Re: Re: Linux Kernel 6.6.36 and upstream mhi repo latest: Interface definition of sierra_em919x

["manivannan.sadhasivam" <manivannan.sadhasivam@linaro.org>]

On Mon, Jul 15, 2024 at 11:43:26AM +0800, Slark Xiao wrote:
> 
> At 2024-07-13 17:41:27, "Johannes Fischer" <johannes.fischer@verificationpartners.com> wrote:
> >Hi all,
> >@Stark,
> >first, I accept that changes may have side impact on other modems.
> >Please have in mind that I flashed SWIX55C_03.14.10.04 and the respective generic nvu a few days ago, so I assume to be quite close to default config.
> >
> >Using  the sierra_em919x config with IP links changed to MBIM in kernel I can establish data traffic; I do not see a component converting the MBIM stream to RMnet in Linux kernel (?). I wonder whether there is positive  confirmation about a EM919x working in PCIe mode with the current kernel config, in which mode? (We did not have trouble using the EM919x in USB mode.)
> >
> >About GPIO handling, as said there is none for for Full_Card_Power_off# (6, 10k pull-up to 3V3) and RESET# (67, just a C=100nF to GND) on the BPI-R4. 
> >We  have not validated the timing in BPI-R4 with 6.6.36 or current kernel versus the timing diagram at "AirPrime EM919X/EM7690 Product Technical Specification". As you said there may be a corner case that we end up 
> >with the Foxconn config due to timing at BPI-R4 power up times.
> >
> >I get from your statement, that the valid config should be sierra_em919x, thanks for this clarification.
> >
> 
> Yeah, I just checked this issue again. We met this issue in our ARM  platform.
> Device boot up shall through PBL->SBL->Kernel boot up. And there are 2 different PCIe settings between PBL and kernel side.
> When host mhi driver probed, your device may still in PBL  stage or SBL stage(the PCIe EP in device side is not ready), then you will get a "foxconn-config" since your PBL ID match with that one.
> Solution shall have these:
> 1. Update firmware side to keep ID same between PBL and kernel config.

Having 2 PCIe IDs for a single device doesn't sound right. If it is fixed in
successive firmware releases then fine, otherwise please fix it for all.

- Mani

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