drivers/usb/storage/uas-detect.h

   1 #include <linux/usb.h>
   2 #include <linux/usb/hcd.h>
   3 #include "usb.h"
   4
   5 static int uas_is_interface(struct usb_host_interface *intf)
   6 {
   7         return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
   8                 intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
   9                 intf->desc.bInterfaceProtocol == USB_PR_UAS);
  10 }
  11
  12 static int uas_isnt_supported(struct usb_device *udev)
  13 {
  14         struct usb_hcd *hcd = bus_to_hcd(udev->bus);
  15
  16         dev_warn(&udev->dev, "The driver for the USB controller %s does not "
  17                         "support scatter-gather which is\n",
  18                         hcd->driver->description);
  19         dev_warn(&udev->dev, "required by the UAS driver. Please try an"
  20                         "alternative USB controller if you wish to use UAS.\n");
  21         return -ENODEV;
  22 }
  23
  24 static int uas_find_uas_alt_setting(struct usb_interface *intf)
  25 {
  26         int i;
  27         struct usb_device *udev = interface_to_usbdev(intf);
  28         int sg_supported = udev->bus->sg_tablesize != 0;
  29
  30         for (i = 0; i < intf->num_altsetting; i++) {
  31                 struct usb_host_interface *alt = &intf->altsetting[i];
  32
  33                 if (uas_is_interface(alt)) {
  34                         if (!sg_supported)
  35                                 return uas_isnt_supported(udev);
  36                         return alt->desc.bAlternateSetting;
  37                 }
  38         }
  39
  40         return -ENODEV;
  41 }
  42
  43 static int uas_use_uas_driver(struct usb_interface *intf,
  44                               const struct usb_device_id *id)
  45 {
  46         struct usb_device *udev = interface_to_usbdev(intf);
  47         unsigned long flags = id->driver_info;
  48
  49         usb_stor_adjust_quirks(udev, &flags);
  50
  51         if (flags & US_FL_IGNORE_UAS)
  52                 return 0;
  53
  54         return uas_find_uas_alt_setting(intf) >= 0;
  55 }