On Amlogic Meson8 / Meson8m2 (both Cortex-A9) and Meson8b (Cortex-A5) the CPU hotplug code needs to wait until the SCU status of the CPU that is being taken offline is SCU_PM_POWEROFF. Provide a utility function (which can be invoked for example from .cpu_kill()) which allows reading the SCU status of a CPU. Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx> --- arch/arm/include/asm/smp_scu.h | 6 ++++++ arch/arm/kernel/smp_scu.c | 18 +++++++++++++++++- 2 files changed, 23 insertions(+), 1 deletion(-) diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h index 11e636f33ed9..992b34c4267f 100644 --- a/arch/arm/include/asm/smp_scu.h +++ b/arch/arm/include/asm/smp_scu.h @@ -27,6 +27,7 @@ static inline unsigned long scu_a9_get_base(void) 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); +int scu_get_cpu_power_mode(void __iomem *scu_base, unsigned int logical_cpu); #else static inline unsigned int scu_get_core_count(void __iomem *scu_base) { @@ -41,6 +42,11 @@ static inline int scu_cpu_power_enable(void __iomem *scu_base, { return -EINVAL; } +static inline int scu_get_cpu_power_mode(void __iomem *scu_base, + unsigned int logical_cpu) +{ + 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 ef09121b18eb..942f8acb82c1 100644 --- a/arch/arm/kernel/smp_scu.c +++ b/arch/arm/kernel/smp_scu.c @@ -21,6 +21,7 @@ #define SCU_STANDBY_ENABLE (1 << 5) #define SCU_CONFIG 0x04 #define SCU_CPU_STATUS 0x08 +#define SCU_CPU_STATUS_MASK GENMASK(1, 0) #define SCU_INVALIDATE 0x0c #define SCU_FPGA_REVISION 0x10 @@ -82,7 +83,8 @@ static int scu_set_power_mode_internal(void __iomem *scu_base, if (mode > 3 || mode == 1 || cpu > 3) return -EINVAL; - val = readb_relaxed(scu_base + SCU_CPU_STATUS + cpu) & ~0x03; + val = readb_relaxed(scu_base + SCU_CPU_STATUS + cpu); + val &= ~SCU_CPU_STATUS_MASK; val |= mode; writeb_relaxed(val, scu_base + SCU_CPU_STATUS + cpu); @@ -113,3 +115,17 @@ int scu_cpu_power_enable(void __iomem *scu_base, unsigned int cpu) { return scu_set_power_mode_internal(scu_base, cpu, SCU_PM_NORMAL); } + +int scu_get_cpu_power_mode(void __iomem *scu_base, unsigned int logical_cpu) +{ + unsigned int val; + int cpu = MPIDR_AFFINITY_LEVEL(cpu_logical_map(logical_cpu), 0); + + if (cpu > 3) + return -EINVAL; + + val = readb_relaxed(scu_base + SCU_CPU_STATUS + cpu); + val &= SCU_CPU_STATUS_MASK; + + return val; +} -- 2.13.3 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html