[PATCH 3/3] soc: ti: Add ti_sci_pm_domains driver

[Nishanth Menon]

From: Dave Gerlach <d-gerlach@xxxxxx>

Introduce a ti_sci_pm_domains to act as a generic pm domain provider to
allow each device to map into it's own genpd and be controlled through
the TI SCI protocol.

This driver implements a onecell genpd where each device node will have
a phandle to the power domain node and an index which represents the ID
to be passed with TI SCI representing the device. Through this interface
the power_on and power_off hooks within the driver will use TI SCI to
turn on and off hardware blocks as determined by pm_runtime usage.

This includes contributions by Andrew F. Davis <afd@xxxxxx>

Signed-off-by: Keerthy <j-keerthy@xxxxxx>
Signed-off-by: Dave Gerlach <d-gerlach@xxxxxx>
Signed-off-by: Nishanth Menon <nm@xxxxxx>
---
 MAINTAINERS                        |   1 +
 arch/arm/mach-keystone/Kconfig     |   1 +
 drivers/soc/ti/Kconfig             |  12 ++
 drivers/soc/ti/Makefile            |   1 +
 drivers/soc/ti/ti_sci_pm_domains.c | 222 +++++++++++++++++++++++++++++++++++++
 5 files changed, 237 insertions(+)
 create mode 100644 drivers/soc/ti/ti_sci_pm_domains.c

diff --git a/MAINTAINERS b/MAINTAINERS
index ea14b08c30bb..448f6801bd78 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11575,6 +11575,7 @@ F:	drivers/firmware/ti_sci*
 F:	include/linux/soc/ti/ti_sci_protocol.h
 F:	Documentation/devicetree/bindings/soc/ti/sci-pm-domain.txt
 F:	include/dt-bindings/genpd/k2g.h
+F:	drivers/soc/ti/ti_sci_pm_domains.c
 
 THANKO'S RAREMONO AM/FM/SW RADIO RECEIVER USB DRIVER
 M:	Hans Verkuil <hverkuil@xxxxxxxxx>
diff --git a/arch/arm/mach-keystone/Kconfig b/arch/arm/mach-keystone/Kconfig
index 8ff61be1a29f..34ef4b60adc6 100644
--- a/arch/arm/mach-keystone/Kconfig
+++ b/arch/arm/mach-keystone/Kconfig
@@ -11,6 +11,7 @@ config ARCH_KEYSTONE
 	select MIGHT_HAVE_PCI
 	select PCI_DOMAINS if PCI
 	select PINCTRL
+	select PM_GENERIC_DOMAINS if PM
 	help
 	  Support for boards based on the Texas Instruments Keystone family of
 	  SoCs.
diff --git a/drivers/soc/ti/Kconfig b/drivers/soc/ti/Kconfig
index 3557c5e32a93..39e152abe6b9 100644
--- a/drivers/soc/ti/Kconfig
+++ b/drivers/soc/ti/Kconfig
@@ -38,4 +38,16 @@ config WKUP_M3_IPC
 	  to communicate and use the Wakeup M3 for PM features like suspend
 	  resume and boots it using wkup_m3_rproc driver.
 
+config TI_SCI_PM_DOMAINS
+	tristate "TI SCI PM Domains Driver"
+	depends on TI_SCI_PROTOCOL
+	depends on PM_GENERIC_DOMAINS
+	help
+	  Generic power domain implementation for TI device implementing
+	  the TI SCI protocol.
+
+	  To compile this as a module, choose M here. The module will be
+	  called ti_sci_pm_domains. Note this is needed early in boot before
+	  rootfs may be available.
+
 endif # SOC_TI
diff --git a/drivers/soc/ti/Makefile b/drivers/soc/ti/Makefile
index 48ff3a79634f..7d572736c86e 100644
--- a/drivers/soc/ti/Makefile
+++ b/drivers/soc/ti/Makefile
@@ -5,3 +5,4 @@ obj-$(CONFIG_KEYSTONE_NAVIGATOR_QMSS)	+= knav_qmss.o
 knav_qmss-y := knav_qmss_queue.o knav_qmss_acc.o
 obj-$(CONFIG_KEYSTONE_NAVIGATOR_DMA)	+= knav_dma.o
 obj-$(CONFIG_WKUP_M3_IPC)		+= wkup_m3_ipc.o
+obj-$(CONFIG_TI_SCI_PM_DOMAINS)		+= ti_sci_pm_domains.o
diff --git a/drivers/soc/ti/ti_sci_pm_domains.c b/drivers/soc/ti/ti_sci_pm_domains.c
new file mode 100644
index 000000000000..ab6b20201731
--- /dev/null
+++ b/drivers/soc/ti/ti_sci_pm_domains.c
@@ -0,0 +1,222 @@
+/*
+ * TI SCI Generic Power Domain Driver
+ *
+ * Copyright (C) 2015-2016 Texas Instruments Incorporated - http://www.ti.com/
+ *	J Keerthy <j-keerthy@xxxxxx>
+ *	Dave Gerlach <d-gerlach@xxxxxx>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/slab.h>
+#include <linux/soc/ti/ti_sci_protocol.h>
+
+#define TI_GENPD_NAME_LENGTH	16
+
+/**
+ * struct ti_sci_genpd_data: holds data needed for every power domain
+ * @ti_sci: handle to TI SCI protocol driver that provides ops to
+ *	    communicate with system control processor.
+ * @dev: pointer to dev for the driver for devm allocs
+ * @pd_list_mutex: Mutex for protecting the global list of power domains
+ * @pd_list: list that hols all power domains as they are allocated
+ */
+struct ti_sci_genpd_data {
+	const struct ti_sci_handle *ti_sci;
+	struct device *dev;
+	struct mutex pd_list_mutex; /* Protect master list of domains */
+	struct list_head pd_list;
+};
+
+/**
+ * struct ti_sci_pm_domain: TI specific data needed for each power domain
+ * @idx: index of the power domain that identifies it with the system
+ *	 control processor.
+ * @pd: generic_pm_domain for use with the genpd framework
+ * @node: list_head for tracking all domains in a list
+ * @parent: pointer to the global data defined for all domains
+ */
+struct ti_sci_pm_domain {
+	int idx;
+	struct generic_pm_domain pd;
+	struct list_head node;
+	struct ti_sci_genpd_data *parent;
+};
+
+#define genpd_to_ti_sci_pd(gpd) container_of(gpd, struct ti_sci_pm_domain, pd)
+
+/**
+ * pd_power_off(): generic_pm_domain power_off hook
+ * @domain: generic_pm_domain struct provided by genpd framework of the
+ *	    pd to be shut off
+ *
+ * This hook uses the put_device dev_op provided by ti_sci to power off the
+ * device associated to the power domain provided.
+ */
+static int pd_power_off(struct generic_pm_domain *domain)
+{
+	struct ti_sci_pm_domain *ti_sci_pd = genpd_to_ti_sci_pd(domain);
+	const struct ti_sci_handle *ti_sci = ti_sci_pd->parent->ti_sci;
+
+	return ti_sci->ops.dev_ops.put_device(ti_sci,
+					      ti_sci_pd->idx);
+}
+
+/**
+ * pd_power_on(): generic_pm_domain power_on hook
+ * @domain: generic_pm_domain struct provided by genpd framework of the
+ *	    pd to be powered on
+ *
+ * This hook uses the get_device dev_op provided by ti_sci to power on the
+ * device associated to the power domain provided.
+ */
+static int pd_power_on(struct generic_pm_domain *domain)
+{
+	struct ti_sci_pm_domain *ti_sci_pd = genpd_to_ti_sci_pd(domain);
+	const struct ti_sci_handle *ti_sci = ti_sci_pd->parent->ti_sci;
+
+	return ti_sci->ops.dev_ops.get_device(ti_sci,
+					      ti_sci_pd->idx);
+}
+
+/**
+ * of_ti_sci_genpd_xlate_onecell() - Xlate function using a single index.
+ * @genpdspec: OF phandle args to define an index to be communicated over
+ *	       TI SCI to the system control processor to identify it
+ * @data: xlate function private data - pointer to the ti_sci_genpd_data
+ *	  struct containing global sci pm domain data
+ *
+ * This is xlate function takes a single cell as an index representing the
+ * id to be passed to the system control processor. As each device in the
+ * device tree probes a single pm domain will be created specifically for it
+ * based on the index passed in the pweor-domains property. If no pm domain
+ * yet exists for that index it is created, otherwise it is looked up and
+ * returned. Through this 1 to 1 association between power domains and
+ * devices the genpd framework will work to directly control devices
+ * through the pm_runtime framework.
+ */
+static struct generic_pm_domain *of_ti_sci_genpd_xlate_onecell(
+					struct of_phandle_args *genpdspec,
+					void *data)
+{
+	struct ti_sci_genpd_data *ti_sci_genpd = data;
+	const struct ti_sci_handle *ti_sci = ti_sci_genpd->ti_sci;
+	struct device *dev = ti_sci_genpd->dev;
+	unsigned int idx = genpdspec->args[0];
+	struct ti_sci_pm_domain *ti_sci_pd = NULL, *pd;
+	char *name;
+	int ret = 0;
+
+	if (genpdspec->args_count != 1)
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * Check the validity of the requested idx, if the index is not valid
+	 * the PMMC will return a NAK here and we will not allocate it.
+	 */
+	ret = ti_sci->ops.dev_ops.is_valid(ti_sci, idx);
+	if (ret)
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&ti_sci_genpd->pd_list_mutex);
+	list_for_each_entry(pd, &ti_sci_genpd->pd_list, node) {
+		if (pd->idx == idx) {
+			ti_sci_pd = pd;
+			goto unlock_and_return;
+		}
+	}
+
+	ti_sci_pd = devm_kzalloc(dev,
+				 sizeof(*ti_sci_pd),
+				 GFP_KERNEL);
+	if (!ti_sci_pd) {
+		ret = -ENOMEM;
+		goto unlock_and_return;
+	}
+
+	ti_sci_pd->idx = idx;
+	ti_sci_pd->pd.power_off = pd_power_off;
+	ti_sci_pd->pd.power_on = pd_power_on;
+
+	name = devm_kzalloc(dev, TI_GENPD_NAME_LENGTH, GFP_KERNEL);
+	if (!name) {
+		devm_kfree(dev, ti_sci_pd);
+		ret = -ENOMEM;
+		goto unlock_and_return;
+	}
+
+	snprintf(name, TI_GENPD_NAME_LENGTH, "pd-%d", idx);
+	ti_sci_pd->pd.name = name;
+
+	ti_sci_pd->parent = ti_sci_genpd;
+	/*
+	 * Init each pd as is_off so we always call pd_power_on
+	 * to make sure reference counting is properly maintained
+	 * on the SCI side
+	 */
+	pm_genpd_init(&ti_sci_pd->pd, NULL, true);
+
+	list_add(&ti_sci_pd->node, &ti_sci_genpd->pd_list);
+
+unlock_and_return:
+	mutex_unlock(&ti_sci_genpd->pd_list_mutex);
+
+	if (ret)
+		return ERR_PTR(ret);
+	else
+		return &ti_sci_pd->pd;
+}
+
+static const struct of_device_id ti_sci_pm_domain_matches[] = {
+	{ .compatible = "ti,sci-pm-domains", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, ti_sci_pm_domain_matches);
+
+static int ti_sci_pm_domains_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct ti_sci_genpd_data *ti_sci_genpd;
+
+	ti_sci_genpd = devm_kzalloc(dev, sizeof(*ti_sci_genpd), GFP_KERNEL);
+	if (!ti_sci_genpd)
+		return -ENOMEM;
+
+	ti_sci_genpd->ti_sci = devm_ti_sci_get_handle(dev);
+	if (IS_ERR(ti_sci_genpd->ti_sci))
+		return PTR_ERR(ti_sci_genpd->ti_sci);
+
+	ti_sci_genpd->dev = dev;
+
+	INIT_LIST_HEAD(&ti_sci_genpd->pd_list);
+	mutex_init(&ti_sci_genpd->pd_list_mutex);
+
+	return __of_genpd_add_provider(np, of_ti_sci_genpd_xlate_onecell,
+				       ti_sci_genpd);
+}
+
+static struct platform_driver ti_sci_pm_domains_driver = {
+	.probe = ti_sci_pm_domains_probe,
+	.driver = {
+		.name = "ti_sci_pm_domains",
+		.of_match_table = ti_sci_pm_domain_matches,
+	},
+};
+module_platform_driver(ti_sci_pm_domains_driver);
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("TI System Control Interface(SCI) Power Domain driver");
+MODULE_AUTHOR("Dave Gerlach");
-- 
2.9.1.200.gb1ec08f