Re: [PATCH] PCI: amlogic: meson: Don't use FAST_LINK_MODE to set up link

From: Rob Herring
Date: Thu May 07 2020 - 17:03:20 EST


On Wed, 29 Apr 2020 17:42:30 +0100, Marc Zyngier wrote:
> My vim3l board stubbornly refuses to play ball with a bog
> standard PCIe switch (ASM1184e), spitting all kind of errors
> ranging from link never coming up to crazy things like downstream
> ports falling off the face of the planet.
>
> Upon investigating how the PCIe RC is configured, I found the
> following nugget: the Sysnopsys DWC PCIe Reference Manual, in the
> section dedicated to the PLCR register, describes bit 7 (FAST_LINK_MODE)
> as:
>
> "Sets all internal timers to fast mode for simulation purposes."
>
> I completely understand the need for setting this bit from a simulation
> perspective, but what I have on my desk is actual silicon, which
> expects timers to have a nominal value (and I expect this is the
> case for most people).
>
> Making sure the FAST_LINK_MODE bit is cleared when configuring the RC
> solves this problem.
>
> Fixes: 9c0ef6d34fdb ("PCI: amlogic: Add the Amlogic Meson PCIe controller driver")
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> ---
> drivers/pci/controller/dwc/pci-meson.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>

Acked-by: Rob Herring <robh@xxxxxxxxxx>