[PATCH v3 3/3] soc: qcom: apr: Add avs/audio tracking functionality

[Sibi Sankar <sibis@codeaurora.org>]

Use PDR helper functions to track the protection domains that the apr
services are dependent upon on SDM845 SoC, specifically the "avs/audio"
service running on ADSP Q6.

Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
---
 drivers/soc/qcom/Kconfig     |   1 +
 drivers/soc/qcom/apr.c       | 100 +++++++++++++++++++++++++++++++----
 include/linux/soc/qcom/apr.h |   1 +
 3 files changed, 91 insertions(+), 11 deletions(-)

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 5c4e76837f59b..cacfed945b275 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -202,6 +202,7 @@ config QCOM_APR
 	tristate "Qualcomm APR Bus (Asynchronous Packet Router)"
 	depends on ARCH_QCOM || COMPILE_TEST
 	depends on RPMSG
+	select QCOM_PDR_HELPERS
 	help
           Enable APR IPC protocol support between
           application processor and QDSP6. APR is
diff --git a/drivers/soc/qcom/apr.c b/drivers/soc/qcom/apr.c
index 4fcc32420c474..5234426718e88 100644
--- a/drivers/soc/qcom/apr.c
+++ b/drivers/soc/qcom/apr.c
@@ -11,6 +11,7 @@
 #include <linux/workqueue.h>
 #include <linux/of_device.h>
 #include <linux/soc/qcom/apr.h>
+#include <linux/soc/qcom/pdr.h>
 #include <linux/rpmsg.h>
 #include <linux/of.h>
 
@@ -21,6 +22,7 @@ struct apr {
 	spinlock_t rx_lock;
 	struct idr svcs_idr;
 	int dest_domain_id;
+	struct pdr_handle pdr;
 	struct workqueue_struct *rxwq;
 	struct work_struct rx_work;
 	struct list_head rx_list;
@@ -289,6 +291,9 @@ static int apr_add_device(struct device *dev, struct device_node *np,
 		  id->svc_id + 1, GFP_ATOMIC);
 	spin_unlock(&apr->svcs_lock);
 
+	of_property_read_string_index(np, "qcom,protection-domain",
+				      1, &adev->service_path);
+
 	dev_info(dev, "Adding APR dev: %s\n", dev_name(&adev->dev));
 
 	ret = device_register(&adev->dev);
@@ -300,14 +305,56 @@ static int apr_add_device(struct device *dev, struct device_node *np,
 	return ret;
 }
 
-static void of_register_apr_devices(struct device *dev)
+static void of_apr_add_pd_lookups(struct device *dev)
 {
+	const char *service_name, *service_path;
 	struct apr *apr = dev_get_drvdata(dev);
 	struct device_node *node;
+	int ret;
+
+	for_each_child_of_node(dev->of_node, node) {
+		ret = of_property_read_string_index(node, "qcom,protection-domain",
+						    0, &service_name);
+		if (ret < 0)
+			continue;
+
+		ret = of_property_read_string_index(node, "qcom,protection-domain",
+						    1, &service_path);
+		if (ret < 0)
+			continue;
+
+		ret = pdr_add_lookup(&apr->pdr, service_name, service_path);
+		if (ret && ret != -EALREADY)
+			dev_err(dev, "pdr add lookup failed: %d\n", ret);
+	}
+}
+
+static void of_register_apr_devices(struct device *dev, const char *svc_path)
+{
+	struct apr *apr = dev_get_drvdata(dev);
+	struct device_node *node;
+	const char *service_path;
+	int ret;
 
 	for_each_child_of_node(dev->of_node, node) {
 		struct apr_device_id id = { {0} };
 
+		ret = of_property_read_string_index(node, "qcom,protection-domain",
+						    1, &service_path);
+		if (svc_path) {
+			/* skip APR services that are PD independent */
+			if (ret)
+				continue;
+
+			/* skip APR services whose PD paths don't match */
+			if (strcmp(service_path, svc_path))
+				continue;
+		} else {
+			/* skip APR services whose PD lookups are registered */
+			if (ret == 0)
+				continue;
+		}
+
 		if (of_property_read_u32(node, "reg", &id.svc_id))
 			continue;
 
@@ -318,6 +365,35 @@ static void of_register_apr_devices(struct device *dev)
 	}
 }
 
+static int apr_remove_device(struct device *dev, void *svc_path)
+{
+	struct apr_device *adev = to_apr_device(dev);
+
+	if (svc_path) {
+		if (!strcmp(adev->service_path, (char *)svc_path))
+			device_unregister(&adev->dev);
+	} else {
+		device_unregister(&adev->dev);
+	}
+
+	return 0;
+}
+
+static void apr_pd_status(struct pdr_handle *pdr, struct pdr_service *pds)
+{
+	struct apr *apr = container_of(pdr, struct apr, pdr);
+
+	switch (pds->state) {
+	case SERVREG_SERVICE_STATE_UP:
+		of_register_apr_devices(apr->dev, pds->service_path);
+		break;
+	case SERVREG_SERVICE_STATE_DOWN:
+		device_for_each_child(apr->dev, pds->service_path,
+				      apr_remove_device);
+		break;
+	}
+}
+
 static int apr_probe(struct rpmsg_device *rpdev)
 {
 	struct device *dev = &rpdev->dev;
@@ -337,26 +413,27 @@ static int apr_probe(struct rpmsg_device *rpdev)
 	dev_set_drvdata(dev, apr);
 	apr->ch = rpdev->ept;
 	apr->dev = dev;
+
 	apr->rxwq = create_singlethread_workqueue("qcom_apr_rx");
 	if (!apr->rxwq) {
 		dev_err(apr->dev, "Failed to start Rx WQ\n");
 		return -ENOMEM;
 	}
 	INIT_WORK(&apr->rx_work, apr_rxwq);
+
+	ret = pdr_handle_init(&apr->pdr, apr_pd_status);
+	if (ret) {
+		dev_err(dev, "Failed to init PDR handle\n");
+		destroy_workqueue(apr->rxwq);
+		return ret;
+	}
+
 	INIT_LIST_HEAD(&apr->rx_list);
 	spin_lock_init(&apr->rx_lock);
 	spin_lock_init(&apr->svcs_lock);
 	idr_init(&apr->svcs_idr);
-	of_register_apr_devices(dev);
-
-	return 0;
-}
-
-static int apr_remove_device(struct device *dev, void *null)
-{
-	struct apr_device *adev = to_apr_device(dev);
-
-	device_unregister(&adev->dev);
+	of_apr_add_pd_lookups(dev);
+	of_register_apr_devices(dev, NULL);
 
 	return 0;
 }
@@ -365,6 +442,7 @@ static void apr_remove(struct rpmsg_device *rpdev)
 {
 	struct apr *apr = dev_get_drvdata(&rpdev->dev);
 
+	pdr_handle_release(&apr->pdr);
 	device_for_each_child(&rpdev->dev, NULL, apr_remove_device);
 	flush_workqueue(apr->rxwq);
 	destroy_workqueue(apr->rxwq);
diff --git a/include/linux/soc/qcom/apr.h b/include/linux/soc/qcom/apr.h
index c5d52e2cb275f..7f0bc3cf4d610 100644
--- a/include/linux/soc/qcom/apr.h
+++ b/include/linux/soc/qcom/apr.h
@@ -85,6 +85,7 @@ struct apr_device {
 	uint16_t	domain_id;
 	uint32_t	version;
 	char name[APR_NAME_SIZE];
+	const char *service_path;
 	spinlock_t	lock;
 	struct list_head node;
 };
-- 
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