be64 ibuf_phys;
__be32 obuf_size;
__be32 ibuf_size;
__be32 out_pos;
#define MEMCONS_OUT_POS_WRAP 0x80000000u
#define MEMCONS_OUT_POS_MASK 0x00ffffffu
__be32 in_prod;
__be32 in_cons;
};
static struct memcons *opal_memcons = NULL;
ssize_t memcons_copy(struct memcons *mc, char *to, loff_t pos, size_t count)
{
const char *conbuf;
ssize_t ret;
size_t first_read = 0;
uint32_t out_pos, avail;
if (!mc)
return -ENODEV;
out_pos = be32_to_cpu(READ_ONCE(mc->out_pos));
/* Now we've read out_pos, put a barrier in before reading the new
* data it points to in conbuf. */
smp_rmb();
conbuf = phys_to_virt(be64_to_cpu(mc->obuf_phys));
/* When the buffer has wrapped, read from the out_pos marker to the end
* of the buffer, and then read the remaining data as in the un-wrapped
* case. */
if (out_pos & MEMCONS_OUT_POS_WRAP) {
out_pos &= MEMCONS_OUT_POS_MASK;
avail = be32_to_cpu(mc->obuf_size) - out_pos;
ret = memory_read_from_buffer(to, count, &pos,
conbuf + out_pos, avail);
if (ret < 0)
goto out;
first_read = ret;
to += first_read;
count -= first_read;
pos -= avail;
if (count <= 0)
goto out;
}
/* Sanity check. The firmware should not do this to us. */
if (out_pos > be32_to_cpu(mc->obuf_size)) {
pr_err("OPAL: memory console corruption. Aborting read.\n");
return -EINVAL;
}
ret = memory_read_from_buffer(to, count, &pos, conbuf, out_pos);
if (ret < 0)
goto out;
ret += first_read;
out:
return ret;
}
ssize_t opal_msglog_copy(char *to, loff_t pos, size_t count)
{
return memcons_copy(opal_memcons, to, pos, count);
}
static ssize_t opal_msglog_read(struct file *file, struct kobject *kobj,
struct bin_attribute *bin_attr, char *to,
loff_t pos, size_t count)
{
return opal_msglog_copy(to, pos, count);
}
static struct bin_attribute opal_msglog_attr = {
.attr = {.name = "msglog", .mode = 0400},
.read = opal_msglog_read
};
struct memcons *memcons_init(struct device_node *node, const char *mc_prop_name)
{
u64 mcaddr;
struct memcons *mc;
if (of_property_read_u64(node, mc_prop_name, &mcaddr)) {
pr_warn("%s property not found, no message log\n",
mc_prop_name);
goto out_err;
}
mc = phys_to_virt(mcaddr);
if (!mc) {
pr_warn("memory console address is invalid\n");
goto out_err;
}
if (be64_to_cpu(mc->magic) != MEMCONS_MAGIC) {
pr_warn("memory console version is invalid\n");
goto out_err;
}
return mc;
out_err:
return NULL;
}
u32 memcons_get_size(struct memcons *mc)
{
return be32_to_cpu(mc->ibuf_size) + be32_to_cpu(mc->obuf_size);
}
void __init opal_msglog_init(void)
{
opal_memcons = memcons_init(opal_node, "ibm,opal-memcons");
if (!opal_memcons) {
pr_warn("OPAL: memcons failed to load from ibm,opal-memcons\n");
return;
}
opal_msglog_attr.size = memcons_get_size(opal_memcons);
}
void __init opal_msglog_sysfs_init(void)
{
if (!opal_memcons) {
pr_warn("OPAL: message log initialisation failed, not creating sysfs entry\n");
return;
}
if (sysfs_create_bin_file(opal_kobj, &opal_msglog_attr) != 0)
pr_warn("OPAL: sysfs file creation failed\n");
}
|
