[PATCH 3/3] PCI: imx6: ventana: fixup for IRQ mismapping

[Jingoo Han]

On Friday, February 28, 2014 10:20 AM, Tim Harvey wrote:
> 
> The TI XIO2001 PCIe-to-PCI bridge used on Ventana expansion boards
> has its slot-to-bridge IRQ mapping reversed from the PCI specification:
> 
>   INTA->INTD
>   INTB->INTC
>   INTC->INTB
>   INTD->INTA

(+cc Marek Vasut, Pratyush Anand, Kishon Vijay Abraham I, Mohit KUMAR DCG)

As I mention earlier, 'i.MX6 PCIe IP' is not a culprit.
The 'TI XIO2001 PCIe-to-PCI bridge' is the culprit, right?

Then, './drivers/pci/host/pci-imx6.c' is not a good place
to fix the board problems.

Look at other i.MX6 boards. They don't have the 'TI XIO2001
PCIe-to-PCI bridge'. Please don't add this board specific 
code to SoC specific driver code.

Best regards,
Jingoo Han

> 
> Implement a custom swizzle function that does a fixup on the interrupt for
> devices on the first TI XIO2001 bridge in the tree.
> 
> Signed-off-by: Tim Harvey <tharvey at gateworks.com>
> Cc: Bjorn Helgaas <bhelgaas at google.com>
> Cc: Richard Zhu <r65037 at freescale.com>
> Cc: Shawn Guo <shawn.guo at linaro.org>
> Cc: Lucas Stach <l.stach at pengutronix.de>
> Cc: Sean Cross <xobs at kosagi.com>
> Cc: Jingoo Han <jg1.han at samsung.com>
> ---
>  drivers/pci/host/pci-imx6.c | 36 ++++++++++++++++++++++++++++++++++++
>  include/linux/pci_ids.h     |  1 +
>  2 files changed, 37 insertions(+)
> 
> diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
> index aaa05c8..b171a21 100644
> --- a/drivers/pci/host/pci-imx6.c
> +++ b/drivers/pci/host/pci-imx6.c
> @@ -493,6 +493,39 @@ static int imx6_add_pcie_port(struct pcie_port *pp,
>  	return 0;
>  }
> 
> +/* TI XIO2001 PCIe-to-PCI bridge on GW16082 exp card has IRQs reversed */
> +u8 ventana_swizzle(struct pci_dev *dev, u8 *pin)
> +{
> +	u8 i = 0;
> +	struct pci_dev *pdev = dev;
> +
> +	/* count number of TI XIO2001 bridges on bus */
> +	while (!pci_is_root_bus(pdev->bus)) {
> +		if (pdev->bus && pdev->bus->self &&
> +		    (pdev->bus->self->vendor == PCI_VENDOR_ID_TI) &&
> +		    (pdev->bus->self->device == PCI_DEVICE_ID_TI_XIO2001)) {
> +			i++;
> +		}
> +		pdev = pdev->bus->self;
> +	}
> +	while (!pci_is_root_bus(dev->bus)) {
> +		/* if we are directly downstream from 1st TI XIO2001 bridge */
> +		if (dev->bus && dev->bus->self &&
> +		    (dev->bus->self->vendor == PCI_VENDOR_ID_TI) &&
> +		    (dev->bus->self->device == PCI_DEVICE_ID_TI_XIO2001)) {
> +			if (--i == 0) {
> +				/* swap IRQs and swizzle backwards */
> +				*pin = (15 - PCI_SLOT(dev->devfn)) + 1;
> +				dev = dev->bus->self;
> +				continue;
> +			}
> +		}
> +		*pin = pci_swizzle_interrupt_pin(dev, *pin);
> +		dev = dev->bus->self;
> +	}
> +	return PCI_SLOT(dev->devfn);
> +}
> +
>  static int __init imx6_pcie_probe(struct platform_device *pdev)
>  {
>  	struct imx6_pcie *imx6_pcie;
> @@ -601,6 +634,9 @@ static int __init imx6_pcie_probe(struct platform_device *pdev)
>  		return PTR_ERR(imx6_pcie->iomuxc_gpr);
>  	}
> 
> +	if (of_machine_is_compatible("gw,ventana"))
> +		pp->swizzle = ventana_swizzle;
> +
>  	ret = imx6_add_pcie_port(pp, pdev);
>  	if (ret < 0)
>  		return ret;
> diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
> index 97fbecd..4ca334f 100644
> --- a/include/linux/pci_ids.h
> +++ b/include/linux/pci_ids.h
> @@ -822,6 +822,7 @@
>  #define PCI_DEVICE_ID_TI_XX12		0x8039
>  #define PCI_DEVICE_ID_TI_XX12_FM	0x803b
>  #define PCI_DEVICE_ID_TI_XIO2000A	0x8231
> +#define PCI_DEVICE_ID_TI_XIO2001	0x8240
>  #define PCI_DEVICE_ID_TI_1130		0xac12
>  #define PCI_DEVICE_ID_TI_1031		0xac13
>  #define PCI_DEVICE_ID_TI_1131		0xac15
> --
> 1.8.3.2