Re: [PATCH v2 2/2] PCI: Override Synopsys USB 3.x HAPS device class

From: Bjorn Helgaas <helgaas@kernel.org>
To: Thinh Nguyen <thinh.nguyen@synopsys.com>
Cc: linux-pci@vger.kernel.org, linux-usb@vger.kernel.org,
	John Youn <john.youn@synopsys.com>
Subject: Re: [PATCH v2 2/2] PCI: Override Synopsys USB 3.x HAPS device class
Date: Mon, 17 Dec 2018 16:29:40 -0600	[thread overview]
Message-ID: <20181217222940.GE28981@google.com> (raw)
In-Reply-To: <8994fd7d7ee2bf5c1b32ce5bca25be4beb4405b5.1544478969.git.thinhn@synopsys.com>

On Mon, Dec 10, 2018 at 02:08:01PM -0800, Thinh Nguyen wrote:
> Synopsys USB 3.x host HAPS platform has a class code of
> PCI_CLASS_SERIAL_USB_XHCI, and xhci driver can claim it. However, these
> devices should use dwc3-haps driver. Change these devices' class code to
> PCI_CLASS_SERIAL_USB_DEVICE to prevent the xhci-pci driver from claiming
> them.
> 
> Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>

I applied both of these to pci/misc for v4.21, thanks!

> ---
> Change in v2:
> - Revise title to fit PCI patches' convention
> - Override pci class instead of driver
> 
>  drivers/pci/quirks.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 4700d24e5d55..c84f81c42a1f 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -618,6 +618,32 @@ static void quirk_amd_nl_class(struct pci_dev *pdev)
>  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_NL_USB,
>  		quirk_amd_nl_class);
>  
> +/*
> + * Synopsys USB 3.x host HAPS platform has a class code of
> + * PCI_CLASS_SERIAL_USB_XHCI, and xhci driver can claim it. However, these
> + * devices should use dwc3-haps driver. Change these devices' class code to
> + * PCI_CLASS_SERIAL_USB_DEVICE to prevent the xhci-pci driver from claiming
> + * them.
> + */
> +static void quirk_synopsys_haps(struct pci_dev *pdev)
> +{
> +	u32 class = pdev->class;
> +
> +	switch (pdev->device) {
> +	case PCI_DEVICE_ID_SYNOPSYS_HAPSUSB3:
> +	case PCI_DEVICE_ID_SYNOPSYS_HAPSUSB3_AXI:
> +	case PCI_DEVICE_ID_SYNOPSYS_HAPSUSB31:
> +		pdev->class = PCI_CLASS_SERIAL_USB_DEVICE;
> +		pci_info(pdev, "PCI class overridden (%#08x -> %#08x) so dwc3 driver can claim this instead of xhci\n",
> +			 class, pdev->class);
> +		break;
> +	default:
> +		return;

I dropped this "default: return;" because it's superfluous.

> +	}
> +}
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_SYNOPSYS, PCI_ANY_ID,
> +			 quirk_synopsys_haps);
> +
>  /*
>   * Let's make the southbridge information explicit instead of having to
>   * worry about people probing the ACPI areas, for example.. (Yes, it
> -- 
> 2.11.0
> 