* Patch by Markus Pietrek, 24 Feb 2004:

  NS9750 DevBoard added

* Patch by Pierre AUBERT, 24 Feb 2004
  add USB support for MPC5200

* Patch by Steven Scholz, 24 Feb 2004:
  - fix MII commands to use values from last command

* Patch by Torsten Demke, 24 Feb 2004:
  Add support for the eXalion platform (SPSW-8240, F-30, F-300)

1 files changed, 797 insertions, 0 deletions

diff --git a/drivers/ns9750_eth.c b/drivers/ns9750_eth.c
new file mode 100644
index 00000000000..067ff8efabe
--- /dev/null
+++ b/drivers/ns9750_eth.c
@@ -0,0 +1,797 @@
+/***********************************************************************
+ *
+ * Copyright (C) 2004 by FS Forth-Systeme GmbH.
+ * All rights reserved.
+ *
+ * $Id: ns9750_eth.c,v 1.2 2004/02/24 14:09:39 mpietrek Exp $
+ * @Author: Markus Pietrek
+ * @Descr: Ethernet driver for the NS9750. Uses DMA Engine with polling
+ *	   interrupt status. But interrupts are not enabled.
+ *	   Only one tx buffer descriptor and the RXA buffer descriptor are used
+ *	   Currently no transmit lockup handling is included. eth_send has a 5s
+ *	   timeout for sending frames. No retransmits are performed when an
+ *	   error occurs.
+ * @References: [1] NS9750 Hardware Reference, December 2003
+ *		[2] Intel LXT971 Datasheet #249414 Rev. 02
+ *		[3] NS7520 Linux Ethernet Driver
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ ***********************************************************************/
+
+#include <common.h>
+#include <net.h>		/* NetSendPacket */
+
+#include "ns9750_eth.h"		/* for Ethernet and PHY */
+
+#ifdef CONFIG_DRIVER_NS9750_ETHERNET
+
+/* some definition to make transistion to linux easier */
+
+#define NS9750_DRIVER_NAME	"eth"
+#define KERN_WARNING		"Warning:"
+#define KERN_ERR		"Error:"
+#define KERN_INFO		"Info:"
+
+#if 0
+# define DEBUG
+#endif
+
+#ifdef	DEBUG
+# define printk			printf
+
+# define DEBUG_INIT		0x0001
+# define DEBUG_MINOR		0x0002
+# define DEBUG_RX		0x0004
+# define DEBUG_TX		0x0008
+# define DEBUG_INT		0x0010
+# define DEBUG_POLL		0x0020
+# define DEBUG_LINK		0x0040
+# define DEBUG_MII		0x0100
+# define DEBUG_MII_LOW		0x0200
+# define DEBUG_MEM		0x0400
+# define DEBUG_ERROR		0x4000
+# define DEBUG_ERROR_CRIT	0x8000
+
+static int nDebugLvl = DEBUG_ERROR_CRIT;
+
+# define DEBUG_ARGS0( FLG, a0 ) if( ( nDebugLvl & (FLG) ) == (FLG) ) \
+		printf("%s: " a0, __FUNCTION__, 0, 0, 0, 0, 0, 0 )
+# define DEBUG_ARGS1( FLG, a0, a1 ) if( ( nDebugLvl & (FLG) ) == (FLG)) \
+		printf("%s: " a0, __FUNCTION__, (int)(a1), 0, 0, 0, 0, 0 )
+# define DEBUG_ARGS2( FLG, a0, a1, a2 ) if( (nDebugLvl & (FLG)) ==(FLG))\
+		printf("%s: " a0, __FUNCTION__, (int)(a1), (int)(a2), 0, 0,0,0 )
+# define DEBUG_ARGS3( FLG, a0, a1, a2, a3 ) if((nDebugLvl &(FLG))==(FLG))\
+		printf("%s: "a0,__FUNCTION__,(int)(a1),(int)(a2),(int)(a3),0,0,0)
+# define DEBUG_FN( FLG ) if( (nDebugLvl & (FLG)) == (FLG) ) \
+		printf("\r%s:line %d\n", (int)__FUNCTION__, __LINE__, 0,0,0,0);
+# define ASSERT( expr, func ) if( !( expr ) ) { \
+		printf( "Assertion failed! %s:line %d %s\n", \
+		(int)__FUNCTION__,__LINE__,(int)(#expr),0,0,0); \
+		func }
+#else /* DEBUG */
+# define printk(...)
+# define DEBUG_ARGS0( FLG, a0 )
+# define DEBUG_ARGS1( FLG, a0, a1 )
+# define DEBUG_ARGS2( FLG, a0, a1, a2 )
+# define DEBUG_ARGS3( FLG, a0, a1, a2, a3 )
+# define DEBUG_FN( n )
+# define ASSERT(expr, func)
+#endif /* DEBUG */
+
+#define NS9750_MII_NEG_DELAY		(5*CFG_HZ) /* in s */
+#define TX_TIMEOUT			(5*CFG_HZ) /* in s */
+
+/* @TODO move it to eeprom.h */
+#define FS_EEPROM_AUTONEG_MASK		0x7
+#define FS_EEPROM_AUTONEG_SPEED_MASK	0x1
+#define FS_EEPROM_AUTONEG_SPEED_10	0x0
+#define FS_EEPROM_AUTONEG_SPEED_100	0x1
+#define FS_EEPROM_AUTONEG_DUPLEX_MASK	0x2
+#define FS_EEPROM_AUTONEG_DUPLEX_HALF	0x0
+#define FS_EEPROM_AUTONEG_DUPLEX_FULL	0x2
+#define FS_EEPROM_AUTONEG_ENABLE_MASK	0x4
+#define FS_EEPROM_AUTONEG_DISABLE	0x0
+#define FS_EEPROM_AUTONEG_ENABLE	0x4
+
+/* buffer descriptors taken from [1] p.306 */
+typedef struct
+{
+	unsigned int* punSrc;
+	unsigned int unLen;	/* 11 bits */
+	unsigned int* punDest;	/* unused */
+	union {
+		unsigned int unReg;
+		struct {
+			unsigned uStatus : 16;
+			unsigned uRes : 12;
+			unsigned uFull : 1;
+			unsigned uEnable : 1;
+			unsigned uInt : 1;
+			unsigned uWrap : 1;
+		} bits;
+	} s;
+} rx_buffer_desc_t;
+
+typedef struct
+{
+	unsigned int* punSrc;
+	unsigned int unLen;	/* 10 bits */
+	unsigned int* punDest;	/* unused */
+	union {
+		unsigned int unReg; /* only 32bit accesses may done to NS9750
+				     * eth engine */
+		struct {
+			unsigned uStatus : 16;
+			unsigned uRes : 12;
+			unsigned uFull : 1;
+			unsigned uLast : 1;
+			unsigned uInt : 1;
+			unsigned uWrap : 1;
+		} bits;
+	} s;
+} tx_buffer_desc_t;
+
+static int ns9750_eth_reset( void );
+
+static void ns9750_link_force( void );
+static void ns9750_link_auto_negotiate( void );
+static void ns9750_link_update_egcr( void );
+static void ns9750_link_print_changed( void );
+
+/* the PHY stuff */
+
+static char ns9750_mii_identify_phy( void );
+static unsigned short ns9750_mii_read( unsigned short uiRegister );
+static void ns9750_mii_write( unsigned short uiRegister, unsigned short uiData );
+static unsigned int ns9750_mii_get_clock_divisor( unsigned int unMaxMDIOClk );
+static unsigned int ns9750_mii_poll_busy( void );
+
+static unsigned int nPhyMaxMdioClock = PHY_MDIO_MAX_CLK;
+static unsigned char ucLinkMode =      FS_EEPROM_AUTONEG_ENABLE;
+static unsigned int uiLastLinkStatus;
+static PhyType phyDetected = PHY_NONE;
+
+/* we use only one tx buffer descriptor */
+static tx_buffer_desc_t* pTxBufferDesc =
+	(tx_buffer_desc_t*) get_eth_reg_addr( NS9750_ETH_TXBD );
+
+/* we use only one rx buffer descriptor of the 4 */
+static rx_buffer_desc_t aRxBufferDesc[ 4 ];
+
+/***********************************************************************
+ * @Function: eth_init
+ * @Return: -1 on failure otherwise 0
+ * @Descr: Initializes the ethernet engine and uses either FS Forth's default
+ *	   MAC addr or the one in environment
+ ***********************************************************************/
+
+int eth_init (bd_t * pbis)
+{
+	/* This default MAC Addr is reserved by FS Forth-Systeme for the case of
+	   EEPROM failures */
+	unsigned char aucMACAddr[6] = { 0x00, 0x04, 0xf3, 0x00, 0x06, 0x35 };
+	char *pcTmp = getenv ("ethaddr");
+	char *pcEnd;
+	int i;
+
+	DEBUG_FN (DEBUG_INIT);
+
+	/* no need to check for hardware */
+
+	if (!ns9750_eth_reset ())
+		return -1;
+
+	if (pcTmp != NULL)
+		for (i = 0; i < 6; i++) {
+			aucMACAddr[i] =
+				pcTmp ? simple_strtoul (pcTmp, &pcEnd,
+							16) : 0;
+			pcTmp = (*pcTmp) ? pcEnd + 1 : pcEnd;
+		}
+
+	/* configure ethernet address */
+
+	*get_eth_reg_addr (NS9750_ETH_SA1) =
+		aucMACAddr[5] << 8 | aucMACAddr[4];
+	*get_eth_reg_addr (NS9750_ETH_SA2) =
+		aucMACAddr[3] << 8 | aucMACAddr[2];
+	*get_eth_reg_addr (NS9750_ETH_SA3) =
+		aucMACAddr[1] << 8 | aucMACAddr[0];
+
+	/* enable hardware */
+
+	*get_eth_reg_addr (NS9750_ETH_MAC1) = NS9750_ETH_MAC1_RXEN;
+
+	/* the linux kernel may give packets < 60 bytes, for example arp */
+	*get_eth_reg_addr (NS9750_ETH_MAC2) = NS9750_ETH_MAC2_CRCEN |
+		NS9750_ETH_MAC2_PADEN | NS9750_ETH_MAC2_HUGE;
+
+	/* enable receive and transmit FIFO, use 10/100 Mbps MII */
+	*get_eth_reg_addr (NS9750_ETH_EGCR1) =
+		NS9750_ETH_EGCR1_ETXWM |
+		NS9750_ETH_EGCR1_ERX |
+		NS9750_ETH_EGCR1_ERXDMA |
+		NS9750_ETH_EGCR1_ETX |
+		NS9750_ETH_EGCR1_ETXDMA | NS9750_ETH_EGCR1_ITXA;
+
+	/* prepare DMA descriptors */
+	for (i = 0; i < 4; i++) {
+		aRxBufferDesc[i].punSrc = 0;
+		aRxBufferDesc[i].unLen = 0;
+		aRxBufferDesc[i].s.bits.uWrap = 1;
+		aRxBufferDesc[i].s.bits.uInt = 1;
+		aRxBufferDesc[i].s.bits.uEnable = 0;
+		aRxBufferDesc[i].s.bits.uFull = 0;
+	}
+
+	/* NetRxPackets[ 0 ] is initialized before eth_init is called and never
+	   changes. NetRxPackets is 32bit aligned */
+	aRxBufferDesc[0].punSrc = (unsigned int *) NetRxPackets[0];
+	aRxBufferDesc[0].s.bits.uEnable = 1;
+	aRxBufferDesc[0].unLen = 1522;	/* as stated in [1] p.307 */
+
+	*get_eth_reg_addr (NS9750_ETH_RXAPTR) =
+		(unsigned int) &aRxBufferDesc[0];
+
+	/* [1] Tab. 221 states less than 5us */
+	*get_eth_reg_addr (NS9750_ETH_EGCR1) |= NS9750_ETH_EGCR1_ERXINIT;
+	while (!
+	       (*get_eth_reg_addr (NS9750_ETH_EGSR) & NS9750_ETH_EGSR_RXINIT))
+		/* wait for finish */
+		udelay (1);
+
+	/* @TODO do we need to clear RXINIT? */
+	*get_eth_reg_addr (NS9750_ETH_EGCR1) &= ~NS9750_ETH_EGCR1_ERXINIT;
+
+	*get_eth_reg_addr (NS9750_ETH_RXFREE) = 0x1;
+
+	return 0;
+}
+
+/***********************************************************************
+ * @Function: eth_send
+ * @Return: -1 on timeout otherwise 1
+ * @Descr: sends one frame by DMA
+ ***********************************************************************/
+
+int eth_send (volatile void *pPacket, int nLen)
+{
+	ulong ulTimeout;
+
+	DEBUG_FN (DEBUG_TX);
+
+	/* clear old status values */
+	*get_eth_reg_addr (NS9750_ETH_EINTR) &=
+		*get_eth_reg_addr (NS9750_ETH_EINTR) & NS9750_ETH_EINTR_TX_MA;
+
+	/* prepare Tx Descriptors */
+
+	pTxBufferDesc->punSrc = (unsigned int *) pPacket;	/* pPacket is 32bit
+								 * aligned */
+	pTxBufferDesc->unLen = nLen;
+	/* only 32bit accesses allowed. wrap, full, interrupt and enabled to 1 */
+	pTxBufferDesc->s.unReg = 0xf0000000;
+	/* pTxBufferDesc is the first possible buffer descriptor */
+	*get_eth_reg_addr (NS9750_ETH_TXPTR) = 0x0;
+
+	/* enable processor for next frame */
+
+	*get_eth_reg_addr (NS9750_ETH_EGCR2) &= ~NS9750_ETH_EGCR2_TCLER;
+	*get_eth_reg_addr (NS9750_ETH_EGCR2) |= NS9750_ETH_EGCR2_TCLER;
+
+	ulTimeout = get_timer (0);
+
+	DEBUG_ARGS0 (DEBUG_TX | DEBUG_MINOR,
+		     "Waiting for transmission to finish\n");
+	while (!
+	       (*get_eth_reg_addr (NS9750_ETH_EINTR) &
+		(NS9750_ETH_EINTR_TXDONE | NS9750_ETH_EINTR_TXERR))) {
+		/* do nothing, wait for completion */
+		if (get_timer (0) - ulTimeout > TX_TIMEOUT) {
+			DEBUG_ARGS0 (DEBUG_TX, "Transmit Timed out\n");
+			return -1;
+		}
+	}
+	DEBUG_ARGS0 (DEBUG_TX | DEBUG_MINOR, "transmitted...\n");
+
+	return 0;
+}
+
+/***********************************************************************
+ * @Function: eth_rx
+ * @Return: size of last frame in bytes or 0 if no frame available
+ * @Descr: gives one frame to U-Boot which has been copied by DMA engine already
+ *	   to NetRxPackets[ 0 ].
+ ***********************************************************************/
+
+int eth_rx (void)
+{
+	int nLen = 0;
+	unsigned int unStatus;
+
+	unStatus =
+		*get_eth_reg_addr (NS9750_ETH_EINTR) & NS9750_ETH_EINTR_RX_MA;
+
+	if (!unStatus)
+		/* no packet available, return immediately */
+		return 0;
+
+	DEBUG_FN (DEBUG_RX);
+
+	/* unLen always < max(nLen) and discard checksum */
+	nLen = (int) aRxBufferDesc[0].unLen - 4;
+
+	/* acknowledge status register */
+	*get_eth_reg_addr (NS9750_ETH_EINTR) = unStatus;
+
+	aRxBufferDesc[0].unLen = 1522;
+	aRxBufferDesc[0].s.bits.uFull = 0;
+
+	/* Buffer A descriptor available again */
+	*get_eth_reg_addr (NS9750_ETH_RXFREE) |= 0x1;
+
+	/* NetReceive may call eth_send. Due to a possible bug of the NS9750 we
+	 * have to acknowledge the received frame before sending a new one */
+	if (unStatus & NS9750_ETH_EINTR_RXDONEA)
+		NetReceive (NetRxPackets[0], nLen);
+
+	return nLen;
+}
+
+/***********************************************************************
+ * @Function: eth_halt
+ * @Return: n/a
+ * @Descr: stops the ethernet engine
+ ***********************************************************************/
+
+void eth_halt (void)
+{
+	DEBUG_FN (DEBUG_INIT);
+
+	*get_eth_reg_addr (NS9750_ETH_MAC1) &= ~NS9750_ETH_MAC1_RXEN;
+	*get_eth_reg_addr (NS9750_ETH_EGCR1) &= ~(NS9750_ETH_EGCR1_ERX |
+						  NS9750_ETH_EGCR1_ERXDMA |
+						  NS9750_ETH_EGCR1_ETX |
+						  NS9750_ETH_EGCR1_ETXDMA);
+}
+
+/***********************************************************************
+ * @Function: ns9750_eth_reset
+ * @Return: 0 on failure otherwise 1
+ * @Descr: resets the ethernet interface and the PHY,
+ *	   performs auto negotiation or fixed modes
+ ***********************************************************************/
+
+static int ns9750_eth_reset (void)
+{
+	DEBUG_FN (DEBUG_MINOR);
+
+	/* Reset MAC */
+	*get_eth_reg_addr (NS9750_ETH_EGCR1) |= NS9750_ETH_EGCR1_MAC_HRST;
+	udelay (5);		/* according to [1], p.322 */
+	*get_eth_reg_addr (NS9750_ETH_EGCR1) &= ~NS9750_ETH_EGCR1_MAC_HRST;
+
+	/* reset and initialize PHY */
+
+	*get_eth_reg_addr (NS9750_ETH_MAC1) &= ~NS9750_ETH_MAC1_SRST;
+
+	/* we don't support hot plugging of PHY, therefore we don't reset
+	   phyDetected and nPhyMaxMdioClock here. The risk is if the setting is
+	   incorrect the first open
+	   may detect the PHY correctly but succeding will fail
+	   For reseting the PHY and identifying we have to use the standard
+	   MDIO CLOCK value 2.5 MHz only after hardware reset
+	   After having identified the PHY we will do faster */
+
+	*get_eth_reg_addr (NS9750_ETH_MCFG) =
+		ns9750_mii_get_clock_divisor (nPhyMaxMdioClock);
+
+	/* reset PHY */
+	ns9750_mii_write (PHY_COMMON_CTRL, PHY_COMMON_CTRL_RESET);
+	ns9750_mii_write (PHY_COMMON_CTRL, 0);
+
+	/* @TODO check time */
+	udelay (3000);		/* [2] p.70 says at least 300us reset recovery time. But
+				   go sure, it didn't worked stable at higher timer
+				   frequencies under LxNETES-2.x */
+
+	/* MII clock has been setup to default, ns9750_mii_identify_phy should
+	   work for all */
+
+	if (!ns9750_mii_identify_phy ()) {
+		printk (KERN_ERR NS9750_DRIVER_NAME
+			": Unsupported PHY, aborting\n");
+		return 0;
+	}
+
+	/* now take the highest MDIO clock possible after detection */
+	*get_eth_reg_addr (NS9750_ETH_MCFG) =
+		ns9750_mii_get_clock_divisor (nPhyMaxMdioClock);
+
+
+	/* PHY has been detected, so there can be no abort reason and we can
+	   finish initializing ethernet */
+
+	uiLastLinkStatus = 0xff;	/* undefined */
+
+	if ((ucLinkMode & FS_EEPROM_AUTONEG_ENABLE_MASK) ==
+	    FS_EEPROM_AUTONEG_DISABLE)
+		/* use parameters defined */
+		ns9750_link_force ();
+	else
+		ns9750_link_auto_negotiate ();
+
+	if (phyDetected == PHY_LXT971A)
+		/* set LED2 to link mode */
+		ns9750_mii_write (PHY_LXT971_LED_CFG,
+				  PHY_LXT971_LED_CFG_LINK_ACT <<
+				  PHY_LXT971_LED_CFG_SHIFT_LED2);
+
+	return 1;
+}
+
+/***********************************************************************
+ * @Function: ns9750_link_force
+ * @Return: void
+ * @Descr: configures eth and MII to use the link mode defined in
+ *	   ucLinkMode
+ ***********************************************************************/
+
+static void ns9750_link_force (void)
+{
+	unsigned short uiControl;
+
+	DEBUG_FN (DEBUG_LINK);
+
+	uiControl = ns9750_mii_read (PHY_COMMON_CTRL);
+	uiControl &= ~(PHY_COMMON_CTRL_SPD_MA |
+		       PHY_COMMON_CTRL_AUTO_NEG | PHY_COMMON_CTRL_DUPLEX);
+
+	uiLastLinkStatus = 0;
+
+	if ((ucLinkMode & FS_EEPROM_AUTONEG_SPEED_MASK) ==
+	    FS_EEPROM_AUTONEG_SPEED_100) {
+		uiControl |= PHY_COMMON_CTRL_SPD_100;
+		uiLastLinkStatus |= PHY_LXT971_STAT2_100BTX;
+	} else
+		uiControl |= PHY_COMMON_CTRL_SPD_10;
+
+	if ((ucLinkMode & FS_EEPROM_AUTONEG_DUPLEX_MASK) ==
+	    FS_EEPROM_AUTONEG_DUPLEX_FULL) {
+		uiControl |= PHY_COMMON_CTRL_DUPLEX;
+		uiLastLinkStatus |= PHY_LXT971_STAT2_DUPLEX_MODE;
+	}
+
+	ns9750_mii_write (PHY_COMMON_CTRL, uiControl);
+
+	ns9750_link_print_changed ();
+	ns9750_link_update_egcr ();
+}
+
+/***********************************************************************
+ * @Function: ns9750_link_auto_negotiate
+ * @Return: void
+ * @Descr: performs auto-negotation of link.
+ ***********************************************************************/
+
+static void ns9750_link_auto_negotiate (void)
+{
+	unsigned long ulStartJiffies;
+	unsigned short uiStatus;
+
+	DEBUG_FN (DEBUG_LINK);
+
+	/* run auto-negotation */
+	/* define what we are capable of */
+	ns9750_mii_write (PHY_COMMON_AUTO_ADV,
+			  PHY_COMMON_AUTO_ADV_100BTXFD |
+			  PHY_COMMON_AUTO_ADV_100BTX |
+			  PHY_COMMON_AUTO_ADV_10BTFD |
+			  PHY_COMMON_AUTO_ADV_10BT |
+			  PHY_COMMON_AUTO_ADV_802_3);
+	/* start auto-negotiation */
+	ns9750_mii_write (PHY_COMMON_CTRL,
+			  PHY_COMMON_CTRL_AUTO_NEG |
+			  PHY_COMMON_CTRL_RES_AUTO);
+
+	/* wait for completion */
+
+	ulStartJiffies = get_ticks ();
+	while (get_ticks () < ulStartJiffies + NS9750_MII_NEG_DELAY) {
+		uiStatus = ns9750_mii_read (PHY_COMMON_STAT);
+		if ((uiStatus &
+		     (PHY_COMMON_STAT_AN_COMP | PHY_COMMON_STAT_LNK_STAT)) ==
+		    (PHY_COMMON_STAT_AN_COMP | PHY_COMMON_STAT_LNK_STAT)) {
+			/* lucky we are, auto-negotiation succeeded */
+			ns9750_link_print_changed ();
+			ns9750_link_update_egcr ();
+			return;
+		}
+	}
+
+	DEBUG_ARGS0 (DEBUG_LINK, "auto-negotiation timed out\n");
+	/* ignore invalid link settings */
+}
+
+/***********************************************************************
+ * @Function: ns9750_link_update_egcr
+ * @Return: void
+ * @Descr: updates the EGCR and MAC2 link status after mode change or
+ *	   auto-negotation
+ ***********************************************************************/
+
+static void ns9750_link_update_egcr (void)
+{
+	unsigned int unEGCR;
+	unsigned int unMAC2;
+	unsigned int unIPGT;
+
+	DEBUG_FN (DEBUG_LINK);
+
+	unEGCR = *get_eth_reg_addr (NS9750_ETH_EGCR1);
+	unMAC2 = *get_eth_reg_addr (NS9750_ETH_MAC2);
+	unIPGT = *get_eth_reg_addr (NS9750_ETH_IPGT) & ~NS9750_ETH_IPGT_MA;
+
+	unMAC2 &= ~NS9750_ETH_MAC2_FULLD;
+	if ((uiLastLinkStatus & PHY_LXT971_STAT2_DUPLEX_MODE)
+	    == PHY_LXT971_STAT2_DUPLEX_MODE) {
+		unMAC2 |= NS9750_ETH_MAC2_FULLD;
+		unIPGT |= 0x15; /* see [1] p. 339 */
+	} else
+		unIPGT |= 0x12; /* see [1] p. 339 */
+
+	*get_eth_reg_addr (NS9750_ETH_MAC2) = unMAC2;
+	*get_eth_reg_addr (NS9750_ETH_EGCR1) = unEGCR;
+	*get_eth_reg_addr (NS9750_ETH_IPGT) = unIPGT;
+}
+
+/***********************************************************************
+ * @Function: ns9750_link_print_changed
+ * @Return: void
+ * @Descr: checks whether the link status has changed and if so prints
+ *	   the new mode
+ ***********************************************************************/
+
+static void ns9750_link_print_changed (void)
+{
+	unsigned short uiStatus;
+	unsigned short uiControl;
+
+	DEBUG_FN (DEBUG_LINK);
+
+	uiControl = ns9750_mii_read (PHY_COMMON_CTRL);
+
+	if ((uiControl & PHY_COMMON_CTRL_AUTO_NEG) ==
+	    PHY_COMMON_CTRL_AUTO_NEG) {
+		/* PHY_COMMON_STAT_LNK_STAT is only set on autonegotiation */
+		uiStatus = ns9750_mii_read (PHY_COMMON_STAT);
+
+		if (!(uiStatus & PHY_COMMON_STAT_LNK_STAT)) {
+			printk (KERN_WARNING NS9750_DRIVER_NAME
+				": link down\n");
+			/* @TODO Linux: carrier_off */
+		} else {
+			/* @TODO Linux: carrier_on */
+			if (phyDetected == PHY_LXT971A) {
+				uiStatus = ns9750_mii_read (PHY_LXT971_STAT2);
+				uiStatus &= (PHY_LXT971_STAT2_100BTX |
+					     PHY_LXT971_STAT2_DUPLEX_MODE |
+					     PHY_LXT971_STAT2_AUTO_NEG);
+
+				/* mask out all uninteresting parts */
+			}
+			/* other PHYs must store there link information in
+			   uiStatus as PHY_LXT971 */
+		}
+	} else {
+		/* mode has been forced, so uiStatus should be the same as the
+		   last link status, enforce printing */
+		uiStatus = uiLastLinkStatus;
+		uiLastLinkStatus = 0xff;
+	}
+
+	if (uiStatus != uiLastLinkStatus) {
+		/* save current link status */
+		uiLastLinkStatus = uiStatus;
+
+		/* print new link status */
+
+		printk (KERN_INFO NS9750_DRIVER_NAME
+			": link mode %i Mbps %s duplex %s\n",
+			(uiStatus & PHY_LXT971_STAT2_100BTX) ? 100 : 10,
+			(uiStatus & PHY_LXT971_STAT2_DUPLEX_MODE) ? "full" :
+			"half",
+			(uiStatus & PHY_LXT971_STAT2_AUTO_NEG) ? "(auto)" :
+			"");
+	}
+}
+
+/***********************************************************************
+ * the MII low level stuff
+ ***********************************************************************/
+
+/***********************************************************************
+ * @Function: ns9750_mii_identify_phy
+ * @Return: 1 if supported PHY has been detected otherwise 0
+ * @Descr: checks for supported PHY and prints the IDs.
+ ***********************************************************************/
+
+static char ns9750_mii_identify_phy (void)
+{
+	unsigned short uiID1;
+	unsigned short uiID2;
+	unsigned char *szName;
+	char cRes = 0;
+
+	DEBUG_FN (DEBUG_MII);
+
+	phyDetected = (PhyType) uiID1 = ns9750_mii_read (PHY_COMMON_ID1);
+
+	switch (phyDetected) {
+	case PHY_LXT971A:
+		szName = "LXT971A";
+		uiID2 = ns9750_mii_read (PHY_COMMON_ID2);
+		nPhyMaxMdioClock = PHY_LXT971_MDIO_MAX_CLK;
+		cRes = 1;
+		break;
+	case PHY_NONE:
+	default:
+		/* in case uiID1 == 0 && uiID2 == 0 we may have the wrong
+		   address or reset sets the wrong NS9750_ETH_MCFG_CLKS */
+
+		uiID2 = 0;
+		szName = "unknown";
+		nPhyMaxMdioClock = PHY_MDIO_MAX_CLK;
+		phyDetected = PHY_NONE;
+	}
+
+	printk (KERN_INFO NS9750_DRIVER_NAME
+		": PHY (0x%x, 0x%x) = %s detected\n", uiID1, uiID2, szName);
+
+	return cRes;
+}
+
+/***********************************************************************
+ * @Function: ns9750_mii_read
+ * @Return: the data read from PHY register uiRegister
+ * @Descr: the data read may be invalid if timed out. If so, a message
+ *	   is printed but the invalid data is returned.
+ *	   The fixed device address is being used.
+ ***********************************************************************/
+
+static unsigned short ns9750_mii_read (unsigned short uiRegister)
+{
+	DEBUG_FN (DEBUG_MII_LOW);
+
+	/* write MII register to be read */
+	*get_eth_reg_addr (NS9750_ETH_MADR) =
+		NS9750_ETH_PHY_ADDRESS << 8 | uiRegister;
+
+	*get_eth_reg_addr (NS9750_ETH_MCMD) = NS9750_ETH_MCMD_READ;
+
+	if (!ns9750_mii_poll_busy ())
+		printk (KERN_WARNING NS9750_DRIVER_NAME
+			": MII still busy in read\n");
+	/* continue to read */
+
+	*get_eth_reg_addr (NS9750_ETH_MCMD) = 0;
+
+	return (unsigned short) (*get_eth_reg_addr (NS9750_ETH_MRDD));
+}
+
+
+/***********************************************************************
+ * @Function: ns9750_mii_write
+ * @Return: nothing
+ * @Descr: writes the data to the PHY register. In case of a timeout,
+ *	   no special handling is performed but a message printed
+ *	   The fixed device address is being used.
+ ***********************************************************************/
+
+static void ns9750_mii_write (unsigned short uiRegister,
+			      unsigned short uiData)
+{
+	DEBUG_FN (DEBUG_MII_LOW);
+
+	/* write MII register to be written */
+	*get_eth_reg_addr (NS9750_ETH_MADR) =
+		NS9750_ETH_PHY_ADDRESS << 8 | uiRegister;
+
+	*get_eth_reg_addr (NS9750_ETH_MWTD) = uiData;
+
+	if (!ns9750_mii_poll_busy ()) {
+		printf (KERN_WARNING NS9750_DRIVER_NAME
+			": MII still busy in write\n");
+	}
+}
+
+
+/***********************************************************************
+ * @Function: ns9750_mii_get_clock_divisor
+ * @Return: the clock divisor that should be used in NS9750_ETH_MCFG_CLKS
+ * @Descr: if no clock divisor can be calculated for the
+ *	   current SYSCLK and the maximum MDIO Clock, a warning is printed
+ *	   and the greatest divisor is taken
+ ***********************************************************************/
+
+static unsigned int ns9750_mii_get_clock_divisor (unsigned int unMaxMDIOClk)
+{
+	struct {
+		unsigned int unSysClkDivisor;
+		unsigned int unClks;	/* field for NS9750_ETH_MCFG_CLKS */
+	} PHYClockDivisors[] = {
+		{
+		4, NS9750_ETH_MCFG_CLKS_4}, {
+		6, NS9750_ETH_MCFG_CLKS_6}, {
+		8, NS9750_ETH_MCFG_CLKS_8}, {
+		10, NS9750_ETH_MCFG_CLKS_10}, {
+		20, NS9750_ETH_MCFG_CLKS_20}, {
+		30, NS9750_ETH_MCFG_CLKS_30}, {
+		40, NS9750_ETH_MCFG_CLKS_40}
+	};
+
+	int nIndexSysClkDiv;
+	int nArraySize =
+		sizeof (PHYClockDivisors) / sizeof (PHYClockDivisors[0]);
+	unsigned int unClks = NS9750_ETH_MCFG_CLKS_40;	/* defaults to
+							   greatest div */
+
+	DEBUG_FN (DEBUG_INIT);
+
+	for (nIndexSysClkDiv = 0; nIndexSysClkDiv < nArraySize;
+	     nIndexSysClkDiv++) {
+		/* find first sysclock divisor that isn't higher than 2.5 MHz
+		   clock */
+		if (AHB_CLK_FREQ /
+		    PHYClockDivisors[nIndexSysClkDiv].unSysClkDivisor <=
+		    unMaxMDIOClk) {
+			unClks = PHYClockDivisors[nIndexSysClkDiv].unClks;
+			break;
+		}
+	}
+
+	DEBUG_ARGS2 (DEBUG_INIT,
+		     "Taking MDIO Clock bit mask 0x%0x for max clock %i\n",
+		     unClks, unMaxMDIOClk);
+
+	/* return greatest divisor */
+	return unClks;
+}
+
+/***********************************************************************
+ * @Function: ns9750_mii_poll_busy
+ * @Return: 0 if timed out otherwise the remaing timeout
+ * @Descr: waits until the MII has completed a command or it times out
+ *	   code may be interrupted by hard interrupts.
+ *	   It is not checked what happens on multiple actions when
+ *	   the first is still being busy and we timeout.
+ ***********************************************************************/
+
+static unsigned int ns9750_mii_poll_busy (void)
+{
+	unsigned int unTimeout = 10000;
+
+	DEBUG_FN (DEBUG_MII_LOW);
+
+	while (((*get_eth_reg_addr (NS9750_ETH_MIND) & NS9750_ETH_MIND_BUSY)
+		== NS9750_ETH_MIND_BUSY) && unTimeout)
+		unTimeout--;
+
+	return unTimeout;
+}
+
+#endif /* CONFIG_DRIVER_NS9750_ETHERNET */