1 files changed, 32 insertions, 55 deletions

diff --git a/drivers/usb/host/xhci-ext-caps.h b/drivers/usb/host/xhci-ext-caps.h
index 9fe3225e6c61..e0244fb3903d 100644
--- a/drivers/usb/host/xhci-ext-caps.h
+++ b/drivers/usb/host/xhci-ext-caps.h
@@ -91,66 +91,43 @@
 #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;
-
-	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;
+	u32 next;
+	u32 offset;
+
+	offset = start;
+	if (!start || start == XHCI_HCC_PARAMS_OFFSET) {
+		val = readl(base + XHCI_HCC_PARAMS_OFFSET);
+		if (val == ~0)
+			return 0;
+		offset = XHCI_HCC_EXT_CAPS(val) << 2;
+		if (!offset)
+			return 0;
+	};
+	do {
+		val = readl(base + offset);
+		if (val == ~0)
+			return 0;
+		if (XHCI_EXT_CAPS_ID(val) == id && offset != start)
+			return offset;
+
+		next = XHCI_EXT_CAPS_NEXT(val);
+		offset += next << 2;
+	} while (next);
+
 	return 0;
 }