Tinh:
I suggest to separate this patch. The header file follows the industry
standard. New PCDs in DEC are for EDK2 implementation. They are different
changes. Please separate them.

Thanks
Liming
> -----邮件原件-----
> 发件人: Tinh Nguyen <tinhnguyen@os.amperecomputing.com>
> 发送时间: 2023年4月28日 12:00
> 收件人: devel@edk2.groups.io
> 抄送: patches@amperecomputing.com; michael.d.kinney@intel.com;
> gaoliming@byosoft.com.cn; zhiguang.liu@intel.com; abner.chang@amd.com;
> Tinh Nguyen <tinhnguyen@os.amperecomputing.com>
> 主题: [PATCH 1/2] MdePkg/IndustryStandard: Adds definitions for IPMI SSIF
>
> Specification reference:
> https://www.intel.com/content/www/us/en/products/docs/servers/ipmi/ip
> mi-second-gen-interface-spec-v2-rev1-1.html
>
> Signed-off-by: Tinh Nguyen <tinhnguyen@os.amperecomputing.com>
> ---
> MdePkg/MdePkg.dec | 26 ++++++
> MdePkg/Include/IndustryStandard/IpmiSsif.h | 98 ++++++++++++++++++++
> 2 files changed, 124 insertions(+)
>
> diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
> index 7488ccda7a00..518e4200e9af 100644
> --- a/MdePkg/MdePkg.dec
> +++ b/MdePkg/MdePkg.dec
> @@ -10,6 +10,7 @@
> # Copyright (c) 2022, Loongson Technology Corporation Limited. All rights
> reserved. 
> # Copyright (c) 2021 - 2022, Arm Limited. All rights reserved. 
> # Copyright (C) 2023 Advanced Micro Devices, Inc. All rights
reserved. 
> +# Copyright (c) 2023, Ampere Computing LLC. All rights reserved. 
> #
> # SPDX-License-Identifier: BSD-2-Clause-Patent
> #
> @@ -2353,6 +2354,31 @@ [PcdsFixedAtBuild,PcdsPatchableInModule]
> # @Prompt IPMI KCS Interface I/O Base Address
>
> gEfiMdePkgTokenSpaceGuid.PcdIpmiKcsIoBaseAddress|0xca2|UINT16|0x000
> 00031
>
> + ## This is SMBus slave address for the SSIF to the BMC.
> + # The recommended value defined by IPMI specification is 0x20 (section
> 12.12).
> + # @Prompt IPMI SSIF SMBus slave address
> +
> gEfiMdePkgTokenSpaceGuid.PcdIpmiSmbusSlaveAddr|0x20|UINT8|0x000000
> 32
> +
> + ## This is the maximum number of IPMI SSIF request retries.
> + # The IPMI specification specified min value is 5 (section 12.17).
> + # @Prompt Number of IPMI SSIF request retries.
> +
> gEfiMdePkgTokenSpaceGuid.PcdIpmiSsifRequestRetryCount|0x05|UINT8|0x0
> 0000033
> +
> + ## This is the required interval for each IPMI request retry.
> + # The IPMI specification specified a time range of 60ms to 250ms
> (section 12.17).
> + # The default setting is min.
> + # @Prompt Time between IPMI SSIF request retries.
> +
> gEfiMdePkgTokenSpaceGuid.PcdIpmiSsifRequestRetryInterval|60000|UINT32
> |0x00000034
> +
> + ## This value is the maximum retries of an IPMI SSIF response
> + # @Prompt Number of IPMI SSIF response retries.
> +
> gEfiMdePkgTokenSpaceGuid.PcdIpmiSsifResponseRetryCount|250|UINT8|0x0
> 0000035
> +
> + ## This is the required interval for each IPMI response retry.
> + # The IPMI specification specified min value is 60ms (section 12.17).
> + # @Prompt Time-out for a response, internal
> +
> gEfiMdePkgTokenSpaceGuid.PcdIpmiSsifResponseRetryInterval|60000|UINT3
> 2|0x00000036
> +
> [PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
> ## This value is used to set the base address of PCI express hierarchy.
> # @Prompt PCI Express Base Address.
> diff --git a/MdePkg/Include/IndustryStandard/IpmiSsif.h
> b/MdePkg/Include/IndustryStandard/IpmiSsif.h
> new file mode 100644
> index 000000000000..4a97438109a9
> --- /dev/null
> +++ b/MdePkg/Include/IndustryStandard/IpmiSsif.h
> @@ -0,0 +1,98 @@
> +/** @file
> + IPMI SSIF Definitions
> +
> + Copyright (c) 2023, Ampere Computing LLC. All rights reserved. 
> + SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> + @par Revision Reference:
> + - IPMI Specification
> + Version 2.0, Rev. 1.1
> +
> +
> https://www.intel.com/content/www/us/en/products/docs/servers/ipmi/ip
> mi-second-gen-interface-spec-v2-rev1-1.html
> +**/
> +
> +#ifndef IPMI_SSIF_H_
> +#define IPMI_SSIF_H_
> +
> +///
> +/// Definitions for SMBUS Commands for SSIF
> +/// Table 12 - Summary of SMBUS Commands for SSIF
> +///
> +
> +// Write block
> +#define IPMI_SSIF_SMBUS_CMD_SINGLE_PART_WRITE 0x02
> +#define IPMI_SSIF_SMBUS_CMD_MULTI_PART_WRITE_START 0x06
> +#define IPMI_SSIF_SMBUS_CMD_MULTI_PART_WRITE_MIDDLE 0x07
> +#define IPMI_SSIF_SMBUS_CMD_MULTI_PART_WRITE_END 0x08
> +
> +// Read block
> +#define IPMI_SSIF_SMBUS_CMD_SINGLE_PART_READ 0x03
> +#define IPMI_SSIF_SMBUS_CMD_MULTI_PART_READ_START 0x03
> +#define IPMI_SSIF_SMBUS_CMD_MULTI_PART_READ_MIDDLE 0x09
> +#define IPMI_SSIF_SMBUS_CMD_MULTI_PART_READ_END 0x09
> +#define IPMI_SSIF_SMBUS_CMD_MULTI_PART_READ_RETRY 0x0A
> +
> +///
> +/// Definitions for Multi-Part Read Transactions
> +/// Section 12.5
> +///
> +#define IPMI_SSIF_MULTI_PART_READ_START_SIZE 0x1E
> +#define IPMI_SSIF_MULTI_PART_READ_START_PATTERN1 0x00
> +#define IPMI_SSIF_MULTI_PART_READ_START_PATTERN2 0x01
> +#define IPMI_SSIF_MULTI_PART_READ_END_PATTERN 0xFF
> +
> +///
> +/// IPMI SSIF maximum message size
> +///
> +#define IPMI_SSIF_INPUT_MESSAGE_SIZE_MAX 0xFF
> +#define IPMI_SSIF_OUTPUT_MESSAGE_SIZE_MAX 0xFF
> +
> +///
> +/// IPMI SMBus system interface maximum packet size in byte
> +///
> +#define IPMI_SSIF_MAXIMUM_PACKET_SIZE_IN_BYTES 0x20
> +
> +typedef enum {
> + IpmiSsifPacketStart = 0,
> + IpmiSsifPacketMiddle,
> + IpmiSsifPacketEnd,
> + IpmiSsifPacketSingle,
> + IpmiSsifPacketMax
> +} IPMI_SSIF_PACKET_ATTRIBUTE;
> +
> +#pragma pack (1)
> +///
> +/// IPMI SSIF Interface Request Format
> +/// Section 12.2 and 12.3
> +///
> +typedef struct {
> + UINT8 NetFunc;
> + UINT8 Command;
> +} IPMI_SSIF_REQUEST_HEADER;
> +
> +///
> +/// IPMI SSIF Interface Response Format
> +/// Section 12.4 and 12.5
> +///
> +typedef struct {
> + UINT8 StartPattern[2];
> + UINT8 NetFunc;
> + UINT8 Command;
> +} IPMI_SSIF_RESPONSE_PACKET_START;
> +
> +typedef struct {
> + UINT8 BlockNumber;
> +} IPMI_SSIF_RESPONSE_PACKET_MIDDLE;
> +
> +typedef struct {
> + UINT8 EndPattern;
> +} IPMI_SSIF_RESPONSE_PACKET_END;
> +
> +typedef struct {
> + UINT8 NetFunc;
> + UINT8 Command;
> +} IPMI_SSIF_RESPONSE_SINGLE_PACKET;
> +
> +#pragma pack ()
> +
> +#endif /* IPMI_SSIF_H_ */
> --
> 2.40.0