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Date:   Mon, 25 Apr 2022 10:59:45 +0200
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From:   Arnaud POULIQUEN <arnaud.pouliquen@foss.st.com>
Subject: Re: [PATCH V2 0/3] rpmsg and glink signaling API support
To:     Deepak Kumar Singh <quic_deesin@quicinc.com>,
        <bjorn.andersson@linaro.org>, <swboyd@chromium.org>,
        <quic_clew@quicinc.com>, <mathieu.poirier@linaro.org>
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        <linux-remoteproc@vger.kernel.org>
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Hi,

On 3/23/22 11:17, Arnaud POULIQUEN wrote:
> Hi all,
> 
> On 1/18/22 20:43, Deepak Kumar Singh wrote:
>> [Change from V1]
>> Fixed most of the review comments in V1.
> 
> This implementation works for the glink transport,
> But how to manage such flow control for other transport
> layer?
> From my POV it is important that it is also usable for
> by transport backends which doe not have such signaling.
> The idea here is not to implement in other backends yet, but
> at least to determine how it could be handled to avoid that
> tomorrow this has to be reworked. 

FYI, I've started some dev, trying to adapt the implementation to
the virtio backend to move forward with this topic.

It is only a POC for time being based on a new ROPMsg service for the
flow control.

Linux code is available here:
https://github.com/arnopo/linux/commits/signalling

openamp library associated code is available here:
https://github.com/arnopo/open-amp/commits/flow_ctrl

I hope to find some time next month to continue my dev and send patches
to the mailing list. 

Regards,
Arnaud


> 
> More than that I wonder if the flow control could also be used
> to solve the RPmsg protocol issue related to the channel
> announcement [1][2]
> 
> [1] https://github.com/OpenAMP/open-amp/pull/160
> [2] https://lore.kernel.org/lkml/20220316153001.662422-1-arnaud.pouliquen@foss.st.com/
> 
> Thanks,
> Arnaud


> 
>>
>> Deepak Kumar Singh (3):
>>   rpmsg: core: Add signal API support
>>   rpmsg: glink: Add support to handle signals command
>>   rpmsg: char: Add TIOCMGET/TIOCMSET ioctl support
>>
>>  drivers/rpmsg/qcom_glink_native.c | 77 +++++++++++++++++++++++++++++++++++++++
>>  drivers/rpmsg/rpmsg_char.c        | 47 ++++++++++++++++++++++--
>>  drivers/rpmsg/rpmsg_core.c        | 21 +++++++++++
>>  drivers/rpmsg/rpmsg_internal.h    |  2 +
>>  include/linux/rpmsg.h             | 14 +++++++
>>  5 files changed, 157 insertions(+), 4 deletions(-)
>>