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cpmac bugfixes and enhancements
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* Resolve some locking issues using atomic_inc/atomic_dec
* move status code in cpmac_check_status
* unmark the BROKEN flag in Kconfig
* move code which should have been in platform code in
  arch/mips/ar7/platform.c
* fixed an IRQ storm which lets the kernel hang
* fixed a double call to netif_start_queue which causes a kernel panic
* don't fail to register the PHY, works on many devices now

Signed-off-by: Matteo Croce <matteo@openwrt.org>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
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Matteo Croce authored and Jeff Garzik committed May 22, 2008
1 parent f47e81f commit f917d58
Showing 1 changed file with 179 additions and 55 deletions.
234 changes: 179 additions & 55 deletions drivers/net/cpmac.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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@imfi.kspu.ru>");
MODULE_DESCRIPTION("TI AR7 ethernet driver (CPMAC)");
Expand Down Expand Up @@ -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;
};
Expand All @@ -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 *);
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand All @@ -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)
Expand All @@ -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;

Expand Down Expand Up @@ -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)
Expand All @@ -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);

Expand All @@ -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)
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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))
Expand All @@ -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);

Expand Down Expand Up @@ -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;
}
}
Expand Down Expand Up @@ -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",
Expand Down

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