--- /dev/null
- err = virtqueue_add_buf_gfp(vrp->svq, &sg, 1, 0, msg, GFP_KERNEL);
+ /*
+ * Virtio-based 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/virtio.h>
+ #include <linux/virtio_ids.h>
+ #include <linux/virtio_config.h>
+ #include <linux/scatterlist.h>
+ #include <linux/dma-mapping.h>
+ #include <linux/slab.h>
+ #include <linux/idr.h>
+ #include <linux/jiffies.h>
+ #include <linux/sched.h>
+ #include <linux/wait.h>
+ #include <linux/rpmsg.h>
+ #include <linux/mutex.h>
+
+ /**
+ * struct virtproc_info - virtual remote processor state
+ * @vdev: the virtio device
+ * @rvq: rx virtqueue
+ * @svq: tx virtqueue
+ * @rbufs: kernel address of rx buffers
+ * @sbufs: kernel address of tx buffers
+ * @last_sbuf: index of last tx buffer used
+ * @bufs_dma: dma base addr of the buffers
+ * @tx_lock: protects svq, sbufs and sleepers, to allow concurrent senders.
+ * sending a message might require waking up a dozing remote
+ * processor, which involves sleeping, hence the mutex.
+ * @endpoints: idr of local endpoints, allows fast retrieval
+ * @endpoints_lock: lock of the endpoints set
+ * @sendq: wait queue of sending contexts waiting for a tx buffers
+ * @sleepers: number of senders that are waiting for a tx buffer
+ * @ns_ept: the bus's name service endpoint
+ *
+ * This structure stores the rpmsg state of a given virtio remote processor
+ * device (there might be several virtio proc devices for each physical
+ * remote processor).
+ */
+ struct virtproc_info {
+ struct virtio_device *vdev;
+ struct virtqueue *rvq, *svq;
+ void *rbufs, *sbufs;
+ int last_sbuf;
+ dma_addr_t bufs_dma;
+ struct mutex tx_lock;
+ struct idr endpoints;
+ struct mutex endpoints_lock;
+ wait_queue_head_t sendq;
+ atomic_t sleepers;
+ struct rpmsg_endpoint *ns_ept;
+ };
+
+ /**
+ * struct rpmsg_channel_info - internal channel info representation
+ * @name: name of service
+ * @src: local address
+ * @dst: destination address
+ */
+ struct rpmsg_channel_info {
+ char name[RPMSG_NAME_SIZE];
+ u32 src;
+ u32 dst;
+ };
+
+ #define to_rpmsg_channel(d) container_of(d, struct rpmsg_channel, dev)
+ #define to_rpmsg_driver(d) container_of(d, struct rpmsg_driver, drv)
+
+ /*
+ * We're allocating 512 buffers of 512 bytes for communications, and then
+ * using the first 256 buffers for RX, and the last 256 buffers for TX.
+ *
+ * Each buffer will have 16 bytes for the msg header and 496 bytes for
+ * the payload.
+ *
+ * This will require a total space of 256KB for the buffers.
+ *
+ * We might also want to add support for user-provided buffers in time.
+ * This will allow bigger buffer size flexibility, and can also be used
+ * to achieve zero-copy messaging.
+ *
+ * Note that these numbers are purely a decision of this driver - we
+ * can change this without changing anything in the firmware of the remote
+ * processor.
+ */
+ #define RPMSG_NUM_BUFS (512)
+ #define RPMSG_BUF_SIZE (512)
+ #define RPMSG_TOTAL_BUF_SPACE (RPMSG_NUM_BUFS * RPMSG_BUF_SIZE)
+
+ /*
+ * Local addresses are dynamically allocated on-demand.
+ * We do not dynamically assign addresses from the low 1024 range,
+ * in order to reserve that address range for predefined services.
+ */
+ #define RPMSG_RESERVED_ADDRESSES (1024)
+
+ /* Address 53 is reserved for advertising remote services */
+ #define RPMSG_NS_ADDR (53)
+
+ /* 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_channel *rpdev = to_rpmsg_channel(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");
+
+ /*
+ * Unique (and free running) index for rpmsg devices.
+ *
+ * Yeah, we're not recycling those numbers (yet?). will be easy
+ * to change if/when we want to.
+ */
+ static unsigned int rpmsg_dev_index;
+
+ static ssize_t modalias_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+ {
+ struct rpmsg_channel *rpdev = to_rpmsg_channel(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_channel *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_channel *rpdev = to_rpmsg_channel(dev);
+ struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
+ const struct rpmsg_device_id *ids = rpdrv->id_table;
+ unsigned int i;
+
+ for (i = 0; ids[i].name[0]; i++)
+ if (rpmsg_id_match(rpdev, &ids[i]))
+ return 1;
+
+ return 0;
+ }
+
+ static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
+ {
+ struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
+
+ return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT,
+ rpdev->id.name);
+ }
+
+ /* for more info, see below documentation of rpmsg_create_ept() */
+ static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
+ struct rpmsg_channel *rpdev, rpmsg_rx_cb_t cb,
+ void *priv, u32 addr)
+ {
+ int err, tmpaddr, request;
+ struct rpmsg_endpoint *ept;
+ struct device *dev = rpdev ? &rpdev->dev : &vrp->vdev->dev;
+
+ if (!idr_pre_get(&vrp->endpoints, GFP_KERNEL))
+ return NULL;
+
+ ept = kzalloc(sizeof(*ept), GFP_KERNEL);
+ if (!ept) {
+ dev_err(dev, "failed to kzalloc a new ept\n");
+ return NULL;
+ }
+
+ ept->rpdev = rpdev;
+ ept->cb = cb;
+ ept->priv = priv;
+
+ /* do we need to allocate a local address ? */
+ request = addr == RPMSG_ADDR_ANY ? RPMSG_RESERVED_ADDRESSES : addr;
+
+ mutex_lock(&vrp->endpoints_lock);
+
+ /* bind the endpoint to an rpmsg address (and allocate one if needed) */
+ err = idr_get_new_above(&vrp->endpoints, ept, request, &tmpaddr);
+ if (err) {
+ dev_err(dev, "idr_get_new_above failed: %d\n", err);
+ goto free_ept;
+ }
+
+ /* make sure the user's address request is fulfilled, if relevant */
+ if (addr != RPMSG_ADDR_ANY && tmpaddr != addr) {
+ dev_err(dev, "address 0x%x already in use\n", addr);
+ goto rem_idr;
+ }
+
+ ept->addr = tmpaddr;
+
+ mutex_unlock(&vrp->endpoints_lock);
+
+ return ept;
+
+ rem_idr:
+ idr_remove(&vrp->endpoints, request);
+ free_ept:
+ mutex_unlock(&vrp->endpoints_lock);
+ kfree(ept);
+ return NULL;
+ }
+
+ /**
+ * rpmsg_create_ept() - create a new rpmsg_endpoint
+ * @rpdev: rpmsg channel device
+ * @cb: rx callback handler
+ * @priv: private data for the driver's use
+ * @addr: 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_channel *rpdev,
+ rpmsg_rx_cb_t cb, void *priv, u32 addr)
+ {
+ return __rpmsg_create_ept(rpdev->vrp, rpdev, cb, priv, addr);
+ }
+ 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)
+ {
+ struct virtproc_info *vrp = ept->rpdev->vrp;
+
+ mutex_lock(&vrp->endpoints_lock);
+ idr_remove(&vrp->endpoints, ept->addr);
+ mutex_unlock(&vrp->endpoints_lock);
+
+ kfree(ept);
+ }
+ EXPORT_SYMBOL(rpmsg_destroy_ept);
+
+ /*
+ * 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_channel *rpdev = to_rpmsg_channel(dev);
+ struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
+ struct virtproc_info *vrp = rpdev->vrp;
+ struct rpmsg_endpoint *ept;
+ int err;
+
+ ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, rpdev->src);
+ 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;
+ }
+
+ /* need to tell remote processor's name service about this channel ? */
+ if (rpdev->announce &&
+ virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
+ struct rpmsg_ns_msg nsm;
+
+ strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
+ nsm.addr = rpdev->src;
+ nsm.flags = RPMSG_NS_CREATE;
+
+ err = rpmsg_sendto(rpdev, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
+ if (err)
+ dev_err(dev, "failed to announce service %d\n", err);
+ }
+
+ out:
+ return err;
+ }
+
+ static int rpmsg_dev_remove(struct device *dev)
+ {
+ struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
+ struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
+ struct virtproc_info *vrp = rpdev->vrp;
+ int err = 0;
+
+ /* tell remote processor's name service we're removing this channel */
+ if (rpdev->announce &&
+ virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
+ struct rpmsg_ns_msg nsm;
+
+ strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
+ nsm.addr = rpdev->src;
+ nsm.flags = RPMSG_NS_DESTROY;
+
+ err = rpmsg_sendto(rpdev, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
+ if (err)
+ dev_err(dev, "failed to announce service %d\n", err);
+ }
+
+ 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,
+ };
+
+ /**
+ * register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus
+ * @rpdrv: pointer to a struct rpmsg_driver
+ *
+ * Returns 0 on success, and an appropriate error value on failure.
+ */
+ int register_rpmsg_driver(struct rpmsg_driver *rpdrv)
+ {
+ rpdrv->drv.bus = &rpmsg_bus;
+ 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 void rpmsg_release_device(struct device *dev)
+ {
+ struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
+
+ kfree(rpdev);
+ }
+
+ /*
+ * 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_channel_match(struct device *dev, void *data)
+ {
+ struct rpmsg_channel_info *chinfo = data;
+ struct rpmsg_channel *rpdev = to_rpmsg_channel(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;
+ }
+
+ /*
+ * create an rpmsg channel using its name and address info.
+ * this function will be used to create both static and dynamic
+ * channels.
+ */
+ static struct rpmsg_channel *rpmsg_create_channel(struct virtproc_info *vrp,
+ struct rpmsg_channel_info *chinfo)
+ {
+ struct rpmsg_channel *rpdev;
+ struct device *tmp, *dev = &vrp->vdev->dev;
+ int ret;
+
+ /* make sure a similar channel doesn't already exist */
+ tmp = device_find_child(dev, chinfo, rpmsg_channel_match);
+ if (tmp) {
+ /* decrement the matched device's refcount back */
+ put_device(tmp);
+ dev_err(dev, "channel %s:%x:%x already exist\n",
+ chinfo->name, chinfo->src, chinfo->dst);
+ return NULL;
+ }
+
+ rpdev = kzalloc(sizeof(struct rpmsg_channel), GFP_KERNEL);
+ if (!rpdev) {
+ pr_err("kzalloc failed\n");
+ return NULL;
+ }
+
+ rpdev->vrp = vrp;
+ rpdev->src = chinfo->src;
+ rpdev->dst = chinfo->dst;
+
+ /*
+ * rpmsg server channels has predefined local address (for now),
+ * and their existence needs to be announced remotely
+ */
+ rpdev->announce = rpdev->src != RPMSG_ADDR_ANY ? true : false;
+
+ strncpy(rpdev->id.name, chinfo->name, RPMSG_NAME_SIZE);
+
+ /* very simple device indexing plumbing which is enough for now */
+ dev_set_name(&rpdev->dev, "rpmsg%d", rpmsg_dev_index++);
+
+ rpdev->dev.parent = &vrp->vdev->dev;
+ 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 NULL;
+ }
+
+ return rpdev;
+ }
+
+ /*
+ * find an existing channel using its name + address properties,
+ * and destroy it
+ */
+ static int rpmsg_destroy_channel(struct virtproc_info *vrp,
+ struct rpmsg_channel_info *chinfo)
+ {
+ struct virtio_device *vdev = vrp->vdev;
+ struct device *dev;
+
+ dev = device_find_child(&vdev->dev, chinfo, rpmsg_channel_match);
+ if (!dev)
+ return -EINVAL;
+
+ device_unregister(dev);
+
+ put_device(dev);
+
+ return 0;
+ }
+
+ /* super simple buffer "allocator" that is just enough for now */
+ static void *get_a_tx_buf(struct virtproc_info *vrp)
+ {
+ unsigned int len;
+ void *ret;
+
+ /* support multiple concurrent senders */
+ mutex_lock(&vrp->tx_lock);
+
+ /*
+ * either pick the next unused tx buffer
+ * (half of our buffers are used for sending messages)
+ */
+ if (vrp->last_sbuf < RPMSG_NUM_BUFS / 2)
+ ret = vrp->sbufs + RPMSG_BUF_SIZE * vrp->last_sbuf++;
+ /* or recycle a used one */
+ else
+ ret = virtqueue_get_buf(vrp->svq, &len);
+
+ mutex_unlock(&vrp->tx_lock);
+
+ return ret;
+ }
+
+ /**
+ * rpmsg_upref_sleepers() - enable "tx-complete" interrupts, if needed
+ * @vrp: virtual remote processor state
+ *
+ * This function is called before a sender is blocked, waiting for
+ * a tx buffer to become available.
+ *
+ * If we already have blocking senders, this function merely increases
+ * the "sleepers" reference count, and exits.
+ *
+ * Otherwise, if this is the first sender to block, we also enable
+ * virtio's tx callbacks, so we'd be immediately notified when a tx
+ * buffer is consumed (we rely on virtio's tx callback in order
+ * to wake up sleeping senders as soon as a tx buffer is used by the
+ * remote processor).
+ */
+ static void rpmsg_upref_sleepers(struct virtproc_info *vrp)
+ {
+ /* support multiple concurrent senders */
+ mutex_lock(&vrp->tx_lock);
+
+ /* are we the first sleeping context waiting for tx buffers ? */
+ if (atomic_inc_return(&vrp->sleepers) == 1)
+ /* enable "tx-complete" interrupts before dozing off */
+ virtqueue_enable_cb(vrp->svq);
+
+ mutex_unlock(&vrp->tx_lock);
+ }
+
+ /**
+ * rpmsg_downref_sleepers() - disable "tx-complete" interrupts, if needed
+ * @vrp: virtual remote processor state
+ *
+ * This function is called after a sender, that waited for a tx buffer
+ * to become available, is unblocked.
+ *
+ * If we still have blocking senders, this function merely decreases
+ * the "sleepers" reference count, and exits.
+ *
+ * Otherwise, if there are no more blocking senders, we also disable
+ * virtio's tx callbacks, to avoid the overhead incurred with handling
+ * those (now redundant) interrupts.
+ */
+ static void rpmsg_downref_sleepers(struct virtproc_info *vrp)
+ {
+ /* support multiple concurrent senders */
+ mutex_lock(&vrp->tx_lock);
+
+ /* are we the last sleeping context waiting for tx buffers ? */
+ if (atomic_dec_and_test(&vrp->sleepers))
+ /* disable "tx-complete" interrupts */
+ virtqueue_disable_cb(vrp->svq);
+
+ mutex_unlock(&vrp->tx_lock);
+ }
+
+ /**
+ * rpmsg_send_offchannel_raw() - send a message across to the remote processor
+ * @rpdev: the rpmsg channel
+ * @src: source address
+ * @dst: destination address
+ * @data: payload of message
+ * @len: length of payload
+ * @wait: indicates whether caller should block in case no TX buffers available
+ *
+ * This function is the base implementation for all of the rpmsg sending API.
+ *
+ * It will send @data of length @len to @dst, and say it's from @src. The
+ * message will be sent to the remote processor which the @rpdev channel
+ * belongs to.
+ *
+ * The message is sent using one of the TX buffers that are available for
+ * communication with this remote processor.
+ *
+ * If @wait is true, the caller will be blocked until either a TX buffer is
+ * available, or 15 seconds elapses (we don't want callers to
+ * sleep indefinitely due to misbehaving remote processors), and in that
+ * case -ERESTARTSYS is returned. The number '15' itself was picked
+ * arbitrarily; there's little point in asking drivers to provide a timeout
+ * value themselves.
+ *
+ * Otherwise, if @wait is false, and there are no TX buffers available,
+ * the function will immediately fail, and -ENOMEM will be returned.
+ *
+ * Normally drivers shouldn't use this function directly; instead, drivers
+ * should use the appropriate rpmsg_{try}send{to, _offchannel} API
+ * (see include/linux/rpmsg.h).
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+ int rpmsg_send_offchannel_raw(struct rpmsg_channel *rpdev, u32 src, u32 dst,
+ void *data, int len, bool wait)
+ {
+ struct virtproc_info *vrp = rpdev->vrp;
+ struct device *dev = &rpdev->dev;
+ struct scatterlist sg;
+ struct rpmsg_hdr *msg;
+ int err;
+
+ /* bcasting isn't allowed */
+ if (src == RPMSG_ADDR_ANY || dst == RPMSG_ADDR_ANY) {
+ dev_err(dev, "invalid addr (src 0x%x, dst 0x%x)\n", src, dst);
+ return -EINVAL;
+ }
+
+ /*
+ * We currently use fixed-sized buffers, and therefore the payload
+ * length is limited.
+ *
+ * One of the possible improvements here is either to support
+ * user-provided buffers (and then we can also support zero-copy
+ * messaging), or to improve the buffer allocator, to support
+ * variable-length buffer sizes.
+ */
+ if (len > RPMSG_BUF_SIZE - sizeof(struct rpmsg_hdr)) {
+ dev_err(dev, "message is too big (%d)\n", len);
+ return -EMSGSIZE;
+ }
+
+ /* grab a buffer */
+ msg = get_a_tx_buf(vrp);
+ if (!msg && !wait)
+ return -ENOMEM;
+
+ /* no free buffer ? wait for one (but bail after 15 seconds) */
+ while (!msg) {
+ /* enable "tx-complete" interrupts, if not already enabled */
+ rpmsg_upref_sleepers(vrp);
+
+ /*
+ * sleep until a free buffer is available or 15 secs elapse.
+ * the timeout period is not configurable because there's
+ * little point in asking drivers to specify that.
+ * if later this happens to be required, it'd be easy to add.
+ */
+ err = wait_event_interruptible_timeout(vrp->sendq,
+ (msg = get_a_tx_buf(vrp)),
+ msecs_to_jiffies(15000));
+
+ /* disable "tx-complete" interrupts if we're the last sleeper */
+ rpmsg_downref_sleepers(vrp);
+
+ /* timeout ? */
+ if (!err) {
+ dev_err(dev, "timeout waiting for a tx buffer\n");
+ return -ERESTARTSYS;
+ }
+ }
+
+ msg->len = len;
+ msg->flags = 0;
+ msg->src = src;
+ msg->dst = dst;
+ msg->reserved = 0;
+ memcpy(msg->data, data, len);
+
+ dev_dbg(dev, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n",
+ msg->src, msg->dst, msg->len,
+ msg->flags, msg->reserved);
+ print_hex_dump(KERN_DEBUG, "rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1,
+ msg, sizeof(*msg) + msg->len, true);
+
+ sg_init_one(&sg, msg, sizeof(*msg) + len);
+
+ mutex_lock(&vrp->tx_lock);
+
+ /* add message to the remote processor's virtqueue */
- dev_err(dev, "virtqueue_add_buf_gfp failed: %d\n", err);
++ err = virtqueue_add_buf(vrp->svq, &sg, 1, 0, msg, GFP_KERNEL);
+ if (err < 0) {
+ /*
+ * need to reclaim the buffer here, otherwise it's lost
+ * (memory won't leak, but rpmsg won't use it again for TX).
+ * this will wait for a buffer management overhaul.
+ */
- err = virtqueue_add_buf_gfp(vrp->rvq, &sg, 0, 1, msg, GFP_KERNEL);
++ dev_err(dev, "virtqueue_add_buf failed: %d\n", err);
+ goto out;
+ }
+
+ /* tell the remote processor it has a pending message to read */
+ virtqueue_kick(vrp->svq);
+
+ err = 0;
+ out:
+ mutex_unlock(&vrp->tx_lock);
+ return err;
+ }
+ EXPORT_SYMBOL(rpmsg_send_offchannel_raw);
+
+ /* called when an rx buffer is used, and it's time to digest a message */
+ static void rpmsg_recv_done(struct virtqueue *rvq)
+ {
+ struct rpmsg_hdr *msg;
+ unsigned int len;
+ struct rpmsg_endpoint *ept;
+ struct scatterlist sg;
+ struct virtproc_info *vrp = rvq->vdev->priv;
+ struct device *dev = &rvq->vdev->dev;
+ int err;
+
+ msg = virtqueue_get_buf(rvq, &len);
+ if (!msg) {
+ dev_err(dev, "uhm, incoming signal, but no used buffer ?\n");
+ return;
+ }
+
+ dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n",
+ msg->src, msg->dst, msg->len,
+ msg->flags, msg->reserved);
+ print_hex_dump(KERN_DEBUG, "rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1,
+ msg, sizeof(*msg) + msg->len, true);
+
+ /* use the dst addr to fetch the callback of the appropriate user */
+ mutex_lock(&vrp->endpoints_lock);
+ ept = idr_find(&vrp->endpoints, msg->dst);
+ mutex_unlock(&vrp->endpoints_lock);
+
+ if (ept && ept->cb)
+ ept->cb(ept->rpdev, msg->data, msg->len, ept->priv, msg->src);
+ else
+ dev_warn(dev, "msg received with no recepient\n");
+
+ sg_init_one(&sg, msg, sizeof(*msg) + len);
+
+ /* add the buffer back to the remote processor's virtqueue */
- err = virtqueue_add_buf_gfp(vrp->rvq, &sg, 0, 1, cpu_addr,
++ err = virtqueue_add_buf(vrp->rvq, &sg, 0, 1, msg, GFP_KERNEL);
+ if (err < 0) {
+ dev_err(dev, "failed to add a virtqueue buffer: %d\n", err);
+ return;
+ }
+
+ /* tell the remote processor we added another available rx buffer */
+ virtqueue_kick(vrp->rvq);
+ }
+
+ /*
+ * This is invoked whenever the remote processor completed processing
+ * a TX msg we just sent it, and the buffer is put back to the used ring.
+ *
+ * Normally, though, we suppress this "tx complete" interrupt in order to
+ * avoid the incurred overhead.
+ */
+ static void rpmsg_xmit_done(struct virtqueue *svq)
+ {
+ struct virtproc_info *vrp = svq->vdev->priv;
+
+ dev_dbg(&svq->vdev->dev, "%s\n", __func__);
+
+ /* wake up potential senders that are waiting for a tx buffer */
+ wake_up_interruptible(&vrp->sendq);
+ }
+
+ /* invoked when a name service announcement arrives */
+ static void rpmsg_ns_cb(struct rpmsg_channel *rpdev, void *data, int len,
+ void *priv, u32 src)
+ {
+ struct rpmsg_ns_msg *msg = data;
+ struct rpmsg_channel *newch;
+ struct rpmsg_channel_info chinfo;
+ struct virtproc_info *vrp = priv;
+ struct device *dev = &vrp->vdev->dev;
+ int ret;
+
+ print_hex_dump(KERN_DEBUG, "NS announcement: ",
+ DUMP_PREFIX_NONE, 16, 1,
+ data, len, true);
+
+ if (len != sizeof(*msg)) {
+ dev_err(dev, "malformed ns msg (%d)\n", len);
+ return;
+ }
+
+ /*
+ * the name service ept does _not_ belong to a real rpmsg channel,
+ * and is handled by the rpmsg bus itself.
+ * for sanity reasons, make sure a valid rpdev has _not_ sneaked
+ * in somehow.
+ */
+ if (rpdev) {
+ dev_err(dev, "anomaly: ns ept has an rpdev handle\n");
+ return;
+ }
+
+ /* don't trust the remote processor for null terminating the name */
+ msg->name[RPMSG_NAME_SIZE - 1] = '\0';
+
+ dev_info(dev, "%sing channel %s addr 0x%x\n",
+ msg->flags & RPMSG_NS_DESTROY ? "destroy" : "creat",
+ msg->name, msg->addr);
+
+ strncpy(chinfo.name, msg->name, sizeof(chinfo.name));
+ chinfo.src = RPMSG_ADDR_ANY;
+ chinfo.dst = msg->addr;
+
+ if (msg->flags & RPMSG_NS_DESTROY) {
+ ret = rpmsg_destroy_channel(vrp, &chinfo);
+ if (ret)
+ dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret);
+ } else {
+ newch = rpmsg_create_channel(vrp, &chinfo);
+ if (!newch)
+ dev_err(dev, "rpmsg_create_channel failed\n");
+ }
+ }
+
+ static int rpmsg_probe(struct virtio_device *vdev)
+ {
+ vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done };
+ const char *names[] = { "input", "output" };
+ struct virtqueue *vqs[2];
+ struct virtproc_info *vrp;
+ void *bufs_va;
+ int err = 0, i;
+
+ vrp = kzalloc(sizeof(*vrp), GFP_KERNEL);
+ if (!vrp)
+ return -ENOMEM;
+
+ vrp->vdev = vdev;
+
+ idr_init(&vrp->endpoints);
+ mutex_init(&vrp->endpoints_lock);
+ mutex_init(&vrp->tx_lock);
+ init_waitqueue_head(&vrp->sendq);
+
+ /* We expect two virtqueues, rx and tx (and in this order) */
+ err = vdev->config->find_vqs(vdev, 2, vqs, vq_cbs, names);
+ if (err)
+ goto free_vrp;
+
+ vrp->rvq = vqs[0];
+ vrp->svq = vqs[1];
+
+ /* allocate coherent memory for the buffers */
+ bufs_va = dma_alloc_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE,
+ &vrp->bufs_dma, GFP_KERNEL);
+ if (!bufs_va)
+ goto vqs_del;
+
+ dev_dbg(&vdev->dev, "buffers: va %p, dma 0x%x\n", bufs_va,
+ vrp->bufs_dma);
+
+ /* half of the buffers is dedicated for RX */
+ vrp->rbufs = bufs_va;
+
+ /* and half is dedicated for TX */
+ vrp->sbufs = bufs_va + RPMSG_TOTAL_BUF_SPACE / 2;
+
+ /* set up the receive buffers */
+ for (i = 0; i < RPMSG_NUM_BUFS / 2; i++) {
+ struct scatterlist sg;
+ void *cpu_addr = vrp->rbufs + i * RPMSG_BUF_SIZE;
+
+ sg_init_one(&sg, cpu_addr, RPMSG_BUF_SIZE);
+
++ err = virtqueue_add_buf(vrp->rvq, &sg, 0, 1, cpu_addr,
+ GFP_KERNEL);
+ WARN_ON(err < 0); /* sanity check; this can't really happen */
+ }
+
+ /* suppress "tx-complete" interrupts */
+ virtqueue_disable_cb(vrp->svq);
+
+ vdev->priv = vrp;
+
+ /* if supported by the remote processor, enable the name service */
+ if (virtio_has_feature(vdev, VIRTIO_RPMSG_F_NS)) {
+ /* a dedicated endpoint handles the name service msgs */
+ vrp->ns_ept = __rpmsg_create_ept(vrp, NULL, rpmsg_ns_cb,
+ vrp, RPMSG_NS_ADDR);
+ if (!vrp->ns_ept) {
+ dev_err(&vdev->dev, "failed to create the ns ept\n");
+ err = -ENOMEM;
+ goto free_coherent;
+ }
+ }
+
+ /* tell the remote processor it can start sending messages */
+ virtqueue_kick(vrp->rvq);
+
+ dev_info(&vdev->dev, "rpmsg host is online\n");
+
+ return 0;
+
+ free_coherent:
+ dma_free_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE, bufs_va,
+ vrp->bufs_dma);
+ vqs_del:
+ vdev->config->del_vqs(vrp->vdev);
+ free_vrp:
+ kfree(vrp);
+ return err;
+ }
+
+ static int rpmsg_remove_device(struct device *dev, void *data)
+ {
+ device_unregister(dev);
+
+ return 0;
+ }
+
+ static void __devexit rpmsg_remove(struct virtio_device *vdev)
+ {
+ struct virtproc_info *vrp = vdev->priv;
+ int ret;
+
+ vdev->config->reset(vdev);
+
+ ret = device_for_each_child(&vdev->dev, NULL, rpmsg_remove_device);
+ if (ret)
+ dev_warn(&vdev->dev, "can't remove rpmsg device: %d\n", ret);
+
+ idr_remove_all(&vrp->endpoints);
+ idr_destroy(&vrp->endpoints);
+
+ vdev->config->del_vqs(vrp->vdev);
+
+ dma_free_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE,
+ vrp->rbufs, vrp->bufs_dma);
+
+ kfree(vrp);
+ }
+
+ static struct virtio_device_id id_table[] = {
+ { VIRTIO_ID_RPMSG, VIRTIO_DEV_ANY_ID },
+ { 0 },
+ };
+
+ static unsigned int features[] = {
+ VIRTIO_RPMSG_F_NS,
+ };
+
+ static struct virtio_driver virtio_ipc_driver = {
+ .feature_table = features,
+ .feature_table_size = ARRAY_SIZE(features),
+ .driver.name = KBUILD_MODNAME,
+ .driver.owner = THIS_MODULE,
+ .id_table = id_table,
+ .probe = rpmsg_probe,
+ .remove = __devexit_p(rpmsg_remove),
+ };
+
+ 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;
+ }
+
+ ret = register_virtio_driver(&virtio_ipc_driver);
+ if (ret) {
+ pr_err("failed to register virtio driver: %d\n", ret);
+ bus_unregister(&rpmsg_bus);
+ }
+
+ return ret;
+ }
+ module_init(rpmsg_init);
+
+ static void __exit rpmsg_fini(void)
+ {
+ unregister_virtio_driver(&virtio_ipc_driver);
+ bus_unregister(&rpmsg_bus);
+ }
+ module_exit(rpmsg_fini);
+
+ MODULE_DEVICE_TABLE(virtio, id_table);
+ MODULE_DESCRIPTION("Virtio-based remote processor messaging bus");
+ MODULE_LICENSE("GPL v2");
projects / karo-tx-linux.git / commitdiff