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Merge branch 'for-next/cpuidle' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux into cpuidle/3.18 

These are the specific changes for ARM64 to make it possible to integrate the
DT based generic cpuidle driver in this tree.

It contains:
  * The documentation for the DT definitions for ARM
  * The refactoring of the cpu_suspend function for ARM64
  * Introduce the cpu_idle_init function for ARM64
  * Add the PSCI CPU SUSPEND based on the previous changes on cpu_suspend

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
This commit is contained in:
Daniel Lezcano 2014-09-25 10:47:25 +02:00
parent 0f33be009b 18910ab0d9
commit f4ea5332c8
11 changed files with 916 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
Documentation/devicetree/bindings/arm/cpus.txt
View File

@ -219,6 +219,12 @@ nodes to be present and contain the properties described below.
Value type: <phandle>
Definition: Specifies the ACC[2] node associated with this CPU.
- cpu-idle-states
Usage: Optional
Value type: <prop-encoded-array>
Definition:
# List of phandles to idle state nodes supported
by this cpu [3].
Example 1 (dual-cluster big.LITTLE system 32-bit):
@ -415,3 +421,5 @@ cpus {
--
[1] arm/msm/qcom,saw2.txt
[2] arm/msm/qcom,kpss-acc.txt
[3] ARM Linux kernel documentation - idle states bindings
Documentation/devicetree/bindings/arm/idle-states.txt

679
Documentation/devicetree/bindings/arm/idle-states.txt Normal file
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@ -0,0 +1,679 @@
==========================================
ARM idle states binding description
==========================================
==========================================
1 - Introduction
==========================================
ARM systems contain HW capable of managing power consumption dynamically,
where cores can be put in different low-power states (ranging from simple
wfi to power gating) according to OS PM policies. The CPU states representing
the range of dynamic idle states that a processor can enter at run-time, can be
specified through device tree bindings representing the parameters required
to enter/exit specific idle states on a given processor.
According to the Server Base System Architecture document (SBSA, [3]), the
power states an ARM CPU can be put into are identified by the following list:
- Running
- Idle_standby
- Idle_retention
- Sleep
- Off
The power states described in the SBSA document define the basic CPU states on
top of which ARM platforms implement power management schemes that allow an OS
PM implementation to put the processor in different idle states (which include
states listed above; "off" state is not an idle state since it does not have
wake-up capabilities, hence it is not considered in this document).
Idle state parameters (eg entry latency) are platform specific and need to be
characterized with bindings that provide the required information to OS PM
code so that it can build the required tables and use them at runtime.
The device tree binding definition for ARM idle states is the subject of this
document.
===========================================
2 - idle-states definitions
===========================================
Idle states are characterized for a specific system through a set of
timing and energy related properties, that underline the HW behaviour
triggered upon idle states entry and exit.
The following diagram depicts the CPU execution phases and related timing
properties required to enter and exit an idle state:
..__[EXEC]__|__[PREP]__|__[ENTRY]__|__[IDLE]__|__[EXIT]__|__[EXEC]__..
| | | | |
|<------ entry ------->|
| latency |
|<- exit ->|
| latency |
|<-------- min-residency -------->|
|<------- wakeup-latency ------->|
Diagram 1: CPU idle state execution phases
EXEC: Normal CPU execution.
PREP: Preparation phase before committing the hardware to idle mode
like cache flushing. This is abortable on pending wake-up
event conditions. The abort latency is assumed to be negligible
(i.e. less than the ENTRY + EXIT duration). If aborted, CPU
goes back to EXEC. This phase is optional. If not abortable,
this should be included in the ENTRY phase instead.
ENTRY: The hardware is committed to idle mode. This period must run
to completion up to IDLE before anything else can happen.
IDLE: This is the actual energy-saving idle period. This may last
between 0 and infinite time, until a wake-up event occurs.
EXIT: Period during which the CPU is brought back to operational
mode (EXEC).
entry-latency: Worst case latency required to enter the idle state. The
exit-latency may be guaranteed only after entry-latency has passed.
min-residency: Minimum period, including preparation and entry, for a given
idle state to be worthwhile energywise.
wakeup-latency: Maximum delay between the signaling of a wake-up event and the
CPU being able to execute normal code again. If not specified, this is assumed
to be entry-latency + exit-latency.
These timing parameters can be used by an OS in different circumstances.
An idle CPU requires the expected min-residency time to select the most
appropriate idle state based on the expected expiry time of the next IRQ
(ie wake-up) that causes the CPU to return to the EXEC phase.
An operating system scheduler may need to compute the shortest wake-up delay
for CPUs in the system by detecting how long will it take to get a CPU out
of an idle state, eg:
wakeup-delay = exit-latency + max(entry-latency - (now - entry-timestamp), 0)
In other words, the scheduler can make its scheduling decision by selecting
(eg waking-up) the CPU with the shortest wake-up latency.
The wake-up latency must take into account the entry latency if that period
has not expired. The abortable nature of the PREP period can be ignored
if it cannot be relied upon (e.g. the PREP deadline may occur much sooner than
the worst case since it depends on the CPU operating conditions, ie caches
state).
An OS has to reliably probe the wakeup-latency since some devices can enforce
latency constraints guarantees to work properly, so the OS has to detect the
worst case wake-up latency it can incur if a CPU is allowed to enter an
idle state, and possibly to prevent that to guarantee reliable device
functioning.
The min-residency time parameter deserves further explanation since it is
expressed in time units but must factor in energy consumption coefficients.
The energy consumption of a cpu when it enters a power state can be roughly
characterised by the following graph:
|
|
|
e |
n | /---
e | /------
r | /------
g | /-----
y | /------
| ----
| /|
| / |
| / |
| / |
| / |
| / |
|/ |
-----|-------+----------------------------------
0| 1 time(ms)
Graph 1: Energy vs time example
The graph is split in two parts delimited by time 1ms on the X-axis.
The graph curve with X-axis values = { x | 0 < x < 1ms } has a steep slope
and denotes the energy costs incurred whilst entering and leaving the idle
state.
The graph curve in the area delimited by X-axis values = {x | x > 1ms } has
shallower slope and essentially represents the energy consumption of the idle
state.
min-residency is defined for a given idle state as the minimum expected
residency time for a state (inclusive of preparation and entry) after
which choosing that state become the most energy efficient option. A good
way to visualise this, is by taking the same graph above and comparing some
states energy consumptions plots.
For sake of simplicity, let's consider a system with two idle states IDLE1,
and IDLE2:
|
|
|
| /-- IDLE1
e | /---
n | /----
e | /---
r | /-----/--------- IDLE2
g | /-------/---------
y | ------------ /---|
| / /---- |
| / /--- |
| / /---- |
| / /--- |
| --- |
| / |
| / |
|/ | time
---/----------------------------+------------------------
|IDLE1-energy < IDLE2-energy | IDLE2-energy < IDLE1-energy
|
IDLE2-min-residency
Graph 2: idle states min-residency example
In graph 2 above, that takes into account idle states entry/exit energy
costs, it is clear that if the idle state residency time (ie time till next
wake-up IRQ) is less than IDLE2-min-residency, IDLE1 is the better idle state
choice energywise.
This is mainly down to the fact that IDLE1 entry/exit energy costs are lower
than IDLE2.
However, the lower power consumption (ie shallower energy curve slope) of idle
state IDLE2 implies that after a suitable time, IDLE2 becomes more energy
efficient.
The time at which IDLE2 becomes more energy efficient than IDLE1 (and other
shallower states in a system with multiple idle states) is defined
IDLE2-min-residency and corresponds to the time when energy consumption of
IDLE1 and IDLE2 states breaks even.
The definitions provided in this section underpin the idle states
properties specification that is the subject of the following sections.
===========================================
3 - idle-states node
===========================================
ARM processor idle states are defined within the idle-states node, which is
a direct child of the cpus node [1] and provides a container where the
processor idle states, defined as device tree nodes, are listed.
- idle-states node
Usage: Optional - On ARM systems, it is a container of processor idle
states nodes. If the system does not provide CPU
power management capabilities or the processor just
supports idle_standby an idle-states node is not
required.
Description: idle-states node is a container node, where its
subnodes describe the CPU idle states.
Node name must be "idle-states".
The idle-states node's parent node must be the cpus node.
The idle-states node's child nodes can be:
- one or more state nodes
Any other configuration is considered invalid.
An idle-states node defines the following properties:
- entry-method
Value type: <stringlist>
Usage and definition depend on ARM architecture version.
# On ARM v8 64-bit this property is required and must
be one of:
- "psci" (see bindings in [2])
# On ARM 32-bit systems this property is optional
The nodes describing the idle states (state) can only be defined within the
idle-states node, any other configuration is considered invalid and therefore
must be ignored.
===========================================
4 - state node
===========================================
A state node represents an idle state description and must be defined as
follows:
- state node
Description: must be child of the idle-states node
The state node name shall follow standard device tree naming
rules ([5], 2.2.1 "Node names"), in particular state nodes which
are siblings within a single common parent must be given a unique name.
The idle state entered by executing the wfi instruction (idle_standby
SBSA,[3][4]) is considered standard on all ARM platforms and therefore
must not be listed.
With the definitions provided above, the following list represents
the valid properties for a state node:
- compatible
Usage: Required
Value type: <stringlist>
Definition: Must be "arm,idle-state".
- local-timer-stop
Usage: See definition
Value type: <none>
Definition: if present the CPU local timer control logic is
lost on state entry, otherwise it is retained.
- entry-latency-us
Usage: Required
Value type: <prop-encoded-array>
Definition: u32 value representing worst case latency in
microseconds required to enter the idle state.
The exit-latency-us duration may be guaranteed
only after entry-latency-us has passed.
- exit-latency-us
Usage: Required
Value type: <prop-encoded-array>
Definition: u32 value representing worst case latency
in microseconds required to exit the idle state.
- min-residency-us
Usage: Required
Value type: <prop-encoded-array>
Definition: u32 value representing minimum residency duration
in microseconds, inclusive of preparation and
entry, for this idle state to be considered
worthwhile energy wise (refer to section 2 of
this document for a complete description).
- wakeup-latency-us:
Usage: Optional
Value type: <prop-encoded-array>
Definition: u32 value representing maximum delay between the
signaling of a wake-up event and the CPU being
able to execute normal code again. If omitted,
this is assumed to be equal to:
entry-latency-us + exit-latency-us
It is important to supply this value on systems
where the duration of PREP phase (see diagram 1,
section 2) is non-neglibigle.
In such systems entry-latency-us + exit-latency-us
will exceed wakeup-latency-us by this duration.
In addition to the properties listed above, a state node may require
additional properties specifics to the entry-method defined in the
idle-states node, please refer to the entry-method bindings
documentation for properties definitions.
===========================================
4 - Examples
===========================================
Example 1 (ARM 64-bit, 16-cpu system, PSCI enable-method):
cpus {
#size-cells = <0>;
#address-cells = <2>;
CPU0: cpu@0 {
device_type = "cpu";
compatible = "arm,cortex-a57";
reg = <0x0 0x0>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
};
CPU1: cpu@1 {
device_type = "cpu";
compatible = "arm,cortex-a57";
reg = <0x0 0x1>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
};
CPU2: cpu@100 {
device_type = "cpu";
compatible = "arm,cortex-a57";
reg = <0x0 0x100>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
};
CPU3: cpu@101 {
device_type = "cpu";
compatible = "arm,cortex-a57";
reg = <0x0 0x101>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
};
CPU4: cpu@10000 {
device_type = "cpu";
compatible = "arm,cortex-a57";
reg = <0x0 0x10000>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
};
CPU5: cpu@10001 {
device_type = "cpu";
compatible = "arm,cortex-a57";
reg = <0x0 0x10001>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
};
CPU6: cpu@10100 {
device_type = "cpu";
compatible = "arm,cortex-a57";
reg = <0x0 0x10100>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
};
CPU7: cpu@10101 {
device_type = "cpu";
compatible = "arm,cortex-a57";
reg = <0x0 0x10101>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
};
CPU8: cpu@100000000 {
device_type = "cpu";
compatible = "arm,cortex-a53";
reg = <0x1 0x0>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
};
CPU9: cpu@100000001 {
device_type = "cpu";
compatible = "arm,cortex-a53";
reg = <0x1 0x1>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
};
CPU10: cpu@100000100 {
device_type = "cpu";
compatible = "arm,cortex-a53";
reg = <0x1 0x100>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
};
CPU11: cpu@100000101 {
device_type = "cpu";
compatible = "arm,cortex-a53";
reg = <0x1 0x101>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
};
CPU12: cpu@100010000 {
device_type = "cpu";
compatible = "arm,cortex-a53";
reg = <0x1 0x10000>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
};
CPU13: cpu@100010001 {
device_type = "cpu";
compatible = "arm,cortex-a53";
reg = <0x1 0x10001>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
};
CPU14: cpu@100010100 {
device_type = "cpu";
compatible = "arm,cortex-a53";
reg = <0x1 0x10100>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
};
CPU15: cpu@100010101 {
device_type = "cpu";
compatible = "arm,cortex-a53";
reg = <0x1 0x10101>;
enable-method = "psci";
cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
};
idle-states {
entry-method = "arm,psci";
CPU_RETENTION_0_0: cpu-retention-0-0 {
compatible = "arm,idle-state";
arm,psci-suspend-param = <0x0010000>;
entry-latency-us = <20>;
exit-latency-us = <40>;
min-residency-us = <80>;
};
CLUSTER_RETENTION_0: cluster-retention-0 {
compatible = "arm,idle-state";
local-timer-stop;
arm,psci-suspend-param = <0x1010000>;
entry-latency-us = <50>;
exit-latency-us = <100>;
min-residency-us = <250>;
wakeup-latency-us = <130>;
};
CPU_SLEEP_0_0: cpu-sleep-0-0 {
compatible = "arm,idle-state";
local-timer-stop;
arm,psci-suspend-param = <0x0010000>;
entry-latency-us = <250>;
exit-latency-us = <500>;
min-residency-us = <950>;
};
CLUSTER_SLEEP_0: cluster-sleep-0 {
compatible = "arm,idle-state";
local-timer-stop;
arm,psci-suspend-param = <0x1010000>;
entry-latency-us = <600>;
exit-latency-us = <1100>;
min-residency-us = <2700>;
wakeup-latency-us = <1500>;
};
CPU_RETENTION_1_0: cpu-retention-1-0 {
compatible = "arm,idle-state";
arm,psci-suspend-param = <0x0010000>;
entry-latency-us = <20>;
exit-latency-us = <40>;
min-residency-us = <90>;
};
CLUSTER_RETENTION_1: cluster-retention-1 {
compatible = "arm,idle-state";
local-timer-stop;
arm,psci-suspend-param = <0x1010000>;
entry-latency-us = <50>;
exit-latency-us = <100>;
min-residency-us = <270>;
wakeup-latency-us = <100>;
};
CPU_SLEEP_1_0: cpu-sleep-1-0 {
compatible = "arm,idle-state";
local-timer-stop;
arm,psci-suspend-param = <0x0010000>;
entry-latency-us = <70>;
exit-latency-us = <100>;
min-residency-us = <300>;
wakeup-latency-us = <150>;
};
CLUSTER_SLEEP_1: cluster-sleep-1 {
compatible = "arm,idle-state";
local-timer-stop;
arm,psci-suspend-param = <0x1010000>;
entry-latency-us = <500>;
exit-latency-us = <1200>;
min-residency-us = <3500>;
wakeup-latency-us = <1300>;
};
};
};
Example 2 (ARM 32-bit, 8-cpu system, two clusters):
cpus {
#size-cells = <0>;
#address-cells = <1>;
CPU0: cpu@0 {
device_type = "cpu";
compatible = "arm,cortex-a15";
reg = <0x0>;
cpu-idle-states = <&CPU_SLEEP_0_0 &CLUSTER_SLEEP_0>;
};
CPU1: cpu@1 {
device_type = "cpu";
compatible = "arm,cortex-a15";
reg = <0x1>;
cpu-idle-states = <&CPU_SLEEP_0_0 &CLUSTER_SLEEP_0>;
};
CPU2: cpu@2 {
device_type = "cpu";
compatible = "arm,cortex-a15";
reg = <0x2>;
cpu-idle-states = <&CPU_SLEEP_0_0 &CLUSTER_SLEEP_0>;
};
CPU3: cpu@3 {
device_type = "cpu";
compatible = "arm,cortex-a15";
reg = <0x3>;
cpu-idle-states = <&CPU_SLEEP_0_0 &CLUSTER_SLEEP_0>;
};
CPU4: cpu@100 {
device_type = "cpu";
compatible = "arm,cortex-a7";
reg = <0x100>;
cpu-idle-states = <&CPU_SLEEP_1_0 &CLUSTER_SLEEP_1>;
};
CPU5: cpu@101 {
device_type = "cpu";
compatible = "arm,cortex-a7";
reg = <0x101>;
cpu-idle-states = <&CPU_SLEEP_1_0 &CLUSTER_SLEEP_1>;
};
CPU6: cpu@102 {
device_type = "cpu";
compatible = "arm,cortex-a7";
reg = <0x102>;
cpu-idle-states = <&CPU_SLEEP_1_0 &CLUSTER_SLEEP_1>;
};
CPU7: cpu@103 {
device_type = "cpu";
compatible = "arm,cortex-a7";
reg = <0x103>;
cpu-idle-states = <&CPU_SLEEP_1_0 &CLUSTER_SLEEP_1>;
};
idle-states {
CPU_SLEEP_0_0: cpu-sleep-0-0 {
compatible = "arm,idle-state";
local-timer-stop;
entry-latency-us = <200>;
exit-latency-us = <100>;
min-residency-us = <400>;
wakeup-latency-us = <250>;
};
CLUSTER_SLEEP_0: cluster-sleep-0 {
compatible = "arm,idle-state";
local-timer-stop;
entry-latency-us = <500>;
exit-latency-us = <1500>;
min-residency-us = <2500>;
wakeup-latency-us = <1700>;
};
CPU_SLEEP_1_0: cpu-sleep-1-0 {
compatible = "arm,idle-state";
local-timer-stop;
entry-latency-us = <300>;
exit-latency-us = <500>;
min-residency-us = <900>;
wakeup-latency-us = <600>;
};
CLUSTER_SLEEP_1: cluster-sleep-1 {
compatible = "arm,idle-state";
local-timer-stop;
entry-latency-us = <800>;
exit-latency-us = <2000>;
min-residency-us = <6500>;
wakeup-latency-us = <2300>;
};
};
};
===========================================
5 - References
===========================================
[1] ARM Linux Kernel documentation - CPUs bindings
Documentation/devicetree/bindings/arm/cpus.txt
[2] ARM Linux Kernel documentation - PSCI bindings
Documentation/devicetree/bindings/arm/psci.txt
[3] ARM Server Base System Architecture (SBSA)
http://infocenter.arm.com/help/index.jsp
[4] ARM Architecture Reference Manuals
http://infocenter.arm.com/help/index.jsp
[5] ePAPR standard
https://www.power.org/documentation/epapr-version-1-1/

14
Documentation/devicetree/bindings/arm/psci.txt
View File

@ -50,6 +50,16 @@ Main node optional properties:
- migrate : Function ID for MIGRATE operation
Device tree nodes that require usage of PSCI CPU_SUSPEND function (ie idle
state nodes, as per bindings in [1]) must specify the following properties:
- arm,psci-suspend-param
Usage: Required for state nodes[1] if the corresponding
idle-states node entry-method property is set
to "psci".
Value type: <u32>
Definition: power_state parameter to pass to the PSCI
suspend call.
Example:
@ -64,7 +74,6 @@ Case 1: PSCI v0.1 only.
migrate = <0x95c10003>;
};
Case 2: PSCI v0.2 only
psci {
@ -88,3 +97,6 @@ Case 3: PSCI v0.2 and PSCI v0.1.
...
};
[1] Kernel documentation - ARM idle states bindings
Documentation/devicetree/bindings/arm/idle-states.txt

3
arch/arm64/include/asm/cpu_ops.h
View File

@ -28,6 +28,8 @@ struct device_node;
* enable-method property.
* @cpu_init: Reads any data necessary for a specific enable-method from the
* devicetree, for a given cpu node and proposed logical id.
* @cpu_init_idle: Reads any data necessary to initialize CPU idle states from
* devicetree, for a given cpu node and proposed logical id.
* @cpu_prepare: Early one-time preparation step for a cpu. If there is a
* mechanism for doing so, tests whether it is possible to boot
* the given CPU.
@ -47,6 +49,7 @@ struct device_node;
struct cpu_operations {
const char *name;
int (*cpu_init)(struct device_node *, unsigned int);
int (*cpu_init_idle)(struct device_node *, unsigned int);
int (*cpu_prepare)(unsigned int);
int (*cpu_boot)(unsigned int);
void (*cpu_postboot)(void);

13
arch/arm64/include/asm/cpuidle.h Normal file
View File

@ -0,0 +1,13 @@
#ifndef __ASM_CPUIDLE_H
#define __ASM_CPUIDLE_H
#ifdef CONFIG_CPU_IDLE
extern int cpu_init_idle(unsigned int cpu);
#else
static inline int cpu_init_idle(unsigned int cpu)
{
return -EOPNOTSUPP;
}
#endif
#endif

1
arch/arm64/include/asm/suspend.h
View File

@ -21,6 +21,7 @@ struct sleep_save_sp {
phys_addr_t save_ptr_stash_phys;
};
extern int __cpu_suspend(unsigned long arg, int (*fn)(unsigned long));
extern void cpu_resume(void);
extern int cpu_suspend(unsigned long);

1
arch/arm64/kernel/Makefile
View File

@ -26,6 +26,7 @@ arm64-obj-$(CONFIG_PERF_EVENTS) += perf_regs.o
arm64-obj-$(CONFIG_HW_PERF_EVENTS) += perf_event.o
arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
arm64-obj-$(CONFIG_ARM64_CPU_SUSPEND) += sleep.o suspend.o
arm64-obj-$(CONFIG_CPU_IDLE) += cpuidle.o
arm64-obj-$(CONFIG_JUMP_LABEL) += jump_label.o
arm64-obj-$(CONFIG_KGDB) += kgdb.o
arm64-obj-$(CONFIG_EFI) += efi.o efi-stub.o efi-entry.o

31
arch/arm64/kernel/cpuidle.c Normal file
View File

@ -0,0 +1,31 @@
/*
* ARM64 CPU idle arch support
*
* Copyright (C) 2014 ARM Ltd.
* Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
*
* 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.
*/
#include <linux/of.h>
#include <linux/of_device.h>
#include <asm/cpuidle.h>
#include <asm/cpu_ops.h>
int cpu_init_idle(unsigned int cpu)
{
int ret = -EOPNOTSUPP;
struct device_node *cpu_node = of_cpu_device_node_get(cpu);
if (!cpu_node)
return -ENODEV;
if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_init_idle)
ret = cpu_ops[cpu]->cpu_init_idle(cpu_node, cpu);
of_node_put(cpu_node);
return ret;
}

104
arch/arm64/kernel/psci.c
View File

@ -21,6 +21,7 @@
#include <linux/reboot.h>
#include <linux/pm.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <uapi/linux/psci.h>
#include <asm/compiler.h>
@ -28,6 +29,7 @@
#include <asm/errno.h>
#include <asm/psci.h>
#include <asm/smp_plat.h>
#include <asm/suspend.h>
#include <asm/system_misc.h>
#define PSCI_POWER_STATE_TYPE_STANDBY 0
@ -65,6 +67,8 @@ enum psci_function {
PSCI_FN_MAX,
};
static DEFINE_PER_CPU_READ_MOSTLY(struct psci_power_state *, psci_power_state);
static u32 psci_function_id[PSCI_FN_MAX];
static int psci_to_linux_errno(int errno)
@ -93,6 +97,18 @@ static u32 psci_power_state_pack(struct psci_power_state state)
& PSCI_0_2_POWER_STATE_AFFL_MASK);
}
static void psci_power_state_unpack(u32 power_state,
struct psci_power_state *state)
{
state->id = (power_state & PSCI_0_2_POWER_STATE_ID_MASK) >>
PSCI_0_2_POWER_STATE_ID_SHIFT;
state->type = (power_state & PSCI_0_2_POWER_STATE_TYPE_MASK) >>
PSCI_0_2_POWER_STATE_TYPE_SHIFT;
state->affinity_level =
(power_state & PSCI_0_2_POWER_STATE_AFFL_MASK) >>
PSCI_0_2_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.
@ -199,6 +215,63 @@ static int psci_migrate_info_type(void)
return err;
}
static int __maybe_unused cpu_psci_cpu_init_idle(struct device_node *cpu_node,
unsigned int cpu)
{
int i, ret, count = 0;
struct psci_power_state *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 psci_power_state;
state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
ret = of_property_read_u32(state_node,
"arm,psci-suspend-param",
&psci_power_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_debug("psci-power-state %#x index %d\n", psci_power_state,
i);
psci_power_state_unpack(psci_power_state, &psci_states[i]);
}
/* 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 get_set_conduit_method(struct device_node *np)
{
const char *method;
@ -436,8 +509,39 @@ static int cpu_psci_cpu_kill(unsigned int cpu)
#endif
#endif
static int psci_suspend_finisher(unsigned long index)
{
struct psci_power_state *state = __get_cpu_var(psci_power_state);
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 = __get_cpu_var(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->type == PSCI_POWER_STATE_TYPE_STANDBY)
ret = psci_ops.cpu_suspend(state[index - 1], 0);
else
ret = __cpu_suspend(index, psci_suspend_finisher);
return ret;
}
const struct cpu_operations cpu_psci_ops = {
.name = "psci",
#ifdef CONFIG_CPU_IDLE
.cpu_init_idle = cpu_psci_cpu_init_idle,
.cpu_suspend = cpu_psci_cpu_suspend,
#endif
#ifdef CONFIG_SMP
.cpu_init = cpu_psci_cpu_init,
.cpu_prepare = cpu_psci_cpu_prepare,

47
arch/arm64/kernel/sleep.S
View File

@ -49,28 +49,39 @@
orr \dst, \dst, \mask // dst|=(aff3>>rs3)
.endm
/*
* Save CPU state for a suspend. This saves callee registers, and allocates
* space on the kernel stack to save the CPU specific registers + some
* other data for resume.
* Save CPU state for a suspend and execute the suspend finisher.
* On success it will return 0 through cpu_resume - ie through a CPU
* soft/hard reboot from the reset vector.
* On failure it returns the suspend finisher return value or force
* -EOPNOTSUPP if the finisher erroneously returns 0 (the suspend finisher
* is not allowed to return, if it does this must be considered failure).
* It saves callee registers, and allocates space on the kernel stack
* to save the CPU specific registers + some other data for resume.
*
* x0 = suspend finisher argument
* x1 = suspend finisher function pointer
*/
ENTRY(__cpu_suspend)
ENTRY(__cpu_suspend_enter)
stp x29, lr, [sp, #-96]!
stp x19, x20, [sp,#16]
stp x21, x22, [sp,#32]
stp x23, x24, [sp,#48]
stp x25, x26, [sp,#64]
stp x27, x28, [sp,#80]
/*
* Stash suspend finisher and its argument in x20 and x19
*/
mov x19, x0
mov x20, x1
mov x2, sp
sub sp, sp, #CPU_SUSPEND_SZ // allocate cpu_suspend_ctx
mov x1, sp
mov x0, sp
/*
* x1 now points to struct cpu_suspend_ctx allocated on the stack
* x0 now points to struct cpu_suspend_ctx allocated on the stack
*/
str x2, [x1, #CPU_CTX_SP]
ldr x2, =sleep_save_sp
ldr x2, [x2, #SLEEP_SAVE_SP_VIRT]
str x2, [x0, #CPU_CTX_SP]
ldr x1, =sleep_save_sp
ldr x1, [x1, #SLEEP_SAVE_SP_VIRT]
#ifdef CONFIG_SMP
mrs x7, mpidr_el1
ldr x9, =mpidr_hash
@ -82,11 +93,21 @@ ENTRY(__cpu_suspend)
ldp w3, w4, [x9, #MPIDR_HASH_SHIFTS]
ldp w5, w6, [x9, #(MPIDR_HASH_SHIFTS + 8)]
compute_mpidr_hash x8, x3, x4, x5, x6, x7, x10
add x2, x2, x8, lsl #3
add x1, x1, x8, lsl #3
#endif
bl __cpu_suspend_finisher
bl __cpu_suspend_save
/*
* Grab suspend finisher in x20 and its argument in x19
*/
mov x0, x19
mov x1, x20
/*
* We are ready for power down, fire off the suspend finisher
* in x1, with argument in x0
*/
blr x1
/*
* Never gets here, unless suspend fails.
* Never gets here, unless suspend finisher fails.
* Successful cpu_suspend should return from cpu_resume, returning
* through this code path is considered an error
* If the return value is set to 0 force x0 = -EOPNOTSUPP
@ -103,7 +124,7 @@ ENTRY(__cpu_suspend)
ldp x27, x28, [sp, #80]
ldp x29, lr, [sp], #96
ret
ENDPROC(__cpu_suspend)
ENDPROC(__cpu_suspend_enter)
.ltorg
/*

48
arch/arm64/kernel/suspend.c
View File

@ -9,22 +9,19 @@
#include <asm/suspend.h>
#include <asm/tlbflush.h>
extern int __cpu_suspend(unsigned long);
extern int __cpu_suspend_enter(unsigned long arg, int (*fn)(unsigned long));
/*
* This is called by __cpu_suspend() to save the state, and do whatever
* This is called by __cpu_suspend_enter() to save the state, and do whatever
* flushing is required to ensure that when the CPU goes to sleep we have
* the necessary data available when the caches are not searched.
*
* @arg: Argument to pass to suspend operations
* @ptr: CPU context virtual address
* @save_ptr: address of the location where the context physical address
* must be saved
* ptr: CPU context virtual address
* save_ptr: address of the location where the context physical address
* must be saved
*/
int __cpu_suspend_finisher(unsigned long arg, struct cpu_suspend_ctx *ptr,
phys_addr_t *save_ptr)
void notrace __cpu_suspend_save(struct cpu_suspend_ctx *ptr,
phys_addr_t *save_ptr)
{
int cpu = smp_processor_id();
*save_ptr = virt_to_phys(ptr);
cpu_do_suspend(ptr);
@ -35,8 +32,6 @@ int __cpu_suspend_finisher(unsigned long arg, struct cpu_suspend_ctx *ptr,
*/
__flush_dcache_area(ptr, sizeof(*ptr));
__flush_dcache_area(save_ptr, sizeof(*save_ptr));
return cpu_ops[cpu]->cpu_suspend(arg);
}
/*
@ -56,15 +51,15 @@ void __init cpu_suspend_set_dbg_restorer(void (*hw_bp_restore)(void *))
}
/**
* cpu_suspend
* cpu_suspend() - function to enter a low-power state
* @arg: argument to pass to CPU suspend operations
*
* @arg: argument to pass to the finisher function
* Return: 0 on success, -EOPNOTSUPP if CPU suspend hook not initialized, CPU
* operations back-end error code otherwise.
*/
int cpu_suspend(unsigned long arg)
{
struct mm_struct *mm = current->active_mm;
int ret, cpu = smp_processor_id();
unsigned long flags;
int cpu = smp_processor_id();
/*
* If cpu_ops have not been registered or suspend
@ -72,6 +67,21 @@ int cpu_suspend(unsigned long arg)
*/
if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_suspend)
return -EOPNOTSUPP;
return cpu_ops[cpu]->cpu_suspend(arg);
}
/*
* __cpu_suspend
*
* arg: argument to pass to the finisher function
* fn: finisher function pointer
*
*/
int __cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
{
struct mm_struct *mm = current->active_mm;
int ret;
unsigned long flags;
/*
* From this point debug exceptions are disabled to prevent
@ -86,7 +96,7 @@ int cpu_suspend(unsigned long arg)
* page tables, so that the thread address space is properly
* set-up on function return.
*/
ret = __cpu_suspend(arg);
ret = __cpu_suspend_enter(arg, fn);
if (ret == 0) {
cpu_switch_mm(mm->pgd, mm);
flush_tlb_all();
@ -95,7 +105,7 @@ int cpu_suspend(unsigned long arg)
* Restore per-cpu offset before any kernel
* subsystem relying on it has a chance to run.
*/
set_my_cpu_offset(per_cpu_offset(cpu));
set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
/*
* Restore HW breakpoint registers to sane values