[U-Boot] am3517: segmentation fault in Linux after upgrading from arago src to mainline u-boot

[Yegor Yefremov]

On Fri, Dec 6, 2013 at 8:28 AM, Yegor Yefremov
<yegorslists at googlemail.com> wrote:
> On Thu, Dec 5, 2013 at 6:28 PM, Måns Rullgård <mans at mansr.com> wrote:
>> Yegor Yefremov <yegorslists at googlemail.com> writes:
>>
>>> On Thu, Nov 28, 2013 at 5:57 PM, Tom Rini <trini at ti.com> wrote:
>>>> On Thu, Nov 28, 2013 at 05:39:09PM +0100, Yegor Yefremov wrote:
>>>>
>>>>> I'm having problems with the new u-boot (November 2013) and am3517
>>>>> SoC. When I start Debian 7.0 armhf I get lots of Segmentation faults,
>>>>> I can't even perform apt-get udpate. With the older u-boot (arago
>>>>> sources from 2010) everything seems to work properly.
>>>>>
>>>>> I've checked ATAG_MEM and both u-boot versions deliver same RAM start
>>>>> address and size. I've compared EMIF4 settings
>>>>> (arch/arm/cpu/armv7/omap3/emif4.c) and PINMUX and everything is the
>>>>> same.
>>>>>
>>>>> Where else can I look for differences?
>>>>
>>>> Can you bisect the arago tree from what it's based on, to what the top
>>>> of tree is there?  Some errata or another being patched up I guess..
>>>
>>> I've compared the x-loader's init routine with the one from SPL. An
>>> found this workaround in the mainline U-Boot
>>> (arch/arm/cpu/armv7/omap3/board.c):
>>>
>>> static void omap3_setup_aux_cr(void)
>>> {
>>>         /* Workaround for Cortex-A8 errata: #454179 #430973
>>>          *      Set "IBE" bit
>>>          *      Set "Disable Branch Size Mispredicts" bit
>>>          * Workaround for erratum #621766
>>>          *      Enable L1NEON bit
>>>          * ACR |= (IBE | DBSM | L1NEON) => ACR |= 0xE0
>>>          */
>>>         omap3_update_aux_cr_secure(0xE0, 0);
>>> }
>>>
>>> After commenting this routine and I don't see any segmentation faults
>>> during apt usage.
>>
>> On an r1pX Cortex-A8 (as found in the 35xx chips) you absolutely want
>> those bits set, especially if you're running Thumb2 code.  Otherwise you
>> will get random crashes.
>
> Where can I find info, if am3517 is r1pX? I've looked through "AM35x
> ARM Microprocessor: Technical Reference Manual", but found nothing
> similar.

This info was in the Errata.pdf:

AM3517AZCN i.e. silicon revision 1.1 (r1p7 ROM 15:58)

Yegor