Hello,
I have a strange behaviour with the SPL on rk3288.
When I build u-boot-rockchip master for the rock2 (rock2_defconfig), I can easily start u-boot SPL and u-boot from an sdcard (the emmc boot partition is erased so my board starts in maskrom mode by default) without any issues.
Now, I load uboot SPL and uboot over usb:
- I power up the board
- I generate an image for the bootrom:
# tools/mkimage -n rk3288 -T rkimage -d spl/u-boot-spl-dtb.bin out
- I uploaded this image via usb to the board
# cat out | openssl rc4 -K 7c4e0304550509072d2c7b38170d1711 | ../tools/rkflashtool/rkflashtool l
I get no output from the SPL. I have investigated and found that it is caused by sdram_rk3288.c: sdram_init(). More especially by the function phy_pctrl_reset(). I enabled EARLY_UART and added 2 printascii() in this function. This functions hangs in the second for loop. I hacked this function locally, I reduce the number of iterations from 4 to 3 then I added 2 uart outputs to this function and "OH!": it works, I get the following output:
pctrl_reset:for pctrl_reset:end for pctrl_reset:for pctrl_reset:end for
U-Boot SPL 2016.11-08675-ga4ae4ddda3-dirty (Jan 06 2017 - 10:35:41)
Now, if I remove my printascii() functions completly, it's no longer working. Which suggests that it might have something to do with busy wait delays... (I could be wrong)
From the sdram setup point of view, I don't see a real difference between an SPL loaded from sdcard and an SPL loaded via usb.
Rockchip guys: Would you have an idea about the problem ?
Thanks,
Regards,
Romain