[RFC PATCH 0/3] arm: psci: implement cpuidle_ops

[RFC PATCH 0/3] arm: psci: implement cpuidle_ops

[Jisheng Zhang]

We'd like to use cpuidle-arm.c for both arm and arm64 with psci as backend.
For arm64, it works. But for arm, we miss cpuidle_ops, these patches try to
address this issue.

Has been tested on Marvell Berlin SoCs. These patches are rebased on the Mark
Rutland's latest psci unification work.

[PATCH 1/3] renames psci_smp.c to psci.c to prepare for the next two changes.
[PATCH 2/3] enables PSCI on UP systems so that some calls like cpu_suspend can
be made functional on UP too
[PATCH 3/3] add the cpuidle_ops for psci. Most code is stolen from arm64, which
introduce duplicated psci code, that's why it's marked as "RFC", I dunno where
to put cpu_psci_cpu_init_idle() related functions.

Comments are welcome!


Jisheng Zhang (3):
  arm: psci: rename psci_smp.c to psci.c
  arm: psci: enable PSCI on UP systems
  arm: psci: add cpuidle_ops support

 arch/arm/kernel/Makefile   |   5 +-
 arch/arm/kernel/psci.c     | 248 +++++++++++++++++++++++++++++++++++++++++++++
 arch/arm/kernel/psci_smp.c | 130 ------------------------
 3 files changed, 249 insertions(+), 134 deletions(-)
 create mode 100644 arch/arm/kernel/psci.c
 delete mode 100644 arch/arm/kernel/psci_smp.c

-- 
2.1.4

[RFC PATCH 1/3] arm: psci: rename psci_smp.c to psci.c

[Jisheng Zhang]

This will prepare for next commit to enable PSCI for UP systems so that
calls like cpu_suspend can be made functional on UP too.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
 arch/arm/kernel/Makefile   |   2 +-
 arch/arm/kernel/psci.c     | 130 +++++++++++++++++++++++++++++++++++++++++++++
 arch/arm/kernel/psci_smp.c | 130 ---------------------------------------------
 3 files changed, 131 insertions(+), 131 deletions(-)
 create mode 100644 arch/arm/kernel/psci.c
 delete mode 100644 arch/arm/kernel/psci_smp.c

diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 3b995f5..c57b2c0 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -90,7 +90,7 @@ obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 obj-$(CONFIG_ARM_VIRT_EXT)	+= hyp-stub.o
 ifeq ($(CONFIG_ARM_PSCI),y)
 obj-y				+= psci-call.o
-obj-$(CONFIG_SMP)		+= psci_smp.o
+obj-$(CONFIG_SMP)		+= psci.o
 endif
 
 extra-y := $(head-y) vmlinux.lds
diff --git a/arch/arm/kernel/psci.c b/arch/arm/kernel/psci.c
new file mode 100644
index 0000000..61c04b0
--- /dev/null
+++ b/arch/arm/kernel/psci.c
@@ -0,0 +1,130 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2012 ARM Limited
+ *
+ * Author: Will Deacon <will.deacon@arm.com>
+ */
+
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/of.h>
+#include <linux/delay.h>
+#include <linux/psci.h>
+
+#include <uapi/linux/psci.h>
+
+#include <asm/psci.h>
+#include <asm/smp_plat.h>
+
+/*
+ * psci_smp assumes that the following is true about PSCI:
+ *
+ * cpu_suspend   Suspend the execution on a CPU
+ * @state        we don't currently describe affinity levels, so just pass 0.
+ * @entry_point  the first instruction to be executed on return
+ * returns 0  success, < 0 on failure
+ *
+ * cpu_off       Power down a CPU
+ * @state        we don't currently describe affinity levels, so just pass 0.
+ * no return on successful call
+ *
+ * cpu_on        Power up a CPU
+ * @cpuid        cpuid of target CPU, as from MPIDR
+ * @entry_point  the first instruction to be executed on return
+ * returns 0  success, < 0 on failure
+ *
+ * migrate       Migrate the context to a different CPU
+ * @cpuid        cpuid of target CPU, as from MPIDR
+ * returns 0  success, < 0 on failure
+ *
+ */
+
+extern void secondary_startup(void);
+
+static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+	if (psci_ops.cpu_on)
+		return psci_ops.cpu_on(cpu_logical_map(cpu),
+					virt_to_idmap(&secondary_startup));
+	return -ENODEV;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+int psci_cpu_disable(unsigned int cpu)
+{
+	/* Fail early if we don't have CPU_OFF support */
+	if (!psci_ops.cpu_off)
+		return -EOPNOTSUPP;
+
+	/* Trusted OS will deny CPU_OFF */
+	if (psci_tos_resident_on(cpu))
+		return -EPERM;
+
+	return 0;
+}
+
+void __ref psci_cpu_die(unsigned int cpu)
+{
+	u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
+		    PSCI_0_2_POWER_STATE_TYPE_SHIFT;
+
+	if (psci_ops.cpu_off)
+		psci_ops.cpu_off(state);
+
+	/* We should never return */
+	panic("psci: cpu %d failed to shutdown\n", cpu);
+}
+
+int __ref psci_cpu_kill(unsigned int cpu)
+{
+	int err, i;
+
+	if (!psci_ops.affinity_info)
+		return 1;
+	/*
+	 * cpu_kill could race with cpu_die and we can
+	 * potentially end up declaring this cpu undead
+	 * while it is dying. So, try again a few times.
+	 */
+
+	for (i = 0; i < 10; i++) {
+		err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
+		if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
+			pr_info("CPU%d killed.\n", cpu);
+			return 1;
+		}
+
+		msleep(10);
+		pr_info("Retrying again to check for CPU kill\n");
+	}
+
+	pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
+			cpu, err);
+	/* Make platform_cpu_kill() fail. */
+	return 0;
+}
+
+#endif
+
+bool __init psci_smp_available(void)
+{
+	/* is cpu_on available at least? */
+	return (psci_ops.cpu_on != NULL);
+}
+
+struct smp_operations __initdata psci_smp_ops = {
+	.smp_boot_secondary	= psci_boot_secondary,
+#ifdef CONFIG_HOTPLUG_CPU
+	.cpu_disable		= psci_cpu_disable,
+	.cpu_die		= psci_cpu_die,
+	.cpu_kill		= psci_cpu_kill,
+#endif
+};
diff --git a/arch/arm/kernel/psci_smp.c b/arch/arm/kernel/psci_smp.c
deleted file mode 100644
index 61c04b0..0000000
--- a/arch/arm/kernel/psci_smp.c
+++ /dev/null
@@ -1,130 +0,0 @@
-/*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * Copyright (C) 2012 ARM Limited
- *
- * Author: Will Deacon <will.deacon@arm.com>
- */
-
-#include <linux/init.h>
-#include <linux/smp.h>
-#include <linux/of.h>
-#include <linux/delay.h>
-#include <linux/psci.h>
-
-#include <uapi/linux/psci.h>
-
-#include <asm/psci.h>
-#include <asm/smp_plat.h>
-
-/*
- * psci_smp assumes that the following is true about PSCI:
- *
- * cpu_suspend   Suspend the execution on a CPU
- * @state        we don't currently describe affinity levels, so just pass 0.
- * @entry_point  the first instruction to be executed on return
- * returns 0  success, < 0 on failure
- *
- * cpu_off       Power down a CPU
- * @state        we don't currently describe affinity levels, so just pass 0.
- * no return on successful call
- *
- * cpu_on        Power up a CPU
- * @cpuid        cpuid of target CPU, as from MPIDR
- * @entry_point  the first instruction to be executed on return
- * returns 0  success, < 0 on failure
- *
- * migrate       Migrate the context to a different CPU
- * @cpuid        cpuid of target CPU, as from MPIDR
- * returns 0  success, < 0 on failure
- *
- */
-
-extern void secondary_startup(void);
-
-static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
-{
-	if (psci_ops.cpu_on)
-		return psci_ops.cpu_on(cpu_logical_map(cpu),
-					virt_to_idmap(&secondary_startup));
-	return -ENODEV;
-}
-
-#ifdef CONFIG_HOTPLUG_CPU
-int psci_cpu_disable(unsigned int cpu)
-{
-	/* Fail early if we don't have CPU_OFF support */
-	if (!psci_ops.cpu_off)
-		return -EOPNOTSUPP;
-
-	/* Trusted OS will deny CPU_OFF */
-	if (psci_tos_resident_on(cpu))
-		return -EPERM;
-
-	return 0;
-}
-
-void __ref psci_cpu_die(unsigned int cpu)
-{
-	u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
-		    PSCI_0_2_POWER_STATE_TYPE_SHIFT;
-
-	if (psci_ops.cpu_off)
-		psci_ops.cpu_off(state);
-
-	/* We should never return */
-	panic("psci: cpu %d failed to shutdown\n", cpu);
-}
-
-int __ref psci_cpu_kill(unsigned int cpu)
-{
-	int err, i;
-
-	if (!psci_ops.affinity_info)
-		return 1;
-	/*
-	 * cpu_kill could race with cpu_die and we can
-	 * potentially end up declaring this cpu undead
-	 * while it is dying. So, try again a few times.
-	 */
-
-	for (i = 0; i < 10; i++) {
-		err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
-		if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
-			pr_info("CPU%d killed.\n", cpu);
-			return 1;
-		}
-
-		msleep(10);
-		pr_info("Retrying again to check for CPU kill\n");
-	}
-
-	pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
-			cpu, err);
-	/* Make platform_cpu_kill() fail. */
-	return 0;
-}
-
-#endif
-
-bool __init psci_smp_available(void)
-{
-	/* is cpu_on available at least? */
-	return (psci_ops.cpu_on != NULL);
-}
-
-struct smp_operations __initdata psci_smp_ops = {
-	.smp_boot_secondary	= psci_boot_secondary,
-#ifdef CONFIG_HOTPLUG_CPU
-	.cpu_disable		= psci_cpu_disable,
-	.cpu_die		= psci_cpu_die,
-	.cpu_kill		= psci_cpu_kill,
-#endif
-};
-- 
2.1.4

[RFC PATCH 2/3] arm: psci: enable PSCI on UP systems

[Jisheng Zhang]

This is to make calls like eg cpu_suspend can be made functional on UP too.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
 arch/arm/kernel/Makefile | 5 +----
 arch/arm/kernel/psci.c   | 2 ++
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index c57b2c0..2b1a60c 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -88,9 +88,6 @@ obj-$(CONFIG_DEBUG_LL)	+= debug.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 
 obj-$(CONFIG_ARM_VIRT_EXT)	+= hyp-stub.o
-ifeq ($(CONFIG_ARM_PSCI),y)
-obj-y				+= psci-call.o
-obj-$(CONFIG_SMP)		+= psci.o
-endif
+obj-$(CONFIG_ARM_PSCI)		+= psci-call.o psci.o
 
 extra-y := $(head-y) vmlinux.lds
diff --git a/arch/arm/kernel/psci.c b/arch/arm/kernel/psci.c
index 61c04b0..7f6ff02 100644
--- a/arch/arm/kernel/psci.c
+++ b/arch/arm/kernel/psci.c
@@ -47,6 +47,7 @@
  *
  */
 
+#ifdef CONFIG_SMP
 extern void secondary_startup(void);
 
 static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
@@ -128,3 +129,4 @@ struct smp_operations __initdata psci_smp_ops = {
 	.cpu_kill		= psci_cpu_kill,
 #endif
 };
+#endif
-- 
2.1.4

[RFC PATCH 3/3] arm: psci: add cpuidle_ops support

[Jisheng Zhang]

This patch implement cpuidle_ops using psci, the code is stolen from
arm64. Now we can use cpuidle-arm.c for both arm and arm64.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
 arch/arm/kernel/psci.c | 116 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 116 insertions(+)

diff --git a/arch/arm/kernel/psci.c b/arch/arm/kernel/psci.c
index 7f6ff02..7bf744d 100644
--- a/arch/arm/kernel/psci.c
+++ b/arch/arm/kernel/psci.c
@@ -13,16 +13,132 @@
  * Author: Will Deacon <will.deacon@arm.com>
  */
 
+#include <linux/cpuidle.h>
 #include <linux/init.h>
 #include <linux/smp.h>
 #include <linux/of.h>
 #include <linux/delay.h>
 #include <linux/psci.h>
+#include <linux/slab.h>
 
 #include <uapi/linux/psci.h>
 
+#include <asm/cpuidle.h>
 #include <asm/psci.h>
 #include <asm/smp_plat.h>
+#include <asm/suspend.h>
+
+#ifdef CONFIG_CPU_IDLE
+static bool psci_power_state_loses_context(u32 state)
+{
+	return state & PSCI_0_2_POWER_STATE_TYPE_MASK;
+}
+
+static bool psci_power_state_is_valid(u32 state)
+{
+	const u32 valid_mask = PSCI_0_2_POWER_STATE_ID_MASK |
+			       PSCI_0_2_POWER_STATE_TYPE_MASK |
+			       PSCI_0_2_POWER_STATE_AFFL_MASK;
+
+	return !(state & ~valid_mask);
+}
+
+static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
+
+static int __init cpu_psci_cpu_init_idle(struct device_node *cpu_node,
+					 int cpu)
+{
+	int i, ret, count = 0;
+	u32 *psci_states;
+	struct device_node *state_node;
+
+	/*
+	 * If the PSCI cpu_suspend function hook has not been initialized
+	 * idle states must not be enabled, so bail out
+	 */
+	if (!psci_ops.cpu_suspend)
+		return -EOPNOTSUPP;
+
+	/* Count idle states */
+	while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
+					      count))) {
+		count++;
+		of_node_put(state_node);
+	}
+
+	if (!count)
+		return -ENODEV;
+
+	psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
+	if (!psci_states)
+		return -ENOMEM;
+
+	for (i = 0; i < count; i++) {
+		u32 state;
+
+		state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
+
+		ret = of_property_read_u32(state_node,
+					   "arm,psci-suspend-param",
+					   &state);
+		if (ret) {
+			pr_warn(" * %s missing arm,psci-suspend-param property\n",
+				state_node->full_name);
+			of_node_put(state_node);
+			goto free_mem;
+		}
+
+		of_node_put(state_node);
+		pr_warn("psci-power-state %#x index %d\n", state, i);
+		if (!psci_power_state_is_valid(state)) {
+			pr_warn("Invalid PSCI power state %#x\n", state);
+			ret = -EINVAL;
+			goto free_mem;
+		}
+		psci_states[i] = state;
+	}
+	/* Idle states parsed correctly, initialize per-cpu pointer */
+	per_cpu(psci_power_state, cpu) = psci_states;
+	return 0;
+
+free_mem:
+	kfree(psci_states);
+	return ret;
+}
+
+static int psci_suspend_finisher(unsigned long index)
+{
+	u32 *state = __this_cpu_read(psci_power_state);
+
+	return psci_ops.cpu_suspend(state[index - 1],
+				    virt_to_phys(cpu_resume));
+}
+
+static int cpu_psci_cpu_suspend(int cpu, unsigned long index)
+{
+	int ret;
+	u32 *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 (!psci_power_state_loses_context(state[index - 1]))
+		ret = psci_ops.cpu_suspend(state[index - 1], 0);
+	else
+		ret = cpu_suspend(index, psci_suspend_finisher);
+
+	return ret;
+}
+
+static struct cpuidle_ops psci_cpuidle_ops __initdata = {
+	.suspend = cpu_psci_cpu_suspend,
+	.init = cpu_psci_cpu_init_idle,
+};
+CPUIDLE_METHOD_OF_DECLARE(psci_idle, "psci", &psci_cpuidle_ops);
+#endif
 
 /*
  * psci_smp assumes that the following is true about PSCI:
-- 
2.1.4

Re: [RFC PATCH 1/3] arm: psci: rename psci_smp.c to psci.c

[Daniel Lezcano]

On 07/04/2015 03:01 PM, Jisheng Zhang wrote:
> This will prepare for next commit to enable PSCI for UP systems so that
> calls like cpu_suspend can be made functional on UP too.
>
> Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
> ---
>   arch/arm/kernel/Makefile   |   2 +-
>   arch/arm/kernel/psci.c     | 130 +++++++++++++++++++++++++++++++++++++++++++++
>   arch/arm/kernel/psci_smp.c | 130 ---------------------------------------------
>   3 files changed, 131 insertions(+), 131 deletions(-)
>   create mode 100644 arch/arm/kernel/psci.c
>   delete mode 100644 arch/arm/kernel/psci_smp.c

When you move or rename a file, use the -M option with git when sending 
the email. Instead of providing a big diff file, it will just annotate 
the renaming.



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Re: [RFC PATCH 1/3] arm: psci: rename psci_smp.c to psci.c

[Jisheng Zhang]

On Mon, 6 Jul 2015 11:06:22 +0200
Daniel Lezcano <daniel.lezcano@linaro.org> wrote:

> On 07/04/2015 03:01 PM, Jisheng Zhang wrote:
> > This will prepare for next commit to enable PSCI for UP systems so that
> > calls like cpu_suspend can be made functional on UP too.
> >
> > Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
> > ---
> >   arch/arm/kernel/Makefile   |   2 +-
> >   arch/arm/kernel/psci.c     | 130 +++++++++++++++++++++++++++++++++++++++++++++
> >   arch/arm/kernel/psci_smp.c | 130 ---------------------------------------------
> >   3 files changed, 131 insertions(+), 131 deletions(-)
> >   create mode 100644 arch/arm/kernel/psci.c
> >   delete mode 100644 arch/arm/kernel/psci_smp.c
> 
> When you move or rename a file, use the -M option with git when sending 
> the email. Instead of providing a big diff file, it will just annotate 
> the renaming.

Thanks for the kindly remind and tips, I didn't know this before. Will take
care that in the future.

Thanks a lot,
Jisheng

Re: [RFC PATCH 2/3] arm: psci: enable PSCI on UP systems

[Lorenzo Pieralisi]

On Sat, Jul 04, 2015 at 02:01:49PM +0100, Jisheng Zhang wrote:
> This is to make calls like eg cpu_suspend can be made functional on UP too.
> 
> Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
> ---
>  arch/arm/kernel/Makefile | 5 +----
>  arch/arm/kernel/psci.c   | 2 ++
>  2 files changed, 3 insertions(+), 4 deletions(-)

You will have to rewrite the commit log (mostly because PSCI CPU suspend
will move to drivers/firmware so it will become stale, I know what you
mean but it might be unclear to others so please improve it).

Patch (and intent) seems fine though:

Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

> diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
> index c57b2c0..2b1a60c 100644
> --- a/arch/arm/kernel/Makefile
> +++ b/arch/arm/kernel/Makefile
> @@ -88,9 +88,6 @@ obj-$(CONFIG_DEBUG_LL)	+= debug.o
>  obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
>  
>  obj-$(CONFIG_ARM_VIRT_EXT)	+= hyp-stub.o
> -ifeq ($(CONFIG_ARM_PSCI),y)
> -obj-y				+= psci-call.o
> -obj-$(CONFIG_SMP)		+= psci.o
> -endif
> +obj-$(CONFIG_ARM_PSCI)		+= psci-call.o psci.o
>  
>  extra-y := $(head-y) vmlinux.lds
> diff --git a/arch/arm/kernel/psci.c b/arch/arm/kernel/psci.c
> index 61c04b0..7f6ff02 100644
> --- a/arch/arm/kernel/psci.c
> +++ b/arch/arm/kernel/psci.c
> @@ -47,6 +47,7 @@
>   *
>   */
>  
> +#ifdef CONFIG_SMP
>  extern void secondary_startup(void);
>  
>  static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
> @@ -128,3 +129,4 @@ struct smp_operations __initdata psci_smp_ops = {
>  	.cpu_kill		= psci_cpu_kill,
>  #endif
>  };
> +#endif
> -- 
> 2.1.4
> 

Re: [RFC PATCH 3/3] arm: psci: add cpuidle_ops support

[Lorenzo Pieralisi]

On Sat, Jul 04, 2015 at 02:01:50PM +0100, Jisheng Zhang wrote:
> This patch implement cpuidle_ops using psci, the code is stolen from
> arm64. Now we can use cpuidle-arm.c for both arm and arm64.

You mean cpuidle-arm.c with PSCI back-end. You will have to rewrite
the commit log anyway since this patch will be significantly trimmed,
see below.

> Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
> ---
>  arch/arm/kernel/psci.c | 116 +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 116 insertions(+)
> 
> diff --git a/arch/arm/kernel/psci.c b/arch/arm/kernel/psci.c
> index 7f6ff02..7bf744d 100644
> --- a/arch/arm/kernel/psci.c
> +++ b/arch/arm/kernel/psci.c
> @@ -13,16 +13,132 @@
>   * Author: Will Deacon <will.deacon@arm.com>
>   */
>  
> +#include <linux/cpuidle.h>
>  #include <linux/init.h>
>  #include <linux/smp.h>
>  #include <linux/of.h>
>  #include <linux/delay.h>
>  #include <linux/psci.h>
> +#include <linux/slab.h>
>  
>  #include <uapi/linux/psci.h>
>  
> +#include <asm/cpuidle.h>
>  #include <asm/psci.h>
>  #include <asm/smp_plat.h>
> +#include <asm/suspend.h>
> +
> +#ifdef CONFIG_CPU_IDLE
> +static bool psci_power_state_loses_context(u32 state)
> +{
> +	return state & PSCI_0_2_POWER_STATE_TYPE_MASK;
> +}
> +
> +static bool psci_power_state_is_valid(u32 state)
> +{
> +	const u32 valid_mask = PSCI_0_2_POWER_STATE_ID_MASK |
> +			       PSCI_0_2_POWER_STATE_TYPE_MASK |
> +			       PSCI_0_2_POWER_STATE_AFFL_MASK;
> +
> +	return !(state & ~valid_mask);
> +}

Already moved these helpers to drivers/firmware:

http://lists.infradead.org/pipermail/linux-arm-kernel/2015-May/347355.html

> +
> +static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
> +
> +static int __init cpu_psci_cpu_init_idle(struct device_node *cpu_node,
> +					 int cpu)
> +{
> +	int i, ret, count = 0;
> +	u32 *psci_states;
> +	struct device_node *state_node;
> +
> +	/*
> +	 * If the PSCI cpu_suspend function hook has not been initialized
> +	 * idle states must not be enabled, so bail out
> +	 */
> +	if (!psci_ops.cpu_suspend)
> +		return -EOPNOTSUPP;
> +
> +	/* Count idle states */
> +	while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
> +					      count))) {
> +		count++;
> +		of_node_put(state_node);
> +	}
> +
> +	if (!count)
> +		return -ENODEV;
> +
> +	psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
> +	if (!psci_states)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < count; i++) {
> +		u32 state;
> +
> +		state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
> +
> +		ret = of_property_read_u32(state_node,
> +					   "arm,psci-suspend-param",
> +					   &state);
> +		if (ret) {
> +			pr_warn(" * %s missing arm,psci-suspend-param property\n",
> +				state_node->full_name);
> +			of_node_put(state_node);
> +			goto free_mem;
> +		}
> +
> +		of_node_put(state_node);
> +		pr_warn("psci-power-state %#x index %d\n", state, i);
> +		if (!psci_power_state_is_valid(state)) {
> +			pr_warn("Invalid PSCI power state %#x\n", state);
> +			ret = -EINVAL;
> +			goto free_mem;
> +		}
> +		psci_states[i] = state;
> +	}
> +	/* Idle states parsed correctly, initialize per-cpu pointer */
> +	per_cpu(psci_power_state, cpu) = psci_states;
> +	return 0;
> +
> +free_mem:
> +	kfree(psci_states);
> +	return ret;
> +}
> +
> +static int psci_suspend_finisher(unsigned long index)
> +{
> +	u32 *state = __this_cpu_read(psci_power_state);
> +
> +	return psci_ops.cpu_suspend(state[index - 1],
> +				    virt_to_phys(cpu_resume));
> +}
> +
> +static int cpu_psci_cpu_suspend(int cpu, unsigned long index)
> +{
> +	int ret;
> +	u32 *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 (!psci_power_state_loses_context(state[index - 1]))
> +		ret = psci_ops.cpu_suspend(state[index - 1], 0);
> +	else
> +		ret = cpu_suspend(index, psci_suspend_finisher);
> +
> +	return ret;
> +}

Code above is arch agnostic and should be moved out of arch/arm (and
arm64).

Can you put together a patch to do it or you want me to do it ?

> +static struct cpuidle_ops psci_cpuidle_ops __initdata = {
> +	.suspend = cpu_psci_cpu_suspend,
> +	.init = cpu_psci_cpu_init_idle,
> +};
> +CPUIDLE_METHOD_OF_DECLARE(psci_idle, "psci", &psci_cpuidle_ops);
> +#endif

This is fine and should stay in arch/arm.

Thanks,
Lorenzo

Re: [RFC PATCH 3/3] arm: psci: add cpuidle_ops support

[Jisheng Zhang]

Dear Lorenzo,

On Tue, 7 Jul 2015 15:23:45 +0100
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> wrote:

> On Sat, Jul 04, 2015 at 02:01:50PM +0100, Jisheng Zhang wrote:
> > This patch implement cpuidle_ops using psci, the code is stolen from
> > arm64. Now we can use cpuidle-arm.c for both arm and arm64.
> 
> You mean cpuidle-arm.c with PSCI back-end. You will have to rewrite
> the commit log anyway since this patch will be significantly trimmed,
> see below.

Will do, thanks for the suggestion.

> 
> > Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
> > ---
> >  arch/arm/kernel/psci.c | 116 +++++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 116 insertions(+)
> > 
> > diff --git a/arch/arm/kernel/psci.c b/arch/arm/kernel/psci.c
> > index 7f6ff02..7bf744d 100644
> > --- a/arch/arm/kernel/psci.c
> > +++ b/arch/arm/kernel/psci.c
> > @@ -13,16 +13,132 @@
> >   * Author: Will Deacon <will.deacon@arm.com>
> >   */
> >  
> > +#include <linux/cpuidle.h>
> >  #include <linux/init.h>
> >  #include <linux/smp.h>
> >  #include <linux/of.h>
> >  #include <linux/delay.h>
> >  #include <linux/psci.h>
> > +#include <linux/slab.h>
> >  
> >  #include <uapi/linux/psci.h>
> >  
> > +#include <asm/cpuidle.h>
> >  #include <asm/psci.h>
> >  #include <asm/smp_plat.h>
> > +#include <asm/suspend.h>
> > +
> > +#ifdef CONFIG_CPU_IDLE
> > +static bool psci_power_state_loses_context(u32 state)
> > +{
> > +	return state & PSCI_0_2_POWER_STATE_TYPE_MASK;
> > +}
> > +
> > +static bool psci_power_state_is_valid(u32 state)
> > +{
> > +	const u32 valid_mask = PSCI_0_2_POWER_STATE_ID_MASK |
> > +			       PSCI_0_2_POWER_STATE_TYPE_MASK |
> > +			       PSCI_0_2_POWER_STATE_AFFL_MASK;
> > +
> > +	return !(state & ~valid_mask);
> > +}
> 
> Already moved these helpers to drivers/firmware:
> 
> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-May/347355.html
> 
> > +
> > +static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
> > +
> > +static int __init cpu_psci_cpu_init_idle(struct device_node *cpu_node,
> > +					 int cpu)
> > +{
> > +	int i, ret, count = 0;
> > +	u32 *psci_states;
> > +	struct device_node *state_node;
> > +
> > +	/*
> > +	 * If the PSCI cpu_suspend function hook has not been initialized
> > +	 * idle states must not be enabled, so bail out
> > +	 */
> > +	if (!psci_ops.cpu_suspend)
> > +		return -EOPNOTSUPP;
> > +
> > +	/* Count idle states */
> > +	while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
> > +					      count))) {
> > +		count++;
> > +		of_node_put(state_node);
> > +	}
> > +
> > +	if (!count)
> > +		return -ENODEV;
> > +
> > +	psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
> > +	if (!psci_states)
> > +		return -ENOMEM;
> > +
> > +	for (i = 0; i < count; i++) {
> > +		u32 state;
> > +
> > +		state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
> > +
> > +		ret = of_property_read_u32(state_node,
> > +					   "arm,psci-suspend-param",
> > +					   &state);
> > +		if (ret) {
> > +			pr_warn(" * %s missing arm,psci-suspend-param property\n",
> > +				state_node->full_name);
> > +			of_node_put(state_node);
> > +			goto free_mem;
> > +		}
> > +
> > +		of_node_put(state_node);
> > +		pr_warn("psci-power-state %#x index %d\n", state, i);
> > +		if (!psci_power_state_is_valid(state)) {
> > +			pr_warn("Invalid PSCI power state %#x\n", state);
> > +			ret = -EINVAL;
> > +			goto free_mem;
> > +		}
> > +		psci_states[i] = state;
> > +	}
> > +	/* Idle states parsed correctly, initialize per-cpu pointer */
> > +	per_cpu(psci_power_state, cpu) = psci_states;
> > +	return 0;
> > +
> > +free_mem:
> > +	kfree(psci_states);
> > +	return ret;
> > +}
> > +
> > +static int psci_suspend_finisher(unsigned long index)
> > +{
> > +	u32 *state = __this_cpu_read(psci_power_state);
> > +
> > +	return psci_ops.cpu_suspend(state[index - 1],
> > +				    virt_to_phys(cpu_resume));
> > +}
> > +
> > +static int cpu_psci_cpu_suspend(int cpu, unsigned long index)
> > +{
> > +	int ret;
> > +	u32 *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 (!psci_power_state_loses_context(state[index - 1]))
> > +		ret = psci_ops.cpu_suspend(state[index - 1], 0);
> > +	else
> > +		ret = cpu_suspend(index, psci_suspend_finisher);
> > +
> > +	return ret;
> > +}
> 
> Code above is arch agnostic and should be moved out of arch/arm (and
> arm64).

Got it. the remaining issue is cpuidle_ops.suspend prototype. Does it make
sense to change it from

int (*suspend)(int cpu, unsigned long arg);

to

int (*suspend)(unsigned long arg);

It seems that the to-be-suspended cpu is always the calling cpu itself.

Anyway I won't change the prototype but make a simple glue instead in the next
for patch for review.

> 
> Can you put together a patch to do it or you want me to do it ?
> 
> > +static struct cpuidle_ops psci_cpuidle_ops __initdata = {
> > +	.suspend = cpu_psci_cpu_suspend,
> > +	.init = cpu_psci_cpu_init_idle,
> > +};
> > +CPUIDLE_METHOD_OF_DECLARE(psci_idle, "psci", &psci_cpuidle_ops);
> > +#endif
> 
> This is fine and should stay in arch/arm.

Thanks a lot for the review and tips, I'll cook newer patches for review.

Thanks,
Jisheng