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 * +---+-------+--------------------------------------------------------------+ 41 * |...| | RESERVED = MBZ | 42 * +---+-------+--------------------------------------------------------------+ 43 * | 15| 31:0 | RESERVED = MBZ | 44 * +---+-------+--------------------------------------------------------------+ 45 */ 46 47 struct guc_ct_buffer_desc { 48 u32 head; 49 u32 tail; 50 u32 status; 51 #define GUC_CTB_STATUS_NO_ERROR 0 52 #define GUC_CTB_STATUS_OVERFLOW (1 << 0) 53 #define GUC_CTB_STATUS_UNDERFLOW (1 << 1) 54 #define GUC_CTB_STATUS_MISMATCH (1 << 2) 55 #define GUC_CTB_STATUS_DISABLED (1 << 3) 56 u32 reserved[13]; 57 } __packed; 58 static_assert(sizeof(struct guc_ct_buffer_desc) == 64); 59 60 /** 61 * DOC: CTB Message 62 * 63 * +---+-------+--------------------------------------------------------------+ 64 * | | Bits | Description | 65 * +===+=======+==============================================================+ 66 * | 0 | 31:16 | **FENCE** - message identifier | 67 * | +-------+--------------------------------------------------------------+ 68 * | | 15:12 | **FORMAT** - format of the CTB message | 69 * | | | - _`GUC_CTB_FORMAT_HXG` = 0 - see `CTB HXG Message`_ | 70 * | +-------+--------------------------------------------------------------+ 71 * | | 11:8 | **RESERVED** | 72 * | +-------+--------------------------------------------------------------+ 73 * | | 7:0 | **NUM_DWORDS** - length of the CTB message (w/o header) | 74 * +---+-------+--------------------------------------------------------------+ 75 * | 1 | 31:0 | optional (depends on FORMAT) | 76 * +---+-------+ | 77 * |...| | | 78 * +---+-------+ | 79 * | n | 31:0 | | 80 * +---+-------+--------------------------------------------------------------+ 81 */ 82 83 #define GUC_CTB_HDR_LEN 1u 84 #define GUC_CTB_MSG_MIN_LEN GUC_CTB_HDR_LEN 85 #define GUC_CTB_MSG_MAX_LEN (GUC_CTB_MSG_MIN_LEN + GUC_CTB_MAX_DWORDS) 86 #define GUC_CTB_MSG_0_FENCE (0xffffu << 16) 87 #define GUC_CTB_MSG_0_FORMAT (0xfu << 12) 88 #define GUC_CTB_FORMAT_HXG 0u 89 #define GUC_CTB_MSG_0_RESERVED (0xfu << 8) 90 #define GUC_CTB_MSG_0_NUM_DWORDS (0xffu << 0) 91 #define GUC_CTB_MAX_DWORDS 255 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 maintained in the `CTB Descriptor`_. 126 * Each message in data stream is encoded as `CTB HXG Message`_. 127 */ 128 129 #endif 130