[PATCH] arm64: psci: Support generic pm suspend withtout CPUIDLE subsystem's help.

[PATCH] arm64: psci: Support generic pm suspend withtout CPUIDLE subsystem's help.

[Jonghwa Lee]

Current psci's cpu_suspend callback can be used only when common cpu idle
configuration is enabled. However, it's also needed for system which only
uses generic pm suspend not cpu idle. This patch modifies psci driver to
support both of cases.

Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com>
---
 arch/arm64/kernel/psci.c |   41 +++++++++++++++++++++++++++++------------
 1 file changed, 29 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
index f1dbca7..06d5527 100644
--- a/arch/arm64/kernel/psci.c
+++ b/arch/arm64/kernel/psci.c
@@ -35,6 +35,13 @@
 #define PSCI_POWER_STATE_TYPE_STANDBY		0
 #define PSCI_POWER_STATE_TYPE_POWER_DOWN	1
 
+enum psci_affinity_level {
+	PSCI_AFFINITY_LEVEL_0,
+	PSCI_AFFINITY_LEVEL_1,
+	PSCI_AFFINITY_LEVEL_2,
+	PSCI_AFFINITY_LEVEL_3,
+};
+
 struct psci_power_state {
 	u16	id;
 	u8	type;
@@ -513,27 +520,37 @@ static int psci_suspend_finisher(unsigned long index)
 {
 	struct psci_power_state *state = __this_cpu_read(psci_power_state);
 
+	/* Generic PM suspend without CPUIDLE functionality */
+	if (!state) {
+		struct psci_power_state s = {
+			.affinity_level = PSCI_AFFINITY_LEVEL_3,
+			.type = PSCI_POWER_STATE_TYPE_POWER_DOWN,
+		};
+		return psci_ops.cpu_suspend(s, virt_to_phys(cpu_resume));
+	}
+
 	return psci_ops.cpu_suspend(state[index - 1],
 				    virt_to_phys(cpu_resume));
 }
 
 static int __maybe_unused cpu_psci_cpu_suspend(unsigned long index)
 {
-	int ret;
 	struct psci_power_state *state = __this_cpu_read(psci_power_state);
-	/*
-	 * idle state index 0 corresponds to wfi, should never be called
-	 * from the cpu_suspend operations
-	 */
-	if (WARN_ON_ONCE(!index))
-		return -EINVAL;
 
-	if (state[index - 1].type == PSCI_POWER_STATE_TYPE_STANDBY)
-		ret = psci_ops.cpu_suspend(state[index - 1], 0);
-	else
-		ret = __cpu_suspend(index, psci_suspend_finisher);
+	if (state) {
+		if (WARN_ON_ONCE(!index))
+			return -EINVAL;
+
+		/*
+		 * If idle state initialization is successfully done,
+		 * idle state index 0 corresponds to wfi, should never be
+		 * called from the cpu_suspend operations
+		 */
+		if (state[index - 1].type == PSCI_POWER_STATE_TYPE_STANDBY)
+			return psci_ops.cpu_suspend(state[index - 1], 0);
+	}
 
-	return ret;
+	return __cpu_suspend(index, psci_suspend_finisher);
 }
 
 const struct cpu_operations cpu_psci_ops = {
-- 
1.7.9.5

[PATCH] arm64: psci: Support generic pm suspend withtout CPUIDLE subsystem's help.

[Lorenzo Pieralisi]

On Fri, Dec 19, 2014 at 05:32:54AM +0000, Jonghwa Lee wrote:
> Current psci's cpu_suspend callback can be used only when common cpu idle
> configuration is enabled. However, it's also needed for system which only
> uses generic pm suspend not cpu idle. This patch modifies psci driver to
> support both of cases.
> 
> Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com>

NAK. Apart from:

1) being buggy (how can you use your code when both SUSPEND and CPUidle
   are on)
2) not providing a patch to show how you use the API

that's not how I planned to implement system suspend, bear with me for
a couple of days and I will post an RFC publicly beginning of January.

Amit already posted a different solution and I've already replied to him:
http://www.spinics.net/lists/arm-kernel/msg373447.html

Lorenzo

> ---
>  arch/arm64/kernel/psci.c |   41 +++++++++++++++++++++++++++++------------
>  1 file changed, 29 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
> index f1dbca7..06d5527 100644
> --- a/arch/arm64/kernel/psci.c
> +++ b/arch/arm64/kernel/psci.c
> @@ -35,6 +35,13 @@
>  #define PSCI_POWER_STATE_TYPE_STANDBY		0
>  #define PSCI_POWER_STATE_TYPE_POWER_DOWN	1
>  
> +enum psci_affinity_level {
> +	PSCI_AFFINITY_LEVEL_0,
> +	PSCI_AFFINITY_LEVEL_1,
> +	PSCI_AFFINITY_LEVEL_2,
> +	PSCI_AFFINITY_LEVEL_3,
> +};
> +
>  struct psci_power_state {
>  	u16	id;
>  	u8	type;
> @@ -513,27 +520,37 @@ static int psci_suspend_finisher(unsigned long index)
>  {
>  	struct psci_power_state *state = __this_cpu_read(psci_power_state);
>  
> +	/* Generic PM suspend without CPUIDLE functionality */
> +	if (!state) {
> +		struct psci_power_state s = {
> +			.affinity_level = PSCI_AFFINITY_LEVEL_3,
> +			.type = PSCI_POWER_STATE_TYPE_POWER_DOWN,
> +		};
> +		return psci_ops.cpu_suspend(s, virt_to_phys(cpu_resume));
> +	}
> +
>  	return psci_ops.cpu_suspend(state[index - 1],
>  				    virt_to_phys(cpu_resume));
>  }
>  
>  static int __maybe_unused cpu_psci_cpu_suspend(unsigned long index)
>  {
> -	int ret;
>  	struct psci_power_state *state = __this_cpu_read(psci_power_state);
> -	/*
> -	 * idle state index 0 corresponds to wfi, should never be called
> -	 * from the cpu_suspend operations
> -	 */
> -	if (WARN_ON_ONCE(!index))
> -		return -EINVAL;
>  
> -	if (state[index - 1].type == PSCI_POWER_STATE_TYPE_STANDBY)
> -		ret = psci_ops.cpu_suspend(state[index - 1], 0);
> -	else
> -		ret = __cpu_suspend(index, psci_suspend_finisher);
> +	if (state) {
> +		if (WARN_ON_ONCE(!index))
> +			return -EINVAL;
> +
> +		/*
> +		 * If idle state initialization is successfully done,
> +		 * idle state index 0 corresponds to wfi, should never be
> +		 * called from the cpu_suspend operations
> +		 */
> +		if (state[index - 1].type == PSCI_POWER_STATE_TYPE_STANDBY)
> +			return psci_ops.cpu_suspend(state[index - 1], 0);
> +	}
>  
> -	return ret;
> +	return __cpu_suspend(index, psci_suspend_finisher);
>  }
>  
>  const struct cpu_operations cpu_psci_ops = {
> -- 
> 1.7.9.5
> 
>