[PATCH v1 1/2] thermal: Add generic device cooling support

[Alice Guo (OSS)]

From: Anson Huang <Anson.Huang at nxp.com>

To compatible with previous implementation, add generic device
cooling support, each thermal zone will register a cooling
device, and when temperature exceed passive trip, the device
cooling driver will send out a system wide notification, each
device supporting cooling will need to register device cooling
and takes action when passive trip is exceeded;

Signed-off-by: Anson Huang <Anson.Huang at nxp.com>
Signed-off-by: Dong Aisheng <aisheng.dong at nxp.com>
Signed-off-by: Alice Guo <alice.guo at nxp.com>
---
 drivers/thermal/Kconfig          |   7 ++
 drivers/thermal/Makefile         |   1 +
 drivers/thermal/device_cooling.c | 154 +++++++++++++++++++++++++++++++
 include/linux/device_cooling.h   |  46 +++++++++
 4 files changed, 208 insertions(+)
 create mode 100644 drivers/thermal/device_cooling.c
 create mode 100644 include/linux/device_cooling.h

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index e052dae614eb..2625903b56f5 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -284,6 +284,13 @@ config K3_THERMAL
 
 	  This includes temperature reading functionality.
 
+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 MAX77620_THERMAL
 	tristate "Temperature sensor driver for Maxim MAX77620 PMIC"
 	depends on MFD_MAX77620
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 2506c6c8ca83..77c4b2e525a4 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_ARMADA_THERMAL)	+= armada_thermal.o
 obj-$(CONFIG_IMX_THERMAL)	+= imx_thermal.o
 obj-$(CONFIG_IMX_SC_THERMAL)	+= imx_sc_thermal.o
 obj-$(CONFIG_IMX8MM_THERMAL)	+= imx8mm_thermal.o
+obj-$(CONFIG_DEVICE_THERMAL)	+= device_cooling.o
 obj-$(CONFIG_MAX77620_THERMAL)	+= max77620_thermal.o
 obj-$(CONFIG_QORIQ_THERMAL)	+= qoriq_thermal.o
 obj-$(CONFIG_DA9062_THERMAL)	+= da9062-thermal.o
diff --git a/drivers/thermal/device_cooling.c b/drivers/thermal/device_cooling.c
new file mode 100644
index 000000000000..6bd668ee545e
--- /dev/null
+++ b/drivers/thermal/device_cooling.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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.
+ *
+ * Copyright 2023 NXP
+ */
+
+#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 const struct thermal_cooling_device_ops 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..83b709e7c893
--- /dev/null
+++ b/include/linux/device_cooling.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * 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.
+ *
+ * Copyright 2023 NXP
+ */
+
+#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 ERR_PTR(-EINVAL);
+}
+
+static inline
+void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
+{
+}
+#endif
+#endif /* __DEVICE_THERMAL_H__ */
-- 
2.17.1