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From: Sekhar Nori <nsekhar@ti.com>
To: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Will Deacon <will.deacon@arm.com>,
	Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>,
	"linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>,
	Russell King <linux@arm.linux.org.uk>,
	Vaibhav Bedia <vaibhav.bedia@ti.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] ARM: Update SMP_ON_UP code to detect A9MPCore with 1 CPU devices
Date: Fri, 23 Aug 2013 22:38:41 +0530	[thread overview]
Message-ID: <52179719.3080609@ti.com> (raw)
In-Reply-To: <520A3518.3030301@ti.com>

On 8/13/2013 7:01 PM, Santosh Shilimkar wrote:
> On Tuesday 13 August 2013 07:19 AM, Will Deacon wrote:
>> On Mon, Aug 12, 2013 at 07:34:13PM +0100, Santosh Shilimkar wrote:
>>> On Friday 02 August 2013 11:48 AM, Will Deacon wrote:
>>>> I think this an A9-specific register, which reads as 0 on UP A9 and reads as
>>>> some form of PERIPH_BASE for SMP parts. The issue I have is when PERIPH_BASE
>>>> is zero.
>>>>
>>> What do we do here ? Should we document this in the code and proceed ?
>>> Mostly there is no platform with PERIPH_BASE = 0, so its should be fine but
>>> I am open for any other alternative.
>>
>> The only other alternative I can think of is forcing people to have
>> CONFIG_SMP=n, but that blows away single zImage for your platform.
>>
> Yep which surely we don't want considering after so much effort we
> have it working first place. How about going ahead with assumption
> that PERIPH_BASE = 0 case doesn't work.

I must be missing something but why cannot we use the SCU configuration
register "CPU number" field to determine that its a UP? I do not have an
OMAP4 board, but on AM437x, it certainly indicates only CPU0 present.

Thanks,
Sekhar

WARNING: multiple messages have this Message-ID (diff)
From: nsekhar@ti.com (Sekhar Nori)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: Update SMP_ON_UP code to detect A9MPCore with 1 CPU devices
Date: Fri, 23 Aug 2013 22:38:41 +0530	[thread overview]
Message-ID: <52179719.3080609@ti.com> (raw)
In-Reply-To: <520A3518.3030301@ti.com>

On 8/13/2013 7:01 PM, Santosh Shilimkar wrote:
> On Tuesday 13 August 2013 07:19 AM, Will Deacon wrote:
>> On Mon, Aug 12, 2013 at 07:34:13PM +0100, Santosh Shilimkar wrote:
>>> On Friday 02 August 2013 11:48 AM, Will Deacon wrote:
>>>> I think this an A9-specific register, which reads as 0 on UP A9 and reads as
>>>> some form of PERIPH_BASE for SMP parts. The issue I have is when PERIPH_BASE
>>>> is zero.
>>>>
>>> What do we do here ? Should we document this in the code and proceed ?
>>> Mostly there is no platform with PERIPH_BASE = 0, so its should be fine but
>>> I am open for any other alternative.
>>
>> The only other alternative I can think of is forcing people to have
>> CONFIG_SMP=n, but that blows away single zImage for your platform.
>>
> Yep which surely we don't want considering after so much effort we
> have it working first place. How about going ahead with assumption
> that PERIPH_BASE = 0 case doesn't work.

I must be missing something but why cannot we use the SCU configuration
register "CPU number" field to determine that its a UP? I do not have an
OMAP4 board, but on AM437x, it certainly indicates only CPU0 present.

Thanks,
Sekhar

  reply	other threads:[~2013-08-23 17:09 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-01 18:17 [PATCH] ARM: Update SMP_ON_UP code to detect A9MPCore with 1 CPU devices Santosh Shilimkar
2013-08-01 18:17 ` Santosh Shilimkar
2013-08-02  9:53 ` Will Deacon
2013-08-02  9:53   ` Will Deacon
2013-08-02 12:32   ` Santosh Shilimkar
2013-08-02 12:32     ` Santosh Shilimkar
2013-08-02 14:18 ` Dave Martin
2013-08-02 14:18   ` Dave Martin
2013-08-02 15:18   ` Santosh Shilimkar
2013-08-02 15:18     ` Santosh Shilimkar
2013-08-02 14:45 ` Sudeep KarkadaNagesha
2013-08-02 14:45   ` Sudeep KarkadaNagesha
2013-08-02 15:22   ` Santosh Shilimkar
2013-08-02 15:22     ` Santosh Shilimkar
2013-08-02 15:45     ` Sudeep KarkadaNagesha
2013-08-02 15:45       ` Sudeep KarkadaNagesha
2013-08-02 15:48       ` Will Deacon
2013-08-02 15:48         ` Will Deacon
2013-08-12 18:34         ` Santosh Shilimkar
2013-08-12 18:34           ` Santosh Shilimkar
2013-08-13 11:19           ` Will Deacon
2013-08-13 11:19             ` Will Deacon
2013-08-13 13:31             ` Santosh Shilimkar
2013-08-13 13:31               ` Santosh Shilimkar
2013-08-23 17:08               ` Sekhar Nori [this message]
2013-08-23 17:08                 ` Sekhar Nori
2013-08-23 17:17                 ` Santosh Shilimkar
2013-08-23 17:17                   ` Santosh Shilimkar
2013-08-23 17:41                   ` Sekhar Nori
2013-08-23 17:41                     ` Sekhar Nori
2013-09-24 17:08               ` Will Deacon
2013-09-24 17:08                 ` Will Deacon
2013-09-24 17:43                 ` Santosh Shilimkar
2013-09-24 17:43                   ` Santosh Shilimkar

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