Visible to Intel only — GUID: rdu1675368452568
Ixiasoft
Visible to Intel only — GUID: rdu1675368452568
Ixiasoft
4.3.5.3. TBU with Untranslated Interface
ACE-Lite protocol supports the untranslated interface for address translation. Address translation is the process of translating the input address to output address-based address mapping and memory attribute information that is held in translation tables.
The main two attributes in the untranslated interface are: Stream ID and Substream ID. The overall address translation in the TCU is shown in the following figure where these Stream and Substream IDs are used to generate final Physical Address (PA).
Untranslated interface signals are provided in the following table.
Signal |
Description |
---|---|
AxMMUSECSID |
Secure Stream Identifier: Single bit Secure or Nonsecure identifier.
|
AxMMUSID[15:0] |
Stream Identifier: Used to identify the stream |
AxMMUSSIDV |
Substream Identifier Valid: Indicates that the transaction has additional substream identifier.
|
AxMMUSSID[0:0] |
Substream Identifier: It is valid when AxMMUSSIDV is asserted. |
AxMMUATST |
Address Translated: It is used say the address has already undergone PCIe* ATS translation. |
Few restrictions on driving stream signals:
- For transactions that do not specify the a substream ID as indicated by AxMMUSSIDV deasserted:
- AxMMUSSID must be driven to all zero
- For transactions that are in a non-secure stream, as indicated by AxMMUSECSID deasserted:
- AxPROT[1] must be HIGH. Indicates the Non-secure transaction
- Different virtual functions, so that each virtual function can be given a separate stage 2 configuration
- Streams with different traffic properties or real-time requirements, so that the cache can be configured to consider this information
SubstreamID is not used for Agilex™ 5 as it is only to represent a process identifier which most of the devices do not use it.
StreamIDs in the system manager can be configured by the secured System Software. Device driver or software should not have any control to alter these values.
- Transaction with Secure StreamIDs are translated according to the configuration in the secure registers and memory tables.
- Transactions with Non-secure StreamIDs are translated according to the configuration in the Non-secure registers and memory tables.
- The Secure and Non-secure StreamIDs are not related to each other.