[PATCH v5 3/6] ARM: smp_scu: allow the platform code to read the SCU CPU status
Martin Blumenstingl
martin.blumenstingl at googlemail.com
Fri Jul 28 14:21:35 PDT 2017
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 at 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 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
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