[RFC PATCH 0/7] remoteproc: restructure the remoteproc VirtIO device

[Arnaud Pouliquen]

This series is a part of the work initiate a long time ago in 
the series "remoteproc: Decorelate virtio from core"[1]


Objective of the work:
- Update the remoteproc VirtIO device creation (use platform device)
- Allow to declare remoteproc VirtIO device in DT
    - declare resources associated to a remote proc VirtIO
    - declare a list of VirtIO supported by the platform.
- Prepare the enhancement to more VirtIO devices (e.g audio, video, ...)
- Keep the legacy working!
- Try to improve the picture about concerns reported by Christoph Hellwing [2][3]

[1] https://lkml.org/lkml/2020/4/16/1817
[2] https://lkml.org/lkml/2021/6/23/607
[3] https://patchwork.kernel.org/project/linux-remoteproc/patch/AOKowLclCbOCKxyiJ71WeNyuAAj2q8EUtxrXbyky5E@xxxxxxxxxxxxxxxxxxxx/

In term of device tree this would result in such hiearchy (stm32mp1 example with 2 virtio RPMSG):

	m4_rproc: m4@10000000 {
		compatible = "st,stm32mp1-m4";
		reg = <0x10000000 0x40000>,
		      <0x30000000 0x40000>,
		      <0x38000000 0x10000>;
        memory-region = <&retram>, <&mcuram>,<&mcuram2>;
        mboxes = <&ipcc 2>, <&ipcc 3>;
        mbox-names = "shutdown", "detach";
        status = "okay";

        #address-cells = <1>;
        #size-cells = <0>;
        
        vdev@0 {
		compatible = "rproc-virtio";
		reg = <0>;
		virtio,id = <7>;  /* RPMSG */
		memory-region = <&vdev0vring0>, <&vdev0vring1>, <&vdev0buffer>;
		mboxes = <&ipcc 0>, <&ipcc 1>;
		mbox-names = "vq0", "vq1";
		status = "okay";
        };

        vdev@1 {
		compatible = "rproc-virtio";
		reg = <1>;
		virtio,id = <7>;  /*RPMSG */
		memory-region = <&vdev1vring0>, <&vdev1vring1>, <&vdev1buffer>;
		mboxes = <&ipcc 4>, <&ipcc 5>;
		mbox-names = "vq0", "vq1";
		status = "okay";
        };
};

I have divided the work in 4 steps to simplify the review, This series implements only
the step 1:
step 1:  redefine the remoteproc VirtIO device as a platform device
  - migrate rvdev management in remoteproc virtio.c,
  - create a remotproc virtio config ( can be disabled for platform that not use VirtIO IPC.
step 2: add possibility to declare and prob a VirtIO sub node
  - VirtIO bindings declaration,
  - multi DT VirtIO devices support,
  - introduction of a remote proc virtio bind device mechanism ,
=> https://github.com/arnopo/linux/commits/step2-virtio-in-DT
step 3: Add memory declaration in VirtIO subnode
=> https://github.com/arnopo/linux/commits/step3-virtio-memories
step 4: Add mailbox declaration in VirtIO subnode
=> https://github.com/arnopo/linux/commits/step4-virtio-mailboxes

Arnaud Pouliquen (7):
  remoteproc: core: Introduce virtio device add/remove functions
  remoteproc: Move rvdev management in rproc_virtio
  remoteproc: Remove vdev_to_rvdev and vdev_to_rproc from remoteproc API
  remoteproc: create the REMOTEPROC_VIRTIO config
  remoteproc: virtio: Create platform device for the remoteproc_virtio
  remoteproc: virtio: Add helper to create platform device
  remoteproc: Instantiate the new remoteproc virtio platform device

 drivers/remoteproc/Kconfig               |  11 +-
 drivers/remoteproc/Makefile              |   2 +-
 drivers/remoteproc/remoteproc_core.c     | 142 +++-------------
 drivers/remoteproc/remoteproc_internal.h |  52 +++++-
 drivers/remoteproc/remoteproc_virtio.c   | 207 +++++++++++++++++++++--
 include/linux/remoteproc.h               |  18 +-
 6 files changed, 282 insertions(+), 150 deletions(-)

-- 
2.17.1