[PATCH v4 0/5] virtio_rpmsg: make rpmsg channel configurable

[Loic Pallardy]

This goal of this series is to offer more flexibility for virtio_rpmsg
communication link configuration.

It should be possible to tune rpmsg buffer size per Rpmsg link, to provide
selected configuration to coprocessor, to take into account coprocessor
specificities like memory region.

This series introduces an optional virtio rpmsg configuration structure, which
will be managed as an extension of struct fw_rsc_vdev present in coprocessor firmware
resource table.
Structure access is possible thanks to virtio get and set API.
This structure contains the different information to tune the link between the
host and the coprocessor.

Patch "rpmsg: virtio_rpmsg_bus: fix sg_set_buf() when addr is not a valid
kernel address" has the same goal as Wendy's RFC [1]. I don't have tested
Wendy's series with level driver buffer allocation.

Last patch "rpmsg: virtio_rpmsg: set buffer configuration to virtio" has a
dependency with remoteproc subdevice boot sequence as coprocessor resource
table must be updated before coprocessor start. See [2]

[1] http://www.spinics.net/lists/linux-remoteproc/msg00852.html
[2] http://www.spinics.net/lists/linux-remoteproc/msg00826.html

---
Changes from v1:
- No more dependency with [2]. Coprocessor firmware should wait for first kick
indicating virtio rpmsg link ready before accessing resource table information.
- Correct issues reported by Suman
- Fix warnings found by checkpatch with --strict option

Changes from v2:
- Fix warnings reported by kbuild test robot

Changes from v3:
After discussions with Bjorn, virtual address sharing between low level driver
and virtio_rpmsg could be replaced by associated a dedicated memory region to
vdev and changing virtio_rpmsg allocation from dev->parent->parent to
dev->parent, i.e. vdev and not rproc device.
The advantage of the solution is that there will be only few changes in
virtio_rpmsg layer and it will be common with virtio_console driver.
These will be part of a dedicated patch series.
So v4 drops previous patch 5 "rpmsg: virtio_rpmsg: don't allocate buffer if
provided by low level driver" dealing with buffer previously allocated and va
fields from struct virtio_rpmsg_cfg.
In addition, patch series has been rebased on kernel 4.11-rc4.


Loic Pallardy (5):
  rpmsg: virtio_rpmsg: set rpmsg_buf_size customizable
  rpmsg: virtio_rpmsg_bus: fix sg_set_buf() when addr is not a valid
    kernel address
  include: virtio_rpmsg: add virtio rpmsg configuration structure
  rpmsg: virtio_rpmsg: get buffer configuration from virtio
  rpmsg: virtio_rpmsg: set buffer configuration to virtio

 drivers/rpmsg/virtio_rpmsg_bus.c   | 123 +++++++++++++++++++++++++++++++++----
 include/linux/rpmsg/virtio_rpmsg.h |  30 +++++++++
 2 files changed, 141 insertions(+), 12 deletions(-)
 create mode 100644 include/linux/rpmsg/virtio_rpmsg.h

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1.9.1