Message-Id: <20200320014107.26087-4-thara.gopinath@linaro.org>
Date:   Thu, 19 Mar 2020 21:41:04 -0400
From:   Thara Gopinath <thara.gopinath@...aro.org>
To:     rui.zhang@...el.com, ulf.hansson@...aro.org,
        daniel.lezcano@...aro.org, bjorn.andersson@...aro.org,
        agross@...nel.org, robh@...nel.org
Cc:     amit.kucheria@...durent.com, mark.rutland@....com,
        rjw@...ysocki.net, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [Patch v5 3/6] thermal: Add generic power domain warming device driver.

Resources modeled as power domains in linux kernel can  be used to warm the
SoC(eg. mx power domain on sdm845).  To support this feature, introduce a
generic power domain warming device driver that can be plugged into the
thermal framework (The thermal framework itself requires further
modifiction to support a warming device in place of a cooling device.
Those extensions are not introduced in this patch series).

Signed-off-by: Thara Gopinath <thara.gopinath@...aro.org>
---

v3->v4:
	- Removed late_init hook pd_warming_device_ops.
	- Use of_genpd_add_device instead of pm_genpd_add_device to attach
	  device to the generic power domain.
	- Use thermal_of_cooling_device_parent_register to register the
	  cooling device so that the device with genpd attached can be
	  made parent of the cooling device.
	- With above changes, remove reference to generic_pm_domain in
	  pd_warming_device.

v4->v5:
	- All the below changes are as per Ulf's review comments.
	- Renamed pwr_domain_warming.c and pwr_domain_warming.h to
	  pd_warming.c and pd_warming.h.
	- Renamed pwr_domain_warming_register API to 
	  of_pd_warming_register.
	- Dropped in-param pd_name to of_pd_warming_register.
	- Introduced ID allocator to uniquely identify each power domain
	  warming device.
	- Introduced pd_warming_release to handle device kfree for
	  pd_warming_device.
	- Introduced pm_genpd_remove_device in the error exit path
	  of of_pd_warming_register.

 drivers/thermal/Kconfig      |  10 +++
 drivers/thermal/Makefile     |   2 +
 drivers/thermal/pd_warming.c | 168 +++++++++++++++++++++++++++++++++++
 include/linux/pd_warming.h   |  29 ++++++
 4 files changed, 209 insertions(+)
 create mode 100644 drivers/thermal/pd_warming.c
 create mode 100644 include/linux/pd_warming.h

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 4d6753f2b18f..92522d541d0e 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -206,6 +206,16 @@ config DEVFREQ_THERMAL
 
 	  If you want this support, you should say Y here.
 
+config PWR_DOMAIN_WARMING_THERMAL
+	bool "Power Domain based warming device"
+	depends on PM_GENERIC_DOMAINS_OF
+	help
+	  This implements the generic power domain based warming
+	  mechanism through increasing the performance state of
+	  a power domain.
+
+	  If you want this support, you should say Y here.
+
 config THERMAL_EMULATION
 	bool "Thermal emulation mode support"
 	help
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 8c8ed7b79915..7db87a779126 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -28,6 +28,8 @@ thermal_sys-$(CONFIG_CLOCK_THERMAL)	+= clock_cooling.o
 # devfreq cooling
 thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o
 
+thermal_sys-$(CONFIG_PWR_DOMAIN_WARMING_THERMAL)	+= pd_warming.o
+
 # platform thermal drivers
 obj-y				+= broadcom/
 obj-$(CONFIG_THERMAL_MMIO)		+= thermal_mmio.o
diff --git a/drivers/thermal/pd_warming.c b/drivers/thermal/pd_warming.c
new file mode 100644
index 000000000000..c0854d2e4b92
--- /dev/null
+++ b/drivers/thermal/pd_warming.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2019, Linaro Ltd
+ */
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/pd_warming.h>
+
+struct pd_warming_device {
+	struct thermal_cooling_device *cdev;
+	struct device dev;
+	int id;
+	int max_state;
+	int cur_state;
+	bool runtime_resumed;
+};
+
+static DEFINE_IDA(pd_ida);
+
+static int pd_wdev_get_max_state(struct thermal_cooling_device *cdev,
+				 unsigned long *state)
+{
+	struct pd_warming_device *pd_wdev = cdev->devdata;
+
+	*state = pd_wdev->max_state;
+	return 0;
+}
+
+static int pd_wdev_get_cur_state(struct thermal_cooling_device *cdev,
+				 unsigned long *state)
+{
+	struct pd_warming_device *pd_wdev = cdev->devdata;
+
+	*state = dev_pm_genpd_get_performance_state(&pd_wdev->dev);
+
+	return 0;
+}
+
+static int pd_wdev_set_cur_state(struct thermal_cooling_device *cdev,
+				 unsigned long state)
+{
+	struct pd_warming_device *pd_wdev = cdev->devdata;
+	struct device *dev = &pd_wdev->dev;
+	int ret;
+
+	ret = dev_pm_genpd_set_performance_state(dev, state);
+
+	if (ret)
+		return ret;
+
+	if (state && !pd_wdev->runtime_resumed) {
+		ret = pm_runtime_get_sync(dev);
+		pd_wdev->runtime_resumed = true;
+	} else if (!state && pd_wdev->runtime_resumed) {
+		ret = pm_runtime_put(dev);
+		pd_wdev->runtime_resumed = false;
+	}
+
+	return ret;
+}
+
+static struct thermal_cooling_device_ops pd_warming_device_ops = {
+	.get_max_state	= pd_wdev_get_max_state,
+	.get_cur_state	= pd_wdev_get_cur_state,
+	.set_cur_state	= pd_wdev_set_cur_state,
+};
+
+static void pd_warming_release(struct device *dev)
+{
+	kfree(dev);
+}
+
+struct thermal_cooling_device *
+of_pd_warming_register(struct device *parent, int pd_id)
+{
+	struct pd_warming_device *pd_wdev;
+	struct of_phandle_args pd_args;
+	char cdev_name[THERMAL_NAME_LENGTH];
+	int ret;
+
+	pd_wdev = kzalloc(sizeof(*pd_wdev), GFP_KERNEL);
+	if (!pd_wdev)
+		return ERR_PTR(-ENOMEM);
+
+	dev_set_name(&pd_wdev->dev, "%s_%d_warming_dev",
+		     dev_name(parent), pd_id);
+	pd_wdev->dev.parent = parent;
+	pd_wdev->dev.release = pd_warming_release;
+
+	ret = device_register(&pd_wdev->dev);
+	if (ret) {
+		put_device(&pd_wdev->dev);
+		goto free_pd_wdev;
+	}
+
+	ret = ida_simple_get(&pd_ida, 0, 0, GFP_KERNEL);
+	if (ret < 0)
+		goto unregister_device;
+
+	pd_wdev->id = ret;
+
+	pd_args.np = parent->of_node;
+	pd_args.args[0] = pd_id;
+	pd_args.args_count = 1;
+
+	ret = of_genpd_add_device(&pd_args, &pd_wdev->dev);
+
+	if (ret)
+		goto remove_ida;
+
+	ret = dev_pm_genpd_performance_state_count(&pd_wdev->dev);
+	if (ret < 0)
+		goto out_genpd;
+
+	pd_wdev->max_state = ret - 1;
+	pm_runtime_enable(&pd_wdev->dev);
+	pd_wdev->runtime_resumed = false;
+
+	snprintf(cdev_name, sizeof(cdev_name), "thermal-pd-%d", pd_wdev->id);
+	pd_wdev->cdev = thermal_of_cooling_device_register
+					(NULL, cdev_name, pd_wdev,
+					 &pd_warming_device_ops);
+	if (IS_ERR(pd_wdev->cdev)) {
+		pr_err("unable to register %s cooling device\n", cdev_name);
+		ret = PTR_ERR(pd_wdev->cdev);
+		goto out_runtime_disable;
+	}
+
+	return pd_wdev->cdev;
+
+out_runtime_disable:
+	pm_runtime_disable(&pd_wdev->dev);
+out_genpd:
+	pm_genpd_remove_device(&pd_wdev->dev);
+remove_ida:
+	ida_simple_remove(&pd_ida, pd_wdev->id);
+unregister_device:
+	device_unregister(&pd_wdev->dev);
+	pd_warming_release(&pd_wdev->dev);
+free_pd_wdev:
+	kfree(pd_wdev);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(of_pd_warming_register);
+
+void pd_warming_unregister(struct thermal_cooling_device *cdev)
+{
+	struct pd_warming_device *pd_wdev = cdev->devdata;
+	struct device *dev = &pd_wdev->dev;
+
+	if (pd_wdev->runtime_resumed) {
+		dev_pm_genpd_set_performance_state(dev, 0);
+		pm_runtime_put(dev);
+		pd_wdev->runtime_resumed = false;
+	}
+	pm_runtime_disable(dev);
+	pm_genpd_remove_device(dev);
+	ida_simple_remove(&pd_ida, pd_wdev->id);
+	thermal_cooling_device_unregister(cdev);
+	kfree(pd_wdev);
+}
+EXPORT_SYMBOL_GPL(pd_warming_unregister);
diff --git a/include/linux/pd_warming.h b/include/linux/pd_warming.h
new file mode 100644
index 000000000000..550a5683b56d
--- /dev/null
+++ b/include/linux/pd_warming.h
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2019, Linaro Ltd.
+ */
+#ifndef __PWR_DOMAIN_WARMING_H__
+#define __PWR_DOMAIN_WARMING_H__
+
+#include <linux/pm_domain.h>
+#include <linux/thermal.h>
+
+#ifdef CONFIG_PWR_DOMAIN_WARMING_THERMAL
+struct thermal_cooling_device *
+of_pd_warming_register(struct device *parent, int pd_id);
+
+void pd_warming_unregister(struct thermal_cooling_device *cdev);
+
+#else
+static inline struct thermal_cooling_device *
+of_pd_warming_register(struct device *parent, int pd_id)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline void
+pd_warming_unregister(struct thermal_cooling_device *cdev)
+{
+}
+#endif /* CONFIG_PWR_DOMAIN_WARMING_THERMAL */
+#endif /* __PWR_DOMAIN_WARMING_H__ */
-- 
2.20.1

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