[PATCH 0/4] Calxeda xgmac fixes and performance improvements

[PATCH 0/4] Calxeda xgmac fixes and performance improvements

[Rob Herring]

From: Rob Herring <rob.herring@calxeda.com>

A few fixes and performance improvements for the Calxeda xgmac driver for
3.6. It would be nice to get the 2 fixes into 3.5, but since it is a bit
late in the cycle they can wait.

Rob

Rob Herring (4):
  net: calxedaxgmac: fix net timeout recovery
  net: calxedaxgmac: fix hang on rx refill
  net: calxedaxgmac: set outstanding AXI bus transactions to 8
  net: calxedaxgmac: enable rx cut-thru mode

 drivers/net/ethernet/calxeda/xgmac.c |   35 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 18 deletions(-)

-- 
1.7.9.5

[PATCH 1/4] net: calxedaxgmac: fix net timeout recovery

[Rob Herring]

From: Rob Herring <rob.herring@calxeda.com>

Fix net tx watchdog timeout recovery. The descriptor ring was reset,
but the DMA engine was not reset to the beginning of the ring.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
---
 drivers/net/ethernet/calxeda/xgmac.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/calxeda/xgmac.c b/drivers/net/ethernet/calxeda/xgmac.c
index 11f667f..c4fd2e3 100644
--- a/drivers/net/ethernet/calxeda/xgmac.c
+++ b/drivers/net/ethernet/calxeda/xgmac.c
@@ -933,6 +933,7 @@ static void xgmac_tx_err(struct xgmac_priv *priv)
 	desc_init_tx_desc(priv->dma_tx, DMA_TX_RING_SZ);
 	priv->tx_tail = 0;
 	priv->tx_head = 0;
+	writel(priv->dma_tx_phy, priv->base + XGMAC_DMA_TX_BASE_ADDR);
 	writel(reg | DMA_CONTROL_ST, priv->base + XGMAC_DMA_CONTROL);
 
 	writel(DMA_STATUS_TU | DMA_STATUS_TPS | DMA_STATUS_NIS | DMA_STATUS_AIS,
-- 
1.7.9.5

[PATCH 2/4] net: calxedaxgmac: fix hang on rx refill

[Rob Herring]

From: Rob Herring <rob.herring@calxeda.com>

Fix intermittent hangs in xgmac_rx_refill. If a ring buffer entry already
had an skb allocated, then xgmac_rx_refill would get stuck in a loop. This
can happen on a rx error when we just leave the skb allocated to the entry.

[ 7884.510000] INFO: rcu_preempt detected stall on CPU 0 (t=727315 jiffies)
[ 7884.510000] [<c0010a59>] (unwind_backtrace+0x1/0x98) from [<c006fd93>] (__rcu_pending+0x11b/0x2c4)
[ 7884.510000] [<c006fd93>] (__rcu_pending+0x11b/0x2c4) from [<c0070b95>] (rcu_check_callbacks+0xed/0x1a8)
[ 7884.510000] [<c0070b95>] (rcu_check_callbacks+0xed/0x1a8) from [<c0036abb>] (update_process_times+0x2b/0x48)
[ 7884.510000] [<c0036abb>] (update_process_times+0x2b/0x48) from [<c004e8fd>] (tick_sched_timer+0x51/0x94)
[ 7884.510000] [<c004e8fd>] (tick_sched_timer+0x51/0x94) from [<c0045527>] (__run_hrtimer+0x4f/0x1e8)
[ 7884.510000] [<c0045527>] (__run_hrtimer+0x4f/0x1e8) from [<c0046003>] (hrtimer_interrupt+0xd7/0x1e4)
[ 7884.510000] [<c0046003>] (hrtimer_interrupt+0xd7/0x1e4) from [<c00101d3>] (twd_handler+0x17/0x24)
[ 7884.510000] [<c00101d3>] (twd_handler+0x17/0x24) from [<c006be39>] (handle_percpu_devid_irq+0x59/0x114)
[ 7884.510000] [<c006be39>] (handle_percpu_devid_irq+0x59/0x114) from [<c0069aab>] (generic_handle_irq+0x17/0x2c)
[ 7884.510000] [<c0069aab>] (generic_handle_irq+0x17/0x2c) from [<c000cc8d>] (handle_IRQ+0x35/0x7c)
[ 7884.510000] [<c000cc8d>] (handle_IRQ+0x35/0x7c) from [<c033b153>] (__irq_svc+0x33/0xb8)
[ 7884.510000] [<c033b153>] (__irq_svc+0x33/0xb8) from [<c0244b06>] (xgmac_rx_refill+0x3a/0x140)
[ 7884.510000] [<c0244b06>] (xgmac_rx_refill+0x3a/0x140) from [<c02458ed>] (xgmac_poll+0x265/0x3bc)
[ 7884.510000] [<c02458ed>] (xgmac_poll+0x265/0x3bc) from [<c029fcbf>] (net_rx_action+0xc3/0x200)
[ 7884.510000] [<c029fcbf>] (net_rx_action+0xc3/0x200) from [<c0030cab>] (__do_softirq+0xa3/0x1bc)

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
---
 drivers/net/ethernet/calxeda/xgmac.c |   27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/calxeda/xgmac.c b/drivers/net/ethernet/calxeda/xgmac.c
index c4fd2e3..3ca1d79 100644
--- a/drivers/net/ethernet/calxeda/xgmac.c
+++ b/drivers/net/ethernet/calxeda/xgmac.c
@@ -671,26 +671,23 @@ static void xgmac_rx_refill(struct xgmac_priv *priv)
 
 		p = priv->dma_rx + entry;
 
-		if (priv->rx_skbuff[entry] != NULL)
-			continue;
-
-		skb = __skb_dequeue(&priv->rx_recycle);
-		if (skb == NULL)
-			skb = netdev_alloc_skb(priv->dev, priv->dma_buf_sz);
-		if (unlikely(skb == NULL))
-			break;
-
-		priv->rx_skbuff[entry] = skb;
-		paddr = dma_map_single(priv->device, skb->data,
-					 priv->dma_buf_sz, DMA_FROM_DEVICE);
-		desc_set_buf_addr(p, paddr, priv->dma_buf_sz);
+		if (priv->rx_skbuff[entry] == NULL) {
+			skb = __skb_dequeue(&priv->rx_recycle);
+			if (skb == NULL)
+				skb = netdev_alloc_skb(priv->dev, priv->dma_buf_sz);
+			if (unlikely(skb == NULL))
+				break;
+
+			priv->rx_skbuff[entry] = skb;
+			paddr = dma_map_single(priv->device, skb->data,
+					       priv->dma_buf_sz, DMA_FROM_DEVICE);
+			desc_set_buf_addr(p, paddr, priv->dma_buf_sz);
+		}
 
 		netdev_dbg(priv->dev, "rx ring: head %d, tail %d\n",
 			priv->rx_head, priv->rx_tail);
 
 		priv->rx_head = dma_ring_incr(priv->rx_head, DMA_RX_RING_SZ);
-		/* Ensure descriptor is in memory before handing to h/w */
-		wmb();
 		desc_set_rx_owner(p);
 	}
 }
-- 
1.7.9.5

[PATCH 3/4] net: calxedaxgmac: set outstanding AXI bus transactions to 8

[Rob Herring]

From: Rob Herring <rob.herring@calxeda.com>

Increase the number of outstanding read and write AXI transactions from 1
to 8 for better performance.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
---
 drivers/net/ethernet/calxeda/xgmac.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/calxeda/xgmac.c b/drivers/net/ethernet/calxeda/xgmac.c
index 3ca1d79..abb8f40 100644
--- a/drivers/net/ethernet/calxeda/xgmac.c
+++ b/drivers/net/ethernet/calxeda/xgmac.c
@@ -970,7 +970,7 @@ static int xgmac_hw_init(struct net_device *dev)
 	writel(DMA_INTR_DEFAULT_MASK, ioaddr + XGMAC_DMA_INTR_ENA);
 
 	/* XGMAC requires AXI bus init. This is a 'magic number' for now */
-	writel(0x000100E, ioaddr + XGMAC_DMA_AXI_BUS);
+	writel(0x0077000E, ioaddr + XGMAC_DMA_AXI_BUS);
 
 	ctrl |= XGMAC_CONTROL_DDIC | XGMAC_CONTROL_JE | XGMAC_CONTROL_ACS |
 		XGMAC_CONTROL_CAR;
-- 
1.7.9.5

[PATCH 4/4] net: calxedaxgmac: enable rx cut-thru mode

[Rob Herring]

From: Rob Herring <rob.herring@calxeda.com>

Enabling RX cut-thru mode yields better performance as received frames
start getting written to memory before a whole frame is received.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
---
 drivers/net/ethernet/calxeda/xgmac.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/calxeda/xgmac.c b/drivers/net/ethernet/calxeda/xgmac.c
index abb8f40..2b4b4f5 100644
--- a/drivers/net/ethernet/calxeda/xgmac.c
+++ b/drivers/net/ethernet/calxeda/xgmac.c
@@ -264,7 +264,7 @@
 #define XGMAC_OMR_FEF		0x00000080	/* Forward Error Frames */
 #define XGMAC_OMR_DT		0x00000040	/* Drop TCP/IP csum Errors */
 #define XGMAC_OMR_RSF		0x00000020	/* RX FIFO Store and Forward */
-#define XGMAC_OMR_RTC		0x00000010	/* RX Threshhold Ctrl */
+#define XGMAC_OMR_RTC_256	0x00000018	/* RX Threshhold Ctrl */
 #define XGMAC_OMR_RTC_MASK	0x00000018	/* RX Threshhold Ctrl MASK */
 
 /* XGMAC HW Features Register */
@@ -982,7 +982,8 @@ static int xgmac_hw_init(struct net_device *dev)
 	writel(value, ioaddr + XGMAC_DMA_CONTROL);
 
 	/* Set the HW DMA mode and the COE */
-	writel(XGMAC_OMR_TSF | XGMAC_OMR_RSF | XGMAC_OMR_RFD | XGMAC_OMR_RFA,
+	writel(XGMAC_OMR_TSF | XGMAC_OMR_RFD | XGMAC_OMR_RFA |
+		XGMAC_OMR_RTC_256,
 		ioaddr + XGMAC_OMR);
 
 	/* Reset the MMC counters */
-- 
1.7.9.5

Re: [PATCH 0/4] Calxeda xgmac fixes and performance improvements

[David Miller]

From: Rob Herring <robherring2@gmail.com>
Date: Mon,  9 Jul 2012 19:16:06 -0500

> From: Rob Herring <rob.herring@calxeda.com>
> 
> A few fixes and performance improvements for the Calxeda xgmac driver for
> 3.6. It would be nice to get the 2 fixes into 3.5, but since it is a bit
> late in the cycle they can wait.

All applied to net-nex, thanks.