Re: [PATCH V3] PCI: rcar: Add the suspend/resume for pcie-rcar driver

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Lorenzo,

On Tue, Apr 28, 2020 at 10:26 AM Lorenzo Pieralisi
<lorenzo.pieralisi@arm.com> wrote:
> On Mon, Apr 27, 2020 at 10:08:52PM +0200, Geert Uytterhoeven wrote:
> > On Mon, Apr 27, 2020 at 7:41 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
> > > On Sat, Apr 25, 2020 at 10:55:21AM +0200, Geert Uytterhoeven wrote:
> > > > On Fri, Apr 24, 2020 at 9:57 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
> > > > > [+cc Vaibhav]
> > > > >
> > > > > Alternate less redundant subject:
> > > > >
> > > > >   PCI: rcar: Add suspend/resume support
> > > >
> > > > Note that there's both pcie-rcar.c (this driver, for R-Car Gen2 and Gen3
> > > > PCIe) and pci-rcar-gen2.c (for R-Car Gen2 PCI).
> > > > People tend to use the prefix "PCI: rcar: " for both :-(
> > >
> > > Yeah, that's pretty broken, thanks for pointing this out!
> > >
> > > For most drivers we use a chipset name ("keystone", "imx6", "tegra",
> > > etc) as the changlog tag.  That's nice because it gives space for
> > > multiple drivers from the same vendor, but I don't know anything
> > > similarly specific for the R-Car drivers.
> > >
> > > pci-rcar-gen2.c seems to be for some sort of internal Conventional PCI
> >
> > AFAIUI it's some internal PCI glue to the *HCI USB controller.
> >
> > > bus?  The "gen2" is confusing because "Gen 2" is more commonly used
> > > for PCIe than for Conventional PCI.
> >
> > The "Gen2" applies to "R-Car", not to "PCI".
>
> Wicked :) !

pcie-rcar.c supports R-Car Gen1, Gen2, and Gen3.

> > > I would propose keeping "rcar" for the PCIe driver and using
> > > "rcar-pci" for the Conventional PCI one, but the Conventional PCI one
> >
> > (/me resists against bike-shedding)
>
> I'd agree with Bjorn - I don't know, internal vs external seems
> artificial. Certainly gen2 is misleading, it does not take much
> to improve it.

We have lots of drivers in other subsystems with "rcar-gen2" or
"rcar-gen3" as part of their names.

> > > (pci-rcar-gen2.c) seems pretty inactive.  The most recent commits are
> > > from 2018, and they're trivial cleanups.  So I'm doubtful that anybody
> > > will remember when the next change comes in.
> >
> > I guess pci-rcar-gen2.c is simpler and more mature ;-)
> > R-Car Gen2 SoCs have both (internal) PCI and PCIe, so the two drivers
> > can be used together on the same hardware.
>
> I'd remove gen2 to start with, you are better placed to know the
> internals to come up with something significant.

So we're back at "PCI: rcar: ...", for both ;-)

I'd say the main difference between the two drivers is PCI vs. PCIe.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds