PSCI v1.0 augmented the power_state parameter format specification
(extended stateid) and introduced a way to probe it through the
PSCI_FEATURES interface.
This patch implements code that detects the power_state format at
run-time through the PSCI_FEATURES interface, so that the power_state
argument can be properly detected and validated in the kernel according
to the information provided through firmware.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieral...@arm.com>
Cc: Mark Rutland <mark.rutl...@arm.com>
---
drivers/firmware/psci.c | 34 ++++++++++++++++++++++++++++++++--
include/uapi/linux/psci.h | 12 ++++++++++++
2 files changed, 44 insertions(+), 2 deletions(-)
diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index 2330099..4063784 100644
--- a/drivers/firmware/psci.c
+++ b/drivers/firmware/psci.c
@@ -74,14 +74,34 @@ static u32 psci_function_id[PSCI_FN_MAX];
PSCI_0_2_POWER_STATE_TYPE_MASK | \
PSCI_0_2_POWER_STATE_AFFL_MASK)
+#define PSCI_EXT_POWER_STATE_MASK \
+ (PSCI_EXT_POWER_STATE_ID_MASK | \
+ PSCI_EXT_POWER_STATE_TYPE_MASK)
+
+static u32 psci_cpu_suspend_feature;
+
+static inline bool psci_has_ext_power_state(void)
+{
+ return psci_cpu_suspend_feature &
+ PSCI_FEATURES_CPU_SUSPEND_PF_MASK;
+}
+
bool psci_power_state_loses_context(u32 state)
{
- return state & PSCI_0_2_POWER_STATE_TYPE_MASK;
+ const u32 mask = psci_has_ext_power_state() ?
+ PSCI_EXT_POWER_STATE_TYPE_MASK :
+ PSCI_0_2_POWER_STATE_TYPE_MASK;
+
+ return state & mask;
}
bool psci_power_state_is_valid(u32 state)
{
- return !(state & ~PSCI_0_2_POWER_STATE_MASK);
+ const u32 valid_mask = psci_has_ext_power_state() ?
+ PSCI_EXT_POWER_STATE_MASK :
+ PSCI_0_2_POWER_STATE_MASK;
+
+ return !(state & ~valid_mask);
}
static int psci_to_linux_errno(int errno)
@@ -202,6 +222,14 @@ static int __init psci_features(u32 psci_func_id)
psci_func_id, 0, 0);
}
+static void __init psci_init_cpu_suspend(void)
+{
+ int feature = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
+
+ if (feature != PSCI_RET_NOT_SUPPORTED)
+ psci_cpu_suspend_feature = feature;
+}
+
/*
* Detect the presence of a resident Trusted OS which may cause CPU_OFF to
* return DENIED (which would be fatal).
@@ -280,6 +308,8 @@ static int __init psci_probe(void)
psci_init_migrate();
+ psci_init_cpu_suspend();
+
return 0;
}
diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
index 187b828d..2598d7c 100644
--- a/include/uapi/linux/psci.h
+++ b/include/uapi/linux/psci.h
@@ -58,6 +58,13 @@
#define PSCI_0_2_POWER_STATE_AFFL_MASK \
(0x3 << PSCI_0_2_POWER_STATE_AFFL_SHIFT)
+/* PSCI extended power state encoding for CPU_SUSPEND function */
+#define PSCI_EXT_POWER_STATE_ID_MASK 0xfffffff
+#define PSCI_EXT_POWER_STATE_ID_SHIFT 0
+#define PSCI_EXT_POWER_STATE_TYPE_SHIFT 30
+#define PSCI_EXT_POWER_STATE_TYPE_MASK \
+ (0x1 << PSCI_EXT_POWER_STATE_TYPE_SHIFT)
+
/* PSCI v0.2 affinity level state returned by AFFINITY_INFO */
#define PSCI_0_2_AFFINITY_LEVEL_ON 0
#define PSCI_0_2_AFFINITY_LEVEL_OFF 1
@@ -78,6 +85,11 @@
#define PSCI_VERSION_MINOR(ver) \
((ver) & PSCI_VERSION_MINOR_MASK)
+/* PSCI features decoding (>=1.0) */
+#define PSCI_FEATURES_CPU_SUSPEND_PF_SHIFT 1
+#define PSCI_FEATURES_CPU_SUSPEND_PF_MASK \
+ (0x1 << PSCI_FEATURES_CPU_SUSPEND_PF_SHIFT)
+
/* PSCI return values (inclusive of all PSCI versions) */
#define PSCI_RET_SUCCESS 0
#define PSCI_RET_NOT_SUPPORTED -1
--
2.2.1
--
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