drivers/soc/qcom/apr.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2011-2017, The Linux Foundation. All rights reserved.
 // Copyright (c) 2018, Linaro Limited

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/spinlock.h>
 #include <linux/idr.h>
 #include <linux/slab.h>
 #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>

 struct apr {
 	struct rpmsg_endpoint *ch;
 	struct device *dev;
 	spinlock_t svcs_lock;
 	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;
 };

 struct apr_rx_buf {
 	struct list_head node;
 	int len;
 	uint8_t buf[];
 };

 /**
  * apr_send_pkt() - Send a apr message from apr device
  *
  * @adev: Pointer to previously registered apr device.
  * @pkt: Pointer to apr packet to send
  *
  * Return: Will be an negative on packet size on success.
  */
 int apr_send_pkt(struct apr_device *adev, struct apr_pkt *pkt)
 {
 	struct apr *apr = dev_get_drvdata(adev->dev.parent);
 	struct apr_hdr *hdr;
 	unsigned long flags;
 	int ret;

 	spin_lock_irqsave(&adev->lock, flags);

 	hdr = &pkt->hdr;
 	hdr->src_domain = APR_DOMAIN_APPS;
 	hdr->src_svc = adev->svc_id;
 	hdr->dest_domain = adev->domain_id;
 	hdr->dest_svc = adev->svc_id;

 	ret = rpmsg_trysend(apr->ch, pkt, hdr->pkt_size);
 	spin_unlock_irqrestore(&adev->lock, flags);

 	return ret ? ret : hdr->pkt_size;
 }
 EXPORT_SYMBOL_GPL(apr_send_pkt);

 static void apr_dev_release(struct device *dev)
 {
 	struct apr_device *adev = to_apr_device(dev);

 	kfree(adev);
 }

 static int apr_callback(struct rpmsg_device *rpdev, void *buf,
 				  int len, void *priv, u32 addr)
 {
 	struct apr *apr = dev_get_drvdata(&rpdev->dev);
 	struct apr_rx_buf *abuf;
 	unsigned long flags;

 	if (len <= APR_HDR_SIZE) {
 		dev_err(apr->dev, "APR: Improper apr pkt received:%p %d\n",
 			buf, len);
 		return -EINVAL;
 	}

 	abuf = kzalloc(sizeof(*abuf) + len, GFP_ATOMIC);
 	if (!abuf)
 		return -ENOMEM;

 	abuf->len = len;
 	memcpy(abuf->buf, buf, len);

 	spin_lock_irqsave(&apr->rx_lock, flags);
 	list_add_tail(&abuf->node, &apr->rx_list);
 	spin_unlock_irqrestore(&apr->rx_lock, flags);

 	queue_work(apr->rxwq, &apr->rx_work);

 	return 0;
 }


 static int apr_do_rx_callback(struct apr *apr, struct apr_rx_buf *abuf)
 {
 	uint16_t hdr_size, msg_type, ver, svc_id;
 	struct apr_device *svc = NULL;
 	struct apr_driver *adrv = NULL;
 	struct apr_resp_pkt resp;
 	struct apr_hdr *hdr;
 	unsigned long flags;
 	void *buf = abuf->buf;
 	int len = abuf->len;

 	hdr = buf;
 	ver = APR_HDR_FIELD_VER(hdr->hdr_field);
 	if (ver > APR_PKT_VER + 1)
 		return -EINVAL;

 	hdr_size = APR_HDR_FIELD_SIZE_BYTES(hdr->hdr_field);
 	if (hdr_size < APR_HDR_SIZE) {
 		dev_err(apr->dev, "APR: Wrong hdr size:%d\n", hdr_size);
 		return -EINVAL;
 	}

 	if (hdr->pkt_size < APR_HDR_SIZE || hdr->pkt_size != len) {
 		dev_err(apr->dev, "APR: Wrong packet size\n");
 		return -EINVAL;
 	}

 	msg_type = APR_HDR_FIELD_MT(hdr->hdr_field);
 	if (msg_type >= APR_MSG_TYPE_MAX) {
 		dev_err(apr->dev, "APR: Wrong message type: %d\n", msg_type);
 		return -EINVAL;
 	}

 	if (hdr->src_domain >= APR_DOMAIN_MAX ||
 			hdr->dest_domain >= APR_DOMAIN_MAX ||
 			hdr->src_svc >= APR_SVC_MAX ||
 			hdr->dest_svc >= APR_SVC_MAX) {
 		dev_err(apr->dev, "APR: Wrong APR header\n");
 		return -EINVAL;
 	}

 	svc_id = hdr->dest_svc;
 	spin_lock_irqsave(&apr->svcs_lock, flags);
 	svc = idr_find(&apr->svcs_idr, svc_id);
 	if (svc && svc->dev.driver)
 		adrv = to_apr_driver(svc->dev.driver);
 	spin_unlock_irqrestore(&apr->svcs_lock, flags);

 	if (!adrv) {
 		dev_err(apr->dev, "APR: service is not registered\n");
 		return -EINVAL;
 	}

 	resp.hdr = *hdr;
 	resp.payload_size = hdr->pkt_size - hdr_size;

 	/*
 	 * NOTE: hdr_size is not same as APR_HDR_SIZE as remote can include
 	 * optional headers in to apr_hdr which should be ignored
 	 */
 	if (resp.payload_size > 0)
 		resp.payload = buf + hdr_size;

 	adrv->callback(svc, &resp);

 	return 0;
 }

 static void apr_rxwq(struct work_struct *work)
 {
 	struct apr *apr = container_of(work, struct apr, rx_work);
 	struct apr_rx_buf *abuf, *b;
 	unsigned long flags;

 	if (!list_empty(&apr->rx_list)) {
 		list_for_each_entry_safe(abuf, b, &apr->rx_list, node) {
 			apr_do_rx_callback(apr, abuf);
 			spin_lock_irqsave(&apr->rx_lock, flags);
 			list_del(&abuf->node);
 			spin_unlock_irqrestore(&apr->rx_lock, flags);
 			kfree(abuf);
 		}
 	}
 }

 static int apr_device_match(struct device *dev, struct device_driver *drv)
 {
 	struct apr_device *adev = to_apr_device(dev);
 	struct apr_driver *adrv = to_apr_driver(drv);
 	const struct apr_device_id *id = adrv->id_table;

 	/* Attempt an OF style match first */
 	if (of_driver_match_device(dev, drv))
 		return 1;

 	if (!id)
 		return 0;

 	while (id->domain_id != 0 || id->svc_id != 0) {
 		if (id->domain_id == adev->domain_id &&
 		    id->svc_id == adev->svc_id)
 			return 1;
 		id++;
 	}

 	return 0;
 }

 static int apr_device_probe(struct device *dev)
 {
 	struct apr_device *adev = to_apr_device(dev);
 	struct apr_driver *adrv = to_apr_driver(dev->driver);

 	return adrv->probe(adev);
 }

 static int apr_device_remove(struct device *dev)
 {
 	struct apr_device *adev = to_apr_device(dev);
 	struct apr_driver *adrv;
 	struct apr *apr = dev_get_drvdata(adev->dev.parent);

 	if (dev->driver) {
 		adrv = to_apr_driver(dev->driver);
 		if (adrv->remove)
 			adrv->remove(adev);
 		spin_lock(&apr->svcs_lock);
 		idr_remove(&apr->svcs_idr, adev->svc_id);
 		spin_unlock(&apr->svcs_lock);
 	}

 	return 0;
 }

 static int apr_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct apr_device *adev = to_apr_device(dev);
 	int ret;

 	ret = of_device_uevent_modalias(dev, env);
 	if (ret != -ENODEV)
 		return ret;

 	return add_uevent_var(env, "MODALIAS=apr:%s", adev->name);
 }

 struct bus_type aprbus = {
 	.name		= "aprbus",
 	.match		= apr_device_match,
 	.probe		= apr_device_probe,
 	.uevent		= apr_uevent,
 	.remove		= apr_device_remove,
 };
 EXPORT_SYMBOL_GPL(aprbus);

 static int apr_add_device(struct device *dev, struct device_node *np,
 			  const struct apr_device_id *id)
 {
 	struct apr *apr = dev_get_drvdata(dev);
 	struct apr_device *adev = NULL;
 	int ret;

 	adev = kzalloc(sizeof(*adev), GFP_KERNEL);
 	if (!adev)
 		return -ENOMEM;

 	spin_lock_init(&adev->lock);

 	adev->svc_id = id->svc_id;
 	adev->domain_id = id->domain_id;
 	adev->version = id->svc_version;
 	if (np)
 		snprintf(adev->name, APR_NAME_SIZE, "%pOFn", np);
 	else
 		strscpy(adev->name, id->name, APR_NAME_SIZE);

 	dev_set_name(&adev->dev, "aprsvc:%s:%x:%x", adev->name,
 		     id->domain_id, id->svc_id);

 	adev->dev.bus = &aprbus;
 	adev->dev.parent = dev;
 	adev->dev.of_node = np;
 	adev->dev.release = apr_dev_release;
 	adev->dev.driver = NULL;

 	spin_lock(&apr->svcs_lock);
 	idr_alloc(&apr->svcs_idr, adev, id->svc_id,
 		  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);
 	if (ret) {
 		dev_err(dev, "device_register failed: %d\n", ret);
 		put_device(&adev->dev);
 	}

 	return ret;
 }

 static int 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;
 	struct pdr_service *pds;
 	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) {
 			dev_err(dev, "pdr service path missing: %d\n", ret);
 			return ret;
 		}

 		pds = pdr_add_lookup(apr->pdr, service_name, service_path);
 		if (IS_ERR(pds) && PTR_ERR(pds) != -EALREADY) {
 			dev_err(dev, "pdr add lookup failed: %ld\n", PTR_ERR(pds));
 			return PTR_ERR(pds);
 		}
 	}

 	return 0;
 }

 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} };

 		/*
 		 * This function is called with svc_path NULL during
 		 * apr_probe(), in which case we register any apr devices
 		 * without a qcom,protection-domain specified.
 		 *
 		 * Then as the protection domains becomes available
 		 * (if applicable) this function is again called, but with
 		 * svc_path representing the service becoming available. In
 		 * this case we register any apr devices with a matching
 		 * qcom,protection-domain.
 		 */

 		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;

 		id.domain_id = apr->dest_domain_id;

 		if (apr_add_device(dev, node, &id))
 			dev_err(dev, "Failed to add apr %d svc\n", id.svc_id);
 	}
 }

 static int apr_remove_device(struct device *dev, void *svc_path)
 {
 	struct apr_device *adev = to_apr_device(dev);

 	if (svc_path && adev->service_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(int state, char *svc_path, void *priv)
 {
 	struct apr *apr = (struct apr *)priv;

 	switch (state) {
 	case SERVREG_SERVICE_STATE_UP:
 		of_register_apr_devices(apr->dev, svc_path);
 		break;
 	case SERVREG_SERVICE_STATE_DOWN:
 		device_for_each_child(apr->dev, svc_path, apr_remove_device);
 		break;
 	}
 }

 static int apr_probe(struct rpmsg_device *rpdev)
 {
 	struct device *dev = &rpdev->dev;
 	struct apr *apr;
 	int ret;

 	apr = devm_kzalloc(dev, sizeof(*apr), GFP_KERNEL);
 	if (!apr)
 		return -ENOMEM;

 	ret = of_property_read_u32(dev->of_node, "qcom,apr-domain", &apr->dest_domain_id);
 	if (ret) {
 		dev_err(dev, "APR Domain ID not specified in DT\n");
 		return ret;
 	}

 	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);

 	apr->pdr = pdr_handle_alloc(apr_pd_status, apr);
 	if (IS_ERR(apr->pdr)) {
 		dev_err(dev, "Failed to init PDR handle\n");
 		ret = PTR_ERR(apr->pdr);
 		goto destroy_wq;
 	}

 	INIT_LIST_HEAD(&apr->rx_list);
 	spin_lock_init(&apr->rx_lock);
 	spin_lock_init(&apr->svcs_lock);
 	idr_init(&apr->svcs_idr);

 	ret = of_apr_add_pd_lookups(dev);
 	if (ret)
 		goto handle_release;

 	of_register_apr_devices(dev, NULL);

 	return 0;

 handle_release:
 	pdr_handle_release(apr->pdr);
 destroy_wq:
 	destroy_workqueue(apr->rxwq);
 	return ret;
 }

 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);
 }

 /*
  * __apr_driver_register() - Client driver registration with aprbus
  *
  * @drv:Client driver to be associated with client-device.
  * @owner: owning module/driver
  *
  * This API will register the client driver with the aprbus
  * It is called from the driver's module-init function.
  */
 int __apr_driver_register(struct apr_driver *drv, struct module *owner)
 {
 	drv->driver.bus = &aprbus;
 	drv->driver.owner = owner;

 	return driver_register(&drv->driver);
 }
 EXPORT_SYMBOL_GPL(__apr_driver_register);

 /*
  * apr_driver_unregister() - Undo effect of apr_driver_register
  *
  * @drv: Client driver to be unregistered
  */
 void apr_driver_unregister(struct apr_driver *drv)
 {
 	driver_unregister(&drv->driver);
 }
 EXPORT_SYMBOL_GPL(apr_driver_unregister);

 static const struct of_device_id apr_of_match[] = {
 	{ .compatible = "qcom,apr"},
 	{ .compatible = "qcom,apr-v2"},
 	{}
 };
 MODULE_DEVICE_TABLE(of, apr_of_match);

 static struct rpmsg_driver apr_driver = {
 	.probe = apr_probe,
 	.remove = apr_remove,
 	.callback = apr_callback,
 	.drv = {
 		.name = "qcom,apr",
 		.of_match_table = apr_of_match,
 	},
 };

 static int __init apr_init(void)
 {
 	int ret;

 	ret = bus_register(&aprbus);
 	if (!ret)
 		ret = register_rpmsg_driver(&apr_driver);
 	else
 		bus_unregister(&aprbus);

 	return ret;
 }

 static void __exit apr_exit(void)
 {
 	bus_unregister(&aprbus);
 	unregister_rpmsg_driver(&apr_driver);
 }

 subsys_initcall(apr_init);
 module_exit(apr_exit);

 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("Qualcomm APR Bus");
	// SPDX-License-Identifier: GPL-2.0
	// Copyright (c) 2011-2017, The Linux Foundation. All rights reserved.
	// Copyright (c) 2018, Linaro Limited

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/device.h>
	#include <linux/spinlock.h>
	#include <linux/idr.h>
	#include <linux/slab.h>
	#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>

	struct apr {
	struct rpmsg_endpoint *ch;
	struct device *dev;
	spinlock_t svcs_lock;
	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;
	};

	struct apr_rx_buf {
	struct list_head node;
	int len;
	uint8_t buf[];
	};

	/**
	* apr_send_pkt() - Send a apr message from apr device
	*
	* @adev: Pointer to previously registered apr device.
	* @pkt: Pointer to apr packet to send
	*
	* Return: Will be an negative on packet size on success.
	*/
	int apr_send_pkt(struct apr_device adev, struct apr_pkt pkt)
	{
	struct apr *apr = dev_get_drvdata(adev->dev.parent);
	struct apr_hdr *hdr;
	unsigned long flags;
	int ret;

	spin_lock_irqsave(&adev->lock, flags);

	hdr = &pkt->hdr;
	hdr->src_domain = APR_DOMAIN_APPS;
	hdr->src_svc = adev->svc_id;
	hdr->dest_domain = adev->domain_id;
	hdr->dest_svc = adev->svc_id;

	ret = rpmsg_trysend(apr->ch, pkt, hdr->pkt_size);
	spin_unlock_irqrestore(&adev->lock, flags);

	return ret ? ret : hdr->pkt_size;
	}
	EXPORT_SYMBOL_GPL(apr_send_pkt);

	static void apr_dev_release(struct device *dev)
	{
	struct apr_device *adev = to_apr_device(dev);

	kfree(adev);
	}

	static int apr_callback(struct rpmsg_device rpdev, void buf,
	int len, void *priv, u32 addr)
	{
	struct apr *apr = dev_get_drvdata(&rpdev->dev);
	struct apr_rx_buf *abuf;
	unsigned long flags;

	if (len <= APR_HDR_SIZE) {
	dev_err(apr->dev, "APR: Improper apr pkt received:%p %d\n",
	buf, len);
	return -EINVAL;
	}

	abuf = kzalloc(sizeof(*abuf) + len, GFP_ATOMIC);
	if (!abuf)
	return -ENOMEM;

	abuf->len = len;
	memcpy(abuf->buf, buf, len);

	spin_lock_irqsave(&apr->rx_lock, flags);
	list_add_tail(&abuf->node, &apr->rx_list);
	spin_unlock_irqrestore(&apr->rx_lock, flags);

	queue_work(apr->rxwq, &apr->rx_work);

	return 0;
	}


	static int apr_do_rx_callback(struct apr apr, struct apr_rx_buf abuf)
	{
	uint16_t hdr_size, msg_type, ver, svc_id;
	struct apr_device *svc = NULL;
	struct apr_driver *adrv = NULL;
	struct apr_resp_pkt resp;
	struct apr_hdr *hdr;
	unsigned long flags;
	void *buf = abuf->buf;
	int len = abuf->len;

	hdr = buf;
	ver = APR_HDR_FIELD_VER(hdr->hdr_field);
	if (ver > APR_PKT_VER + 1)
	return -EINVAL;

	hdr_size = APR_HDR_FIELD_SIZE_BYTES(hdr->hdr_field);
	if (hdr_size < APR_HDR_SIZE) {
	dev_err(apr->dev, "APR: Wrong hdr size:%d\n", hdr_size);
	return -EINVAL;
	}

	if (hdr->pkt_size < APR_HDR_SIZE \|\| hdr->pkt_size != len) {
	dev_err(apr->dev, "APR: Wrong packet size\n");
	return -EINVAL;
	}

	msg_type = APR_HDR_FIELD_MT(hdr->hdr_field);
	if (msg_type >= APR_MSG_TYPE_MAX) {
	dev_err(apr->dev, "APR: Wrong message type: %d\n", msg_type);
	return -EINVAL;
	}

	if (hdr->src_domain >= APR_DOMAIN_MAX \|\|
	hdr->dest_domain >= APR_DOMAIN_MAX \|\|
	hdr->src_svc >= APR_SVC_MAX \|\|
	hdr->dest_svc >= APR_SVC_MAX) {
	dev_err(apr->dev, "APR: Wrong APR header\n");
	return -EINVAL;
	}

	svc_id = hdr->dest_svc;
	spin_lock_irqsave(&apr->svcs_lock, flags);
	svc = idr_find(&apr->svcs_idr, svc_id);
	if (svc && svc->dev.driver)
	adrv = to_apr_driver(svc->dev.driver);
	spin_unlock_irqrestore(&apr->svcs_lock, flags);

	if (!adrv) {
	dev_err(apr->dev, "APR: service is not registered\n");
	return -EINVAL;
	}

	resp.hdr = *hdr;
	resp.payload_size = hdr->pkt_size - hdr_size;

	/*
	* NOTE: hdr_size is not same as APR_HDR_SIZE as remote can include
	* optional headers in to apr_hdr which should be ignored
	*/
	if (resp.payload_size > 0)
	resp.payload = buf + hdr_size;

	adrv->callback(svc, &resp);

	return 0;
	}

	static void apr_rxwq(struct work_struct *work)
	{
	struct apr *apr = container_of(work, struct apr, rx_work);
	struct apr_rx_buf abuf, b;
	unsigned long flags;

	if (!list_empty(&apr->rx_list)) {
	list_for_each_entry_safe(abuf, b, &apr->rx_list, node) {
	apr_do_rx_callback(apr, abuf);
	spin_lock_irqsave(&apr->rx_lock, flags);
	list_del(&abuf->node);
	spin_unlock_irqrestore(&apr->rx_lock, flags);
	kfree(abuf);
	}
	}
	}

	static int apr_device_match(struct device dev, struct device_driver drv)
	{
	struct apr_device *adev = to_apr_device(dev);
	struct apr_driver *adrv = to_apr_driver(drv);
	const struct apr_device_id *id = adrv->id_table;

	/* Attempt an OF style match first */
	if (of_driver_match_device(dev, drv))
	return 1;

	if (!id)
	return 0;

	while (id->domain_id != 0 \|\| id->svc_id != 0) {
	if (id->domain_id == adev->domain_id &&
	id->svc_id == adev->svc_id)
	return 1;
	id++;
	}

	return 0;
	}

	static int apr_device_probe(struct device *dev)
	{
	struct apr_device *adev = to_apr_device(dev);
	struct apr_driver *adrv = to_apr_driver(dev->driver);

	return adrv->probe(adev);
	}

	static int apr_device_remove(struct device *dev)
	{
	struct apr_device *adev = to_apr_device(dev);
	struct apr_driver *adrv;
	struct apr *apr = dev_get_drvdata(adev->dev.parent);

	if (dev->driver) {
	adrv = to_apr_driver(dev->driver);
	if (adrv->remove)
	adrv->remove(adev);
	spin_lock(&apr->svcs_lock);
	idr_remove(&apr->svcs_idr, adev->svc_id);
	spin_unlock(&apr->svcs_lock);
	}

	return 0;
	}

	static int apr_uevent(struct device dev, struct kobj_uevent_env env)
	{
	struct apr_device *adev = to_apr_device(dev);
	int ret;

	ret = of_device_uevent_modalias(dev, env);
	if (ret != -ENODEV)
	return ret;

	return add_uevent_var(env, "MODALIAS=apr:%s", adev->name);
	}

	struct bus_type aprbus = {
	.name = "aprbus",
	.match = apr_device_match,
	.probe = apr_device_probe,
	.uevent = apr_uevent,
	.remove = apr_device_remove,
	};
	EXPORT_SYMBOL_GPL(aprbus);

	static int apr_add_device(struct device dev, struct device_node np,
	const struct apr_device_id *id)
	{
	struct apr *apr = dev_get_drvdata(dev);
	struct apr_device *adev = NULL;
	int ret;

	adev = kzalloc(sizeof(*adev), GFP_KERNEL);
	if (!adev)
	return -ENOMEM;

	spin_lock_init(&adev->lock);

	adev->svc_id = id->svc_id;
	adev->domain_id = id->domain_id;
	adev->version = id->svc_version;
	if (np)
	snprintf(adev->name, APR_NAME_SIZE, "%pOFn", np);
	else
	strscpy(adev->name, id->name, APR_NAME_SIZE);

	dev_set_name(&adev->dev, "aprsvc:%s:%x:%x", adev->name,
	id->domain_id, id->svc_id);

	adev->dev.bus = &aprbus;
	adev->dev.parent = dev;
	adev->dev.of_node = np;
	adev->dev.release = apr_dev_release;
	adev->dev.driver = NULL;

	spin_lock(&apr->svcs_lock);
	idr_alloc(&apr->svcs_idr, adev, id->svc_id,
	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);
	if (ret) {
	dev_err(dev, "device_register failed: %d\n", ret);
	put_device(&adev->dev);
	}

	return ret;
	}

	static int 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;
	struct pdr_service *pds;
	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) {
	dev_err(dev, "pdr service path missing: %d\n", ret);
	return ret;
	}

	pds = pdr_add_lookup(apr->pdr, service_name, service_path);
	if (IS_ERR(pds) && PTR_ERR(pds) != -EALREADY) {
	dev_err(dev, "pdr add lookup failed: %ld\n", PTR_ERR(pds));
	return PTR_ERR(pds);
	}
	}

	return 0;
	}

	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} };

	/*
	* This function is called with svc_path NULL during
	* apr_probe(), in which case we register any apr devices
	* without a qcom,protection-domain specified.
	*
	* Then as the protection domains becomes available
	* (if applicable) this function is again called, but with
	* svc_path representing the service becoming available. In
	* this case we register any apr devices with a matching
	* qcom,protection-domain.
	*/

	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;

	id.domain_id = apr->dest_domain_id;

	if (apr_add_device(dev, node, &id))
	dev_err(dev, "Failed to add apr %d svc\n", id.svc_id);
	}
	}

	static int apr_remove_device(struct device dev, void svc_path)
	{
	struct apr_device *adev = to_apr_device(dev);

	if (svc_path && adev->service_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(int state, char svc_path, void priv)
	{
	struct apr apr = (struct apr )priv;

	switch (state) {
	case SERVREG_SERVICE_STATE_UP:
	of_register_apr_devices(apr->dev, svc_path);
	break;
	case SERVREG_SERVICE_STATE_DOWN:
	device_for_each_child(apr->dev, svc_path, apr_remove_device);
	break;
	}
	}

	static int apr_probe(struct rpmsg_device *rpdev)
	{
	struct device *dev = &rpdev->dev;
	struct apr *apr;
	int ret;

	apr = devm_kzalloc(dev, sizeof(*apr), GFP_KERNEL);
	if (!apr)
	return -ENOMEM;

	ret = of_property_read_u32(dev->of_node, "qcom,apr-domain", &apr->dest_domain_id);
	if (ret) {
	dev_err(dev, "APR Domain ID not specified in DT\n");
	return ret;
	}

	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);

	apr->pdr = pdr_handle_alloc(apr_pd_status, apr);
	if (IS_ERR(apr->pdr)) {
	dev_err(dev, "Failed to init PDR handle\n");
	ret = PTR_ERR(apr->pdr);
	goto destroy_wq;
	}

	INIT_LIST_HEAD(&apr->rx_list);
	spin_lock_init(&apr->rx_lock);
	spin_lock_init(&apr->svcs_lock);
	idr_init(&apr->svcs_idr);

	ret = of_apr_add_pd_lookups(dev);
	if (ret)
	goto handle_release;

	of_register_apr_devices(dev, NULL);

	return 0;

	handle_release:
	pdr_handle_release(apr->pdr);
	destroy_wq:
	destroy_workqueue(apr->rxwq);
	return ret;
	}

	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);
	}

	/*
	* __apr_driver_register() - Client driver registration with aprbus
	*
	* @drv:Client driver to be associated with client-device.
	* @owner: owning module/driver
	*
	* This API will register the client driver with the aprbus
	* It is called from the driver's module-init function.
	*/
	int __apr_driver_register(struct apr_driver drv, struct module owner)
	{
	drv->driver.bus = &aprbus;
	drv->driver.owner = owner;

	return driver_register(&drv->driver);
	}
	EXPORT_SYMBOL_GPL(__apr_driver_register);

	/*
	* apr_driver_unregister() - Undo effect of apr_driver_register
	*
	* @drv: Client driver to be unregistered
	*/
	void apr_driver_unregister(struct apr_driver *drv)
	{
	driver_unregister(&drv->driver);
	}
	EXPORT_SYMBOL_GPL(apr_driver_unregister);

	static const struct of_device_id apr_of_match[] = {
	{ .compatible = "qcom,apr"},
	{ .compatible = "qcom,apr-v2"},
	{}
	};
	MODULE_DEVICE_TABLE(of, apr_of_match);

	static struct rpmsg_driver apr_driver = {
	.probe = apr_probe,
	.remove = apr_remove,
	.callback = apr_callback,
	.drv = {
	.name = "qcom,apr",
	.of_match_table = apr_of_match,
	},
	};

	static int __init apr_init(void)
	{
	int ret;

	ret = bus_register(&aprbus);
	if (!ret)
	ret = register_rpmsg_driver(&apr_driver);
	else
	bus_unregister(&aprbus);

	return ret;
	}

	static void __exit apr_exit(void)
	{
	bus_unregister(&aprbus);
	unregister_rpmsg_driver(&apr_driver);
	}

	subsys_initcall(apr_init);
	module_exit(apr_exit);

	MODULE_LICENSE("GPL v2");
	MODULE_DESCRIPTION("Qualcomm APR Bus");