[RFC PATCH 0/6] ARM: cpuhotplug: move common functions to core

[RFC PATCH 0/6] ARM: cpuhotplug: move common functions to core

[Sanjay Singh Rawat]

Various SoCs with arm processors define their own platform hotplug related
functions. These functions can be defined as part of the core cpu hotplug
functions, this will avoid the duplication. This patchset is intended to
address this issue.

This patchset covers arm-Cortex-A9 of exynos, imx, realview, spear and
vexpress SoCs. Not having h/w, the patch is not tested.

Sanjay Singh Rawat (6):
  ARM: cpuhotplug: move common hotplug related functions to core
  ARM: imx: use the core cpu hotplug functions
  ARM: RealView: use the core cpu hotplug functions
  ARM: spear: use the core cpu hotplug functions
  ARM: vexpress: use the core cpu hotplug functions
  ARM: EXYNOS: use the core cpu hotplug functions

 arch/arm/include/asm/hotplug.h   |   24 ++++++++++++++
 arch/arm/kernel/Makefile         |    1 +
 arch/arm/kernel/cpuhotplug.c     |   64 ++++++++++++++++++++++++++++++++++++++
 arch/arm/mach-exynos/hotplug.c   |   40 ++----------------------
 arch/arm/mach-imx/hotplug.c      |   22 +------------
 arch/arm/mach-realview/hotplug.c |   37 +---------------------
 arch/arm/mach-spear/hotplug.c    |   37 +---------------------
 arch/arm/mach-vexpress/hotplug.c |   38 +---------------------
 8 files changed, 95 insertions(+), 168 deletions(-)
 create mode 100644 arch/arm/include/asm/hotplug.h
 create mode 100644 arch/arm/kernel/cpuhotplug.c

-- 
1.7.9.5

[RFC PATCH 1/6] ARM: cpuhotplug: move common hotplug related functions to core

[Sanjay Singh Rawat]

Add function which prepare arm processors to enter the low power for hotplug
functionality and handle the return path.

Signed-off-by: Sanjay Singh Rawat <sanjay.rawat@linaro.org>
---
 arch/arm/include/asm/hotplug.h |   24 +++++++++++++++
 arch/arm/kernel/Makefile       |    1 +
 arch/arm/kernel/cpuhotplug.c   |   64 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 89 insertions(+)
 create mode 100644 arch/arm/include/asm/hotplug.h
 create mode 100644 arch/arm/kernel/cpuhotplug.c

diff --git a/arch/arm/include/asm/hotplug.h b/arch/arm/include/asm/hotplug.h
new file mode 100644
index 0000000..ae80f0e
--- /dev/null
+++ b/arch/arm/include/asm/hotplug.h
@@ -0,0 +1,24 @@
+/*
+ * arch/arm/include/asm/hotplug.h
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+extern inline void cpu_enter_lowpower(void);
+extern inline void cpu_leave_lowpower(void);
+
+#else
+static inline void cpu_enter_lowpower(void)
+{
+	return -ENODEV;
+}
+static inline void cpu_leave_lowpower(void)
+{
+	return -ENODEV;
+}
+
+#endif
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 5f3338e..9bd370b 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_ISA_DMA)		+= dma-isa.o
 obj-$(CONFIG_PCI)		+= bios32.o isa.o
 obj-$(CONFIG_ARM_CPU_SUSPEND)	+= sleep.o suspend.o
 obj-$(CONFIG_SMP)		+= smp.o smp_tlb.o
+obj-$(CONFIG_HOTPLUG_CPU)	+= cpuhotplug.o
 obj-$(CONFIG_HAVE_ARM_SCU)	+= smp_scu.o
 obj-$(CONFIG_HAVE_ARM_TWD)	+= smp_twd.o
 obj-$(CONFIG_ARM_ARCH_TIMER)	+= arch_timer.o
diff --git a/arch/arm/kernel/cpuhotplug.c b/arch/arm/kernel/cpuhotplug.c
new file mode 100644
index 0000000..8651b96
--- /dev/null
+++ b/arch/arm/kernel/cpuhotplug.c
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2002 ARM Ltd.
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <asm/cp15.h>
+
+/*
+ * For Cortex-A9 processor
+ */
+static inline void ca9_enter_lowpower(void)
+{
+	unsigned int v;
+
+	asm volatile(
+	"	mcr	p15, 0, %1, c7, c5, 0\n"
+	"	mcr	p15, 0, %1, c7, c10, 4\n"
+	/*
+	 * Turn off coherency
+	 */
+	"	mrc	p15, 0, %0, c1, c0, 1\n"
+	"	bic	%0, %0, %3\n"
+	"	mcr	p15, 0, %0, c1, c0, 1\n"
+	"	mrc	p15, 0, %0, c1, c0, 0\n"
+	"	bic	%0, %0, %2\n"
+	"	mcr	p15, 0, %0, c1, c0, 0\n"
+	  : "=&r" (v)
+	  : "r" (0), "Ir" (CR_C), "Ir" (0x40)
+	  : "cc");
+}
+
+inline void cpu_leave_lowpower(void)
+{
+	unsigned int v;
+
+	asm volatile(
+	"mrc	p15, 0, %0, c1, c0, 0\n"
+	"	orr	%0, %0, %1\n"
+	"	mcr	p15, 0, %0, c1, c0, 0\n"
+	"	mrc	p15, 0, %0, c1, c0, 1\n"
+	"	orr	%0, %0, %2\n"
+	"	mcr	p15, 0, %0, c1, c0, 1\n"
+	  : "=&r" (v)
+	  : "Ir" (CR_C), "Ir" (0x40)
+	  : "cc");
+}
+
+void cpu_enter_lowpower(void)
+{
+	int id = 0;
+
+	/* check the cpuid */
+	asm("mrc p15, 0, %0, c0, c0, 0" : "=r"(id) : : "cc");
+
+	if ((id & 0xffffffff) == 0x411fc090)
+		ca9_enter_lowpower();
+	else
+		pr_warn(KERN_WARNING "Unknown CPU type\n");
+}
-- 
1.7.9.5

[RFC PATCH 2/6] ARM: imx: use the core cpu hotplug functions

[Sanjay Singh Rawat]

Generic arm cpu hotplug related functions are moved to core hotplug code,
remove the functions from the platform code.

Signed-off-by: Sanjay Singh Rawat <sanjay.rawat@linaro.org>
---
 arch/arm/mach-imx/hotplug.c |   22 +---------------------
 1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/arch/arm/mach-imx/hotplug.c b/arch/arm/mach-imx/hotplug.c
index 3daf1ed..280c6f3 100644
--- a/arch/arm/mach-imx/hotplug.c
+++ b/arch/arm/mach-imx/hotplug.c
@@ -14,30 +14,10 @@
 #include <linux/jiffies.h>
 #include <asm/cp15.h>
 #include <asm/proc-fns.h>
+#include <asm/hotplug.h>
 
 #include "common.h"
 
-static inline void cpu_enter_lowpower(void)
-{
-	unsigned int v;
-
-	asm volatile(
-		"mcr	p15, 0, %1, c7, c5, 0\n"
-	"	mcr	p15, 0, %1, c7, c10, 4\n"
-	/*
-	 * Turn off coherency
-	 */
-	"	mrc	p15, 0, %0, c1, c0, 1\n"
-	"	bic	%0, %0, %3\n"
-	"	mcr	p15, 0, %0, c1, c0, 1\n"
-	"	mrc	p15, 0, %0, c1, c0, 0\n"
-	"	bic	%0, %0, %2\n"
-	"	mcr	p15, 0, %0, c1, c0, 0\n"
-	  : "=&r" (v)
-	  : "r" (0), "Ir" (CR_C), "Ir" (0x40)
-	  : "cc");
-}
-
 /*
  * platform-specific code to shutdown a CPU
  *
-- 
1.7.9.5

[RFC PATCH 3/6] ARM: RealView: use the core cpu hotplug functions

[Sanjay Singh Rawat]

Generic arm cpu hotplug related functions are moved to core hotplug code,
remove the functions from the platform code.

Signed-off-by: Sanjay Singh Rawat <sanjay.rawat@linaro.org>
---
 arch/arm/mach-realview/hotplug.c |   37 +------------------------------------
 1 file changed, 1 insertion(+), 36 deletions(-)

diff --git a/arch/arm/mach-realview/hotplug.c b/arch/arm/mach-realview/hotplug.c
index ac22dd4..a48cc71 100644
--- a/arch/arm/mach-realview/hotplug.c
+++ b/arch/arm/mach-realview/hotplug.c
@@ -14,42 +14,7 @@
 
 #include <asm/cp15.h>
 #include <asm/smp_plat.h>
-
-static inline void cpu_enter_lowpower(void)
-{
-	unsigned int v;
-
-	asm volatile(
-	"	mcr	p15, 0, %1, c7, c5, 0\n"
-	"	mcr	p15, 0, %1, c7, c10, 4\n"
-	/*
-	 * Turn off coherency
-	 */
-	"	mrc	p15, 0, %0, c1, c0, 1\n"
-	"	bic	%0, %0, #0x20\n"
-	"	mcr	p15, 0, %0, c1, c0, 1\n"
-	"	mrc	p15, 0, %0, c1, c0, 0\n"
-	"	bic	%0, %0, %2\n"
-	"	mcr	p15, 0, %0, c1, c0, 0\n"
-	  : "=&r" (v)
-	  : "r" (0), "Ir" (CR_C)
-	  : "cc");
-}
-
-static inline void cpu_leave_lowpower(void)
-{
-	unsigned int v;
-
-	asm volatile(	"mrc	p15, 0, %0, c1, c0, 0\n"
-	"	orr	%0, %0, %1\n"
-	"	mcr	p15, 0, %0, c1, c0, 0\n"
-	"	mrc	p15, 0, %0, c1, c0, 1\n"
-	"	orr	%0, %0, #0x20\n"
-	"	mcr	p15, 0, %0, c1, c0, 1\n"
-	  : "=&r" (v)
-	  : "Ir" (CR_C)
-	  : "cc");
-}
+#include <asm/hotplug.h>
 
 static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
 {
-- 
1.7.9.5

[RFC PATCH 4/6] ARM: spear: use the core cpu hotplug functions

[Sanjay Singh Rawat]

Generic arm cpu hotplug related functions are moved to core hotplug code,
remove the functions from the platform code.

Signed-off-by: Sanjay Singh Rawat <sanjay.rawat@linaro.org>
---
 arch/arm/mach-spear/hotplug.c |   37 +------------------------------------
 1 file changed, 1 insertion(+), 36 deletions(-)

diff --git a/arch/arm/mach-spear/hotplug.c b/arch/arm/mach-spear/hotplug.c
index d97749c..988a9a6 100644
--- a/arch/arm/mach-spear/hotplug.c
+++ b/arch/arm/mach-spear/hotplug.c
@@ -15,42 +15,7 @@
 #include <linux/smp.h>
 #include <asm/cp15.h>
 #include <asm/smp_plat.h>
-
-static inline void cpu_enter_lowpower(void)
-{
-	unsigned int v;
-
-	asm volatile(
-	"	mcr	p15, 0, %1, c7, c5, 0\n"
-	"	dsb\n"
-	/*
-	 * Turn off coherency
-	 */
-	"	mrc	p15, 0, %0, c1, c0, 1\n"
-	"	bic	%0, %0, #0x20\n"
-	"	mcr	p15, 0, %0, c1, c0, 1\n"
-	"	mrc	p15, 0, %0, c1, c0, 0\n"
-	"	bic	%0, %0, %2\n"
-	"	mcr	p15, 0, %0, c1, c0, 0\n"
-	: "=&r" (v)
-	: "r" (0), "Ir" (CR_C)
-	: "cc", "memory");
-}
-
-static inline void cpu_leave_lowpower(void)
-{
-	unsigned int v;
-
-	asm volatile("mrc	p15, 0, %0, c1, c0, 0\n"
-	"	orr	%0, %0, %1\n"
-	"	mcr	p15, 0, %0, c1, c0, 0\n"
-	"	mrc	p15, 0, %0, c1, c0, 1\n"
-	"	orr	%0, %0, #0x20\n"
-	"	mcr	p15, 0, %0, c1, c0, 1\n"
-	: "=&r" (v)
-	: "Ir" (CR_C)
-	: "cc");
-}
+#include <asm/hotplug.h>
 
 static inline void spear13xx_do_lowpower(unsigned int cpu, int *spurious)
 {
-- 
1.7.9.5

[RFC PATCH 5/6] ARM: vexpress: use the core cpu hotplug functions

[Sanjay Singh Rawat]

Generic arm cpu hotplug related functions are moved to core hotplug code,
remove the functions from the platform code.

Signed-off-by: Sanjay Singh Rawat <sanjay.rawat@linaro.org>
---
 arch/arm/mach-vexpress/hotplug.c |   38 +-------------------------------------
 1 file changed, 1 insertion(+), 37 deletions(-)

diff --git a/arch/arm/mach-vexpress/hotplug.c b/arch/arm/mach-vexpress/hotplug.c
index f0ce6b8..cca1361 100644
--- a/arch/arm/mach-vexpress/hotplug.c
+++ b/arch/arm/mach-vexpress/hotplug.c
@@ -14,43 +14,7 @@
 
 #include <asm/smp_plat.h>
 #include <asm/cp15.h>
-
-static inline void cpu_enter_lowpower(void)
-{
-	unsigned int v;
-
-	asm volatile(
-		"mcr	p15, 0, %1, c7, c5, 0\n"
-	"	mcr	p15, 0, %1, c7, c10, 4\n"
-	/*
-	 * Turn off coherency
-	 */
-	"	mrc	p15, 0, %0, c1, c0, 1\n"
-	"	bic	%0, %0, %3\n"
-	"	mcr	p15, 0, %0, c1, c0, 1\n"
-	"	mrc	p15, 0, %0, c1, c0, 0\n"
-	"	bic	%0, %0, %2\n"
-	"	mcr	p15, 0, %0, c1, c0, 0\n"
-	  : "=&r" (v)
-	  : "r" (0), "Ir" (CR_C), "Ir" (0x40)
-	  : "cc");
-}
-
-static inline void cpu_leave_lowpower(void)
-{
-	unsigned int v;
-
-	asm volatile(
-		"mrc	p15, 0, %0, c1, c0, 0\n"
-	"	orr	%0, %0, %1\n"
-	"	mcr	p15, 0, %0, c1, c0, 0\n"
-	"	mrc	p15, 0, %0, c1, c0, 1\n"
-	"	orr	%0, %0, %2\n"
-	"	mcr	p15, 0, %0, c1, c0, 1\n"
-	  : "=&r" (v)
-	  : "Ir" (CR_C), "Ir" (0x40)
-	  : "cc");
-}
+#include <asm/hotplug.h>
 
 static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
 {
-- 
1.7.9.5

[RFC PATCH 6/6] ARM: EXYNOS: use the core cpu hotplug functions

[Sanjay Singh Rawat]

Generic arm cpu hotplug related functions are moved to core hotplug code,
Exynos-4 is having Cortex-A9, remove the functions from the platform code.

Signed-off-by: Sanjay Singh Rawat <sanjay.rawat@linaro.org>
---
 arch/arm/mach-exynos/hotplug.c |   40 ++--------------------------------------
 1 file changed, 2 insertions(+), 38 deletions(-)

diff --git a/arch/arm/mach-exynos/hotplug.c b/arch/arm/mach-exynos/hotplug.c
index af90cfa..3489760 100644
--- a/arch/arm/mach-exynos/hotplug.c
+++ b/arch/arm/mach-exynos/hotplug.c
@@ -21,30 +21,10 @@
 
 #include <mach/regs-pmu.h>
 #include <plat/cpu.h>
+#include <asm/hotplug.h>
 
 #include "common.h"
 
-static inline void cpu_enter_lowpower_a9(void)
-{
-	unsigned int v;
-
-	asm volatile(
-	"	mcr	p15, 0, %1, c7, c5, 0\n"
-	"	mcr	p15, 0, %1, c7, c10, 4\n"
-	/*
-	 * Turn off coherency
-	 */
-	"	mrc	p15, 0, %0, c1, c0, 1\n"
-	"	bic	%0, %0, %3\n"
-	"	mcr	p15, 0, %0, c1, c0, 1\n"
-	"	mrc	p15, 0, %0, c1, c0, 0\n"
-	"	bic	%0, %0, %2\n"
-	"	mcr	p15, 0, %0, c1, c0, 0\n"
-	  : "=&r" (v)
-	  : "r" (0), "Ir" (CR_C), "Ir" (0x40)
-	  : "cc");
-}
-
 static inline void cpu_enter_lowpower_a15(void)
 {
 	unsigned int v;
@@ -74,22 +54,6 @@ static inline void cpu_enter_lowpower_a15(void)
 	dsb();
 }
 
-static inline void cpu_leave_lowpower(void)
-{
-	unsigned int v;
-
-	asm volatile(
-	"mrc	p15, 0, %0, c1, c0, 0\n"
-	"	orr	%0, %0, %1\n"
-	"	mcr	p15, 0, %0, c1, c0, 0\n"
-	"	mrc	p15, 0, %0, c1, c0, 1\n"
-	"	orr	%0, %0, %2\n"
-	"	mcr	p15, 0, %0, c1, c0, 1\n"
-	  : "=&r" (v)
-	  : "Ir" (CR_C), "Ir" (0x40)
-	  : "cc");
-}
-
 static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
 {
 	for (;;) {
@@ -144,7 +108,7 @@ void __ref exynos_cpu_die(unsigned int cpu)
 	if ((primary_part & 0xfff0) == 0xc0f0)
 		cpu_enter_lowpower_a15();
 	else
-		cpu_enter_lowpower_a9();
+		cpu_enter_lowpower();
 
 	platform_do_lowpower(cpu, &spurious);
 
-- 
1.7.9.5

[RFC PATCH 4/6] ARM: spear: use the core cpu hotplug functions

[Viresh Kumar]

Please write spear as SPEAr.

On 20 May 2013 12:03, Sanjay Singh Rawat <sanjay.rawat@linaro.org> wrote:
> Generic arm cpu hotplug related functions are moved to core hotplug code,
> remove the functions from the platform code.
>
> Signed-off-by: Sanjay Singh Rawat <sanjay.rawat@linaro.org>
> ---
>  arch/arm/mach-spear/hotplug.c |   37 +------------------------------------
>  1 file changed, 1 insertion(+), 36 deletions(-)
>
> diff --git a/arch/arm/mach-spear/hotplug.c b/arch/arm/mach-spear/hotplug.c
> index d97749c..988a9a6 100644
> --- a/arch/arm/mach-spear/hotplug.c
> +++ b/arch/arm/mach-spear/hotplug.c
> @@ -15,42 +15,7 @@
>  #include <linux/smp.h>
>  #include <asm/cp15.h>
>  #include <asm/smp_plat.h>
> -
> -static inline void cpu_enter_lowpower(void)
> -{
> -       unsigned int v;
> -
> -       asm volatile(
> -       "       mcr     p15, 0, %1, c7, c5, 0\n"
> -       "       dsb\n"
> -       /*
> -        * Turn off coherency
> -        */
> -       "       mrc     p15, 0, %0, c1, c0, 1\n"
> -       "       bic     %0, %0, #0x20\n"
> -       "       mcr     p15, 0, %0, c1, c0, 1\n"
> -       "       mrc     p15, 0, %0, c1, c0, 0\n"
> -       "       bic     %0, %0, %2\n"
> -       "       mcr     p15, 0, %0, c1, c0, 0\n"
> -       : "=&r" (v)
> -       : "r" (0), "Ir" (CR_C)
> -       : "cc", "memory");
> -}
> -
> -static inline void cpu_leave_lowpower(void)
> -{
> -       unsigned int v;
> -
> -       asm volatile("mrc       p15, 0, %0, c1, c0, 0\n"
> -       "       orr     %0, %0, %1\n"
> -       "       mcr     p15, 0, %0, c1, c0, 0\n"
> -       "       mrc     p15, 0, %0, c1, c0, 1\n"
> -       "       orr     %0, %0, #0x20\n"
> -       "       mcr     p15, 0, %0, c1, c0, 1\n"
> -       : "=&r" (v)
> -       : "Ir" (CR_C)
> -       : "cc");
> -}

I am not the best at assembly code but I can see that the
two codes (here and hotplug.c) are slightly different.

How can we ensure if this patch is okay?

[RFC PATCH 2/6] ARM: imx: use the core cpu hotplug functions

[Russell King - ARM Linux]

Please read back on this list for my comments about such moves of this
very code.  You're not the first.

On Mon, May 20, 2013 at 12:03:24PM +0530, Sanjay Singh Rawat wrote:
> Generic arm cpu hotplug related functions are moved to core hotplug code,
> remove the functions from the platform code.
> 
> Signed-off-by: Sanjay Singh Rawat <sanjay.rawat@linaro.org>
> ---
>  arch/arm/mach-imx/hotplug.c |   22 +---------------------
>  1 file changed, 1 insertion(+), 21 deletions(-)
> 
> diff --git a/arch/arm/mach-imx/hotplug.c b/arch/arm/mach-imx/hotplug.c
> index 3daf1ed..280c6f3 100644
> --- a/arch/arm/mach-imx/hotplug.c
> +++ b/arch/arm/mach-imx/hotplug.c
> @@ -14,30 +14,10 @@
>  #include <linux/jiffies.h>
>  #include <asm/cp15.h>
>  #include <asm/proc-fns.h>
> +#include <asm/hotplug.h>
>  
>  #include "common.h"
>  
> -static inline void cpu_enter_lowpower(void)
> -{
> -	unsigned int v;
> -
> -	asm volatile(
> -		"mcr	p15, 0, %1, c7, c5, 0\n"
> -	"	mcr	p15, 0, %1, c7, c10, 4\n"
> -	/*
> -	 * Turn off coherency
> -	 */
> -	"	mrc	p15, 0, %0, c1, c0, 1\n"
> -	"	bic	%0, %0, %3\n"
> -	"	mcr	p15, 0, %0, c1, c0, 1\n"
> -	"	mrc	p15, 0, %0, c1, c0, 0\n"
> -	"	bic	%0, %0, %2\n"
> -	"	mcr	p15, 0, %0, c1, c0, 0\n"
> -	  : "=&r" (v)
> -	  : "r" (0), "Ir" (CR_C), "Ir" (0x40)
> -	  : "cc");
> -}
> -
>  /*
>   * platform-specific code to shutdown a CPU
>   *
> -- 
> 1.7.9.5
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel