tmp_suning_uos_patched/drivers/net/sunbmac.c

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/* $Id: sunbmac.c,v 1.30 2002/01/15 06:48:55 davem Exp $
* sunbmac.c: Driver for Sparc BigMAC 100baseT ethernet adapters.
*
* Copyright (C) 1997, 1998, 1999, 2003 David S. Miller (davem@redhat.com)
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/crc32.h>
#include <linux/errno.h>
#include <linux/ethtool.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/bitops.h>
#include <asm/auxio.h>
#include <asm/byteorder.h>
#include <asm/dma.h>
#include <asm/idprom.h>
#include <asm/io.h>
#include <asm/openprom.h>
#include <asm/oplib.h>
#include <asm/pgtable.h>
#include <asm/sbus.h>
#include <asm/system.h>
#include "sunbmac.h"
#define DRV_NAME "sunbmac"
#define DRV_VERSION "2.0"
#define DRV_RELDATE "11/24/03"
#define DRV_AUTHOR "David S. Miller (davem@redhat.com)"
static char version[] =
DRV_NAME ".c:v" DRV_VERSION " " DRV_RELDATE " " DRV_AUTHOR "\n";
MODULE_VERSION(DRV_VERSION);
MODULE_AUTHOR(DRV_AUTHOR);
MODULE_DESCRIPTION("Sun BigMAC 100baseT ethernet driver");
MODULE_LICENSE("GPL");
#undef DEBUG_PROBE
#undef DEBUG_TX
#undef DEBUG_IRQ
#ifdef DEBUG_PROBE
#define DP(x) printk x
#else
#define DP(x)
#endif
#ifdef DEBUG_TX
#define DTX(x) printk x
#else
#define DTX(x)
#endif
#ifdef DEBUG_IRQ
#define DIRQ(x) printk x
#else
#define DIRQ(x)
#endif
#define DEFAULT_JAMSIZE 4 /* Toe jam */
#define QEC_RESET_TRIES 200
static int qec_global_reset(void __iomem *gregs)
{
int tries = QEC_RESET_TRIES;
sbus_writel(GLOB_CTRL_RESET, gregs + GLOB_CTRL);
while (--tries) {
if (sbus_readl(gregs + GLOB_CTRL) & GLOB_CTRL_RESET) {
udelay(20);
continue;
}
break;
}
if (tries)
return 0;
printk(KERN_ERR "BigMAC: Cannot reset the QEC.\n");
return -1;
}
static void qec_init(struct bigmac *bp)
{
void __iomem *gregs = bp->gregs;
struct sbus_dev *qec_sdev = bp->qec_sdev;
u8 bsizes = bp->bigmac_bursts;
u32 regval;
/* 64byte bursts do not work at the moment, do
* not even try to enable them. -DaveM
*/
if (bsizes & DMA_BURST32)
regval = GLOB_CTRL_B32;
else
regval = GLOB_CTRL_B16;
sbus_writel(regval | GLOB_CTRL_BMODE, gregs + GLOB_CTRL);
sbus_writel(GLOB_PSIZE_2048, gregs + GLOB_PSIZE);
/* All of memsize is given to bigmac. */
sbus_writel(qec_sdev->reg_addrs[1].reg_size,
gregs + GLOB_MSIZE);
/* Half to the transmitter, half to the receiver. */
sbus_writel(qec_sdev->reg_addrs[1].reg_size >> 1,
gregs + GLOB_TSIZE);
sbus_writel(qec_sdev->reg_addrs[1].reg_size >> 1,
gregs + GLOB_RSIZE);
}
#define TX_RESET_TRIES 32
#define RX_RESET_TRIES 32
static void bigmac_tx_reset(void __iomem *bregs)
{
int tries = TX_RESET_TRIES;
sbus_writel(0, bregs + BMAC_TXCFG);
/* The fifo threshold bit is read-only and does
* not clear. -DaveM
*/
while ((sbus_readl(bregs + BMAC_TXCFG) & ~(BIGMAC_TXCFG_FIFO)) != 0 &&
--tries != 0)
udelay(20);
if (!tries) {
printk(KERN_ERR "BIGMAC: Transmitter will not reset.\n");
printk(KERN_ERR "BIGMAC: tx_cfg is %08x\n",
sbus_readl(bregs + BMAC_TXCFG));
}
}
static void bigmac_rx_reset(void __iomem *bregs)
{
int tries = RX_RESET_TRIES;
sbus_writel(0, bregs + BMAC_RXCFG);
while (sbus_readl(bregs + BMAC_RXCFG) && --tries)
udelay(20);
if (!tries) {
printk(KERN_ERR "BIGMAC: Receiver will not reset.\n");
printk(KERN_ERR "BIGMAC: rx_cfg is %08x\n",
sbus_readl(bregs + BMAC_RXCFG));
}
}
/* Reset the transmitter and receiver. */
static void bigmac_stop(struct bigmac *bp)
{
bigmac_tx_reset(bp->bregs);
bigmac_rx_reset(bp->bregs);
}
static void bigmac_get_counters(struct bigmac *bp, void __iomem *bregs)
{
struct net_device_stats *stats = &bp->enet_stats;
stats->rx_crc_errors += sbus_readl(bregs + BMAC_RCRCECTR);
sbus_writel(0, bregs + BMAC_RCRCECTR);
stats->rx_frame_errors += sbus_readl(bregs + BMAC_UNALECTR);
sbus_writel(0, bregs + BMAC_UNALECTR);
stats->rx_length_errors += sbus_readl(bregs + BMAC_GLECTR);
sbus_writel(0, bregs + BMAC_GLECTR);
stats->tx_aborted_errors += sbus_readl(bregs + BMAC_EXCTR);
stats->collisions +=
(sbus_readl(bregs + BMAC_EXCTR) +
sbus_readl(bregs + BMAC_LTCTR));
sbus_writel(0, bregs + BMAC_EXCTR);
sbus_writel(0, bregs + BMAC_LTCTR);
}
static void bigmac_clean_rings(struct bigmac *bp)
{
int i;
for (i = 0; i < RX_RING_SIZE; i++) {
if (bp->rx_skbs[i] != NULL) {
dev_kfree_skb_any(bp->rx_skbs[i]);
bp->rx_skbs[i] = NULL;
}
}
for (i = 0; i < TX_RING_SIZE; i++) {
if (bp->tx_skbs[i] != NULL) {
dev_kfree_skb_any(bp->tx_skbs[i]);
bp->tx_skbs[i] = NULL;
}
}
}
static void bigmac_init_rings(struct bigmac *bp, int from_irq)
{
struct bmac_init_block *bb = bp->bmac_block;
struct net_device *dev = bp->dev;
int i;
gfp_t gfp_flags = GFP_KERNEL;
if (from_irq || in_interrupt())
gfp_flags = GFP_ATOMIC;
bp->rx_new = bp->rx_old = bp->tx_new = bp->tx_old = 0;
/* Free any skippy bufs left around in the rings. */
bigmac_clean_rings(bp);
/* Now get new skbufs for the receive ring. */
for (i = 0; i < RX_RING_SIZE; i++) {
struct sk_buff *skb;
skb = big_mac_alloc_skb(RX_BUF_ALLOC_SIZE, gfp_flags);
if (!skb)
continue;
bp->rx_skbs[i] = skb;
skb->dev = dev;
/* Because we reserve afterwards. */
skb_put(skb, ETH_FRAME_LEN);
skb_reserve(skb, 34);
bb->be_rxd[i].rx_addr =
sbus_map_single(bp->bigmac_sdev, skb->data,
RX_BUF_ALLOC_SIZE - 34,
SBUS_DMA_FROMDEVICE);
bb->be_rxd[i].rx_flags =
(RXD_OWN | ((RX_BUF_ALLOC_SIZE - 34) & RXD_LENGTH));
}
for (i = 0; i < TX_RING_SIZE; i++)
bb->be_txd[i].tx_flags = bb->be_txd[i].tx_addr = 0;
}
#define MGMT_CLKON (MGMT_PAL_INT_MDIO|MGMT_PAL_EXT_MDIO|MGMT_PAL_OENAB|MGMT_PAL_DCLOCK)
#define MGMT_CLKOFF (MGMT_PAL_INT_MDIO|MGMT_PAL_EXT_MDIO|MGMT_PAL_OENAB)
static void idle_transceiver(void __iomem *tregs)
{
int i = 20;
while (i--) {
sbus_writel(MGMT_CLKOFF, tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
sbus_writel(MGMT_CLKON, tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
}
}
static void write_tcvr_bit(struct bigmac *bp, void __iomem *tregs, int bit)
{
if (bp->tcvr_type == internal) {
bit = (bit & 1) << 3;
sbus_writel(bit | (MGMT_PAL_OENAB | MGMT_PAL_EXT_MDIO),
tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
sbus_writel(bit | MGMT_PAL_OENAB | MGMT_PAL_EXT_MDIO | MGMT_PAL_DCLOCK,
tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
} else if (bp->tcvr_type == external) {
bit = (bit & 1) << 2;
sbus_writel(bit | MGMT_PAL_INT_MDIO | MGMT_PAL_OENAB,
tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
sbus_writel(bit | MGMT_PAL_INT_MDIO | MGMT_PAL_OENAB | MGMT_PAL_DCLOCK,
tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
} else {
printk(KERN_ERR "write_tcvr_bit: No transceiver type known!\n");
}
}
static int read_tcvr_bit(struct bigmac *bp, void __iomem *tregs)
{
int retval = 0;
if (bp->tcvr_type == internal) {
sbus_writel(MGMT_PAL_EXT_MDIO, tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
sbus_writel(MGMT_PAL_EXT_MDIO | MGMT_PAL_DCLOCK,
tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
retval = (sbus_readl(tregs + TCVR_MPAL) & MGMT_PAL_INT_MDIO) >> 3;
} else if (bp->tcvr_type == external) {
sbus_writel(MGMT_PAL_INT_MDIO, tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
sbus_writel(MGMT_PAL_INT_MDIO | MGMT_PAL_DCLOCK, tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
retval = (sbus_readl(tregs + TCVR_MPAL) & MGMT_PAL_EXT_MDIO) >> 2;
} else {
printk(KERN_ERR "read_tcvr_bit: No transceiver type known!\n");
}
return retval;
}
static int read_tcvr_bit2(struct bigmac *bp, void __iomem *tregs)
{
int retval = 0;
if (bp->tcvr_type == internal) {
sbus_writel(MGMT_PAL_EXT_MDIO, tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
retval = (sbus_readl(tregs + TCVR_MPAL) & MGMT_PAL_INT_MDIO) >> 3;
sbus_writel(MGMT_PAL_EXT_MDIO | MGMT_PAL_DCLOCK, tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
} else if (bp->tcvr_type == external) {
sbus_writel(MGMT_PAL_INT_MDIO, tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
retval = (sbus_readl(tregs + TCVR_MPAL) & MGMT_PAL_EXT_MDIO) >> 2;
sbus_writel(MGMT_PAL_INT_MDIO | MGMT_PAL_DCLOCK, tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
} else {
printk(KERN_ERR "read_tcvr_bit2: No transceiver type known!\n");
}
return retval;
}
static void put_tcvr_byte(struct bigmac *bp,
void __iomem *tregs,
unsigned int byte)
{
int shift = 4;
do {
write_tcvr_bit(bp, tregs, ((byte >> shift) & 1));
shift -= 1;
} while (shift >= 0);
}
static void bigmac_tcvr_write(struct bigmac *bp, void __iomem *tregs,
int reg, unsigned short val)
{
int shift;
reg &= 0xff;
val &= 0xffff;
switch(bp->tcvr_type) {
case internal:
case external:
break;
default:
printk(KERN_ERR "bigmac_tcvr_read: Whoops, no known transceiver type.\n");
return;
};
idle_transceiver(tregs);
write_tcvr_bit(bp, tregs, 0);
write_tcvr_bit(bp, tregs, 1);
write_tcvr_bit(bp, tregs, 0);
write_tcvr_bit(bp, tregs, 1);
put_tcvr_byte(bp, tregs,
((bp->tcvr_type == internal) ?
BIGMAC_PHY_INTERNAL : BIGMAC_PHY_EXTERNAL));
put_tcvr_byte(bp, tregs, reg);
write_tcvr_bit(bp, tregs, 1);
write_tcvr_bit(bp, tregs, 0);
shift = 15;
do {
write_tcvr_bit(bp, tregs, (val >> shift) & 1);
shift -= 1;
} while (shift >= 0);
}
static unsigned short bigmac_tcvr_read(struct bigmac *bp,
void __iomem *tregs,
int reg)
{
unsigned short retval = 0;
reg &= 0xff;
switch(bp->tcvr_type) {
case internal:
case external:
break;
default:
printk(KERN_ERR "bigmac_tcvr_read: Whoops, no known transceiver type.\n");
return 0xffff;
};
idle_transceiver(tregs);
write_tcvr_bit(bp, tregs, 0);
write_tcvr_bit(bp, tregs, 1);
write_tcvr_bit(bp, tregs, 1);
write_tcvr_bit(bp, tregs, 0);
put_tcvr_byte(bp, tregs,
((bp->tcvr_type == internal) ?
BIGMAC_PHY_INTERNAL : BIGMAC_PHY_EXTERNAL));
put_tcvr_byte(bp, tregs, reg);
if (bp->tcvr_type == external) {
int shift = 15;
(void) read_tcvr_bit2(bp, tregs);
(void) read_tcvr_bit2(bp, tregs);
do {
int tmp;
tmp = read_tcvr_bit2(bp, tregs);
retval |= ((tmp & 1) << shift);
shift -= 1;
} while (shift >= 0);
(void) read_tcvr_bit2(bp, tregs);
(void) read_tcvr_bit2(bp, tregs);
(void) read_tcvr_bit2(bp, tregs);
} else {
int shift = 15;
(void) read_tcvr_bit(bp, tregs);
(void) read_tcvr_bit(bp, tregs);
do {
int tmp;
tmp = read_tcvr_bit(bp, tregs);
retval |= ((tmp & 1) << shift);
shift -= 1;
} while (shift >= 0);
(void) read_tcvr_bit(bp, tregs);
(void) read_tcvr_bit(bp, tregs);
(void) read_tcvr_bit(bp, tregs);
}
return retval;
}
static void bigmac_tcvr_init(struct bigmac *bp)
{
void __iomem *tregs = bp->tregs;
u32 mpal;
idle_transceiver(tregs);
sbus_writel(MGMT_PAL_INT_MDIO | MGMT_PAL_EXT_MDIO | MGMT_PAL_DCLOCK,
tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
/* Only the bit for the present transceiver (internal or
* external) will stick, set them both and see what stays.
*/
sbus_writel(MGMT_PAL_INT_MDIO | MGMT_PAL_EXT_MDIO, tregs + TCVR_MPAL);
sbus_readl(tregs + TCVR_MPAL);
udelay(20);
mpal = sbus_readl(tregs + TCVR_MPAL);
if (mpal & MGMT_PAL_EXT_MDIO) {
bp->tcvr_type = external;
sbus_writel(~(TCVR_PAL_EXTLBACK | TCVR_PAL_MSENSE | TCVR_PAL_LTENABLE),
tregs + TCVR_TPAL);
sbus_readl(tregs + TCVR_TPAL);
} else if (mpal & MGMT_PAL_INT_MDIO) {
bp->tcvr_type = internal;
sbus_writel(~(TCVR_PAL_SERIAL | TCVR_PAL_EXTLBACK |
TCVR_PAL_MSENSE | TCVR_PAL_LTENABLE),
tregs + TCVR_TPAL);
sbus_readl(tregs + TCVR_TPAL);
} else {
printk(KERN_ERR "BIGMAC: AIEEE, neither internal nor "
"external MDIO available!\n");
printk(KERN_ERR "BIGMAC: mgmt_pal[%08x] tcvr_pal[%08x]\n",
sbus_readl(tregs + TCVR_MPAL),
sbus_readl(tregs + TCVR_TPAL));
}
}
static int bigmac_init_hw(struct bigmac *, int);
static int try_next_permutation(struct bigmac *bp, void __iomem *tregs)
{
if (bp->sw_bmcr & BMCR_SPEED100) {
int timeout;
/* Reset the PHY. */
bp->sw_bmcr = (BMCR_ISOLATE | BMCR_PDOWN | BMCR_LOOPBACK);
bigmac_tcvr_write(bp, tregs, BIGMAC_BMCR, bp->sw_bmcr);
bp->sw_bmcr = (BMCR_RESET);
bigmac_tcvr_write(bp, tregs, BIGMAC_BMCR, bp->sw_bmcr);
timeout = 64;
while (--timeout) {
bp->sw_bmcr = bigmac_tcvr_read(bp, tregs, BIGMAC_BMCR);
if ((bp->sw_bmcr & BMCR_RESET) == 0)
break;
udelay(20);
}
if (timeout == 0)
printk(KERN_ERR "%s: PHY reset failed.\n", bp->dev->name);
bp->sw_bmcr = bigmac_tcvr_read(bp, tregs, BIGMAC_BMCR);
/* Now we try 10baseT. */
bp->sw_bmcr &= ~(BMCR_SPEED100);
bigmac_tcvr_write(bp, tregs, BIGMAC_BMCR, bp->sw_bmcr);
return 0;
}
/* We've tried them all. */
return -1;
}
static void bigmac_timer(unsigned long data)
{
struct bigmac *bp = (struct bigmac *) data;
void __iomem *tregs = bp->tregs;
int restart_timer = 0;
bp->timer_ticks++;
if (bp->timer_state == ltrywait) {
bp->sw_bmsr = bigmac_tcvr_read(bp, tregs, BIGMAC_BMSR);
bp->sw_bmcr = bigmac_tcvr_read(bp, tregs, BIGMAC_BMCR);
if (bp->sw_bmsr & BMSR_LSTATUS) {
printk(KERN_INFO "%s: Link is now up at %s.\n",
bp->dev->name,
(bp->sw_bmcr & BMCR_SPEED100) ?
"100baseT" : "10baseT");
bp->timer_state = asleep;
restart_timer = 0;
} else {
if (bp->timer_ticks >= 4) {
int ret;
ret = try_next_permutation(bp, tregs);
if (ret == -1) {
printk(KERN_ERR "%s: Link down, cable problem?\n",
bp->dev->name);
ret = bigmac_init_hw(bp, 0);
if (ret) {
printk(KERN_ERR "%s: Error, cannot re-init the "
"BigMAC.\n", bp->dev->name);
}
return;
}
bp->timer_ticks = 0;
restart_timer = 1;
} else {
restart_timer = 1;
}
}
} else {
/* Can't happens.... */
printk(KERN_ERR "%s: Aieee, link timer is asleep but we got one anyways!\n",
bp->dev->name);
restart_timer = 0;
bp->timer_ticks = 0;
bp->timer_state = asleep; /* foo on you */
}
if (restart_timer != 0) {
bp->bigmac_timer.expires = jiffies + ((12 * HZ)/10); /* 1.2 sec. */
add_timer(&bp->bigmac_timer);
}
}
/* Well, really we just force the chip into 100baseT then
* 10baseT, each time checking for a link status.
*/
static void bigmac_begin_auto_negotiation(struct bigmac *bp)
{
void __iomem *tregs = bp->tregs;
int timeout;
/* Grab new software copies of PHY registers. */
bp->sw_bmsr = bigmac_tcvr_read(bp, tregs, BIGMAC_BMSR);
bp->sw_bmcr = bigmac_tcvr_read(bp, tregs, BIGMAC_BMCR);
/* Reset the PHY. */
bp->sw_bmcr = (BMCR_ISOLATE | BMCR_PDOWN | BMCR_LOOPBACK);
bigmac_tcvr_write(bp, tregs, BIGMAC_BMCR, bp->sw_bmcr);
bp->sw_bmcr = (BMCR_RESET);
bigmac_tcvr_write(bp, tregs, BIGMAC_BMCR, bp->sw_bmcr);
timeout = 64;
while (--timeout) {
bp->sw_bmcr = bigmac_tcvr_read(bp, tregs, BIGMAC_BMCR);
if ((bp->sw_bmcr & BMCR_RESET) == 0)
break;
udelay(20);
}
if (timeout == 0)
printk(KERN_ERR "%s: PHY reset failed.\n", bp->dev->name);
bp->sw_bmcr = bigmac_tcvr_read(bp, tregs, BIGMAC_BMCR);
/* First we try 100baseT. */
bp->sw_bmcr |= BMCR_SPEED100;
bigmac_tcvr_write(bp, tregs, BIGMAC_BMCR, bp->sw_bmcr);
bp->timer_state = ltrywait;
bp->timer_ticks = 0;
bp->bigmac_timer.expires = jiffies + (12 * HZ) / 10;
bp->bigmac_timer.data = (unsigned long) bp;
bp->bigmac_timer.function = &bigmac_timer;
add_timer(&bp->bigmac_timer);
}
static int bigmac_init_hw(struct bigmac *bp, int from_irq)
{
void __iomem *gregs = bp->gregs;
void __iomem *cregs = bp->creg;
void __iomem *bregs = bp->bregs;
unsigned char *e = &bp->dev->dev_addr[0];
/* Latch current counters into statistics. */
bigmac_get_counters(bp, bregs);
/* Reset QEC. */
qec_global_reset(gregs);
/* Init QEC. */
qec_init(bp);
/* Alloc and reset the tx/rx descriptor chains. */
bigmac_init_rings(bp, from_irq);
/* Initialize the PHY. */
bigmac_tcvr_init(bp);
/* Stop transmitter and receiver. */
bigmac_stop(bp);
/* Set hardware ethernet address. */
sbus_writel(((e[4] << 8) | e[5]), bregs + BMAC_MACADDR2);
sbus_writel(((e[2] << 8) | e[3]), bregs + BMAC_MACADDR1);
sbus_writel(((e[0] << 8) | e[1]), bregs + BMAC_MACADDR0);
/* Clear the hash table until mc upload occurs. */
sbus_writel(0, bregs + BMAC_HTABLE3);
sbus_writel(0, bregs + BMAC_HTABLE2);
sbus_writel(0, bregs + BMAC_HTABLE1);
sbus_writel(0, bregs + BMAC_HTABLE0);
/* Enable Big Mac hash table filter. */
sbus_writel(BIGMAC_RXCFG_HENABLE | BIGMAC_RXCFG_FIFO,
bregs + BMAC_RXCFG);
udelay(20);
/* Ok, configure the Big Mac transmitter. */
sbus_writel(BIGMAC_TXCFG_FIFO, bregs + BMAC_TXCFG);
/* The HME docs recommend to use the 10LSB of our MAC here. */
sbus_writel(((e[5] | e[4] << 8) & 0x3ff),
bregs + BMAC_RSEED);
/* Enable the output drivers no matter what. */
sbus_writel(BIGMAC_XCFG_ODENABLE | BIGMAC_XCFG_RESV,
bregs + BMAC_XIFCFG);
/* Tell the QEC where the ring descriptors are. */
sbus_writel(bp->bblock_dvma + bib_offset(be_rxd, 0),
cregs + CREG_RXDS);
sbus_writel(bp->bblock_dvma + bib_offset(be_txd, 0),
cregs + CREG_TXDS);
/* Setup the FIFO pointers into QEC local memory. */
sbus_writel(0, cregs + CREG_RXRBUFPTR);
sbus_writel(0, cregs + CREG_RXWBUFPTR);
sbus_writel(sbus_readl(gregs + GLOB_RSIZE),
cregs + CREG_TXRBUFPTR);
sbus_writel(sbus_readl(gregs + GLOB_RSIZE),
cregs + CREG_TXWBUFPTR);
/* Tell bigmac what interrupts we don't want to hear about. */
sbus_writel(BIGMAC_IMASK_GOTFRAME | BIGMAC_IMASK_SENTFRAME,
bregs + BMAC_IMASK);
/* Enable the various other irq's. */
sbus_writel(0, cregs + CREG_RIMASK);
sbus_writel(0, cregs + CREG_TIMASK);
sbus_writel(0, cregs + CREG_QMASK);
sbus_writel(0, cregs + CREG_BMASK);
/* Set jam size to a reasonable default. */
sbus_writel(DEFAULT_JAMSIZE, bregs + BMAC_JSIZE);
/* Clear collision counter. */
sbus_writel(0, cregs + CREG_CCNT);
/* Enable transmitter and receiver. */
sbus_writel(sbus_readl(bregs + BMAC_TXCFG) | BIGMAC_TXCFG_ENABLE,
bregs + BMAC_TXCFG);
sbus_writel(sbus_readl(bregs + BMAC_RXCFG) | BIGMAC_RXCFG_ENABLE,
bregs + BMAC_RXCFG);
/* Ok, start detecting link speed/duplex. */
bigmac_begin_auto_negotiation(bp);
/* Success. */
return 0;
}
/* Error interrupts get sent here. */
static void bigmac_is_medium_rare(struct bigmac *bp, u32 qec_status, u32 bmac_status)
{
printk(KERN_ERR "bigmac_is_medium_rare: ");
if (qec_status & (GLOB_STAT_ER | GLOB_STAT_BM)) {
if (qec_status & GLOB_STAT_ER)
printk("QEC_ERROR, ");
if (qec_status & GLOB_STAT_BM)
printk("QEC_BMAC_ERROR, ");
}
if (bmac_status & CREG_STAT_ERRORS) {
if (bmac_status & CREG_STAT_BERROR)
printk("BMAC_ERROR, ");
if (bmac_status & CREG_STAT_TXDERROR)
printk("TXD_ERROR, ");
if (bmac_status & CREG_STAT_TXLERR)
printk("TX_LATE_ERROR, ");
if (bmac_status & CREG_STAT_TXPERR)
printk("TX_PARITY_ERROR, ");
if (bmac_status & CREG_STAT_TXSERR)
printk("TX_SBUS_ERROR, ");
if (bmac_status & CREG_STAT_RXDROP)
printk("RX_DROP_ERROR, ");
if (bmac_status & CREG_STAT_RXSMALL)
printk("RX_SMALL_ERROR, ");
if (bmac_status & CREG_STAT_RXLERR)
printk("RX_LATE_ERROR, ");
if (bmac_status & CREG_STAT_RXPERR)
printk("RX_PARITY_ERROR, ");
if (bmac_status & CREG_STAT_RXSERR)
printk("RX_SBUS_ERROR, ");
}
printk(" RESET\n");
bigmac_init_hw(bp, 1);
}
/* BigMAC transmit complete service routines. */
static void bigmac_tx(struct bigmac *bp)
{
struct be_txd *txbase = &bp->bmac_block->be_txd[0];
struct net_device *dev = bp->dev;
int elem;
spin_lock(&bp->lock);
elem = bp->tx_old;
DTX(("bigmac_tx: tx_old[%d] ", elem));
while (elem != bp->tx_new) {
struct sk_buff *skb;
struct be_txd *this = &txbase[elem];
DTX(("this(%p) [flags(%08x)addr(%08x)]",
this, this->tx_flags, this->tx_addr));
if (this->tx_flags & TXD_OWN)
break;
skb = bp->tx_skbs[elem];
bp->enet_stats.tx_packets++;
bp->enet_stats.tx_bytes += skb->len;
sbus_unmap_single(bp->bigmac_sdev,
this->tx_addr, skb->len,
SBUS_DMA_TODEVICE);
DTX(("skb(%p) ", skb));
bp->tx_skbs[elem] = NULL;
dev_kfree_skb_irq(skb);
elem = NEXT_TX(elem);
}
DTX((" DONE, tx_old=%d\n", elem));
bp->tx_old = elem;
if (netif_queue_stopped(dev) &&
TX_BUFFS_AVAIL(bp) > 0)
netif_wake_queue(bp->dev);
spin_unlock(&bp->lock);
}
/* BigMAC receive complete service routines. */
static void bigmac_rx(struct bigmac *bp)
{
struct be_rxd *rxbase = &bp->bmac_block->be_rxd[0];
struct be_rxd *this;
int elem = bp->rx_new, drops = 0;
u32 flags;
this = &rxbase[elem];
while (!((flags = this->rx_flags) & RXD_OWN)) {
struct sk_buff *skb;
int len = (flags & RXD_LENGTH); /* FCS not included */
/* Check for errors. */
if (len < ETH_ZLEN) {
bp->enet_stats.rx_errors++;
bp->enet_stats.rx_length_errors++;
drop_it:
/* Return it to the BigMAC. */
bp->enet_stats.rx_dropped++;
this->rx_flags =
(RXD_OWN | ((RX_BUF_ALLOC_SIZE - 34) & RXD_LENGTH));
goto next;
}
skb = bp->rx_skbs[elem];
if (len > RX_COPY_THRESHOLD) {
struct sk_buff *new_skb;
/* Now refill the entry, if we can. */
new_skb = big_mac_alloc_skb(RX_BUF_ALLOC_SIZE, GFP_ATOMIC);
if (new_skb == NULL) {
drops++;
goto drop_it;
}
sbus_unmap_single(bp->bigmac_sdev,
this->rx_addr,
RX_BUF_ALLOC_SIZE - 34,
SBUS_DMA_FROMDEVICE);
bp->rx_skbs[elem] = new_skb;
new_skb->dev = bp->dev;
skb_put(new_skb, ETH_FRAME_LEN);
skb_reserve(new_skb, 34);
this->rx_addr = sbus_map_single(bp->bigmac_sdev,
new_skb->data,
RX_BUF_ALLOC_SIZE - 34,
SBUS_DMA_FROMDEVICE);
this->rx_flags =
(RXD_OWN | ((RX_BUF_ALLOC_SIZE - 34) & RXD_LENGTH));
/* Trim the original skb for the netif. */
skb_trim(skb, len);
} else {
struct sk_buff *copy_skb = dev_alloc_skb(len + 2);
if (copy_skb == NULL) {
drops++;
goto drop_it;
}
skb_reserve(copy_skb, 2);
skb_put(copy_skb, len);
sbus_dma_sync_single_for_cpu(bp->bigmac_sdev,
this->rx_addr, len,
SBUS_DMA_FROMDEVICE);
skb_copy_to_linear_data(copy_skb, (unsigned char *)skb->data, len);
sbus_dma_sync_single_for_device(bp->bigmac_sdev,
this->rx_addr, len,
SBUS_DMA_FROMDEVICE);
/* Reuse original ring buffer. */
this->rx_flags =
(RXD_OWN | ((RX_BUF_ALLOC_SIZE - 34) & RXD_LENGTH));
skb = copy_skb;
}
/* No checksums done by the BigMAC ;-( */
skb->protocol = eth_type_trans(skb, bp->dev);
netif_rx(skb);
bp->dev->last_rx = jiffies;
bp->enet_stats.rx_packets++;
bp->enet_stats.rx_bytes += len;
next:
elem = NEXT_RX(elem);
this = &rxbase[elem];
}
bp->rx_new = elem;
if (drops)
printk(KERN_NOTICE "%s: Memory squeeze, deferring packet.\n", bp->dev->name);
}
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 21:55:46 +08:00
static irqreturn_t bigmac_interrupt(int irq, void *dev_id)
{
struct bigmac *bp = (struct bigmac *) dev_id;
u32 qec_status, bmac_status;
DIRQ(("bigmac_interrupt: "));
/* Latch status registers now. */
bmac_status = sbus_readl(bp->creg + CREG_STAT);
qec_status = sbus_readl(bp->gregs + GLOB_STAT);
DIRQ(("qec_status=%08x bmac_status=%08x\n", qec_status, bmac_status));
if ((qec_status & (GLOB_STAT_ER | GLOB_STAT_BM)) ||
(bmac_status & CREG_STAT_ERRORS))
bigmac_is_medium_rare(bp, qec_status, bmac_status);
if (bmac_status & CREG_STAT_TXIRQ)
bigmac_tx(bp);
if (bmac_status & CREG_STAT_RXIRQ)
bigmac_rx(bp);
return IRQ_HANDLED;
}
static int bigmac_open(struct net_device *dev)
{
struct bigmac *bp = (struct bigmac *) dev->priv;
int ret;
ret = request_irq(dev->irq, &bigmac_interrupt, IRQF_SHARED, dev->name, bp);
if (ret) {
printk(KERN_ERR "BIGMAC: Can't order irq %d to go.\n", dev->irq);
return ret;
}
init_timer(&bp->bigmac_timer);
ret = bigmac_init_hw(bp, 0);
if (ret)
free_irq(dev->irq, bp);
return ret;
}
static int bigmac_close(struct net_device *dev)
{
struct bigmac *bp = (struct bigmac *) dev->priv;
del_timer(&bp->bigmac_timer);
bp->timer_state = asleep;
bp->timer_ticks = 0;
bigmac_stop(bp);
bigmac_clean_rings(bp);
free_irq(dev->irq, bp);
return 0;
}
static void bigmac_tx_timeout(struct net_device *dev)
{
struct bigmac *bp = (struct bigmac *) dev->priv;
bigmac_init_hw(bp, 0);
netif_wake_queue(dev);
}
/* Put a packet on the wire. */
static int bigmac_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct bigmac *bp = (struct bigmac *) dev->priv;
int len, entry;
u32 mapping;
len = skb->len;
mapping = sbus_map_single(bp->bigmac_sdev, skb->data, len, SBUS_DMA_TODEVICE);
/* Avoid a race... */
spin_lock_irq(&bp->lock);
entry = bp->tx_new;
DTX(("bigmac_start_xmit: len(%d) entry(%d)\n", len, entry));
bp->bmac_block->be_txd[entry].tx_flags = TXD_UPDATE;
bp->tx_skbs[entry] = skb;
bp->bmac_block->be_txd[entry].tx_addr = mapping;
bp->bmac_block->be_txd[entry].tx_flags =
(TXD_OWN | TXD_SOP | TXD_EOP | (len & TXD_LENGTH));
bp->tx_new = NEXT_TX(entry);
if (TX_BUFFS_AVAIL(bp) <= 0)
netif_stop_queue(dev);
spin_unlock_irq(&bp->lock);
/* Get it going. */
sbus_writel(CREG_CTRL_TWAKEUP, bp->creg + CREG_CTRL);
dev->trans_start = jiffies;
return 0;
}
static struct net_device_stats *bigmac_get_stats(struct net_device *dev)
{
struct bigmac *bp = (struct bigmac *) dev->priv;
bigmac_get_counters(bp, bp->bregs);
return &bp->enet_stats;
}
static void bigmac_set_multicast(struct net_device *dev)
{
struct bigmac *bp = (struct bigmac *) dev->priv;
void __iomem *bregs = bp->bregs;
struct dev_mc_list *dmi = dev->mc_list;
char *addrs;
int i;
u32 tmp, crc;
/* Disable the receiver. The bit self-clears when
* the operation is complete.
*/
tmp = sbus_readl(bregs + BMAC_RXCFG);
tmp &= ~(BIGMAC_RXCFG_ENABLE);
sbus_writel(tmp, bregs + BMAC_RXCFG);
while ((sbus_readl(bregs + BMAC_RXCFG) & BIGMAC_RXCFG_ENABLE) != 0)
udelay(20);
if ((dev->flags & IFF_ALLMULTI) || (dev->mc_count > 64)) {
sbus_writel(0xffff, bregs + BMAC_HTABLE0);
sbus_writel(0xffff, bregs + BMAC_HTABLE1);
sbus_writel(0xffff, bregs + BMAC_HTABLE2);
sbus_writel(0xffff, bregs + BMAC_HTABLE3);
} else if (dev->flags & IFF_PROMISC) {
tmp = sbus_readl(bregs + BMAC_RXCFG);
tmp |= BIGMAC_RXCFG_PMISC;
sbus_writel(tmp, bregs + BMAC_RXCFG);
} else {
u16 hash_table[4];
for (i = 0; i < 4; i++)
hash_table[i] = 0;
for (i = 0; i < dev->mc_count; i++) {
addrs = dmi->dmi_addr;
dmi = dmi->next;
if (!(*addrs & 1))
continue;
crc = ether_crc_le(6, addrs);
crc >>= 26;
hash_table[crc >> 4] |= 1 << (crc & 0xf);
}
sbus_writel(hash_table[0], bregs + BMAC_HTABLE0);
sbus_writel(hash_table[1], bregs + BMAC_HTABLE1);
sbus_writel(hash_table[2], bregs + BMAC_HTABLE2);
sbus_writel(hash_table[3], bregs + BMAC_HTABLE3);
}
/* Re-enable the receiver. */
tmp = sbus_readl(bregs + BMAC_RXCFG);
tmp |= BIGMAC_RXCFG_ENABLE;
sbus_writel(tmp, bregs + BMAC_RXCFG);
}
/* Ethtool support... */
static void bigmac_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
struct bigmac *bp = dev->priv;
strcpy(info->driver, "sunbmac");
strcpy(info->version, "2.0");
sprintf(info->bus_info, "SBUS:%d",
bp->qec_sdev->slot);
}
static u32 bigmac_get_link(struct net_device *dev)
{
struct bigmac *bp = dev->priv;
spin_lock_irq(&bp->lock);
bp->sw_bmsr = bigmac_tcvr_read(bp, bp->tregs, BIGMAC_BMSR);
spin_unlock_irq(&bp->lock);
return (bp->sw_bmsr & BMSR_LSTATUS);
}
static const struct ethtool_ops bigmac_ethtool_ops = {
.get_drvinfo = bigmac_get_drvinfo,
.get_link = bigmac_get_link,
};
static int __devinit bigmac_ether_init(struct sbus_dev *qec_sdev)
{
struct net_device *dev;
static int version_printed;
struct bigmac *bp;
u8 bsizes, bsizes_more;
int i;
DECLARE_MAC_BUF(mac);
/* Get a new device struct for this interface. */
dev = alloc_etherdev(sizeof(struct bigmac));
if (!dev)
return -ENOMEM;
if (version_printed++ == 0)
printk(KERN_INFO "%s", version);
dev->base_addr = (long) qec_sdev;
for (i = 0; i < 6; i++)
dev->dev_addr[i] = idprom->id_ethaddr[i];
/* Setup softc, with backpointers to QEC and BigMAC SBUS device structs. */
bp = dev->priv;
bp->qec_sdev = qec_sdev;
bp->bigmac_sdev = qec_sdev->child;
SET_NETDEV_DEV(dev, &bp->bigmac_sdev->ofdev.dev);
spin_lock_init(&bp->lock);
/* Verify the registers we expect, are actually there. */
if ((bp->bigmac_sdev->num_registers != 3) ||
(bp->qec_sdev->num_registers != 2)) {
printk(KERN_ERR "BIGMAC: Device does not have 2 and 3 regs, it has %d and %d.\n",
bp->qec_sdev->num_registers,
bp->bigmac_sdev->num_registers);
printk(KERN_ERR "BIGMAC: Would you like that for here or to go?\n");
goto fail_and_cleanup;
}
/* Map in QEC global control registers. */
bp->gregs = sbus_ioremap(&bp->qec_sdev->resource[0], 0,
GLOB_REG_SIZE, "BigMAC QEC GLobal Regs");
if (!bp->gregs) {
printk(KERN_ERR "BIGMAC: Cannot map QEC global registers.\n");
goto fail_and_cleanup;
}
/* Make sure QEC is in BigMAC mode. */
if ((sbus_readl(bp->gregs + GLOB_CTRL) & 0xf0000000) != GLOB_CTRL_BMODE) {
printk(KERN_ERR "BigMAC: AIEEE, QEC is not in BigMAC mode!\n");
goto fail_and_cleanup;
}
/* Reset the QEC. */
if (qec_global_reset(bp->gregs))
goto fail_and_cleanup;
/* Get supported SBUS burst sizes. */
bsizes = prom_getintdefault(bp->qec_sdev->prom_node,
"burst-sizes",
0xff);
bsizes_more = prom_getintdefault(bp->qec_sdev->bus->prom_node,
"burst-sizes",
0xff);
bsizes &= 0xff;
if (bsizes_more != 0xff)
bsizes &= bsizes_more;
if (bsizes == 0xff || (bsizes & DMA_BURST16) == 0 ||
(bsizes & DMA_BURST32) == 0)
bsizes = (DMA_BURST32 - 1);
bp->bigmac_bursts = bsizes;
/* Perform QEC initialization. */
qec_init(bp);
/* Map in the BigMAC channel registers. */
bp->creg = sbus_ioremap(&bp->bigmac_sdev->resource[0], 0,
CREG_REG_SIZE, "BigMAC QEC Channel Regs");
if (!bp->creg) {
printk(KERN_ERR "BIGMAC: Cannot map QEC channel registers.\n");
goto fail_and_cleanup;
}
/* Map in the BigMAC control registers. */
bp->bregs = sbus_ioremap(&bp->bigmac_sdev->resource[1], 0,
BMAC_REG_SIZE, "BigMAC Primary Regs");
if (!bp->bregs) {
printk(KERN_ERR "BIGMAC: Cannot map BigMAC primary registers.\n");
goto fail_and_cleanup;
}
/* Map in the BigMAC transceiver registers, this is how you poke at
* the BigMAC's PHY.
*/
bp->tregs = sbus_ioremap(&bp->bigmac_sdev->resource[2], 0,
TCVR_REG_SIZE, "BigMAC Transceiver Regs");
if (!bp->tregs) {
printk(KERN_ERR "BIGMAC: Cannot map BigMAC transceiver registers.\n");
goto fail_and_cleanup;
}
/* Stop the BigMAC. */
bigmac_stop(bp);
/* Allocate transmit/receive descriptor DVMA block. */
bp->bmac_block = sbus_alloc_consistent(bp->bigmac_sdev,
PAGE_SIZE,
&bp->bblock_dvma);
if (bp->bmac_block == NULL || bp->bblock_dvma == 0) {
printk(KERN_ERR "BIGMAC: Cannot allocate consistent DMA.\n");
goto fail_and_cleanup;
}
/* Get the board revision of this BigMAC. */
bp->board_rev = prom_getintdefault(bp->bigmac_sdev->prom_node,
"board-version", 1);
/* Init auto-negotiation timer state. */
init_timer(&bp->bigmac_timer);
bp->timer_state = asleep;
bp->timer_ticks = 0;
/* Backlink to generic net device struct. */
bp->dev = dev;
/* Set links to our BigMAC open and close routines. */
dev->open = &bigmac_open;
dev->stop = &bigmac_close;
dev->hard_start_xmit = &bigmac_start_xmit;
dev->ethtool_ops = &bigmac_ethtool_ops;
/* Set links to BigMAC statistic and multi-cast loading code. */
dev->get_stats = &bigmac_get_stats;
dev->set_multicast_list = &bigmac_set_multicast;
dev->tx_timeout = &bigmac_tx_timeout;
dev->watchdog_timeo = 5*HZ;
/* Finish net device registration. */
dev->irq = bp->bigmac_sdev->irqs[0];
dev->dma = 0;
if (register_netdev(dev)) {
printk(KERN_ERR "BIGMAC: Cannot register device.\n");
goto fail_and_cleanup;
}
dev_set_drvdata(&bp->bigmac_sdev->ofdev.dev, bp);
printk(KERN_INFO "%s: BigMAC 100baseT Ethernet %s\n",
dev->name, print_mac(mac, dev->dev_addr));
return 0;
fail_and_cleanup:
/* Something went wrong, undo whatever we did so far. */
/* Free register mappings if any. */
if (bp->gregs)
sbus_iounmap(bp->gregs, GLOB_REG_SIZE);
if (bp->creg)
sbus_iounmap(bp->creg, CREG_REG_SIZE);
if (bp->bregs)
sbus_iounmap(bp->bregs, BMAC_REG_SIZE);
if (bp->tregs)
sbus_iounmap(bp->tregs, TCVR_REG_SIZE);
if (bp->bmac_block)
sbus_free_consistent(bp->bigmac_sdev,
PAGE_SIZE,
bp->bmac_block,
bp->bblock_dvma);
/* This also frees the co-located 'dev->priv' */
free_netdev(dev);
return -ENODEV;
}
/* QEC can be the parent of either QuadEthernet or
* a BigMAC. We want the latter.
*/
static int __devinit bigmac_sbus_probe(struct of_device *dev, const struct of_device_id *match)
{
struct sbus_dev *sdev = to_sbus_device(&dev->dev);
struct device_node *dp = dev->node;
if (!strcmp(dp->name, "be"))
sdev = sdev->parent;
return bigmac_ether_init(sdev);
}
static int __devexit bigmac_sbus_remove(struct of_device *dev)
{
struct bigmac *bp = dev_get_drvdata(&dev->dev);
struct net_device *net_dev = bp->dev;
unregister_netdevice(net_dev);
sbus_iounmap(bp->gregs, GLOB_REG_SIZE);
sbus_iounmap(bp->creg, CREG_REG_SIZE);
sbus_iounmap(bp->bregs, BMAC_REG_SIZE);
sbus_iounmap(bp->tregs, TCVR_REG_SIZE);
sbus_free_consistent(bp->bigmac_sdev,
PAGE_SIZE,
bp->bmac_block,
bp->bblock_dvma);
free_netdev(net_dev);
dev_set_drvdata(&dev->dev, NULL);
return 0;
}
static struct of_device_id bigmac_sbus_match[] = {
{
.name = "qec",
},
{
.name = "be",
},
{},
};
MODULE_DEVICE_TABLE(of, bigmac_sbus_match);
static struct of_platform_driver bigmac_sbus_driver = {
.name = "sunbmac",
.match_table = bigmac_sbus_match,
.probe = bigmac_sbus_probe,
.remove = __devexit_p(bigmac_sbus_remove),
};
static int __init bigmac_init(void)
{
return of_register_driver(&bigmac_sbus_driver, &sbus_bus_type);
}
static void __exit bigmac_exit(void)
{
of_unregister_driver(&bigmac_sbus_driver);
}
module_init(bigmac_init);
module_exit(bigmac_exit);