[PATCH 2/2] drivers: soc: xilinx: Add ZynqMP power domain driver

[Jolly Shah]

The zynqmp-genpd driver communicates the usage requirements
for logical power domains / devices to the platform FW.
FW is responsible for choosing appropriate power states,
taking Linux' usage information into account.

Signed-off-by: Jolly Shah <jollys@xxxxxxxxxx>
Signed-off-by: Rajan Vaja <rajanv@xxxxxxxxxx>
---
 drivers/soc/xilinx/Kconfig             |   2 +
 drivers/soc/xilinx/Makefile            |   2 +
 drivers/soc/xilinx/zynqmp/Kconfig      |  16 ++
 drivers/soc/xilinx/zynqmp/Makefile     |   4 +
 drivers/soc/xilinx/zynqmp/pm_domains.c | 339 +++++++++++++++++++++++++++++++++
 5 files changed, 363 insertions(+)
 create mode 100644 drivers/soc/xilinx/zynqmp/Kconfig
 create mode 100644 drivers/soc/xilinx/zynqmp/Makefile
 create mode 100644 drivers/soc/xilinx/zynqmp/pm_domains.c

diff --git a/drivers/soc/xilinx/Kconfig b/drivers/soc/xilinx/Kconfig
index 687c8f3..1c98d7f 100644
--- a/drivers/soc/xilinx/Kconfig
+++ b/drivers/soc/xilinx/Kconfig
@@ -17,4 +17,6 @@ config XILINX_VCU
 	  To compile this driver as a module, choose M here: the
 	  module will be called xlnx_vcu.
 
+source "drivers/soc/xilinx/zynqmp/Kconfig"
+
 endmenu
diff --git a/drivers/soc/xilinx/Makefile b/drivers/soc/xilinx/Makefile
index dee8fd5..e132897 100644
--- a/drivers/soc/xilinx/Makefile
+++ b/drivers/soc/xilinx/Makefile
@@ -1,2 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_XILINX_VCU)	+= xlnx_vcu.o
+
+obj-$(CONFIG_ARCH_ZYNQMP)	+= zynqmp/
diff --git a/drivers/soc/xilinx/zynqmp/Kconfig b/drivers/soc/xilinx/zynqmp/Kconfig
new file mode 100644
index 0000000..95d8665
--- /dev/null
+++ b/drivers/soc/xilinx/zynqmp/Kconfig
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0+
+# Kconfig for Xilinx zynqmp SoC
+
+menu "Zynq MPSoC SoC Drivers"
+	depends on ARCH_ZYNQMP
+
+config ZYNQMP_PM_DOMAINS
+	bool "Enable Zynq MPSoC generic PM domains"
+	default y
+	depends on PM
+	select PM_GENERIC_DOMAINS
+	help
+	  Say yes to enable device power management through PM domains
+	  In doubt, say N
+
+endmenu
diff --git a/drivers/soc/xilinx/zynqmp/Makefile b/drivers/soc/xilinx/zynqmp/Makefile
new file mode 100644
index 0000000..0bd522b
--- /dev/null
+++ b/drivers/soc/xilinx/zynqmp/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0+
+# Makefile for Xilinx zynqmp SoC
+
+obj-$(CONFIG_ZYNQMP_PM_DOMAINS) += pm_domains.o
diff --git a/drivers/soc/xilinx/zynqmp/pm_domains.c b/drivers/soc/xilinx/zynqmp/pm_domains.c
new file mode 100644
index 0000000..7ddca8e
--- /dev/null
+++ b/drivers/soc/xilinx/zynqmp/pm_domains.c
@@ -0,0 +1,339 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * ZynqMP Generic PM domain support
+ *
+ *  Copyright (C) 2015-2018 Xilinx, Inc.
+ *
+ *  Davorin Mista <davorin.mista@xxxxxxxxxx>
+ *  Jolly Shah <jollys@xxxxxxxxxx>
+ *  Rajan Vaja <rajanv@xxxxxxxxxx>
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/firmware/xilinx/zynqmp/firmware.h>
+
+/* Flag stating if PM nodes mapped to the PM domain has been requested */
+#define ZYNQMP_PM_DOMAIN_REQUESTED	BIT(0)
+
+/**
+ * struct zynqmp_pm_domain - Wrapper around struct generic_pm_domain
+ * @gpd:		Generic power domain
+ * @dev_list:		List of devices belong to power domain
+ * @node_ids:		PM node IDs corresponding to device(s) inside PM domain
+ * @node_id_num:	Number of PM node IDs
+ * @flags:		ZynqMP PM domain flags
+ */
+struct zynqmp_pm_domain {
+	struct generic_pm_domain gpd;
+	struct list_head dev_list;
+	u32 *node_ids;
+	int node_id_num;
+	u8 flags;
+};
+
+/*
+ * struct zynqmp_domain_device - Device node present in power domain
+ * @dev: Device
+ * &list: List member for the devices in domain list
+ */
+struct zynqmp_domain_device {
+	struct device *dev;
+	struct list_head list;
+};
+
+/**
+ * zynqmp_gpd_is_active_wakeup_path - Check if device is in wakeup source path
+ * @dev: Device to check for wakeup source path
+ * @not_used: Data member (not required)
+ *
+ * This function is checks device's child hierarchy and checks if any device is
+ * set as wakeup source.
+ *
+ * Return:	1 if device is in wakeup source path else 0.
+ */
+static int zynqmp_gpd_is_active_wakeup_path(struct device *dev, void *not_used)
+{
+	int may_wakeup;
+
+	may_wakeup = device_may_wakeup(dev);
+	if (may_wakeup)
+		return may_wakeup;
+
+	return device_for_each_child(dev, NULL,
+			zynqmp_gpd_is_active_wakeup_path);
+}
+
+/**
+ * zynqmp_gpd_power_on - Power on PM domain
+ * @domain:	Generic PM domain
+ *
+ * This function is called before devices inside a PM domain are resumed, to
+ * power on PM domain.
+ *
+ * Return:	0 on success, error code otherwise.
+ */
+static int zynqmp_gpd_power_on(struct generic_pm_domain *domain)
+{
+	int i, status = 0;
+	struct zynqmp_pm_domain *pd;
+	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
+
+	if (!eemi_ops || !eemi_ops->set_requirement)
+		return status;
+
+	pd = container_of(domain, struct zynqmp_pm_domain, gpd);
+	for (i = 0; i < pd->node_id_num; i++) {
+		status = eemi_ops->set_requirement(pd->node_ids[i],
+					ZYNQMP_PM_CAPABILITY_ACCESS,
+					ZYNQMP_PM_MAX_QOS,
+					ZYNQMP_PM_REQUEST_ACK_BLOCKING);
+		if (status)
+			break;
+	}
+	return status;
+}
+
+/**
+ * zynqmp_gpd_power_off - Power off PM domain
+ * @domain:	Generic PM domain
+ *
+ * This function is called after devices inside a PM domain are suspended, to
+ * power off PM domain.
+ *
+ * Return:	0 on success, error code otherwise.
+ */
+static int zynqmp_gpd_power_off(struct generic_pm_domain *domain)
+{
+	int i, status = 0;
+	struct zynqmp_pm_domain *pd;
+	struct zynqmp_domain_device *zdev, *tmp;
+	u32 capabilities = 0;
+	bool may_wakeup = 0;
+	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
+
+	if (!eemi_ops || !eemi_ops->set_requirement)
+		return status;
+
+	pd = container_of(domain, struct zynqmp_pm_domain, gpd);
+
+	/* If domain is already released there is nothing to be done */
+	if (!(pd->flags & ZYNQMP_PM_DOMAIN_REQUESTED))
+		return 0;
+
+	list_for_each_entry_safe(zdev, tmp, &pd->dev_list, list) {
+		/* If device is in wakeup path, set capability to WAKEUP */
+		may_wakeup = zynqmp_gpd_is_active_wakeup_path(zdev->dev, NULL);
+		if (may_wakeup) {
+			dev_dbg(zdev->dev, "device is in wakeup path in %s\n",
+				domain->name);
+			capabilities = ZYNQMP_PM_CAPABILITY_WAKEUP;
+			break;
+		}
+	}
+
+	for (i = pd->node_id_num - 1; i >= 0; i--) {
+		status = eemi_ops->set_requirement(pd->node_ids[i],
+						   capabilities, 0,
+						   ZYNQMP_PM_REQUEST_ACK_NO);
+		/**
+		 * If powering down of any node inside this domain fails,
+		 * report and return the error
+		 */
+		if (status) {
+			pr_err("%s error %d, node %u\n", __func__, status,
+			       pd->node_ids[i]);
+			return status;
+		}
+	}
+
+	return status;
+}
+
+/**
+ * zynqmp_gpd_attach_dev - Attach device to the PM domain
+ * @domain:	Generic PM domain
+ * @dev:	Device to attach
+ *
+ * Return:	0 on success, error code otherwise.
+ */
+static int zynqmp_gpd_attach_dev(struct generic_pm_domain *domain,
+				 struct device *dev)
+{
+	int i, status;
+	struct zynqmp_pm_domain *pd;
+	struct zynqmp_domain_device *zdev;
+	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
+
+	if (!eemi_ops || !eemi_ops->request_node)
+		return -ENXIO;
+
+	pd = container_of(domain, struct zynqmp_pm_domain, gpd);
+
+	zdev = devm_kzalloc(dev, sizeof(*zdev), GFP_KERNEL);
+	if (!zdev)
+		return -ENOMEM;
+
+	zdev->dev = dev;
+	list_add(&zdev->list, &pd->dev_list);
+
+	/* If this is not the first device to attach there is nothing to do */
+	if (domain->device_count)
+		return 0;
+
+	for (i = 0; i < pd->node_id_num; i++) {
+		status = eemi_ops->request_node(pd->node_ids[i], 0, 0,
+						ZYNQMP_PM_REQUEST_ACK_BLOCKING);
+		/* If requesting a node fails print and return the error */
+		if (status) {
+			pr_err("%s error %d, node %u\n", __func__,
+			       status, pd->node_ids[i]);
+			list_del(&zdev->list);
+			zdev->dev = NULL;
+			devm_kfree(dev, zdev);
+			return status;
+		}
+	}
+
+	pd->flags |= ZYNQMP_PM_DOMAIN_REQUESTED;
+
+	return 0;
+}
+
+/**
+ * zynqmp_gpd_detach_dev - Detach device from the PM domain
+ * @domain:	Generic PM domain
+ * @dev:	Device to detach
+ */
+static void zynqmp_gpd_detach_dev(struct generic_pm_domain *domain,
+				  struct device *dev)
+{
+	int i, status;
+	struct zynqmp_pm_domain *pd;
+	struct zynqmp_domain_device *zdev, *tmp;
+	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
+
+	if (!eemi_ops || !eemi_ops->release_node)
+		return;
+
+	pd = container_of(domain, struct zynqmp_pm_domain, gpd);
+
+	list_for_each_entry_safe(zdev, tmp, &pd->dev_list, list)
+		if (zdev->dev == dev) {
+			list_del(&zdev->list);
+			zdev->dev = NULL;
+			devm_kfree(dev, zdev);
+		}
+
+	/* If this is not the last device to detach there is nothing to do */
+	if (domain->device_count)
+		return;
+
+	for (i = 0; i < pd->node_id_num; i++) {
+		status = eemi_ops->release_node(pd->node_ids[i]);
+		/* If releasing a node fails print the error and return */
+		if (status) {
+			pr_err("%s error %d, node %u\n", __func__, status,
+			       pd->node_ids[i]);
+			return;
+		}
+	}
+
+	pd->flags &= ~ZYNQMP_PM_DOMAIN_REQUESTED;
+}
+
+/**
+ * zynqmp_gpd_probe - Initialize ZynqMP specific PM domains
+ * @pdev:	Platform device pointer
+ *
+ * Description:	This function populates struct zynqmp_pm_domain for each PM
+ * domain and initalizes generic PM domain. If the "pd-id" DT property
+ * of a certain domain is missing or invalid, that domain will be skipped.
+ *
+ * Return:	0 on success, error code otherwise.
+ */
+static int __init zynqmp_gpd_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct device_node *child_err, *child, *np = pdev->dev.of_node;
+
+	for_each_child_of_node(np, child) {
+		struct zynqmp_pm_domain *pd;
+
+		pd = devm_kzalloc(&pdev->dev, sizeof(*pd), GFP_KERNEL);
+		if (!pd) {
+			ret = -ENOMEM;
+			goto err_cleanup;
+		}
+
+		ret = of_property_count_u32_elems(child, "pd-id");
+		if (ret <= 0)
+			goto err_cleanup;
+
+		pd->node_id_num = ret;
+		pd->node_ids = devm_kcalloc(&pdev->dev, ret,
+					    sizeof(*pd->node_ids), GFP_KERNEL);
+		if (!pd->node_ids) {
+			ret = -ENOMEM;
+			goto err_cleanup;
+		}
+
+		ret = of_property_read_u32_array(child, "pd-id", pd->node_ids,
+						 pd->node_id_num);
+		if (ret)
+			goto err_cleanup;
+
+		pd->gpd.name = kstrdup(child->name, GFP_KERNEL);
+		pd->gpd.power_off = zynqmp_gpd_power_off;
+		pd->gpd.power_on = zynqmp_gpd_power_on;
+		pd->gpd.attach_dev = zynqmp_gpd_attach_dev;
+		pd->gpd.detach_dev = zynqmp_gpd_detach_dev;
+
+		/* Mark all PM domains as initially powered off */
+		pm_genpd_init(&pd->gpd, NULL, true);
+
+		ret = of_genpd_add_provider_simple(child, &pd->gpd);
+		if (ret)
+			goto err_cleanup;
+
+		INIT_LIST_HEAD(&pd->dev_list);
+	}
+
+	return 0;
+
+err_cleanup:
+	child_err = child;
+	for_each_child_of_node(np, child) {
+		if (child == child_err)
+			break;
+		of_genpd_del_provider(child);
+	}
+
+	return ret;
+}
+
+static const struct of_device_id zynqmp_gpd_of_match[] = {
+	{ .compatible = "xlnx,zynqmp-genpd" },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, zynqmp_gpd_of_match);
+
+static struct platform_driver zynqmp_gpd_platform_driver = {
+	.driver	= {
+		.name = "zynqmp_gpd",
+		.of_match_table = zynqmp_gpd_of_match,
+	},
+};
+
+static __init int zynqmp_gpd_init(void)
+{
+	return platform_driver_probe(&zynqmp_gpd_platform_driver,
+				     zynqmp_gpd_probe);
+}
+subsys_initcall(zynqmp_gpd_init);
-- 
2.7.4