Hard Processor System Booting User Guide: Agilex™ 5 SoCs

ID 813762
Date 12/20/2024
Public
Document Table of Contents

2.1. Boot Flow Overview for FPGA Configuration First Mode

You can program the Agilex™ 5 SoC device to configure the FPGA first and then boot the HPS. In this mode the FPGA IO and FPGA fabric are configured first, then the HPS EMIF I/O is configured. Finally, the SDM loads the HPS FSBL into the On-Chip RAM and releases the HPS from reset, starting the HPS boot flow.

The FPGA Configuration First Mode flow is shown in the figure below, covering the time from power-on-reset (TPOR) to boot completion (TBoot_Complete).
Figure 1. Typical FPGA Configuration First Boot Flow
Table 2.  FPGA Configuration First StagesThe sections following this table describe each stage in more detail.
Time Boot Stage Device State

TPOR to T1

POR

Power-on reset

T1 to T2

Secure Device Manager (SDM)-Boot ROM

  1. SDM samples the MSEL pins to determine the configuration scheme and boot source.
  2. SDM establishes the device security level based on eFuse values.
  3. SDM initializes the device by reading the configuration firmware (initial part of the bitstream) from the boot source.
  4. SDM authenticates and decrypts the configuration firmware (this process occurs as necessary throughout the configuration).
  5. SDM starts executing the configuration firmware.

T2 to T3

SDM-configuration firmware

  1. SDM I/O are enabled.
  2. SDM configures the FPGA I/O and core (full configuration) and enables the rest of your configured SDM I/O.
  3. SDM loads the FSBL from the bitstream into HPS on-chip RAM.
  4. HPS boot core start executing FSBL code.
  5. SDM enables HPS SDRAM I/O and optionally enables HPS debug.
  6. FPGA is in user mode.
  7. HPS is released from reset. All non-boot cores are in a wait-for-interrupt (WFI) state.

T3 to T4

First-Stage Bootloader (FSBL)

  1. HPS verifies the FPGA is in user mode.
  2. The FSBL initializes the HPS, including the SDRAM.
  3. HPS loads SSBL into SDRAM.
  4. HPS peripheral I/O pin mux and buffers are configured. Clocks, resets, and bridges are also configured.
  5. HPS I/O peripherals are available.

T4 to T5

Second-Stage Bootloader (SSBL)

  1. HPS bootstrap completes.
  2. OS is loaded into SDRAM.

T5 to TBoot_Complete

Operating System (OS)

The OS boots and applications are scheduled for runtime launch.