1 /* SPDX-License-Identifier: MIT */ 2 /* 3 * Copyright © 2014-2021 Intel Corporation 4 */ 5 6 #ifndef _ABI_GUC_COMMUNICATION_CTB_ABI_H 7 #define _ABI_GUC_COMMUNICATION_CTB_ABI_H 8 9 #include <linux/types.h> 10 #include <linux/build_bug.h> 11 12 #include "guc_messages_abi.h" 13 14 /** 15 * DOC: CT Buffer 16 * 17 * Circular buffer used to send `CTB Message`_ 18 */ 19 20 /** 21 * DOC: CTB Descriptor 22 * 23 * +---+-------+--------------------------------------------------------------+ 24 * | | Bits | Description | 25 * +===+=======+==============================================================+ 26 * | 0 | 31:0 | **HEAD** - offset (in dwords) to the last dword that was | 27 * | | | read from the `CT Buffer`_. | 28 * | | | It can only be updated by the receiver. | 29 * +---+-------+--------------------------------------------------------------+ 30 * | 1 | 31:0 | **TAIL** - offset (in dwords) to the last dword that was | 31 * | | | written to the `CT Buffer`_. | 32 * | | | It can only be updated by the sender. | 33 * +---+-------+--------------------------------------------------------------+ 34 * | 2 | 31:0 | **STATUS** - status of the CTB | 35 * | | | | 36 * | | | - _`GUC_CTB_STATUS_NO_ERROR` = 0 (normal operation) | 37 * | | | - _`GUC_CTB_STATUS_OVERFLOW` = 1 (head/tail too large) | 38 * | | | - _`GUC_CTB_STATUS_UNDERFLOW` = 2 (truncated message) | 39 * | | | - _`GUC_CTB_STATUS_MISMATCH` = 4 (head/tail modified) | 40 * | | | - _`GUC_CTB_STATUS_UNUSED` = 8 (CTB is not in use) | 41 * +---+-------+--------------------------------------------------------------+ 42 * |...| | RESERVED = MBZ | 43 * +---+-------+--------------------------------------------------------------+ 44 * | 15| 31:0 | RESERVED = MBZ | 45 * +---+-------+--------------------------------------------------------------+ 46 */ 47 48 struct guc_ct_buffer_desc { 49 u32 head; 50 u32 tail; 51 u32 status; 52 #define GUC_CTB_STATUS_NO_ERROR 0 53 #define GUC_CTB_STATUS_OVERFLOW BIT(0) 54 #define GUC_CTB_STATUS_UNDERFLOW BIT(1) 55 #define GUC_CTB_STATUS_MISMATCH BIT(2) 56 #define GUC_CTB_STATUS_UNUSED BIT(3) 57 u32 reserved[13]; 58 } __packed; 59 static_assert(sizeof(struct guc_ct_buffer_desc) == 64); 60 61 /** 62 * DOC: CTB Message 63 * 64 * +---+-------+--------------------------------------------------------------+ 65 * | | Bits | Description | 66 * +===+=======+==============================================================+ 67 * | 0 | 31:16 | **FENCE** - message identifier | 68 * | +-------+--------------------------------------------------------------+ 69 * | | 15:12 | **FORMAT** - format of the CTB message | 70 * | | | - _`GUC_CTB_FORMAT_HXG` = 0 - see `CTB HXG Message`_ | 71 * | +-------+--------------------------------------------------------------+ 72 * | | 11:8 | **RESERVED** | 73 * | +-------+--------------------------------------------------------------+ 74 * | | 7:0 | **NUM_DWORDS** - length of the CTB message (w/o header) | 75 * +---+-------+--------------------------------------------------------------+ 76 * | 1 | 31:0 | optional (depends on FORMAT) | 77 * +---+-------+ | 78 * |...| | | 79 * +---+-------+ | 80 * | n | 31:0 | | 81 * +---+-------+--------------------------------------------------------------+ 82 */ 83 84 #define GUC_CTB_HDR_LEN 1u 85 #define GUC_CTB_MSG_MIN_LEN GUC_CTB_HDR_LEN 86 #define GUC_CTB_MSG_MAX_LEN 256u 87 #define GUC_CTB_MSG_0_FENCE (0xffffU << 16) 88 #define GUC_CTB_MSG_0_FORMAT (0xf << 12) 89 #define GUC_CTB_FORMAT_HXG 0u 90 #define GUC_CTB_MSG_0_RESERVED (0xf << 8) 91 #define GUC_CTB_MSG_0_NUM_DWORDS (0xff << 0) 92 93 /** 94 * DOC: CTB HXG Message 95 * 96 * +---+-------+--------------------------------------------------------------+ 97 * | | Bits | Description | 98 * +===+=======+==============================================================+ 99 * | 0 | 31:16 | FENCE | 100 * | +-------+--------------------------------------------------------------+ 101 * | | 15:12 | FORMAT = GUC_CTB_FORMAT_HXG_ | 102 * | +-------+--------------------------------------------------------------+ 103 * | | 11:8 | RESERVED = MBZ | 104 * | +-------+--------------------------------------------------------------+ 105 * | | 7:0 | NUM_DWORDS = length (in dwords) of the embedded HXG message | 106 * +---+-------+--------------------------------------------------------------+ 107 * | 1 | 31:0 | | 108 * +---+-------+ | 109 * |...| | [Embedded `HXG Message`_] | 110 * +---+-------+ | 111 * | n | 31:0 | | 112 * +---+-------+--------------------------------------------------------------+ 113 */ 114 115 #define GUC_CTB_HXG_MSG_MIN_LEN (GUC_CTB_MSG_MIN_LEN + GUC_HXG_MSG_MIN_LEN) 116 #define GUC_CTB_HXG_MSG_MAX_LEN GUC_CTB_MSG_MAX_LEN 117 118 /** 119 * DOC: CTB based communication 120 * 121 * The CTB (command transport buffer) communication between Host and GuC 122 * is based on u32 data stream written to the shared buffer. One buffer can 123 * be used to transmit data only in one direction (one-directional channel). 124 * 125 * Current status of the each buffer is stored in the buffer descriptor. 126 * Buffer descriptor holds tail and head fields that represents active data 127 * stream. The tail field is updated by the data producer (sender), and head 128 * field is updated by the data consumer (receiver):: 129 * 130 * +------------+ 131 * | DESCRIPTOR | +=================+============+========+ 132 * +============+ | | MESSAGE(s) | | 133 * | address |--------->+=================+============+========+ 134 * +------------+ 135 * | head | ^-----head--------^ 136 * +------------+ 137 * | tail | ^---------tail-----------------^ 138 * +------------+ 139 * | size | ^---------------size--------------------^ 140 * +------------+ 141 * 142 * Each message in data stream starts with the single u32 treated as a header, 143 * followed by optional set of u32 data that makes message specific payload:: 144 * 145 * +------------+---------+---------+---------+ 146 * | MESSAGE | 147 * +------------+---------+---------+---------+ 148 * | msg[0] | [1] | ... | [n-1] | 149 * +------------+---------+---------+---------+ 150 * | MESSAGE | MESSAGE PAYLOAD | 151 * + HEADER +---------+---------+---------+ 152 * | | 0 | ... | n | 153 * +======+=====+=========+=========+=========+ 154 * | 31:16| code| | | | 155 * +------+-----+ | | | 156 * | 15:5|flags| | | | 157 * +------+-----+ | | | 158 * | 4:0| len| | | | 159 * +------+-----+---------+---------+---------+ 160 * 161 * ^-------------len-------------^ 162 * 163 * The message header consists of: 164 * 165 * - **len**, indicates length of the message payload (in u32) 166 * - **code**, indicates message code 167 * - **flags**, holds various bits to control message handling 168 */ 169 170 #endif /* _ABI_GUC_COMMUNICATION_CTB_ABI_H */ 171