1/* SPDX-License-Identifier: MIT */
2/*
3 * Copyright © 2023 Intel Corporation
4 */
5
6#ifndef __DRM_ELD_H__
7#define __DRM_ELD_H__
8
9#include <linux/types.h>
10
11struct cea_sad;
12
13/* ELD Header Block */
14#define DRM_ELD_HEADER_BLOCK_SIZE 4
15
16#define DRM_ELD_VER 0
17# define DRM_ELD_VER_SHIFT 3
18# define DRM_ELD_VER_MASK (0x1f << 3)
19# define DRM_ELD_VER_CEA861D (2 << 3) /* supports 861D or below */
20# define DRM_ELD_VER_CANNED (0x1f << 3)
21
22#define DRM_ELD_BASELINE_ELD_LEN 2 /* in dwords! */
23
24/* ELD Baseline Block for ELD_Ver == 2 */
25#define DRM_ELD_CEA_EDID_VER_MNL 4
26# define DRM_ELD_CEA_EDID_VER_SHIFT 5
27# define DRM_ELD_CEA_EDID_VER_MASK (7 << 5)
28# define DRM_ELD_CEA_EDID_VER_NONE (0 << 5)
29# define DRM_ELD_CEA_EDID_VER_CEA861 (1 << 5)
30# define DRM_ELD_CEA_EDID_VER_CEA861A (2 << 5)
31# define DRM_ELD_CEA_EDID_VER_CEA861BCD (3 << 5)
32# define DRM_ELD_MNL_SHIFT 0
33# define DRM_ELD_MNL_MASK (0x1f << 0)
34
35#define DRM_ELD_SAD_COUNT_CONN_TYPE 5
36# define DRM_ELD_SAD_COUNT_SHIFT 4
37# define DRM_ELD_SAD_COUNT_MASK (0xf << 4)
38# define DRM_ELD_CONN_TYPE_SHIFT 2
39# define DRM_ELD_CONN_TYPE_MASK (3 << 2)
40# define DRM_ELD_CONN_TYPE_HDMI (0 << 2)
41# define DRM_ELD_CONN_TYPE_DP (1 << 2)
42# define DRM_ELD_SUPPORTS_AI (1 << 1)
43# define DRM_ELD_SUPPORTS_HDCP (1 << 0)
44
45#define DRM_ELD_AUD_SYNCH_DELAY 6 /* in units of 2 ms */
46# define DRM_ELD_AUD_SYNCH_DELAY_MAX 0xfa /* 500 ms */
47
48#define DRM_ELD_SPEAKER 7
49# define DRM_ELD_SPEAKER_MASK 0x7f
50# define DRM_ELD_SPEAKER_RLRC (1 << 6)
51# define DRM_ELD_SPEAKER_FLRC (1 << 5)
52# define DRM_ELD_SPEAKER_RC (1 << 4)
53# define DRM_ELD_SPEAKER_RLR (1 << 3)
54# define DRM_ELD_SPEAKER_FC (1 << 2)
55# define DRM_ELD_SPEAKER_LFE (1 << 1)
56# define DRM_ELD_SPEAKER_FLR (1 << 0)
57
58#define DRM_ELD_PORT_ID 8 /* offsets 8..15 inclusive */
59# define DRM_ELD_PORT_ID_LEN 8
60
61#define DRM_ELD_MANUFACTURER_NAME0 16
62#define DRM_ELD_MANUFACTURER_NAME1 17
63
64#define DRM_ELD_PRODUCT_CODE0 18
65#define DRM_ELD_PRODUCT_CODE1 19
66
67#define DRM_ELD_MONITOR_NAME_STRING 20 /* offsets 20..(20+mnl-1) inclusive */
68
69#define DRM_ELD_CEA_SAD(mnl, sad) (20 + (mnl) + 3 * (sad))
70
71/**
72 * drm_eld_mnl - Get ELD monitor name length in bytes.
73 * @eld: pointer to an eld memory structure with mnl set
74 */
75static inline int drm_eld_mnl(const u8 *eld)
76{
77 return (eld[DRM_ELD_CEA_EDID_VER_MNL] & DRM_ELD_MNL_MASK) >> DRM_ELD_MNL_SHIFT;
78}
79
80int drm_eld_sad_get(const u8 *eld, int sad_index, struct cea_sad *cta_sad);
81int drm_eld_sad_set(u8 *eld, int sad_index, const struct cea_sad *cta_sad);
82
83/**
84 * drm_eld_sad - Get ELD SAD structures.
85 * @eld: pointer to an eld memory structure with sad_count set
86 */
87static inline const u8 *drm_eld_sad(const u8 *eld)
88{
89 unsigned int ver, mnl;
90
91 ver = (eld[DRM_ELD_VER] & DRM_ELD_VER_MASK) >> DRM_ELD_VER_SHIFT;
92 if (ver != 2 && ver != 31)
93 return NULL;
94
95 mnl = drm_eld_mnl(eld);
96 if (mnl > 16)
97 return NULL;
98
99 return eld + DRM_ELD_CEA_SAD(mnl, 0);
100}
101
102/**
103 * drm_eld_sad_count - Get ELD SAD count.
104 * @eld: pointer to an eld memory structure with sad_count set
105 */
106static inline int drm_eld_sad_count(const u8 *eld)
107{
108 return (eld[DRM_ELD_SAD_COUNT_CONN_TYPE] & DRM_ELD_SAD_COUNT_MASK) >>
109 DRM_ELD_SAD_COUNT_SHIFT;
110}
111
112/**
113 * drm_eld_calc_baseline_block_size - Calculate baseline block size in bytes
114 * @eld: pointer to an eld memory structure with mnl and sad_count set
115 *
116 * This is a helper for determining the payload size of the baseline block, in
117 * bytes, for e.g. setting the Baseline_ELD_Len field in the ELD header block.
118 */
119static inline int drm_eld_calc_baseline_block_size(const u8 *eld)
120{
121 return DRM_ELD_MONITOR_NAME_STRING - DRM_ELD_HEADER_BLOCK_SIZE +
122 drm_eld_mnl(eld) + drm_eld_sad_count(eld) * 3;
123}
124
125/**
126 * drm_eld_size - Get ELD size in bytes
127 * @eld: pointer to a complete eld memory structure
128 *
129 * The returned value does not include the vendor block. It's vendor specific,
130 * and comprises of the remaining bytes in the ELD memory buffer after
131 * drm_eld_size() bytes of header and baseline block.
132 *
133 * The returned value is guaranteed to be a multiple of 4.
134 */
135static inline int drm_eld_size(const u8 *eld)
136{
137 return DRM_ELD_HEADER_BLOCK_SIZE + eld[DRM_ELD_BASELINE_ELD_LEN] * 4;
138}
139
140/**
141 * drm_eld_get_spk_alloc - Get speaker allocation
142 * @eld: pointer to an ELD memory structure
143 *
144 * The returned value is the speakers mask. User has to use %DRM_ELD_SPEAKER
145 * field definitions to identify speakers.
146 */
147static inline u8 drm_eld_get_spk_alloc(const u8 *eld)
148{
149 return eld[DRM_ELD_SPEAKER] & DRM_ELD_SPEAKER_MASK;
150}
151
152/**
153 * drm_eld_get_conn_type - Get device type hdmi/dp connected
154 * @eld: pointer to an ELD memory structure
155 *
156 * The caller need to use %DRM_ELD_CONN_TYPE_HDMI or %DRM_ELD_CONN_TYPE_DP to
157 * identify the display type connected.
158 */
159static inline u8 drm_eld_get_conn_type(const u8 *eld)
160{
161 return eld[DRM_ELD_SAD_COUNT_CONN_TYPE] & DRM_ELD_CONN_TYPE_MASK;
162}
163
164#endif /* __DRM_ELD_H__ */
165

source code of linux/include/drm/drm_eld.h