Re: [PATCH 0/5] ARM: Centralize the access to the SCU register

From: Gregory CLEMENT <gregory.clement@free-electrons.com>
To: Rob Herring <robherring2@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
	Andrew Lunn <andrew@lunn.ch>,
	Russell King <linux@arm.linux.org.uk>,
	Jason Cooper <jason@lakedaemon.net>,
	Tawfik Bayouk <tawfik@marvell.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Nadav Haklai <nadavh@marvell.com>,
	Lior Amsalem <alior@marvell.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	Sascha Hauer <kernel@pengutronix.de>,
	Ezequiel Garcia <ezequiel.garcia@free-electrons.com>,
	Shawn Guo <shawn.guo@freescale.com>,
	Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Subject: Re: [PATCH 0/5] ARM: Centralize the access to the SCU register
Date: Fri, 27 Jun 2014 01:01:03 +0200	[thread overview]
Message-ID: <53ACA62F.1090802@free-electrons.com> (raw)
In-Reply-To: <CAL_JsqL9w0oxxM0zTAVioh0Uf3PNO3TfhxzOLV6KhBOoS4Fdiw@mail.gmail.com>

On 27/06/2014 00:56, Rob Herring wrote:
> On Thu, Jun 26, 2014 at 5:43 PM, Gregory CLEMENT
> <gregory.clement@free-electrons.com> wrote:
>> Hello,
>>
>> Following the feedback I go on the patch "ARM: mvebu: Enable SCU
>> Speculative linefills to L2 for Armada 375/38x" :
>> http://thread.gmane.org/gmane.linux.ports.arm.kernel/335961/focus=335993
>>
>> I take the opportunity of adding new functions in smp_scu.c to
>> centralize the other access done on the SCU register from C file in
>> this file.
>>
>> The first patch is a preliminary clean-up in smp_scu.c.
>>
>> The second and the third patches add functions to manipulate the SCU
>> control register.
>>
>> The forth patch use the new scu_spec_linefills_enable()
>> function. Enabling SCU Speculative linefills to L2 for Armada 375/38x
>> was the reason of this series.
>>
>> The last patch removed a direct access to the SCU register by an
>> access through the new scu_standby_enable() function. For this one I
>> have just checked that the kernel can be built using the
>> imx_v6_v7_defconfig config, but I didn't test it on an imx6 hardware.
> 
> Why would we not just turn on these 2 features unconditionally? If we

You mean in scu_enbale() ?

> don't know of any platform where they are broken, then we should just

At least on some imx6 SCU standby is broken according to the code and
the comments.

> enable them. We can add these functions only if necessary later.
> 
> Rob
> 
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> 

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com