[U-Boot] rockchip: rk3288: Possible regression in sdram setup

[Romain Perier]

Add Rockchip Engineers to Cc:


Le 06/01/2017 à 11:28, Romain Perier a écrit :
> 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
>
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