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I have a customized imx6 solo board. 1 GB of DDR3 ram and MMC for boot.

I have ported u-boot(the fslc community one) and it seems to work fine. I also run stress RAM test and it came out OK. (calibration data is used in imximage.cfg)

when I attempt to run kernel it stuck at "starting kernel" commands:

>>ext4load mmc 0 ${loadaddr} zImage
>>ext4load mmc 0 ${fdt_addr} *.dtb
>>bootz ${loadaddr} - ${fdt_addr}

(loadaddr=0x12000000 and fdt_addr=0x18000000 the bootargs has the right ttymxc and baudrate value)

with early printk it says: "Uncompressing Linux... done, booting the kernel"

printk doesn't work, (Guess the initialize not done). fortunatly, I have some LEDs on board, so I tried to use them and trace the code. the it seems it kernel hangs at enabling MMU:

/arch/arm/kernel/head.S :

.
.
    ENTRY(__turn_mmu_on)
        mov r0, r0
        instr_sync
        mcr p15, 0, r0, c1, c0, 0
        mrc p15, 0, r3, c0, c0, 0
        instr_sync
        mov r3, r3
        mov r3, r13
        ret r3
    __turn_on_mmu_end
    ENDPROC(__turn_mmu_on)`enter code here`
...

those mcr and mrc are the point that i can toggle GPIObefore them and not after!

I should add: to toggling GPIO I used physical address before them and virtual address after.(I also test with physical add) physical address: for example 0x0209c000 -> gpio data register which virtual address is: 0xf429c000 (just in iMX platform)

also I disable i/d cache before boot up kernel. didn't know how to disable MMU but according the u-boot it seems to be disabled.

please help me find the solution. thanks Vahid

V Gharaee
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  • *"with early printk it says: "Uncompressing Linux... done, booting the kernel""* -- That makes no sense. The verbose uncompressing messages are from **decompress_kernel()** in **arch/arm/boot/compressed/misc.c**, and has nothing to do with the **earlyprintk** feature. Is your kernel even built with **CONFIG_EARLY_PRINTK** enabled, and is it properly enabled in the the kernel command line? – sawdust Feb 25 '19 at 08:02
  • without LL_debug and earlyprintk it just says: "Starting kernell ..." – V Gharaee Feb 25 '19 at 08:25
  • the kernel command line is complete. – V Gharaee Feb 25 '19 at 08:25

0 Answers0