forcedeth: add clock gating feature <resend>

This patch adds new logic to support a clock gating feature found on the
latest set of chipsets. The clock gating is performed on the tx/rx
engines when the link is disconnected. Clock gating helps in reducing
power consumption.

* modified based on comments from netdev

Signed-off-by: Ayaz Abdulla <aabdulla@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/forcedeth.c b/drivers/net/forcedeth.c
index f9a846b..d0b1d9f 100644 (file)
--- a/drivers/net/forcedeth.c
+++ b/drivers/net/forcedeth.c
@@ -343,6 +343,7 @@ enum {
 #define NVREG_POWERSTATE2_POWERUP_MASK         0x0F15
 #define NVREG_POWERSTATE2_POWERUP_REV_A3       0x0001
 #define NVREG_POWERSTATE2_PHY_RESET            0x0004
+#define NVREG_POWERSTATE2_GATE_CLOCKS          0x0F00
 };
 
 /* Big endian: should work, but is untested */
@@ -1017,6 +1018,23 @@ static int using_multi_irqs(struct net_device *dev)
                return 1;
 }
 
+static void nv_txrx_gate(struct net_device *dev, bool gate)
+{
+       struct fe_priv *np = get_nvpriv(dev);
+       u8 __iomem *base = get_hwbase(dev);
+       u32 powerstate;
+
+       if (!np->mac_in_use &&
+           (np->driver_data & DEV_HAS_POWER_CNTRL)) {
+               powerstate = readl(base + NvRegPowerState2);
+               if (gate)
+                       powerstate |= NVREG_POWERSTATE2_GATE_CLOCKS;
+               else
+                       powerstate &= ~NVREG_POWERSTATE2_GATE_CLOCKS;
+               writel(powerstate, base + NvRegPowerState2);
+       }
+}
+
 static void nv_enable_irq(struct net_device *dev)
 {
        struct fe_priv *np = get_nvpriv(dev);
@@ -3394,12 +3412,14 @@ static void nv_linkchange(struct net_device *dev)
                if (!netif_carrier_ok(dev)) {
                        netif_carrier_on(dev);
                        printk(KERN_INFO "%s: link up.\n", dev->name);
+                       nv_txrx_gate(dev, false);
                        nv_start_rx(dev);
                }
        } else {
                if (netif_carrier_ok(dev)) {
                        netif_carrier_off(dev);
                        printk(KERN_INFO "%s: link down.\n", dev->name);
+                       nv_txrx_gate(dev, true);
                        nv_stop_rx(dev);
                }
        }
@@ -5327,6 +5347,7 @@ static int nv_open(struct net_device *dev)
        mii_rw(dev, np->phyaddr, MII_BMCR,
               mii_rw(dev, np->phyaddr, MII_BMCR, MII_READ) & ~BMCR_PDOWN);
 
+       nv_txrx_gate(dev, false);
        /* erase previous misconfiguration */
        if (np->driver_data & DEV_HAS_POWER_CNTRL)
                nv_mac_reset(dev);
@@ -5514,12 +5535,14 @@ static int nv_close(struct net_device *dev)
        nv_drain_rxtx(dev);
 
        if (np->wolenabled) {
+               nv_txrx_gate(dev, false);
                writel(NVREG_PFF_ALWAYS|NVREG_PFF_MYADDR, base + NvRegPacketFilterFlags);
                nv_start_rx(dev);
        } else {
                /* power down phy */
                mii_rw(dev, np->phyaddr, MII_BMCR,
                       mii_rw(dev, np->phyaddr, MII_BMCR, MII_READ)|BMCR_PDOWN);
+               nv_txrx_gate(dev, true);
        }
 
        /* FIXME: power down nic */