This application brief provides the details of possible optimizations on TDA4x devices following SPL bootflow.

Currently, on K3 architecture-based devices, the boot architecture is designed as follows:

R5 SPL -> ATF -> OPTEE -> A72 SPL -> U-BOOT -> Kernel

Figure 1 Normal Boot Flow

Figure 2 Image Format (Normal Boot Flow)

ROM supports boot only via MCU(R5). This means that the bootloader has to run on the R5 core. However, keeping faster boot time in mind, the semi-falcon boot mode or falcon boot mode can be utilized.

Semi-Falcon Boot Flow

Semi-Falcon Boot is used to significantly speed up embedded system startup by having the R5 Secondary Program Loader (R5 SPL) load the u-boot image to A core directly, bypassing the Axx Core Secondary Program Loader. This thus prevents the overhead caused by loading and executing the A Core Secondary Program Loader.

The semi falcon boot flow is as follows:

R5 SPL -> ATF -> OPTEE -> -> U-BOOT -> Kernel

Figure 3 Semi-Falcon Boot Flow

Figure 4 Image Format(Semi-Falcon Boot Flow)

Methodology

To enable semi falcon boot mode, the following steps were followed:

1. Removed SPL running on A core from the tispl.bin binary.
2. Packaged u-boot binary in the same location where A core SPL was present in the tispl.bin binary earlier.
3. Changed the config ('CONFIG_TEXT_BASE') present in 'A' core defconfig to point to the location where 'A' core SPL was loaded earlier.

Perfomance improvement

• SDK: J784S4 LINUX SDK 11_00_00_08
• Filesystem: tisdk-adas-image-j784s4-evm.rootfs.tar.xz
• Boot media : SD CARD

 Normal: 8.448ms(upto Starting kernel ...print)

 Semi-falcon : 8.176ms(upto Starting kernel ...print)

FAQs

The following FAQ contains the patches required to enable this feature across Jacinto SoCs.

[FAQ] DRA821: SPL BOOT without A72 SPL on J7200 on 10.1 SDK - Processors forum - Processors - TI E2E support forums

Falcon Boot Flow

Falcon Boot is used to significantly speed up embedded system startup by having the Secondary Program Loader (SPL) load the kernel directly, bypassing the full U-Boot bootloader.

The falcon boot flow is as follows:

R5 SPL -> ATF -> OPTEE -> Kernel

Figure 5 Falcon Boot Flow

Figure 6 Image Format (Falcon Boot Flow)

Performance Improvement

• SDK: J784S4 LINUX SDK 11_02_00_02
• Filesystem: tisdk-adas-image-j784s4-evm.rootfs.tar.xz
• Boot media : SD CARD

Normal : 8.272 sec (upto Starting kernel ...print)

Falcon : 2.7sec (upto Starting kernel ...print)

FAQ

The following FAQ contains the patches required to enable this feature across Jacinto SoCs.

FAQ

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