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net/enc28j60: low power mode 

Keep enc28j60 chips in low-power mode when they're not in use.
At typically 120 mA, these chips run hot even when idle; this
low power mode cuts that power usage by a factor of around 100.

This version provides a generic routine to poll a register until
its masked value equals some value ... e.g. bit set or cleared.
It's basically what the previous wait_phy_ready() did, but this
version is generalized to support the handshaking needed to
enter and exit low power mode.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Claudio Lanconelli <lanconelli.claudio@eptar.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
David Brownell 2008-06-12 21:38:06 -07:00 committed by Jeff Garzik
parent 6fd65882f5
commit 7dac6f8df6
1 changed files with 61 additions and 27 deletions
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88
drivers/net/enc28j60.c
View File

@ -400,26 +400,31 @@ enc28j60_packet_write(struct enc28j60_net *priv, int len, const u8 *data)
mutex_unlock(&priv->lock);
}
static unsigned long msec20_to_jiffies;
static int poll_ready(struct enc28j60_net *priv, u8 reg, u8 mask, u8 val)
{
unsigned long timeout = jiffies + msec20_to_jiffies;
/* 20 msec timeout read */
while ((nolock_regb_read(priv, reg) & mask) != val) {
if (time_after(jiffies, timeout)) {
if (netif_msg_drv(priv))
dev_dbg(&priv->spi->dev,
"reg %02x ready timeout!\n", reg);
return -ETIMEDOUT;
}
cpu_relax();
}
return 0;
}
/*
* Wait until the PHY operation is complete.
*/
static int wait_phy_ready(struct enc28j60_net *priv)
{
unsigned long timeout = jiffies + 20 * HZ / 1000;
int ret = 1;
/* 20 msec timeout read */
while (nolock_regb_read(priv, MISTAT) & MISTAT_BUSY) {
if (time_after(jiffies, timeout)) {
if (netif_msg_drv(priv))
printk(KERN_DEBUG DRV_NAME
": PHY ready timeout!\n");
ret = 0;
break;
}
cpu_relax();
}
return ret;
return poll_ready(priv, MISTAT, MISTAT_BUSY, 0) ? 0 : 1;
}
/*
@ -594,6 +599,32 @@ static void nolock_txfifo_init(struct enc28j60_net *priv, u16 start, u16 end)
nolock_regw_write(priv, ETXNDL, end);
}
/*
* Low power mode shrinks power consumption about 100x, so we'd like
* the chip to be in that mode whenever it's inactive. (However, we
* can't stay in lowpower mode during suspend with WOL active.)
*/
static void enc28j60_lowpower(struct enc28j60_net *priv, bool is_low)
{
if (netif_msg_drv(priv))
dev_dbg(&priv->spi->dev, "%s power...\n",
is_low ? "low" : "high");
mutex_lock(&priv->lock);
if (is_low) {
nolock_reg_bfclr(priv, ECON1, ECON1_RXEN);
poll_ready(priv, ESTAT, ESTAT_RXBUSY, 0);
poll_ready(priv, ECON1, ECON1_TXRTS, 0);
/* ECON2_VRPS was set during initialization */
nolock_reg_bfset(priv, ECON2, ECON2_PWRSV);
} else {
nolock_reg_bfclr(priv, ECON2, ECON2_PWRSV);
poll_ready(priv, ESTAT, ESTAT_CLKRDY, ESTAT_CLKRDY);
/* caller sets ECON1_RXEN */
}
mutex_unlock(&priv->lock);
}
static int enc28j60_hw_init(struct enc28j60_net *priv)
{
u8 reg;
@ -612,8 +643,8 @@ static int enc28j60_hw_init(struct enc28j60_net *priv)
priv->tx_retry_count = 0;
priv->max_pk_counter = 0;
priv->rxfilter = RXFILTER_NORMAL;
/* enable address auto increment */
nolock_regb_write(priv, ECON2, ECON2_AUTOINC);
/* enable address auto increment and voltage regulator powersave */
nolock_regb_write(priv, ECON2, ECON2_AUTOINC | ECON2_VRPS);
nolock_rxfifo_init(priv, RXSTART_INIT, RXEND_INIT);
nolock_txfifo_init(priv, TXSTART_INIT, TXEND_INIT);
@ -690,7 +721,7 @@ static int enc28j60_hw_init(struct enc28j60_net *priv)
static void enc28j60_hw_enable(struct enc28j60_net *priv)
{
/* enable interrutps */
/* enable interrupts */
if (netif_msg_hw(priv))
printk(KERN_DEBUG DRV_NAME ": %s() enabling interrupts.\n",
__FUNCTION__);
@ -726,15 +757,12 @@ enc28j60_setlink(struct net_device *ndev, u8 autoneg, u16 speed, u8 duplex)
int ret = 0;
if (!priv->hw_enable) {
if (autoneg == AUTONEG_DISABLE && speed == SPEED_10) {
/* link is in low power mode now; duplex setting
* will take effect on next enc28j60_hw_init().
*/
if (autoneg == AUTONEG_DISABLE && speed == SPEED_10)
priv->full_duplex = (duplex == DUPLEX_FULL);
if (!enc28j60_hw_init(priv)) {
if (netif_msg_drv(priv))
dev_err(&ndev->dev,
"hw_reset() failed\n");
ret = -EINVAL;
}
} else {
else {
if (netif_msg_link(priv))
dev_warn(&ndev->dev,
"unsupported link setting\n");
@ -1307,7 +1335,8 @@ static int enc28j60_net_open(struct net_device *dev)
}
return -EADDRNOTAVAIL;
}
/* Reset the hardware here */
/* Reset the hardware here (and take it out of low power mode) */
enc28j60_lowpower(priv, false);
enc28j60_hw_disable(priv);
if (!enc28j60_hw_init(priv)) {
if (netif_msg_ifup(priv))
@ -1337,6 +1366,7 @@ static int enc28j60_net_close(struct net_device *dev)
printk(KERN_DEBUG DRV_NAME ": %s() enter\n", __FUNCTION__);
enc28j60_hw_disable(priv);
enc28j60_lowpower(priv, true);
netif_stop_queue(dev);
return 0;
@ -1537,6 +1567,8 @@ static int __devinit enc28j60_probe(struct spi_device *spi)
dev->watchdog_timeo = TX_TIMEOUT;
SET_ETHTOOL_OPS(dev, &enc28j60_ethtool_ops);
enc28j60_lowpower(priv, true);
ret = register_netdev(dev);
if (ret) {
if (netif_msg_probe(priv))
@ -1581,6 +1613,8 @@ static struct spi_driver enc28j60_driver = {
static int __init enc28j60_init(void)
{
msec20_to_jiffies = msecs_to_jiffies(20);
return spi_register_driver(&enc28j60_driver);
}