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gianfar: Avoid unnecessary reg accesses in adjust_link()
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For phy devices that don't issue interrupts upon link
state changes, phylib polls the link state resulting in
repeated calls to adjust_link(), even if the link state
didn't change.  As a result, some mac registers are
repeatedly read and written with the same values, which
is not ok.

To fix this, adjust_link() has been refactored to check
first whether the link state has changed and to take action
only if needed, updating mac registers and local state
variables.  The 'new_state' local flag, set if one of the
link params changed (link, speed or duplex), has been
rendered useless and removed by this refactoring.

Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Claudiu Manoil authored and David S. Miller committed Apr 30, 2014
1 parent 0cda345 commit 6ce29b0
Showing 1 changed file with 113 additions and 110 deletions.
223 changes: 113 additions & 110 deletions drivers/net/ethernet/freescale/gianfar.c
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Original file line number Diff line number Diff line change
Expand Up @@ -121,6 +121,7 @@ static irqreturn_t gfar_error(int irq, void *dev_id);
static irqreturn_t gfar_transmit(int irq, void *dev_id);
static irqreturn_t gfar_interrupt(int irq, void *dev_id);
static void adjust_link(struct net_device *dev);
static noinline void gfar_update_link_state(struct gfar_private *priv);
static int init_phy(struct net_device *dev);
static int gfar_probe(struct platform_device *ofdev);
static int gfar_remove(struct platform_device *ofdev);
Expand Down Expand Up @@ -3076,41 +3077,6 @@ static irqreturn_t gfar_interrupt(int irq, void *grp_id)
return IRQ_HANDLED;
}

static u32 gfar_get_flowctrl_cfg(struct gfar_private *priv)
{
struct phy_device *phydev = priv->phydev;
u32 val = 0;

if (!phydev->duplex)
return val;

if (!priv->pause_aneg_en) {
if (priv->tx_pause_en)
val |= MACCFG1_TX_FLOW;
if (priv->rx_pause_en)
val |= MACCFG1_RX_FLOW;
} else {
u16 lcl_adv, rmt_adv;
u8 flowctrl;
/* get link partner capabilities */
rmt_adv = 0;
if (phydev->pause)
rmt_adv = LPA_PAUSE_CAP;
if (phydev->asym_pause)
rmt_adv |= LPA_PAUSE_ASYM;

lcl_adv = mii_advertise_flowctrl(phydev->advertising);

flowctrl = mii_resolve_flowctrl_fdx(lcl_adv, rmt_adv);
if (flowctrl & FLOW_CTRL_TX)
val |= MACCFG1_TX_FLOW;
if (flowctrl & FLOW_CTRL_RX)
val |= MACCFG1_RX_FLOW;
}

return val;
}

/* Called every time the controller might need to be made
* aware of new link state. The PHY code conveys this
* information through variables in the phydev structure, and this
Expand All @@ -3120,83 +3086,12 @@ static u32 gfar_get_flowctrl_cfg(struct gfar_private *priv)
static void adjust_link(struct net_device *dev)
{
struct gfar_private *priv = netdev_priv(dev);
struct gfar __iomem *regs = priv->gfargrp[0].regs;
struct phy_device *phydev = priv->phydev;
int new_state = 0;

if (test_bit(GFAR_RESETTING, &priv->state))
return;

if (phydev->link) {
u32 tempval1 = gfar_read(&regs->maccfg1);
u32 tempval = gfar_read(&regs->maccfg2);
u32 ecntrl = gfar_read(&regs->ecntrl);

/* Now we make sure that we can be in full duplex mode.
* If not, we operate in half-duplex mode.
*/
if (phydev->duplex != priv->oldduplex) {
new_state = 1;
if (!(phydev->duplex))
tempval &= ~(MACCFG2_FULL_DUPLEX);
else
tempval |= MACCFG2_FULL_DUPLEX;

priv->oldduplex = phydev->duplex;
}

if (phydev->speed != priv->oldspeed) {
new_state = 1;
switch (phydev->speed) {
case 1000:
tempval =
((tempval & ~(MACCFG2_IF)) | MACCFG2_GMII);

ecntrl &= ~(ECNTRL_R100);
break;
case 100:
case 10:
tempval =
((tempval & ~(MACCFG2_IF)) | MACCFG2_MII);

/* Reduced mode distinguishes
* between 10 and 100
*/
if (phydev->speed == SPEED_100)
ecntrl |= ECNTRL_R100;
else
ecntrl &= ~(ECNTRL_R100);
break;
default:
netif_warn(priv, link, dev,
"Ack! Speed (%d) is not 10/100/1000!\n",
phydev->speed);
break;
}

priv->oldspeed = phydev->speed;
}

tempval1 &= ~(MACCFG1_TX_FLOW | MACCFG1_RX_FLOW);
tempval1 |= gfar_get_flowctrl_cfg(priv);

gfar_write(&regs->maccfg1, tempval1);
gfar_write(&regs->maccfg2, tempval);
gfar_write(&regs->ecntrl, ecntrl);

if (!priv->oldlink) {
new_state = 1;
priv->oldlink = 1;
}
} else if (priv->oldlink) {
new_state = 1;
priv->oldlink = 0;
priv->oldspeed = 0;
priv->oldduplex = -1;
}

if (new_state && netif_msg_link(priv))
phy_print_status(phydev);
if (unlikely(phydev->link != priv->oldlink ||
phydev->duplex != priv->oldduplex ||
phydev->speed != priv->oldspeed))
gfar_update_link_state(priv);
}

/* Update the hash table based on the current list of multicast
Expand Down Expand Up @@ -3442,6 +3337,114 @@ static irqreturn_t gfar_error(int irq, void *grp_id)
return IRQ_HANDLED;
}

static u32 gfar_get_flowctrl_cfg(struct gfar_private *priv)
{
struct phy_device *phydev = priv->phydev;
u32 val = 0;

if (!phydev->duplex)
return val;

if (!priv->pause_aneg_en) {
if (priv->tx_pause_en)
val |= MACCFG1_TX_FLOW;
if (priv->rx_pause_en)
val |= MACCFG1_RX_FLOW;
} else {
u16 lcl_adv, rmt_adv;
u8 flowctrl;
/* get link partner capabilities */
rmt_adv = 0;
if (phydev->pause)
rmt_adv = LPA_PAUSE_CAP;
if (phydev->asym_pause)
rmt_adv |= LPA_PAUSE_ASYM;

lcl_adv = mii_advertise_flowctrl(phydev->advertising);

flowctrl = mii_resolve_flowctrl_fdx(lcl_adv, rmt_adv);
if (flowctrl & FLOW_CTRL_TX)
val |= MACCFG1_TX_FLOW;
if (flowctrl & FLOW_CTRL_RX)
val |= MACCFG1_RX_FLOW;
}

return val;
}

static noinline void gfar_update_link_state(struct gfar_private *priv)
{
struct gfar __iomem *regs = priv->gfargrp[0].regs;
struct phy_device *phydev = priv->phydev;

if (unlikely(test_bit(GFAR_RESETTING, &priv->state)))
return;

if (phydev->link) {
u32 tempval1 = gfar_read(&regs->maccfg1);
u32 tempval = gfar_read(&regs->maccfg2);
u32 ecntrl = gfar_read(&regs->ecntrl);

if (phydev->duplex != priv->oldduplex) {
if (!(phydev->duplex))
tempval &= ~(MACCFG2_FULL_DUPLEX);
else
tempval |= MACCFG2_FULL_DUPLEX;

priv->oldduplex = phydev->duplex;
}

if (phydev->speed != priv->oldspeed) {
switch (phydev->speed) {
case 1000:
tempval =
((tempval & ~(MACCFG2_IF)) | MACCFG2_GMII);

ecntrl &= ~(ECNTRL_R100);
break;
case 100:
case 10:
tempval =
((tempval & ~(MACCFG2_IF)) | MACCFG2_MII);

/* Reduced mode distinguishes
* between 10 and 100
*/
if (phydev->speed == SPEED_100)
ecntrl |= ECNTRL_R100;
else
ecntrl &= ~(ECNTRL_R100);
break;
default:
netif_warn(priv, link, priv->ndev,
"Ack! Speed (%d) is not 10/100/1000!\n",
phydev->speed);
break;
}

priv->oldspeed = phydev->speed;
}

tempval1 &= ~(MACCFG1_TX_FLOW | MACCFG1_RX_FLOW);
tempval1 |= gfar_get_flowctrl_cfg(priv);

gfar_write(&regs->maccfg1, tempval1);
gfar_write(&regs->maccfg2, tempval);
gfar_write(&regs->ecntrl, ecntrl);

if (!priv->oldlink)
priv->oldlink = 1;

} else if (priv->oldlink) {
priv->oldlink = 0;
priv->oldspeed = 0;
priv->oldduplex = -1;
}

if (netif_msg_link(priv))
phy_print_status(phydev);
}

static struct of_device_id gfar_match[] =
{
{
Expand Down

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