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Subject: Re: [PATCH v5 00/16] introduce a generic IOCTL interface for RPMsg
 channels management
To:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Ohad Ben-Cohen <ohad@wizery.com>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Andy Gross <agross@kernel.org>
CC:     <linux-remoteproc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-msm@vger.kernel.org>
References: <20210219111501.14261-1-arnaud.pouliquen@foss.st.com>
From:   Arnaud POULIQUEN <arnaud.pouliquen@foss.st.com>
Message-ID: <8599da66-b7df-e4a5-fcf3-008620420372@foss.st.com>
Date:   Wed, 17 Mar 2021 10:29:47 +0100
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On 2/19/21 12:14 PM, Arnaud Pouliquen wrote:
> This series restructures the RPMsg char driver to decorrelate the control part and to
> create a generic RPMsg ioctl interface compatible with other RPMsg services.
> 
> The V4 and V5 fix compilation issues reported by the kernel test robot <lkp@intel.com>
> and analyzed by Dan Carpenter <dan.carpenter@oracle.com>.
> 
> The V3 is based on the guideline proposed by Mathieu Poirier to keep as much as possible
> the legacy implementation of the rpmsg_char used by the GLINK and SMD platforms.
> 
> Objectives of the series:
> - Allow to create a service from Linux user application:
>   - with a specific name
>   - with or without name service announcement.
> - Allow to probe the same service by receiving either a NS announcement from the remote firmware
>   or a Linux user application request.
> - Use these services independently of the RPMsg transport implementation (e.g be able to use
>   RPMSg char with the RPMsg virtio bus).
> 
> Steps in the series:
>   - Extract the control part of the char dev and create the rpmsg_ctrl.c file (patches 1 to 6)
>   - Enable the use of the chardev with the virtio backend (patches 7 to 11)
>   - Introduce the RPMSG_CREATE_DEV_IOCTL IOCTL to instantiate RPMsg devices (patch 12)
>     The application can then create or release a channel by specifying:
>        - the name service of the device to instantiate.   
>        - the source address.
>        - the destination address.
>   - Instantiate the /dev/rpmsg interface on remote NS announcement (patches 13 to 16)
> 
> In this revision, I do not divide the series into several parts in order to show a complete
> picture of the proposed evolution. To simplify the review, if requested, I can send it in
> several steps listed above.

No new revision of this series planned, but move forward by splitting it in 3
new series to ease the review.
The first step is addressed here:
https://patchwork.kernel.org/project/linux-remoteproc/list/?series=446305

> 
> Known current Limitations:
> - Tested only with virtio RPMsg bus. The glink and smd drivers adaptations have not been tested
>   (not able to test it).
> - For the virtio backend: No NS announcement is sent to the remote processor if the source
>   address is set to RPMSG_ADDR_ANY.
> - For the virtio backend: the existing RPMSG_CREATE_EPT_IOCTL is working but the endpoints are
>   not attached to an exiting channel.
> - to limit patches the pending RPMSG_DESTROY_DEV_IOCTL has not ben implemented. This will be
>   proposed in a second step.
> 
> This series can be applied on git/andersson/remoteproc.git for-next branch (d9ff3a5789cb).
> 
> This series can be tested using rpmsgexport, rpmsgcreatedev and ping tools available here:
> https://github.com/arnopo/rpmsgexport.git
> 
> Reference to the V4 discussion thread: https://lkml.org/lkml/2021/2/17/384
> 
> Arnaud Pouliquen (16):
>   rpmsg: char: rename rpmsg_char_init to rpmsg_chrdev_init
>   rpmsg: move RPMSG_ADDR_ANY in user API
>   rpmsg: add short description of the IOCTL defined in UAPI.
>   rpmsg: char: export eptdev create an destroy functions
>   rpmsg: char: dissociate the control device from the rpmsg class
>   rpmsg: move the rpmsg control device from rpmsg_char to rpmsg_ctrl
>   rpmsg: update rpmsg_chrdev_register_device function
>   rpmsg: glink: add sendto and trysendto ops
>   rpmsg: smd: add sendto and trysendto ops
>   rpmsg: char: use sendto to specify the message destination address
>   rpmsg: virtio: register the rpmsg_ctrl device
>   rpmsg: ctrl: introduce RPMSG_CREATE_DEV_IOCTL
>   rpmsg: char: introduce __rpmsg_chrdev_create_eptdev function
>   rpmsg: char: introduce a RPMsg driver for the RPMsg char device
>   rpmsg: char: no dynamic endpoint management for the default one
>   rpmsg: char: return an error if device already open
> 
>  drivers/rpmsg/Kconfig             |   9 ++
>  drivers/rpmsg/Makefile            |   1 +
>  drivers/rpmsg/qcom_glink_native.c |  18 ++-
>  drivers/rpmsg/qcom_smd.c          |  18 ++-
>  drivers/rpmsg/rpmsg_char.c        | 237 +++++++++++-------------------
>  drivers/rpmsg/rpmsg_char.h        |  51 +++++++
>  drivers/rpmsg/rpmsg_ctrl.c        | 229 +++++++++++++++++++++++++++++
>  drivers/rpmsg/rpmsg_internal.h    |  10 +-
>  drivers/rpmsg/virtio_rpmsg_bus.c  |  57 ++++++-
>  include/linux/rpmsg.h             |   3 +-
>  include/uapi/linux/rpmsg.h        |  18 ++-
>  11 files changed, 485 insertions(+), 166 deletions(-)
>  create mode 100644 drivers/rpmsg/rpmsg_char.h
>  create mode 100644 drivers/rpmsg/rpmsg_ctrl.c
>