On Mon, Dec 01, 2014 at 08:08:55AM +0000, amit daniel kachhap wrote:

On Thu, Oct 30, 2014 at 4:16 PM, Lorenzo Pieralisi
[off-list ref] wrote:

quoted

On Thu, Oct 30, 2014 at 03:55:38AM +0000, Amit Daniel Kachhap wrote:

quoted

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.

Hi Lorenzo,

Any update on this API for system sleep.

Hi Amit,

Sorry for the delay in replying, I am working on it at the moment, we will
post the API in the coming weeks.

Thank you,
Lorenzo

Regards,
Amit

quoted

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

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

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