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[PATCH] natsemi: NAPI and a bugfix
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This patch converts the natsemi driver to use NAPI.  It was originally
based on one written by Harald Welte, though it has since been modified
quite a bit, most extensively in order to remove the ability to disable
NAPI since none of the other drivers seem to provide that functionality
any more.

Signed-off-by: Mark Brown <broonie@sirena.org.uk>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
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Mark Brown authored and Jeff Garzik committed Mar 4, 2006
1 parent fb15b9d commit b27a16b
Showing 1 changed file with 97 additions and 49 deletions.
146 changes: 97 additions & 49 deletions drivers/net/natsemi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@
Written/copyright 1999-2001 by Donald Becker.
Portions copyright (c) 2001,2002 Sun Microsystems (thockin@sun.com)
Portions copyright 2001,2002 Manfred Spraul (manfred@colorfullife.com)
Portions copyright 2004 Harald Welte <laforge@gnumonks.org>
This software may be used and distributed according to the terms of
the GNU General Public License (GPL), incorporated herein by reference.
Expand Down Expand Up @@ -135,8 +136,6 @@
TODO:
* big endian support with CFG:BEM instead of cpu_to_le32
* support for an external PHY
* NAPI
*/

#include <linux/config.h>
Expand All @@ -160,6 +159,7 @@
#include <linux/mii.h>
#include <linux/crc32.h>
#include <linux/bitops.h>
#include <linux/prefetch.h>
#include <asm/processor.h> /* Processor type for cache alignment. */
#include <asm/io.h>
#include <asm/irq.h>
Expand All @@ -183,8 +183,6 @@
NETIF_MSG_TX_ERR)
static int debug = -1;

/* Maximum events (Rx packets, etc.) to handle at each interrupt. */
static int max_interrupt_work = 20;
static int mtu;

/* Maximum number of multicast addresses to filter (vs. rx-all-multicast).
Expand Down Expand Up @@ -251,14 +249,11 @@ MODULE_AUTHOR("Donald Becker <becker@scyld.com>");
MODULE_DESCRIPTION("National Semiconductor DP8381x series PCI Ethernet driver");
MODULE_LICENSE("GPL");

module_param(max_interrupt_work, int, 0);
module_param(mtu, int, 0);
module_param(debug, int, 0);
module_param(rx_copybreak, int, 0);
module_param_array(options, int, NULL, 0);
module_param_array(full_duplex, int, NULL, 0);
MODULE_PARM_DESC(max_interrupt_work,
"DP8381x maximum events handled per interrupt");
MODULE_PARM_DESC(mtu, "DP8381x MTU (all boards)");
MODULE_PARM_DESC(debug, "DP8381x default debug level");
MODULE_PARM_DESC(rx_copybreak,
Expand Down Expand Up @@ -691,6 +686,8 @@ struct netdev_private {
/* Based on MTU+slack. */
unsigned int rx_buf_sz;
int oom;
/* Interrupt status */
u32 intr_status;
/* Do not touch the nic registers */
int hands_off;
/* external phy that is used: only valid if dev->if_port != PORT_TP */
Expand Down Expand Up @@ -748,7 +745,8 @@ static void init_registers(struct net_device *dev);
static int start_tx(struct sk_buff *skb, struct net_device *dev);
static irqreturn_t intr_handler(int irq, void *dev_instance, struct pt_regs *regs);
static void netdev_error(struct net_device *dev, int intr_status);
static void netdev_rx(struct net_device *dev);
static int natsemi_poll(struct net_device *dev, int *budget);
static void netdev_rx(struct net_device *dev, int *work_done, int work_to_do);
static void netdev_tx_done(struct net_device *dev);
static int natsemi_change_mtu(struct net_device *dev, int new_mtu);
#ifdef CONFIG_NET_POLL_CONTROLLER
Expand Down Expand Up @@ -776,6 +774,18 @@ static inline void __iomem *ns_ioaddr(struct net_device *dev)
return (void __iomem *) dev->base_addr;
}

static inline void natsemi_irq_enable(struct net_device *dev)
{
writel(1, ns_ioaddr(dev) + IntrEnable);
readl(ns_ioaddr(dev) + IntrEnable);
}

static inline void natsemi_irq_disable(struct net_device *dev)
{
writel(0, ns_ioaddr(dev) + IntrEnable);
readl(ns_ioaddr(dev) + IntrEnable);
}

static void move_int_phy(struct net_device *dev, int addr)
{
struct netdev_private *np = netdev_priv(dev);
Expand Down Expand Up @@ -879,6 +889,7 @@ static int __devinit natsemi_probe1 (struct pci_dev *pdev,
spin_lock_init(&np->lock);
np->msg_enable = (debug >= 0) ? (1<<debug)-1 : NATSEMI_DEF_MSG;
np->hands_off = 0;
np->intr_status = 0;

/* Initial port:
* - If the nic was configured to use an external phy and if find_mii
Expand Down Expand Up @@ -932,6 +943,9 @@ static int __devinit natsemi_probe1 (struct pci_dev *pdev,
dev->do_ioctl = &netdev_ioctl;
dev->tx_timeout = &tx_timeout;
dev->watchdog_timeo = TX_TIMEOUT;
dev->poll = natsemi_poll;
dev->weight = 64;

#ifdef CONFIG_NET_POLL_CONTROLLER
dev->poll_controller = &natsemi_poll_controller;
#endif
Expand Down Expand Up @@ -2158,68 +2172,92 @@ static void netdev_tx_done(struct net_device *dev)
}
}

/* The interrupt handler does all of the Rx thread work and cleans up
after the Tx thread. */
/* The interrupt handler doesn't actually handle interrupts itself, it
* schedules a NAPI poll if there is anything to do. */
static irqreturn_t intr_handler(int irq, void *dev_instance, struct pt_regs *rgs)
{
struct net_device *dev = dev_instance;
struct netdev_private *np = netdev_priv(dev);
void __iomem * ioaddr = ns_ioaddr(dev);
int boguscnt = max_interrupt_work;
unsigned int handled = 0;

if (np->hands_off)
return IRQ_NONE;
do {
/* Reading automatically acknowledges all int sources. */
u32 intr_status = readl(ioaddr + IntrStatus);

/* Reading automatically acknowledges. */
np->intr_status = readl(ioaddr + IntrStatus);

if (netif_msg_intr(np))
printk(KERN_DEBUG
"%s: Interrupt, status %#08x, mask %#08x.\n",
dev->name, intr_status,
readl(ioaddr + IntrMask));
if (netif_msg_intr(np))
printk(KERN_DEBUG
"%s: Interrupt, status %#08x, mask %#08x.\n",
dev->name, np->intr_status,
readl(ioaddr + IntrMask));

if (intr_status == 0)
break;
handled = 1;
if (!np->intr_status)
return IRQ_NONE;

if (intr_status &
(IntrRxDone | IntrRxIntr | RxStatusFIFOOver |
IntrRxErr | IntrRxOverrun)) {
netdev_rx(dev);
}
prefetch(&np->rx_skbuff[np->cur_rx % RX_RING_SIZE]);

if (netif_rx_schedule_prep(dev)) {
/* Disable interrupts and register for poll */
natsemi_irq_disable(dev);
__netif_rx_schedule(dev);
}
return IRQ_HANDLED;
}

/* This is the NAPI poll routine. As well as the standard RX handling
* it also handles all other interrupts that the chip might raise.
*/
static int natsemi_poll(struct net_device *dev, int *budget)
{
struct netdev_private *np = netdev_priv(dev);
void __iomem * ioaddr = ns_ioaddr(dev);

if (intr_status &
(IntrTxDone | IntrTxIntr | IntrTxIdle | IntrTxErr)) {
int work_to_do = min(*budget, dev->quota);
int work_done = 0;

do {
if (np->intr_status &
(IntrTxDone | IntrTxIntr | IntrTxIdle | IntrTxErr)) {
spin_lock(&np->lock);
netdev_tx_done(dev);
spin_unlock(&np->lock);
}

/* Abnormal error summary/uncommon events handlers. */
if (intr_status & IntrAbnormalSummary)
netdev_error(dev, intr_status);

if (--boguscnt < 0) {
if (netif_msg_intr(np))
printk(KERN_WARNING
"%s: Too much work at interrupt, "
"status=%#08x.\n",
dev->name, intr_status);
break;
if (np->intr_status & IntrAbnormalSummary)
netdev_error(dev, np->intr_status);

if (np->intr_status &
(IntrRxDone | IntrRxIntr | RxStatusFIFOOver |
IntrRxErr | IntrRxOverrun)) {
netdev_rx(dev, &work_done, work_to_do);
}
} while (1);

*budget -= work_done;
dev->quota -= work_done;

if (netif_msg_intr(np))
printk(KERN_DEBUG "%s: exiting interrupt.\n", dev->name);
if (work_done >= work_to_do)
return 1;

np->intr_status = readl(ioaddr + IntrStatus);
} while (np->intr_status);

return IRQ_RETVAL(handled);
netif_rx_complete(dev);

/* Reenable interrupts providing nothing is trying to shut
* the chip down. */
spin_lock(&np->lock);
if (!np->hands_off && netif_running(dev))
natsemi_irq_enable(dev);
spin_unlock(&np->lock);

return 0;
}

/* This routine is logically part of the interrupt handler, but separated
for clarity and better register allocation. */
static void netdev_rx(struct net_device *dev)
static void netdev_rx(struct net_device *dev, int *work_done, int work_to_do)
{
struct netdev_private *np = netdev_priv(dev);
int entry = np->cur_rx % RX_RING_SIZE;
Expand All @@ -2237,6 +2275,12 @@ static void netdev_rx(struct net_device *dev)
entry, desc_status);
if (--boguscnt < 0)
break;

if (*work_done >= work_to_do)
break;

(*work_done)++;

pkt_len = (desc_status & DescSizeMask) - 4;
if ((desc_status&(DescMore|DescPktOK|DescRxLong)) != DescPktOK){
if (desc_status & DescMore) {
Expand Down Expand Up @@ -2293,7 +2337,7 @@ static void netdev_rx(struct net_device *dev)
np->rx_skbuff[entry] = NULL;
}
skb->protocol = eth_type_trans(skb, dev);
netif_rx(skb);
netif_receive_skb(skb);
dev->last_rx = jiffies;
np->stats.rx_packets++;
np->stats.rx_bytes += pkt_len;
Expand Down Expand Up @@ -3074,9 +3118,7 @@ static int netdev_close(struct net_device *dev)
del_timer_sync(&np->timer);
disable_irq(dev->irq);
spin_lock_irq(&np->lock);
/* Disable interrupts, and flush posted writes */
writel(0, ioaddr + IntrEnable);
readl(ioaddr + IntrEnable);
natsemi_irq_disable(dev);
np->hands_off = 1;
spin_unlock_irq(&np->lock);
enable_irq(dev->irq);
Expand Down Expand Up @@ -3158,6 +3200,9 @@ static void __devexit natsemi_remove1 (struct pci_dev *pdev)
* * netdev_timer: timer stopped by natsemi_suspend.
* * intr_handler: doesn't acquire the spinlock. suspend calls
* disable_irq() to enforce synchronization.
* * natsemi_poll: checks before reenabling interrupts. suspend
* sets hands_off, disables interrupts and then waits with
* netif_poll_disable().
*
* Interrupts must be disabled, otherwise hands_off can cause irq storms.
*/
Expand All @@ -3183,6 +3228,8 @@ static int natsemi_suspend (struct pci_dev *pdev, pm_message_t state)
spin_unlock_irq(&np->lock);
enable_irq(dev->irq);

netif_poll_disable(dev);

/* Update the error counts. */
__get_stats(dev);

Expand Down Expand Up @@ -3235,6 +3282,7 @@ static int natsemi_resume (struct pci_dev *pdev)
mod_timer(&np->timer, jiffies + 1*HZ);
}
netif_device_attach(dev);
netif_poll_enable(dev);
out:
rtnl_unlock();
return 0;
Expand Down

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