Add workaround for Yukon FE+ A0. This controller is known to have

severe silicon bugs that can't handle VLAN hardware tagging as well
as status LE writeback bug. The status LE writeback bug is so
critical we can't trust status word of received frame. To accept
frames on Yukon FE+ A0 msk(4) just do minimal check for received
frames and pass them to upper stack. This means msk(4) can pass
corrupted frames to upper layer. You have been warned!
Also I supposed RX_GMF_FL_THR to be 32bits register but Linux
driver treated it as 16bit register so follow their leads. At least
this does not seem to break msk(4) on Yukon FE+.

Tested by:	bz, Tanguy Bouzeloc ( the.zauron <> gmail dot com )
		Bruce Cran ( bruce <> cran dot org dot uk )
		Michael Reifenberger ( mike <> reifenberger dot com )
		Stephen Montgomery-Smith ( stephen <> missouri dot edu )

2 files changed, 52 insertions, 11 deletions

diff --git a/sys/dev/msk/if_msk.c b/sys/dev/msk/if_msk.c
index 81dfa06..c3e3e4a 100644
--- a/sys/dev/msk/if_msk.c
+++ b/sys/dev/msk/if_msk.c
@@ -1493,14 +1493,17 @@ msk_attach(device_t dev)
 	ether_ifattach(ifp, eaddr);
 	MSK_IF_LOCK(sc_if);
 
-	/*
-	 * VLAN capability setup 
-	 * Due to Tx checksum offload hardware bugs, msk(4) manually
-	 * computes checksum for short frames. For VLAN tagged frames
-	 * this workaround does not work so disable checksum offload
-	 * for VLAN interface.
-	 */
-	ifp->if_capabilities |= IFCAP_VLAN_MTU | IFCAP_VLAN_HWTAGGING;
+	/* VLAN capability setup */
+	ifp->if_capabilities |= IFCAP_VLAN_MTU;
+	if ((sc_if->msk_flags & MSK_FLAG_NOHWVLAN) == 0) {
+		/*
+		 * Due to Tx checksum offload hardware bugs, msk(4) manually
+		 * computes checksum for short frames. For VLAN tagged frames
+		 * this workaround does not work so disable checksum offload
+		 * for VLAN interface.
+		 */
+        	ifp->if_capabilities |= IFCAP_VLAN_HWTAGGING;
+	}
 	ifp->if_capenable = ifp->if_capabilities;
 
 	/*
@@ -1646,6 +1649,19 @@ mskc_attach(device_t dev)
 	case CHIP_ID_YUKON_FE_P:
 		sc->msk_clock = 50;	/* 50 Mhz */
 		sc->msk_pflags |= MSK_FLAG_FASTETHER | MSK_FLAG_DESCV2;
+		if (sc->msk_hw_rev == CHIP_REV_YU_FE_P_A0) {
+			/*
+			 * XXX
+			 * FE+ A0 has status LE writeback bug so msk(4)
+			 * does not rely on status word of received frame
+			 * in msk_rxeof() which in turn disables all
+			 * hardware assistance bits reported by the status
+			 * word as well as validity of the recevied frame.
+			 * Just pass received frames to upper stack with
+			 * minimal test and let upper stack handle them.
+			 */
+			sc->msk_pflags |= MSK_FLAG_NOHWVLAN | MSK_FLAG_NORXCHK;
+		}
 		break;
 	case CHIP_ID_YUKON_XL:
 		sc->msk_clock = 156;	/* 156 Mhz */
@@ -2882,7 +2898,18 @@ msk_rxeof(struct msk_if_softc *sc_if, uint32_t status, int len)
 		if ((status & GMR_FS_VLAN) != 0 &&
 		    (ifp->if_capenable & IFCAP_VLAN_HWTAGGING) != 0)
 			rxlen -= ETHER_VLAN_ENCAP_LEN;
-		if (len > sc_if->msk_framesize ||
+		if ((sc_if->msk_flags & MSK_FLAG_NORXCHK) != 0) {
+			/*
+			 * For controllers that returns bogus status code
+			 * just do minimal check and let upper stack
+			 * handle this frame.
+			 */
+			if (len > MSK_MAX_FRAMELEN || len < ETHER_HDR_LEN) {
+				ifp->if_ierrors++;
+				msk_discard_rxbuf(sc_if, cons);
+				break;
+			}
+		} else if (len > sc_if->msk_framesize ||
 		    ((status & GMR_FS_ANY_ERR) != 0) ||
 		    ((status & GMR_FS_RX_OK) == 0) || (rxlen != len)) {
 			/* Don't count flow-control packet as errors. */
@@ -3613,8 +3640,12 @@ msk_init_locked(struct msk_if_softc *sc_if)
 	 * Set Rx FIFO flush threshold to 64 bytes + 1 FIFO word
 	 * due to hardware hang on receipt of pause frames.
 	 */
-	CSR_WRITE_4(sc, MR_ADDR(sc_if->msk_port, RX_GMF_FL_THR),
-	    RX_GMF_FL_THR_DEF + 1);
+	reg = RX_GMF_FL_THR_DEF + 1;
+	/* Another magic for Yukon FE+ - From Linux. */
+	if (sc->msk_hw_id == CHIP_ID_YUKON_FE_P &&
+	    sc->msk_hw_rev == CHIP_REV_YU_FE_P_A0)
+		reg = 0x178;
+	CSR_WRITE_2(sc, MR_ADDR(sc_if->msk_port, RX_GMF_FL_THR), reg);
 
 	/* Configure Tx MAC FIFO. */
 	CSR_WRITE_4(sc, MR_ADDR(sc_if->msk_port, TX_GMF_CTRL_T), GMF_RST_SET);
@@ -3646,6 +3677,14 @@ msk_init_locked(struct msk_if_softc *sc_if)
 		}
 	}
 
+ 	if (sc->msk_hw_id == CHIP_ID_YUKON_FE_P &&
+ 	    sc->msk_hw_rev == CHIP_REV_YU_FE_P_A0) {
+ 		/* Disable dynamic watermark - from Linux. */
+ 		reg = CSR_READ_4(sc, MR_ADDR(sc_if->msk_port, TX_GMF_EA));
+ 		reg &= ~0x03;
+ 		CSR_WRITE_4(sc, MR_ADDR(sc_if->msk_port, TX_GMF_EA), reg);
+ 	}
+
 	/*
 	 * Disable Force Sync bit and Alloc bit in Tx RAM interface
 	 * arbiter as we don't use Sync Tx queue.
diff --git a/sys/dev/msk/if_mskreg.h b/sys/dev/msk/if_mskreg.h
index c4d9030..d979419 100644
--- a/sys/dev/msk/if_mskreg.h
+++ b/sys/dev/msk/if_mskreg.h
@@ -2396,6 +2396,8 @@ struct msk_if_softc {
 #define	MSK_FLAG_JUMBO_NOCSUM	0x0010
 #define	MSK_FLAG_RAMBUF		0x0020
 #define	MSK_FLAG_DESCV2		0x0040
+#define	MSK_FLAG_NOHWVLAN	0x0080
+#define	MSK_FLAG_NORXCHK	0x0100
 #define	MSK_FLAG_SUSPEND	0x2000
 #define	MSK_FLAG_DETACH		0x4000
 #define	MSK_FLAG_LINK		0x8000