On Tue, 21 May 2013, Heikki Krogerus wrote:
> From: "Chew, Chiau Ee" <[email protected]>
>
> Like the xHCI controller on Intel Panther Point and Lynx Point
> chipsets, the xHCI controller on Intel BayTrail has also ports that
> can be switched between the EHCI host controller.
>
> This patch should be backported to stable kernels as old as 3.0,
> that contain commit 69e848c2090aebba5698a1620604c7dccb448684
> "Intel xhci: Support EHCI/xHCI port switching.
>
> Signed-off-by: Chew, Chiau Ee <[email protected]>
> Signed-off-by: Heikki Krogerus <[email protected]>
> Cc: [email protected]
> ---
> drivers/usb/host/ehci-pci.c | 3 ++-
> drivers/usb/host/pci-quirks.c | 12 +++++++++++-
> 2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
> index 595d210..a5708d9 100644
> --- a/drivers/usb/host/ehci-pci.c
> +++ b/drivers/usb/host/ehci-pci.c
> @@ -322,7 +322,8 @@ static bool usb_is_intel_switchable_ehci(struct pci_dev
> *pdev)
> (pdev->device == 0x1E26 ||
> pdev->device == 0x8C2D ||
> pdev->device == 0x8C26 ||
> - pdev->device == 0x9C26);
> + pdev->device == 0x9C26 ||
> + pdev->device == 0x0F34);
The entries should be kept sorted in numerical order. In fact, you
might even interchange the 0x8C2D and 0x8C26 entries.
> }
>
> static void ehci_enable_xhci_companion(void)
> diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
> index 4c338ec..6062822 100644
> --- a/drivers/usb/host/pci-quirks.c
> +++ b/drivers/usb/host/pci-quirks.c
> @@ -724,6 +724,7 @@ static int handshake(void __iomem *ptr, u32 mask, u32
> done,
>
> #define PCI_DEVICE_ID_INTEL_LYNX_POINT_XHCI 0x8C31
> #define PCI_DEVICE_ID_INTEL_LYNX_POINT_LP_XHCI 0x9C31
> +#define PCI_DEVICE_ID_INTEL_BYT_XHCI 0x0F35
>
> bool usb_is_intel_ppt_switchable_xhci(struct pci_dev *pdev)
> {
> @@ -741,10 +742,19 @@ bool usb_is_intel_lpt_switchable_xhci(struct pci_dev
> *pdev)
> pdev->device == PCI_DEVICE_ID_INTEL_LYNX_POINT_LP_XHCI);
> }
>
> +/* And so does the Intel BayTrail. */
> +bool usb_is_intel_byt_switchable_xhci(struct pci_dev *pdev)
> +{
> + return pdev->class == PCI_CLASS_SERIAL_USB_XHCI &&
> + pdev->vendor == PCI_VENDOR_ID_INTEL &&
> + pdev->device == PCI_DEVICE_ID_INTEL_BYT_XHCI;
> +}
> +
> bool usb_is_intel_switchable_xhci(struct pci_dev *pdev)
> {
> return usb_is_intel_ppt_switchable_xhci(pdev) ||
> - usb_is_intel_lpt_switchable_xhci(pdev);
> + usb_is_intel_lpt_switchable_xhci(pdev) ||
> + usb_is_intel_byt_switchable_xhci(pdev);
> }
> EXPORT_SYMBOL_GPL(usb_is_intel_switchable_xhci);
This code cries out for refactoring. Why test pdev->class and
pdev->vendor in the same way in three different places? Those two
tests should be moved directly into usb_is_intel_switchable_xhci().
The other helper functions then become simple comparisons. As far as
I'm concerned, they also could be moved inline into
usb_is_intel_switchable_xhci(). Sarah may disagree, however.
Alan Stern
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