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
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* PowerNV SCOM bus debugfs interface
*
* Copyright 2010 Benjamin Herrenschmidt, IBM Corp
* <benh@kernel.crashing.org>
* and David Gibson, IBM Corporation.
* Copyright 2013 IBM Corp.
*/
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/bug.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/debugfs.h>
#include <asm/machdep.h>
#include <asm/firmware.h>
#include <asm/opal.h>
#include <asm/prom.h>
static u64 opal_scom_unmangle(u64 addr)
{
u64 tmp;
/*
* XSCOM addresses use the top nibble to set indirect mode and
* its form. Bits 4-11 are always 0.
*
* Because the debugfs interface uses signed offsets and shifts
* the address left by 3, we basically cannot use the top 4 bits
* of the 64-bit address, and thus cannot use the indirect bit.
*
* To deal with that, we support the indirect bits being in
* bits 4-7 (IBM notation) instead of bit 0-3 in this API, we
* do the conversion here.
*
* For in-kernel use, we don't need to do this mangling. In
* kernel won't have bits 4-7 set.
*
* So:
* debugfs will always set 0-3 = 0 and clear 4-7
* kernel will always clear 0-3 = 0 and set 4-7
*/
tmp = addr;
tmp &= 0x0f00000000000000;
addr &= 0xf0ffffffffffffff;
addr |= tmp << 4;
return addr;
}
static int opal_scom_read(uint32_t chip, uint64_t addr, u64 reg, u64 *value)
{
int64_t rc;
__be64 v;
reg = opal_scom_unmangle(addr + reg);
rc = opal_xscom_read(chip, reg, (__be64 *)__pa(&v));
if (rc) {
*value = 0xfffffffffffffffful;
return -EIO;
}
*value = be64_to_cpu(v);
return 0;
}
static int opal_scom_write(uint32_t chip, uint64_t addr, u64 reg, u64 value)
{
int64_t rc;
reg = opal_scom_unmangle(addr + reg);
rc = opal_xscom_write(chip, reg, value);
if (rc)
return -EIO;
return 0;
}
struct scom_debug_entry {
u32 chip;
struct debugfs_blob_wrapper path;
char name[16];
};
static ssize_t scom_debug_read(struct file *filp, char __user *ubuf,
size_t count, loff_t *ppos)
{
struct scom_debug_entry *ent = filp->private_data;
u64 __user *ubuf64 = (u64 __user *)ubuf;
loff_t off = *ppos;
ssize_t done = 0;
u64 reg, reg_base, reg_cnt, val;
int rc;
if (off < 0 || (off & 7) || (count & 7))
return -EINVAL;
reg_base = off >> 3;
reg_cnt = count >> 3;
for (reg = 0; reg < reg_cnt; reg++) {
rc = opal_scom_read(ent->chip, reg_base, reg, &val);
if (!rc)
rc = put_user(val, ubuf64);
if (rc) {
if (!done)
done = rc;
break;
}
ubuf64++;
*ppos += 8;
done += 8;
}
return done;
}
static ssize_t scom_debug_write(struct file *filp, const char __user *ubuf,
size_t count, loff_t *ppos)
{
struct scom_debug_entry *ent = filp->private_data;
u64 __user *ubuf64 = (u64 __user *)ubuf;
loff_t off = *ppos;
ssize_t done = 0;
u64 reg, reg_base, reg_cnt, val;
int rc;
if (off < 0 || (off & 7) || (count & 7))
return -EINVAL;
reg_base = off >> 3;
reg_cnt = count >> 3;
for (reg = 0; reg < reg_cnt; reg++) {
rc = get_user(val, ubuf64);
if (!rc)
rc = opal_scom_write(ent->chip, reg_base, reg, val);
if (rc) {
if (!done)
done = rc;
break;
}
ubuf64++;
done += 8;
}
return done;
}
static const struct file_operations scom_debug_fops = {
.read = scom_debug_read,
.write = scom_debug_write,
.open = simple_open,
.llseek = default_llseek,
};
static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
int chip)
{
struct scom_debug_entry *ent;
struct dentry *dir;
ent = kzalloc(sizeof(*ent), GFP_KERNEL);
if (!ent)
return -ENOMEM;
ent->chip = chip;
snprintf(ent->name, 16, "%08x", chip);
ent->path.data = (void *)kasprintf(GFP_KERNEL, "%pOF", dn);
if (!ent->path.data) {
kfree(ent);
return -ENOMEM;
}
ent->path.size = strlen((char *)ent->path.data);
dir = debugfs_create_dir(ent->name, root);
if (IS_ERR(dir)) {
kfree(ent->path.data);
kfree(ent);
return -1;
}
debugfs_create_blob("devspec", 0400, dir, &ent->path);
debugfs_create_file("access", 0600, dir, ent, &scom_debug_fops);
return 0;
}
static int scom_debug_init(void)
{
struct device_node *dn;
struct dentry *root;
int chip, rc;
if (!firmware_has_feature(FW_FEATURE_OPAL))
return 0;
root = debugfs_create_dir("scom", arch_debugfs_dir);
if (IS_ERR(root))
return -1;
rc = 0;
for_each_node_with_property(dn, "scom-controller") {
chip = of_get_ibm_chip_id(dn);
WARN_ON(chip == -1);
rc |= scom_debug_init_one(root, dn, chip);
}
return rc;
}
device_initcall(scom_debug_init);
|
