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
/* SPDX-License-Identifier: MIT */
/*
* Copyright © 2014-2021 Intel Corporation
*/
#ifndef _ABI_GUC_COMMUNICATION_CTB_ABI_H
#define _ABI_GUC_COMMUNICATION_CTB_ABI_H
#include <linux/types.h>
#include <linux/build_bug.h>
#include "guc_messages_abi.h"
/**
* DOC: CT Buffer
*
* Circular buffer used to send `CTB Message`_
*/
/**
* DOC: CTB Descriptor
*
* +---+-------+--------------------------------------------------------------+
* | | Bits | Description |
* +===+=======+==============================================================+
* | 0 | 31:0 | **HEAD** - offset (in dwords) to the last dword that was |
* | | | read from the `CT Buffer`_. |
* | | | It can only be updated by the receiver. |
* +---+-------+--------------------------------------------------------------+
* | 1 | 31:0 | **TAIL** - offset (in dwords) to the last dword that was |
* | | | written to the `CT Buffer`_. |
* | | | It can only be updated by the sender. |
* +---+-------+--------------------------------------------------------------+
* | 2 | 31:0 | **STATUS** - status of the CTB |
* | | | |
* | | | - _`GUC_CTB_STATUS_NO_ERROR` = 0 (normal operation) |
* | | | - _`GUC_CTB_STATUS_OVERFLOW` = 1 (head/tail too large) |
* | | | - _`GUC_CTB_STATUS_UNDERFLOW` = 2 (truncated message) |
* | | | - _`GUC_CTB_STATUS_MISMATCH` = 4 (head/tail modified) |
* +---+-------+--------------------------------------------------------------+
* |...| | RESERVED = MBZ |
* +---+-------+--------------------------------------------------------------+
* | 15| 31:0 | RESERVED = MBZ |
* +---+-------+--------------------------------------------------------------+
*/
struct guc_ct_buffer_desc {
u32 head;
u32 tail;
u32 status;
#define GUC_CTB_STATUS_NO_ERROR 0
#define GUC_CTB_STATUS_OVERFLOW (1 << 0)
#define GUC_CTB_STATUS_UNDERFLOW (1 << 1)
#define GUC_CTB_STATUS_MISMATCH (1 << 2)
#define GUC_CTB_STATUS_DISABLED (1 << 3)
u32 reserved[13];
} __packed;
static_assert(sizeof(struct guc_ct_buffer_desc) == 64);
/**
* DOC: CTB Message
*
* +---+-------+--------------------------------------------------------------+
* | | Bits | Description |
* +===+=======+==============================================================+
* | 0 | 31:16 | **FENCE** - message identifier |
* | +-------+--------------------------------------------------------------+
* | | 15:12 | **FORMAT** - format of the CTB message |
* | | | - _`GUC_CTB_FORMAT_HXG` = 0 - see `CTB HXG Message`_ |
* | +-------+--------------------------------------------------------------+
* | | 11:8 | **RESERVED** |
* | +-------+--------------------------------------------------------------+
* | | 7:0 | **NUM_DWORDS** - length of the CTB message (w/o header) |
* +---+-------+--------------------------------------------------------------+
* | 1 | 31:0 | optional (depends on FORMAT) |
* +---+-------+ |
* |...| | |
* +---+-------+ |
* | n | 31:0 | |
* +---+-------+--------------------------------------------------------------+
*/
#define GUC_CTB_HDR_LEN 1u
#define GUC_CTB_MSG_MIN_LEN GUC_CTB_HDR_LEN
#define GUC_CTB_MSG_MAX_LEN (GUC_CTB_MSG_MIN_LEN + GUC_CTB_MAX_DWORDS)
#define GUC_CTB_MSG_0_FENCE (0xffffu << 16)
#define GUC_CTB_MSG_0_FORMAT (0xfu << 12)
#define GUC_CTB_FORMAT_HXG 0u
#define GUC_CTB_MSG_0_RESERVED (0xfu << 8)
#define GUC_CTB_MSG_0_NUM_DWORDS (0xffu << 0)
#define GUC_CTB_MAX_DWORDS 255
/**
* DOC: CTB HXG Message
*
* +---+-------+--------------------------------------------------------------+
* | | Bits | Description |
* +===+=======+==============================================================+
* | 0 | 31:16 | FENCE |
* | +-------+--------------------------------------------------------------+
* | | 15:12 | FORMAT = GUC_CTB_FORMAT_HXG_ |
* | +-------+--------------------------------------------------------------+
* | | 11:8 | RESERVED = MBZ |
* | +-------+--------------------------------------------------------------+
* | | 7:0 | NUM_DWORDS = length (in dwords) of the embedded HXG message |
* +---+-------+--------------------------------------------------------------+
* | 1 | 31:0 | |
* +---+-------+ |
* |...| | [Embedded `HXG Message`_] |
* +---+-------+ |
* | n | 31:0 | |
* +---+-------+--------------------------------------------------------------+
*/
#define GUC_CTB_HXG_MSG_MIN_LEN (GUC_CTB_MSG_MIN_LEN + GUC_HXG_MSG_MIN_LEN)
#define GUC_CTB_HXG_MSG_MAX_LEN GUC_CTB_MSG_MAX_LEN
/**
* DOC: CTB based communication
*
* The CTB (command transport buffer) communication between Host and GuC
* is based on u32 data stream written to the shared buffer. One buffer can
* be used to transmit data only in one direction (one-directional channel).
*
* Current status of the each buffer is maintained in the `CTB Descriptor`_.
* Each message in data stream is encoded as `CTB HXG Message`_.
*/
#endif