Re: [PATCH 1/3] ARM: OMAP2+: Fix realtime_counter_init warning in timer.c

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On Wednesday 28 November 2012 09:31 PM, Jon Hunter wrote:

On 11/28/2012 09:55 AM, Santosh Shilimkar wrote:
On Wednesday 28 November 2012 09:17 PM, Jon Hunter wrote:

On 11/28/2012 12:09 AM, Santosh Shilimkar wrote:
On Wednesday 28 November 2012 07:45 AM, Jon Hunter wrote:
In commit fa6d79d (ARM: OMAP: Add initialisation for the real-time
counter), the function realtime_counter_init() was added. However, if
the kernel configuration option CONFIG_SOC_OMAP5 is not selected then
the following compiler warning is observed.

     CC      arch/arm/mach-omap2/timer.o
     arch/arm/mach-omap2/timer.c:489:20: warning:
‘realtime_counter_init’
     defined but not used [-Wunused-function]

Commit fa6d79d also introduced the kernel configuration option
CONFIG_SOC_HAS_REALTIME_COUNTER. If this option is not selected then
the
a stub function for realtime_counter_init() is defined.

The option CONFIG_SOC_HAS_REALTIME_COUNTER and stub function are not
really needed because ...

1. For non-OMAP5 devices, there is no realtime counter and so
      realtime_counter_init() function is not used.
2. For OMAP5 devices, CONFIG_SOC_HAS_REALTIME_COUNTER is always
selected
      and cannot be disabled, so the stub function for
realtime_counter_init()
      is never used.

Fix this warning by removing the kernel configuration option
CONFIG_SOC_HAS_REALTIME_COUNTER and stub function, and only include
the function realtime_counter_init() if CONFIG_SOC_OMAP5 is selected.

Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx>

Reported-by: Tony Lindgren <tony@xxxxxxxxxxx>
Signed-off-by: Jon Hunter <jon-hunter@xxxxxx>
---
The #ifdef was avoided because the real-time counter can be used on
other future SOCs. And the those SOCs just select
SOC_HAS_REALTIME_COUNTER. And that stub was added because OMAP5 can
work without real-time counter configuration enabled using 32K counter.
But since we are any way have that SOC_HAS_REALTIME_COUNTER always
set for SOC which wants to use it, we can actually remove the stub
and hence avoid the warning. Let me know if below patch is ok
with you ? attached the same for mailer issues

  From e000aa13e47e29fbe3473bfd0277cb057c3160cc Mon Sep 17 00:00:00 2001
From: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
Date: Wed, 28 Nov 2012 11:28:57 +0530
Subject: [PATCH] ARM: OMAP2+: Fix realtime_counter_init warning in
timer.c
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

In commit fa6d79d (ARM: OMAP: Add initialisation for the real-time
counter), the function realtime_counter_init() was added. However, if
the kernel configuration option CONFIG_SOC_OMAP5 is not selected then
the following compiler warning is observed.

      CC      arch/arm/mach-omap2/timer.o
      arch/arm/mach-omap2/timer.c:489:20: warning:
‘realtime_counter_init’
      defined but not used [-Wunused-function]

It is because of the stub init function which was added for the cases
where realtime_counter_init() is called with
!CONFIG_SOC_HAS_REALTIME_COUNTER.
This is actually not necessary since the SOC which need this feature
will explicitly select the configuration.

So just drop the unused stub to avoid the build warning.

Patch is made after seeing Jon's patch which was wrapping the
real-time counter code under needed SOC #ifdef

Cc: Jon Hunter <jon-hunter@xxxxxx>

Reported-by: Tony Lindgren <tony@xxxxxxxxxxx>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
---
   arch/arm/mach-omap2/timer.c |    3 ---
   1 file changed, 3 deletions(-)

diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index 69e4663..79d8e6b 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -428,9 +428,6 @@ static void __init realtime_counter_init(void)

       iounmap(base);
   }
-#else
-static inline void __init realtime_counter_init(void)
-{}
   #endif

   #define OMAP_SYS_TIMER_INIT(name, clkev_nr, clkev_src,            \

Hi Santosh,

Thanks for the feedback. Unfortunately, the above is not enough. If I
disable SOC_OMAP5 and leave SOC_HAS_REALTIME_COUNTER enabled, then I
still see the warning message. So I could see that people could still
hit this with randconfig.

I did mention that but since OMAP5 selects the feature, I was thinking
it is fine.

Understand the desire to make this a selectable configuration, but given
to date only OMAP5 uses it, it was simpler and cleaner just to remove
the option. However, we could keep the option and just do something
like ...

diff --git a/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig
index 813c267..500f2f6 100644
--- a/arch/arm/mach-omap2/Kconfig
+++ b/arch/arm/mach-omap2/Kconfig
@@ -26,6 +26,8 @@ config SOC_HAS_OMAP2_SDRC

   config SOC_HAS_REALTIME_COUNTER
          bool "Real time free running counter"
+       depends on SOC_OMAP5
+       default y

   config ARCH_OMAP2
          bool "TI OMAP2"
@@ -79,7 +81,6 @@ config SOC_OMAP5
          select ARM_GIC
          select CPU_V7
          select HAVE_SMP
-       select SOC_HAS_REALTIME_COUNTER
          select COMMON_CLK

I have tested this and this resolves the warning.

Go ahead and fold above change on top of my patch which
drops the stub.

Well if we drop the stub then we cannot make it selectable for OMAP5. So
in other words folding the above change on top of your patch will still
not work ;-)

Oh yes.. Just ignore another follow up email which i sent thinking I
lost the connection in between.

The above patch will only allow you to use the REALTIME COUNTER on
OMAP5, but it makes it selectable and so the stub is needed now. If
future devices wish to use the REALTIME COUNTER then they can be added
to the "depends on" statement.

The above patch should be all we need.

I agree. Feel free to add my ack when you cook up the patch

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