Visible to Intel only — GUID: wuf1508436206567
Ixiasoft
Visible to Intel only — GUID: wuf1508436206567
Ixiasoft
2.2.3. Single SDM Flash
The QSPI controller is shared between the SDM and the HPS and only one of these can access the QSPI device at a time. At power-up, the SDM receives access to the QSPI controller. If the HPS needs access to the QSPI flash device, it must request ownership from the SDM through the HPS-to-SDM mailbox.
Software running on the HPS, such as the FSBL, must request permission from the SDM to access the flash attached to the SDM. After the HPS gains ownership of the QSPI controller, it retains ownership until any of the following events occur:
- A power cycle
- A cold reset
- An HPS reboot generated for an RSU event
For more information, refer to Appendix A. Booting and Configuration in the Agilex™ 7 Hard Processor System Technical Reference Manual .
In the Quad SPI flash example, the SSBL, OS and file system reside in the Unsorted Block Image File System (UBIFS).