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>

4 files changed, 204 insertions, 0 deletions

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index e91d78fff430..cb7d15c43f87 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -102,6 +102,13 @@ config IMX_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
         bool "SPEAr thermal sensor driver"
         depends on PLAT_SPEAR
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 6910b2dfb667..0177697798fa 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_DOVE_THERMAL)  	+= dove_thermal.o
 obj-$(CONFIG_DB8500_THERMAL)    += db8500_thermal.o
 obj-$(CONFIG_ARMADA_THERMAL)    += armada_thermal.o
 obj-$(CONFIG_IMX_THERMAL)       += imx_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
 
diff --git a/drivers/thermal/device_cooling.c b/drivers/thermal/device_cooling.c
new file mode 100644
index 000000000000..1c223a88bc1a
--- /dev/null
+++ b/drivers/thermal/device_cooling.c
@@ -0,0 +1,151 @@
+/*
+ * Copyright (C) 2013 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);
diff --git a/include/linux/device_cooling.h b/include/linux/device_cooling.h
new file mode 100644
index 000000000000..ae40a451e4fa
--- /dev/null
+++ b/include/linux/device_cooling.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2013 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.
+ *
+ */
+
+#ifndef __DEVICE_THERMAL_H__
+#define __DEVICE_THERMAL_H__
+
+#include <linux/thermal.h>
+
+#ifdef CONFIG_DEVICE_THERMAL
+int register_devfreq_cooling_notifier(struct notifier_block *nb);
+int unregister_devfreq_cooling_notifier(struct notifier_block *nb);
+struct thermal_cooling_device *devfreq_cooling_register(void);
+void devfreq_cooling_unregister(struct thermal_cooling_device *cdev);
+#else
+static inline
+int register_devfreq_cooling_notifier(struct notifier_block *nb)
+{
+        return 0;
+}
+
+static inline
+int unregister_devfreq_cooling_notifier(struct notifier_block *nb)
+{
+        return 0;
+}
+
+static inline
+struct thermal_cooling_device *devfreq_cooling_register(void)
+{
+        return NULL;
+}
+
+static inline
+void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
+{
+        return;
+}
+#endif
+#endif /* __DEVICE_THERMAL_H__ */