soc: ti: Add ti_sci_pm_domains driver

Introduce a ti_sci_pm_domains driver to act as a generic pm domain
provider to allow each device to attach and associate it's ti-sci-id so
that it can be controlled through the TI SCI protocol.

This driver implements a simple genpd where each device node has a
phandle to the power domain node and also must provide an index which
represents the ID to be passed with TI SCI representing the device using
a single phandle cell. The driver manually parses the phandle to get the
cell value. Through this interface the genpd dev_ops start and stop
hooks will use TI SCI to turn on and off each device as determined by
pm_runtime usage.

Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Santosh Shilimkar <ssantosh@kernel.org>

MAINTAINERS

@@ -12384,6 +12384,7 @@ 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@xs4all.nl>

arch/arm/mach-keystone/Kconfig

@@ -10,6 +10,7 @@ config ARCH_KEYSTONE
 	select ARCH_SUPPORTS_BIG_ENDIAN
 	select ZONE_DMA if ARM_LPAE
 	select PINCTRL
+	select PM_GENERIC_DOMAINS if PM
 	help
 	  Support for boards based on the Texas Instruments Keystone family of
 	  SoCs.

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

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

drivers/soc/ti/ti_sci_pm_domains.c

@@ -0,0 +1,202 @@
+/*
+ * TI SCI Generic Power Domain Driver
+ *
+ * Copyright (C) 2015-2017 Texas Instruments Incorporated - https://urldefense.proofpoint.com/v2/url?u=http-3A__www.ti.com_&d=DwIBAg&c=RoP1YumCXCgaWHvlZYR8PQcxBKCX5YTpkKY057SbK10&r=XBn1JQGPwR8CsE7xpP3wPlG6DQU7qw8ym65xieNZ4hY&m=R6qGiR9DbG1C3EF_0mL-m-qkmSO64GklbFWpUzqt8fY&s=YTWcQCWi5lnIf4XHDLq1XDd4JbZv9xpqOwdPD8xEdZE&e=
+ *	J Keerthy <j-keerthy@ti.com>
+ *	Dave Gerlach <d-gerlach@ti.com>
+ *
+ * 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>
+
+/**
+ * struct ti_sci_genpd_dev_data: holds data needed for every device attached
+ *				 to this genpd
+ * @idx: index of the device that identifies it with the system
+ *	 control processor.
+ */
+struct ti_sci_genpd_dev_data {
+	int idx;
+};
+
+/**
+ * struct ti_sci_pm_domain: TI specific data needed for 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: generic_pm_domain for use with the genpd framework
+ */
+struct ti_sci_pm_domain {
+	const struct ti_sci_handle *ti_sci;
+	struct device *dev;
+	struct generic_pm_domain pd;
+};
+
+#define genpd_to_ti_sci_pd(gpd) container_of(gpd, struct ti_sci_pm_domain, pd)
+
+/**
+ * ti_sci_dev_id(): get prepopulated ti_sci id from struct dev
+ * @dev: pointer to device associated with this genpd
+ *
+ * Returns device_id stored from ti,sci_id property
+ */
+static int ti_sci_dev_id(struct device *dev)
+{
+	struct generic_pm_domain_data *genpd_data = dev_gpd_data(dev);
+	struct ti_sci_genpd_dev_data *sci_dev_data = genpd_data->data;
+
+	return sci_dev_data->idx;
+}
+
+/**
+ * ti_sci_dev_to_sci_handle(): get pointer to ti_sci_handle
+ * @dev: pointer to device associated with this genpd
+ *
+ * Returns ti_sci_handle to be used to communicate with system
+ *	   control processor.
+ */
+static const struct ti_sci_handle *ti_sci_dev_to_sci_handle(struct device *dev)
+{
+	struct generic_pm_domain *pd = pd_to_genpd(dev->pm_domain);
+	struct ti_sci_pm_domain *ti_sci_genpd = genpd_to_ti_sci_pd(pd);
+
+	return ti_sci_genpd->ti_sci;
+}
+
+/**
+ * ti_sci_dev_start(): genpd device start hook called to turn device on
+ * @dev: pointer to device associated with this genpd to be powered on
+ */
+static int ti_sci_dev_start(struct device *dev)
+{
+	const struct ti_sci_handle *ti_sci = ti_sci_dev_to_sci_handle(dev);
+	int idx = ti_sci_dev_id(dev);
+
+	return ti_sci->ops.dev_ops.get_device(ti_sci, idx);
+}
+
+/**
+ * ti_sci_dev_stop(): genpd device stop hook called to turn device off
+ * @dev: pointer to device associated with this genpd to be powered off
+ */
+static int ti_sci_dev_stop(struct device *dev)
+{
+	const struct ti_sci_handle *ti_sci = ti_sci_dev_to_sci_handle(dev);
+	int idx = ti_sci_dev_id(dev);
+
+	return ti_sci->ops.dev_ops.put_device(ti_sci, idx);
+}
+
+static int ti_sci_pd_attach_dev(struct generic_pm_domain *domain,
+				struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	struct of_phandle_args pd_args;
+	struct ti_sci_pm_domain *ti_sci_genpd = genpd_to_ti_sci_pd(domain);
+	const struct ti_sci_handle *ti_sci = ti_sci_genpd->ti_sci;
+	struct ti_sci_genpd_dev_data *sci_dev_data;
+	struct generic_pm_domain_data *genpd_data;
+	int idx, ret = 0;
+
+	ret = of_parse_phandle_with_args(np, "power-domains",
+					 "#power-domain-cells", 0, &pd_args);
+	if (ret < 0)
+		return ret;
+
+	if (pd_args.args_count != 1)
+		return -EINVAL;
+
+	idx = pd_args.args[0];
+
+	/*
+	 * 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 -EINVAL;
+
+	sci_dev_data = kzalloc(sizeof(*sci_dev_data), GFP_KERNEL);
+	if (!sci_dev_data)
+		return -ENOMEM;
+
+	sci_dev_data->idx = idx;
+
+	genpd_data = dev_gpd_data(dev);
+	genpd_data->data = sci_dev_data;
+
+	return 0;
+}
+
+static void ti_sci_pd_detach_dev(struct generic_pm_domain *domain,
+				 struct device *dev)
+{
+	struct generic_pm_domain_data *genpd_data = dev_gpd_data(dev);
+	struct ti_sci_genpd_dev_data *sci_dev_data = genpd_data->data;
+
+	kfree(sci_dev_data);
+	genpd_data->data = NULL;
+}
+
+static const struct of_device_id ti_sci_pm_domain_matches[] = {
+	{ .compatible = "ti,sci-pm-domain", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, ti_sci_pm_domain_matches);
+
+static int ti_sci_pm_domain_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct ti_sci_pm_domain *ti_sci_pd;
+	int ret;
+
+	ti_sci_pd = devm_kzalloc(dev, sizeof(*ti_sci_pd), GFP_KERNEL);
+	if (!ti_sci_pd)
+		return -ENOMEM;
+
+	ti_sci_pd->ti_sci = devm_ti_sci_get_handle(dev);
+	if (IS_ERR(ti_sci_pd->ti_sci))
+		return PTR_ERR(ti_sci_pd->ti_sci);
+
+	ti_sci_pd->dev = dev;
+
+	ti_sci_pd->pd.attach_dev = ti_sci_pd_attach_dev;
+	ti_sci_pd->pd.detach_dev = ti_sci_pd_detach_dev;
+
+	ti_sci_pd->pd.dev_ops.start = ti_sci_dev_start;
+	ti_sci_pd->pd.dev_ops.stop = ti_sci_dev_stop;
+
+	pm_genpd_init(&ti_sci_pd->pd, NULL, true);
+
+	ret = of_genpd_add_provider_simple(np, &ti_sci_pd->pd);
+
+	return ret;
+}
+
+static struct platform_driver ti_sci_pm_domains_driver = {
+	.probe = ti_sci_pm_domain_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");