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From:   Mathieu Poirier <mathieu.poirier@linaro.org>
Date:   Mon, 28 Feb 2022 11:58:25 -0700
Message-ID: <CANLsYkzEhh2bCLQN-vqSqTfYvpR6VuYJYZNeUVCDSZ3VSAshhQ@mail.gmail.com>
Subject: Re: [RFC PATCH v3 0/4] remoteproc: restructure the remoteproc VirtIO device
To:     Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Cc:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com,
        Rob Herring <robh@kernel.org>, Christoph Hellwig <hch@lst.de>,
        Stefano Stabellini <stefanos@xilinx.com>,
        Bruce Ashfield <bruce.ashfield@xilinx.com>
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Good day,

On Wed, 26 Jan 2022 at 09:24, Arnaud Pouliquen
<arnaud.pouliquen@foss.st.com> wrote:
>
> Update from V2 [1]:
> In order to better handle error cases and to have something more symmetrical between
> the functions in charge of rvdev initialization/deletion, the patchset has been reworked.
>  - Introduction in the first patch, of rproc_vdev_data structure which allows to better
>    decorrelate the rproc from the management of the rvdev structure. This structure is reused
>    in the last patch of the series for the creation of the remoteproc virtio platform device.
>  - In addition to the previous version, the management of the vring lifecycle has been fully
>    migrated to the remoteproc_virtio.c (rproc_parse_vring, rproc_alloc_vring, rproc_free_vring)
>
> [1] https://lkml.org/lkml/2021/12/22/111
>
> Patchset description:
>
> This series is a part of the work initiated a long time ago in
> the series "remoteproc: Decorelate virtio from core"[2]
>
> 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 [3][4]
>

I started working on this set - comments to follow throughout the week.

Thanks,
Mathieu

> [2] https://lkml.org/lkml/2020/4/16/1817
> [3] https://lkml.org/lkml/2021/6/23/607
> [4] https://patchwork.kernel.org/project/linux-remoteproc/patch/AOKowLclCbOCKxyiJ71WeNyuAAj2q8EUtxrXbyky5E@cp7-web-042.plabs.ch/
>
> 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 (4):
>   remoteproc: core: Introduce virtio device add/remove functions
>   remoteproc: core: Introduce rproc_register_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     | 159 +++----------------
>  drivers/remoteproc/remoteproc_internal.h |  33 +++-
>  drivers/remoteproc/remoteproc_virtio.c   | 193 ++++++++++++++++++++---
>  include/linux/remoteproc.h               |   6 +-
>  4 files changed, 227 insertions(+), 164 deletions(-)
>
> --
> 2.25.1
>