1 files changed, 143 insertions, 0 deletions
diff --git a/kernel/drivers/usb/storage/uas-detect.h b/kernel/drivers/usb/storage/uas-detect.h
new file mode 100644
index 000000000..f58caa9e6
--- /dev/null
+++ b/kernel/drivers/usb/storage/uas-detect.h
@@ -0,0 +1,143 @@
+#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_find_uas_alt_setting(struct usb_interface *intf)
+{
+	int i;
+
+	for (i = 0; i < intf->num_altsetting; i++) {
+		struct usb_host_interface *alt = &intf->altsetting[i];
+
+		if (uas_is_interface(alt))
+			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,
+			      unsigned long *flags_ret)
+{
+	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;
+
+
+	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;
+
+	/*
+	 * ASMedia has a number of usb3 to sata bridge chips, at the time of
+	 * this writing the following versions exist:
+	 * ASM1051 - no uas support version
+	 * ASM1051 - with broken (*) uas support
+	 * ASM1053 - with working uas support, but problems with large xfers
+	 * ASM1153 - with working uas support
+	 *
+	 * Devices with these chips re-use a number of device-ids over the
+	 * entire line, so the device-id is useless to determine if we're
+	 * dealing with an ASM1051 (which we want to avoid).
+	 *
+	 * The ASM1153 can be identified by config.MaxPower == 0,
+	 * where as the ASM105x models have config.MaxPower == 36.
+	 *
+	 * Differentiating between the ASM1053 and ASM1051 is trickier, when
+	 * connected over USB-3 we can look at the number of streams supported,
+	 * ASM1051 supports 32 streams, where as early ASM1053 versions support
+	 * 16 streams, newer ASM1053-s also support 32 streams, but have a
+	 * different prod-id.
+	 *
+	 * (*) ASM1051 chips do work with UAS with some disks (with the
+	 *     US_FL_NO_REPORT_OPCODES quirk), but are broken with other disks
+	 */
+	if (le16_to_cpu(udev->descriptor.idVendor) == 0x174c &&
+			(le16_to_cpu(udev->descriptor.idProduct) == 0x5106 ||
+			 le16_to_cpu(udev->descriptor.idProduct) == 0x55aa)) {
+		if (udev->actconfig->desc.bMaxPower == 0) {
+			/* ASM1153, do nothing */
+		} else if (udev->speed < USB_SPEED_SUPER) {
+			/* No streams info, assume ASM1051 */
+			flags |= US_FL_IGNORE_UAS;
+		} else if (usb_ss_max_streams(&eps[1]->ss_ep_comp) == 32) {
+			/* Possibly an ASM1051, disable uas */
+			flags |= US_FL_IGNORE_UAS;
+		} else {
+			/* ASM1053, these have issues with large transfers */
+			flags |= US_FL_MAX_SECTORS_240;
+		}
+	}
+
+	usb_stor_adjust_quirks(udev, &flags);
+
+	if (flags & US_FL_IGNORE_UAS) {
+		dev_warn(&udev->dev,
+			"UAS is blacklisted for this device, using usb-storage instead\n");
+		return 0;
+	}
+
+	if (udev->bus->sg_tablesize == 0) {
+		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 other USB controller if you wish to use UAS.\n");
+		return 0;
+	}
+
+	if (udev->speed >= USB_SPEED_SUPER && !hcd->can_do_streams) {
+		dev_warn(&udev->dev,
+			"USB controller %s does not support streams, which are required by the UAS driver.\n",
+			hcd_to_bus(hcd)->bus_name);
+		dev_warn(&udev->dev,
+			"Please try an other USB controller if you wish to use UAS.\n");
+		return 0;
+	}
+
+	if (flags_ret)
+		*flags_ret = flags;
+
+	return 1;
+}