linux-kernel - Re:Re: [PATCH v3 2/2] net: wwan: mhi: Add network support for Foxconn T99W760

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Message-ID: <20c33ad2.791f.19aa05c08c3.Coremail.slark_xiao@163.com>
Date: Thu, 20 Nov 2025 16:22:57 +0800 (CST)
From: "Slark Xiao" <slark_xiao@....com>
To: "Loic Poulain" <loic.poulain@....qualcomm.com>
Cc: "Manivannan Sadhasivam" <mani@...nel.org>,
	"Dmitry Baryshkov" <dmitry.baryshkov@....qualcomm.com>,
	ryazanov.s.a@...il.com, johannes@...solutions.net,
	andrew+netdev@...n.ch, davem@...emloft.net, edumazet@...gle.com,
	kuba@...nel.org, pabeni@...hat.com, mhi@...ts.linux.dev,
	linux-arm-msm@...r.kernel.org, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re:Re: [PATCH v3 2/2] net: wwan: mhi: Add network support for
 Foxconn T99W760

At 2025-11-20 15:44:14, "Loic Poulain" <loic.poulain@....qualcomm.com> wrote:
>On Thu, Nov 20, 2025 at 6:41 AM Manivannan Sadhasivam <mani@...nel.org> wrote:
>>
>> On Wed, Nov 19, 2025 at 02:08:33PM +0100, Loic Poulain wrote:
>> > On Wed, Nov 19, 2025 at 12:27 PM Dmitry Baryshkov
>> > <dmitry.baryshkov@....qualcomm.com> wrote:
>> > >
>> > > On Wed, Nov 19, 2025 at 06:56:15PM +0800, Slark Xiao wrote:
>> > > > T99W760 is designed based on Qualcomm SDX35 chip. It use similar
>> > > > architechture with SDX72/SDX75 chip. So we need to assign initial
>> > > > link id for this device to make sure network available.
>> > > >
>> > > > Signed-off-by: Slark Xiao <slark_xiao@....com>
>> > > > ---
>> > > >  drivers/net/wwan/mhi_wwan_mbim.c | 3 ++-
>> > > >  1 file changed, 2 insertions(+), 1 deletion(-)
>> > > >
>> > > > diff --git a/drivers/net/wwan/mhi_wwan_mbim.c b/drivers/net/wwan/mhi_wwan_mbim.c
>> > > > index c814fbd756a1..a142af59a91f 100644
>> > > > --- a/drivers/net/wwan/mhi_wwan_mbim.c
>> > > > +++ b/drivers/net/wwan/mhi_wwan_mbim.c
>> > > > @@ -98,7 +98,8 @@ static struct mhi_mbim_link *mhi_mbim_get_link_rcu(struct mhi_mbim_context *mbim
>> > > >  static int mhi_mbim_get_link_mux_id(struct mhi_controller *cntrl)
>> > > >  {
>> > > >       if (strcmp(cntrl->name, "foxconn-dw5934e") == 0 ||
>> > > > -         strcmp(cntrl->name, "foxconn-t99w515") == 0)
>> > > > +         strcmp(cntrl->name, "foxconn-t99w515") == 0 ||
>> > > > +         strcmp(cntrl->name, "foxconn-t99w760") == 0)
>> > >
>> > > Can we replace this list of strinc comparisons with some kind of device
>> > > data, being set in the mhi-pci-generic driver?
>> >
>> > If we move this MBIM-specific information into mhi-pci-generic, we
>> > should consider using a software node (e.g. via
>> > device_add_software_node) so that these properties can be accessed
>> > through the generic device-property API.
>> >
>>
>> MHI has to business in dealing with MBIM specific information as we already
>> concluded. So it should be handled within the WWAN subsystem.
>
>it doesn’t make sense to include MBIM-specific fields in a generic MHI
>structure. However, attaching fwnode properties could be reasonable
>since the MHI PCI driver is responsible for device enumeration, and
>that would keep device model specific handling fully covered in that
>driver.
>
>It’s fine to keep device-specific handling within WWAN/MBIM. However,
>next time, please introduce a dedicated device data structure for the
>mux-id instead of adding another strcmp.
>
Hi Loic,
So you answer is yes for this time. I appreciate it very much.
And I will commit another patch for fixing the name "t99w515" to 
"t99w640". I have updated it in mhi side in 2025/6.But I forgot to 
sync in MBIM side. Please refer to: 
https://lore.kernel.org/all/20250606095019.383992-1-slark_xiao@163.com/
Hope that commit won't break your decision.

To avoid such mismatch issue, I agree to use a new mechanism to
make it more convenient.
Currently, it seems only SDX75/SDX35 MBIM solution have this issue.
For whole MHI support products, only Foxconn fell into this trap.
So I hope community could help this for the new design.

Thanks