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Date: Sat, 12 Mar 2011 04:20:12 -0800
From: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To: davem@...emloft.net
Cc: Carolyn Wyborny <carolyn.wyborny@...el.com>,
netdev@...r.kernel.org, gospo@...hat.com, bphilips@...ell.com,
Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net-next-2.6 05/21] igb: Add DMA Coalescing feature to driver
From: Carolyn Wyborny <carolyn.wyborny@...el.com>
This patch add DMA Coalescing which is a power-saving feature that
coalesces DMA writes in order to stay in a low-power state as much
as possible. Feature is disabled by default.
Signed-off-by: Carolyn Wyborny <carolyn.wyborny@...el.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
drivers/net/igb/e1000_defines.h | 29 ++++++++++++++++++-
drivers/net/igb/e1000_regs.h | 9 ++++++
drivers/net/igb/igb.h | 6 ++++
drivers/net/igb/igb_ethtool.c | 6 ++++
drivers/net/igb/igb_main.c | 59 ++++++++++++++++++++++++++++++++++++++-
5 files changed, 107 insertions(+), 2 deletions(-)
diff --git a/drivers/net/igb/e1000_defines.h b/drivers/net/igb/e1000_defines.h
index 97969ad..9bb1928 100644
--- a/drivers/net/igb/e1000_defines.h
+++ b/drivers/net/igb/e1000_defines.h
@@ -287,7 +287,34 @@
#define E1000_TCTL_COLD 0x003ff000 /* collision distance */
#define E1000_TCTL_RTLC 0x01000000 /* Re-transmit on late collision */
-/* Transmit Arbitration Count */
+/* DMA Coalescing register fields */
+#define E1000_DMACR_DMACWT_MASK 0x00003FFF /* DMA Coalescing
+ * Watchdog Timer */
+#define E1000_DMACR_DMACTHR_MASK 0x00FF0000 /* DMA Coalescing Receive
+ * Threshold */
+#define E1000_DMACR_DMACTHR_SHIFT 16
+#define E1000_DMACR_DMAC_LX_MASK 0x30000000 /* Lx when no PCIe
+ * transactions */
+#define E1000_DMACR_DMAC_LX_SHIFT 28
+#define E1000_DMACR_DMAC_EN 0x80000000 /* Enable DMA Coalescing */
+
+#define E1000_DMCTXTH_DMCTTHR_MASK 0x00000FFF /* DMA Coalescing Transmit
+ * Threshold */
+
+#define E1000_DMCTLX_TTLX_MASK 0x00000FFF /* Time to LX request */
+
+#define E1000_DMCRTRH_UTRESH_MASK 0x0007FFFF /* Receive Traffic Rate
+ * Threshold */
+#define E1000_DMCRTRH_LRPRCW 0x80000000 /* Rcv packet rate in
+ * current window */
+
+#define E1000_DMCCNT_CCOUNT_MASK 0x01FFFFFF /* DMA Coal Rcv Traffic
+ * Current Cnt */
+
+#define E1000_FCRTC_RTH_COAL_MASK 0x0003FFF0 /* Flow ctrl Rcv Threshold
+ * High val */
+#define E1000_FCRTC_RTH_COAL_SHIFT 4
+#define E1000_PCIEMISC_LX_DECISION 0x00000080 /* Lx power decision */
/* SerDes Control */
#define E1000_SCTL_DISABLE_SERDES_LOOPBACK 0x0400
diff --git a/drivers/net/igb/e1000_regs.h b/drivers/net/igb/e1000_regs.h
index b2f8e59..ad77ed5 100644
--- a/drivers/net/igb/e1000_regs.h
+++ b/drivers/net/igb/e1000_regs.h
@@ -106,6 +106,15 @@
#define E1000_RQDPC(_n) (0x0C030 + ((_n) * 0x40))
+/* DMA Coalescing registers */
+#define E1000_DMACR 0x02508 /* Control Register */
+#define E1000_DMCTXTH 0x03550 /* Transmit Threshold */
+#define E1000_DMCTLX 0x02514 /* Time to Lx Request */
+#define E1000_DMCRTRH 0x05DD0 /* Receive Packet Rate Threshold */
+#define E1000_DMCCNT 0x05DD4 /* Current Rx Count */
+#define E1000_FCRTC 0x02170 /* Flow Control Rx high watermark */
+#define E1000_PCIEMISC 0x05BB8 /* PCIE misc config register */
+
/* TX Rate Limit Registers */
#define E1000_RTTDQSEL 0x3604 /* Tx Desc Plane Queue Select - WO */
#define E1000_RTTBCNRC 0x36B0 /* Tx BCN Rate-Scheduler Config - WO */
diff --git a/drivers/net/igb/igb.h b/drivers/net/igb/igb.h
index bbc5ebf..1c687e2 100644
--- a/drivers/net/igb/igb.h
+++ b/drivers/net/igb/igb.h
@@ -333,6 +333,12 @@ struct igb_adapter {
#define IGB_FLAG_DCA_ENABLED (1 << 1)
#define IGB_FLAG_QUAD_PORT_A (1 << 2)
#define IGB_FLAG_QUEUE_PAIRS (1 << 3)
+#define IGB_FLAG_DMAC (1 << 4)
+
+/* DMA Coalescing defines */
+#define IGB_MIN_TXPBSIZE 20408
+#define IGB_TX_BUF_4096 4096
+#define IGB_DMCTLX_DCFLUSH_DIS 0x80000000 /* Disable DMA Coal Flush */
#define IGB_82576_TSYNC_SHIFT 19
#define IGB_82580_TSYNC_SHIFT 24
diff --git a/drivers/net/igb/igb_ethtool.c b/drivers/net/igb/igb_ethtool.c
index df15a91..d976733 100644
--- a/drivers/net/igb/igb_ethtool.c
+++ b/drivers/net/igb/igb_ethtool.c
@@ -2009,6 +2009,12 @@ static int igb_set_coalesce(struct net_device *netdev,
if ((adapter->flags & IGB_FLAG_QUEUE_PAIRS) && ec->tx_coalesce_usecs)
return -EINVAL;
+ /* If ITR is disabled, disable DMAC */
+ if (ec->rx_coalesce_usecs == 0) {
+ if (adapter->flags & IGB_FLAG_DMAC)
+ adapter->flags &= ~IGB_FLAG_DMAC;
+ }
+
/* convert to rate of irq's per second */
if (ec->rx_coalesce_usecs && ec->rx_coalesce_usecs <= 3)
adapter->rx_itr_setting = ec->rx_coalesce_usecs;
diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index 8c6af11..49476f7 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -1674,7 +1674,58 @@ void igb_reset(struct igb_adapter *adapter)
if (hw->mac.ops.init_hw(hw))
dev_err(&pdev->dev, "Hardware Error\n");
+ if (hw->mac.type > e1000_82580) {
+ if (adapter->flags & IGB_FLAG_DMAC) {
+ u32 reg;
+ /*
+ * DMA Coalescing high water mark needs to be higher
+ * than * the * Rx threshold. The Rx threshold is
+ * currently * pba - 6, so we * should use a high water
+ * mark of pba * - 4. */
+ hwm = (pba - 4) << 10;
+
+ reg = (((pba-6) << E1000_DMACR_DMACTHR_SHIFT)
+ & E1000_DMACR_DMACTHR_MASK);
+
+ /* transition to L0x or L1 if available..*/
+ reg |= (E1000_DMACR_DMAC_EN | E1000_DMACR_DMAC_LX_MASK);
+
+ /* watchdog timer= +-1000 usec in 32usec intervals */
+ reg |= (1000 >> 5);
+ wr32(E1000_DMACR, reg);
+
+ /* no lower threshold to disable coalescing(smart fifb)
+ * -UTRESH=0*/
+ wr32(E1000_DMCRTRH, 0);
+
+ /* set hwm to PBA - 2 * max frame size */
+ wr32(E1000_FCRTC, hwm);
+
+ /*
+ * This sets the time to wait before requesting tran-
+ * sition to * low power state to number of usecs needed
+ * to receive 1 512 * byte frame at gigabit line rate
+ */
+ reg = rd32(E1000_DMCTLX);
+ reg |= IGB_DMCTLX_DCFLUSH_DIS;
+
+ /* Delay 255 usec before entering Lx state. */
+ reg |= 0xFF;
+ wr32(E1000_DMCTLX, reg);
+
+ /* free space in Tx packet buffer to wake from DMAC */
+ wr32(E1000_DMCTXTH,
+ (IGB_MIN_TXPBSIZE -
+ (IGB_TX_BUF_4096 + adapter->max_frame_size))
+ >> 6);
+
+ /* make low power state decision controlled by DMAC */
+ reg = rd32(E1000_PCIEMISC);
+ reg |= E1000_PCIEMISC_LX_DECISION;
+ wr32(E1000_PCIEMISC, reg);
+ } /* end if IGB_FLAG_DMAC set */
+ }
if (hw->mac.type == e1000_82580) {
u32 reg = rd32(E1000_PCIEMISC);
wr32(E1000_PCIEMISC,
@@ -2157,6 +2208,9 @@ static void __devinit igb_probe_vfs(struct igb_adapter * adapter)
random_ether_addr(mac_addr);
igb_set_vf_mac(adapter, i, mac_addr);
}
+ /* DMA Coalescing is not supported in IOV mode. */
+ if (adapter->flags & IGB_FLAG_DMAC)
+ adapter->flags &= ~IGB_FLAG_DMAC;
}
#endif /* CONFIG_PCI_IOV */
}
@@ -2331,6 +2385,9 @@ static int __devinit igb_sw_init(struct igb_adapter *adapter)
/* Explicitly disable IRQ since the NIC can be in any state. */
igb_irq_disable(adapter);
+ if (hw->mac.type == e1000_i350)
+ adapter->flags &= ~IGB_FLAG_DMAC;
+
set_bit(__IGB_DOWN, &adapter->state);
return 0;
}
--
1.7.4
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