fec.c

实现一个网卡到内存空间的零拷贝程序

/*
 * Fast Ethernet Controller (FEC) driver for Motorola MPC8xx.
 * Copyright (c) 1997 Dan Malek ([e-mail])
 *
 * This version of the driver is specific to the FADS implementation,
 * since the board contains control registers external to the processor
 * for the control of the LevelOne LXT970 transceiver.  The MPC860T manual
 * describes connections using the internal parallel port I/O, which
 * is basically all of Port D.
 *
 * Includes support for the following PHYs: QS6612, LXT970, LXT971/2.
 *
 * Right now, I am very wasteful with the buffers.  I allocate memory
 * pages and then divide them into 2K frame buffers.  This way I know I
 * have buffers large enough to hold one frame within one buffer descriptor.
 * Once I get this working, I will use 64 or 128 byte CPM buffers, which
 * will be much more memory efficient and will easily handle lots of
 * small packets.
 *
 * Much better multiple PHY support by Magnus Damm.
 * Copyright (c) 2000 Ericsson Radio Systems AB.
 *
 * Make use of MII for PHY control configurable.
 * Some fixes.
 * Copyright (c) 2000 Wolfgang Denk, DENX Software Engineering.
 *
 * Experimental support for scatter/gather.
 * Joris van Rantwijk, May 2001.
 */

/* List of PHYs we wish to support.
*/
#define	CONFIG_FEC_LXT970
#undef	CONFIG_FEC_LXT971
#undef	CONFIG_FEC_QS6612

#if defined(CONFIG_FEC_SUPPORT_SG) && !defined(CONFIG_ENET_BIG_BUFFERS)
#error "Must use big buffers for scatter/gather support on MPC8xx FEC"
#endif

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#ifdef CONFIG_FEC_PACKETHOOK
#include <linux/pkthook.h>
#endif

#include <asm/8xx_immap.h>
#include <asm/pgtable.h>
#include <asm/mpc8xx.h>
#include <asm/irq.h>
#include <asm/bitops.h>
#include <asm/uaccess.h>
#include "commproc.h"

#ifdef	CONFIG_USE_MDIO
/* Forward declarations of some structures to support different PHYs
*/

typedef struct {
	uint mii_data;
	void (*funct)(uint mii_reg, struct net_device *dev);
} phy_cmd_t;

typedef struct {
	uint id;
	char *name;

	const phy_cmd_t *config;
	const phy_cmd_t *startup;
	const phy_cmd_t *ack_int;
	const phy_cmd_t *shutdown;
} phy_info_t;
#endif	/* CONFIG_USE_MDIO */

/* The number of Tx and Rx buffers.  These are allocated from the page
 * pool.  The code may assume these are power of two, so it is best
 * to keep them that size.
 * We don't need to allocate pages for the transmitter.  We just use
 * the skbuffer directly.
 */
#ifdef CONFIG_ENET_BIG_BUFFERS
#define FEC_ENET_RX_PAGES	16
#define FEC_ENET_RX_FRSIZE	2048
#define FEC_ENET_RX_FRPPG	(PAGE_SIZE / FEC_ENET_RX_FRSIZE)
#define RX_RING_SIZE		(FEC_ENET_RX_FRPPG * FEC_ENET_RX_PAGES)
#define TX_RING_SIZE		16	/* Must be power of two */
#define TX_RING_MOD_MASK	15	/*   for this to work */
#else
#define FEC_ENET_RX_PAGES	4
#define FEC_ENET_RX_FRSIZE	2048
#define FEC_ENET_RX_FRPPG	(PAGE_SIZE / FEC_ENET_RX_FRSIZE)
#define RX_RING_SIZE		(FEC_ENET_RX_FRPPG * FEC_ENET_RX_PAGES)
#define TX_RING_SIZE		8	/* Must be power of two */
#define TX_RING_MOD_MASK	7	/*   for this to work */
#endif

/* Interrupt events/masks.
*/
#define FEC_ENET_HBERR	((uint)0x80000000)	/* Heartbeat error */
#define FEC_ENET_BABR	((uint)0x40000000)	/* Babbling receiver */
#define FEC_ENET_BABT	((uint)0x20000000)	/* Babbling transmitter */
#define FEC_ENET_GRA	((uint)0x10000000)	/* Graceful stop complete */
#define FEC_ENET_TXF	((uint)0x08000000)	/* Full frame transmitted */
#define FEC_ENET_TXB	((uint)0x04000000)	/* A buffer was transmitted */
#define FEC_ENET_RXF	((uint)0x02000000)	/* Full frame received */
#define FEC_ENET_RXB	((uint)0x01000000)	/* A buffer was received */
#define FEC_ENET_MII	((uint)0x00800000)	/* MII interrupt */
#define FEC_ENET_EBERR	((uint)0x00400000)	/* SDMA bus error */

/*
*/
#define FEC_ECNTRL_PINMUX	0x00000004
#define FEC_ECNTRL_ETHER_EN	0x00000002
#define FEC_ECNTRL_RESET	0x00000001

#define FEC_RCNTRL_BC_REJ	0x00000010
#define FEC_RCNTRL_PROM		0x00000008
#define FEC_RCNTRL_MII_MODE	0x00000004
#define FEC_RCNTRL_DRT		0x00000002
#define FEC_RCNTRL_LOOP		0x00000001

#define FEC_TCNTRL_FDEN		0x00000004
#define FEC_TCNTRL_HBC		0x00000002
#define FEC_TCNTRL_GTS		0x00000001

/* Delay to wait for FEC reset command to complete (in us)
*/
#define FEC_RESET_DELAY		50

/* The FEC stores dest/src/type, data, and checksum for receive packets.
 */
#define PKT_MAXBUF_SIZE		1518
#define PKT_MINBUF_SIZE		64
#define PKT_MAXBLR_SIZE		1520

/* The FEC buffer descriptors track the ring buffers.  The rx_bd_base and
 * tx_bd_base always point to the base of the buffer descriptors.  The
 * cur_rx and cur_tx point to the currently available buffer.
 * The dirty_tx tracks the current buffer that is being sent by the
 * controller.  The cur_tx and dirty_tx are equal under both completely
 * empty and completely full conditions.  The empty/ready indicator in
 * the buffer descriptor determines the actual condition.
 */
struct fec_enet_private {
	/* The saved address of a sent-in-place packet/buffer, for skfree(). */
	struct	sk_buff* tx_skbuff[TX_RING_SIZE];
	ushort	skb_cur;
	ushort	skb_dirty;

	/* CPM dual port RAM relative addresses.
	*/
	cbd_t	*rx_bd_base;		/* Address of Rx and Tx buffers. */
	cbd_t	*tx_bd_base;
	cbd_t	*cur_rx, *cur_tx;		/* The next free ring entry */
	cbd_t	*dirty_tx;	/* The ring entries to be free()ed. */
	scc_t	*sccp;
	struct	net_device_stats stats;
	uint	tx_full;
	uint	tx_ring_len;
	spinlock_t lock;

#ifdef	CONFIG_USE_MDIO
	uint	phy_id;
	uint	phy_id_done;
	uint	phy_status;
	uint	phy_speed;
	phy_info_t	*phy;
	struct tq_struct phy_task;

	uint	sequence_done;

	uint	phy_addr;
#endif	/* CONFIG_USE_MDIO */

	int	link;
	int	old_link;
	int	full_duplex;

#ifdef CONFIG_FEC_PACKETHOOK
	unsigned long	ph_lock;
	fec_ph_func	*ph_rxhandler;
	fec_ph_func	*ph_txhandler;
	__u16		ph_proto;
	volatile __u32	*ph_regaddr;
	void 		*ph_priv;
#endif
};

static int fec_enet_open(struct net_device *dev);
static int fec_enet_start_xmit(struct sk_buff *skb, struct net_device *dev);
#ifdef	CONFIG_USE_MDIO
static void fec_enet_mii(struct net_device *dev);
#endif	/* CONFIG_USE_MDIO */
static void fec_enet_interrupt(int irq, void * dev_id, struct pt_regs * regs);
#ifdef CONFIG_FEC_PACKETHOOK
static void  fec_enet_tx(struct net_device *dev, __u32 regval);
static void  fec_enet_rx(struct net_device *dev, __u32 regval);
#else
static void  fec_enet_tx(struct net_device *dev);
static void  fec_enet_rx(struct net_device *dev);
#endif
static int fec_enet_close(struct net_device *dev);
static struct net_device_stats *fec_enet_get_stats(struct net_device *dev);
static void set_multicast_list(struct net_device *dev);
static void fec_restart(struct net_device *dev, int duplex);
static void fec_stop(struct net_device *dev);
static	ushort	my_enet_addr[3];

#ifdef	CONFIG_USE_MDIO
/* MII processing.  We keep this as simple as possible.  Requests are
 * placed on the list (if there is room).  When the request is finished
 * by the MII, an optional function may be called.
 */
typedef struct mii_list {
	uint	mii_regval;
	void	(*mii_func)(uint val, struct net_device *dev);
	struct	mii_list *mii_next;
} mii_list_t;

#define		NMII	20
mii_list_t	mii_cmds[NMII];
mii_list_t	*mii_free;
mii_list_t	*mii_head;
mii_list_t	*mii_tail;

static int	mii_queue(struct net_device *dev, int request,
				void (*func)(uint, struct net_device *));

/* Make MII read/write commands for the FEC.
*/
#define mk_mii_read(REG)	(0x60020000 | ((REG & 0x1f) << 18))
#define mk_mii_write(REG, VAL)	(0x50020000 | ((REG & 0x1f) << 18) | \
						(VAL & 0xffff))
#define mk_mii_end	0
#endif	/* CONFIG_USE_MDIO */

/* Transmitter timeout.
*/
#define TX_TIMEOUT (2*HZ)

#ifdef	CONFIG_USE_MDIO
/* Register definitions for the PHY.
*/

#define MII_REG_CR          0  /* Control Register                         */
#define MII_REG_SR          1  /* Status Register                          */
#define MII_REG_PHYIR1      2  /* PHY Identification Register 1            */
#define MII_REG_PHYIR2      3  /* PHY Identification Register 2            */
#define MII_REG_ANAR        4  /* A-N Advertisement Register               */
#define MII_REG_ANLPAR      5  /* A-N Link Partner Ability Register        */
#define MII_REG_ANER        6  /* A-N Expansion Register                   */
#define MII_REG_ANNPTR      7  /* A-N Next Page Transmit Register          */
#define MII_REG_ANLPRNPR    8  /* A-N Link Partner Received Next Page Reg. */

/* values for phy_status */

#define PHY_CONF_ANE	0x0001  /* 1 auto-negotiation enabled */
#define PHY_CONF_LOOP	0x0002  /* 1 loopback mode enabled */
#define PHY_CONF_SPMASK	0x00f0  /* mask for speed */
#define PHY_CONF_10HDX	0x0010  /* 10 Mbit half duplex supported */
#define PHY_CONF_10FDX	0x0020  /* 10 Mbit full duplex supported */
#define PHY_CONF_100HDX	0x0040  /* 100 Mbit half duplex supported */
#define PHY_CONF_100FDX	0x0080  /* 100 Mbit full duplex supported */

#define PHY_STAT_LINK	0x0100  /* 1 up - 0 down */
#define PHY_STAT_FAULT	0x0200  /* 1 remote fault */
#define PHY_STAT_ANC	0x0400  /* 1 auto-negotiation complete	*/
#define PHY_STAT_SPMASK	0xf000  /* mask for speed */
#define PHY_STAT_10HDX	0x1000  /* 10 Mbit half duplex selected	*/
#define PHY_STAT_10FDX	0x2000  /* 10 Mbit full duplex selected	*/
#define PHY_STAT_100HDX	0x4000  /* 100 Mbit half duplex selected */
#define PHY_STAT_100FDX	0x8000  /* 100 Mbit full duplex selected */
#endif	/* CONFIG_USE_MDIO */

#ifdef CONFIG_FEC_PACKETHOOK
int
fec_register_ph(struct net_device *dev, fec_ph_func *rxfun, fec_ph_func *txfun,
		__u16 proto, volatile __u32 *regaddr, void *priv)
{
	struct fec_enet_private *fep;
	int retval = 0;

	fep = dev->priv;

	if (test_and_set_bit(0, (void*)&fep->ph_lock) != 0) {
		/* Someone is messing with the packet hook */
		return -EAGAIN;
	}
	if (fep->ph_rxhandler != NULL || fep->ph_txhandler != NULL) {
		retval = -EBUSY;
		goto out;
	}
	fep->ph_rxhandler = rxfun;
	fep->ph_txhandler = txfun;
	fep->ph_proto = proto;
	fep->ph_regaddr = regaddr;
	fep->ph_priv = priv;

	out:
	fep->ph_lock = 0;

	return retval;
}


int
fec_unregister_ph(struct net_device *dev)
{
	struct fec_enet_private *fep;
	int retval = 0;

	fep = dev->priv;

	if (test_and_set_bit(0, (void*)&fep->ph_lock) != 0) {
		/* Someone is messing with the packet hook */
		return -EAGAIN;
	}

	fep->ph_rxhandler = fep->ph_txhandler = NULL;
	fep->ph_proto = 0;
	fep->ph_regaddr = NULL;
	fep->ph_priv = NULL;

	fep->ph_lock = 0;

	return retval;
}

EXPORT_SYMBOL(fec_register_ph);
EXPORT_SYMBOL(fec_unregister_ph);

#endif /* CONFIG_FEC_PACKETHOOK */

static int
fec_enet_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct fec_enet_private *fep;
	volatile fec_t	*fecp;
	volatile cbd_t	*bdp;

	fep = dev->priv;
	fecp = (volatile fec_t*)dev->base_addr;

	if (!fep->link) {
		/* Link is down or autonegotiation is in progress. */
		return 1;
	}

	/* Fill in a Tx ring entry */
	bdp = fep->cur_tx;

#ifndef final_version
	if (bdp->cbd_sc & BD_ENET_TX_READY) {
		/* Ooops.  All transmit buffers are full.  Bail out.
		 * This should not happen, since dev->tbusy should be set.
		 */
		printk("%s: tx queue full!.\n", dev->name);
		return 1;
	}
#endif

	/* Clear all of the status flags.
	 */
	bdp->cbd_sc &= ~BD_ENET_TX_STATS;

	/* Set buffer length and buffer pointer.
	*/
	bdp->cbd_bufaddr = __pa(skb->data);
	bdp->cbd_datlen = skb->len;

	/* Save skb pointer.
	*/
	fep->tx_skbuff[fep->skb_cur] = skb;

	fep->stats.tx_bytes += skb->len;
	fep->skb_cur = (fep->skb_cur+1) & TX_RING_MOD_MASK;

#ifdef CONFIG_FEC_SUPPORT_SG
	if (skb_shinfo(skb)->nr_frags > 0) {
		/* Put additional fragments in seperate buffers */

		skb_frag_t *frag = skb_shinfo(skb)->frags;
		volatile cbd_t *fbdp = bdp;
		int i;

		/* Clear LAST flag */
		bdp->cbd_sc &= ~(BD_ENET_TX_INTR|BD_ENET_TX_LAST|BD_ENET_TX_TC);

		/* Note: skb->len is total length including all fragments */
		bdp->cbd_datlen -= skb->data_len;
		flush_dcache_range((unsigned long)skb->data,
		                   (unsigned long)skb->data + skb->len - skb->data_len);

		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++, frag++) {
			unsigned long faddr = (unsigned long) page_address(frag->page) + frag->page_offset;
			unsigned long flen = frag->size;

			/* Get next BD, wrap around end */
			if (fbdp->cbd_sc & BD_ENET_TX_WRAP)
				fbdp = fep->tx_bd_base;
			else
				fbdp++;
#ifndef final_version
			if (fbdp->cbd_sc & BD_ENET_TX_READY)
				printk(KERN_CRIT "fec: rhaaa: tx BD ring full\n");
#endif
			/* Clear all of the status flags. */
			fbdp->cbd_sc &= ~( BD_ENET_TX_STATS | BD_ENET_TX_INTR
			                 | BD_ENET_TX_LAST | BD_ENET_TX_TC );

			/* Set buffer length and buffer pointer. */
			fbdp->cbd_bufaddr = __pa(faddr);
			fbdp->cbd_datlen = flen;

			/* Push the data cache. */
			flush_dcache_range(faddr, faddr + flen);
		}
	} else /* WATCH OUT FOR THIS ELSE */
#endif
	/* Push the data cache so the CPM does not get stale memory
	 * data.
	 */
	flush_dcache_range((unsigned long)skb->data,
			   (unsigned long)skb->data + skb->len);
/* END IF FRAGMENTS */

	spin_lock_irq(&fep->lock);

	/* Send it on its way.  Tell FEC its ready, interrupt when done,
	 * its the last BD of the frame, and to put the CRC on the end.
	 */

#ifdef CONFIG_FEC_SUPPORT_SG
	if (skb_shinfo(skb)->nr_frags > 0) {
		int i;
		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
			bdp->cbd_sc |= BD_ENET_TX_READY;
			if (bdp->cbd_sc & BD_ENET_TX_WRAP)
				bdp = fep->tx_bd_base;
			else
				bdp++;
			fep->tx_ring_len++;
		}
	}
#endif
	bdp->cbd_sc |= (BD_ENET_TX_READY | BD_ENET_TX_INTR
			| BD_ENET_TX_LAST | BD_ENET_TX_TC);

	dev->trans_start = jiffies;

	/* Trigger transmission start */
	fecp->fec_x_des_active = 0x01000000;

	/* If this was the last BD in the ring, start at the beginning again.
	*/
	if (bdp->cbd_sc & BD_ENET_TX_WRAP) {
		bdp = fep->tx_bd_base;
	} else {
		bdp++;
	}
	fep->tx_ring_len++;

	if (bdp->cbd_sc & BD_ENET_TX_READY)
		fep->tx_full = 1;

#ifdef CONFIG_FEC_SUPPORT_SG
	if (fep->tx_ring_len + MAX_SKB_FRAGS >= TX_RING_SIZE)
#else
	if (fep->tx_ring_len >= TX_RING_SIZE)
#endif
		netif_stop_queue(dev);

	fep->cur_tx = (cbd_t *)bdp;

	spin_unlock_irq(&fep->lock);

	return 0;
}

static void
fec_timeout(struct net_device *dev)
{
	struct fec_enet_private *fep = dev->priv;

	printk("%s: transmit timed out.\n", dev->name);
	fep->stats.tx_errors++;