[PATCH] PCI: brcmstb: Restore initial fundamental reset

Phil Elwell phil at raspberrypi.com
Thu Nov 12 12:13:20 EST 2020

On Thu, 12 Nov 2020 at 16:47, Lukas Wunner <lukas at wunner.de> wrote:
> On Thu, Nov 12, 2020 at 04:42:28PM +0000, Phil Elwell wrote:
> > On Thu, 12 Nov 2020 at 16:28, Jim Quinlan <james.quinlan at broadcom.com> wrote:
> > > As for me considering that  this line is superfluous -- which
> > > apparently it is not : AFAIK PERST# is always asserted from cold start
> > > on all Brcm STB SOCs, and I expected the same on the RPi.  Asserting
> > > PERST# at this point in time should be a no-op.  Is this not the case?
> >
> > The reason it isn't superfluous here is that when using USB to boot,
> > the Raspberry Pi BCM2711 firmware will already have configured the
> > PCIe bus once, so another reset is necessary.
> I think that begs the question why the firmware doesn't reset the
> PCIe bus before handing over control to the kernel?

Are you advocating removing all resets that merely reapply the
power-on reset state?


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