[PATCH 057/112] ACPI: register ACPI Processor as generic thermal cooling device

Len Brown
2008-02-07T09:36:11Z

From: Zhang Rui <rui.zhang@intel.com>

Register ACPI processor as thermal cooling devices.
A combination of processor T-state and P-state are used for thermal throttling.
the processor will reduce the frequency first and then set the T-state.

we use cpufreq_thermal_reduction_pctg to calculate the cpufreq limit,
and call cpufreq_verify_with_limit to set the cpufreq limit.
if cpufreq driver is loaded, then we have four cooling state for cpufreq control.
cooling state 0: cpufreq limit == max_freq
cooling state 1: cpufreq limit == max_freq * 80%
cooling state 2: cpufreq limit == max_freq * 60%
cooling state 3: cpufreq limit == max_freq * 40%

after the cpufreq limit is set to 40 percentage of the max_freq,
we use T-state for cooling.

eg. a processor has P-state support, and it has 8 T-state (T0-T7),
the max_state of the proceesor is 10:

state cpufreq-limit T-state
0: max_freq T0
1: max_freq * 80% T0
2: max_freq * 60% T0
3: max_freq * 40% T0
4: max_freq * 40% T1
5: max_freq * 40% T2
6: max_freq * 40% T3
7: max_freq * 40% T4
8: max_freq * 40% T5
9: max_freq * 40% T6
10: max_freq * 40% T7

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Thomas Sujith <sujith.thomas@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
---
drivers/acpi/processor_core.c | 23 +++++++
drivers/acpi/processor_thermal.c | 134 ++++++++++++++++++++++++++++++++++++--
include/acpi/processor.h | 6 +-
3 files changed, 155 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index e48ee4f..5668c5e 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -668,6 +668,24 @@ static int __cpuinit acpi_processor_start(struct acpi_device *device)

acpi_processor_power_init(pr, device);

+ pr->cdev = thermal_cooling_device_register("Processor", device,
+ &processor_cooling_ops);
+ if (pr->cdev)
+ printk(KERN_INFO PREFIX
+ "%s is registered as cooling_device%d\n",
+ device->dev.bus_id, pr->cdev->id);
+ else
+ goto end;
+
+ result = sysfs_create_link(&device->dev.kobj, &pr->cdev->device.kobj,
+ "thermal_cooling");
+ if (result)
+ return result;
+ result = sysfs_create_link(&pr->cdev->device.kobj, &device->dev.kobj,
+ "device");
+ if (result)
+ return result;
+
if (pr->flags.throttling) {
printk(KERN_INFO PREFIX "%s [%s] (supports",
acpi_device_name(device), acpi_device_bid(device));
@@ -791,6 +809,11 @@ static int acpi_processor_remove(struct acpi_device *device, int type)

acpi_processor_remove_fs(device);

+ sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
+ sysfs_remove_link(&pr->cdev->device.kobj, "device");
+ thermal_cooling_device_unregister(pr->cdev);
+ pr->cdev = NULL;
+
processors[pr->id] = NULL;

kfree(pr);
diff --git a/drivers/acpi/processor_thermal.c b/drivers/acpi/processor_thermal.c
index 06e6f3f..9cb43f5 100644
--- a/drivers/acpi/processor_thermal.c
+++ b/drivers/acpi/processor_thermal.c
@@ -32,6 +32,7 @@
#include <linux/cpufreq.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
+#include <linux/sysdev.h>

#include <asm/uaccess.h>

@@ -93,6 +94,9 @@ static int acpi_processor_apply_limit(struct acpi_processor *pr)
* _any_ cpufreq driver and not only the acpi-cpufreq driver.
*/

+#define CPUFREQ_THERMAL_MIN_STEP 0
+#define CPUFREQ_THERMAL_MAX_STEP 3
+
static unsigned int cpufreq_thermal_reduction_pctg[NR_CPUS];
static unsigned int acpi_thermal_cpufreq_is_init = 0;

@@ -109,8 +113,9 @@ static int acpi_thermal_cpufreq_increase(unsigned int cpu)
if (!cpu_has_cpufreq(cpu))
return -ENODEV;

- if (cpufreq_thermal_reduction_pctg[cpu] < 60) {
- cpufreq_thermal_reduction_pctg[cpu] += 20;
+ if (cpufreq_thermal_reduction_pctg[cpu] <
+ CPUFREQ_THERMAL_MAX_STEP) {
+ cpufreq_thermal_reduction_pctg[cpu]++;
cpufreq_update_policy(cpu);
return 0;
}
@@ -123,8 +128,9 @@ static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
if (!cpu_has_cpufreq(cpu))
return -ENODEV;

- if (cpufreq_thermal_reduction_pctg[cpu] > 20)
- cpufreq_thermal_reduction_pctg[cpu] -= 20;
+ if (cpufreq_thermal_reduction_pctg[cpu] >
+ (CPUFREQ_THERMAL_MIN_STEP + 1))
+ cpufreq_thermal_reduction_pctg[cpu]--;
else
cpufreq_thermal_reduction_pctg[cpu] = 0;
cpufreq_update_policy(cpu);
@@ -143,7 +149,7 @@ static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,

max_freq =
(policy->cpuinfo.max_freq *
- (100 - cpufreq_thermal_reduction_pctg[policy->cpu])) / 100;
+ (100 - cpufreq_thermal_reduction_pctg[policy->cpu] * 20)) / 100;

cpufreq_verify_within_limits(policy, 0, max_freq);

@@ -155,6 +161,32 @@ static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
.notifier_call = acpi_thermal_cpufreq_notifier,
};

+static int cpufreq_get_max_state(unsigned int cpu)
+{
+ if (!cpu_has_cpufreq(cpu))
+ return 0;
+
+ return CPUFREQ_THERMAL_MAX_STEP;
+}
+
+static int cpufreq_get_cur_state(unsigned int cpu)
+{
+ if (!cpu_has_cpufreq(cpu))
+ return 0;
+
+ return cpufreq_thermal_reduction_pctg[cpu];
+}
+
+static int cpufreq_set_cur_state(unsigned int cpu, int state)
+{
+ if (!cpu_has_cpufreq(cpu))
+ return 0;
+
+ cpufreq_thermal_reduction_pctg[cpu] = state;
+ cpufreq_update_policy(cpu);
+ return 0;
+}
+
void acpi_thermal_cpufreq_init(void)
{
int i;
@@ -179,6 +211,20 @@ void acpi_thermal_cpufreq_exit(void)
}

#else /* ! CONFIG_CPU_FREQ */
+static int cpufreq_get_max_state(unsigned int cpu)
+{
+ return 0;
+}
+
+static int cpufreq_get_cur_state(unsigned int cpu)
+{
+ return 0;
+}
+
+static int cpufreq_set_cur_state(unsigned int cpu, int state)
+{
+ return 0;
+}

static int acpi_thermal_cpufreq_increase(unsigned int cpu)
{
@@ -310,6 +356,84 @@ int acpi_processor_get_limit_info(struct acpi_processor *pr)
return 0;
}

+/* thermal coolign device callbacks */
+static int acpi_processor_max_state(struct acpi_processor *pr)
+{
+ int max_state = 0;
+
+ /*
+ * There exists four states according to
+ * cpufreq_thermal_reduction_ptg. 0, 1, 2, 3
+ */
+ max_state += cpufreq_get_max_state(pr->id);
+ if (pr->flags.throttling)
+ max_state += (pr->throttling.state_count -1);
+
+ return max_state;
+}
+static int
+processor_get_max_state(struct thermal_cooling_device *cdev, char *buf)
+{
+ struct acpi_device *device = cdev->devdata;
+ struct acpi_processor *pr = acpi_driver_data(device);
+
+ if (!device || !pr)
+ return -EINVAL;
+
+ return sprintf(buf, "%d\n", acpi_processor_max_state(pr));
+}
+
+static int
+processor_get_cur_state(struct thermal_cooling_device *cdev, char *buf)
+{
+ struct acpi_device *device = cdev->devdata;
+ struct acpi_processor *pr = acpi_driver_data(device);
+ int cur_state;
+
+ if (!device || !pr)
+ return -EINVAL;
+
+ cur_state = cpufreq_get_cur_state(pr->id);
+ if (pr->flags.throttling)
+ cur_state += pr->throttling.state;
+
+ return sprintf(buf, "%d\n", cur_state);
+}
+
+static int
+processor_set_cur_state(struct thermal_cooling_device *cdev, unsigned int state)
+{
+ struct acpi_device *device = cdev->devdata;
+ struct acpi_processor *pr = acpi_driver_data(device);
+ int result = 0;
+ int max_pstate;
+
+ if (!device || !pr)
+ return -EINVAL;
+
+ max_pstate = cpufreq_get_max_state(pr->id);
+
+ if (state > acpi_processor_max_state(pr))
+ return -EINVAL;
+
+ if (state <= max_pstate) {
+ if (pr->flags.throttling && pr->throttling.state)
+ result = acpi_processor_set_throttling(pr, 0);
+ cpufreq_set_cur_state(pr->id, state);
+ } else {
+ cpufreq_set_cur_state(pr->id, max_pstate);
+ result = acpi_processor_set_throttling(pr,
+ state - max_pstate);
+ }
+ return result;
+}
+
+struct thermal_cooling_device_ops processor_cooling_ops = {
+ .get_max_state = processor_get_max_state,
+ .get_cur_state = processor_get_cur_state,
+ .set_cur_state = processor_set_cur_state,
+};
+
/* /proc interface */

static int acpi_processor_limit_seq_show(struct seq_file *seq, void *offset)
diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index 76411b1..0787635 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -4,7 +4,7 @@
#include <linux/kernel.h>
#include <linux/cpu.h>
#include <linux/cpuidle.h>
-
+#include <linux/thermal.h>
#include <asm/acpi.h>

#define ACPI_PROCESSOR_BUSY_METRIC 10
@@ -218,7 +218,7 @@ struct acpi_processor {
struct acpi_processor_performance *performance;
struct acpi_processor_throttling throttling;
struct acpi_processor_limit limit;
-
+ struct thermal_cooling_device *cdev;
/* the _PDC objects for this processor, if any */
struct acpi_object_list *pdc;
};
@@ -330,7 +330,7 @@ extern struct cpuidle_driver acpi_idle_driver;
/* in processor_thermal.c */
int acpi_processor_get_limit_info(struct acpi_processor *pr);
extern struct file_operations acpi_processor_limit_fops;
-
+extern struct thermal_cooling_device_ops processor_cooling_ops;
#ifdef CONFIG_CPU_FREQ
void acpi_thermal_cpufreq_init(void);
void acpi_thermal_cpufreq_exit(void);
--
1.5.4.23.gef5b9