Handle all TX errors, not only underruns.
Reinitialize the TX ring after skipping all remaining frames, and
restart the controller when everything has been cleaned up properly.
Original idea from a patch by Havard Skinnemoen.
Signed-off-by: Nicolas Ferre <nicolas.fe...@atmel.com>
---
drivers/net/ethernet/cadence/macb.c | 124 ++++++++++++++++++++---------------
1 file changed, 71 insertions(+), 53 deletions(-)
diff --git a/drivers/net/ethernet/cadence/macb.c
b/drivers/net/ethernet/cadence/macb.c
index 3d3a077..af71151 100644
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -44,6 +44,10 @@
#define MACB_RX_INT_FLAGS (MACB_BIT(RCOMP) | MACB_BIT(RXUBR) \
| MACB_BIT(ISR_ROVR))
+#define MACB_TX_INT_FLAGS (MACB_BIT(ISR_TUND) \
+ | MACB_BIT(ISR_RLE) \
+ | MACB_BIT(TXERR) \
+ | MACB_BIT(TCOMP))
/* Ring buffer accessors */
static unsigned int macb_tx_ring_wrap(unsigned int index)
@@ -338,66 +342,56 @@ static void macb_update_stats(struct macb *bp)
*p += __raw_readl(reg);
}
-static void macb_tx(struct macb *bp)
+static void macb_handle_tx_error(struct macb *bp, unsigned int err_tail, u32
ctrl)
{
- unsigned int tail;
- unsigned int head;
- u32 status;
-
- status = macb_readl(bp, TSR);
- macb_writel(bp, TSR, status);
+ struct macb_tx_skb *tx_skb;
+ struct sk_buff *skb;
+ unsigned int head = bp->tx_head;
- netdev_vdbg(bp->dev, "macb_tx status = %02lx\n", (unsigned long)status);
+ netdev_dbg(bp->dev, "TX error: ctrl 0x%08x, head %u, error tail %u\n",
+ ctrl, head, err_tail);
- if (status & (MACB_BIT(UND) | MACB_BIT(TSR_RLE))) {
- int i;
- netdev_err(bp->dev, "TX %s, resetting buffers\n",
- status & MACB_BIT(UND) ?
- "underrun" : "retry limit exceeded");
-
- /* Transfer ongoing, disable transmitter, to avoid confusion */
- if (status & MACB_BIT(TGO))
- macb_writel(bp, NCR, macb_readl(bp, NCR) &
~MACB_BIT(TE));
-
- head = bp->tx_head;
-
- /*Mark all the buffer as used to avoid sending a lost buffer*/
- for (i = 0; i < TX_RING_SIZE; i++)
- bp->tx_ring[i].ctrl = MACB_BIT(TX_USED);
-
- /* Add wrap bit */
- bp->tx_ring[TX_RING_SIZE - 1].ctrl |= MACB_BIT(TX_WRAP);
+ /*
+ * "Buffers exhausted mid-frame" errors may only happen if the
+ * driver is buggy, so complain loudly about those. Statistics
+ * are updated by hardware.
+ */
+ if (ctrl & MACB_BIT(TX_BUF_EXHAUSTED))
+ netdev_err(bp->dev, "BUG: TX buffers exhausted mid-frame\n");
- /* free transmit buffer in upper layer*/
- for (tail = bp->tx_tail; tail != head; tail++) {
- struct macb_tx_skb *tx_skb;
- struct sk_buff *skb;
+ /*
+ * Drop the frames that caused the error plus all remaining in queue.
+ * Free transmit buffers in upper layer.
+ */
+ for (; err_tail != head; err_tail++) {
+ struct macb_dma_desc *desc;
- rmb();
+ tx_skb = macb_tx_skb(bp, err_tail);
+ skb = tx_skb->skb;
+ dma_unmap_single(&bp->pdev->dev, tx_skb->mapping, skb->len,
+ DMA_TO_DEVICE);
+ dev_kfree_skb_irq(skb);
+ tx_skb->skb = NULL;
- tx_skb = macb_tx_skb(bp, tail);
- skb = tx_skb->skb;
+ desc = macb_tx_desc(bp, err_tail);
+ desc->ctrl |= MACB_BIT(TX_USED);
+ }
- dma_unmap_single(&bp->pdev->dev, tx_skb->mapping,
- skb->len, DMA_TO_DEVICE);
- tx_skb->skb = NULL;
- dev_kfree_skb_irq(skb);
- }
+ /* Make descriptor updates visible to hardware */
+ wmb();
+}
- bp->tx_head = bp->tx_tail = 0;
+static void macb_tx_interrupt(struct macb *bp)
+{
+ unsigned int tail;
+ unsigned int head;
+ u32 status;
- /* Enable the transmitter again */
- if (status & MACB_BIT(TGO))
- macb_writel(bp, NCR, macb_readl(bp, NCR) |
MACB_BIT(TE));
- }
+ status = macb_readl(bp, TSR);
+ macb_writel(bp, TSR, status);
- if (!(status & MACB_BIT(COMP)))
- /*
- * This may happen when a buffer becomes complete
- * between reading the ISR and scanning the
- * descriptors. Nothing to worry about.
- */
- return;
+ netdev_vdbg(bp->dev, "macb_tx_interrupt status = %02lx\n",
+ (unsigned long)status);
head = bp->tx_head;
for (tail = bp->tx_tail; tail != head; tail++) {
@@ -413,6 +407,31 @@ static void macb_tx(struct macb *bp)
ctrl = desc->ctrl;
+ if (unlikely(ctrl & (MACB_BIT(TX_ERROR)
+ | MACB_BIT(TX_UNDERRUN)
+ | MACB_BIT(TX_BUF_EXHAUSTED)))) {
+ /*
+ * In case of transfer ongoing, disable transmitter.
+ * Should already be the case due to hardware,
+ * but make sure to avoid confusion.
+ */
+ if (status & MACB_BIT(TGO))
+ macb_writel(bp, NCR, macb_readl(bp, NCR) &
~MACB_BIT(TE));
+
+ /*
+ * An error should always stop the queue from advancing.
+ * reset entries in the ring and exit from the loop.
+ */
+ macb_handle_tx_error(bp, tail, ctrl);
+ bp->tx_head = bp->tx_tail = head = tail = 0;
+
+ /* Enable the transmitter again, start TX will be done
elsewhere */
+ if (status & MACB_BIT(TGO))
+ macb_writel(bp, NCR, macb_readl(bp, NCR) |
MACB_BIT(TE));
+
+ break;
+ }
+
if (!(ctrl & MACB_BIT(TX_USED)))
break;
@@ -644,9 +663,8 @@ static irqreturn_t macb_interrupt(int irq, void *dev_id)
}
}
- if (status & (MACB_BIT(TCOMP) | MACB_BIT(ISR_TUND) |
- MACB_BIT(ISR_RLE)))
- macb_tx(bp);
+ if (status & MACB_TX_INT_FLAGS)
+ macb_tx_interrupt(bp);
/*
* Link change detection isn't possible with RMII, so we'll
--
1.7.10
--
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