Il Tuesday 06 May 2008 01:16:34 Andrew Morton ha scritto:
> On Sun, 4 May 2008 19:04:22 +0200
> Matteo Croce <matteo@xxxxxxxxxxx> wrote:
>
> > This patch fixes an IRQ storm, a locking issues, moves platform code in the right sections
> > and other small fixes.
> >
>
> Please feed this patch (and all future ones) through scripts/checkpatch.pl.
> It picks up rather a lot of simple problems which there is no reason for
> us to retain.
>
> >
> > ...
> >
> > + spin_unlock(&priv->rx_lock);
> > + netif_rx_complete(priv->dev, napi);
> > + netif_stop_queue(priv->dev);
> > + napi_disable(&priv->napi);
> > +
> > + atomic_inc(&priv->reset_pending);
> > + cpmac_hw_stop(priv->dev);
> > + if (!schedule_work(&priv->reset_work))
> > + atomic_dec(&priv->reset_pending);
> > + return 0;
> > +
> > }
> >
> > static int cpmac_start_xmit(struct sk_buff *skb, struct net_device *dev)
> > @@ -456,6 +549,9 @@ static int cpmac_start_xmit(struct sk_buff *skb, struct net_device *dev)
> > struct cpmac_desc *desc;
> > struct cpmac_priv *priv = netdev_priv(dev);
> >
> > + if (unlikely(atomic_read(&priv->reset_pending)))
> > + return NETDEV_TX_BUSY;
> > +
>
> This looks a bit strange. schedule_work() will return zero if the work was
> already scheduled, in which case we arrange for cpmac_start_xmit() to abort
> early.
>
> But if schedule_work() *doesn't* return zero, there is a time window in
> which the reset is still pending. Because it takes time for keventd to be
> awoken and to run the work function.
>
> I would have thought that we would want to prevent cpmac_start_xmit() from
> running within that time window also?
>
>
> But that's just a guess - the text which you used to describe your work is
> missing much information, so I don't have a lot to work with here.
>
This one is cleaner:
Signed-off-by: Matteo Croce <matteo@xxxxxxxxxxx>
Signed-off-by: Felix Fietkau <nbd@xxxxxxxxxxx>
diff --git a/drivers/net/cpmac.c b/drivers/net/cpmac.c
index 2b5740b..7f3f62e 100644
--- a/drivers/net/cpmac.c
+++ b/drivers/net/cpmac.c
@@ -38,6 +38,7 @@
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <asm/gpio.h>
+#include <asm/atomic.h>
MODULE_AUTHOR("Eugene Konev <ejka@xxxxxxxxxxxx>");
MODULE_DESCRIPTION("TI AR7 ethernet driver (CPMAC)");
@@ -187,6 +188,7 @@ struct cpmac_desc {
#define CPMAC_EOQ 0x1000
struct sk_buff *skb;
struct cpmac_desc *next;
+ struct cpmac_desc *prev;
dma_addr_t mapping;
dma_addr_t data_mapping;
};
@@ -208,6 +210,7 @@ struct cpmac_priv {
struct work_struct reset_work;
struct platform_device *pdev;
struct napi_struct napi;
+ atomic_t reset_pending;
};
static irqreturn_t cpmac_irq(int, void *);
@@ -241,6 +244,16 @@ static void cpmac_dump_desc(struct net_device *dev, struct cpmac_desc *desc)
printk("\n");
}
+static void cpmac_dump_all_desc(struct net_device *dev)
+{
+ struct cpmac_priv *priv = netdev_priv(dev);
+ struct cpmac_desc *dump = priv->rx_head;
+ do {
+ cpmac_dump_desc(dev, dump);
+ dump = dump->next;
+ } while (dump != priv->rx_head);
+}
+
static void cpmac_dump_skb(struct net_device *dev, struct sk_buff *skb)
{
int i;
@@ -412,21 +425,42 @@ static struct sk_buff *cpmac_rx_one(struct cpmac_priv *priv,
static int cpmac_poll(struct napi_struct *napi, int budget)
{
struct sk_buff *skb;
- struct cpmac_desc *desc;
- int received = 0;
+ struct cpmac_desc *desc, *restart;
struct cpmac_priv *priv = container_of(napi, struct cpmac_priv, napi);
+ int received = 0, processed = 0;
spin_lock(&priv->rx_lock);
if (unlikely(!priv->rx_head)) {
if (netif_msg_rx_err(priv) && net_ratelimit())
printk(KERN_WARNING "%s: rx: polling, but no queue\n",
priv->dev->name);
+ spin_unlock(&priv->rx_lock);
netif_rx_complete(priv->dev, napi);
return 0;
}
desc = priv->rx_head;
+ restart = NULL;
while (((desc->dataflags & CPMAC_OWN) == 0) && (received < budget)) {
+ processed++;
+
+ if ((desc->dataflags & CPMAC_EOQ) != 0) {
+ /* The last update to eoq->hw_next didn't happen
+ * soon enough, and the receiver stopped here.
+ *Remember this descriptor so we can restart
+ * the receiver after freeing some space.
+ */
+ if (unlikely(restart)) {
+ if (netif_msg_rx_err(priv))
+ printk(KERN_ERR "%s: poll found a"
+ " duplicate EOQ: %p and %p\n",
+ priv->dev->name, restart, desc);
+ goto fatal_error;
+ }
+
+ restart = desc->next;
+ }
+
skb = cpmac_rx_one(priv, desc);
if (likely(skb)) {
netif_receive_skb(skb);
@@ -435,19 +469,90 @@ static int cpmac_poll(struct napi_struct *napi, int budget)
desc = desc->next;
}
+ if (desc != priv->rx_head) {
+ /* We freed some buffers, but not the whole ring,
+ * add what we did free to the rx list */
+ desc->prev->hw_next = (u32)0;
+ priv->rx_head->prev->hw_next = priv->rx_head->mapping;
+ }
+
+ /* Optimization: If we did not actually process an EOQ (perhaps because
+ * of quota limits), check to see if the tail of the queue has EOQ set.
+ * We should immediately restart in that case so that the receiver can
+ * restart and run in parallel with more packet processing.
+ * This lets us handle slightly larger bursts before running
+ * out of ring space (assuming dev->weight < ring_size) */
+
+ if (!restart &&
+ (priv->rx_head->prev->dataflags & (CPMAC_OWN|CPMAC_EOQ))
+ == CPMAC_EOQ &&
+ (priv->rx_head->dataflags & CPMAC_OWN) != 0) {
+ /* reset EOQ so the poll loop (above) doesn't try to
+ * restart this when it eventually gets to this descriptor.
+ */
+ priv->rx_head->prev->dataflags &= ~CPMAC_EOQ;
+ restart = priv->rx_head;
+ }
+
+ if (restart) {
+ priv->dev->stats.rx_errors++;
+ priv->dev->stats.rx_fifo_errors++;
+ if (netif_msg_rx_err(priv) && net_ratelimit())
+ printk(KERN_WARNING "%s: rx dma ring overrun\n",
+ priv->dev->name);
+
+ if (unlikely((restart->dataflags & CPMAC_OWN) == 0)) {
+ if (netif_msg_drv(priv))
+ printk(KERN_ERR "%s: cpmac_poll is trying to "
+ "restart rx from a descriptor that's "
+ "not free: %p\n",
+ priv->dev->name, restart);
+ goto fatal_error;
+ }
+
+ cpmac_write(priv->regs, CPMAC_RX_PTR(0), restart->mapping);
+ }
+
priv->rx_head = desc;
spin_unlock(&priv->rx_lock);
if (unlikely(netif_msg_rx_status(priv)))
printk(KERN_DEBUG "%s: poll processed %d packets\n",
priv->dev->name, received);
- if (desc->dataflags & CPMAC_OWN) {
+ if (processed == 0) {
+ /* we ran out of packets to read,
+ * revert to interrupt-driven mode */
netif_rx_complete(priv->dev, napi);
- cpmac_write(priv->regs, CPMAC_RX_PTR(0), (u32)desc->mapping);
cpmac_write(priv->regs, CPMAC_RX_INT_ENABLE, 1);
return 0;
}
return 1;
+
+fatal_error:
+ /* Something went horribly wrong.
+ * Reset hardware to try to recover rather than wedging. */
+
+ if (netif_msg_drv(priv)) {
+ printk(KERN_ERR "%s: cpmac_poll is confused. "
+ "Resetting hardware\n", priv->dev->name);
+ cpmac_dump_all_desc(priv->dev);
+ printk(KERN_DEBUG "%s: RX_PTR(0)=0x%08x RX_ACK(0)=0x%08x\n",
+ priv->dev->name,
+ cpmac_read(priv->regs, CPMAC_RX_PTR(0)),
+ cpmac_read(priv->regs, CPMAC_RX_ACK(0)));
+ }
+
+ spin_unlock(&priv->rx_lock);
+ netif_rx_complete(priv->dev, napi);
+ netif_stop_queue(priv->dev);
+ napi_disable(&priv->napi);
+
+ atomic_inc(&priv->reset_pending);
+ cpmac_hw_stop(priv->dev);
+ if (!schedule_work(&priv->reset_work))
+ atomic_dec(&priv->reset_pending);
+ return 0;
+
}
static int cpmac_start_xmit(struct sk_buff *skb, struct net_device *dev)
@@ -456,6 +561,9 @@ static int cpmac_start_xmit(struct sk_buff *skb, struct net_device *dev)
struct cpmac_desc *desc;
struct cpmac_priv *priv = netdev_priv(dev);
+ if (unlikely(atomic_read(&priv->reset_pending)))
+ return NETDEV_TX_BUSY;
+
if (unlikely(skb_padto(skb, ETH_ZLEN)))
return NETDEV_TX_OK;
@@ -621,8 +729,10 @@ static void cpmac_clear_rx(struct net_device *dev)
desc->dataflags = CPMAC_OWN;
dev->stats.rx_dropped++;
}
+ desc->hw_next = desc->next->mapping;
desc = desc->next;
}
+ priv->rx_head->prev->hw_next = 0;
}
static void cpmac_clear_tx(struct net_device *dev)
@@ -635,14 +745,14 @@ static void cpmac_clear_tx(struct net_device *dev)
priv->desc_ring[i].dataflags = 0;
if (priv->desc_ring[i].skb) {
dev_kfree_skb_any(priv->desc_ring[i].skb);
- if (netif_subqueue_stopped(dev, i))
- netif_wake_subqueue(dev, i);
+ priv->desc_ring[i].skb = NULL;
}
}
}
static void cpmac_hw_error(struct work_struct *work)
{
+ int i;
struct cpmac_priv *priv =
container_of(work, struct cpmac_priv, reset_work);
@@ -651,8 +761,48 @@ static void cpmac_hw_error(struct work_struct *work)
spin_unlock(&priv->rx_lock);
cpmac_clear_tx(priv->dev);
cpmac_hw_start(priv->dev);
- napi_enable(&priv->napi);
- netif_start_queue(priv->dev);
+ barrier();
+ atomic_dec(&priv->reset_pending);
+
+ for (i = 0; i < CPMAC_QUEUES; i++)
+ netif_wake_subqueue(priv->dev, i);
+ netif_wake_queue(priv->dev);
+ cpmac_write(priv->regs, CPMAC_MAC_INT_ENABLE, 3);
+}
+
+static void cpmac_check_status(struct net_device *dev)
+{
+ struct cpmac_priv *priv = netdev_priv(dev);
+
+ u32 macstatus = cpmac_read(priv->regs, CPMAC_MAC_STATUS);
+ int rx_channel = (macstatus >> 8) & 7;
+ int rx_code = (macstatus >> 12) & 15;
+ int tx_channel = (macstatus >> 16) & 7;
+ int tx_code = (macstatus >> 20) & 15;
+
+ if (rx_code || tx_code) {
+ if (netif_msg_drv(priv) && net_ratelimit()) {
+ /* Can't find any documentation on what these
+ *error codes actually are. So just log them and hope..
+ */
+ if (rx_code)
+ printk(KERN_WARNING "%s: host error %d on rx "
+ "channel %d (macstatus %08x), resetting\n",
+ dev->name, rx_code, rx_channel, macstatus);
+ if (tx_code)
+ printk(KERN_WARNING "%s: host error %d on tx "
+ "channel %d (macstatus %08x), resetting\n",
+ dev->name, tx_code, tx_channel, macstatus);
+ }
+
+ netif_stop_queue(dev);
+ cpmac_hw_stop(dev);
+ if (schedule_work(&priv->reset_work))
+ atomic_inc(&priv->reset_pending);
+ if (unlikely(netif_msg_hw(priv)))
+ cpmac_dump_regs(dev);
+ }
+ cpmac_write(priv->regs, CPMAC_MAC_INT_CLEAR, 0xff);
}
static irqreturn_t cpmac_irq(int irq, void *dev_id)
@@ -683,49 +833,32 @@ static irqreturn_t cpmac_irq(int irq, void *dev_id)
cpmac_write(priv->regs, CPMAC_MAC_EOI_VECTOR, 0);
- if (unlikely(status & (MAC_INT_HOST | MAC_INT_STATUS))) {
- if (netif_msg_drv(priv) && net_ratelimit())
- printk(KERN_ERR "%s: hw error, resetting...\n",
- dev->name);
- netif_stop_queue(dev);
- napi_disable(&priv->napi);
- cpmac_hw_stop(dev);
- schedule_work(&priv->reset_work);
- if (unlikely(netif_msg_hw(priv)))
- cpmac_dump_regs(dev);
- }
+ if (unlikely(status & (MAC_INT_HOST | MAC_INT_STATUS)))
+ cpmac_check_status(dev);
return IRQ_HANDLED;
}
static void cpmac_tx_timeout(struct net_device *dev)
{
- struct cpmac_priv *priv = netdev_priv(dev);
int i;
+ struct cpmac_priv *priv = netdev_priv(dev);
spin_lock(&priv->lock);
dev->stats.tx_errors++;
spin_unlock(&priv->lock);
if (netif_msg_tx_err(priv) && net_ratelimit())
printk(KERN_WARNING "%s: transmit timeout\n", dev->name);
- /*
- * FIXME: waking up random queue is not the best thing to
- * do... on the other hand why we got here at all?
- */
-#ifdef CONFIG_NETDEVICES_MULTIQUEUE
+
+ atomic_inc(&priv->reset_pending);
+ barrier();
+ cpmac_clear_tx(dev);
+ barrier();
+ atomic_dec(&priv->reset_pending);
+
+ netif_wake_queue(priv->dev);
for (i = 0; i < CPMAC_QUEUES; i++)
- if (priv->desc_ring[i].skb) {
- priv->desc_ring[i].dataflags = 0;
- dev_kfree_skb_any(priv->desc_ring[i].skb);
- netif_wake_subqueue(dev, i);
- break;
- }
-#else
- priv->desc_ring[0].dataflags = 0;
- if (priv->desc_ring[0].skb)
- dev_kfree_skb_any(priv->desc_ring[0].skb);
- netif_wake_queue(dev);
-#endif
+ netif_wake_subqueue(dev, i);
}
static int cpmac_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
@@ -901,9 +1034,12 @@ static int cpmac_open(struct net_device *dev)
desc->buflen = CPMAC_SKB_SIZE;
desc->dataflags = CPMAC_OWN;
desc->next = &priv->rx_head[(i + 1) % priv->ring_size];
+ desc->next->prev = desc;
desc->hw_next = (u32)desc->next->mapping;
}
+ priv->rx_head->prev->hw_next = (u32)0;
+
if ((res = request_irq(dev->irq, cpmac_irq, IRQF_SHARED,
dev->name, dev))) {
if (netif_msg_drv(priv))
@@ -912,6 +1048,7 @@ static int cpmac_open(struct net_device *dev)
goto fail_irq;
}
+ atomic_set(&priv->reset_pending, 0);
INIT_WORK(&priv->reset_work, cpmac_hw_error);
cpmac_hw_start(dev);
@@ -1007,21 +1144,10 @@ static int __devinit cpmac_probe(struct platform_device *pdev)
if (phy_id == PHY_MAX_ADDR) {
if (external_switch || dumb_switch) {
- struct fixed_phy_status status = {};
-
- /*
- * FIXME: this should be in the platform code!
- * Since there is not platform code at all (that is,
- * no mainline users of that driver), place it here
- * for now.
- */
- phy_id = 0;
- status.link = 1;
- status.duplex = 1;
- status.speed = 100;
- fixed_phy_add(PHY_POLL, phy_id, &status);
+ mdio_bus_id = 0; /* fixed phys bus */
+ phy_id = pdev->id;
} else {
- printk(KERN_ERR "cpmac: no PHY present\n");
+ dev_err(&pdev->dev, "no PHY present\n");
return -ENODEV;
}
}
@@ -1064,10 +1190,8 @@ static int __devinit cpmac_probe(struct platform_device *pdev)
priv->msg_enable = netif_msg_init(debug_level, 0xff);
memcpy(dev->dev_addr, pdata->dev_addr, sizeof(dev->dev_addr));
- snprintf(priv->phy_name, BUS_ID_SIZE, PHY_ID_FMT, mdio_bus_id, phy_id);
-
- priv->phy = phy_connect(dev, priv->phy_name, &cpmac_adjust_link, 0,
- PHY_INTERFACE_MODE_MII);
+ priv->phy = phy_connect(dev, cpmac_mii.phy_map[phy_id]->dev.bus_id,
+ &cpmac_adjust_link, 0, PHY_INTERFACE_MODE_MII);
if (IS_ERR(priv->phy)) {
if (netif_msg_drv(priv))
printk(KERN_ERR "%s: Could not attach to PHY\n",
