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Date: Fri, 26 Apr 2013 10:52:09 +0200
From: Lucas Stach <l.stach@...gutronix.de>
To: "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Cc: David Miller <davem@...emloft.net>,
Frank Li <Frank.Li@...escale.com>,
Fabio Estevam <festevam@...il.com>,
Shawn Guo <shawn.guo@...aro.org>,
Lucas Stach <l.stach@...gutronix.de>
Subject: [PATCH resend 2/3] Revert "net: fec: put tx to napi poll function to fix dead lock"
This reverts commit de5fb0a053482d89262c3284b67884cd2c621adc.
This commit changed how ringbuffers are tracked. I suspect this
to break in subtle ways, which I unfortunately wasn't able to track
down to a single-line change.
Also in preparation to revert the initial NAPI introduction commit.
Signed-off-by: Lucas Stach <l.stach@...gutronix.de>
---
drivers/net/ethernet/freescale/fec.c | 86 ++++++++++++++++++------------------
drivers/net/ethernet/freescale/fec.h | 3 ++
2 files changed, 47 insertions(+), 42 deletions(-)
diff --git a/drivers/net/ethernet/freescale/fec.c b/drivers/net/ethernet/freescale/fec.c
index afb52eb..fa6a999 100644
--- a/drivers/net/ethernet/freescale/fec.c
+++ b/drivers/net/ethernet/freescale/fec.c
@@ -246,13 +246,14 @@ fec_enet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
struct bufdesc *bdp;
void *bufaddr;
unsigned short status;
- unsigned int index;
+ unsigned long flags;
if (!fep->link) {
/* Link is down or autonegotiation is in progress. */
return NETDEV_TX_BUSY;
}
+ spin_lock_irqsave(&fep->hw_lock, flags);
/* Fill in a Tx ring entry */
bdp = fep->cur_tx;
@@ -263,6 +264,7 @@ fec_enet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
* This should not happen, since ndev->tbusy should be set.
*/
printk("%s: tx queue full!.\n", ndev->name);
+ spin_unlock_irqrestore(&fep->hw_lock, flags);
return NETDEV_TX_BUSY;
}
@@ -278,13 +280,13 @@ fec_enet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
* 4-byte boundaries. Use bounce buffers to copy data
* and get it aligned. Ugh.
*/
- if (fep->bufdesc_ex)
- index = (struct bufdesc_ex *)bdp -
- (struct bufdesc_ex *)fep->tx_bd_base;
- else
- index = bdp - fep->tx_bd_base;
-
if (((unsigned long) bufaddr) & FEC_ALIGNMENT) {
+ unsigned int index;
+ if (fep->bufdesc_ex)
+ index = (struct bufdesc_ex *)bdp -
+ (struct bufdesc_ex *)fep->tx_bd_base;
+ else
+ index = bdp - fep->tx_bd_base;
memcpy(fep->tx_bounce[index], skb->data, skb->len);
bufaddr = fep->tx_bounce[index];
}
@@ -298,7 +300,10 @@ fec_enet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
swap_buffer(bufaddr, skb->len);
/* Save skb pointer */
- fep->tx_skbuff[index] = skb;
+ fep->tx_skbuff[fep->skb_cur] = skb;
+
+ ndev->stats.tx_bytes += skb->len;
+ fep->skb_cur = (fep->skb_cur+1) & TX_RING_MOD_MASK;
/* Push the data cache so the CPM does not get stale memory
* data.
@@ -326,22 +331,26 @@ fec_enet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
ebdp->cbd_esc = BD_ENET_TX_INT;
}
}
+ /* Trigger transmission start */
+ writel(0, fep->hwp + FEC_X_DES_ACTIVE);
+
/* If this was the last BD in the ring, start at the beginning again. */
if (status & BD_ENET_TX_WRAP)
bdp = fep->tx_bd_base;
else
bdp = fec_enet_get_nextdesc(bdp, fep->bufdesc_ex);
- fep->cur_tx = bdp;
-
- if (fep->cur_tx == fep->dirty_tx)
+ if (bdp == fep->dirty_tx) {
+ fep->tx_full = 1;
netif_stop_queue(ndev);
+ }
- /* Trigger transmission start */
- writel(0, fep->hwp + FEC_X_DES_ACTIVE);
+ fep->cur_tx = bdp;
skb_tx_timestamp(skb);
+ spin_unlock_irqrestore(&fep->hw_lock, flags);
+
return NETDEV_TX_OK;
}
@@ -373,7 +382,7 @@ static void fec_enet_bd_init(struct net_device *dev)
/* ...and the same for transmit */
bdp = fep->tx_bd_base;
- fep->cur_tx = bdp;
+ fep->dirty_tx = fep->cur_tx = bdp;
for (i = 0; i < TX_RING_SIZE; i++) {
/* Initialize the BD for every fragment in the page. */
@@ -389,7 +398,6 @@ static void fec_enet_bd_init(struct net_device *dev)
/* Set the last buffer to wrap */
bdp = fec_enet_get_prevdesc(bdp, fep->bufdesc_ex);
bdp->cbd_sc |= BD_SC_WRAP;
- fep->dirty_tx = bdp;
}
/* This function is called to start or restart the FEC during a link
@@ -446,7 +454,8 @@ fec_restart(struct net_device *ndev, int duplex)
writel((unsigned long)fep->bd_dma + sizeof(struct bufdesc)
* RX_RING_SIZE, fep->hwp + FEC_X_DES_START);
-
+ /* Reset SKB transmit buffers. */
+ fep->skb_cur = fep->skb_dirty = 0;
for (i = 0; i <= TX_RING_MOD_MASK; i++) {
if (fep->tx_skbuff[i]) {
dev_kfree_skb_any(fep->tx_skbuff[i]);
@@ -609,35 +618,20 @@ fec_enet_tx(struct net_device *ndev)
struct bufdesc *bdp;
unsigned short status;
struct sk_buff *skb;
- int index = 0;
fep = netdev_priv(ndev);
+ spin_lock(&fep->hw_lock);
bdp = fep->dirty_tx;
- /* get next bdp of dirty_tx */
- if (bdp->cbd_sc & BD_ENET_TX_WRAP)
- bdp = fep->tx_bd_base;
- else
- bdp = fec_enet_get_nextdesc(bdp, fep->bufdesc_ex);
-
while (((status = bdp->cbd_sc) & BD_ENET_TX_READY) == 0) {
-
- /* current queue is empty */
- if (bdp == fep->cur_tx)
+ if (bdp == fep->cur_tx && fep->tx_full == 0)
break;
- if (fep->bufdesc_ex)
- index = (struct bufdesc_ex *)bdp -
- (struct bufdesc_ex *)fep->tx_bd_base;
- else
- index = bdp - fep->tx_bd_base;
-
dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr,
FEC_ENET_TX_FRSIZE, DMA_TO_DEVICE);
bdp->cbd_bufaddr = 0;
- skb = fep->tx_skbuff[index];
-
+ skb = fep->tx_skbuff[fep->skb_dirty];
/* Check for errors. */
if (status & (BD_ENET_TX_HB | BD_ENET_TX_LC |
BD_ENET_TX_RL | BD_ENET_TX_UN |
@@ -682,9 +676,8 @@ fec_enet_tx(struct net_device *ndev)
/* Free the sk buffer associated with this last transmit */
dev_kfree_skb_any(skb);
- fep->tx_skbuff[index] = NULL;
-
- fep->dirty_tx = bdp;
+ fep->tx_skbuff[fep->skb_dirty] = NULL;
+ fep->skb_dirty = (fep->skb_dirty + 1) & TX_RING_MOD_MASK;
/* Update pointer to next buffer descriptor to be transmitted */
if (status & BD_ENET_TX_WRAP)
@@ -694,12 +687,14 @@ fec_enet_tx(struct net_device *ndev)
/* Since we have freed up a buffer, the ring is no longer full
*/
- if (fep->dirty_tx != fep->cur_tx) {
+ if (fep->tx_full) {
+ fep->tx_full = 0;
if (netif_queue_stopped(ndev))
netif_wake_queue(ndev);
}
}
- return;
+ fep->dirty_tx = bdp;
+ spin_unlock(&fep->hw_lock);
}
@@ -866,7 +861,7 @@ fec_enet_interrupt(int irq, void *dev_id)
int_events = readl(fep->hwp + FEC_IEVENT);
writel(int_events, fep->hwp + FEC_IEVENT);
- if (int_events & (FEC_ENET_RXF | FEC_ENET_TXF)) {
+ if (int_events & FEC_ENET_RXF) {
ret = IRQ_HANDLED;
/* Disable the RX interrupt */
@@ -877,6 +872,15 @@ fec_enet_interrupt(int irq, void *dev_id)
}
}
+ /* Transmit OK, or non-fatal error. Update the buffer
+ * descriptors. FEC handles all errors, we just discover
+ * them as part of the transmit process.
+ */
+ if (int_events & FEC_ENET_TXF) {
+ ret = IRQ_HANDLED;
+ fec_enet_tx(ndev);
+ }
+
if (int_events & FEC_ENET_MII) {
ret = IRQ_HANDLED;
complete(&fep->mdio_done);
@@ -892,8 +896,6 @@ static int fec_enet_rx_napi(struct napi_struct *napi, int budget)
int pkts = fec_enet_rx(ndev, budget);
struct fec_enet_private *fep = netdev_priv(ndev);
- fec_enet_tx(ndev);
-
if (pkts < budget) {
napi_complete(napi);
writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index eb43729..b70c3cd 100644
--- a/drivers/net/ethernet/freescale/fec.h
+++ b/drivers/net/ethernet/freescale/fec.h
@@ -213,6 +213,8 @@ struct fec_enet_private {
unsigned char *tx_bounce[TX_RING_SIZE];
struct sk_buff *tx_skbuff[TX_RING_SIZE];
struct sk_buff *rx_skbuff[RX_RING_SIZE];
+ ushort skb_cur;
+ ushort skb_dirty;
/* CPM dual port RAM relative addresses */
dma_addr_t bd_dma;
@@ -224,6 +226,7 @@ struct fec_enet_private {
/* The ring entries to be free()ed */
struct bufdesc *dirty_tx;
+ uint tx_full;
/* hold while accessing the HW like ringbuffer for tx/rx but not MAC */
spinlock_t hw_lock;
--
1.8.2.rc2
--
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