Re: [PATCH v2 0/7] Add the iMX8MP PCIe support

[Lucas Stach]

Hi Richard,

Am Montag, dem 11.04.2022 um 03:32 +0000 schrieb Hongxing Zhu:
> > -----Original Message-----
> > From: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> > Sent: 2022年4月8日 16:13
> > To: Hongxing Zhu <hongxing.zhu@xxxxxxx>; tharvey@xxxxxxxxxxxxx;
> > Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
> > Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>; bhelgaas@xxxxxxxxxx;
> > Lorenzo
> > Pieralisi <lorenzo.pieralisi@xxxxxxx>; Rob Herring
> > <robh@xxxxxxxxxx>; Shawn
> > Guo <shawnguo@xxxxxxxxxx>; Vinod Koul <vkoul@xxxxxxxxxx>;
> > linux-phy@xxxxxxxxxxxxxxxxxxx; Device Tree Mailing List
> > <devicetree@xxxxxxxxxxxxxxx>; linux-pci@xxxxxxxxxxxxxxx; Linux ARM
> > Mailing
> > List <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>; open list
> > <linux-kernel@xxxxxxxxxxxxxxx>; Sascha Hauer
> > <kernel@xxxxxxxxxxxxxx>;
> > dl-linux-imx <linux-imx@xxxxxxx>
> > Subject: Re: [PATCH v2 0/7] Add the iMX8MP PCIe support
> > 
> > Am Freitag, dem 08.04.2022 um 03:14 +0000 schrieb Hongxing Zhu:
> > > > 
> > [...]
> > > > Richard,
> > > > 
> > > > Thanks for working on this!
> > > > 
> > > > Do you plan on submitting another version soon? I've tried to
> > > > test
> > > > this with an imx8mp board I'm bringing up and while the host
> > > > controller enumerates I fail to get a link to a device. It's
> > > > very
> > > > likely I am missing something as this series depends on the
> > > > IMX8MP blk-ctrl
> > and gpc series which I also can't cleanly apply.
> > > > Lucas just submitted a 'consolidated i.MX8MP HSIO/MEDIA/HDMI
> > > > blk-ctrl series' [1] yet I can't find a repo/branch that
> > > > applies to either.
> > > > 
> > > > Perhaps you have a git repo somewhere I can look at while we
> > > > wait
> > > > for imx8mp blk-ctl/gpc to settle and you to submit a v3?
> > > Hi Tim:
> > > Thanks for your kindly help to do the tests.
> > > I had listed the dependencies in the cover-letter log.
> > > Alexander and I used to test this series commits based on the
> > > V5.17 kernel.
> > > 
> > > Lucas had provided some review comments and suggestions about the
> > > PLL
> > > bits
> > >  manipulations of HSIOMIX in i.MX8MP PCIe PHY driver #3 of this
> > > series.
> > > And he suggested to let the HSIOMIX blk-ctrl make this PLL as a
> > > real
> > > clock,
> > >  and used by i.MX8MP PCIe PHY driver later.
> > > 
> > > Although I have some confusions, it's better let's wating for the
> > > blk-ctrl settle down and get clear discussion with Lucas later.
> > > How do you think about that?
> > 
> > Just to let you know my plans: I was quite busy with getting the
> > i.MX8MP
> > HDMI part to work. Now that this is at least in a state where it
> > can collect
> > some feedback from upstream I have some time to circle back to this
> > topic. I
> > can't commit to do it immediately, but I'll get around to looking
> > at the PCIe
> > series a bit more in-depth and apply my HSIO PLL suggestion to the
> > blk-ctrl
> > driver during the next week.
> 
> Hi Lucas:
> Thanks for your helpful reply.
> I know that you're busy with the blk-ctrl settle down now, and had
> explained to
> Tim.

Yesterday I tried to get this series working on my 8MP-EVK board, but
was unsuccessful for now. The PCIe link does not come up. PCIe REF_CLK
is present and PERST de-asserted. I'm not sure if this is due to a
faulty EP device (I don't have another M.2 KeyE device around to check)
or if this may be due to the old revision of my 8MP-EVK, as I'm still
working with a RevA board. The schematic revision log doesn't show
anything that would obviously influence PCIe operation, but I have also
not found any schematics for RevA.

Do you know if there have been any PCIe related changes/fixes in the
later EVK board revisions?

For now I'll try to get this working on a custom i.MX8MP board, where I
can use a different EP device. Maybe I'll have a bit more luck there.

Regards,
Lucas