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_find_endpoints(struct usb_host_interface *alt,
  44                               struct usb_host_endpoint *eps[])
  45 {
  46         struct usb_host_endpoint *endpoint = alt->endpoint;
  47         unsigned i, n_endpoints = alt->desc.bNumEndpoints;
  48
  49         for (i = 0; i < n_endpoints; i++) {
  50                 unsigned char *extra = endpoint[i].extra;
  51                 int len = endpoint[i].extralen;
  52                 while (len >= 3) {
  53                         if (extra[1] == USB_DT_PIPE_USAGE) {
  54                                 unsigned pipe_id = extra[2];
  55                                 if (pipe_id > 0 && pipe_id < 5)
  56                                         eps[pipe_id - 1] = &endpoint[i];
  57                                 break;
  58                         }
  59                         len -= extra[0];
  60                         extra += extra[0];
  61                 }
  62         }
  63
  64         if (!eps[0] || !eps[1] || !eps[2] || !eps[3])
  65                 return -ENODEV;
  66
  67         return 0;
  68 }
  69
  70 static int uas_use_uas_driver(struct usb_interface *intf,
  71                               const struct usb_device_id *id)
  72 {
  73         struct usb_host_endpoint *eps[4] = { };
  74         struct usb_device *udev = interface_to_usbdev(intf);
  75         struct usb_hcd *hcd = bus_to_hcd(udev->bus);
  76         unsigned long flags = id->driver_info;
  77         int r, alt;
  78
  79         usb_stor_adjust_quirks(udev, &flags);
  80
  81         if (flags & US_FL_IGNORE_UAS)
  82                 return 0;
  83
  84         if (udev->speed >= USB_SPEED_SUPER && !hcd->can_do_streams)
  85                 return 0;
  86
  87         alt = uas_find_uas_alt_setting(intf);
  88         if (alt < 0)
  89                 return 0;
  90
  91         r = uas_find_endpoints(&intf->altsetting[alt], eps);
  92         if (r < 0)
  93                 return 0;
  94
  95         return 1;
  96 }