Re: [PATCH 2/2] arm: dts: rk356x: rock3a: disable pcie3x2

[Marco Felsch <m.felsch@pengutronix.de>]

On 26-01-21, Ahmad Fatoum wrote:
> Hello Marco,
> 
> On 1/21/26 01:07, Marco Felsch wrote:
> > Hi Ahmad,
> > 
> > On 26-01-20, Ahmad Fatoum wrote:
> >> The board hangs occasionally on PCI probe after:
> >>
> >>   phy7: lane number 0, val 1
> >>
> >> On other boots, it continues to:
> >>
> >>   rockchip-dw-pcie 3c0800000.pcie@fe280000.of: Phy link never came up
> >>
> >> In both cases, the hang affects the second PCIe host controller
> >> to probe and the first probe never hangs:
> >>
> >>   rockchip-dw-pcie 3c0000000.pcie@fe260000.of: Phy link never came up
> >>
> >> This hang happens on the very first read access to the PCI controller
> >> at register PCIE_ATU_VIEWPORT. Reading Linux code, the first access
> >> seems to be to PCIE_VERSION_NUMBER (0x8F8), but accessing that in
> >> barebox equally hangs from time to time.
> >>
> >> My board doesn't have any PCIe devices connected and this hang
> >> doesn't happen in Linux and doesn't happen on the QNAP
> >> TS433-eU, which is also RK3568, but actually has PCIe devices, which are
> >> probed normally.
> >>
> >> Disable the device in barebox, so the board is usable with
> >> rockchip_v8_defconfig, which enables the PCI driver.
> >> barebox,status is used, so the Linux device tree is not affected.
> > 
> > The barebox internal device-tree is passed to Linux? Else we just can
> > make use of the "normal" status field since it would be not propagated
> > to Linux as well.
> 
> With barebox as EFI loader, we always install the barebox DT in a configuration
> table and leaves it to grub or whatever to decide whether it wants to use it or
> if it wants to use another DT it finds itself.

Ah, thanks for the explanation :) this wasn't clear to me. Maybe it's
worth a comment when to use this within the barebox,status description.

That beeing said, is it worth tying to make it barebox unspecific and
try to upstream the binding. I had something like bootloader,status or
bl33,status in my mind.

> The support for the Android fastboot's protocol boot command also doesn't pass
> a DT and expects the bootloader to pass its.

Good to know :)

Thanks,
  Marco

> 
> Cheers,
> Ahmad
> > 
> > Regards,
> >   Marco
> > 
> >> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> >> ---
> >>  arch/arm/dts/rk3568-rock-3a.dts | 4 ++++
> >>  1 file changed, 4 insertions(+)
> >>
> >> diff --git a/arch/arm/dts/rk3568-rock-3a.dts b/arch/arm/dts/rk3568-rock-3a.dts
> >> index bcbfab14a580..b7258d7e61b3 100644
> >> --- a/arch/arm/dts/rk3568-rock-3a.dts
> >> +++ b/arch/arm/dts/rk3568-rock-3a.dts
> >> @@ -55,3 +55,7 @@ environment_sd: partition@408000 {
> >>  		};
> >>  	};
> >>  };
> >> +
> >> +&pcie3x2 {
> >> +	barebox,status = "disabled";
> >> +};
> >> -- 
> >> 2.47.3
> >>
> >>
> >>
> > 
> 
> 
> -- 
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