From: <Claudiu.Beznea@microchip.com>
To: <jonas@orbital-systems.com>
Cc: <alexander.stein@systec-electronic.com>,
<linux-kernel@vger.kernel.org>, <sre@kernel.org>,
<Nicolas.Ferre@microchip.com>, <alexandre.belloni@bootlin.com>,
<linux-pm@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] power: reset: at91-reset: enable I-cache for at91sam9260_reset
Date: Fri, 26 Oct 2018 11:05:30 +0000 [thread overview]
Message-ID: <f8ed781a-2ee7-9d0e-1220-b23ccf3fdbb2@microchip.com> (raw)
In-Reply-To: <CALDOjzhgqcx5XEWon9EQXEGxt9J280Z6AvuFQcBa=nh-9VA6PQ@mail.gmail.com>
On 19.10.2018 13:30, Jonas Danielsson wrote:
> On Wed, Oct 17, 2018 at 3:10 PM <Claudiu.Beznea@microchip.com> wrote:
>>
>>>
>>> We take the normal path of sys_reboot => kernel_restart => machine_restart ...
>>>
>>> I added code to print the c1 register in different paths. And I-cache
>>> is enabled.
>>> So now I am really confused about why the patch worked.
>>
>> Just saying... maybe your instructions add some delay on the execution path
>> and this is why it helps... try to access cp15 co-processor for read and
>> write back the value you read without actually to modify it, to see if this
>> could be the reason: e.g.:
>>
>> mrc p15, 0, r0, c1, c0, 0
>> orr r1, r1, #4096 // whatever is in r1, doesn't matter
>> mcr p15, 0, r0, c1, c0, 0
>>
>
> Yes, this also seems to work. I have over 100 reboots completed with this code.
> So what could be the issue here? It seem related to the powering down
> of the sdram at least.
I don't know what could be the issue here.
>
> This thread on the AT91SAM community deals with the same issue:
> http://www.at91.com/viewtopic.php?t=25830
> There the solution people chose was removing the SDRAM powering down.
> But that leaves one open to the cause of the errata.
>
> Do you have any thought on how to approach this?
For now, no. I didn't dug this issue.
Thank you,
Claudiu
>
>> Thank you,
>> Claudiu Beznea
>>
>
> Regards
> Jonas
>
>
>>>
>>>> Best regards,
>>>> Alexander
>>>
>>> Jonas
>>>
>>>>
>>>>
>>>>
>>>
>>>
>
>
>
next prev parent reply other threads:[~2018-10-26 11:05 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-07 12:57 [PATCH] power: reset: at91-reset: enable I-cache for at91sam9260_reset Jonas Danielsson
2018-10-16 13:30 ` Claudiu.Beznea
2018-10-16 14:15 ` Jonas Danielsson
2018-10-16 14:52 ` Alexander Stein
2018-10-17 12:17 ` Jonas Danielsson
2018-10-17 13:10 ` Claudiu.Beznea
2018-10-19 10:30 ` Jonas Danielsson
2018-10-26 11:05 ` Claudiu.Beznea [this message]
2018-10-16 14:03 ` Alexander Stein
2018-10-16 14:19 ` Jonas Danielsson
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