On Tue, 4 Jun 2013, Arnd Bergmann wrote:
> The three options USB_ARCH_HAS_{EHCI,OHCI,XHCI} are all well beyond
> their recommended shelf life. They have caused numerous build failures
> over the years because they are never completely correct, and with
> the move to splitting out the platform specific back-ends out of the
> driver, there is no real need for them any more. Also, the use of making
> USB_ARCH_HAS_HCD depend on it is questionable since one can always enable
> dummy_hc these days.
>
> This patch enables them unconditionally for all platforms and
> architectures, which means it is now possible to build host controller
> drivers for machines that are known not to come with this hardware,
> but that is just how we treat most other drivers.
>
> In order to minimise the impact on existing architecture code and
> defconfig files, all the Kconfig are left present for now. All platforms
> that currently do 'select USB_ARCH_HAS_*' should subsequently be changed
> not to select that. All drivers depending on USB_ARCH_HAS_HCD should
> be changed to depend on USB_SUPPORT instead.
This is a good idea.
> diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
> index 92e1dc9..654cd81 100644
> --- a/drivers/usb/Kconfig
> +++ b/drivers/usb/Kconfig
> -# some non-PCI HCDs implement xHCI
> @@ -71,19 +27,8 @@ config USB_COMMON
> default y
> depends on USB || USB_GADGET
>
> -# Host-side USB depends on having a host controller
> -# NOTE: dummy_hcd is always an option, but it's ignored here ...
> -# NOTE: SL-811 option should be board-specific ...
> config USB_ARCH_HAS_HCD
> - boolean
> - default y if USB_ARCH_HAS_OHCI
> - default y if USB_ARCH_HAS_EHCI
> - default y if USB_ARCH_HAS_XHCI
> - default y if PCMCIA && !M32R # sl811_cs
> - default y if ARM # SL-811
> - default y if BLACKFIN # SL-811
> - default y if SUPERH # r8a66597-hcd
> - default PCI
> + def_bool HAS_IOMEM
Instead of doing this, it makes more sense to enable USB_ARCH_HAS_HCD
whenever host-side USB is enabled. In other words,
def_bool USB
The HAS_IOMEM won't matter, because USB is defined only when
USB_SUPPORT is enabled, and USB_SUPPORT already depends on HAS_IOMEM.
Of course, it will then be necessary to remove the dependency on
USB_ARCH_HAS_HCD from the "config USB" entry. Which is exactly what
you're trying to accomplish, anyway.
> diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
> index e060ecf..045f9d27 100644
> --- a/drivers/usb/host/Kconfig
> +++ b/drivers/usb/host/Kconfig
> @@ -17,7 +17,7 @@ config USB_C67X00_HCD
>
> config USB_XHCI_HCD
> tristate "xHCI HCD (USB 3.0) support"
> - depends on USB_ARCH_HAS_XHCI
> + depends on PCI
You probably don't want to add this dependency. After all, one of the
comments removed above points out that there are non-PCI xHCI
controllers.
Alan Stern
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