// SPDX-License-Identifier: GPL-2.0 /* * Virtio-based remote processor messaging bus * * Copyright (C) 2011 Texas Instruments, Inc. * Copyright (C) 2011 Google, Inc. * * Ohad Ben-Cohen * Brian Swetland */ #define pr_fmt(fmt) "%s: " fmt, __func__ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "rpmsg_internal.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 * @num_bufs: total number of buffers for rx and tx * @buf_size: size of one rx or tx buffer * @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 * * 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; unsigned int num_bufs; unsigned int buf_size; 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; }; /* The feature bitmap for virtio rpmsg */ #define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */ /** * struct rpmsg_hdr - common header for all rpmsg messages * @src: source address * @dst: destination address * @reserved: reserved for future use * @len: length of payload (in bytes) * @flags: message flags * @data: @len bytes of message payload data * * Every message sent(/received) on the rpmsg bus begins with this header. */ struct rpmsg_hdr { __rpmsg32 src; __rpmsg32 dst; __rpmsg32 reserved; __rpmsg16 len; __rpmsg16 flags; u8 data[]; } __packed; /** * struct virtio_rpmsg_channel - rpmsg channel descriptor * @rpdev: the rpmsg channel device * @vrp: the virtio remote processor device this channel belongs to * * This structure stores the channel that links the rpmsg device to the virtio * remote processor device. */ struct virtio_rpmsg_channel { struct rpmsg_device rpdev; struct virtproc_info *vrp; }; #define to_virtio_rpmsg_channel(_rpdev) \ container_of(_rpdev, struct virtio_rpmsg_channel, rpdev) /* * We're allocating buffers of 512 bytes each for communications. The * number of buffers will be computed from the number of buffers supported * by the vring, upto a maximum of 512 buffers (256 in each direction). * * Each buffer will have 16 bytes for the msg header and 496 bytes for * the payload. * * This will utilize a maximum 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 MAX_RPMSG_NUM_BUFS (512) #define MAX_RPMSG_BUF_SIZE (512) /* * 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) static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept); static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len); static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst); static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst, void *data, int len); static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len); static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst); static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst, void *data, int len); static struct rpmsg_device *__rpmsg_create_channel(struct virtproc_info *vrp, struct rpmsg_channel_info *chinfo); static const struct rpmsg_endpoint_ops virtio_endpoint_ops = { .destroy_ept = virtio_rpmsg_destroy_ept, .send = virtio_rpmsg_send, .sendto = virtio_rpmsg_sendto, .send_offchannel = virtio_rpmsg_send_offchannel, .trysend = virtio_rpmsg_trysend, .trysendto = virtio_rpmsg_trysendto, .trysend_offchannel = virtio_rpmsg_trysend_offchannel, }; /** * rpmsg_sg_init - initialize scatterlist according to cpu address location * @sg: scatterlist to fill * @cpu_addr: virtual address of the buffer * @len: buffer length * * An internal function filling scatterlist according to virtual address * location (in vmalloc or in kernel). */ static void rpmsg_sg_init(struct scatterlist *sg, void *cpu_addr, unsigned int len) { if (is_vmalloc_addr(cpu_addr)) { sg_init_table(sg, 1); sg_set_page(sg, vmalloc_to_page(cpu_addr), len, offset_in_page(cpu_addr)); } else { WARN_ON(!virt_addr_valid(cpu_addr)); sg_init_one(sg, cpu_addr, len); } } /** * __ept_release() - deallocate an rpmsg endpoint * @kref: the ept's reference count * * This function deallocates an ept, and is invoked when its @kref refcount * drops to zero. * * Never invoke this function directly! */ static void __ept_release(struct kref *kref) { struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint, refcount); /* * At this point no one holds a reference to ept anymore, * so we can directly free it */ kfree(ept); } /* for more info, see below documentation of rpmsg_create_ept() */ static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp, struct rpmsg_device *rpdev, rpmsg_rx_cb_t cb, void *priv, u32 addr) { int id_min, id_max, id; struct rpmsg_endpoint *ept; struct device *dev = rpdev ? &rpdev->dev : &vrp->vdev->dev; ept = kzalloc(sizeof(*ept), GFP_KERNEL); if (!ept) return NULL; kref_init(&ept->refcount); mutex_init(&ept->cb_lock); ept->rpdev = rpdev; ept->cb = cb; ept->priv = priv; ept->ops = &virtio_endpoint_ops; /* do we need to allocate a local address ? */ if (addr == RPMSG_ADDR_ANY) { id_min = RPMSG_RESERVED_ADDRESSES; id_max = 0; } else { id_min = addr; id_max = addr + 1; } mutex_lock(&vrp->endpoints_lock); /* bind the endpoint to an rpmsg address (and allocate one if needed) */ id = idr_alloc(&vrp->endpoints, ept, id_min, id_max, GFP_KERNEL); if (id < 0) { dev_err(dev, "idr_alloc failed: %d\n", id); goto free_ept; } ept->addr = id; mutex_unlock(&vrp->endpoints_lock); return ept; free_ept: mutex_unlock(&vrp->endpoints_lock); kref_put(&ept->refcount, __ept_release); return NULL; } static struct rpmsg_device *virtio_rpmsg_create_channel(struct rpmsg_device *rpdev, struct rpmsg_channel_info *chinfo) { struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); struct virtproc_info *vrp = vch->vrp; return __rpmsg_create_channel(vrp, chinfo); } static int virtio_rpmsg_release_channel(struct rpmsg_device *rpdev, struct rpmsg_channel_info *chinfo) { struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); struct virtproc_info *vrp = vch->vrp; return rpmsg_unregister_device(&vrp->vdev->dev, chinfo); } static struct rpmsg_endpoint *virtio_rpmsg_create_ept(struct rpmsg_device *rpdev, rpmsg_rx_cb_t cb, void *priv, struct rpmsg_channel_info chinfo) { struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); return __rpmsg_create_ept(vch->vrp, rpdev, cb, priv, chinfo.src); } /** * __rpmsg_destroy_ept() - destroy an existing rpmsg endpoint * @vrp: virtproc which owns this ept * @ept: endpoing to destroy * * An internal function which destroy an ept without assuming it is * bound to an rpmsg channel. This is needed for handling the internal * name service endpoint, which isn't bound to an rpmsg channel. * See also __rpmsg_create_ept(). */ static void __rpmsg_destroy_ept(struct virtproc_info *vrp, struct rpmsg_endpoint *ept) { /* make sure new inbound messages can't find this ept anymore */ mutex_lock(&vrp->endpoints_lock); idr_remove(&vrp->endpoints, ept->addr); mutex_unlock(&vrp->endpoints_lock); /* make sure in-flight inbound messages won't invoke cb anymore */ mutex_lock(&ept->cb_lock); ept->cb = NULL; mutex_unlock(&ept->cb_lock); kref_put(&ept->refcount, __ept_release); } static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept) { struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(ept->rpdev); __rpmsg_destroy_ept(vch->vrp, ept); } static int virtio_rpmsg_announce_create(struct rpmsg_device *rpdev) { struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); struct virtproc_info *vrp = vch->vrp; struct device *dev = &rpdev->dev; int err = 0; /* need to tell remote processor's name service about this channel ? */ if (rpdev->announce && rpdev->ept && 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 = cpu_to_rpmsg32(rpdev, rpdev->ept->addr); nsm.flags = cpu_to_rpmsg32(rpdev, RPMSG_NS_CREATE); err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR); if (err) dev_err(dev, "failed to announce service %d\n", err); } return err; } static int virtio_rpmsg_announce_destroy(struct rpmsg_device *rpdev) { struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); struct virtproc_info *vrp = vch->vrp; struct device *dev = &rpdev->dev; int err = 0; /* tell remote processor's name service we're removing this channel */ if (rpdev->announce && rpdev->ept && 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 = cpu_to_rpmsg32(rpdev, rpdev->ept->addr); nsm.flags = cpu_to_rpmsg32(rpdev, RPMSG_NS_DESTROY); err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR); if (err) dev_err(dev, "failed to announce service %d\n", err); } return err; } static const struct rpmsg_device_ops virtio_rpmsg_ops = { .create_channel = virtio_rpmsg_create_channel, .release_channel = virtio_rpmsg_release_channel, .create_ept = virtio_rpmsg_create_ept, .announce_create = virtio_rpmsg_announce_create, .announce_destroy = virtio_rpmsg_announce_destroy, }; static void virtio_rpmsg_release_device(struct device *dev) { struct rpmsg_device *rpdev = to_rpmsg_device(dev); struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); kfree(vch); } /* * 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_device *__rpmsg_create_channel(struct virtproc_info *vrp, struct rpmsg_channel_info *chinfo) { struct virtio_rpmsg_channel *vch; struct rpmsg_device *rpdev; struct device *tmp, *dev = &vrp->vdev->dev; int ret; /* make sure a similar channel doesn't already exist */ tmp = rpmsg_find_device(dev, chinfo); 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; } vch = kzalloc(sizeof(*vch), GFP_KERNEL); if (!vch) return NULL; /* Link the channel to our vrp */ vch->vrp = vrp; /* Assign public information to the rpmsg_device */ rpdev = &vch->rpdev; rpdev->src = chinfo->src; rpdev->dst = chinfo->dst; rpdev->ops = &virtio_rpmsg_ops; rpdev->little_endian = virtio_is_little_endian(vrp->vdev); /* * rpmsg server channels has predefined local address (for now), * and their existence needs to be announced remotely */ rpdev->announce = rpdev->src != RPMSG_ADDR_ANY; strncpy(rpdev->id.name, chinfo->name, RPMSG_NAME_SIZE); rpdev->dev.parent = &vrp->vdev->dev; rpdev->dev.release = virtio_rpmsg_release_device; ret = rpmsg_register_device(rpdev); if (ret) return NULL; return rpdev; } /* 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 < vrp->num_bufs / 2) ret = vrp->sbufs + vrp->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. */ static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev, u32 src, u32 dst, void *data, int len, bool wait) { struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); struct virtproc_info *vrp = vch->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 > vrp->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 = cpu_to_rpmsg16(rpdev, len); msg->flags = 0; msg->src = cpu_to_rpmsg32(rpdev, src); msg->dst = cpu_to_rpmsg32(rpdev, 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", src, dst, len, msg->flags, msg->reserved); #if defined(CONFIG_DYNAMIC_DEBUG) dynamic_hex_dump("rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1, msg, sizeof(*msg) + len, true); #endif rpmsg_sg_init(&sg, msg, sizeof(*msg) + len); mutex_lock(&vrp->tx_lock); /* add message to the remote processor's virtqueue */ err = virtqueue_add_outbuf(vrp->svq, &sg, 1, msg, GFP_KERNEL); if (err) { /* * 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. */ dev_err(dev, "virtqueue_add_outbuf failed: %d\n", err); goto out; } /* tell the remote processor it has a pending message to read */ virtqueue_kick(vrp->svq); out: mutex_unlock(&vrp->tx_lock); return err; } static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len) { struct rpmsg_device *rpdev = ept->rpdev; u32 src = ept->addr, dst = rpdev->dst; return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true); } static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst) { struct rpmsg_device *rpdev = ept->rpdev; u32 src = ept->addr; return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true); } static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst, void *data, int len) { struct rpmsg_device *rpdev = ept->rpdev; return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true); } static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len) { struct rpmsg_device *rpdev = ept->rpdev; u32 src = ept->addr, dst = rpdev->dst; return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false); } static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst) { struct rpmsg_device *rpdev = ept->rpdev; u32 src = ept->addr; return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false); } static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst, void *data, int len) { struct rpmsg_device *rpdev = ept->rpdev; return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false); } static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev, struct rpmsg_hdr *msg, unsigned int len) { struct rpmsg_endpoint *ept; struct scatterlist sg; bool little_endian = virtio_is_little_endian(vrp->vdev); unsigned int msg_len = __rpmsg16_to_cpu(little_endian, msg->len); int err; dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n", __rpmsg32_to_cpu(little_endian, msg->src), __rpmsg32_to_cpu(little_endian, msg->dst), msg_len, __rpmsg16_to_cpu(little_endian, msg->flags), __rpmsg32_to_cpu(little_endian, msg->reserved)); #if defined(CONFIG_DYNAMIC_DEBUG) dynamic_hex_dump("rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1, msg, sizeof(*msg) + msg_len, true); #endif /* * We currently use fixed-sized buffers, so trivially sanitize * the reported payload length. */ if (len > vrp->buf_size || msg_len > (len - sizeof(struct rpmsg_hdr))) { dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg_len); return -EINVAL; } /* use the dst addr to fetch the callback of the appropriate user */ mutex_lock(&vrp->endpoints_lock); ept = idr_find(&vrp->endpoints, __rpmsg32_to_cpu(little_endian, msg->dst)); /* let's make sure no one deallocates ept while we use it */ if (ept) kref_get(&ept->refcount); mutex_unlock(&vrp->endpoints_lock); if (ept) { /* make sure ept->cb doesn't go away while we use it */ mutex_lock(&ept->cb_lock); if (ept->cb) ept->cb(ept->rpdev, msg->data, msg_len, ept->priv, __rpmsg32_to_cpu(little_endian, msg->src)); mutex_unlock(&ept->cb_lock); /* farewell, ept, we don't need you anymore */ kref_put(&ept->refcount, __ept_release); } else dev_warn(dev, "msg received with no recipient\n"); /* publish the real size of the buffer */ rpmsg_sg_init(&sg, msg, vrp->buf_size); /* add the buffer back to the remote processor's virtqueue */ err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, msg, GFP_KERNEL); if (err < 0) { dev_err(dev, "failed to add a virtqueue buffer: %d\n", err); return err; } return 0; } /* called when an rx buffer is used, and it's time to digest a message */ static void rpmsg_recv_done(struct virtqueue *rvq) { struct virtproc_info *vrp = rvq->vdev->priv; struct device *dev = &rvq->vdev->dev; struct rpmsg_hdr *msg; unsigned int len, msgs_received = 0; int err; msg = virtqueue_get_buf(rvq, &len); if (!msg) { dev_err(dev, "uhm, incoming signal, but no used buffer ?\n"); return; } while (msg) { err = rpmsg_recv_single(vrp, dev, msg, len); if (err) break; msgs_received++; msg = virtqueue_get_buf(rvq, &len); } dev_dbg(dev, "Received %u messages\n", msgs_received); /* tell the remote processor we added another available rx buffer */ if (msgs_received) 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); } /* * Called to expose to user a /dev/rpmsg_ctrlX interface allowing to * create endpoint-to-endpoint communication without associated RPMsg channel. * The endpoints are rattached to the ctrldev RPMsg device. */ static struct rpmsg_device *rpmsg_virtio_add_ctrl_dev(struct virtio_device *vdev) { struct virtproc_info *vrp = vdev->priv; struct virtio_rpmsg_channel *vch; struct rpmsg_device *rpdev_ctrl; int err = 0; vch = kzalloc(sizeof(*vch), GFP_KERNEL); if (!vch) return ERR_PTR(-ENOMEM); /* Link the channel to the vrp */ vch->vrp = vrp; /* Assign public information to the rpmsg_device */ rpdev_ctrl = &vch->rpdev; rpdev_ctrl->ops = &virtio_rpmsg_ops; rpdev_ctrl->dev.parent = &vrp->vdev->dev; rpdev_ctrl->dev.release = virtio_rpmsg_release_device; rpdev_ctrl->little_endian = virtio_is_little_endian(vrp->vdev); err = rpmsg_chrdev_register_device(rpdev_ctrl); if (err) { /* vch will be free in virtio_rpmsg_release_device() */ return ERR_PTR(err); } return rpdev_ctrl; } static void rpmsg_virtio_del_ctrl_dev(struct rpmsg_device *rpdev_ctrl) { if (!rpdev_ctrl) return; device_unregister(&rpdev_ctrl->dev); } static int rpmsg_probe(struct virtio_device *vdev) { vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done }; static const char * const names[] = { "input", "output" }; struct virtqueue *vqs[2]; struct virtproc_info *vrp; struct virtio_rpmsg_channel *vch = NULL; struct rpmsg_device *rpdev_ns, *rpdev_ctrl; void *bufs_va; int err = 0, i; size_t total_buf_space; bool notify; 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 = virtio_find_vqs(vdev, 2, vqs, vq_cbs, names, NULL); if (err) goto free_vrp; vrp->rvq = vqs[0]; vrp->svq = vqs[1]; /* we expect symmetric tx/rx vrings */ WARN_ON(virtqueue_get_vring_size(vrp->rvq) != virtqueue_get_vring_size(vrp->svq)); /* we need less buffers if vrings are small */ if (virtqueue_get_vring_size(vrp->rvq) < MAX_RPMSG_NUM_BUFS / 2) vrp->num_bufs = virtqueue_get_vring_size(vrp->rvq) * 2; else vrp->num_bufs = MAX_RPMSG_NUM_BUFS; vrp->buf_size = MAX_RPMSG_BUF_SIZE; total_buf_space = vrp->num_bufs * vrp->buf_size; /* allocate coherent memory for the buffers */ bufs_va = dma_alloc_coherent(vdev->dev.parent, total_buf_space, &vrp->bufs_dma, GFP_KERNEL); if (!bufs_va) { err = -ENOMEM; goto vqs_del; } dev_dbg(&vdev->dev, "buffers: va %pK, dma %pad\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 + total_buf_space / 2; /* set up the receive buffers */ for (i = 0; i < vrp->num_bufs / 2; i++) { struct scatterlist sg; void *cpu_addr = vrp->rbufs + i * vrp->buf_size; rpmsg_sg_init(&sg, cpu_addr, vrp->buf_size); err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, cpu_addr, GFP_KERNEL); WARN_ON(err); /* sanity check; this can't really happen */ } /* suppress "tx-complete" interrupts */ virtqueue_disable_cb(vrp->svq); vdev->priv = vrp; rpdev_ctrl = rpmsg_virtio_add_ctrl_dev(vdev); if (IS_ERR(rpdev_ctrl)) { err = PTR_ERR(rpdev_ctrl); goto free_coherent; } /* if supported by the remote processor, enable the name service */ if (virtio_has_feature(vdev, VIRTIO_RPMSG_F_NS)) { vch = kzalloc(sizeof(*vch), GFP_KERNEL); if (!vch) { err = -ENOMEM; goto free_ctrldev; } /* Link the channel to our vrp */ vch->vrp = vrp; /* Assign public information to the rpmsg_device */ rpdev_ns = &vch->rpdev; rpdev_ns->ops = &virtio_rpmsg_ops; rpdev_ns->little_endian = virtio_is_little_endian(vrp->vdev); rpdev_ns->dev.parent = &vrp->vdev->dev; rpdev_ns->dev.release = virtio_rpmsg_release_device; err = rpmsg_ns_register_device(rpdev_ns); if (err) /* vch will be free in virtio_rpmsg_release_device() */ goto free_ctrldev; } /* * Prepare to kick but don't notify yet - we can't do this before * device is ready. */ notify = virtqueue_kick_prepare(vrp->rvq); /* From this point on, we can notify and get callbacks. */ virtio_device_ready(vdev); /* tell the remote processor it can start sending messages */ /* * this might be concurrent with callbacks, but we are only * doing notify, not a full kick here, so that's ok. */ if (notify) virtqueue_notify(vrp->rvq); dev_info(&vdev->dev, "rpmsg host is online\n"); return 0; free_ctrldev: rpmsg_virtio_del_ctrl_dev(rpdev_ctrl); free_coherent: dma_free_coherent(vdev->dev.parent, 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 rpmsg_remove(struct virtio_device *vdev) { struct virtproc_info *vrp = vdev->priv; size_t total_buf_space = vrp->num_bufs * vrp->buf_size; 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_destroy(&vrp->endpoints); vdev->config->del_vqs(vrp->vdev); dma_free_coherent(vdev->dev.parent, 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 = rpmsg_remove, }; static int __init rpmsg_init(void) { int ret; ret = register_virtio_driver(&virtio_ipc_driver); if (ret) pr_err("failed to register virtio driver: %d\n", ret); return ret; } subsys_initcall(rpmsg_init); static void __exit rpmsg_fini(void) { unregister_virtio_driver(&virtio_ipc_driver); } module_exit(rpmsg_fini); MODULE_DEVICE_TABLE(virtio, id_table); MODULE_DESCRIPTION("Virtio-based remote processor messaging bus"); MODULE_LICENSE("GPL v2");