ARM: OMAP5: fix build breakage due to SCU usage

Hi,

Cortex-A15 based OMAP5 does not use Snoop Control Unit(SCU)[1]. However, there is lot of code that is shared between Cortex-A9 based OMAP4 and OMAP5, hence functionality code is shared with runtime usage of SCU based on SoC worked on. However on building with OMAP5 only generates the following errors:
arch/arm/mach-omap2/built-in.o: In function `scu_gp_set':
arch/arm/mach-omap2/sleep44xx.S:132: undefined reference to scu_power_mode' arch/arm/mach-omap2/built-in.o: In function scu_gp_clear':
arch/arm/mach-omap2/sleep44xx.S:229: undefined reference to scu_power_mode' arch/arm/mach-omap2/built-in.o: In function omap4_smp_init_cpus':
arch/arm/mach-omap2/omap-smp.c:185: undefined reference to scu_get_core_count' arch/arm/mach-omap2/built-in.o: In function omap4_smp_prepare_cpus':
arch/arm/mach-omap2/omap-smp.c:211: undefined reference to `scu_enable'

This was attempted to be "fixed" in various attempts in the past [2] [3].

This series applies on top of the other fixes in discussion for linux-next [4] [5].

Based on:
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git next-20130626

Nishanth Menon (2):
ARM: OMAP4: sleep: build OMAP4 specific functions only for OMAP4
ARM: scu: provide inline dummy functions when SCU is not present

 arch/arm/include/asm/smp_scu.h  |   13 ++++++++++++-
 arch/arm/mach-omap2/sleep44xx.S |    6 +++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0407e/CHDFJICC.html
[2] https://patchwork.kernel.org/patch/2568091/
[3] http://marc.info/?t=137120115400001&r=1&w=2
[4] http://lists.infradead.org/pipermail/linux-arm-kernel/2013-June/178209.html
[5] https://patchwork.kernel.org/patch/2781471/

Regards,
Nishanth Menon

1.7.9.5

CPU sleep and resume functions for Cortex-A9 based OMAP4 and Cortex-A15 based OMAP5 are different. Hence, even though we reuse most of the remaining file as part of OMAP4/5 consolidation, build OMAP4 specific sleep/resume operations only for OMAP4. SCU is not used OMAP5.

This fixes the following build failure with OMAP5 only build:
arch/arm/mach-omap2/built-in.o: In function `scu_gp_set':
arch/arm/mach-omap2/sleep44xx.S:132: undefined reference to scu_power_mode' arch/arm/mach-omap2/built-in.o: In function scu_gp_clear':
arch/arm/mach-omap2/sleep44xx.S:229: undefined reference to `scu_power_mode'

---
 arch/arm/mach-omap2/sleep44xx.S |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

index 88ff83a..9086ce0 100644
@@ -34,6 +34,8 @@ ppa_zero_params:
 ppa_por_params:
 	.word		1, 0
 
+#ifdef CONFIG_ARCH_OMAP4
+
 /*
  * =============================
  * == CPU suspend finisher ==

@@ -326,7 +328,9 @@ skip_l2en:
 
 	b	cpu_resume			@ Jump to generic resume
 ENDPROC(omap4_cpu_resume)
-#endif
+#endif	/* CONFIG_ARCH_OMAP4 */
+
+#endif	/* defined(CONFIG_SMP) && defined(CONFIG_PM) */
 
 #ifndef CONFIG_OMAP4_ERRATA_I688
 ENTRY(omap_bus_sync)

1.7.9.5

On platforms such as Cortex-A15 based OMAP5, SCU is not used, however since much code is shared between Cortex-A9 based OMAP4 (which uses SCU) and OMAP5, It does help to have inline functions returning error values when SCU is not present on the platform.

arch/arm/mach-omap2/omap-smp.c which is common between OMAP4 and 5 handles the SCU usage only for OMAP4.

This fixes the following build failure with OMAP5 only build:
arch/arm/mach-omap2/built-in.o: In function `omap4_smp_init_cpus':
arch/arm/mach-omap2/omap-smp.c:185: undefined reference to scu_get_core_count' arch/arm/mach-omap2/built-in.o: In function omap4_smp_prepare_cpus':
arch/arm/mach-omap2/omap-smp.c:211: undefined reference to `scu_enable'

---
 arch/arm/include/asm/smp_scu.h |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

index 18d1693..433f9d9 100644
@@ -23,10 +23,21 @@ static inline unsigned long scu_a9_get_base(void)
 	return pa;
 }
 
+#ifdef CONFIG_HAVE_ARM_SCU
 unsigned int scu_get_core_count(void __iomem *);
 int scu_power_mode(void __iomem *, unsigned int);
+#else
+static inline unsigned int scu_get_core_count(void __iomem *scu_base)
+{
+	return 0;
+}
+static inline int scu_power_mode(void __iomem *scu_base, unsigned int mode)
+{
+	return -EINVAL;
+}
+#endif
 
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) && defined(CONFIG_HAVE_ARM_SCU)
 void scu_enable(void __iomem *scu_base);
 #else
 static inline void scu_enable(void __iomem *scu_base) {}

1.7.9.5

Tony,

Any chance of picking these up?

I see that next-20130701 is broke as well in an OMAP5 only build. beyond the fixes already merged in - the missing series seems to be the $subject series to allow an OMAP5 only build.

Regards,
Nishanth Menon

Thanks yes applying into omap-for-v3.11/fixes now that the pending branches have been merged.

Tony