Message-ID: <55D394C8.7070605@ti.com>
Date: Tue, 18 Aug 2015 16:25:44 -0400
From: Murali Karicheri <m-karicheri2@ti.com>
Organization: Texas Instruments
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To: Russell King - ARM Linux <linux@arm.linux.org.uk>,
        "santosh.shilimkar@oracle.com" <santosh.shilimkar@oracle.com>
CC: <ssantosh@kernel.org>, <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] ARM: keystone: add a work around to handle asynchronous
 external abort
References: <1439320409-20084-1-git-send-email-m-karicheri2@ti.com> <55CDF579.4050408@ti.com> <20150814140934.GX7557@n2100.arm.linux.org.uk> <55CE05EC.4040909@oracle.com> <55CE633C.10402@ti.com> <20150814215617.GA7557@n2100.arm.linux.org.uk> <55D25C64.3090107@ti.com> <55D2A1DD.9000007@oracle.com> <20150818081334.GK7557@n2100.arm.linux.org.uk>
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Russell,

On 08/18/2015 04:13 AM, Russell King - ARM Linux wrote:
> On Mon, Aug 17, 2015 at 08:09:17PM -0700, santosh.shilimkar@oracle.com wrote:
>>  From the logs this seems to be mostly clock related issue for some
>> peripheral. If the bootloader clock enable all hack still exists,
>> may be you can try that out.
>>
>> Another way to debug this is to start disabling peripheral drivers
>> from the kernel 1 by 1 and see if the issue goes away.
>
> Highly unlikely to make any difference.  As the failure happens soo early
> with the patch applied, the kernel hasn't had much of a chance to touch
> the hardware - about the only things are the decompressor and the kernel
> touching the early console.  As they seem to be working, it suggests
> that's not the cause.
>
> It seems to be pointing towards something in the boot loader...
>
> Normally, uboot will hook itself into the vectors to report errors, but
> I wonder whether uboot enables asynchronous aborts while it's running.
> Don't forget to make sure that the aborts are disabled again prior to
> calling the kernel.
>
Thanks for your input.

The patch works now once I move the local_abort_enable() to later just 
before calling reserve_crashkernel() in setup_arch(). The abort handler 
gets called right after enabling it which means it has happened even 
before reaching here.

I have added the abort handler to u-boot code and I get the same abort 
which means the root cause is u-boot or ROM boot loader. I would try to 
debug if root cause is u-boot. If it is ROM boot loader, I will have to 
add a work around in u-boot or Linux. Is there a preference of one over 
the other? The exception handling in u-boot is premature and will 
require more work to add a work around. Is there still a possibility of 
adding the work around in Linux?

-- 
Murali Karicheri
Linux Kernel, Keystone
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