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

[Romain Perier]

Hi,

no ideas ?

I can try another solution if you want.

Regards,

Romain


Le 09/01/2017 à 09:23, Romain Perier a écrit :
> Hi,
>
>
> Le 09/01/2017 à 08:20, Kever Yang a écrit :
>>
>> On 01/06/2017 06:52 PM, Romain Perier wrote:
>>> 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 ?
>>>>
>>
>> SPL load from sdcard/emmc and loaded via usb, one difference may be 
>> cpu frequency.
>>
>> I agree that the udelay() may not correct, could you help to do:
>> - delay 1 S or more with udelay(), then we can see if it's correct, I 
>> don't know how the udelay is implement on rk3288,
>>     if it's using ARM generic timer, then it's related to cpu frequency;
>> - using rockchip_udelay() instead of udelay(), this interface is 
>> using rktimer, it should be correct.
>
> I have just tried both solutions, unfortunately, it did not help (same 
> issues)
>
> Thanks,
> Romain
>