Instead of relying on hard resetting of controller to stop

receiving incoming traffics, try harder to gracefully stop active
DMA cycles and then stop MACs. This is the way what datasheet
recommends and seems to work reliably. Resetting controller while
active DMAs are in progress is bad thing as we can't predict how
DMAs touche allocated TX/RX buffers. This change ensures controller
stop state before attempting to release allocated TX/RX buffers.
Also update MAC statistics which could have been updated during the
wait time of MAC stop.

While I'm here remove unnecessary controller resets in various
location. ste(4) no longer relies on hard controller reset to stop
controller and resetting controller also clears all configured
settings which makes it hard to implement WOL in near future.
Now resetting a controller is performed in ste_init_locked().

1 files changed, 31 insertions, 20 deletions

diff --git a/sys/dev/ste/if_ste.c b/sys/dev/ste/if_ste.c
index 5eec38a..e8ff9ef 100644
--- a/sys/dev/ste/if_ste.c
+++ b/sys/dev/ste/if_ste.c
@@ -651,10 +651,8 @@ ste_poll_locked(struct ifnet *ifp, enum poll_cmd cmd, int count)
 		if (status & STE_ISR_STATS_OFLOW)
 			ste_stats_update(sc);
 
-		if (status & STE_ISR_HOSTERR) {
-			ste_reset(sc);
+		if (status & STE_ISR_HOSTERR)
 			ste_init_locked(sc);
-		}
 	}
 	return (rx_npkts);
 }
@@ -702,10 +700,8 @@ ste_intr(void *xsc)
 		if (status & STE_ISR_STATS_OFLOW)
 			ste_stats_update(sc);
 
-		if (status & STE_ISR_HOSTERR) {
-			ste_reset(sc);
+		if (status & STE_ISR_HOSTERR)
 			ste_init_locked(sc);
-		}
 	}
 
 	/* Re-enable interrupts */
@@ -816,7 +812,6 @@ ste_txeoc(struct ste_softc *sc)
 			device_printf(sc->ste_dev,
 			    "transmission error: %x\n", txstat);
 
-			ste_reset(sc);
 			ste_init_locked(sc);
 
 			if (txstat & STE_TXSTATUS_UNDERRUN &&
@@ -1528,6 +1523,8 @@ ste_init_locked(struct ste_softc *sc)
 	ifp = sc->ste_ifp;
 
 	ste_stop(sc);
+	/* Reset the chip to a known state. */
+	ste_reset(sc);
 
 	/* Init our MAC address */
 	for (i = 0; i < ETHER_ADDR_LEN; i += 2) {
@@ -1633,6 +1630,7 @@ ste_stop(struct ste_softc *sc)
 	struct ifnet *ifp;
 	struct ste_chain_onefrag *cur_rx;
 	struct ste_chain *cur_tx;
+	uint32_t val;
 	int i;
 
 	STE_LOCK_ASSERT(sc);
@@ -1643,19 +1641,33 @@ ste_stop(struct ste_softc *sc)
 	ifp->if_drv_flags &= ~(IFF_DRV_RUNNING|IFF_DRV_OACTIVE);
 
 	CSR_WRITE_2(sc, STE_IMR, 0);
-	STE_SETBIT2(sc, STE_MACCTL1, STE_MACCTL1_TX_DISABLE);
-	STE_SETBIT2(sc, STE_MACCTL1, STE_MACCTL1_RX_DISABLE);
-	STE_SETBIT2(sc, STE_MACCTL1, STE_MACCTL1_STATS_DISABLE);
-	STE_SETBIT2(sc, STE_DMACTL, STE_DMACTL_TXDMA_STALL);
-	STE_SETBIT2(sc, STE_DMACTL, STE_DMACTL_RXDMA_STALL);
+	/* Stop pending DMA. */
+	val = CSR_READ_4(sc, STE_DMACTL);
+	val |= STE_DMACTL_TXDMA_STALL | STE_DMACTL_RXDMA_STALL;
+	CSR_WRITE_4(sc, STE_DMACTL, val);
 	ste_wait(sc);
-	/*
-	 * Try really hard to stop the RX engine or under heavy RX
-	 * data chip will write into de-allocated memory.
-	 */
-	ste_reset(sc);
-
-	sc->ste_flags &= ~STE_FLAG_LINK;
+	/* Disable auto-polling. */
+	CSR_WRITE_1(sc, STE_RX_DMAPOLL_PERIOD, 0);
+	CSR_WRITE_1(sc, STE_TX_DMAPOLL_PERIOD, 0);
+	/* Nullify DMA address to stop any further DMA. */
+	CSR_WRITE_4(sc, STE_RX_DMALIST_PTR, 0);
+	CSR_WRITE_4(sc, STE_TX_DMALIST_PTR, 0);
+	/* Stop TX/RX MAC. */
+	val = CSR_READ_2(sc, STE_MACCTL1);
+	val |= STE_MACCTL1_TX_DISABLE | STE_MACCTL1_RX_DISABLE |
+	    STE_MACCTL1_STATS_DISABLE;
+	CSR_WRITE_2(sc, STE_MACCTL1, val);
+	for (i = 0; i < STE_TIMEOUT; i++) {
+		DELAY(10);
+		if ((CSR_READ_2(sc, STE_MACCTL1) & (STE_MACCTL1_TX_DISABLE |
+		    STE_MACCTL1_RX_DISABLE | STE_MACCTL1_STATS_DISABLE)) == 0)
+			break;
+	}
+	if (i == STE_TIMEOUT)
+		device_printf(sc->ste_dev, "Stopping MAC timed out\n");
+	/* Acknowledge any pending interrupts. */
+	CSR_READ_2(sc, STE_ISR_ACK);
+	ste_stats_update(sc);
 
 	for (i = 0; i < STE_RX_LIST_CNT; i++) {
 		cur_rx = &sc->ste_cdata.ste_rx_chain[i];
@@ -1947,7 +1959,6 @@ ste_watchdog(struct ste_softc *sc)
 	ste_txeoc(sc);
 	ste_txeof(sc);
 	ste_rxeof(sc, -1);
-	ste_reset(sc);
 	ste_init_locked(sc);
 
 	if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))