Date: Tue, 25 Jun 2024 16:28:25 +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: Re: [PATCH v2 1/2] bus: mhi: host: Import mux_id item

At 2024-06-25 15:44:49, "Manivannan Sadhasivam" <manivannan.sadhasivam@...aro.org> wrote:
>On Tue, Jun 25, 2024 at 10:10:17AM +0800, Slark Xiao wrote:
>> 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?
>> 
>
>Hmm, sadly we shouldn't have used the same controller config for all these
>devices across different product families. I didn't really paid attention to the
>device name which is supposed to be unique (that's my bad).
>
>For instance, because of the controller config reuse, your SDX62 modem would
>print:
>
>"MHI PCI device found: foxconn-sdx65"
>
>which clearly is misleading the users...
>
>I've submitted a patch that uses unique product name across the product families
>[1]. Please take a look. After this patch, you can use the modem name to
>differentiate in client drivers.
>
>- Mani
>
>[1] https://lore.kernel.org/mhi/20240625074148.7412-1-manivannan.sadhasivam@linaro.org/
>
>-- 
>மணிவண்ணன் சதாசிவம்
For same chip platform, I don't think it's necessary to separate into different parts.
Like t99w368 and DW5932e, all things are same except the 'name'. For previous
mux_id settings, we would like to add it for sdx72/sdx75 platforms, but shall
no difference on T99W515 and DW5934e. 
Otherwise, we must to update both mhi and wwan side if we have a new foxconn
SDX72 device support since the name is different with foxconn-t99w515 or
foxconn-dw5934e.

Thanks.

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