[PATCH] firewire: fw-ohci: add self ID error check

[Stefan Richter]

Discard self ID buffer contents if
  - the selfIDError flag is set,
  - any of the self ID packets has bit errors.

Signed-off-by: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
---
 drivers/firewire/fw-ohci.c |   12 +++++++++---
 drivers/firewire/fw-ohci.h |    1 +
 2 files changed, 10 insertions(+), 3 deletions(-)

Index: linux/drivers/firewire/fw-ohci.c
===================================================================
--- linux.orig/drivers/firewire/fw-ohci.c
+++ linux/drivers/firewire/fw-ohci.c
@@ -1060,20 +1060,26 @@ static void bus_reset_tasklet(unsigned l
 	ohci->node_id = reg & (OHCI1394_NodeID_busNumber |
 			       OHCI1394_NodeID_nodeNumber);
 
+	reg = reg_read(ohci, OHCI1394_SelfIDCount);
+	if (reg & OHCI1394_SelfIDCount_selfIDError) {
+		fw_error("inconsistent self IDs\n");
+		return;
+	}
 	/*
 	 * The count in the SelfIDCount register is the number of
 	 * bytes in the self ID receive buffer.  Since we also receive
 	 * the inverted quadlets and a header quadlet, we shift one
 	 * bit extra to get the actual number of self IDs.
 	 */
-
-	self_id_count = (reg_read(ohci, OHCI1394_SelfIDCount) >> 3) & 0x3ff;
+	self_id_count = (reg >> 3) & 0x3ff;
 	generation = (cond_le32_to_cpu(ohci->self_id_cpu[0]) >> 16) & 0xff;
 	rmb();
 
 	for (i = 1, j = 0; j < self_id_count; i += 2, j++) {
-		if (ohci->self_id_cpu[i] != ~ohci->self_id_cpu[i + 1])
+		if (ohci->self_id_cpu[i] != ~ohci->self_id_cpu[i + 1]) {
 			fw_error("inconsistent self IDs\n");
+			return;
+		}
 		ohci->self_id_buffer[j] =
 				cond_le32_to_cpu(ohci->self_id_cpu[i]);
 	}
Index: linux/drivers/firewire/fw-ohci.h
===================================================================
--- linux.orig/drivers/firewire/fw-ohci.h
+++ linux/drivers/firewire/fw-ohci.h
@@ -30,6 +30,7 @@
 #define  OHCI1394_HCControl_softReset		0x00010000
 #define OHCI1394_SelfIDBuffer                 0x064
 #define OHCI1394_SelfIDCount                  0x068
+#define  OHCI1394_SelfIDCount_selfIDError	0x80000000
 #define OHCI1394_IRMultiChanMaskHiSet         0x070
 #define OHCI1394_IRMultiChanMaskHiClear       0x074
 #define OHCI1394_IRMultiChanMaskLoSet         0x078

-- 
Stefan Richter
-=====-==--- --== =--==
http://arcgraph.de/sr/

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