--- /dev/null
+/*
+ * remote processor messaging bus
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Ohad Ben-Cohen <ohad@wizery.com>
+ * Brian Swetland <swetland@google.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/rpmsg.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
+
+#include "rpmsg_internal.h"
+
+/**
+ * rpmsg_create_ept() - create a new rpmsg_endpoint
+ * @rpdev: rpmsg channel device
+ * @cb: rx callback handler
+ * @priv: private data for the driver's use
+ * @chinfo: channel_info with the local rpmsg address to bind with @cb
+ *
+ * Every rpmsg address in the system is bound to an rx callback (so when
+ * inbound messages arrive, they are dispatched by the rpmsg bus using the
+ * appropriate callback handler) by means of an rpmsg_endpoint struct.
+ *
+ * This function allows drivers to create such an endpoint, and by that,
+ * bind a callback, and possibly some private data too, to an rpmsg address
+ * (either one that is known in advance, or one that will be dynamically
+ * assigned for them).
+ *
+ * Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint
+ * is already created for them when they are probed by the rpmsg bus
+ * (using the rx callback provided when they registered to the rpmsg bus).
+ *
+ * So things should just work for simple drivers: they already have an
+ * endpoint, their rx callback is bound to their rpmsg address, and when
+ * relevant inbound messages arrive (i.e. messages which their dst address
+ * equals to the src address of their rpmsg channel), the driver's handler
+ * is invoked to process it.
+ *
+ * That said, more complicated drivers might do need to allocate
+ * additional rpmsg addresses, and bind them to different rx callbacks.
+ * To accomplish that, those drivers need to call this function.
+ *
+ * Drivers should provide their @rpdev channel (so the new endpoint would belong
+ * to the same remote processor their channel belongs to), an rx callback
+ * function, an optional private data (which is provided back when the
+ * rx callback is invoked), and an address they want to bind with the
+ * callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will
+ * dynamically assign them an available rpmsg address (drivers should have
+ * a very good reason why not to always use RPMSG_ADDR_ANY here).
+ *
+ * Returns a pointer to the endpoint on success, or NULL on error.
+ */
+struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
+ rpmsg_rx_cb_t cb, void *priv,
+ struct rpmsg_channel_info chinfo)
+{
+ return rpdev->ops->create_ept(rpdev, cb, priv, chinfo);
+}
+EXPORT_SYMBOL(rpmsg_create_ept);
+
+/**
+ * rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
+ * @ept: endpoing to destroy
+ *
+ * Should be used by drivers to destroy an rpmsg endpoint previously
+ * created with rpmsg_create_ept().
+ */
+void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
+{
+ ept->ops->destroy_ept(ept);
+}
+EXPORT_SYMBOL(rpmsg_destroy_ept);
+
+/**
+ * rpmsg_send() - send a message across to the remote processor
+ * @ept: the rpmsg endpoint
+ * @data: payload of message
+ * @len: length of payload
+ *
+ * This function sends @data of length @len on the @ept endpoint.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to, using @ept's address and its associated rpmsg
+ * device destination addresses.
+ * In case there are no TX buffers available, the function will block until
+ * one becomes available, or a timeout of 15 seconds elapses. When the latter
+ * happens, -ERESTARTSYS is returned.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+ return ept->ops->send(ept, data, len);
+}
+EXPORT_SYMBOL(rpmsg_send);
+
+/**
+ * rpmsg_sendto() - send a message across to the remote processor, specify dst
+ * @ept: the rpmsg endpoint
+ * @data: payload of message
+ * @len: length of payload
+ * @dst: destination address
+ *
+ * This function sends @data of length @len to the remote @dst address.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to, using @ept's address as source.
+ * In case there are no TX buffers available, the function will block until
+ * one becomes available, or a timeout of 15 seconds elapses. When the latter
+ * happens, -ERESTARTSYS is returned.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+ return ept->ops->sendto(ept, data, len, dst);
+}
+EXPORT_SYMBOL(rpmsg_sendto);
+
+/**
+ * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
+ * @ept: the rpmsg endpoint
+ * @src: source address
+ * @dst: destination address
+ * @data: payload of message
+ * @len: length of payload
+ *
+ * This function sends @data of length @len to the remote @dst address,
+ * and uses @src as the source address.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to.
+ * In case there are no TX buffers available, the function will block until
+ * one becomes available, or a timeout of 15 seconds elapses. When the latter
+ * happens, -ERESTARTSYS is returned.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+ void *data, int len)
+{
+ return ept->ops->send_offchannel(ept, src, dst, data, len);
+}
+EXPORT_SYMBOL(rpmsg_send_offchannel);
+
+/**
+ * rpmsg_send() - send a message across to the remote processor
+ * @ept: the rpmsg endpoint
+ * @data: payload of message
+ * @len: length of payload
+ *
+ * This function sends @data of length @len on the @ept endpoint.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to, using @ept's address as source and its associated
+ * rpdev's address as destination.
+ * In case there are no TX buffers available, the function will immediately
+ * return -ENOMEM without waiting until one becomes available.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+ return ept->ops->trysend(ept, data, len);
+}
+EXPORT_SYMBOL(rpmsg_trysend);
+
+/**
+ * rpmsg_sendto() - send a message across to the remote processor, specify dst
+ * @ept: the rpmsg endpoint
+ * @data: payload of message
+ * @len: length of payload
+ * @dst: destination address
+ *
+ * This function sends @data of length @len to the remote @dst address.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to, using @ept's address as source.
+ * In case there are no TX buffers available, the function will immediately
+ * return -ENOMEM without waiting until one becomes available.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+ return ept->ops->trysendto(ept, data, len, dst);
+}
+EXPORT_SYMBOL(rpmsg_trysendto);
+
+/**
+ * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
+ * @ept: the rpmsg endpoint
+ * @src: source address
+ * @dst: destination address
+ * @data: payload of message
+ * @len: length of payload
+ *
+ * This function sends @data of length @len to the remote @dst address,
+ * and uses @src as the source address.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to.
+ * In case there are no TX buffers available, the function will immediately
+ * return -ENOMEM without waiting until one becomes available.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+ void *data, int len)
+{
+ return ept->ops->trysend_offchannel(ept, src, dst, data, len);
+}
+EXPORT_SYMBOL(rpmsg_trysend_offchannel);
+
+/*
+ * match an rpmsg channel with a channel info struct.
+ * this is used to make sure we're not creating rpmsg devices for channels
+ * that already exist.
+ */
+static int rpmsg_device_match(struct device *dev, void *data)
+{
+ struct rpmsg_channel_info *chinfo = data;
+ struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+
+ if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src)
+ return 0;
+
+ if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst)
+ return 0;
+
+ if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE))
+ return 0;
+
+ /* found a match ! */
+ return 1;
+}
+
+struct device *rpmsg_find_device(struct device *parent,
+ struct rpmsg_channel_info *chinfo)
+{
+ return device_find_child(parent, chinfo, rpmsg_device_match);
+
+}
+EXPORT_SYMBOL(rpmsg_find_device);
+
+/* sysfs show configuration fields */
+#define rpmsg_show_attr(field, path, format_string) \
+static ssize_t \
+field##_show(struct device *dev, \
+ struct device_attribute *attr, char *buf) \
+{ \
+ struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
+ \
+ return sprintf(buf, format_string, rpdev->path); \
+}
+
+/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */
+rpmsg_show_attr(name, id.name, "%s\n");
+rpmsg_show_attr(src, src, "0x%x\n");
+rpmsg_show_attr(dst, dst, "0x%x\n");
+rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");
+
+static ssize_t modalias_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+
+ return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name);
+}
+
+static struct device_attribute rpmsg_dev_attrs[] = {
+ __ATTR_RO(name),
+ __ATTR_RO(modalias),
+ __ATTR_RO(dst),
+ __ATTR_RO(src),
+ __ATTR_RO(announce),
+ __ATTR_NULL
+};
+
+/* rpmsg devices and drivers are matched using the service name */
+static inline int rpmsg_id_match(const struct rpmsg_device *rpdev,
+ const struct rpmsg_device_id *id)
+{
+ return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
+}
+
+/* match rpmsg channel and rpmsg driver */
+static int rpmsg_dev_match(struct device *dev, struct device_driver *drv)
+{
+ struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+ struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
+ const struct rpmsg_device_id *ids = rpdrv->id_table;
+ unsigned int i;
+
+ if (ids)
+ for (i = 0; ids[i].name[0]; i++)
+ if (rpmsg_id_match(rpdev, &ids[i]))
+ return 1;
+
+ return of_driver_match_device(dev, drv);
+}
+
+static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+ struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+
+ return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT,
+ rpdev->id.name);
+}
+
+/*
+ * when an rpmsg driver is probed with a channel, we seamlessly create
+ * it an endpoint, binding its rx callback to a unique local rpmsg
+ * address.
+ *
+ * if we need to, we also announce about this channel to the remote
+ * processor (needed in case the driver is exposing an rpmsg service).
+ */
+static int rpmsg_dev_probe(struct device *dev)
+{
+ struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+ struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
+ struct rpmsg_channel_info chinfo = {};
+ struct rpmsg_endpoint *ept;
+ int err;
+
+ strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
+ chinfo.src = rpdev->src;
+ chinfo.dst = RPMSG_ADDR_ANY;
+
+ ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo);
+ if (!ept) {
+ dev_err(dev, "failed to create endpoint\n");
+ err = -ENOMEM;
+ goto out;
+ }
+
+ rpdev->ept = ept;
+ rpdev->src = ept->addr;
+
+ err = rpdrv->probe(rpdev);
+ if (err) {
+ dev_err(dev, "%s: failed: %d\n", __func__, err);
+ rpmsg_destroy_ept(ept);
+ goto out;
+ }
+
+ if (rpdev->ops->announce_create)
+ err = rpdev->ops->announce_create(rpdev);
+out:
+ return err;
+}
+
+static int rpmsg_dev_remove(struct device *dev)
+{
+ struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+ struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
+ int err = 0;
+
+ if (rpdev->ops->announce_destroy)
+ err = rpdev->ops->announce_destroy(rpdev);
+
+ rpdrv->remove(rpdev);
+
+ rpmsg_destroy_ept(rpdev->ept);
+
+ return err;
+}
+
+static struct bus_type rpmsg_bus = {
+ .name = "rpmsg",
+ .match = rpmsg_dev_match,
+ .dev_attrs = rpmsg_dev_attrs,
+ .uevent = rpmsg_uevent,
+ .probe = rpmsg_dev_probe,
+ .remove = rpmsg_dev_remove,
+};
+
+static void rpmsg_release_device(struct device *dev)
+{
+ struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+
+ kfree(rpdev);
+}
+
+int rpmsg_register_device(struct rpmsg_device *rpdev)
+{
+ struct device *dev = &rpdev->dev;
+ int ret;
+
+ dev_set_name(&rpdev->dev, "%s:%s",
+ dev_name(dev->parent), rpdev->id.name);
+
+ rpdev->dev.bus = &rpmsg_bus;
+ rpdev->dev.release = rpmsg_release_device;
+
+ ret = device_register(&rpdev->dev);
+ if (ret) {
+ dev_err(dev, "device_register failed: %d\n", ret);
+ put_device(&rpdev->dev);
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(rpmsg_register_device);
+
+/*
+ * find an existing channel using its name + address properties,
+ * and destroy it
+ */
+int rpmsg_unregister_device(struct device *parent,
+ struct rpmsg_channel_info *chinfo)
+{
+ struct device *dev;
+
+ dev = rpmsg_find_device(parent, chinfo);
+ if (!dev)
+ return -EINVAL;
+
+ device_unregister(dev);
+
+ put_device(dev);
+
+ return 0;
+}
+EXPORT_SYMBOL(rpmsg_unregister_device);
+
+/**
+ * __register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus
+ * @rpdrv: pointer to a struct rpmsg_driver
+ * @owner: owning module/driver
+ *
+ * Returns 0 on success, and an appropriate error value on failure.
+ */
+int __register_rpmsg_driver(struct rpmsg_driver *rpdrv, struct module *owner)
+{
+ rpdrv->drv.bus = &rpmsg_bus;
+ rpdrv->drv.owner = owner;
+ return driver_register(&rpdrv->drv);
+}
+EXPORT_SYMBOL(__register_rpmsg_driver);
+
+/**
+ * unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus
+ * @rpdrv: pointer to a struct rpmsg_driver
+ *
+ * Returns 0 on success, and an appropriate error value on failure.
+ */
+void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv)
+{
+ driver_unregister(&rpdrv->drv);
+}
+EXPORT_SYMBOL(unregister_rpmsg_driver);
+
+
+static int __init rpmsg_init(void)
+{
+ int ret;
+
+ ret = bus_register(&rpmsg_bus);
+ if (ret)
+ pr_err("failed to register rpmsg bus: %d\n", ret);
+
+ return ret;
+}
+postcore_initcall(rpmsg_init);
+
+static void __exit rpmsg_fini(void)
+{
+ bus_unregister(&rpmsg_bus);
+}
+module_exit(rpmsg_fini);
+
+MODULE_DESCRIPTION("remote processor messaging bus");
+MODULE_LICENSE("GPL v2");
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