tg3: Fix read DMA FIFO overruns on recent devices

Earlier versions of tg3 devices had a problem where the read DMA FIFO
could be overrun in certain edge conditions.  The fix was to limit the
number of rx BDs the hardware would fetch at a time.  For later devices
(5761, 5784 and later ASIC revs), there is a hardware fix that must be
enabled to fix the same problem.  This patch adds that hardware fix.

There is a gap in the ASIC revision lineage where neither fix is
applied.  This is intentional as these ASIC revisions are not afflicted
by the bug.

Reviewed-by: Benjamin Li <benli@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/net/tg3.h b/drivers/net/tg3.h
index 4937bd190964..783cd77b6165 100644
--- a/drivers/net/tg3.h
+++ b/drivers/net/tg3.h
@@ -1302,7 +1302,11 @@
 #define  RDMAC_STATUS_FIFOURUN           0x00000080
 #define  RDMAC_STATUS_FIFOOREAD          0x00000100
 #define  RDMAC_STATUS_LNGREAD            0x00000200
-/* 0x4808 --> 0x4c00 unused */
+/* 0x4808 --> 0x4900 unused */
+
+#define TG3_RDMA_RSRVCTRL_REG           0x00004900
+#define TG3_RDMA_RSRVCTRL_FIFO_OFLW_FIX  0x00000004
+/* 0x4904 --> 0x4c00 unused */
 
 /* Write DMA control registers */
 #define WDMAC_MODE                      0x00004c00