Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230606123119.57499-1-manivannan.sadhasivam@linaro.org>
 <c769c95d-e8cb-4cf6-a41a-9bef5a786bb1@lunn.ch> <20230607065652.GA5025@thinkpad>
In-Reply-To: <20230607065652.GA5025@thinkpad>
From:   Loic Poulain <loic.poulain@linaro.org>
Date:   Wed, 7 Jun 2023 09:12:00 +0200
Message-ID: <CAMZdPi-xJAj_eFvosVTmSzA99m3eYhrwoKPfBk-qH87yZzNupQ@mail.gmail.com>
Subject: Re: [PATCH 0/3] Add MHI Endpoint network driver
To:     Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc:     Andrew Lunn <andrew@lunn.ch>, davem@davemloft.net,
        edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
        mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Wed, 7 Jun 2023 at 08:56, Manivannan Sadhasivam
<manivannan.sadhasivam@linaro.org> wrote:
>
> On Tue, Jun 06, 2023 at 02:59:00PM +0200, Andrew Lunn wrote:
> > On Tue, Jun 06, 2023 at 06:01:16PM +0530, Manivannan Sadhasivam wrote:
> > > Hi,
> > >
> > > This series adds a network driver for the Modem Host Interface (MHI) endpoint
> > > devices that provides network interfaces to the PCIe based Qualcomm endpoint
> > > devices supporting MHI bus (like Modems). This driver allows the MHI endpoint
> > > devices to establish IP communication with the host machines (x86, ARM64) over
> > > MHI bus.
> > >
> > > On the host side, the existing mhi_net driver provides the network connectivity
> > > to the host.
> > >
> > > - Mani
> > >
> > > Manivannan Sadhasivam (3):
> > >   net: Add MHI Endpoint network driver
> > >   MAINTAINERS: Add entry for MHI networking drivers under MHI bus
> > >   net: mhi: Increase the default MTU from 16K to 32K
> > >
> > >  MAINTAINERS              |   1 +
> > >  drivers/net/Kconfig      |   9 ++
> > >  drivers/net/Makefile     |   1 +
> > >  drivers/net/mhi_ep_net.c | 331 +++++++++++++++++++++++++++++++++++++++
> > >  drivers/net/mhi_net.c    |   2 +-
> >
> > Should we add a drivers/net/modem directory? Maybe modem is too
> > generic, we want something which represents GSM, LTE, UMTS, 3G, 4G,
> > 5G, ... XG etc.
> >
>
> The generic modem hierarchy sounds good to me because most of the times a
> single driver handles multiple technologies. The existing drivers supporting
> modems are already under different hierarchy like usb, wwan etc... So unifying
> them makes sense. But someone from networking community should take a call.


Yes, so there is already a drivers/net/wwan directory for this, in
which there are drivers for control and data path, that together
represent a given 'wwan' (modem) entity. So the generic mhi_net could
be moved there, but the point is AFAIU, that MHI, despite his name, is
not (more) used only for modem, but as a generic memory sharing based
transport protocol, such as virtio. It would then not be necessarily
true that a peripheral exposing MHI net channel is actually a modem?

Regards,
Loic