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_find_uas_alt_setting(struct usb_interface *intf)
  13 {
  14         int i;
  15
  16         for (i = 0; i < intf->num_altsetting; i++) {
  17                 struct usb_host_interface *alt = &intf->altsetting[i];
  18
  19                 if (uas_is_interface(alt))
  20                         return alt->desc.bAlternateSetting;
  21         }
  22
  23         return -ENODEV;
  24 }
  25
  26 static int uas_find_endpoints(struct usb_host_interface *alt,
  27                               struct usb_host_endpoint *eps[])
  28 {
  29         struct usb_host_endpoint *endpoint = alt->endpoint;
  30         unsigned i, n_endpoints = alt->desc.bNumEndpoints;
  31
  32         for (i = 0; i < n_endpoints; i++) {
  33                 unsigned char *extra = endpoint[i].extra;
  34                 int len = endpoint[i].extralen;
  35                 while (len >= 3) {
  36                         if (extra[1] == USB_DT_PIPE_USAGE) {
  37                                 unsigned pipe_id = extra[2];
  38                                 if (pipe_id > 0 && pipe_id < 5)
  39                                         eps[pipe_id - 1] = &endpoint[i];
  40                                 break;
  41                         }
  42                         len -= extra[0];
  43                         extra += extra[0];
  44                 }
  45         }
  46
  47         if (!eps[0] || !eps[1] || !eps[2] || !eps[3])
  48                 return -ENODEV;
  49
  50         return 0;
  51 }
  52
  53 static int uas_use_uas_driver(struct usb_interface *intf,
  54                               const struct usb_device_id *id)
  55 {
  56         struct usb_host_endpoint *eps[4] = { };
  57         struct usb_device *udev = interface_to_usbdev(intf);
  58         struct usb_hcd *hcd = bus_to_hcd(udev->bus);
  59         unsigned long flags = id->driver_info;
  60         int r, alt;
  61
  62         usb_stor_adjust_quirks(udev, &flags);
  63
  64         if (flags & US_FL_IGNORE_UAS)
  65                 return 0;
  66
  67         alt = uas_find_uas_alt_setting(intf);
  68         if (alt < 0)
  69                 return 0;
  70
  71         r = uas_find_endpoints(&intf->altsetting[alt], eps);
  72         if (r < 0)
  73                 return 0;
  74
  75         if (udev->bus->sg_tablesize == 0) {
  76                 dev_warn(&udev->dev,
  77                         "The driver for the USB controller %s does not support scatter-gather which is\n",
  78                         hcd->driver->description);
  79                 dev_warn(&udev->dev,
  80                         "required by the UAS driver. Please try an other USB controller if you wish to use UAS.\n");
  81                 return 0;
  82         }
  83
  84         if (udev->speed >= USB_SPEED_SUPER && !hcd->can_do_streams) {
  85                 dev_warn(&udev->dev,
  86                         "USB controller %s does not support streams, which are required by the UAS driver.\n",
  87                         hcd_to_bus(hcd)->bus_name);
  88                 dev_warn(&udev->dev,
  89                         "Please try an other USB controller if you wish to use UAS.\n");
  90                 return 0;
  91         }
  92
  93         return 1;
  94 }