Commit 2bdd424f authored by Will Deacon's avatar Will Deacon

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.
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarNicolas Pitre <nico@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 65397edf
...@@ -1620,6 +1620,16 @@ config HOTPLUG_CPU ...@@ -1620,6 +1620,16 @@ config HOTPLUG_CPU
Say Y here to experiment with turning CPUs off and on. CPUs Say Y here to experiment with turning CPUs off and on. CPUs
can be controlled through /sys/devices/system/cpu. 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 config LOCAL_TIMERS
bool "Use local timer interrupts" bool "Use local timer interrupts"
depends on SMP depends on SMP
......
/*
* 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 */
...@@ -82,5 +82,6 @@ obj-$(CONFIG_DEBUG_LL) += debug.o ...@@ -82,5 +82,6 @@ obj-$(CONFIG_DEBUG_LL) += debug.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
obj-$(CONFIG_ARM_VIRT_EXT) += hyp-stub.o obj-$(CONFIG_ARM_VIRT_EXT) += hyp-stub.o
obj-$(CONFIG_ARM_PSCI) += psci.o
extra-y := $(head-y) vmlinux.lds extra-y := $(head-y) vmlinux.lds
/*
* 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);
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