[PATCH 3/3] arm64: psci: Add support to call cpu_suspend with deepest C state.
From: Lorenzo Pieralisi <hidden>
Date: 2014-10-30 10:46:30
Also in:
linux-pm
On Thu, Oct 30, 2014 at 03:55:38AM +0000, Amit Daniel Kachhap wrote:
This feature will be useful for system suspend/resume which may intend to invoke cpu_suspend with deepest possible C state level.
We are working on defining system states in the PSCI specification, but it is not set in stone yet (Cc'ed Charles). I guess you are posting this code because you have already an implementation that supports system suspend/resume, so I am taking an immediate action to come up with an API suitable for that asap. On a side note I do not necessarily like this magic idle index logic, I prefer adding an API for that, that translates the call into whatever is required by the back-end (ie PSCI) implementation. Thanks, Lorenzo
quoted hunk ↗ jump to hunk
Signed-off-by: Amit Daniel Kachhap <redacted> --- arch/arm64/include/asm/psci.h | 2 ++ arch/arm64/kernel/psci.c | 8 ++++++++ 2 files changed, 10 insertions(+)diff --git a/arch/arm64/include/asm/psci.h b/arch/arm64/include/asm/psci.h index e5312ea..487e52b 100644 --- a/arch/arm64/include/asm/psci.h +++ b/arch/arm64/include/asm/psci.h@@ -14,6 +14,8 @@ #ifndef __ASM_PSCI_H #define __ASM_PSCI_H +#define CPU_PSCI_IDLE_INDEX_MAX 0xff + int psci_init(void); #endif /* __ASM_PSCI_H */diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c index 4ebc146..a761513 100644 --- a/arch/arm64/kernel/psci.c +++ b/arch/arm64/kernel/psci.c@@ -70,6 +70,7 @@ enum psci_function { static DEFINE_PER_CPU_READ_MOSTLY(struct psci_power_state *, psci_power_state); static u32 psci_function_id[PSCI_FN_MAX]; +static u32 cpu_psci_idle_state_count; static int psci_to_linux_errno(int errno) {@@ -239,6 +240,8 @@ static int __maybe_unused cpu_psci_cpu_init_idle(struct device_node *cpu_node, if (!count) return -ENODEV; + cpu_psci_idle_state_count = count; + psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL); if (!psci_states) return -ENOMEM;@@ -521,6 +524,11 @@ static int __maybe_unused cpu_psci_cpu_suspend(unsigned long index) { int ret; struct psci_power_state *state = __get_cpu_var(psci_power_state); + + /* Check and select the deepest idle state */ + if (index == CPU_PSCI_IDLE_INDEX_MAX) + index = cpu_psci_idle_state_count; + /* * idle state index 0 corresponds to wfi, should never be called * from the cpu_suspend operations.-- 1.9.1