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 } 97