soc: qcom: Add APR bus driver

This patch adds support to APR bus (Asynchronous Packet Router) driver.
APR driver is made as a bus driver so that the apr devices can added removed
more dynamically depending on the state of the services on the dsp.
APR is used for communication between application processor and QDSP to
use services on QDSP like Audio and others.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-and-tested-by: Rohit kumar <rohitkr@codeaurora.org>
Acked-by: Andy Gross <andy.gross@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

3 files changed, 388 insertions, 0 deletions

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 5c4535b545cc..d053f2634c67 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -108,4 +108,13 @@ config QCOM_WCNSS_CTRL
 	  Client driver for the WCNSS_CTRL SMD channel, used to download nv
 	  firmware to a newly booted WCNSS chip.
 
+config QCOM_APR
+	tristate "Qualcomm APR Bus (Asynchronous Packet Router)"
+	depends on ARCH_QCOM
+	depends on RPMSG
+	help
+          Enable APR IPC protocol support between
+          application processor and QDSP6. APR is
+          used by audio driver to configure QDSP6
+          ASM, ADM and AFE modules.
 endmenu
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index dcebf2814e6d..39de5dee55d9 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -12,3 +12,4 @@ obj-$(CONFIG_QCOM_SMEM_STATE) += smem_state.o
 obj-$(CONFIG_QCOM_SMP2P)	+= smp2p.o
 obj-$(CONFIG_QCOM_SMSM)	+= smsm.o
 obj-$(CONFIG_QCOM_WCNSS_CTRL) += wcnss_ctrl.o
+obj-$(CONFIG_QCOM_APR) += apr.o
diff --git a/drivers/soc/qcom/apr.c b/drivers/soc/qcom/apr.c
new file mode 100644
index 000000000000..97f3622da535
--- /dev/null
+++ b/drivers/soc/qcom/apr.c
@@ -0,0 +1,378 @@
+// 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/of_device.h>
+#include <linux/soc/qcom/apr.h>
+#include <linux/rpmsg.h>
+#include <linux/of.h>
+
+struct apr {
+	struct rpmsg_endpoint *ch;
+	struct device *dev;
+	spinlock_t svcs_lock;
+	struct idr svcs_idr;
+	int dest_domain_id;
+};
+
+/**
+ * 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);
+	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;
+
+	if (len <= APR_HDR_SIZE) {
+		dev_err(apr->dev, "APR: Improper apr pkt received:%p %d\n",
+			buf, len);
+		return -EINVAL;
+	}
+
+	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 paket size\n");
+		return -EINVAL;
+	}
+
+	msg_type = APR_HDR_FIELD_MT(hdr->hdr_field);
+	if (msg_type >= APR_MSG_TYPE_MAX && msg_type != APR_BASIC_RSP_RESULT) {
+		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 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)
+		strncpy(adev->name, np->name, APR_NAME_SIZE);
+	else
+		strncpy(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);
+
+	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 void of_register_apr_devices(struct device *dev)
+{
+	struct apr *apr = dev_get_drvdata(dev);
+	struct device_node *node;
+
+	for_each_child_of_node(dev->of_node, node) {
+		struct apr_device_id id = { {0} };
+
+		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_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, "reg", &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;
+	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);
+
+	return 0;
+}
+
+static void apr_remove(struct rpmsg_device *rpdev)
+{
+	device_for_each_child(&rpdev->dev, NULL, apr_remove_device);
+}
+
+/*
+ * __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");