On 1/15/20 2:27 AM, Arnaud Pouliquen wrote: > Return the rpmsg buffer MTU for sending message, so rpmsg users > can split a long message in several sub rpmsg buffers. > > Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@xxxxxx> Acked-by: Suman Anna <s-anna@xxxxxx> regards Suman > --- > V2[1] to V3 > - fix parameter description in rpmsg_device_ops struct > > [1]: https://lore.kernel.org/patchwork/patch/1124684/ > --- > drivers/rpmsg/rpmsg_core.c | 21 +++++++++++++++++++++ > drivers/rpmsg/rpmsg_internal.h | 2 ++ > drivers/rpmsg/virtio_rpmsg_bus.c | 10 ++++++++++ > include/linux/rpmsg.h | 10 ++++++++++ > 4 files changed, 43 insertions(+) > > diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c > index e330ec4dfc33..a6ef54c4779a 100644 > --- a/drivers/rpmsg/rpmsg_core.c > +++ b/drivers/rpmsg/rpmsg_core.c > @@ -283,6 +283,27 @@ 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 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 an 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 3fc83cd50e98..e6f88ee90ff6 100644 > --- a/drivers/rpmsg/rpmsg_internal.h > +++ b/drivers/rpmsg/rpmsg_internal.h > @@ -47,6 +47,7 @@ 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 > @@ -66,6 +67,7 @@ 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); > }; > > int rpmsg_register_device(struct rpmsg_device *rpdev); > diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c > index 376ebbf880d6..6e48fdf24555 100644 > --- a/drivers/rpmsg/virtio_rpmsg_bus.c > +++ b/drivers/rpmsg/virtio_rpmsg_bus.c > @@ -175,6 +175,7 @@ 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 const struct rpmsg_endpoint_ops virtio_endpoint_ops = { > .destroy_ept = virtio_rpmsg_destroy_ept, > @@ -184,6 +185,7 @@ 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, > }; > > /** > @@ -699,6 +701,14 @@ 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) > { > diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h > index 9fe156d1c018..88d7892ca93d 100644 > --- a/include/linux/rpmsg.h > +++ b/include/linux/rpmsg.h > @@ -135,6 +135,8 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst, > __poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp, > poll_table *wait); > > +ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept); > + > #else > > static inline int register_rpmsg_device(struct rpmsg_device *dev) > @@ -242,6 +244,14 @@ static inline __poll_t rpmsg_poll(struct rpmsg_endpoint *ept, > return 0; > } > > +static inline ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept) > +{ > + /* This shouldn't be possible */ > + WARN_ON(1); > + > + return -ENXIO; > +} > + > #endif /* IS_ENABLED(CONFIG_RPMSG) */ > > /* use a macro to avoid include chaining to get THIS_MODULE */ >
