[RFC PATCH 00/10] Introduction of rpmsg flow control service

[Arnaud Pouliquen]

This series proposes an implementation for the rpmsg virtio transport
backend, of the signaling API proposed by Deepak Kumar Singh:
"rpmsg and glink signaling API support" [1]

The aim of the series is to offer the possibility for an endpoint to inform
a remote endpoint about its state, based on a software flow control[2].

For this a new rpmsg service( with a fixed address 64) is proposed.
It is responsible for:
- transmitting local endpoint flow control information to the remote side,
- informing a local endpoint about a remote endpoint flow control.

For the rpmsg virtio transport layer the service is negotiated thanks to the 
virtio feature flag: VIRTIO_RPMSG_F_FC

Notice that this pull request introduces new feature in the rpmsg protocol,
So it has to be aligned with OpenAMP implementation.
Pending OpenAMP pull request is available here:
https://github.com/OpenAMP/open-amp/pull/394


[1]https://lkml.org/lkml/2022/1/18/867
[2]https://en.wikipedia.org/wiki/Software_flow_control

Arnaud Pouliquen (8):
  rpmsg: core: Add rpmsg device remote flow control announcement ops
  rpmsg: virtio: Implement the announce_remote_fc ops
  rpmsg: Introduce flow control channel driver
  rpmsg: virtio: Add support of the VIRTIO_RPMSG_F_FC feature
  rpmsg: virtio: Implement the set_flow_control ops
  rpmsg: Add the destination address in rpmsg_set_flow_control
  rpmsg: tty : Add the support of the flow control
  rpmsg: virtio: Set default dst address on flow control

Deepak Kumar Singh (2):
  rpmsg: core: Add signal API support
  rpmsg: char: Add TIOCMGET/TIOCMSET ioctl support

 drivers/rpmsg/Kconfig            |  11 +++
 drivers/rpmsg/Makefile           |   1 +
 drivers/rpmsg/rpmsg_char.c       |  56 +++++++++++++--
 drivers/rpmsg/rpmsg_core.c       |  47 +++++++++++++
 drivers/rpmsg/rpmsg_fc.c         | 113 +++++++++++++++++++++++++++++++
 drivers/rpmsg/rpmsg_internal.h   |   9 +++
 drivers/rpmsg/virtio_rpmsg_bus.c | 111 +++++++++++++++++++++++++++++-
 drivers/tty/rpmsg_tty.c          |  50 ++++++++++++++
 include/linux/rpmsg.h            |  15 ++++
 include/linux/rpmsg/fc.h         |  51 ++++++++++++++
 10 files changed, 456 insertions(+), 8 deletions(-)
 create mode 100644 drivers/rpmsg/rpmsg_fc.c
 create mode 100644 include/linux/rpmsg/fc.h

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2.25.1