SPRZ455D december 2020 – june 2023 DRA829J , DRA829J-Q1 , DRA829V , DRA829V-Q1 , TDA4VM , TDA4VM-Q1
ADVANCE INFORMATION
UDMAP: Packet Mode Descriptor Address Space Select Field Restrictions
The UDMAP is used to perform several different types of data transfer including block copy and packet mode.
Packet mode transfers are designed to be used when the application requires support for true, unlimited fragment count scatter/gather type operations.
The Address Space Select field of the packet descriptor is used by the infrastructure as an identifier for which address space this particular memory region is located within. Address space 0 is the default unified address space for a given device. Address spaces 1-15 are used for alternate address maps which may be external to the device (PCIe/Hyperlink) or in other ‘tiles’ on large devices.
SW is recommended to avoid non-zero Address Space Select values in the descriptors used in packet mode transfers only. Block copy and other transfer types supported by UDMAP are unaffected.
Use of non-zero Address Space Select values in packet mode transfers can result in unintended memory accesses.
SW is recommended to avoid non-zero Address Space Select values in the descriptors used in packet mode transfers.
Use of non-zero Address Space Select values in packet mode transfers can result in unintended memory accesses.