The Chip Data Files define everything we need to know about a chip type. Their purpose is to keep libhei agnostic to specific chip information. Required information includes:
__HEI_ENABLE_HW_WRITE is defined).File extensions are not required, but it is recommended to use the extension .cdb (chip data binary).
The following data will be defined at the very beginning of each Chip Data File:
| Bytes | Desc | Value/Example |
|---|---|---|
| 8 | chip data keyword | 0x4348495044415441 (ascii for "CHIPDATA") |
| 4 | chip model/level | Unique ID defined by data file owner |
| 1 | file version | Version 1 => 0x01, Version 2 => 0x02, etc. |
The user application will use the chip model/level ID to determine which Chip Data File(s) should be used for the chip(s) that exist in the user application's system.
Immediately following the metadata in section 1, there will be a list of all registers referenced by the isolation nodes for this chip starting with:
| Bytes | Desc | Value/Example |
|---|---|---|
| 4 | register keyword | 0x52454753 (ascii for "REGS") |
| 3 | # of registers | 0 is invalid |
Then, each register will start with:
| Bytes | Desc | Value/Example |
|---|---|---|
| 3 | register ID | Unique ID defined by data file owner |
| 1 | register type | See appendix for supported register types |
| 1 | attribute flags | For each bit 0:disabled and 1:enabled |
| 1 | # of address instances | 0 is invalid |
The register ID must be unique for all registers withing the Chip Data File.
Supported attribute flags (bits ordered 0-7, left to right): 0: When enabled, the register is readable. 1: When enabled, the register is writable. 2-7: Reserved (default disabled)
A register could have multiple instances within a chip, each with a different address. A common example is that the same register could exist for each core on a processor chip.
So, immdiately following a register's metadata there will be a list of all instance addresses for a register. Each instance will have the following:
| Bytes | Desc | Value/Example |
|---|---|---|
| 1 | instance # | Unique value within the register |
| * | address | The address size is defined by the register type |
Hardware errors will be reported via registers organized in a tree-like structure. Isolation of these errors will traverse the tree from a root node down to the actual bit that raised the attention.
Immediately following all of the metadata described in section 2:
| Bytes | Desc | Value/Example |
|---|---|---|
| 4 | isolation node keyword | 0x4e4f4445 (ascii for "NODE") |
| 2 | # of isolation nodes | 0 is invalid |
Then, each node will start the following data:
| Bytes | Desc | Value/Example |
|---|---|---|
| 2 | node ID | Unique ID defined by data file owner |
| 1 | register type | See appendix for supported types |
| 1 | # of node instances | 0 is invalid |
The node ID must be unique for all nodes within a Chip Data File.
IMPORTANT: All registers referenced in a node's isolation rules must be of the same register type expressed in this field. This will ensure there is no ambiguity when resolving the bitwise expressions in the isolation rules.
Much like a register, a node can have multiple instances. Each instance will have the following:
| Bytes | Desc | Value/Example |
|---|---|---|
| 1 | instance # | Unique value within the node |
| 1 | # of capture registers | |
| 1 | # of isolation rules | 0 is invalid |
| 1 | # of child nodes |
This list specifies which registers to capture and store for debugging purposes. It is suggested to at least capture all registers referenced in a node's rules, but it is not required and it is left up to the user application to decide which registers to capture, if any.
Each capture register will have the following metadata, if any exist, and will immediately following the metadata for each node instance.
| Bytes | Desc | Value/Example |
|---|---|---|
| 3 | register ID | See section 2 for details |
| 1 | register instance | See section 2 for details |
Each node instance will represent a register, or set of registers. The register(s) can be configured to represent one or more attention types. Therefore, the isolation rules are used to define how attentions are reported. Expressions (see appendix) will be used to perform bitwise operations on register values. Any bits set after the expressions have been resolved will indicate active attentions.
Each rule will have the following metadata and will immediately following the capture register metadata for a node instance, if any exists.
| Bytes | Desc | Value/Example |
|---|---|---|
| 1 | attention type | See appendix for supported attention types |
| * | rule expression | See expression definition in appendix |
Note that the size of the expression field is variable. See the appendix for details.
Any bits set after an isolation rule resolution represents an active attention. A child node should exist for any bits in the resolution that indicate the attention originated from another node.
The following metadata will exist for each child node associated with a node instance:
| Bytes | Desc | Value/Example |
|---|---|---|
| 1 | bit position within the resolution | See notes below |
| 2 | child node ID | See node metadata |
| 1 | child node instance | See node metadata |
Notes:
After all of the Isolation Nodes have been specified, there will be a short list of all the root nodes to each of the isolation trees. The metadata for this section starts with:
| Bytes | Desc | Value/Example |
|---|---|---|
| 4 | root isolation node keyword | 0x524f4f54 (ascii for "ROOT") |
| 1 | # of root nodes | 0 is invalid |
Each isolation tree will report attentions for a single attention type and there can only be one tree per attention type. Immediately following the above metadata will be the following for each root node:
| Bytes | Desc | Value/Example |
|---|---|---|
| 1 | attention type | See appendix for supported attention types |
| 2 | root node ID | See node ID description in section 3 |
| 1 | root node instance | See node instance description in section 3 |
Power Systems SCOM register
Power Systems Indirect SCOM register
| Value | Description |
|---|---|
| 1 | System checkstop hardware attention |
| 2 | Unit checkstop hardware attention |
| 3 | Recoverable hardware attention |
| 4 | SW or HW event requiring action by the service processor FW |
| 5 | SW or HW event requiring action by the host FW |
Expressions are used in various locations within a Chip Data File. They can be used to characterize operations carried out against registers and/or integer constants. For example, <some_register> & (0xffff << 16).
The first byte of every expression is the expression type. The data immediately following this field is dependent on the expression type.
This is a special expression that indicates the value of the target register should be used in this expression. Generally, this means reading the register value from hardware.
The following is the complete byte definition of the expression:
| Bytes | Description/Value |
|---|---|
| 1 | expression type = 0x01 |
| 3 | register ID, see section 2 for register details |
| 1 | register instance, see section 2 for register details |
As you can see, the register ID and instance can be used to find this register's metadata (e.g. the address) from the register lists (see section 2).
This simply contains an unsigned integer constant.
The following is the complete byte definition of the expression:
| Bytes | Description/Value |
|---|---|
| 1 | expression type = 0x02 |
| * | An unsigned integer constant (see note below) |
IMPORTANT: The size of the constant is determined by the register type specified by the containing node. See section 3 for node details.
These expressions will contain other expressions. Each sub-expression will always be resolved before handling the containing expression. For example, say we need to do something like:
REG_1 & ~REG_2 | CONST_1
Where REG_* are register reference expressions and CONST_* are integer constant expressions. Following standard C++ order of operations, that would be evaluate into an expression like:
OR( AND( REG_1, NOT(REG_2) ), CONST_1 )
Where the NOT will be evaluated first, then the AND, then finally the OR.
A bitwise AND operation (i.e. EXPR_1 & EXPR_2).
| Bytes | Description/Value |
|---|---|
| 1 | expression type = 0x10 |
| 1 | # of sub-expressions |
| * | all sub-expressions |
A bitwise OR operation (i.e. EXPR_1 | EXPR_2).
| Bytes | Description/Value |
|---|---|
| 1 | expression type = 0x11 |
| 1 | # of sub-expressions |
| * | all sub-expressions |
A bitwise NOT operation (i.e. ~EXPR).
| Bytes | Description/Value |
|---|---|
| 1 | expression type = 0x12 |
| * | sub-expression |
A left shift operation (i.e. EXPR << shift_value).
| Bytes | Description/Value |
|---|---|
| 1 | expression type = 0x13 |
| 1 | shift value |
| * | sub-expression |
A left shift operation (i.e. EXPR >> shift_value).
| Bytes | Description/Value |
|---|---|
| 1 | expression type = 0x14 |
| 1 | shift value |
| * | sub-expression |