Hi Andrew,

On Thu, Jan 10 2019, Andrew Lunn wrote:

On Thu, Jan 10, 2019 at 02:26:22PM +0200, Baruch Siach wrote:

quoted

Commit 3d71746c42 ("PCI: armada8k: Add support for gpio controlled reset
signal") added reset signal support. Reset is unconditionally asserted
and deasserted.

Unfortunately, that commit breaks boot on Macchiatobin when a Mellanox
NIC is in the PCIe slot.

It turns out that you can toggle the reset signal only once. Another
reset signal toggle makes access to PCI configuration registers stall
indefinitely. U-Boot toggles the Macchiatobin PCIe reset line already at
boot.

Hi Baruch

Is this double reset issue limited to just Mellanox NICs, or any
device in the PCIe slot?

This sounds more like a workaround than a fix. It would be good to
investigate further and determine which end of the PCIe link has the
problem.

Sven Auhagen reported the same issue with Intel NIC attached to
mini-PCIe slots on a custom Armada 8K design.

How would you suggest to investigate this issue?

baruch

--
     http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch@tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel