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AM3352: U-boot customization

Part Number: AM3352

#1. I would like to go through the uboot source code. where is the main function source file?

arch/arm/cpu/armv7/start.S

/*
* Setup vector:
* (OMAP4 spl TEXT_BASE is not 32 byte aligned.
* Continue to use ROM code vector only in OMAP4 spl)
*/
#if !(defined(CONFIG_OMAP44XX) && defined(CONFIG_SPL_BUILD))
/* Set V=0 in CP15 SCTLR register - for VBAR to point to vector */
mrc p15, 0, r0, c1, c0, 0 @ Read CP15 SCTLR Register
bic r0, #CR_V @ V = 0
mcr p15, 0, r0, c1, c0, 0 @ Write CP15 SCTLR Register

/* Set vector address in CP15 VBAR register */
ldr r0, =_start
mcr p15, 0, r0, c12, c0, 0 @Set VBAR
#endif

/* the mask ROM code should have PLL and others stable */
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
bl cpu_init_cp15
#ifndef CONFIG_SKIP_LOWLEVEL_INIT_ONLY
bl cpu_init_crit
#endif
#endif

bl _main

 

#2. Is there a poring guide as that of old SDK in below page? or Will it be updated according to new version Processor SDK?

 

#3. How to boot custom board with the default uboot, which function which macro definition to modify?

  • Hello Tony,

    Tony Tang said:
    #1. I would like to go through the uboot source code. where is the main function source file?

    You can follow the steps from this post to go through the U-Boot source code.


    Tony Tang said:
    #2. Is there a poring guide as that of old SDK in below page? or Will it be updated according to new version Processor SDK?

    Please, refer to this thread for board porting.


    Tony Tang said:
    #3. How to boot custom board with the default uboot, which function which macro definition to modify?

    First you will need to select the SYSBOOT settings, hardcode and skip the EEPROM checks, then setup your board's DDR timings. Depending on that you will need to change the appropriate macro definitions and device tree settings.

    Best regards,
    Kemal

  • Hello Tony,

    If you are done with this thread, please mark it as resolved.

    Best regards,
    Kemal