79b4c06112
Once we start supporting uas hardware, and as more and more uas devices become available, we will likely start seeing broken devices. This patch prepares for the inevitable need for blacklisting those devices from using the uas driver (they will use usb-storage instead). Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
52 lines
1.3 KiB
C
52 lines
1.3 KiB
C
#include <linux/usb.h>
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#include <linux/usb/hcd.h>
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static int uas_is_interface(struct usb_host_interface *intf)
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{
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return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
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intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
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intf->desc.bInterfaceProtocol == USB_PR_UAS);
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}
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static int uas_isnt_supported(struct usb_device *udev)
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{
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struct usb_hcd *hcd = bus_to_hcd(udev->bus);
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dev_warn(&udev->dev, "The driver for the USB controller %s does not "
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"support scatter-gather which is\n",
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hcd->driver->description);
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dev_warn(&udev->dev, "required by the UAS driver. Please try an"
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"alternative USB controller if you wish to use UAS.\n");
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return -ENODEV;
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}
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static int uas_find_uas_alt_setting(struct usb_interface *intf)
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{
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int i;
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struct usb_device *udev = interface_to_usbdev(intf);
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int sg_supported = udev->bus->sg_tablesize != 0;
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for (i = 0; i < intf->num_altsetting; i++) {
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struct usb_host_interface *alt = &intf->altsetting[i];
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if (uas_is_interface(alt)) {
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if (!sg_supported)
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return uas_isnt_supported(udev);
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return alt->desc.bAlternateSetting;
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}
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}
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return -ENODEV;
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}
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static int uas_use_uas_driver(struct usb_interface *intf,
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const struct usb_device_id *id)
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{
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unsigned long flags = id->driver_info;
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if (flags & US_FL_IGNORE_UAS)
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return 0;
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return uas_find_uas_alt_setting(intf) >= 0;
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}
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