|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [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@xxxxxxx>
Acked-by: Nicolas Pitre <nico@xxxxxxxxxx>
> ---
> 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@xxxxxxx>
> + */
> +
> +#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 mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |