[PATCH v9 0/4] remoteproc: restructure the remoteproc VirtIO device

[Arnaud Pouliquen]

1) Update from V8 [1]:

- rebase on for-next branch [2], to apply series on top of commit
 7d7f8fe4e399 ("remoteproc: Harden rproc_handle_vdev() against integer overflow")

[1] https://lkml.org/lkml/2022/8/26/532
[2] https://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux.git/commit/?h=for-next&id=c81b67199cc4e2e4e8caf1abbbca1dc1b80bc642

2) Patchset description:

This series is a part of the work initiated a long time ago in 
the series "remoteproc: Decorelate virtio from core"[3]

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 I2C, audio, video, ...).
  For instance be able to declare a I2C device in a virtio-i2C node.
- Keep the legacy working!
- Try to improve the picture about concerns reported by Christoph Hellwing [4][5]

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

In term of device tree this would result in such hierarchy (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 probe 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 (4):
  remoteproc: core: Introduce rproc_rvdev_add_device function
  remoteproc: core: Introduce rproc_add_rvdev function
  remoteproc: Move rproc_vdev management to remoteproc_virtio.c
  remoteproc: virtio: Create platform device for the remoteproc_virtio

 drivers/remoteproc/remoteproc_core.c     | 154 +++---------------
 drivers/remoteproc/remoteproc_internal.h |  23 ++-
 drivers/remoteproc/remoteproc_virtio.c   | 189 ++++++++++++++++++++---
 include/linux/remoteproc.h               |   6 +-
 4 files changed, 210 insertions(+), 162 deletions(-)

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2.24.3