firewire: fw-ohci: add self ID error check

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@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>

2 files changed, 11 insertions, 4 deletions

diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c
index 92ff38f82d96..1f6f15f0dce2 100644
--- a/drivers/firewire/fw-ohci.c
+++ b/drivers/firewire/fw-ohci.c
@@ -1019,20 +1019,26 @@ static void bus_reset_tasklet(unsigned long data)
         ohci->node_id = reg & (OHCI1394_NodeID_busNumber |
                                OHCI1394_NodeID_nodeNumber);
 
+        reg = reg_read(ohci, OHCI1394_SelfIDCount);
+        if (reg & OHCI1394_SelfIDCount_selfIDError) {
+                fw_notify("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])
-                        fw_error("inconsistent self IDs\n");
+                if (ohci->self_id_cpu[i] != ~ohci->self_id_cpu[i + 1]) {
+                        fw_notify("inconsistent self IDs\n");
+                        return;
+                }
                 ohci->self_id_buffer[j] =
                                 cond_le32_to_cpu(ohci->self_id_cpu[i]);
         }
diff --git a/drivers/firewire/fw-ohci.h b/drivers/firewire/fw-ohci.h
index dec4f04e6b24..5754c6e9d595 100644
--- a/drivers/firewire/fw-ohci.h
+++ b/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