UHCI: improved debugging checks for the frame list

This patch (as768) improves the debugging checks for the uhci-hcd
frame list.  The number of entries displayed is limited to 10, and the
driver now checks for the correct Skeleton QH link value at the end of
each chain of Isochronous TDs.  The code to compute these link values
is now used in two spots, so it is moved into its own separate
subroutine.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 43 insertions, 5 deletions

diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c
index e345f15b7d87..b40bc1ac9b8c 100644
--- a/drivers/usb/host/uhci-debug.c
+++ b/drivers/usb/host/uhci-debug.c
@@ -347,6 +347,7 @@ static int uhci_sprint_schedule(struct uhci_hcd *uhci, char *buf, int len)
 	struct uhci_qh *qh;
 	struct uhci_td *td;
 	struct list_head *tmp, *head;
+	int nframes, nerrs;
 
 	out += uhci_show_root_hub_state(uhci, out, len - (out - buf));
 	out += sprintf(out, "HC status\n");
@@ -355,23 +356,60 @@ static int uhci_sprint_schedule(struct uhci_hcd *uhci, char *buf, int len)
 		return out - buf;
 
 	out += sprintf(out, "Frame List\n");
+	nframes = 10;
+	nerrs = 0;
 	for (i = 0; i < UHCI_NUMFRAMES; ++i) {
+		__le32 link, qh_dma;
+
+		j = 0;
 		td = uhci->frame_cpu[i];
+		link = uhci->frame[i];
 		if (!td)
-			continue;
+			goto check_link;
 
-		out += sprintf(out, "- Frame %d\n", i); \
-		if (td->dma_handle != (dma_addr_t)uhci->frame[i])
-			out += sprintf(out, "    frame list does not match td->dma_handle!\n");
+		if (nframes > 0) {
+			out += sprintf(out, "- Frame %d -> (%08x)\n",
+					i, le32_to_cpu(link));
+			j = 1;
+		}
 
 		head = &td->fl_list;
 		tmp = head;
 		do {
 			td = list_entry(tmp, struct uhci_td, fl_list);
 			tmp = tmp->next;
-			out += uhci_show_td(td, out, len - (out - buf), 4);
+			if (cpu_to_le32(td->dma_handle) != link) {
+				if (nframes > 0)
+					out += sprintf(out, "    link does "
+						"not match list entry!\n");
+				else
+					++nerrs;
+			}
+			if (nframes > 0)
+				out += uhci_show_td(td, out,
+						len - (out - buf), 4);
+			link = td->link;
 		} while (tmp != head);
+
+check_link:
+		qh_dma = uhci_frame_skel_link(uhci, i);
+		if (link != qh_dma) {
+			if (nframes > 0) {
+				if (!j) {
+					out += sprintf(out,
+						"- Frame %d -> (%08x)\n",
+						i, le32_to_cpu(link));
+					j = 1;
+				}
+				out += sprintf(out, "   link does not match "
+					"QH (%08x)!\n", le32_to_cpu(qh_dma));
+			} else
+				++nerrs;
+		}
+		nframes -= j;
 	}
+	if (nerrs > 0)
+		out += sprintf(out, "Skipped %d bad links\n", nerrs);
 
 	out += sprintf(out, "Skeleton QHs\n");