Re: [PATCH 6/6] ARM: imx: select ARM_CPU_SUSPEND when necessary

From: Arnd Bergmann <arnd@arndb.de>
To: Shawn Guo <shawn.guo@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org,
	Russell King <rmk+kernel@arm.linux.org.uk>,
	linux-kernel@vger.kernel.org, Eric Miao <eric.miao@linaro.org>,
	stable@vger.kernel.org
Subject: Re: [PATCH 6/6] ARM: imx: select ARM_CPU_SUSPEND when necessary
Date: Thu, 23 Aug 2012 14:20:50 +0000	[thread overview]
Message-ID: <201208231420.50247.arnd@arndb.de> (raw)
In-Reply-To: <20120823024119.GD24242@S2101-09.ap.freescale.net>

On Thursday 23 August 2012, Shawn Guo wrote:
> On Wed, Aug 22, 2012 at 05:13:10PM +0200, Arnd Bergmann wrote:
> > On i.MX6, we select ARM_CPU_SUSPEND when building with power management
> > support, but for some reason this was omitted on i.MX5. Normally we
> > build kernels for both together so the error only showed up in
> > randconfig tests.
> > 
> > Without this patch, building imx5 standalone results in:
> > 
> > arch/arm/mach-imx/built-in.o: In function `v7_cpu_resume':
> > arch/arm/mach-imx/head-v7.S:104: undefined reference to `cpu_resume'
> > 
> So far, none of the functions in head-v7.S is used on imx5.  Also
> since imx5 SoCs implement State Retention Power Gating in hardware,
> ARM_CPU_SUSPEND support will never be used on imx5.
> 
> Maybe we should make head-v7.S only compile for imx6?

In tegra and shmobile, the respective file is called headsmp.S, so
I would suggest we rename it to the same here and only build it when
CONFIG_SMP is set, which comes down to imx6 at the moment.

How is this version?

	Arnd

>From 4036e8f292887e7b1abc8eacec7d619abd608178 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Fri, 17 Aug 2012 00:16:08 +0000
Subject: [PATCH] ARM: imx: build i.MX6 functions only when needed

The head-v7.S contains a call to the generic cpu_suspend function,
which is only available when selected by the i.MX6 code. As
pointed out by Shawn Guo, i.MX does not actually use any
functions defined in head-v7.S. It is also needed only for
the i.MX6 power management code and for the SMP code, so
we can restrict building this file to situations in which
at least one of those two is present.

Finally, other platforms with a similar file call it headsmp.S,
so we can rename it to the same for consistency.

Without this patch, building imx5 standalone results in:

arch/arm/mach-imx/built-in.o: In function `v7_cpu_resume':
arch/arm/mach-imx/head-v7.S:104: undefined reference to `cpu_resume'

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Eric Miao <eric.miao@linaro.org>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: stable@vger.kernel.org

diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile
index e08adb7..d004d37 100644
--- a/arch/arm/mach-imx/Makefile
+++ b/arch/arm/mach-imx/Makefile
@@ -71,14 +71,13 @@ obj-$(CONFIG_DEBUG_LL) += lluart.o
 obj-$(CONFIG_HAVE_IMX_GPC) += gpc.o
 obj-$(CONFIG_HAVE_IMX_MMDC) += mmdc.o
 obj-$(CONFIG_HAVE_IMX_SRC) += src.o
-obj-$(CONFIG_CPU_V7) += head-v7.o
-AFLAGS_head-v7.o :=-Wa,-march=armv7-a
-obj-$(CONFIG_SMP) += platsmp.o
+AFLAGS_headsmp.o :=-Wa,-march=armv7-a
+obj-$(CONFIG_SMP) += headsmp.o platsmp.o
 obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o
 obj-$(CONFIG_SOC_IMX6Q) += clk-imx6q.o mach-imx6q.o
 
 ifeq ($(CONFIG_PM),y)
-obj-$(CONFIG_SOC_IMX6Q) += pm-imx6q.o
+obj-$(CONFIG_SOC_IMX6Q) += pm-imx6q.o headsmp.o
 endif
 
 # i.MX5 based machines
diff --git a/arch/arm/mach-imx/head-v7.S b/arch/arm/mach-imx/headsmp.S
similarity index 100%
rename from arch/arm/mach-imx/head-v7.S
rename to arch/arm/mach-imx/headsmp.S
