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-rw-r--r--drivers/rpmsg/rpmsg_core.c21
-rw-r--r--drivers/rpmsg/rpmsg_internal.h2
-rw-r--r--drivers/rpmsg/virtio_rpmsg_bus.c10
3 files changed, 33 insertions, 0 deletions
diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
index 9151836190ce..d3eb60059ef1 100644
--- a/drivers/rpmsg/rpmsg_core.c
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -327,6 +327,27 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
}
EXPORT_SYMBOL(rpmsg_trysend_offchannel);
+/**
+ * rpmsg_get_mtu() - get maximum transmission buffer size for sending message.
+ * @ept: the rpmsg endpoint
+ *
+ * This function returns maximum buffer size available for a single outgoing message.
+ *
+ * Return: the maximum transmission size on success and an appropriate error
+ * value on failure.
+ */
+
+ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
+{
+ if (WARN_ON(!ept))
+ return -EINVAL;
+ if (!ept->ops->get_mtu)
+ return -ENOTSUPP;
+
+ return ept->ops->get_mtu(ept);
+}
+EXPORT_SYMBOL(rpmsg_get_mtu);
+
/*
* match a rpmsg channel with a channel info struct.
* this is used to make sure we're not creating rpmsg devices for channels
diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
index a76c344253bf..b1245d3ed7c6 100644
--- a/drivers/rpmsg/rpmsg_internal.h
+++ b/drivers/rpmsg/rpmsg_internal.h
@@ -53,6 +53,7 @@ struct rpmsg_device_ops {
* @trysendto: see @rpmsg_trysendto(), optional
* @trysend_offchannel: see @rpmsg_trysend_offchannel(), optional
* @poll: see @rpmsg_poll(), optional
+ * @get_mtu: see @rpmsg_get_mtu(), optional
*
* Indirection table for the operations that a rpmsg backend should implement.
* In addition to @destroy_ept, the backend must at least implement @send and
@@ -72,6 +73,7 @@ struct rpmsg_endpoint_ops {
void *data, int len);
__poll_t (*poll)(struct rpmsg_endpoint *ept, struct file *filp,
poll_table *wait);
+ ssize_t (*get_mtu)(struct rpmsg_endpoint *ept);
};
struct device *rpmsg_find_device(struct device *parent,
diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index 8e49a3bacfc7..05fd06fc67e9 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -149,6 +149,7 @@ 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 ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept);
static struct rpmsg_device *__rpmsg_create_channel(struct virtproc_info *vrp,
struct rpmsg_channel_info *chinfo);
@@ -160,6 +161,7 @@ static const struct rpmsg_endpoint_ops virtio_endpoint_ops = {
.trysend = virtio_rpmsg_trysend,
.trysendto = virtio_rpmsg_trysendto,
.trysend_offchannel = virtio_rpmsg_trysend_offchannel,
+ .get_mtu = virtio_rpmsg_get_mtu,
};
/**
@@ -696,6 +698,14 @@ static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
}
+static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept)
+{
+ struct rpmsg_device *rpdev = ept->rpdev;
+ struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
+
+ return vch->vrp->buf_size - sizeof(struct rpmsg_hdr);
+}
+
static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
struct rpmsg_hdr *msg, unsigned int len)
{