Hi Arnaud, On 8/28/19 10:19 AM, Arnaud Pouliquen wrote: > Return the rpmsg buffer size for sending message, so rpmsg users > can split a long message in several sub rpmsg buffers.
Thanks for the patch, I also have a need for the same to be able to compute permissible payload size. Minor comments below. > > Signed-off-by: Arnaud Pouliquen <[email protected]> > --- > V4 to V5 : > - rename rpmsg_get_buf_payload_size to rpmsg_get_mtu > > 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 8122807db380..daca2e24fc71 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_buf_mtu) How about calling the ops just get_mtu or rename the function to follow the ops name, like all the others. > + return -ENXIO; Perhaps ENOTSUPP or EOPNOTSUPP. > + > + return ept->ops->get_buf_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 0d791c30b7ea..645c402569ac 100644 > --- a/drivers/rpmsg/rpmsg_internal.h > +++ b/drivers/rpmsg/rpmsg_internal.h > @@ -46,6 +46,7 @@ struct rpmsg_device_ops { > * @trysend: see @rpmsg_trysend(), required > * @trysendto: see @rpmsg_trysendto(), optional > * @trysend_offchannel: see @rpmsg_trysend_offchannel(), optional > + * @get_buf_payload_size: see @rpmsg_get_buf_payload_size(), optional Missed updating the kerneldoc to the new name. > * > * Indirection table for the operations that a rpmsg backend should > implement. > * In addition to @destroy_ept, the backend must at least implement @send and > @@ -65,6 +66,7 @@ struct rpmsg_endpoint_ops { > void *data, int len); > __poll_t (*poll)(struct rpmsg_endpoint *ept, struct file *filp, > poll_table *wait); > + ssize_t (*get_buf_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 e757f0038a1c..f80b1ad23e7e 100644 > --- a/drivers/rpmsg/virtio_rpmsg_bus.c > +++ b/drivers/rpmsg/virtio_rpmsg_bus.c > @@ -178,6 +178,7 @@ 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_get_buf_mtu(struct rpmsg_endpoint *ept); Minor nit, virtio_rpmsg_ prefix similar to all the other ops. regards Suman > > static const struct rpmsg_endpoint_ops virtio_endpoint_ops = { > .destroy_ept = virtio_rpmsg_destroy_ept, > @@ -187,6 +188,7 @@ static const struct rpmsg_endpoint_ops > virtio_endpoint_ops = { > .trysend = virtio_rpmsg_trysend, > .trysendto = virtio_rpmsg_trysendto, > .trysend_offchannel = virtio_rpmsg_trysend_offchannel, > + .get_buf_mtu = virtio_get_buf_mtu, > }; > > /** > @@ -702,6 +704,14 @@ 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_get_buf_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..9d638bf2bdce 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 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 */ >
