bnx2x: Clear dirty status when booting after UNDI

Self-tests following boot from SAN have failed as the
UNDI driver might leave some NIG interrupt indications.

This patch does the clean-up, clearing those indications
and allowing the test to pass.

Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c

@@ -9854,6 +9854,8 @@ static int bnx2x_prev_unload_common(struct bnx2x *bp)
 				prev_undi = true;
 				/* clear the UNDI indication */
 				REG_WR(bp, DORQ_REG_NORM_CID_OFST, 0);
+				/* clear possible idle check errors */
+				REG_RD(bp, NIG_REG_NIG_INT_STS_CLR_0);
 			}
 		}
 		/* wait until BRB is empty */

drivers/net/ethernet/broadcom/bnx2x/bnx2x_reg.h

@@ -2154,6 +2154,8 @@
 /* [R 32] Interrupt register #0 read */
 #define NIG_REG_NIG_INT_STS_0					 0x103b0
 #define NIG_REG_NIG_INT_STS_1					 0x103c0
+/* [RC 32] Interrupt register #0 read clear */
+#define NIG_REG_NIG_INT_STS_CLR_0				 0x103b4
 /* [R 32] Legacy E1 and E1H location for parity error mask register. */
 #define NIG_REG_NIG_PRTY_MASK					 0x103dc
 /* [RW 32] Parity mask register #0 read/write */