[PATCH] i.MX6 PCIe: Fix imx6_pcie_deassert_core_reset() polarity

On Tue, Mar 29, 2016 at 9:13 AM, Roberto Fichera [off-list ref] wrote:

On 03/29/2016 05:10 PM, Tim Harvey wrote:

quoted

Arnd,

Right, on the IMX the MSI interrupt is GIC-120 which is also the
legacy INTD and I do see that if I happen to put a radio in a slot
where due to swizzling its pin1 becomes INTD (GIC-120) the interrupt
does fire and the device works. Any other slot using GIC-123 (INTA),
GIC-122 (INTB), or GIC-121 (INTC) never fires so its very possible
that something in the designware core is masking out the legacy irqs.
I would also think this was something IMX specific, but I really don't
see any codepaths in pci-imx6.c that would cause that: a driver
requesting a legacy PCI would get a GIC interrupt which is handled by
the IMX6 gpc interrupt controller.

Any dra7xxx, exynos, spear13xx, keystone, layerscape, hisi, qcom SoC
users of designware PCIe core out there that can verify PCI MSI and
legacy are both working at the same time?

Lucas is the expert here and I believe he has the documentation for
the designware core that Freescale doens't provide with the IMX6
documentation so hopefully he can provide some insight. He's the one
that has authored all the MSI support and has been using it.

I typically advise our users to 'not' enable MSI because
architecturally you can spread 4 distinct legacy irq's across CPU's
better than a single shared irq.

Don't know if I'm facing similar problem, however devices connected in miniPCI slot behind
a PCIe-to-PCI bridge (MSI is disabled) using INTA all is working ok, including shared IRQ.
In case of INTB will not work, and the GIC irq quite often get stuck.

Roberto,

What board/platform is this and what does /proc/interrupts look like?

This sounds like what would happen if the downstream interrupts on the
PCIe-to-PCI bridge are not mapped properly as was the case with a
board I support (in which case I had to work out a bootloader fixup
that placed a non-standard interrupt-map in the device-tree for the
bridge). What bridge are you using?

Tim