SPRAD09A December   2021  – July 2022 DRA821U , DRA821U-Q1

 

  1.   Abstract
  2.   Trademarks
  3. 1Hardware and Software Required Stuff
  4. 2DRA821U Boot Mode With Fast Boot Method
  5. 3Detailed Steps
    1. 3.1 Step1: Patch and Build/Copy the u-boot
    2. 3.2 Step2: Optimizations by Switching to xSPI Boot: Copy Bootloaders to xSPI
    3. 3.3 Step 3: Optimize the DTSI by Disabling Nodes not Mandatory for Linux Boot
    4. 3.4 Step 4: Create Bootable SD Card, Switch to TinyFS
    5. 3.5 Step 5: Switch to eMMC Filesystem
    6. 3.6 Step 6: Optimizations With Bootargs
    7. 3.7 Step 7: Hijack the init
  6. 4Debug Commands
    1. 4.1 SF Probe
    2. 4.2 mmcblk
    3. 4.3 How to Check Mounted Devices?
    4. 4.4 How to Check Your Partitions?
    5. 4.5 How to Restore Your Boot Setting?
  7. 5Fast Boot Result Review
  8. 6References
  9. 7Revision History

5 Fast Boot Result Review

This is the cold boot until the Kernel login, the cost time is about ~3 seconds.

From the log result in the following picture, we have (10.070 – 7.098) = 2.972 seconds.

Comparing the original Linux boot (2X~4X seconds), this fast boot result is good enough for automotive applications.

User can base on this to do those following developing:

  • Addon their DTSI devices.
  • Addon their application based on the tiny rootfs.
GUID-20211124-SS0I-4NFC-HMGT-6MRCBJKPSZCM-low.png Figure 5-1 Jacinto DRA821U Fast Boot Result