Date: Tue, 25 Jun 2024 10:10:17 +0800 (CST)
From: "Slark Xiao" <slark_xiao@....com>
To: "Manivannan Sadhasivam" <manivannan.sadhasivam@...aro.org>
Cc: "Jeffrey Hugo" <quic_jhugo@...cinc.com>, 
	"Loic Poulain" <loic.poulain@...aro.org>, ryazanov.s.a@...il.com, 
	johannes@...solutions.net, netdev@...r.kernel.org, 
	mhi@...ts.linux.dev, linux-arm-msm@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re:Re: Re: [PATCH v2 1/2] bus: mhi: host: Import mux_id item

At 2024-06-23 21:44:30, "Manivannan Sadhasivam" <manivannan.sadhasivam@...aro.org> wrote:
>On Fri, Jun 21, 2024 at 11:17:16AM +0800, Slark Xiao wrote:
>> 
>> At 2024-06-14 22:31:03, "Jeffrey Hugo" <quic_jhugo@...cinc.com> wrote:
>> >On 6/14/2024 4:17 AM, Loic Poulain wrote:
>> >> On Wed, 12 Jun 2024 at 16:51, Manivannan Sadhasivam
>> >> <manivannan.sadhasivam@...aro.org> wrote:
>> >>>
>> >>> On Wed, Jun 12, 2024 at 08:19:13AM -0600, Jeffrey Hugo wrote:
>> >>>> On 6/12/2024 3:46 AM, Manivannan Sadhasivam wrote:
>> >>>>> On Wed, Jun 12, 2024 at 05:38:42PM +0800, Slark Xiao wrote:
>> >>>>>
>> >>>>> Subject could be improved:
>> >>>>>
>> >>>>> bus: mhi: host: Add configurable mux_id for MBIM mode
>> >>>>>
>> >>>>>> For SDX72 MBIM mode, it starts data mux id from 112 instead of 0.
>> >>>>>> This would lead to device can't ping outside successfully.
>> >>>>>> Also MBIM side would report "bad packet session (112)".
>> >>>>>> So we add a default mux_id value for SDX72. And this value
>> >>>>>> would be transferred to wwan mbim side.
>> >>>>>>
>> >>>>>> Signed-off-by: Slark Xiao <slark_xiao@....com>
>> >>>>>> ---
>> >>>>>>    drivers/bus/mhi/host/pci_generic.c | 3 +++
>> >>>>>>    include/linux/mhi.h                | 2 ++
>> >>>>>>    2 files changed, 5 insertions(+)
>> >>>>>>
>> >>>>>> diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c
>> >>>>>> index 0b483c7c76a1..9e9adf8320d2 100644
>> >>>>>> --- a/drivers/bus/mhi/host/pci_generic.c
>> >>>>>> +++ b/drivers/bus/mhi/host/pci_generic.c
>> >>>>>> @@ -53,6 +53,7 @@ struct mhi_pci_dev_info {
>> >>>>>>            unsigned int dma_data_width;
>> >>>>>>            unsigned int mru_default;
>> >>>>>>            bool sideband_wake;
>> >>>>>> + unsigned int mux_id;
>> >>>>>>    };
>> >>>>>>    #define MHI_CHANNEL_CONFIG_UL(ch_num, ch_name, el_count, ev_ring) \
>> >>>>>> @@ -469,6 +470,7 @@ static const struct mhi_pci_dev_info mhi_foxconn_sdx72_info = {
>> >>>>>>            .dma_data_width = 32,
>> >>>>>>            .mru_default = 32768,
>> >>>>>>            .sideband_wake = false,
>> >>>>>> + .mux_id = 112,
>> >>>>>>    };
>> >>>>>>    static const struct mhi_channel_config mhi_mv3x_channels[] = {
>> >>>>>> @@ -1035,6 +1037,7 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>> >>>>>>            mhi_cntrl->runtime_get = mhi_pci_runtime_get;
>> >>>>>>            mhi_cntrl->runtime_put = mhi_pci_runtime_put;
>> >>>>>>            mhi_cntrl->mru = info->mru_default;
>> >>>>>> + mhi_cntrl->link_id = info->mux_id;
>> >>>>>
>> >>>>> Again, 'link_id' is just a WWAN term. Use 'mux_id' here also.
>> >>>>
>> >>>> Does this really belong in MHI?  If this was DT, I don't think we would put
>> >>>> this value in DT, but rather have the driver (MBIM) detect the device and
>> >>>> code in the required value.
>> >>>>
>> >>>
>> >>> I believe this is a modem value rather than MHI. But I was OK with keeping it in
>> >>> MHI driver since we kind of keep modem specific config.
>> >>>
>> >>> But if WWAN can detect the device and apply the config, I'm all over it.
>> >> 
>> >> That would require at least some information from the MHI bus for the
>> >> MBIM driver
>> >> to make a decision, such as a generic device ID, or quirk flags...
>> >
>> >I don't see why.
>> >
>> >The "simple" way to do it would be to have the controller define a 
>> >different channel name, and then have the MBIM driver probe on that. 
>> >The MBIM driver could attach driver data saying that it needs to have a 
>> >specific mux_id.
>> >
>> >Or, with zero MHI/Controller changes, the MBIM driver could parse the 
>> >mhi_device struct, get to the struct device, for the underlying device, 
>> >and extract the PCIe Device ID and match that to a white list of known 
>> >devices that need this property.
>> >
>> >I guess if the controller could attach a private void * to the 
>> >mhi_device that is opaque to MHI, but allows MBIM to make a decision, 
>> >that would be ok.  Such a mechanism would be generic, and extensible to 
>> >other usecases of the same "class".
>> >
>> >-Jeff
>> 
>> Hi guys,
>> This patch mainly refer to the feature of mru setting between mhi and wwan side.
>> We ransfer this value to wwan side if we define it in mhi side, otherwise a default
>> value would be used in wwan side. Why don't we just align with that?
>> 
>
>Well, the problem is that MRU has nothing to do with MHI. I initially thought
>that it could fit inside the controller config, but thinking more I agree with
>Jeff that this doesn't belong to MHI at all.
>
>At the same time, I also do not want to extract the PCI info from the client
>drivers since the underlying transport could change with MHI. So the best
>solution I can think of is exposing the modem name in 'mhi_controller_config' so
>that the client drivers can do a match.
>
>Please try to implement that.
>
>- Mani
>
>-- 
>மணிவண்ணன் சதாசிவம்
Hi Mani,
Currently there are many products share a same mhi_controller_config
settings. For example, all foxconn device use modem_foxconn_sdx55_config.
But my device may be a SDX24, or SDX72, or even SDX65.  Any other idea?

Thanks

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