diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
index f9400564cb72..26cb8c861e6e 100644
--- a/drivers/usb/host/pci-quirks.c
+++ b/drivers/usb/host/pci-quirks.c
@@ -984,24 +984,17 @@ static void quirk_usb_handoff_xhci(struct pci_dev *pdev)
 	 * Find the Legacy Support Capability register -
 	 * this is optional for xHCI host controllers.
 	 */
-	ext_cap_offset = xhci_find_next_cap_offset(base, XHCI_HCC_PARAMS_OFFSET);
-	do {
-		if ((ext_cap_offset + sizeof(val)) > len) {
-			/* We're reading garbage from the controller */
-			dev_warn(&pdev->dev,
-				 "xHCI controller failing to respond");
-			return;
-		}
+	ext_cap_offset = xhci_find_next_ext_cap(base, 0, XHCI_EXT_CAPS_LEGACY);
 
-		if (!ext_cap_offset)
-			/* We've reached the end of the extended capabilities */
-			goto hc_init;
+	if (!ext_cap_offset)
+		goto hc_init;
 
-		val = readl(base + ext_cap_offset);
-		if (XHCI_EXT_CAPS_ID(val) == XHCI_EXT_CAPS_LEGACY)
-			break;
-		ext_cap_offset = xhci_find_next_cap_offset(base, ext_cap_offset);
-	} while (1);
+	if ((ext_cap_offset + sizeof(val)) > len) {
+		/* We're reading garbage from the controller */
+		dev_warn(&pdev->dev, "xHCI controller failing to respond");
+		return;
+	}
+	val = readl(base + ext_cap_offset);
 
 	/* If the BIOS owns the HC, signal that the OS wants it, and wait */
 	if (val & XHCI_HC_BIOS_OWNED) {
diff --git a/drivers/usb/host/xhci-ext-caps.h b/drivers/usb/host/xhci-ext-caps.h
index 9fe3225e6c61..04ce6b156b35 100644
--- a/drivers/usb/host/xhci-ext-caps.h
+++ b/drivers/usb/host/xhci-ext-caps.h
@@ -90,67 +90,40 @@
 
 #include <linux/io.h>
 
-/**
- * Return the next extended capability pointer register.
- *
- * @base	PCI register base address.
- *
- * @ext_offset	Offset of the 32-bit register that contains the extended
- * capabilites pointer.  If searching for the first extended capability, pass
- * in XHCI_HCC_PARAMS_OFFSET.  If searching for the next extended capability,
- * pass in the offset of the current extended capability register.
- *
- * Returns 0 if there is no next extended capability register or returns the register offset
- * from the PCI registers base address.
- */
-static inline int xhci_find_next_cap_offset(void __iomem *base, int ext_offset)
-{
-	u32 next;
-
-	next = readl(base + ext_offset);
-
-	if (ext_offset == XHCI_HCC_PARAMS_OFFSET) {
-		/* Find the first extended capability */
-		next = XHCI_HCC_EXT_CAPS(next);
-		ext_offset = 0;
-	} else {
-		/* Find the next extended capability */
-		next = XHCI_EXT_CAPS_NEXT(next);
-	}
-
-	if (!next)
-		return 0;
-	/*
-	 * Address calculation from offset of extended capabilities
-	 * (or HCCPARAMS) register - see section 5.3.6 and section 7.
-	 */
-	return ext_offset + (next << 2);
-}
-
 /**
  * Find the offset of the extended capabilities with capability ID id.
  *
- * @base PCI MMIO registers base address.
- * @ext_offset Offset from base of the first extended capability to look at,
- * 		or the address of HCCPARAMS.
- * @id Extended capability ID to search for.
+ * @base	PCI MMIO registers base address.
+ * @start	address at which to start looking, (0 or HCC_PARAMS to start at
+ *		beginning of list)
+ * @id		Extended capability ID to search for.
  *
- * This uses an arbitrary limit of XHCI_MAX_EXT_CAPS extended capabilities
- * to make sure that the list doesn't contain a loop.
+ * Returns the offset of the next matching extended capability structure.
+ * Some capabilities can occur several times, e.g., the XHCI_EXT_CAPS_PROTOCOL,
+ * and this provides a way to find them all.
  */
-static inline int xhci_find_ext_cap_by_id(void __iomem *base, int ext_offset, int id)
+
+static inline int xhci_find_next_ext_cap(void __iomem *base, u32 start, int id)
 {
 	u32 val;
-	int limit = XHCI_MAX_EXT_CAPS;
+	u32 next;
+	u32 offset;
+
+	offset = start;
+	if (!start || start == XHCI_HCC_PARAMS_OFFSET) {
+		val = readl(base + XHCI_HCC_PARAMS_OFFSET);
+		offset = XHCI_HCC_EXT_CAPS(val) << 2;
+		if (!offset)
+			return 0;
+	};
+	do {
+		val = readl(base + offset);
+		if (XHCI_EXT_CAPS_ID(val) == id && offset != start)
+			return offset;
+
+		next = XHCI_EXT_CAPS_NEXT(val);
+		offset += next << 2;
+	} while (next);
 
-	while (ext_offset && limit > 0) {
-		val = readl(base + ext_offset);
-		if (XHCI_EXT_CAPS_ID(val) == id)
-			break;
-		ext_offset = xhci_find_next_cap_offset(base, ext_offset);
-		limit--;
-	}
-	if (limit > 0)
-		return ext_offset;
 	return 0;
 }
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 536d00f21eed..dc7f915d9a13 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2064,17 +2064,19 @@ static void xhci_set_hc_event_deq(struct xhci_hcd *xhci)
 }
 
 static void xhci_add_in_port(struct xhci_hcd *xhci, unsigned int num_ports,
-		__le32 __iomem *addr, u8 major_revision, int max_caps)
+		__le32 __iomem *addr, int max_caps)
 {
 	u32 temp, port_offset, port_count;
 	int i;
+	u8 major_revision;
 	struct xhci_hub *rhub;
 
 	temp = readl(addr);
+	major_revision = XHCI_EXT_PORT_MAJOR(temp);
 
-	if (XHCI_EXT_PORT_MAJOR(temp) == 0x03) {
+	if (major_revision == 0x03) {
 		rhub = &xhci->usb3_rhub;
-	} else if (XHCI_EXT_PORT_MAJOR(temp) <= 0x02) {
+	} else if (major_revision <= 0x02) {
 		rhub = &xhci->usb2_rhub;
 	} else {
 		xhci_warn(xhci, "Ignoring unknown port speed, "
@@ -2190,19 +2192,12 @@ static void xhci_add_in_port(struct xhci_hcd *xhci, unsigned int num_ports,
  */
 static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
 {
-	__le32 __iomem *addr, *tmp_addr;
-	u32 offset, tmp_offset;
+	void __iomem *base;
+	u32 offset;
 	unsigned int num_ports;
 	int i, j, port_index;
 	int cap_count = 0;
-
-	addr = &xhci->cap_regs->hcc_params;
-	offset = XHCI_HCC_EXT_CAPS(readl(addr));
-	if (offset == 0) {
-		xhci_err(xhci, "No Extended Capability registers, "
-				"unable to set up roothub.\n");
-		return -ENODEV;
-	}
+	u32 cap_start;
 
 	num_ports = HCS_MAX_PORTS(xhci->hcs_params1);
 	xhci->port_array = kzalloc(sizeof(*xhci->port_array)*num_ports, flags);
@@ -2220,48 +2215,34 @@ static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
 		for (j = 0; j < XHCI_MAX_INTERVAL; j++)
 			INIT_LIST_HEAD(&bw_table->interval_bw[j].endpoints);
 	}
+	base = &xhci->cap_regs->hc_capbase;
 
-	/*
-	 * For whatever reason, the first capability offset is from the
-	 * capability register base, not from the HCCPARAMS register.
-	 * See section 5.3.6 for offset calculation.
-	 */
-	addr = &xhci->cap_regs->hc_capbase + offset;
-
-	tmp_addr = addr;
-	tmp_offset = offset;
+	cap_start = xhci_find_next_ext_cap(base, 0, XHCI_EXT_CAPS_PROTOCOL);
+	if (!cap_start) {
+		xhci_err(xhci, "No Extended Capability registers, unable to set up roothub\n");
+		return -ENODEV;
+	}
 
+	offset = cap_start;
 	/* count extended protocol capability entries for later caching */
-	do {
-		u32 cap_id;
-		cap_id = readl(tmp_addr);
-		if (XHCI_EXT_CAPS_ID(cap_id) == XHCI_EXT_CAPS_PROTOCOL)
-			cap_count++;
-		tmp_offset = XHCI_EXT_CAPS_NEXT(cap_id);
-		tmp_addr += tmp_offset;
-	} while (tmp_offset);
+	while (offset) {
+		cap_count++;
+		offset = xhci_find_next_ext_cap(base, offset,
+						      XHCI_EXT_CAPS_PROTOCOL);
+	}
 
 	xhci->ext_caps = kzalloc(sizeof(*xhci->ext_caps) * cap_count, flags);
 	if (!xhci->ext_caps)
 		return -ENOMEM;
 
-	while (1) {
-		u32 cap_id;
+	offset = cap_start;
 
-		cap_id = readl(addr);
-		if (XHCI_EXT_CAPS_ID(cap_id) == XHCI_EXT_CAPS_PROTOCOL)
-			xhci_add_in_port(xhci, num_ports, addr,
-					(u8) XHCI_EXT_PORT_MAJOR(cap_id),
-					cap_count);
-		offset = XHCI_EXT_CAPS_NEXT(cap_id);
-		if (!offset || (xhci->num_usb2_ports + xhci->num_usb3_ports)
-				== num_ports)
+	while (offset) {
+		xhci_add_in_port(xhci, num_ports, base + offset, cap_count);
+		if (xhci->num_usb2_ports + xhci->num_usb3_ports == num_ports)
 			break;
-		/*
-		 * Once you're into the Extended Capabilities, the offset is
-		 * always relative to the register holding the offset.
-		 */
-		addr += offset;
+		offset = xhci_find_next_ext_cap(base, offset,
+						XHCI_EXT_CAPS_PROTOCOL);
 	}
 
 	if (xhci->num_usb2_ports == 0 && xhci->num_usb3_ports == 0) {