Current design uses fixed (512 bytes) rpmsg buffer size in both rx and tx directions. This design is not suitable if the payload is larger than 512 bytes or the payload is very small and doesn't need that much memory. Instead introduce new virtio feature to retrieve rpmsg tx buf size and rx buf size from the virtio config space in the resource table.
Changes in v3: - new patch [1/4] that renames variables with clear names. - %s/rbufs/rx_bufs/ - %s/sbufs/tx_bufs/ - %s/last_sbuf/last_tx_buf/ - add num_rx_buf and num_tx_buf in the documentation - change version field from u16 to u8 - introduce size field in the rpmsg_virtio_config structure - check version field is set to any non-zero value. - check size field is not 0. - Remove field for private config, as not needed for now. - add documentation of rpmsg_virtio_config structure - Check for error when retrieving MTU size in the sample driver - %s/mtu/MTU/ Changes in v2: - Change author - fix commit message with better explanation - %s/sbuf/tx_buf - %s/rbuf/rx_buf - %s/num_rbuf/num_rx_buf/ - %s/num_sbuf/num_tx_buf/ - %s/sbuf_size/tx_buf_size/ - %s/rbuf_size/rx_buf_size/ - fix typo - do not use ALIGN on buf size, rely on allocator - make err msg more explicit, %s/vdev config:/bad vdev config/ - fix license and add AMD copyrights in the header virtio_rpmsg.h - Assign bit 1 to VIRTIO_RPMSG_F_BUFSZ feature - use __virtio32 over __u32 - add version field to virtio rpmsg config structure - Introduce new patch to print rpmsg mtu size in the sample rpmsg driver - move linux/virtio_rpmsg.h to linux/rpmsg/virtio_rpmsg.h Original seris: https://lore.kernel.org/all/[email protected]/ Following modificaitons are done to the original series in v1: - Separate dma allocation is not done for tx and rx buffers. Instead allocated chunk of memory is split between tx and rx buffers. - If vdev doesn't support VIRTIO_RPMSG_F_BUFSZ feature then use the default size of 512 bytes for buffers - Change MAX_RPMSG_BUF_SIZE to DEFAULT_RPMSG_BUF_SIZE - move virtio_rpmsg.h from uapi to linux dir - RPMsg buffer size must be set to hold rpmsg header at minimum in the vdev config space of the firmware. - align total buf size to page size when allocating and deallocating memory Corresponding OpenAMP project PR: - open-amp library: https://github.com/OpenAMP/open-amp/pull/684 - openamp-system-reference demo: https://github.com/OpenAMP/openamp-system-reference/pull/106 Tanmay Shah (4): rpmsg: virtio_rpmsg_bus: rename rbufs and sbufs rpmsg: virtio_rpmsg_bus: allow different size of tx and rx bufs rpmsg: virtio_rpmsg_bus: get buffer size from config space samples: rpmsg: add MTU size info drivers/rpmsg/virtio_rpmsg_bus.c | 148 +++++++++++++++++++--------- include/linux/rpmsg/virtio_rpmsg.h | 34 +++++++ samples/rpmsg/rpmsg_client_sample.c | 9 ++ 3 files changed, 144 insertions(+), 47 deletions(-) create mode 100644 include/linux/rpmsg/virtio_rpmsg.h base-commit: 85842b61f64cac93d28e129d35193e329d463fd1 -- 2.34.1
