Visible to Intel only — GUID: pmh1677546544751
Ixiasoft
Visible to Intel only — GUID: pmh1677546544751
Ixiasoft
A.2.2. HPS Use of SDM QSPI Controller Use Cases
On power up, the SDM owns the QSPI controller. In order for the HPS to use the QSPI controller, the HPS must request ownership from the SDM.
Once the HPS obtains ownership of the QSPI controller, it retains ownership until the next power cycle, cold reset, or an HPS reboot generated from an RSU event.
The following details the typical flow for the HPS to use the QSPI controller:
- The bootloader passes the value of the QSPI controller reference clock to the end application or operating system.
- The end application uses the QSPI controller.
For the Linux use case, the U-Boot passes the value of the QSPI reference clock into the Linux device tree. In the Remote System Update (RSU) flow, the U-Boot also patches the Linux device tree to create the first mtd partition in the flash device, starting at the location of the SPT0. This approach is done to minimize the risk of corruption of DCMF, DCIO, and factory image, which are located outside of this partition (below the SPT0).