Date:   Fri, 25 Mar 2022 18:05:03 +0100
From:   Arnaud POULIQUEN <arnaud.pouliquen@...s.st.com>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>
CC:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        <linux-remoteproc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>, <julien.massot@....bzh>
Subject: Re: [PATCH v9 00/11] Restructure the rpmsg_char driver and introduce
 rpmsg_ctrl driver



On 3/25/22 16:59, Mathieu Poirier wrote:
> On Thu, Mar 24, 2022 at 06:36:23PM +0100, Arnaud POULIQUEN wrote:
>> Hi Bjorn,
>>
>> On 1/24/22 11:25, Arnaud Pouliquen wrote:
>>> Updates from V8 [1]:
>>> - rebase on 5.17-rc1 + rpmsg char cdev release fixes[2][3]
>>> - updates based on Bjorn Andersson's comments:
>>>   - remove rpmsg_create_default_ept API, set directly the ept->priv in rpmsg_chrdev_probe
>>>     function.
>>>   - rework commit message in [8/9]rpmsg: char: Introduce the "rpmsg-raw" channel
>>>
>>> Patchset description:
>>>
>>> The current rpmsg_char module implements a /dev/rpmsg_ctrl interface that provides the ability to
>>> instantiate char devices (/dev/rpmsgX) associated with an rpmsg endpoint for communication with the
>>> remote processor.
>>> This implementation fits with QCOM rpmsg backend but not with the magement by chanel implemented
>>> in the generic rpmsg virtio backend.
>>> This series restructures the rpmsg_char driver to decorrelate the control part from the data part
>>> in order to improve its compatible with the rpmsg virtio backend.
>>>
>>> Objective:
>>> - Expose a /dev/rpmsg_ctrlX interface for the application that is no longer dedicated to the
>>>   rpmsg_char but generalized to all rpmsg services. This offers capability to create and destroy
>>>   rpmsg channels from a user's application initiative (using the new RPMSG_CREATE_DEV_IOCTL and
>>>   RPMSG_DESTROY_DEV_IOCTL controls).
>>>   An application will be able to create/establish an rpmsg communication channel to communicate
>>>   with the remote processor, and not only wait the remote processor initiative.
>>>   This is interesting for example to establish a temporary communication link for diagnosis,
>>>   calibration, debugging... or instantiate  new data flows on some user actions.
>>> - Add capability to probe the rpmsg_char device at the initiative of the remote processor
>>>  (rpmsg service announcement mechanism).
>>>   This allows platforms based on the rpmsg virtio backend to create the /dev/rpmgX interface with
>>>   a rpmsg name service announcement.
>>>
>>> Subsets:
>>>   - Extract the control part of the char dev and create the rpmsg_ctrl.c file (patches 1 to 6)
>>>   - Introduce the "rpmsg-raw" channel in rpmsg_char(patches 7 to 10)
>>>   - Introduce the RPMSG_CREATE_DEV_IOCTL IOCTL and RPMSG_DESTROY_DEV_IOCTL to instantiate RPMsg
>>>     devices (patch 11)
>>>     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.
>>>
>>> This series has be applied and tested on 'commit e783362eb54c ("Linux 5.17-rc1") +
>>> rpmsg_char cdev release fixes [2][3]
>>>
>>> [1] https://lkml.org/lkml/2021/12/7/186
>>> [2] https://lkml.org/lkml/2022/1/10/1129
>>> [3] https://lkml.org/lkml/2022/1/10/1130
>>>
>>> Arnaud Pouliquen (11):
>>>   rpmsg: char: Export eptdev create and destroy functions
>>>   rpmsg: Create the rpmsg class in core instead of in rpmsg char
>>>   rpmsg: Move the rpmsg control device from rpmsg_char to rpmsg_ctrl
>>
>>
>>>   arm: configs: Configs that had RPMSG_CHAR now get RPMSG_CTRL
>>>   RISC-V: configs: Configs that had RPMSG_CHAR now get RPMSG_CTRL
>>>   arm64: defconfig: Config that had RPMSG_CHAR now gets RPMSG_CTRL
>>
>> Thank you for merging this series!
>>
>> I can't see in the "for next" branch[1] the 3 patches above that update configs
>> Are you expecting a specific action from me?   
> 
> Those patches will need to go through the Arm, RISC-V and arm64 subsystems.  The
> mailing list for those subsystems has been CC'ed but that isn't enough to get
> the maintainers' attention.  
> 
> I suggest sending another patchset with those 3 patches that CC the maintainers
> directly.  For the Arm patch I suggest adding Linus Walleij.

I will do what you suggest. 

My concerns in this case is about the scheduling of the integration.
I suppose that sending a second patchset for configs requests that the
rpmsg char series is first applied
But on the other hand this may lead to some failures as the RPMSG_CTRL is now
needed to create the /dev/rpmsg_ctrl0

so probably, I need to do this as fixup patch.

FYI the RISC-V patch as been reviewed by Anup Patel

Thanks,
Arnaud

> 
> Thanks,
> Mathieu
> 
>>
>> [1]https://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux.git
>>
>> Regards,
>> Arnaud
>>
>>>   rpmsg: Update rpmsg_chrdev_register_device function
>>>   rpmsg: char: Refactor rpmsg_chrdev_eptdev_create function
>>>   rpmsg: char: Add possibility to use default endpoint of the rpmsg
>>>     device
>>>   rpmsg: char: Introduce the "rpmsg-raw" channel
>>>   rpmsg: ctrl: Introduce new RPMSG_CREATE/RELEASE_DEV_IOCTL controls
>>>
>>>  arch/arm/configs/qcom_defconfig   |   1 +
>>>  arch/arm64/configs/defconfig      |   1 +
>>>  arch/riscv/configs/defconfig      |   1 +
>>>  arch/riscv/configs/rv32_defconfig |   1 +
>>>  drivers/rpmsg/Kconfig             |   8 +
>>>  drivers/rpmsg/Makefile            |   1 +
>>>  drivers/rpmsg/qcom_glink_native.c |   2 +-
>>>  drivers/rpmsg/qcom_smd.c          |   2 +-
>>>  drivers/rpmsg/rpmsg_char.c        | 231 +++++++++++-----------------
>>>  drivers/rpmsg/rpmsg_char.h        |  46 ++++++
>>>  drivers/rpmsg/rpmsg_core.c        |  15 +-
>>>  drivers/rpmsg/rpmsg_ctrl.c        | 243 ++++++++++++++++++++++++++++++
>>>  drivers/rpmsg/rpmsg_internal.h    |  10 +-
>>>  drivers/rpmsg/virtio_rpmsg_bus.c  |   2 +-
>>>  include/uapi/linux/rpmsg.h        |  10 ++
>>>  15 files changed, 419 insertions(+), 155 deletions(-)
>>>  create mode 100644 drivers/rpmsg/rpmsg_char.h
>>>  create mode 100644 drivers/rpmsg/rpmsg_ctrl.c
>>>

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