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smsc95xx: add tx checksum offload support

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LAN9500 supports tx checksum offload, which slightly decreases cpu
utilisation.  The benefit isn't very large because we still require
the skb to be linearized, but it does save a few cycles.

This patch adds support for it, and enables it by default.

Signed-off-by: Steve Glendinning <steve.glendinning@smsc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Steve Glendinning 2008-11-20 04:19:21 -08:00 committed by David S. Miller
parent 8761169cf1
commit f7b29271c3
1 changed files with 65 additions and 10 deletions
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75
drivers/net/usb/smsc95xx.c
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@ -31,7 +31,7 @@
#include "smsc95xx.h"
#define SMSC_CHIPNAME "smsc95xx"
#define SMSC_DRIVER_VERSION "1.0.3"
#define SMSC_DRIVER_VERSION "1.0.4"
#define HS_USB_PKT_SIZE (512)
#define FS_USB_PKT_SIZE (64)
#define DEFAULT_HS_BURST_CAP_SIZE (16 * 1024 + 5 * HS_USB_PKT_SIZE)
@ -40,15 +40,18 @@
#define MAX_SINGLE_PACKET_SIZE (2048)
#define LAN95XX_EEPROM_MAGIC (0x9500)
#define EEPROM_MAC_OFFSET (0x01)
#define DEFAULT_TX_CSUM_ENABLE (true)
#define DEFAULT_RX_CSUM_ENABLE (true)
#define SMSC95XX_INTERNAL_PHY_ID (1)
#define SMSC95XX_TX_OVERHEAD (8)
#define SMSC95XX_TX_OVERHEAD_CSUM (12)
#define FLOW_CTRL_TX (1)
#define FLOW_CTRL_RX (2)
struct smsc95xx_priv {
u32 mac_cr;
spinlock_t mac_cr_lock;
bool use_tx_csum;
bool use_rx_csum;
};
@ -556,9 +559,10 @@ static void smsc95xx_status(struct usbnet *dev, struct urb *urb)
devwarn(dev, "unexpected interrupt, intdata=0x%08X", intdata);
}
/* Enable or disable Rx checksum offload engine */
static int smsc95xx_set_rx_csum(struct usbnet *dev, bool enable)
/* Enable or disable Tx & Rx checksum offload engines */
static int smsc95xx_set_csums(struct usbnet *dev)
{
struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
u32 read_buf;
int ret = smsc95xx_read_reg(dev, COE_CR, &read_buf);
if (ret < 0) {
@ -566,7 +570,12 @@ static int smsc95xx_set_rx_csum(struct usbnet *dev, bool enable)
return ret;
}
if (enable)
if (pdata->use_tx_csum)
read_buf |= Tx_COE_EN_;
else
read_buf &= ~Tx_COE_EN_;
if (pdata->use_rx_csum)
read_buf |= Rx_COE_EN_;
else
read_buf &= ~Rx_COE_EN_;
@ -626,7 +635,26 @@ static int smsc95xx_ethtool_set_rx_csum(struct net_device *netdev, u32 val)
pdata->use_rx_csum = !!val;
return smsc95xx_set_rx_csum(dev, pdata->use_rx_csum);
return smsc95xx_set_csums(dev);
}
static u32 smsc95xx_ethtool_get_tx_csum(struct net_device *netdev)
{
struct usbnet *dev = netdev_priv(netdev);
struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
return pdata->use_tx_csum;
}
static int smsc95xx_ethtool_set_tx_csum(struct net_device *netdev, u32 val)
{
struct usbnet *dev = netdev_priv(netdev);
struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
pdata->use_tx_csum = !!val;
ethtool_op_set_tx_hw_csum(netdev, pdata->use_tx_csum);
return smsc95xx_set_csums(dev);
}
static struct ethtool_ops smsc95xx_ethtool_ops = {
@ -640,6 +668,8 @@ static struct ethtool_ops smsc95xx_ethtool_ops = {
.get_eeprom_len = smsc95xx_ethtool_get_eeprom_len,
.get_eeprom = smsc95xx_ethtool_get_eeprom,
.set_eeprom = smsc95xx_ethtool_set_eeprom,
.get_tx_csum = smsc95xx_ethtool_get_tx_csum,
.set_tx_csum = smsc95xx_ethtool_set_tx_csum,
.get_rx_csum = smsc95xx_ethtool_get_rx_csum,
.set_rx_csum = smsc95xx_ethtool_set_rx_csum,
};
@ -757,6 +787,7 @@ static int smsc95xx_phy_initialize(struct usbnet *dev)
static int smsc95xx_reset(struct usbnet *dev)
{
struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
struct net_device *netdev = dev->net;
u32 read_buf, write_buf, burst_cap;
int ret = 0, timeout;
@ -968,10 +999,11 @@ static int smsc95xx_reset(struct usbnet *dev)
return ret;
}
/* Enable or disable Rx checksum offload engine */
ret = smsc95xx_set_rx_csum(dev, pdata->use_rx_csum);
/* Enable or disable checksum offload engines */
ethtool_op_set_tx_hw_csum(netdev, pdata->use_tx_csum);
ret = smsc95xx_set_csums(dev);
if (ret < 0) {
devwarn(dev, "Failed to set Rx csum offload: %d", ret);
devwarn(dev, "Failed to set csum offload: %d", ret);
return ret;
}
@ -1027,6 +1059,7 @@ static int smsc95xx_bind(struct usbnet *dev, struct usb_interface *intf)
spin_lock_init(&pdata->mac_cr_lock);
pdata->use_tx_csum = DEFAULT_TX_CSUM_ENABLE;
pdata->use_rx_csum = DEFAULT_RX_CSUM_ENABLE;
/* Init all registers */
@ -1146,22 +1179,44 @@ static int smsc95xx_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
return 1;
}
static u32 smsc95xx_calc_csum_preamble(struct sk_buff *skb)
{
int len = skb->data - skb->head;
u16 high_16 = (u16)(skb->csum_offset + skb->csum_start - len);
u16 low_16 = (u16)(skb->csum_start - len);
return (high_16 << 16) | low_16;
}
static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev,
struct sk_buff *skb, gfp_t flags)
{
struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
bool csum = pdata->use_tx_csum && (skb->ip_summed == CHECKSUM_PARTIAL);
int overhead = csum ? SMSC95XX_TX_OVERHEAD_CSUM : SMSC95XX_TX_OVERHEAD;
u32 tx_cmd_a, tx_cmd_b;
if (skb_headroom(skb) < SMSC95XX_TX_OVERHEAD) {
/* We do not advertise SG, so skbs should be already linearized */
BUG_ON(skb_shinfo(skb)->nr_frags);
if (skb_headroom(skb) < overhead) {
struct sk_buff *skb2 = skb_copy_expand(skb,
SMSC95XX_TX_OVERHEAD, 0, flags);
overhead, 0, flags);
dev_kfree_skb_any(skb);
skb = skb2;
if (!skb)
return NULL;
}
if (csum) {
u32 csum_preamble = smsc95xx_calc_csum_preamble(skb);
skb_push(skb, 4);
memcpy(skb->data, &csum_preamble, 4);
}
skb_push(skb, 4);
tx_cmd_b = (u32)(skb->len - 4);
if (csum)
tx_cmd_b |= TX_CMD_B_CSUM_ENABLE;
cpu_to_le32s(&tx_cmd_b);
memcpy(skb->data, &tx_cmd_b, 4);