From 82aa0387d52dd0db2173b844ad52d114807c189b Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Mon, 21 Oct 2013 08:53:31 +0100 Subject: uas: Move uas detect code to uas-detect.h This is a preparation patch for teaching usb-storage to not bind to uas devices. Signed-off-by: Hans de Goede Signed-off-by: Sarah Sharp --- drivers/usb/storage/uas-detect.h | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 drivers/usb/storage/uas-detect.h (limited to 'drivers/usb/storage/uas-detect.h') diff --git a/drivers/usb/storage/uas-detect.h b/drivers/usb/storage/uas-detect.h new file mode 100644 index 000000000000..28101c7e6a9f --- /dev/null +++ b/drivers/usb/storage/uas-detect.h @@ -0,0 +1,40 @@ +#include +#include + +static int uas_is_interface(struct usb_host_interface *intf) +{ + return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE && + intf->desc.bInterfaceSubClass == USB_SC_SCSI && + intf->desc.bInterfaceProtocol == USB_PR_UAS); +} + +static int uas_isnt_supported(struct usb_device *udev) +{ + struct usb_hcd *hcd = bus_to_hcd(udev->bus); + + dev_warn(&udev->dev, "The driver for the USB controller %s does not " + "support scatter-gather which is\n", + hcd->driver->description); + dev_warn(&udev->dev, "required by the UAS driver. Please try an" + "alternative USB controller if you wish to use UAS.\n"); + return -ENODEV; +} + +static int uas_find_uas_alt_setting(struct usb_interface *intf) +{ + int i; + struct usb_device *udev = interface_to_usbdev(intf); + int sg_supported = udev->bus->sg_tablesize != 0; + + for (i = 0; i < intf->num_altsetting; i++) { + struct usb_host_interface *alt = &intf->altsetting[i]; + + if (uas_is_interface(alt)) { + if (!sg_supported) + return uas_isnt_supported(udev); + return alt->desc.bAlternateSetting; + } + } + + return -ENODEV; +} -- cgit v1.2.3