Re: [PATCH v4 05/16] PCI: quirk dma_alias_devfn for Marvell devices

[Bjorn Helgaas <bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>]

On Thu, May 22, 2014 at 05:07:55PM -0600, Alex Williamson wrote:
> Several Marvell devices and a JMicron device have a similar DMA
> requester ID problem to Ricoh, except they use function 1 as the
> PCIe requester ID.  Add a quirk for these to populate the DMA
> function alias bitmap.

What's the DMA function alias bitmap?

> Signed-off-by: Alex Williamson <alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  drivers/pci/quirks.c |   36 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index bc8ebd9..923689f 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -3349,6 +3349,42 @@ static void quirk_dma_func0_alias(struct pci_dev *dev)
>  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_RICOH, 0xe832, quirk_dma_func0_alias);
>  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_RICOH, 0xe476, quirk_dma_func0_alias);
>  
> +static void quirk_dma_func1_alias(struct pci_dev *dev)
> +{
> +	if (PCI_FUNC(dev->devfn) != 1) {
> +		dev->dma_alias_devfn = PCI_DEVFN(PCI_SLOT(dev->devfn), 1);
> +		dev->dev_flags |= PCI_DEV_FLAGS_DMA_ALIAS_DEVFN;
> +	}
> +}
> +
> +/*
> + * Marvell 88SE9123 uses function 1 as the requester ID for DMA.  In some
> + * SKUs function 1 is present and is a legacy IDE controller, in other
> + * SKUs this function is not present, making this a ghost requester.
> + * https://bugzilla.kernel.org/show_bug.cgi?id=42679
> + */
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MARVELL_EXT, 0x9123,
> +			 quirk_dma_func1_alias);
> +/* https://bugzilla.kernel.org/show_bug.cgi?id=42679#c14 */
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MARVELL_EXT, 0x9130,
> +			 quirk_dma_func1_alias);
> +/* https://bugzilla.kernel.org/show_bug.cgi?id=42679#c47 + c57 */
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MARVELL_EXT, 0x9172,
> +			 quirk_dma_func1_alias);
> +/* https://bugzilla.kernel.org/show_bug.cgi?id=42679#c59 */
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MARVELL_EXT, 0x917a,
> +			 quirk_dma_func1_alias);
> +/* https://bugzilla.kernel.org/show_bug.cgi?id=42679#c46 */
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MARVELL_EXT, 0x91a0,
> +			 quirk_dma_func1_alias);
> +/* https://bugzilla.kernel.org/show_bug.cgi?id=42679#c49 */
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MARVELL_EXT, 0x9230,
> +			 quirk_dma_func1_alias);
> +/* https://bugs.gentoo.org/show_bug.cgi?id=497630 */
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_JMICRON,
> +			 PCI_DEVICE_ID_JMICRON_JMB388_ESD,
> +			 quirk_dma_func1_alias);
> +
>  static struct pci_dev *pci_func_0_dma_source(struct pci_dev *dev)
>  {
>  	if (!PCI_FUNC(dev->devfn))
>