[PATCH v6 2/6] ARM: smp_scu: add a helper for powering on a specific CPU
From: Martin Blumenstingl <hidden>
Date: 2017-08-14 21:58:56
Also in:
linux-amlogic, linux-arm-kernel
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
To boot the secondary CPUs on the Amlogic Meson8/Meson8m2 (Cortex-A9) and Meson8b (Cortex-A5) SoCs we have to enable SCU mode SCU_PM_NORMAL, otherwise the secondary cores will not start. This patch adds a scu_cpu_power_enable() function which can be used to enable SCU_PM_NORMAL for a specific (logical) CPU. An internal helper function is also created, to avoid code duplication with scu_power_mode(). Signed-off-by: Martin Blumenstingl <martin.blumenstingl-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org> --- arch/arm/include/asm/smp_scu.h | 6 ++++++ arch/arm/kernel/smp_scu.c | 35 +++++++++++++++++++++++++---------- 2 files changed, 31 insertions(+), 10 deletions(-)
diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h
index bfe163c40024..11e636f33ed9 100644
--- a/arch/arm/include/asm/smp_scu.h
+++ b/arch/arm/include/asm/smp_scu.h@@ -26,6 +26,7 @@ static inline unsigned long scu_a9_get_base(void) #ifdef CONFIG_HAVE_ARM_SCU unsigned int scu_get_core_count(void __iomem *); int scu_power_mode(void __iomem *, unsigned int); +int scu_cpu_power_enable(void __iomem *, unsigned int); #else static inline unsigned int scu_get_core_count(void __iomem *scu_base) {
@@ -35,6 +36,11 @@ static inline int scu_power_mode(void __iomem *scu_base, unsigned int mode) { return -EINVAL; } +static inline int scu_cpu_power_enable(void __iomem *scu_base, + unsigned int mode) +{ + return -EINVAL; +} #endif #if defined(CONFIG_SMP) && defined(CONFIG_HAVE_ARM_SCU)
diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c
index 72f9241ad5db..1d549c16b5fc 100644
--- a/arch/arm/kernel/smp_scu.c
+++ b/arch/arm/kernel/smp_scu.c@@ -72,18 +72,12 @@ void scu_enable(void __iomem *scu_base) } #endif -/* - * Set the executing CPUs power mode as defined. This will be in - * preparation for it executing a WFI instruction. - * - * This function must be called with preemption disabled, and as it - * has the side effect of disabling coherency, caches must have been - * flushed. Interrupts must also have been disabled. - */ -int scu_power_mode(void __iomem *scu_base, unsigned int mode) +static int scu_set_power_mode_internal(void __iomem *scu_base, + unsigned int logical_cpu, + unsigned int mode) { unsigned int val; - int cpu = MPIDR_AFFINITY_LEVEL(cpu_logical_map(smp_processor_id()), 0); + int cpu = MPIDR_AFFINITY_LEVEL(cpu_logical_map(logical_cpu), 0); if (mode > 3 || mode == 1 || cpu > 3) return -EINVAL;
@@ -94,3 +88,24 @@ int scu_power_mode(void __iomem *scu_base, unsigned int mode) return 0; } + +/* + * Set the executing CPUs power mode as defined. This will be in + * preparation for it executing a WFI instruction. + * + * This function must be called with preemption disabled, and as it + * has the side effect of disabling coherency, caches must have been + * flushed. Interrupts must also have been disabled. + */ +int scu_power_mode(void __iomem *scu_base, unsigned int mode) +{ + return scu_set_power_mode_internal(scu_base, smp_processor_id(), mode); +} + +/* + * Set the given (logical) CPU's power mode to SCU_PM_NORMAL. + */ +int scu_cpu_power_enable(void __iomem *scu_base, unsigned int cpu) +{ + return scu_set_power_mode_internal(scu_base, cpu, SCU_PM_NORMAL); +}
--
2.14.1
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