USB: Add support to store lane count used by USB 3.2

USB 3.2 specification adds Dual-lane support, doubling the maximum
SuperSpeedPlus data rate from 10Gbps to 20Gbps.

Dual-lane takes into use a second set of rx and tx wires/pins in the
Type-C cable and connector.

Add "rx_lanes" and "tx_lanes" variables to struct usb_device to store
the numer of lanes in use. Number of lanes can be read using the extended
port status hub request that was introduced in USB 3.1.

Extended port status rx and tx lane count are zero based, maximum
lanes supported by non inter-chip (SSIC) USB 3.2 is 2 (dual lane) with
rx and tx lane count symmetric. SSIC devices support asymmetric lanes
up to 4 lanes per direction.

If extended port status is not available then default to one lane.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/core/hub.c

@@ -2746,6 +2746,14 @@ static int hub_port_wait_reset(struct usb_hub *hub, int port1,
 	if (!udev)
 		return 0;
 
+	if (hub_is_superspeedplus(hub->hdev)) {
+		/* extended portstatus Rx and Tx lane count are zero based */
+		udev->rx_lanes = USB_EXT_PORT_RX_LANES(ext_portstatus) + 1;
+		udev->tx_lanes = USB_EXT_PORT_TX_LANES(ext_portstatus) + 1;
+	} else {
+		udev->rx_lanes = 1;
+		udev->tx_lanes = 1;
+	}
 	if (hub_is_wusb(hub))
 		udev->speed = USB_SPEED_WIRELESS;
 	else if (hub_is_superspeedplus(hub->hdev) &&

include/linux/usb.h

@@ -551,6 +551,8 @@ struct usb3_lpm_parameters {
  * @route: tree topology hex string for use with xHCI
  * @state: device state: configured, not attached, etc.
  * @speed: device speed: high/full/low (or error)
+ * @rx_lanes: number of rx lanes in use, USB 3.2 adds dual-lane support
+ * @tx_lanes: number of tx lanes in use, USB 3.2 adds dual-lane support
  * @tt: Transaction Translator info; used with low/full speed dev, highspeed hub
  * @ttport: device port on that tt hub
  * @toggle: one bit for each endpoint, with ([0] = IN, [1] = OUT) endpoints
@@ -624,6 +626,8 @@ struct usb_device {
 	u32		route;
 	enum usb_device_state	state;
 	enum usb_device_speed	speed;
+	unsigned int		rx_lanes;
+	unsigned int		tx_lanes;
 
 	struct usb_tt	*tt;
 	int		ttport;

include/uapi/linux/usb/ch11.h

@@ -197,6 +197,11 @@ struct usb_port_status {
 #define USB_EXT_PORT_STAT_RX_LANES	0x00000f00
 #define USB_EXT_PORT_STAT_TX_LANES	0x0000f000
 
+#define USB_EXT_PORT_RX_LANES(p) \
+			(((p) & USB_EXT_PORT_STAT_RX_LANES) >> 8)
+#define USB_EXT_PORT_TX_LANES(p) \
+			(((p) & USB_EXT_PORT_STAT_TX_LANES) >> 12)
+
 /*
  * wHubCharacteristics (masks)
  * See USB 2.0 spec Table 11-13, offset 3