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Commit 712eddf7 authored by Bartlomiej Zolnierkiewicz's avatar Bartlomiej Zolnierkiewicz Committed by Kukjin Kim
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cpuidle: exynos: add coupled cpuidle support for exynos4210 

The following patch adds coupled cpuidle support for Exynos4210 to
an existing cpuidle-exynos driver.  As a result it enables AFTR mode
to be used by default on Exynos4210 without the need to hot unplug
CPU1 first.

The patch is heavily based on earlier cpuidle-exynos4210 driver from
Daniel Lezcano:

http://www.spinics.net/lists/linux-samsung-soc/msg28134.html



Changes from Daniel's code include:
- porting code to current kernels
- fixing it to work on my setup (by using S5P_INFORM register
  instead of S5P_VA_SYSRAM one on Revison 1.1 and retrying poking
  CPU1 out of the BOOT ROM if necessary)
- fixing rare lockup caused by waiting for CPU1 to get stuck in
  the BOOT ROM (CPU hotplug code in arch/arm/mach-exynos/platsmp.c
  doesn't require this and works fine)
- moving Exynos specific code to arch/arm/mach-exynos/pm.c
- using cpu_boot_reg_base() helper instead of BOOT_VECTOR macro
- using exynos_cpu_*() helpers instead of accessing registers
  directly
- using arch_send_wakeup_ipi_mask() instead of dsb_sev()
  (this matches CPU hotplug code in arch/arm/mach-exynos/platsmp.c)
- integrating separate exynos4210-cpuidle driver into existing
  exynos-cpuidle one

Cc: Colin Cross <ccross@google.com>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: default avatarBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: default avatarKukjin Kim <kgene@kernel.org>
parent 865e8b76

arch/arm/mach-exynos/common.h

+4 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#define __ARCH_ARM_MACH_EXYNOS_COMMON_H



#include <linux/of.h>

#include <linux/platform_data/cpuidle-exynos.h>



#define EXYNOS3250_SOC_ID	0xE3472000

#define EXYNOS3_SOC_MASK	0xFFFFF000
@@ -150,8 +151,11 @@ extern void exynos_pm_central_suspend(void); 
extern int exynos_pm_central_resume(void);

extern void exynos_enter_aftr(void);



extern struct cpuidle_exynos_data cpuidle_coupled_exynos_data;



extern void s5p_init_cpu(void __iomem *cpuid_addr);

extern unsigned int samsung_rev(void);

extern void __iomem *cpu_boot_reg_base(void);



static inline void pmu_raw_writel(u32 val, u32 offset)

{

arch/arm/mach-exynos/exynos.c

+4 −0
Original line number Diff line number Diff line
@@ -246,6 +246,10 @@ static void __init exynos_dt_machine_init(void) 
	if (!IS_ENABLED(CONFIG_SMP))

		exynos_sysram_init();



#ifdef CONFIG_ARM_EXYNOS_CPUIDLE

	if (of_machine_is_compatible("samsung,exynos4210"))

		exynos_cpuidle.dev.platform_data = &cpuidle_coupled_exynos_data;

#endif

	if (of_machine_is_compatible("samsung,exynos4210") ||

	    of_machine_is_compatible("samsung,exynos4212") ||

	    (of_machine_is_compatible("samsung,exynos4412") &&

arch/arm/mach-exynos/platsmp.c

+1 −1
Original line number Diff line number Diff line
@@ -194,7 +194,7 @@ int exynos_cluster_power_state(int cluster) 
		S5P_CORE_LOCAL_PWR_EN);

}



static inline void __iomem *cpu_boot_reg_base(void)

void __iomem *cpu_boot_reg_base(void)

{

	if (soc_is_exynos4210() && samsung_rev() == EXYNOS4210_REV_1_1)

		return pmu_base_addr + S5P_INFORM5;

arch/arm/mach-exynos/pm.c

+122 −0
Original line number Diff line number Diff line
@@ -179,3 +179,125 @@ void exynos_enter_aftr(void) 


	cpu_pm_exit();

}



static atomic_t cpu1_wakeup = ATOMIC_INIT(0);



static int exynos_cpu0_enter_aftr(void)

{

	int ret = -1;



	/*

	 * If the other cpu is powered on, we have to power it off, because

	 * the AFTR state won't work otherwise

	 */

	if (cpu_online(1)) {

		/*

		 * We reach a sync point with the coupled idle state, we know

		 * the other cpu will power down itself or will abort the

		 * sequence, let's wait for one of these to happen

		 */

		while (exynos_cpu_power_state(1)) {

			/*

			 * The other cpu may skip idle and boot back

			 * up again

			 */

			if (atomic_read(&cpu1_wakeup))

				goto abort;



			/*

			 * The other cpu may bounce through idle and

			 * boot back up again, getting stuck in the

			 * boot rom code

			 */

			if (__raw_readl(cpu_boot_reg_base()) == 0)

				goto abort;



			cpu_relax();

		}

	}



	exynos_enter_aftr();

	ret = 0;



abort:

	if (cpu_online(1)) {

		/*

		 * Set the boot vector to something non-zero

		 */

		__raw_writel(virt_to_phys(exynos_cpu_resume),

			     cpu_boot_reg_base());

		dsb();



		/*

		 * Turn on cpu1 and wait for it to be on

		 */

		exynos_cpu_power_up(1);

		while (exynos_cpu_power_state(1) != S5P_CORE_LOCAL_PWR_EN)

			cpu_relax();



		while (!atomic_read(&cpu1_wakeup)) {

			/*

			 * Poke cpu1 out of the boot rom

			 */

			__raw_writel(virt_to_phys(exynos_cpu_resume),

				     cpu_boot_reg_base());



			arch_send_wakeup_ipi_mask(cpumask_of(1));

		}

	}



	return ret;

}



static int exynos_wfi_finisher(unsigned long flags)

{

	cpu_do_idle();



	return -1;

}



static int exynos_cpu1_powerdown(void)

{

	int ret = -1;



	/*

	 * Idle sequence for cpu1

	 */

	if (cpu_pm_enter())

		goto cpu1_aborted;



	/*

	 * Turn off cpu 1

	 */

	exynos_cpu_power_down(1);



	ret = cpu_suspend(0, exynos_wfi_finisher);



	cpu_pm_exit();



cpu1_aborted:

	dsb();

	/*

	 * Notify cpu 0 that cpu 1 is awake

	 */

	atomic_set(&cpu1_wakeup, 1);



	return ret;

}



static void exynos_pre_enter_aftr(void)

{

	__raw_writel(virt_to_phys(exynos_cpu_resume), cpu_boot_reg_base());

}



static void exynos_post_enter_aftr(void)

{

	atomic_set(&cpu1_wakeup, 0);

}



struct cpuidle_exynos_data cpuidle_coupled_exynos_data = {

	.cpu0_enter_aftr		= exynos_cpu0_enter_aftr,

	.cpu1_powerdown		= exynos_cpu1_powerdown,

	.pre_enter_aftr		= exynos_pre_enter_aftr,

	.post_enter_aftr		= exynos_post_enter_aftr,

};

drivers/cpuidle/Kconfig.arm

+1 −0
Original line number Diff line number Diff line
@@ -55,6 +55,7 @@ config ARM_AT91_CPUIDLE 
config ARM_EXYNOS_CPUIDLE

	bool "Cpu Idle Driver for the Exynos processors"

	depends on ARCH_EXYNOS

	select ARCH_NEEDS_CPU_IDLE_COUPLED if SMP

	help

	  Select this to enable cpuidle for Exynos processors