Hard Processor System Booting User Guide: Agilex™ 5 SoCs

ID 813762
Date 8/23/2024
Public

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5.2. ATF Linux Boot

The following figure shows the overview of the HPS Boot Flow which is directly booting from ATF to the Linux* OS.

Figure 35. The ATF Linux* Boot Flow

The boot flow is described in steps below:

  1. The Configuration Management Firmware (CMF) running on the SDM loads the FSBL, which is ATF BL2, into HPS On-Chip RAM and then bring the HPS boot core out from reset.
  2. The ATF BL2 loads the SSBL and OS, which is ATF BL31 and Linux OS, into DDR.
  3. The ATF BL2 jumps to ATF BL31.
  4. The ATF BL31 sets up the GIC, EL3 environment, and initializes the PSCI services. PSCI services remain available to Linux.
  5. The ATF BL31 jumps to the Linux* OS.
Note: The Linux* OS can access the SDM FPGA features through ATF BL31 through the Arm* Secure Monitor Call (SMC).

For information on Exception Levels, refer to Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs.