MLK-11485 thermal: add device cooling for thermal driver

this patch is chery-picked from imx_3.14.y
(cherry picked from commit 51e376b469c)
ENGR00274056-1 thermal: add device cooling for thermal driver

cpu cooling is not enough when temperature is
too hot, as some devices may contribute a lot of heat
to SOC, such as GPU, so we need to add device cooling
as well, when system is too hot, devices can also take
their actions to lower SOC temperature.

when temperature cross the passive trip, device cooling
driver will send out notification, those devices who
register this devfreq_cooling notification will take
actions to lower SOC temperature.

Signed-off-by: Anson Huang <b20788@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: Bai Ping <b51503@freescale.com>

3 files changed, 159 insertions, 0 deletions

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 6356295672cb..9e35c5161a02 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -215,6 +215,13 @@ config QORIQ_THERMAL
 	  cpufreq is used as the cooling device to throttle CPUs when the
 	  passive trip is crossed.
 
+config DEVICE_THERMAL
+	tristate "generic device cooling support"
+	help
+	  Support for device cooling.
+	  It supports notification of crossing passive trip for devices,
+	  devices need to do their own actions to cool down the SOC.
+
 config SPEAR_THERMAL
 	tristate "SPEAr thermal sensor driver"
 	depends on PLAT_SPEAR || COMPILE_TEST
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index c92eb22a41ff..842efac4711f 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_TANGO_THERMAL)	+= tango_thermal.o
 obj-$(CONFIG_IMX_THERMAL)	+= imx_thermal.o
 obj-$(CONFIG_MAX77620_THERMAL)	+= max77620_thermal.o
 obj-$(CONFIG_QORIQ_THERMAL)	+= qoriq_thermal.o
+obj-$(CONFIG_DEVICE_THERMAL)	+= device_cooling.o
 obj-$(CONFIG_DB8500_CPUFREQ_COOLING)	+= db8500_cpufreq_cooling.o
 obj-$(CONFIG_INTEL_POWERCLAMP)	+= intel_powerclamp.o
 obj-$(CONFIG_X86_PKG_TEMP_THERMAL)	+= x86_pkg_temp_thermal.o
diff --git a/drivers/thermal/device_cooling.c b/drivers/thermal/device_cooling.c
new file mode 100644
index 000000000000..844b074a2532
--- /dev/null
+++ b/drivers/thermal/device_cooling.c
@@ -0,0 +1,151 @@
+/*
+ * Copyright (C) 2013-2015 Freescale Semiconductor, Inc.
+ *
+ * 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/module.h>
+#include <linux/thermal.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+
+struct devfreq_cooling_device {
+	int id;
+	struct thermal_cooling_device *cool_dev;
+	unsigned int devfreq_state;
+};
+
+static DEFINE_IDR(devfreq_idr);
+static DEFINE_MUTEX(devfreq_cooling_lock);
+
+#define	MAX_STATE	1
+
+static BLOCKING_NOTIFIER_HEAD(devfreq_cooling_chain_head);
+
+int register_devfreq_cooling_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(
+		&devfreq_cooling_chain_head, nb);
+}
+EXPORT_SYMBOL_GPL(register_devfreq_cooling_notifier);
+
+int unregister_devfreq_cooling_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(
+		&devfreq_cooling_chain_head, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_devfreq_cooling_notifier);
+
+static int devfreq_cooling_notifier_call_chain(unsigned long val)
+{
+	return (blocking_notifier_call_chain(
+		&devfreq_cooling_chain_head, val, NULL)
+		== NOTIFY_BAD) ? -EINVAL : 0;
+}
+
+static int devfreq_set_cur_state(struct thermal_cooling_device *cdev,
+				 unsigned long state)
+{
+	struct devfreq_cooling_device *devfreq_device = cdev->devdata;
+	int ret;
+
+	ret = devfreq_cooling_notifier_call_chain(state);
+	if (ret)
+		return -EINVAL;
+	devfreq_device->devfreq_state = state;
+
+	return 0;
+}
+
+static int devfreq_get_max_state(struct thermal_cooling_device *cdev,
+				 unsigned long *state)
+{
+	*state = MAX_STATE;
+
+	return 0;
+}
+
+static int devfreq_get_cur_state(struct thermal_cooling_device *cdev,
+				 unsigned long *state)
+{
+	struct devfreq_cooling_device *devfreq_device = cdev->devdata;
+
+	*state = devfreq_device->devfreq_state;
+
+	return 0;
+}
+
+static struct thermal_cooling_device_ops const devfreq_cooling_ops = {
+	.get_max_state = devfreq_get_max_state,
+	.get_cur_state = devfreq_get_cur_state,
+	.set_cur_state = devfreq_set_cur_state,
+};
+
+static int get_idr(struct idr *idr, int *id)
+{
+	int ret;
+
+	mutex_lock(&devfreq_cooling_lock);
+	ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL);
+	mutex_unlock(&devfreq_cooling_lock);
+	if (unlikely(ret < 0))
+		return ret;
+	*id = ret;
+
+	return 0;
+}
+
+static void release_idr(struct idr *idr, int id)
+{
+	mutex_lock(&devfreq_cooling_lock);
+	idr_remove(idr, id);
+	mutex_unlock(&devfreq_cooling_lock);
+}
+
+struct thermal_cooling_device *devfreq_cooling_register(void)
+{
+	struct thermal_cooling_device *cool_dev;
+	struct devfreq_cooling_device *devfreq_dev = NULL;
+	char dev_name[THERMAL_NAME_LENGTH];
+	int ret = 0;
+
+	devfreq_dev = kzalloc(sizeof(struct devfreq_cooling_device),
+			      GFP_KERNEL);
+	if (!devfreq_dev)
+		return ERR_PTR(-ENOMEM);
+
+	ret = get_idr(&devfreq_idr, &devfreq_dev->id);
+	if (ret) {
+		kfree(devfreq_dev);
+		return ERR_PTR(-EINVAL);
+	}
+
+	snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d",
+		 devfreq_dev->id);
+
+	cool_dev = thermal_cooling_device_register(dev_name, devfreq_dev,
+						   &devfreq_cooling_ops);
+	if (!cool_dev) {
+		release_idr(&devfreq_idr, devfreq_dev->id);
+		kfree(devfreq_dev);
+		return ERR_PTR(-EINVAL);
+	}
+	devfreq_dev->cool_dev = cool_dev;
+	devfreq_dev->devfreq_state = 0;
+
+	return cool_dev;
+}
+EXPORT_SYMBOL_GPL(devfreq_cooling_register);
+
+void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
+{
+	struct devfreq_cooling_device *devfreq_dev = cdev->devdata;
+
+	thermal_cooling_device_unregister(devfreq_dev->cool_dev);
+	release_idr(&devfreq_idr, devfreq_dev->id);
+	kfree(devfreq_dev);
+}
+EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);