Date:   Tue, 10 Sep 2019 13:14:35 -0400
From:   Thara Gopinath <thara.gopinath@...aro.org>
To:     edubezval@...il.com, rui.zhang@...el.com, ulf.hansson@...aro.org,
        daniel.lezcano@...aro.org, bjorn.andersson@...aro.org,
        robh+dt@...nel.org, agross@...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 4/5] thermal: Add generic power domain warming device driver.

Resources modeled as power domains in linux kenrel
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>
---
v1->v2:
	- Make power domain based warming device driver a generic
	driver in the thermal framework. v1 implemented this as a
	Qualcomm specific driver.
	- Rename certain variables as per review suggestions on the
	mailing list.

 drivers/thermal/Kconfig              |  11 +++
 drivers/thermal/Makefile             |   2 +
 drivers/thermal/pwr_domain_warming.c | 174 +++++++++++++++++++++++++++++++++++
 3 files changed, 187 insertions(+)
 create mode 100644 drivers/thermal/pwr_domain_warming.c

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 9966364..eeb6018 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -187,6 +187,17 @@ 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
+	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 74a37c7..382c64a 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -27,6 +27,8 @@ thermal_sys-$(CONFIG_CLOCK_THERMAL)	+= clock_cooling.o
 # devfreq cooling
 thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o
 
+thermal_sys-$(CONFIG_PWR_DOMAIN_WARMING_THERMAL)	+= pwr_domain_warming.o
+
 # platform thermal drivers
 obj-y				+= broadcom/
 obj-$(CONFIG_THERMAL_MMIO)		+= thermal_mmio.o
diff --git a/drivers/thermal/pwr_domain_warming.c b/drivers/thermal/pwr_domain_warming.c
new file mode 100644
index 0000000..3dd792b
--- /dev/null
+++ b/drivers/thermal/pwr_domain_warming.c
@@ -0,0 +1,174 @@
+// 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_domain.h>
+#include <linux/pm_runtime.h>
+#include <linux/thermal.h>
+
+struct pd_warming_device {
+	struct thermal_cooling_device *cdev;
+	struct device *dev;
+	int max_state;
+	int cur_state;
+	bool runtime_resumed;
+};
+
+static const struct of_device_id pd_wdev_match_table[] = {
+	{ .compatible = "thermal-power-domain-wdev", .data = NULL },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, pd_wdev_match_table);
+
+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 int pd_wdev_create(struct device *dev, const char *name)
+{
+	struct pd_warming_device *pd_wdev;
+	int state_count;
+
+	pd_wdev = devm_kzalloc(dev, sizeof(*pd_wdev), GFP_KERNEL);
+	if (!pd_wdev)
+		return -ENOMEM;
+
+	state_count = dev_pm_genpd_performance_state_count(dev);
+	if (state_count < 0)
+		return state_count;
+
+	pd_wdev->dev = dev;
+	pd_wdev->max_state = state_count - 1;
+	pd_wdev->runtime_resumed = false;
+
+	pm_runtime_enable(dev);
+
+	pd_wdev->cdev = thermal_of_cooling_device_register
+					(dev->of_node, name,
+					 pd_wdev,
+					 &pd_warming_device_ops);
+	if (IS_ERR(pd_wdev->cdev)) {
+		dev_err(dev, "unable to register %s cooling device\n", name);
+		pm_runtime_disable(dev);
+
+		return PTR_ERR(pd_wdev->cdev);
+	}
+
+	return 0;
+}
+
+static int pd_wdev_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev, *pd_dev;
+	const char *pd_name;
+	int id, count, ret = 0;
+
+	count = of_count_phandle_with_args(dev->of_node, "power-domains",
+					   "#power-domain-cells");
+
+	if (count > 1) {
+		for (id = 0; id < count; id++) {
+			ret = of_property_read_string_index
+					(dev->of_node, "power-domain-names",
+					 id, &pd_name);
+			if (ret) {
+				dev_err(dev, "Error reading the power domain name %d\n", ret);
+				continue;
+			}
+
+			pd_dev = dev_pm_domain_attach_by_id(dev, id);
+			if (IS_ERR(pd_dev)) {
+				dev_err(dev, "Error attaching power domain %s %ld\n", pd_name, PTR_ERR(pd_dev));
+				continue;
+			}
+
+			ret = pd_wdev_create(pd_dev, pd_name);
+			if (ret) {
+				dev_err(dev, "Error building cooling device %s %d\n", pd_name, ret);
+				dev_pm_domain_detach(pd_dev, false);
+				continue;
+			}
+		}
+	} else if (count == 1) {
+		ret = of_property_read_string_index(dev->of_node,
+						    "power-domain-names",
+						    0, &pd_name);
+		if (ret) {
+			dev_err(dev, "Error reading the power domain name %d\n", ret);
+			goto exit;
+		}
+
+		ret = pd_wdev_create(dev, pd_name);
+		if (ret) {
+			dev_err(dev, "Error building cooling device %s %d\n", pd_name, ret);
+			goto exit;
+		}
+	} else	{
+		ret = -EINVAL;
+	}
+
+exit:
+	return ret;
+}
+
+static struct platform_driver pd_wdev_driver = {
+	.driver = {
+		.name = "qcom-rpmhpd-cdev",
+		.of_match_table = pd_wdev_match_table,
+	},
+	.probe = pd_wdev_probe,
+};
+module_platform_driver(pd_wdev_driver);
+
+MODULE_DESCRIPTION("Qualcomm RPMHPD cooling device driver");
+MODULE_LICENSE("GPL v2");
-- 
2.1.4

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