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
|
// SPDX-License-Identifier: MIT
/*
* Copyright © 2021 Intel Corporation
*/
#include <drm/drm_displayid.h>
#include <drm/drm_edid.h>
#include <drm/drm_print.h>
static const struct displayid_header *
displayid_get_header(const u8 *displayid, int length, int index)
{
const struct displayid_header *base;
if (sizeof(*base) > length - index)
return ERR_PTR(-EINVAL);
base = (const struct displayid_header *)&displayid[index];
return base;
}
static const struct displayid_header *
validate_displayid(const u8 *displayid, int length, int idx)
{
int i, dispid_length;
u8 csum = 0;
const struct displayid_header *base;
base = displayid_get_header(displayid, length, idx);
if (IS_ERR(base))
return base;
DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n",
base->rev, base->bytes, base->prod_id, base->ext_count);
/* +1 for DispID checksum */
dispid_length = sizeof(*base) + base->bytes + 1;
if (dispid_length > length - idx)
return ERR_PTR(-EINVAL);
for (i = 0; i < dispid_length; i++)
csum += displayid[idx + i];
if (csum) {
DRM_NOTE("DisplayID checksum invalid, remainder is %d\n", csum);
return ERR_PTR(-EINVAL);
}
return base;
}
static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid,
int *length, int *idx,
int *ext_index)
{
const u8 *displayid = drm_find_edid_extension(drm_edid, DISPLAYID_EXT, ext_index);
const struct displayid_header *base;
if (!displayid)
return NULL;
/* EDID extensions block checksum isn't for us */
*length = EDID_LENGTH - 1;
*idx = 1;
base = validate_displayid(displayid, *length, *idx);
if (IS_ERR(base))
return NULL;
*length = *idx + sizeof(*base) + base->bytes;
return displayid;
}
void displayid_iter_edid_begin(const struct drm_edid *drm_edid,
struct displayid_iter *iter)
{
memset(iter, 0, sizeof(*iter));
iter->drm_edid = drm_edid;
}
static const struct displayid_block *
displayid_iter_block(const struct displayid_iter *iter)
{
const struct displayid_block *block;
if (!iter->section)
return NULL;
block = (const struct displayid_block *)&iter->section[iter->idx];
if (iter->idx + sizeof(*block) <= iter->length &&
iter->idx + sizeof(*block) + block->num_bytes <= iter->length)
return block;
return NULL;
}
const struct displayid_block *
__displayid_iter_next(struct displayid_iter *iter)
{
const struct displayid_block *block;
if (!iter->drm_edid)
return NULL;
if (iter->section) {
/* current block should always be valid */
block = displayid_iter_block(iter);
if (WARN_ON(!block)) {
iter->section = NULL;
iter->drm_edid = NULL;
return NULL;
}
/* next block in section */
iter->idx += sizeof(*block) + block->num_bytes;
block = displayid_iter_block(iter);
if (block)
return block;
}
for (;;) {
/* The first section we encounter is the base section */
bool base_section = !iter->section;
iter->section = drm_find_displayid_extension(iter->drm_edid,
&iter->length,
&iter->idx,
&iter->ext_index);
if (!iter->section) {
iter->drm_edid = NULL;
return NULL;
}
/* Save the structure version and primary use case. */
if (base_section) {
const struct displayid_header *base;
base = displayid_get_header(iter->section, iter->length,
iter->idx);
if (!IS_ERR(base)) {
iter->version = base->rev;
iter->primary_use = base->prod_id;
}
}
iter->idx += sizeof(struct displayid_header);
block = displayid_iter_block(iter);
if (block)
return block;
}
}
void displayid_iter_end(struct displayid_iter *iter)
{
memset(iter, 0, sizeof(*iter));
}
/* DisplayID Structure Version/Revision from the Base Section. */
u8 displayid_version(const struct displayid_iter *iter)
{
return iter->version;
}
/*
* DisplayID Primary Use Case (2.0+) or Product Type Identifier (1.0-1.3) from
* the Base Section.
*/
u8 displayid_primary_use(const struct displayid_iter *iter)
{
return iter->primary_use;
}
|
