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Message-ID: <20201112031415.GA2491@Mani-XPS-13-9360>
Date: Thu, 12 Nov 2020 08:44:15 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Jakub Kicinski <kuba@...nel.org>
Cc: Loic Poulain <loic.poulain@...aro.org>,
David Miller <davem@...emloft.net>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
cjhuang@...eaurora.org,
Network Development <netdev@...r.kernel.org>
Subject: Re: [PATCH v2 0/5] net: qrtr: Add distant node support
On Tue, Nov 10, 2020 at 09:44:27AM -0800, Jakub Kicinski wrote:
> On Tue, 10 Nov 2020 10:03:29 +0100 Loic Poulain wrote:
> > On Mon, 9 Nov 2020 at 19:39, Jakub Kicinski <kuba@...nel.org> wrote:
> > >
> > > On Mon, 9 Nov 2020 09:49:24 +0100 Loic Poulain wrote:
> > > > > Looks like patch 1 is a bug fix and patches 2-5 add a new feature.
> > > > > Is that correct?
> > > >
> > > > That's correct, though strictly speaking 2-5 are also bug fix since remote node
> > > > communication is supposed to be supported in QRTR to be compatible with
> > > > other implementations (downstream or private implementations).
> > >
> > > Is there a spec we can quote to support that, or is QRTR purely
> > > a vendor interface?
> >
> > There is no public spec AFAIK, this is a vendor interface.
> >
> > > What's the end user issue that we're solving? After firmware upgrade
> > > things stop working? Things don't work on HW platforms on which this
> > > was not tested? Don't work on new HW platforms?
> >
> > QRTR is usually something used in SoC context as communication
> > protocol for accessing the differents IPs (modem, WiFi, DSP, etc)
> > around the CPU. In that case, these components (nodes), identified
> > with a 'node ID', are directly reachable by the CPU (QRTR over shared
> > memory). This case is not impacted by the series, all nodes beeing CPU
> > immediate neighbours.
> >
> > But today QRTR is no more a ARCH_QCOM thing only, It is also exposed
> > as communication channel for QCOM based wireless modules (e.g. SDX55
> > modem), over PCIe/MHI. In that case, the host is only connected to the
> > Modem CPU QRTR endpoint that in turn gives access to other embedded
> > Modem endpoints, acting as a gateway/bridge for accessing
> > non-immediate nodes from the host. currently, this case is not working
> > and the series fix it.
> >
> > However, AFAIK, the only device would request this support is the
> > SDX55 PCIe module, that just landed in mhi-next. So I assume it's fine
> > if the related part of the series targets net-next.
>
> Thanks! Sounds like net-next will work just fine, but won't you need
> these changes in mhi-next, then? In which case you should send a pull
> request based on Linus' tree so that both Mani and netdev can pull it
> in.
>
> Mani, WDYT?
Sorry, missed this. mhi-next doesn't need these changes and since you've
applied to net-next, everything is fine!
I still need to apply the MHI patch which got applied to net-next and
provide an immutable branch to Kalle for another set of MHI patches...
Thanks,
Mani
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