/* 
 * 7990.h -- LANCE ethernet IC generic routines.
 * This is an attempt to separate out the bits of various ethernet
 * drivers that are common because they all use the AMD 7990 LANCE
 * (Local Area Network Controller for Ethernet) chip.
 * 
 * Copyright (C) 05/1998 Peter Maydell <pmaydell@chiark.greenend.org.uk>
 *
 * Most of this stuff was obtained by looking at other LANCE drivers,
 * in particular a2065.[ch]. The AMD C-LANCE datasheet was also helpful.
 */

#ifndef _7990_H
#define _7990_H

/* The lance only has two register locations. We communicate mostly via memory. */
struct lance_regs 
{
        unsigned short rdp;                       /* Register Data Port */
        unsigned short rap;                       /* Register Address Port */
};

/* Transmit/receive ring definitions.
 * We allow the specific drivers to override these defaults if they want to.
 * NB: according to lance.c, increasing the number of buffers is a waste
 * of space and reduces the chance that an upper layer will be able to
 * reorder queued Tx packets based on priority. [Clearly there is a minimum
 * limit too: too small and we drop rx packets and can't tx at full speed.]
 * 4+4 seems to be the usual setting; the atarilance driver uses 3 and 5.
 */

/* Blast! This won't work. The problem is that we can't specify a default
 * setting because that would cause the lance_init_block struct to be
 * too long (and overflow the RAM on shared-memory cards like the HP LANCE.
 */
#ifndef LANCE_LOG_TX_BUFFERS
#define LANCE_LOG_TX_BUFFERS 1
#define LANCE_LOG_RX_BUFFERS 3
#endif

#define TX_RING_SIZE (1<<LANCE_LOG_TX_BUFFERS)
#define RX_RING_SIZE (1<<LANCE_LOG_RX_BUFFERS)
#define TX_RING_MOD_MASK (TX_RING_SIZE - 1)
#define RX_RING_MOD_MASK (RX_RING_SIZE - 1)
#define TX_RING_LEN_BITS ((LANCE_LOG_TX_BUFFERS) << 29)
#define RX_RING_LEN_BITS ((LANCE_LOG_RX_BUFFERS) << 29)
#define PKT_BUFF_SIZE (1544)
#define RX_BUFF_SIZE PKT_BUFF_SIZE
#define TX_BUFF_SIZE PKT_BUFF_SIZE

/* Each receive buffer is described by a receive message descriptor (RMD) */
struct lance_rx_desc {
	volatile unsigned short rmd0;        /* low address of packet */
	volatile unsigned char  rmd1_bits;   /* descriptor bits */
	volatile unsigned char  rmd1_hadr;   /* high address of packet */
	volatile short    length;    	    /* This length is 2s complement (negative)!
				     * Buffer length
				     */
	volatile unsigned short mblength;    /* Actual number of bytes received */
};
 
/* Ditto for TMD: */
struct lance_tx_desc {
	volatile unsigned short tmd0;        /* low address of packet */
	volatile unsigned char  tmd1_bits;   /* descriptor bits */
	volatile unsigned char  tmd1_hadr;   /* high address of packet */
	volatile short    length;       	    /* Length is 2s complement (negative)! */
	volatile unsigned short misc;
};

/* There are three memory structures accessed by the LANCE:
 * the initialization block, the receive and transmit descriptor rings,
 * and the data buffers themselves. In fact we might as well put the
 * init block,the Tx and Rx rings and the buffers together in memory:
 */
struct lance_init_block {
        volatile unsigned short mode;            /* Pre-set mode (reg. 15) */
        volatile unsigned char phys_addr[6];     /* Physical ethernet address */
        volatile unsigned filter[2];             /* Multicast filter (64 bits) */

        /* Receive and transmit ring base, along with extra bits. */
        volatile unsigned short rx_ptr;          /* receive descriptor addr */
        volatile unsigned short rx_len;          /* receive len and high addr */
        volatile unsigned short tx_ptr;          /* transmit descriptor addr */
        volatile unsigned short tx_len;          /* transmit len and high addr */
    
        /* The Tx and Rx ring entries must be aligned on 8-byte boundaries. 
         * This will be true if this whole struct is 8-byte aligned.
         */
        volatile struct lance_tx_desc btx_ring[TX_RING_SIZE];
        volatile struct lance_rx_desc brx_ring[RX_RING_SIZE];

        volatile char   tx_buf [TX_RING_SIZE][TX_BUFF_SIZE];
        volatile char   rx_buf [RX_RING_SIZE][RX_BUFF_SIZE];
        /* we use this just to make the struct big enough that we can move its startaddr
         * in order to force alignment to an eight byte boundary.
         */
};

/* This is where we keep all the stuff the driver needs to know about.
 * I'm definitely unhappy about the mechanism for allowing specific
 * drivers to add things...
 */
struct lance_private
{
        char *name;
        volatile struct lance_regs *ll;
        volatile struct lance_init_block *init_block; /* CPU address of RAM */
        volatile struct lance_init_block *lance_init_block; /* LANCE address of RAM */
        
        int rx_new, tx_new;
        int rx_old, tx_old;
        
        int lance_log_rx_bufs, lance_log_tx_bufs;
        int rx_ring_mod_mask, tx_ring_mod_mask;
        
        struct net_device_stats stats;
        int tpe;                                  /* TPE is selected */
        int auto_select;                          /* cable-selection is by carrier */
        unsigned short busmaster_regval;

        unsigned int irq;                         /* IRQ to register */
        
        /* This is because the HP LANCE is disgusting and you have to check 
         * a DIO-specific register every time you read/write the LANCE regs :-<
         * [could we get away with making these some sort of macro?]
         */
        void (*writerap)(void *, unsigned short);
        void (*writerdp)(void *, unsigned short);
        unsigned short (*readrdp)(struct lance_private *);
};

#define CRC_POLYNOMIAL_BE 0x04c11db7UL  /* Ethernet CRC, big endian */
#define CRC_POLYNOMIAL_LE 0xedb88320UL  /* Ethernet CRC, little endian */

/*
 *              Am7990 Control and Status Registers
 */
#define LE_CSR0         0x0000          /* LANCE Controller Status */
#define LE_CSR1         0x0001          /* IADR[15:0] (bit0==0 ie word aligned) */
#define LE_CSR2         0x0002          /* IADR[23:16] (high bits reserved) */
#define LE_CSR3         0x0003          /* Misc */

/*
 *		Bit definitions for CSR0 (LANCE Controller Status)
 */
#define LE_C0_ERR	0x8000		/* Error = BABL | CERR | MISS | MERR */
#define LE_C0_BABL	0x4000		/* Babble: Transmitted too many bits */
#define LE_C0_CERR	0x2000		/* No Heartbeat (10BASE-T) */
#define LE_C0_MISS	0x1000		/* Missed Frame (no rx buffer to put it in) */
#define LE_C0_MERR	0x0800		/* Memory Error */
#define LE_C0_RINT	0x0400		/* Receive Interrupt */
#define LE_C0_TINT	0x0200		/* Transmit Interrupt */
#define LE_C0_IDON	0x0100		/* Initialization Done */
#define LE_C0_INTR	0x0080		/* Interrupt Flag 
                                         = BABL | MISS | MERR | RINT | TINT | IDON */
#define LE_C0_INEA	0x0040		/* Interrupt Enable */
#define LE_C0_RXON	0x0020		/* Receive On */
#define LE_C0_TXON	0x0010		/* Transmit On */
#define LE_C0_TDMD	0x0008		/* Transmit Demand */
#define LE_C0_STOP	0x0004		/* Stop */
#define LE_C0_STRT	0x0002		/* Start */
#define LE_C0_INIT	0x0001		/* Initialize */


/*
 *		Bit definitions for CSR3
 */
#define LE_C3_BSWP	0x0004		/* Byte Swap
					   (on for big endian byte order) */
#define LE_C3_ACON	0x0002		/* ALE Control
					   (on for active low ALE) */
#define LE_C3_BCON	0x0001		/* Byte Control */


/*
 *		Mode Flags
 */
#define LE_MO_PROM	0x8000		/* Promiscuous Mode */
/* these next ones 0x4000 -- 0x0080 are not available on the LANCE 7990,
 * but they are in NetBSD's am7990.h, presumably for backwards-compatible chips
 */
#define LE_MO_DRCVBC  0x4000          /* disable receive broadcast */
#define LE_MO_DRCVPA  0x2000          /* disable physical address detection */
#define LE_MO_DLNKTST 0x1000          /* disable link status */
#define LE_MO_DAPC    0x0800          /* disable automatic polarity correction */
#define LE_MO_MENDECL 0x0400          /* MENDEC loopback mode */
#define LE_MO_LRTTSEL 0x0200          /* lower RX threshold / TX mode selection */
#define LE_MO_PSEL1   0x0100          /* port selection bit1 */
#define LE_MO_PSEL0   0x0080          /* port selection bit0 */
/* and this one is from the C-LANCE data sheet... */
#define LE_MO_EMBA      0x0080          /* Enable Modified Backoff Algorithm 
                                           (C-LANCE, not original LANCE) */
#define LE_MO_INTL	0x0040		/* Internal Loopback */
#define LE_MO_DRTY	0x0020		/* Disable Retry */
#define LE_MO_FCOLL	0x0010		/* Force Collision */
#define LE_MO_DXMTFCS	0x0008		/* Disable Transmit CRC */
#define LE_MO_LOOP	0x0004		/* Loopback Enable */
#define LE_MO_DTX	0x0002		/* Disable Transmitter */
#define LE_MO_DRX	0x0001		/* Disable Receiver */


/*
 *		Receive Flags
 */
#define LE_R1_OWN	0x80		/* LANCE owns the descriptor */
#define LE_R1_ERR	0x40		/* Error */
#define LE_R1_FRA	0x20		/* Framing Error */
#define LE_R1_OFL	0x10		/* Overflow Error */
#define LE_R1_CRC	0x08		/* CRC Error */
#define LE_R1_BUF	0x04		/* Buffer Error */
#define LE_R1_SOP	0x02		/* Start of Packet */
#define LE_R1_EOP	0x01		/* End of Packet */
#define LE_R1_POK       0x03		/* Packet is complete: SOP + EOP */


/*
 *		Transmit Flags
 */
#define LE_T1_OWN	0x80		/* LANCE owns the descriptor */
#define LE_T1_ERR	0x40		/* Error */
#define LE_T1_RES	0x20		/* Reserved, LANCE writes this with a zero */
#define LE_T1_EMORE	0x10		/* More than one retry needed */
#define LE_T1_EONE	0x08		/* One retry needed */
#define LE_T1_EDEF	0x04		/* Deferred */
#define LE_T1_SOP	0x02		/* Start of Packet */
#define LE_T1_EOP	0x01		/* End of Packet */
#define LE_T1_POK	0x03		/* Packet is complete: SOP + EOP */

/*
 *		Error Flags
 */
#define LE_T3_BUF 	0x8000		/* Buffer Error */
#define LE_T3_UFL 	0x4000		/* Underflow Error */
#define LE_T3_LCOL 	0x1000		/* Late Collision */
#define LE_T3_CLOS 	0x0800		/* Loss of Carrier */
#define LE_T3_RTY 	0x0400		/* Retry Error */
#define LE_T3_TDR	0x03ff		/* Time Domain Reflectometry */

/* Miscellaneous useful macros */

#define TX_BUFFS_AVAIL ((lp->tx_old<=lp->tx_new)?\
                        lp->tx_old+lp->tx_ring_mod_mask-lp->tx_new:\
                        lp->tx_old - lp->tx_new-1)

/* The LANCE only uses 24 bit addresses. This does the obvious thing. */
#define LANCE_ADDR(x) ((int)(x) & ~0xff000000)

/* Now the prototypes we export */
extern int lance_open(struct net_device *dev);
extern int lance_close (struct net_device *dev);
extern int lance_start_xmit (struct sk_buff *skb, struct net_device *dev);
extern struct net_device_stats *lance_get_stats (struct net_device *dev);
extern void lance_set_multicast (struct net_device *dev);

#endif /* ndef _7990_H */
