xhci: Add a SuperSpeedPlus capability descriptor for xhci USB 3.1 roothub

All usb devices that support USB 3.1 Gen2 speeds need to provide a
SuperSpeedPlus device capability descriptor as part of their BOS
descriptor.

If the xhci controller supports USB 3.1 enhanced SuperSpeed, meaning
it can handle both Gen1 SuperSpeed 5Gbps and Gen2 SuperSpeedPlus 10Gbps
devices, then we need to provide a SuperSpeedPlus capability descriptor
for the USB 3.1 roothub as well.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-hub.c

@@ -31,13 +31,15 @@
 #define	PORT_RWC_BITS	(PORT_CSC | PORT_PEC | PORT_WRC | PORT_OCC | \
 			 PORT_RC | PORT_PLC | PORT_PE)
 
-/* USB 3.0 BOS descriptor and a capability descriptor, combined */
+/* USB 3 BOS descriptor and a capability descriptors, combined.
+ * Fields will be adjusted and added later in xhci_create_usb3_bos_desc()
+ */
 static u8 usb_bos_descriptor [] = {
 	USB_DT_BOS_SIZE,		/*  __u8 bLength, 5 bytes */
 	USB_DT_BOS,			/*  __u8 bDescriptorType */
 	0x0F, 0x00,			/*  __le16 wTotalLength, 15 bytes */
 	0x1,				/*  __u8 bNumDeviceCaps */
-	/* First device capability */
+	/* First device capability, SuperSpeed */
 	USB_DT_USB_SS_CAP_SIZE,		/*  __u8 bLength, 10 bytes */
 	USB_DT_DEVICE_CAPABILITY,	/* Device Capability */
 	USB_SS_CAP_TYPE,		/* bDevCapabilityType, SUPERSPEED_USB */
@@ -46,9 +48,108 @@ static u8 usb_bos_descriptor [] = {
 	0x03,				/* bFunctionalitySupport,
 					   USB 3.0 speed only */
 	0x00,				/* bU1DevExitLat, set later. */
-	0x00, 0x00			/* __le16 bU2DevExitLat, set later. */
+	0x00, 0x00,			/* __le16 bU2DevExitLat, set later. */
+	/* Second device capability, SuperSpeedPlus */
+	0x0c,				/* bLength 12, will be adjusted later */
+	USB_DT_DEVICE_CAPABILITY,	/* Device Capability */
+	USB_SSP_CAP_TYPE,		/* bDevCapabilityType SUPERSPEED_PLUS */
+	0x00,				/* bReserved 0 */
+	0x00, 0x00, 0x00, 0x00,		/* bmAttributes, get from xhci psic */
+	0x00, 0x00,			/* wFunctionalitySupport */
+	0x00, 0x00,			/* wReserved 0 */
+	/* Sublink Speed Attributes are added in xhci_create_usb3_bos_desc() */
 };
 
+static int xhci_create_usb3_bos_desc(struct xhci_hcd *xhci, char *buf,
+				     u16 wLength)
+{
+	int i, ssa_count;
+	u32 temp;
+	u16 desc_size, ssp_cap_size, ssa_size = 0;
+	bool usb3_1 = false;
+
+	desc_size = USB_DT_BOS_SIZE + USB_DT_USB_SS_CAP_SIZE;
+	ssp_cap_size = sizeof(usb_bos_descriptor) - desc_size;
+
+	/* does xhci support USB 3.1 Enhanced SuperSpeed */
+	if (xhci->usb3_rhub.min_rev >= 0x01 && xhci->usb3_rhub.psi_uid_count) {
+		/* two SSA entries for each unique PSI ID, one RX and one TX */
+		ssa_count = xhci->usb3_rhub.psi_uid_count * 2;
+		ssa_size = ssa_count * sizeof(u32);
+		desc_size += ssp_cap_size;
+		usb3_1 = true;
+	}
+	memcpy(buf, &usb_bos_descriptor, min(desc_size, wLength));
+
+	if (usb3_1) {
+		/* modify bos descriptor bNumDeviceCaps and wTotalLength */
+		buf[4] += 1;
+		put_unaligned_le16(desc_size + ssa_size, &buf[2]);
+	}
+
+	if (wLength < USB_DT_BOS_SIZE + USB_DT_USB_SS_CAP_SIZE)
+		return wLength;
+
+	/* Indicate whether the host has LTM support. */
+	temp = readl(&xhci->cap_regs->hcc_params);
+	if (HCC_LTC(temp))
+		buf[8] |= USB_LTM_SUPPORT;
+
+	/* Set the U1 and U2 exit latencies. */
+	if ((xhci->quirks & XHCI_LPM_SUPPORT)) {
+		temp = readl(&xhci->cap_regs->hcs_params3);
+		buf[12] = HCS_U1_LATENCY(temp);
+		put_unaligned_le16(HCS_U2_LATENCY(temp), &buf[13]);
+	}
+
+	if (usb3_1) {
+		u32 ssp_cap_base, bm_attrib, psi;
+		int offset;
+
+		ssp_cap_base = USB_DT_BOS_SIZE + USB_DT_USB_SS_CAP_SIZE;
+
+		if (wLength < desc_size)
+			return wLength;
+		buf[ssp_cap_base] = ssp_cap_size + ssa_size;
+
+		/* attribute count SSAC bits 4:0 and ID count SSIC bits 8:5 */
+		bm_attrib = (ssa_count - 1) & 0x1f;
+		bm_attrib |= (xhci->usb3_rhub.psi_uid_count - 1) << 5;
+		put_unaligned_le32(bm_attrib, &buf[ssp_cap_base + 4]);
+
+		if (wLength < desc_size + ssa_size)
+			return wLength;
+		/*
+		 * Create the Sublink Speed Attributes (SSA) array.
+		 * The xhci PSI field and USB 3.1 SSA fields are very similar,
+		 * but link type bits 7:6 differ for values 01b and 10b.
+		 * xhci has also only one PSI entry for a symmetric link when
+		 * USB 3.1 requires two SSA entries (RX and TX) for every link
+		 */
+		offset = desc_size;
+		for (i = 0; i < xhci->usb3_rhub.psi_count; i++) {
+			psi = xhci->usb3_rhub.psi[i];
+			psi &= ~USB_SSP_SUBLINK_SPEED_RSVD;
+			if ((psi & PLT_MASK) == PLT_SYM) {
+			/* Symmetric, create SSA RX and TX from one PSI entry */
+				put_unaligned_le32(psi, &buf[offset]);
+				psi |= 1 << 7;  /* turn entry to TX */
+				offset += 4;
+				if (offset >= desc_size + ssa_size)
+					return desc_size + ssa_size;
+			} else if ((psi & PLT_MASK) == PLT_ASYM_RX) {
+				/* Asymetric RX, flip bits 7:6 for SSA */
+				psi ^= PLT_MASK;
+			}
+			put_unaligned_le32(psi, &buf[offset]);
+			offset += 4;
+			if (offset >= desc_size + ssa_size)
+				return desc_size + ssa_size;
+		}
+	}
+	/* ssa_size is 0 for other than usb 3.1 hosts */
+	return desc_size + ssa_size;
+}
 
 static void xhci_common_hub_descriptor(struct xhci_hcd *xhci,
 		struct usb_hub_descriptor *desc, int ports)
@@ -748,25 +849,12 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 		if ((wValue & 0xff00) != (USB_DT_BOS << 8))
 			goto error;
 
-		if (hcd->speed != HCD_USB3)
+		if (hcd->speed < HCD_USB3)
 			goto error;
 
-		/* Set the U1 and U2 exit latencies. */
-		memcpy(buf, &usb_bos_descriptor,
-				USB_DT_BOS_SIZE + USB_DT_USB_SS_CAP_SIZE);
-		if ((xhci->quirks & XHCI_LPM_SUPPORT)) {
-			temp = readl(&xhci->cap_regs->hcs_params3);
-			buf[12] = HCS_U1_LATENCY(temp);
-			put_unaligned_le16(HCS_U2_LATENCY(temp), &buf[13]);
-		}
-
-		/* Indicate whether the host has LTM support. */
-		temp = readl(&xhci->cap_regs->hcc_params);
-		if (HCC_LTC(temp))
-			buf[8] |= USB_LTM_SUPPORT;
-
+		retval = xhci_create_usb3_bos_desc(xhci, buf, wLength);
 		spin_unlock_irqrestore(&xhci->lock, flags);
-		return USB_DT_BOS_SIZE + USB_DT_USB_SS_CAP_SIZE;
+		return retval;
 	case GetPortStatus:
 		if (!wIndex || wIndex > max_ports)
 			goto error;