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path: root/drivers/usb/storage/uas-detect.h
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Diffstat (limited to 'drivers/usb/storage/uas-detect.h')
-rw-r--r--drivers/usb/storage/uas-detect.h96
1 files changed, 96 insertions, 0 deletions
diff --git a/drivers/usb/storage/uas-detect.h b/drivers/usb/storage/uas-detect.h
new file mode 100644
index 000000000000..bb05b984d5f6
--- /dev/null
+++ b/drivers/usb/storage/uas-detect.h
@@ -0,0 +1,96 @@
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
+#include "usb.h"
+
+static int uas_is_interface(struct usb_host_interface *intf)
+{
+ return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
+ intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
+ intf->desc.bInterfaceProtocol == USB_PR_UAS);
+}
+
+static int uas_isnt_supported(struct usb_device *udev)
+{
+ struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+
+ dev_warn(&udev->dev, "The driver for the USB controller %s does not "
+ "support scatter-gather which is\n",
+ hcd->driver->description);
+ dev_warn(&udev->dev, "required by the UAS driver. Please try an"
+ "alternative USB controller if you wish to use UAS.\n");
+ return -ENODEV;
+}
+
+static int uas_find_uas_alt_setting(struct usb_interface *intf)
+{
+ int i;
+ struct usb_device *udev = interface_to_usbdev(intf);
+ int sg_supported = udev->bus->sg_tablesize != 0;
+
+ for (i = 0; i < intf->num_altsetting; i++) {
+ struct usb_host_interface *alt = &intf->altsetting[i];
+
+ if (uas_is_interface(alt)) {
+ if (!sg_supported)
+ return uas_isnt_supported(udev);
+ return alt->desc.bAlternateSetting;
+ }
+ }
+
+ return -ENODEV;
+}
+
+static int uas_find_endpoints(struct usb_host_interface *alt,
+ struct usb_host_endpoint *eps[])
+{
+ struct usb_host_endpoint *endpoint = alt->endpoint;
+ unsigned i, n_endpoints = alt->desc.bNumEndpoints;
+
+ for (i = 0; i < n_endpoints; i++) {
+ unsigned char *extra = endpoint[i].extra;
+ int len = endpoint[i].extralen;
+ while (len >= 3) {
+ if (extra[1] == USB_DT_PIPE_USAGE) {
+ unsigned pipe_id = extra[2];
+ if (pipe_id > 0 && pipe_id < 5)
+ eps[pipe_id - 1] = &endpoint[i];
+ break;
+ }
+ len -= extra[0];
+ extra += extra[0];
+ }
+ }
+
+ if (!eps[0] || !eps[1] || !eps[2] || !eps[3])
+ return -ENODEV;
+
+ return 0;
+}
+
+static int uas_use_uas_driver(struct usb_interface *intf,
+ const struct usb_device_id *id)
+{
+ struct usb_host_endpoint *eps[4] = { };
+ struct usb_device *udev = interface_to_usbdev(intf);
+ struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+ unsigned long flags = id->driver_info;
+ int r, alt;
+
+ usb_stor_adjust_quirks(udev, &flags);
+
+ if (flags & US_FL_IGNORE_UAS)
+ return 0;
+
+ if (udev->speed >= USB_SPEED_SUPER && !hcd->can_do_streams)
+ return 0;
+
+ alt = uas_find_uas_alt_setting(intf);
+ if (alt < 0)
+ return 0;
+
+ r = uas_find_endpoints(&intf->altsetting[alt], eps);
+ if (r < 0)
+ return 0;
+
+ return 1;
+}