xhci: rework xhci extended capability list parsing functions

Replace the existing two extended capability parsing helper functions with
one called xhci_find_next_ext_cap().

The extended capabilities are read both in pci-quirks before xhci driver is
loaded, and inside the xhci driver when adding ports. The existing helpers
did not suit well for these cases and a lot of custom parsing code was
needed.

The new helper function simplifies these two cases a lot.

The motivation for this rework was that code to support xhci debug
capability needed to parse extended capabilities, and it included
yet another capability parsing helper specific for its needs. With
this solution it debug capability code can use this new  helper as well

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

1 files changed, 27 insertions, 46 deletions

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;
-
-		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)
+	offset = cap_start;
+
+	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) {