srvgrp-ras-agent.adoc

Service Group - RAS_AGENT (SERVICEGROUP_ID: 0x000B)

The RAS_AGENT service group provides services to enumerate various error sources in a system and to retrieve their descriptors.

Each error source in a system is assigned a unique 32-bit identification number, referred to as RAS_ERR_SRC_ID.

The following table lists the services in the RAS_AGENT service group:

Table 1. RAS Agent Services

Service ID	Service Name	Request Type
0x01	RAS_ENABLE_NOTIFICATION	NORMAL_REQUEST
0x02	RAS_GET_NUM_ERR_SRCS	NORMAL_REQUEST
0x03	RAS_GET_ERR_SRCS_ID_LIST	NORMAL_REQUEST
0x04	RAS_GET_ERR_SRC_DESC	NORMAL_REQUEST

Error Source Descriptor Format

ACPI Systems

For systems that support ACPI/APEI, the format of the error source descriptor is as defined in ACPI specification v6.4 or above, (GHESv2) cite:[ACPI]. If the value of RAS_GET_ERR_SRC_DESC.FLAGS[3:0] is 0, it indicates that the error source descriptor format is GHESv2.

The RAS agent populates the error source descriptor fields according to the error source specified by RAS_ERR_SRC_ID.

Note

The error source descriptor has an error_status_structure field which is a generic address structure (GAS) as defined in ACPI v6.4 (GHESv2) cite:[ACPI]. This field specifies the location of a register that contains the physical address of a block of memory that holds the error status data for the specified error source. This block of memory is referred to as error_status_block. The allocation of error_status_block is platform dependent and is done by the RAS agent. The physical address of error_status_block is stored in the error_status_structure field of the error source descriptor being returned.

Non-ACPI Systems

RAS is not standardized for non-ACPI systems. Such systems may define custom format for an error source descriptor. The type of custom error source descriptor format can be read from RAS_GET_ERR_SRC_DESC.FLAGS[3:0]. The values from 1 to 15 are reserved for the custom format types.

Notifications

This service group does not support any events for notification.

Service: RAS_ENABLE_NOTIFICATION (SERVICE_ID: 0x01)

This service allows the application processor to subscribe to RAS_AGENT service group notifications. The platform may optionally support notifications for events that may occur. The platform microcontroller can send these notification messages to the application processor if they are implemented and the application processor has subscribed to them. The supported events are described in Notifications.

Table 2. Request Data

Word	Name	Type	Description
0	EVENT_ID	uint32	The event to be subscribed for notification.
1	REQ_STATE	uint32	Requested event notification state Change or query the current state of EVENT_ID notification. 0: Disable 1: Enable 2: Return current state. Any other values of REQ_STATE field other than the defined ones are reserved for future use.

Table 3. Response Data

Word	Name	Type	Description
0	STATUS	int32	Return error code Error Code Description RPMI_SUCCESS Event is subscribed successfully. RPMI_ERR_INVALID_PARAM EVENT_ID or REQ_STATE is invalid. RPMI_ERR_NOT_SUPPORTED Notification is not supported. Other errors [table_error_codes]
1	CURRENT_STATE	uint32	Current EVENT_ID notification state 0: Notification is disabled 1: Notification is enabled. In case of REQ_STATE = 0 or 1, the CURRENT_STATE will return the requested state. In case of an error, the value of CURRENT_STATE is unspecified.

Service: RAS_GET_NUM_ERR_SRCS (SERVICE_ID: 0x02)

This service queries number of error sources available in the system.

Table 4. Request Data

NA

Table 5. Response Data

Word	Name	Type	Description
0	STATUS	int32	Return error code Error Code Description RPMI_SUCCESS Service completed successfully and number of error sources returned as NUM_ERR_SRCS. Other errors [table_error_codes]
1	NUM_ERR_SRCS	uint32	Number of error sources.

Service: RAS_GET_ERR_SRCS_ID_LIST (SERVICE_ID: 0x03)

This service returns a list of RAS_ERR_SRC_ID for all error sources present in the system. The RAS_ERR_SRC_ID can be used to get the associated descriptor of the error source.

Table 6. Request Data

Word	Name	Type	Description
0	START_INDEX	uint32	Starting index of RAS_ERR_SRC_ID list. 0 for the first call, subsequent calls will use the next index of the remaining items.

Table 7. Response Data

Word	Name	Type	Description
0	STATUS	int32	Return error code Error Code Description RPMI_SUCCESS Service completed successfully and list of error sources returned. RPMI_ERR_INVALID_PARAM START_INDEX is invalid. Other errors [table_error_codes]
1	FLAGS	uint32	Reserved and must be 0.
2	REMAINING	uint32	Remaining number of error source IDs.
3	RETURNED	uint32	Number of error source IDs returned in this request.
4	RAS_ERR_SRC_ID[N]	uint32	An array of error source IDs where each entry in the array is a unique error source ID. N is equal to RETURNED number of error source IDs in this request.

Service: RAS_GET_ERR_SRC_DESC (SERVICE_ID: 0x04)

This service retrieves the error source descriptor of an error source specified by RAS_ERR_SRC_ID.

Word	Name	Type	Description
0	RAS_ERR_SRC_ID	uint32	Error source ID for which attributes are to be returned.
1	BYTE_OFFSET	uint32	Offset from which the descriptor is to be read. Offset 0 for the first call, subsequent byte offset of the remaining bytes.

Table 8. Response Data

Word	Name	Type	Description
0	STATUS	int32	Return error code Error Code Description RPMI_SUCCESS Service completed successfully and partial/complete error source descriptor returned. RPMI_ERR_INVALID_PARAM RAS_ERR_SRC_ID or BYTE_OFFSET is invalid. Other errors [table_error_codes]
1	FLAGS	uint32	Bits Description [31:4] Reserved and must be 0. [3:0] Format of the error source descriptor. Value 0 indicates that the error source descriptor is in GHESv2 format. Rest of the values from 1 to 15 are implementation specific.
2	REMAINING	uint32	Remaining number of bytes to be read.
3	RETURNED	uint32	Number of bytes read in this request.
4	ERR_SRC_DESC[N]	uint8	Full or partial descriptor N is equal to the RETURNED bytes in this request.