alistair23-linux/drivers/net/bfin_mac.h
Sonic Zhang 4fcc3d3409 netdev:bfin_mac: reclaim and free tx skb as soon as possible after transfer
SKBs hold onto resources that can't be held indefinitely, such as TCP
socket references and netfilter conntrack state.  So if a packet is left
in TX ring for a long time, there might be a TCP socket that cannot be
closed and freed up.

Current blackfin EMAC driver always reclaim and free used tx skbs in future
transfers. The problem is that future transfer may not come as soon as
possible. This patch start a timer after transfer to reclaim and free skb.
There is nearly no performance drop with this patch.

TX interrupt is not enabled because of a strange behavior of the Blackfin EMAC.
If EMAC TX transfer control is turned on, endless TX interrupts are triggered
no matter if TX DMA is enabled or not. Since DMA walks down the ring automatically,
TX transfer control can't be turned off in the middle. The only way is to disable
TX interrupt completely.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-15 15:04:10 -07:00

96 lines
2.1 KiB
C

/*
* Blackfin On-Chip MAC Driver
*
* Copyright 2004-2007 Analog Devices Inc.
*
* Enter bugs at http://blackfin.uclinux.org/
*
* Licensed under the GPL-2 or later.
*/
#ifndef _BFIN_MAC_H_
#define _BFIN_MAC_H_
#include <linux/net_tstamp.h>
#include <linux/clocksource.h>
#include <linux/timecompare.h>
#include <linux/timer.h>
#define BFIN_MAC_CSUM_OFFLOAD
#define TX_RECLAIM_JIFFIES (HZ / 5)
struct dma_descriptor {
struct dma_descriptor *next_dma_desc;
unsigned long start_addr;
unsigned short config;
unsigned short x_count;
};
struct status_area_rx {
#if defined(BFIN_MAC_CSUM_OFFLOAD)
unsigned short ip_hdr_csum; /* ip header checksum */
/* ip payload(udp or tcp or others) checksum */
unsigned short ip_payload_csum;
#endif
unsigned long status_word; /* the frame status word */
};
struct status_area_tx {
unsigned long status_word; /* the frame status word */
};
/* use two descriptors for a packet */
struct net_dma_desc_rx {
struct net_dma_desc_rx *next;
struct sk_buff *skb;
struct dma_descriptor desc_a;
struct dma_descriptor desc_b;
struct status_area_rx status;
};
/* use two descriptors for a packet */
struct net_dma_desc_tx {
struct net_dma_desc_tx *next;
struct sk_buff *skb;
struct dma_descriptor desc_a;
struct dma_descriptor desc_b;
unsigned char packet[1560];
struct status_area_tx status;
};
struct bfin_mac_local {
/*
* these are things that the kernel wants me to keep, so users
* can find out semi-useless statistics of how well the card is
* performing
*/
struct net_device_stats stats;
unsigned char Mac[6]; /* MAC address of the board */
spinlock_t lock;
int wol; /* Wake On Lan */
int irq_wake_requested;
struct timer_list tx_reclaim_timer;
struct net_device *ndev;
/* MII and PHY stuffs */
int old_link; /* used by bf537_adjust_link */
int old_speed;
int old_duplex;
struct phy_device *phydev;
struct mii_bus *mii_bus;
#if defined(CONFIG_BFIN_MAC_USE_HWSTAMP)
struct cyclecounter cycles;
struct timecounter clock;
struct timecompare compare;
struct hwtstamp_config stamp_cfg;
#endif
};
extern void bfin_get_ether_addr(char *addr);
#endif