[PATCH 4/5] thermal: Add generic power domain warming device driver.

Thara Gopinath
2019-09-10T17:14:53Z

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@linaro.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