Re: [PATCH 7/9] ARM: OMAP4+: Move the CPU wakeup prepare code under smp_prepare_cpus()

From: Santosh Shilimkar <santosh.shilimkar@ti.com>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Kevin Hilman <khilman@linaro.org>,
	tony@atomide.com, linux-omap@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 7/9] ARM: OMAP4+: Move the CPU wakeup prepare code under smp_prepare_cpus()
Date: Thu, 28 Mar 2013 17:39:51 +0530	[thread overview]
Message-ID: <5154330F.8090908@ti.com> (raw)
In-Reply-To: <20130328120450.GU30923@n2100.arm.linux.org.uk>

On Thursday 28 March 2013 05:34 PM, Russell King - ARM Linux wrote:
> On Thu, Mar 28, 2013 at 03:28:12PM +0530, Santosh Shilimkar wrote:
>> On Thursday 28 March 2013 03:16 PM, Russell King - ARM Linux wrote:
>>> On Thu, Mar 28, 2013 at 12:34:50AM +0530, Santosh Shilimkar wrote:
>>>> On Thursday 28 March 2013 12:15 AM, Kevin Hilman wrote:
>>>>> Santosh Shilimkar <santosh.shilimkar@ti.com> writes:
>>>>>
>>>>>> Move the secondary CPU wakeup prepare code under smp_prepare_cpus(). 
>>>>>
>>>>> Why?
>>>>>
>>>> Because that code belongs to smp_prepare_cpus(). As I said
>>>> in earlier patches, it was remainder of the pen release code
>>>> which was borrowed from ARM code initially.
>>>
>>> What about hotplug after the system is suspended?  Is this setup
>>> preserved by the secure ROM?
>>>
>>> If not, it really needs to be part of the CPU bringup, not the
>>> boot-time-only preparation code.
>>>
>> Its already the case. Hotplug CPU restarts just like CPU bring-up.
>> Initial code, hotplug cpu and last cpu(suspend) were taking identical
>> path for the suspend wakeup. Later you suggested after the discussion
>> that hotplug CPU state need not be saved and can be restarted just like
>> the CPU bring-up path.
>>
>> So the current code follows above.
> 
> smp_prepare_cpus() doesn't get run apart from at initial boot.
> 
> So, I repeat my question: what restores OMAP_AUX_CORE_BOOT_1 after
> context loss?
> 
Sorry I missed your point. OMAP_AUX_CORE_BOOT_* registers
are maintained across power transitions.

Regards,
Santosh