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>

1 files changed, 23 insertions, 0 deletions

diff --git a/drivers/net/forcedeth.c b/drivers/net/forcedeth.c
index f9a846b1b92f..d0b1d9f17a5d 100644
--- 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 */