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Will Deacon

2012-Dec-18 17:53 UTC

[PATCH v3 4/6] ARM: psci: add support for PSCI invocations from the kernel

This patch adds support for the Power State Coordination Interface
defined by ARM, allowing Linux to request CPU-centric power-management
operations from firmware implementing the PSCI protocol.

Signed-off-by: Will Deacon <will.deacon@arm.com>
---
 arch/arm/Kconfig            |  10 +++
 arch/arm/include/asm/psci.h |  36 ++++++++
 arch/arm/kernel/Makefile    |   1 +
 arch/arm/kernel/psci.c      | 211 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 258 insertions(+)
 create mode 100644 arch/arm/include/asm/psci.h
 create mode 100644 arch/arm/kernel/psci.c

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 8c83d98..80d54b8 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1617,6 +1617,16 @@ config HOTPLUG_CPU
 	  Say Y here to experiment with turning CPUs off and on.  CPUs
 	  can be controlled through /sys/devices/system/cpu.
 
+config ARM_PSCI
+	bool "Support for the ARM Power State Coordination Interface (PSCI)"
+	depends on CPU_V7
+	help
+	  Say Y here if you want Linux to communicate with system firmware
+	  implementing the PSCI specification for CPU-centric power
+	  management operations described in ARM document number ARM DEN
+	  0022A ("Power State Coordination Interface System Software on
+	  ARM processors").
+
 config LOCAL_TIMERS
 	bool "Use local timer interrupts"
 	depends on SMP
diff --git a/arch/arm/include/asm/psci.h b/arch/arm/include/asm/psci.h
new file mode 100644
index 0000000..ce0dbe7
--- /dev/null
+++ b/arch/arm/include/asm/psci.h
@@ -0,0 +1,36 @@
+/*
+ * 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
+ */
+
+#ifndef __ASM_ARM_PSCI_H
+#define __ASM_ARM_PSCI_H
+
+#define PSCI_POWER_STATE_TYPE_STANDBY		0
+#define PSCI_POWER_STATE_TYPE_POWER_DOWN	1
+
+struct psci_power_state {
+	u16	id;
+	u8	type;
+	u8	affinity_level;
+};
+
+struct psci_operations {
+	int (*cpu_suspend)(struct psci_power_state state,
+			   unsigned long entry_point);
+	int (*cpu_off)(struct psci_power_state state);
+	int (*cpu_on)(unsigned long cpuid, unsigned long entry_point);
+	int (*migrate)(unsigned long cpuid);
+};
+
+extern struct psci_operations psci_ops;
+
+#endif /* __ASM_ARM_PSCI_H */
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 5bbec7b..5f3338e 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -82,5 +82,6 @@ obj-$(CONFIG_DEBUG_LL)	+= debug.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 
 obj-$(CONFIG_ARM_VIRT_EXT)	+= hyp-stub.o
+obj-$(CONFIG_ARM_PSCI)		+= psci.o
 
 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..3653164
--- /dev/null
+++ b/arch/arm/kernel/psci.c
@@ -0,0 +1,211 @@
+/*
+ * 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>
+ */
+
+#define pr_fmt(fmt) "psci: " fmt
+
+#include <linux/init.h>
+#include <linux/of.h>
+
+#include <asm/compiler.h>
+#include <asm/errno.h>
+#include <asm/opcodes-sec.h>
+#include <asm/opcodes-virt.h>
+#include <asm/psci.h>
+
+struct psci_operations psci_ops;
+
+static int (*invoke_psci_fn)(u32, u32, u32, u32);
+
+enum psci_function {
+	PSCI_FN_CPU_SUSPEND,
+	PSCI_FN_CPU_ON,
+	PSCI_FN_CPU_OFF,
+	PSCI_FN_MIGRATE,
+	PSCI_FN_MAX,
+};
+
+static u32 psci_function_id[PSCI_FN_MAX];
+
+#define PSCI_RET_SUCCESS		0
+#define PSCI_RET_EOPNOTSUPP		-1
+#define PSCI_RET_EINVAL			-2
+#define PSCI_RET_EPERM			-3
+
+static int psci_to_linux_errno(int errno)
+{
+	switch (errno) {
+	case PSCI_RET_SUCCESS:
+		return 0;
+	case PSCI_RET_EOPNOTSUPP:
+		return -EOPNOTSUPP;
+	case PSCI_RET_EINVAL:
+		return -EINVAL;
+	case PSCI_RET_EPERM:
+		return -EPERM;
+	};
+
+	return -EINVAL;
+}
+
+#define PSCI_POWER_STATE_ID_MASK	0xffff
+#define PSCI_POWER_STATE_ID_SHIFT	0
+#define PSCI_POWER_STATE_TYPE_MASK	0x1
+#define PSCI_POWER_STATE_TYPE_SHIFT	16
+#define PSCI_POWER_STATE_AFFL_MASK	0x3
+#define PSCI_POWER_STATE_AFFL_SHIFT	24
+
+static u32 psci_power_state_pack(struct psci_power_state state)
+{
+	return	((state.id & PSCI_POWER_STATE_ID_MASK)
+			<< PSCI_POWER_STATE_ID_SHIFT)	|
+		((state.type & PSCI_POWER_STATE_TYPE_MASK)
+			<< PSCI_POWER_STATE_TYPE_SHIFT)	|
+		((state.affinity_level & PSCI_POWER_STATE_AFFL_MASK)
+			<< PSCI_POWER_STATE_AFFL_SHIFT);
+}
+
+/*
+ * The following two functions are invoked via the invoke_psci_fn pointer
+ * and will not be inlined, allowing us to piggyback on the AAPCS.
+ */
+static noinline int __invoke_psci_fn_hvc(u32 function_id, u32 arg0, u32 arg1,
+					 u32 arg2)
+{
+	asm volatile(
+			__asmeq("%0", "r0")
+			__asmeq("%1", "r1")
+			__asmeq("%2", "r2")
+			__asmeq("%3", "r3")
+			__HVC(0)
+		: "+r" (function_id)
+		: "r" (arg0), "r" (arg1), "r" (arg2));
+
+	return function_id;
+}
+
+static noinline int __invoke_psci_fn_smc(u32 function_id, u32 arg0, u32 arg1,
+					 u32 arg2)
+{
+	asm volatile(
+			__asmeq("%0", "r0")
+			__asmeq("%1", "r1")
+			__asmeq("%2", "r2")
+			__asmeq("%3", "r3")
+			__SMC(0)
+		: "+r" (function_id)
+		: "r" (arg0), "r" (arg1), "r" (arg2));
+
+	return function_id;
+}
+
+static int psci_cpu_suspend(struct psci_power_state state,
+			    unsigned long entry_point)
+{
+	int err;
+	u32 fn, power_state;
+
+	fn = psci_function_id[PSCI_FN_CPU_SUSPEND];
+	power_state = psci_power_state_pack(state);
+	err = invoke_psci_fn(fn, power_state, entry_point, 0);
+	return psci_to_linux_errno(err);
+}
+
+static int psci_cpu_off(struct psci_power_state state)
+{
+	int err;
+	u32 fn, power_state;
+
+	fn = psci_function_id[PSCI_FN_CPU_OFF];
+	power_state = psci_power_state_pack(state);
+	err = invoke_psci_fn(fn, power_state, 0, 0);
+	return psci_to_linux_errno(err);
+}
+
+static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
+{
+	int err;
+	u32 fn;
+
+	fn = psci_function_id[PSCI_FN_CPU_ON];
+	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
+	return psci_to_linux_errno(err);
+}
+
+static int psci_migrate(unsigned long cpuid)
+{
+	int err;
+	u32 fn;
+
+	fn = psci_function_id[PSCI_FN_MIGRATE];
+	err = invoke_psci_fn(fn, cpuid, 0, 0);
+	return psci_to_linux_errno(err);
+}
+
+static const struct of_device_id psci_of_match[] __initconst = {
+	{ .compatible = "arm,psci",	},
+	{},
+};
+
+static int __init psci_init(void)
+{
+	struct device_node *np;
+	const char *method;
+	u32 id;
+
+	np = of_find_matching_node(NULL, psci_of_match);
+	if (!np)
+		return 0;
+
+	pr_info("probing function IDs from device-tree\n");
+
+	if (of_property_read_string(np, "method", &method)) {
+		pr_warning("missing \"method\" property\n");
+		goto out_put_node;
+	}
+
+	if (!strcmp("hvc", method)) {
+		invoke_psci_fn = __invoke_psci_fn_hvc;
+	} else if (!strcmp("smc", method)) {
+		invoke_psci_fn = __invoke_psci_fn_smc;
+	} else {
+		pr_warning("invalid \"method\" property: %s\n", method);
+		goto out_put_node;
+	}
+
+	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
+		psci_function_id[PSCI_FN_CPU_SUSPEND] = id;
+		psci_ops.cpu_suspend = psci_cpu_suspend;
+	}
+
+	if (!of_property_read_u32(np, "cpu_off", &id)) {
+		psci_function_id[PSCI_FN_CPU_OFF] = id;
+		psci_ops.cpu_off = psci_cpu_off;
+	}
+
+	if (!of_property_read_u32(np, "cpu_on", &id)) {
+		psci_function_id[PSCI_FN_CPU_ON] = id;
+		psci_ops.cpu_on = psci_cpu_on;
+	}
+
+	if (!of_property_read_u32(np, "migrate", &id)) {
+		psci_function_id[PSCI_FN_MIGRATE] = id;
+		psci_ops.migrate = psci_migrate;
+	}
+
+out_put_node:
+	of_node_put(np);
+	return 0;
+}
+early_initcall(psci_init);
-- 
1.8.0

Nicolas Pitre

2012-Dec-19 04:16 UTC

head link

Re: [PATCH v3 4/6] ARM: psci: add support for PSCI invocations from the kernel

On Tue, 18 Dec 2012, Will Deacon wrote:
> This patch adds support for the Power State Coordination Interface
> defined by ARM, allowing Linux to request CPU-centric power-management
> operations from firmware implementing the PSCI protocol.
> 
> Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>

> ---
>  arch/arm/Kconfig            |  10 +++
>  arch/arm/include/asm/psci.h |  36 ++++++++
>  arch/arm/kernel/Makefile    |   1 +
>  arch/arm/kernel/psci.c      | 211
++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 258 insertions(+)
>  create mode 100644 arch/arm/include/asm/psci.h
>  create mode 100644 arch/arm/kernel/psci.c
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 8c83d98..80d54b8 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1617,6 +1617,16 @@ config HOTPLUG_CPU
>  	  Say Y here to experiment with turning CPUs off and on.  CPUs
>  	  can be controlled through /sys/devices/system/cpu.
>  
> +config ARM_PSCI
> +	bool "Support for the ARM Power State Coordination Interface
(PSCI)"
> +	depends on CPU_V7
> +	help
> +	  Say Y here if you want Linux to communicate with system firmware
> +	  implementing the PSCI specification for CPU-centric power
> +	  management operations described in ARM document number ARM DEN
> +	  0022A ("Power State Coordination Interface System Software on
> +	  ARM processors").
> +
>  config LOCAL_TIMERS
>  	bool "Use local timer interrupts"
>  	depends on SMP
> diff --git a/arch/arm/include/asm/psci.h b/arch/arm/include/asm/psci.h
> new file mode 100644
> index 0000000..ce0dbe7
> --- /dev/null
> +++ b/arch/arm/include/asm/psci.h
> @@ -0,0 +1,36 @@
> +/*
> + * 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
> + */
> +
> +#ifndef __ASM_ARM_PSCI_H
> +#define __ASM_ARM_PSCI_H
> +
> +#define PSCI_POWER_STATE_TYPE_STANDBY		0
> +#define PSCI_POWER_STATE_TYPE_POWER_DOWN	1
> +
> +struct psci_power_state {
> +	u16	id;
> +	u8	type;
> +	u8	affinity_level;
> +};
> +
> +struct psci_operations {
> +	int (*cpu_suspend)(struct psci_power_state state,
> +			   unsigned long entry_point);
> +	int (*cpu_off)(struct psci_power_state state);
> +	int (*cpu_on)(unsigned long cpuid, unsigned long entry_point);
> +	int (*migrate)(unsigned long cpuid);
> +};
> +
> +extern struct psci_operations psci_ops;
> +
> +#endif /* __ASM_ARM_PSCI_H */
> diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
> index 5bbec7b..5f3338e 100644
> --- a/arch/arm/kernel/Makefile
> +++ b/arch/arm/kernel/Makefile
> @@ -82,5 +82,6 @@ obj-$(CONFIG_DEBUG_LL)	+= debug.o
>  obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
>  
>  obj-$(CONFIG_ARM_VIRT_EXT)	+= hyp-stub.o
> +obj-$(CONFIG_ARM_PSCI)		+= psci.o
>  
>  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..3653164
> --- /dev/null
> +++ b/arch/arm/kernel/psci.c
> @@ -0,0 +1,211 @@
> +/*
> + * 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>
> + */
> +
> +#define pr_fmt(fmt) "psci: " fmt
> +
> +#include <linux/init.h>
> +#include <linux/of.h>
> +
> +#include <asm/compiler.h>
> +#include <asm/errno.h>
> +#include <asm/opcodes-sec.h>
> +#include <asm/opcodes-virt.h>
> +#include <asm/psci.h>
> +
> +struct psci_operations psci_ops;
> +
> +static int (*invoke_psci_fn)(u32, u32, u32, u32);
> +
> +enum psci_function {
> +	PSCI_FN_CPU_SUSPEND,
> +	PSCI_FN_CPU_ON,
> +	PSCI_FN_CPU_OFF,
> +	PSCI_FN_MIGRATE,
> +	PSCI_FN_MAX,
> +};
> +
> +static u32 psci_function_id[PSCI_FN_MAX];
> +
> +#define PSCI_RET_SUCCESS		0
> +#define PSCI_RET_EOPNOTSUPP		-1
> +#define PSCI_RET_EINVAL			-2
> +#define PSCI_RET_EPERM			-3
> +
> +static int psci_to_linux_errno(int errno)
> +{
> +	switch (errno) {
> +	case PSCI_RET_SUCCESS:
> +		return 0;
> +	case PSCI_RET_EOPNOTSUPP:
> +		return -EOPNOTSUPP;
> +	case PSCI_RET_EINVAL:
> +		return -EINVAL;
> +	case PSCI_RET_EPERM:
> +		return -EPERM;
> +	};
> +
> +	return -EINVAL;
> +}
> +
> +#define PSCI_POWER_STATE_ID_MASK	0xffff
> +#define PSCI_POWER_STATE_ID_SHIFT	0
> +#define PSCI_POWER_STATE_TYPE_MASK	0x1
> +#define PSCI_POWER_STATE_TYPE_SHIFT	16
> +#define PSCI_POWER_STATE_AFFL_MASK	0x3
> +#define PSCI_POWER_STATE_AFFL_SHIFT	24
> +
> +static u32 psci_power_state_pack(struct psci_power_state state)
> +{
> +	return	((state.id & PSCI_POWER_STATE_ID_MASK)
> +			<< PSCI_POWER_STATE_ID_SHIFT)	|
> +		((state.type & PSCI_POWER_STATE_TYPE_MASK)
> +			<< PSCI_POWER_STATE_TYPE_SHIFT)	|
> +		((state.affinity_level & PSCI_POWER_STATE_AFFL_MASK)
> +			<< PSCI_POWER_STATE_AFFL_SHIFT);
> +}
> +
> +/*
> + * The following two functions are invoked via the invoke_psci_fn pointer
> + * and will not be inlined, allowing us to piggyback on the AAPCS.
> + */
> +static noinline int __invoke_psci_fn_hvc(u32 function_id, u32 arg0, u32
arg1,
> +					 u32 arg2)
> +{
> +	asm volatile(
> +			__asmeq("%0", "r0")
> +			__asmeq("%1", "r1")
> +			__asmeq("%2", "r2")
> +			__asmeq("%3", "r3")
> +			__HVC(0)
> +		: "+r" (function_id)
> +		: "r" (arg0), "r" (arg1), "r" (arg2));
> +
> +	return function_id;
> +}
> +
> +static noinline int __invoke_psci_fn_smc(u32 function_id, u32 arg0, u32
arg1,
> +					 u32 arg2)
> +{
> +	asm volatile(
> +			__asmeq("%0", "r0")
> +			__asmeq("%1", "r1")
> +			__asmeq("%2", "r2")
> +			__asmeq("%3", "r3")
> +			__SMC(0)
> +		: "+r" (function_id)
> +		: "r" (arg0), "r" (arg1), "r" (arg2));
> +
> +	return function_id;
> +}
> +
> +static int psci_cpu_suspend(struct psci_power_state state,
> +			    unsigned long entry_point)
> +{
> +	int err;
> +	u32 fn, power_state;
> +
> +	fn = psci_function_id[PSCI_FN_CPU_SUSPEND];
> +	power_state = psci_power_state_pack(state);
> +	err = invoke_psci_fn(fn, power_state, entry_point, 0);
> +	return psci_to_linux_errno(err);
> +}
> +
> +static int psci_cpu_off(struct psci_power_state state)
> +{
> +	int err;
> +	u32 fn, power_state;
> +
> +	fn = psci_function_id[PSCI_FN_CPU_OFF];
> +	power_state = psci_power_state_pack(state);
> +	err = invoke_psci_fn(fn, power_state, 0, 0);
> +	return psci_to_linux_errno(err);
> +}
> +
> +static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
> +{
> +	int err;
> +	u32 fn;
> +
> +	fn = psci_function_id[PSCI_FN_CPU_ON];
> +	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
> +	return psci_to_linux_errno(err);
> +}
> +
> +static int psci_migrate(unsigned long cpuid)
> +{
> +	int err;
> +	u32 fn;
> +
> +	fn = psci_function_id[PSCI_FN_MIGRATE];
> +	err = invoke_psci_fn(fn, cpuid, 0, 0);
> +	return psci_to_linux_errno(err);
> +}
> +
> +static const struct of_device_id psci_of_match[] __initconst = {
> +	{ .compatible = "arm,psci",	},
> +	{},
> +};
> +
> +static int __init psci_init(void)
> +{
> +	struct device_node *np;
> +	const char *method;
> +	u32 id;
> +
> +	np = of_find_matching_node(NULL, psci_of_match);
> +	if (!np)
> +		return 0;
> +
> +	pr_info("probing function IDs from device-tree\n");
> +
> +	if (of_property_read_string(np, "method", &method)) {
> +		pr_warning("missing \"method\" property\n");
> +		goto out_put_node;
> +	}
> +
> +	if (!strcmp("hvc", method)) {
> +		invoke_psci_fn = __invoke_psci_fn_hvc;
> +	} else if (!strcmp("smc", method)) {
> +		invoke_psci_fn = __invoke_psci_fn_smc;
> +	} else {
> +		pr_warning("invalid \"method\" property: %s\n",
method);
> +		goto out_put_node;
> +	}
> +
> +	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
> +		psci_function_id[PSCI_FN_CPU_SUSPEND] = id;
> +		psci_ops.cpu_suspend = psci_cpu_suspend;
> +	}
> +
> +	if (!of_property_read_u32(np, "cpu_off", &id)) {
> +		psci_function_id[PSCI_FN_CPU_OFF] = id;
> +		psci_ops.cpu_off = psci_cpu_off;
> +	}
> +
> +	if (!of_property_read_u32(np, "cpu_on", &id)) {
> +		psci_function_id[PSCI_FN_CPU_ON] = id;
> +		psci_ops.cpu_on = psci_cpu_on;
> +	}
> +
> +	if (!of_property_read_u32(np, "migrate", &id)) {
> +		psci_function_id[PSCI_FN_MIGRATE] = id;
> +		psci_ops.migrate = psci_migrate;
> +	}
> +
> +out_put_node:
> +	of_node_put(np);
> +	return 0;
> +}
> +early_initcall(psci_init);
> -- 
> 1.8.0
>

Xen devel - Dec 2012 - [PATCH v3 4/6] ARM: psci: add support for PSCI invocations from the kernel

[PATCH v3 4/6] ARM: psci: add support for PSCI invocations from the kernel

Re: [PATCH v3 4/6] ARM: psci: add support for PSCI invocations from the kernel