BBB MMC / SD detection instability with U-Boot 2014.04 (CPU 1GHz)

[Sulev-Madis Silber (ketas)]

On 2014-05-22 14:46, SAITOU Toshihide wrote:
> In message: <CADH-AwGb36EUknNofdch1Q4Pn8GAN+Ep9SdiJ_f7Q2v9e4kW1g at mail.gmail.com>
>             Winston Smith <smith.winston.101 at gmail.com> writes:
>> On Wed, May 21, 2014 at 11:20 AM, SAITOU Toshihide <toshi at ruby.ocn.ne.jp> wrote:
>>> If abort like
>>>
>>>   musbotg0: TI AM335X USBSS v0.0.13
>>>   Fatal kernel mode data abort: 'External Non-Linefetch Abort (S)'
>>>   trapframe: 0xc0a2eb60
>>
>> I see this with the 1Ghz uboot, it occurs about 50% of the time, see:
>>
>> http://comments.gmane.org/gmane.os.freebsd.devel.arm/8200
> 
> Although it is an ad hoc workaround but ``usb start'' at u-boot command
> prompt (someone mentioned before) or add device_printf("!\n") before
> ``rev = USBSS_READ4(sc, USBSS_REVREG);'' in the musbotg_attach of
> am335x_usbss.c prevent this panic for me.
> 
> Anyway I understand my procedure is workaround, and is working by
> chance or side effect, but eMMC boot and 1000 MHz operation is fun.
> 


I wish I could get that working too... I tried to trace device detection
path in loader but only found that the problem must be in uboot. Since
loader is program that runs in uboot. At least now I know how that works
a bit more. But actual issue remains unresolved. What's weird is how I
actually boot from eMMC and it's present in uboot... Loader comes from
eMMC and then loader suddenly has no devices inside it. The hell is that.