[PATCH v6 3/6] ARM: smp_scu: allow the platform code to read the SCU CPU status
From: martin.blumenstingl@googlemail.com (Martin Blumenstingl)
Date: 2017-08-14 21:58:57
Also in:
linux-amlogic, linux-devicetree
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
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. While here, replace the magic number 0x3 with a preprocessor macro (SCU_CPU_STATUS_MASK) so we don't have to duplicate this magic number in the new function. Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> --- 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 1d549c16b5fc..c6b33074c393 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);
@@ -109,3 +111,17 @@ 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; +}
--
2.14.1