* [PATCH v2 2/4] dt-bindings: thermal: Add the idle cooling device
2020-04-14 16:26 [PATCH v2 1/4] powercap/drivers/idle_inject: Specify idle state max latency Daniel Lezcano
@ 2020-04-14 16:26 ` Daniel Lezcano
2020-04-14 21:45 ` Rob Herring
2020-04-14 16:26 ` [PATCH v2 3/4] thermal/drivers/cpuidle_cooling: Change the registration function Daniel Lezcano
2020-04-14 16:26 ` [PATCH v2 4/4] thermal: cpuidle: Register cpuidle cooling device Daniel Lezcano
2 siblings, 1 reply; 6+ messages in thread
From: Daniel Lezcano @ 2020-04-14 16:26 UTC (permalink / raw)
To: daniel.lezcano, rui.zhang
Cc: amit.kucheria, Rob Herring, Mark Rutland, open list:THERMAL,
open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS,
open list
Some devices are not able to cool down by reducing their voltage /
frequency because it could be not available or the system does not
allow voltage scaling. In this configuration, it is not possible to
use this strategy and the idle injection cooling device can be used
instead.
One idle cooling device is now present for the CPU as implemented by
the combination of the idle injection framework belonging to the power
capping framework and the thermal cooling device. The missing part is
the DT binding providing a way to describe how the cooling device will
work on the system.
A first iteration was done by making the cooling device to point to
the idle state. Unfortunately it does not make sense because it would
need to duplicate the idle state description for each CPU in order to
have a different phandle and make the thermal internal framework
happy.
It was proposed to add an cooling-cells to <3>, unfortunately the
thermal framework is expecting a value of <2> as stated by the
documentation and it is not possible from the cooling device generic
code to loop this third value to the back end cooling device.
Another proposal was to add a child 'thermal-idle' node as the SCMI
does. This approach allows to have a self-contained configuration for
the idle cooling device without colliding with the cpufreq cooling
device which is based on the CPU node. In addition, it allows to have
the cpufreq cooling device and the idle cooling device to co-exist
together as shown in the example.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
- V2:
- Fixed comment type
- Added dual license
- Fixed description s/begins to/should/
- Changed name s/duration/duration-us/
- Changed name s/latency/exit-latency-us/
- Removed types for latency / duration
- Fixed s/idle-thermal/thermal-idle/
---
.../bindings/thermal/thermal-idle.yaml | 146 ++++++++++++++++++
1 file changed, 146 insertions(+)
create mode 100644 Documentation/devicetree/bindings/thermal/thermal-idle.yaml
diff --git a/Documentation/devicetree/bindings/thermal/thermal-idle.yaml b/Documentation/devicetree/bindings/thermal/thermal-idle.yaml
new file mode 100644
index 000000000000..760308fcd2fb
--- /dev/null
+++ b/Documentation/devicetree/bindings/thermal/thermal-idle.yaml
@@ -0,0 +1,146 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright 2020 Linaro Ltd.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/thermal/thermal-idle.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Thermal idle cooling device binding
+
+maintainers:
+ - Daniel Lezcano <daniel.lezcano@linaro.org>
+
+description: |
+ The thermal idle cooling device allows the system to passively
+ mitigate the temperature on the device by injecting idle cycles,
+ forcing it to cool down.
+
+ This binding describes the thermal idle node.
+
+properties:
+ $nodename:
+ const: thermal-idle
+ description: |
+ A thermal-idle node describes the idle cooling device properties to
+ cool down efficiently the attached thermal zone.
+
+ '#cooling-cells':
+ const: 2
+ description: |
+ Must be 2, in order to specify minimum and maximum cooling state used in
+ the cooling-maps reference. The first cell is the minimum cooling state
+ and the second cell is the maximum cooling state requested.
+
+ duration-us:
+ description: |
+ The idle duration in microsecond the device should cool down.
+
+ exit-latency-us:
+ description: |
+ The exit latency constraint in microsecond for the injected
+ idle state for the device. It is the latency constraint to
+ apply when selecting an idle state from among all the present
+ ones.
+
+
+required:
+ - '#cooling-cells'
+
+examples:
+ - |
+ #include <dt-bindings/thermal/thermal.h>
+
+ // Example: Combining idle cooling device on big CPUs with cpufreq cooling device
+ cpus {
+ #address-cells = <2>;
+ #size-cells = <0>;
+
+ /* ... */
+
+ cpu_b0: cpu@100 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x100>;
+ enable-method = "psci";
+ capacity-dmips-mhz = <1024>;
+ dynamic-power-coefficient = <436>;
+ #cooling-cells = <2>; /* min followed by max */
+ cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
+ thermal-idle {
+ #cooling-cells = <2>;
+ duration-us = <10000>;
+ exit-latency-us = <500>;
+ };
+ };
+
+ cpu_b1: cpu@101 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x101>;
+ enable-method = "psci";
+ capacity-dmips-mhz = <1024>;
+ dynamic-power-coefficient = <436>;
+ #cooling-cells = <2>; /* min followed by max */
+ cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
+ thermal-idle {
+ #cooling-cells = <2>;
+ duration-us = <10000>;
+ exit-latency-us = <500>;
+ };
+ };
+
+ /* ... */
+
+ };
+
+ /* ... */
+
+ thermal_zones {
+ cpu_thermal: cpu {
+ polling-delay-passive = <100>;
+ polling-delay = <1000>;
+
+ /* ... */
+
+ trips {
+ cpu_alert0: cpu_alert0 {
+ temperature = <65000>;
+ hysteresis = <2000>;
+ type = "passive";
+ };
+
+ cpu_alert1: cpu_alert1 {
+ temperature = <70000>;
+ hysteresis = <2000>;
+ type = "passive";
+ };
+
+ cpu_alert2: cpu_alert2 {
+ temperature = <75000>;
+ hysteresis = <2000>;
+ type = "passive";
+ };
+
+ cpu_crit: cpu_crit {
+ temperature = <95000>;
+ hysteresis = <2000>;
+ type = "critical";
+ };
+ };
+
+ cooling-maps {
+ map0 {
+ trip = <&cpu_alert1>;
+ cooling-device = <&{/cpus/cpu@100/thermal-idle} 0 15 >,
+ <&{/cpus/cpu@101/thermal-idle} 0 15>;
+ };
+
+ map1 {
+ trip = <&cpu_alert2>;
+ cooling-device =
+ <&cpu_b0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
+ <&cpu_b1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
+ };
+ };
+ };
+ };
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 3/4] thermal/drivers/cpuidle_cooling: Change the registration function
2020-04-14 16:26 [PATCH v2 1/4] powercap/drivers/idle_inject: Specify idle state max latency Daniel Lezcano
2020-04-14 16:26 ` [PATCH v2 2/4] dt-bindings: thermal: Add the idle cooling device Daniel Lezcano
@ 2020-04-14 16:26 ` Daniel Lezcano
2020-04-14 16:26 ` [PATCH v2 4/4] thermal: cpuidle: Register cpuidle cooling device Daniel Lezcano
2 siblings, 0 replies; 6+ messages in thread
From: Daniel Lezcano @ 2020-04-14 16:26 UTC (permalink / raw)
To: daniel.lezcano, rui.zhang
Cc: amit.kucheria, Viresh Kumar, Amit Daniel Kachhap, Javi Merino,
open list:THERMAL/CPU_COOLING, open list
Today, there is no user for the cpuidle cooling device. The targetted
platform is ARM and ARM64.
The cpuidle and the cpufreq cooling device are based on the device tree.
As the cpuidle cooling device can have its own configuration depending
on the platform and the available idle states. The DT node description
will give the optional properties to set the cooling device up.
Do no longer rely on the CPU node which is prone to error and will
lead to a confusion in the DT because the cpufreq cooling device is
also using it. Let initialize the cpuidle cooling device with the DT
binding.
This was tested on:
- hikey960
- hikey6220
- rock960
- db845c
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
drivers/thermal/cpuidle_cooling.c | 58 +++++++++++++++++++++++++------
include/linux/cpu_cooling.h | 7 ----
2 files changed, 47 insertions(+), 18 deletions(-)
diff --git a/drivers/thermal/cpuidle_cooling.c b/drivers/thermal/cpuidle_cooling.c
index 0bb843246f59..b2c81c427f05 100644
--- a/drivers/thermal/cpuidle_cooling.c
+++ b/drivers/thermal/cpuidle_cooling.c
@@ -10,6 +10,7 @@
#include <linux/err.h>
#include <linux/idle_inject.h>
#include <linux/idr.h>
+#include <linux/of_device.h>
#include <linux/slab.h>
#include <linux/thermal.h>
@@ -154,22 +155,25 @@ static struct thermal_cooling_device_ops cpuidle_cooling_ops = {
};
/**
- * cpuidle_of_cooling_register - Idle cooling device initialization function
+ * __cpuidle_cooling_register: register the cooling device
* @drv: a cpuidle driver structure pointer
- * @np: a node pointer to a device tree cooling device node
+ * @np: a device node structure pointer used for the thermal binding
*
- * This function is in charge of creating a cooling device per cpuidle
- * driver and register it to thermal framework.
+ * This function is in charge of allocating the cpuidle cooling device
+ * structure, the idle injection, initialize them and register the
+ * cooling device to the thermal framework.
*
- * Return: zero on success, or negative value corresponding to the
- * error detected in the underlying subsystems.
+ * Return: zero on success, a negative value returned by one of the
+ * underlying subsystem in case of error
*/
-int cpuidle_of_cooling_register(struct device_node *np,
- struct cpuidle_driver *drv)
+static int __cpuidle_cooling_register(struct device_node *np,
+ struct cpuidle_driver *drv)
{
struct idle_inject_device *ii_dev;
struct cpuidle_cooling_device *idle_cdev;
struct thermal_cooling_device *cdev;
+ unsigned int idle_duration_us = TICK_USEC;
+ unsigned int latency_us = UINT_MAX;
char dev_name[THERMAL_NAME_LENGTH];
int id, ret;
@@ -191,7 +195,11 @@ int cpuidle_of_cooling_register(struct device_node *np,
goto out_id;
}
- idle_inject_set_duration(ii_dev, TICK_USEC, TICK_USEC);
+ of_property_read_u32(np, "duration", &idle_duration_us);
+ of_property_read_u32(np, "latency", &latency_us);
+
+ idle_inject_set_duration(ii_dev, TICK_USEC, idle_duration_us);
+ idle_inject_set_latency(ii_dev, latency_us);
idle_cdev->ii_dev = ii_dev;
@@ -204,6 +212,9 @@ int cpuidle_of_cooling_register(struct device_node *np,
goto out_unregister;
}
+ pr_info("%s: Idle injection set with idle duration=%u, latency=%u\n",
+ dev_name, idle_duration_us, latency_us);
+
return 0;
out_unregister:
@@ -221,12 +232,37 @@ int cpuidle_of_cooling_register(struct device_node *np,
* @drv: a cpuidle driver structure pointer
*
* This function is in charge of creating a cooling device per cpuidle
- * driver and register it to thermal framework.
+ * driver and register it to the thermal framework.
*
* Return: zero on success, or negative value corresponding to the
* error detected in the underlying subsystems.
*/
int cpuidle_cooling_register(struct cpuidle_driver *drv)
{
- return cpuidle_of_cooling_register(NULL, drv);
+ struct device_node *cooling_node;
+ struct device_node *cpu_node;
+ int cpu, ret;
+
+ for_each_cpu(cpu, drv->cpumask) {
+
+ cpu_node = of_cpu_device_node_get(cpu);
+
+ cooling_node = of_get_child_by_name(cpu_node, "idle-thermal");
+
+ of_node_put(cpu_node);
+
+ if (!cooling_node)
+ continue;
+
+ ret = __cpuidle_cooling_register(cooling_node, drv);
+
+ of_node_put(cooling_node);
+
+ if (ret)
+ return ret;
+
+ cooling_node = NULL;
+ }
+
+ return 0;
}
diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h
index 65501d8f9778..4d7b4a303327 100644
--- a/include/linux/cpu_cooling.h
+++ b/include/linux/cpu_cooling.h
@@ -64,18 +64,11 @@ struct cpuidle_driver;
#ifdef CONFIG_CPU_IDLE_THERMAL
int cpuidle_cooling_register(struct cpuidle_driver *drv);
-int cpuidle_of_cooling_register(struct device_node *np,
- struct cpuidle_driver *drv);
#else /* CONFIG_CPU_IDLE_THERMAL */
static inline int cpuidle_cooling_register(struct cpuidle_driver *drv)
{
return 0;
}
-static inline int cpuidle_of_cooling_register(struct device_node *np,
- struct cpuidle_driver *drv)
-{
- return 0;
-}
#endif /* CONFIG_CPU_IDLE_THERMAL */
#endif /* __CPU_COOLING_H__ */
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 4/4] thermal: cpuidle: Register cpuidle cooling device
2020-04-14 16:26 [PATCH v2 1/4] powercap/drivers/idle_inject: Specify idle state max latency Daniel Lezcano
2020-04-14 16:26 ` [PATCH v2 2/4] dt-bindings: thermal: Add the idle cooling device Daniel Lezcano
2020-04-14 16:26 ` [PATCH v2 3/4] thermal/drivers/cpuidle_cooling: Change the registration function Daniel Lezcano
@ 2020-04-14 16:26 ` Daniel Lezcano
2 siblings, 0 replies; 6+ messages in thread
From: Daniel Lezcano @ 2020-04-14 16:26 UTC (permalink / raw)
To: daniel.lezcano, rui.zhang
Cc: amit.kucheria, Rafael J. Wysocki, Lorenzo Pieralisi,
Sudeep Holla, open list:CPU IDLE TIME MANAGEMENT FRAMEWORK,
open list, open list:CPUIDLE DRIVER - ARM PSCI
The cpuidle driver can be used as a cooling device by injecting idle
cycles. The DT binding for the idle state added an optional
When the property is set, register the cpuidle driver with the idle
state node pointer as a cooling device. The thermal framework will do
the association automatically with the thermal zone via the
cooling-device defined in the device tree cooling-maps section.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
drivers/cpuidle/cpuidle-arm.c | 5 +++++
drivers/cpuidle/cpuidle-psci.c | 5 +++++
2 files changed, 10 insertions(+)
diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c
index 9e5156d39627..2406ac0ae134 100644
--- a/drivers/cpuidle/cpuidle-arm.c
+++ b/drivers/cpuidle/cpuidle-arm.c
@@ -8,6 +8,7 @@
#define pr_fmt(fmt) "CPUidle arm: " fmt
+#include <linux/cpu_cooling.h>
#include <linux/cpuidle.h>
#include <linux/cpumask.h>
#include <linux/cpu_pm.h>
@@ -124,6 +125,10 @@ static int __init arm_idle_init_cpu(int cpu)
if (ret)
goto out_kfree_drv;
+ ret = cpuidle_cooling_register(drv);
+ if (ret)
+ pr_err("Failed to register the idle cooling device: %d\n", ret);
+
return 0;
out_kfree_drv:
diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
index edd7a54ef0d3..8e805bff646f 100644
--- a/drivers/cpuidle/cpuidle-psci.c
+++ b/drivers/cpuidle/cpuidle-psci.c
@@ -9,6 +9,7 @@
#define pr_fmt(fmt) "CPUidle PSCI: " fmt
#include <linux/cpuhotplug.h>
+#include <linux/cpu_cooling.h>
#include <linux/cpuidle.h>
#include <linux/cpumask.h>
#include <linux/cpu_pm.h>
@@ -305,6 +306,10 @@ static int __init psci_idle_init_cpu(int cpu)
if (ret)
goto out_kfree_drv;
+ ret = cpuidle_cooling_register(drv);
+ if (ret)
+ pr_err("Failed to register the idle cooling device: %d\n", ret);
+
return 0;
out_kfree_drv:
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread