/* Linux/68k Hydra Amiganet board driver v2.1 BETA                          */
/* copyleft by Topi Kanerva (topi@susanna.oulu.fi)                          */
/* also some code & lots of fixes by Timo Rossi (trossi@cc.jyu.fi)          */

/* The code is mostly based on the linux/68k Ariadne driver                 */
/* copyrighted by Geert Uytterhoeven (Geert.Uytterhoeven@cs.kuleuven.ac.be) */
/* and Peter De Schrijver (Peter.DeSchrijver@linux.cc.kuleuven.ac.be)       */

/* This file is subject to the terms and conditions of the GNU General      */
/* Public License.  See the file COPYING in the main directory of the       */
/* Linux distribution for more details.                                     */

/* The Amiganet is a Zorro-II board made by Hydra Systems. It contains a    */
/* NS8390 NIC (network interface controller) clone, 16 or 64K on-board RAM  */
/* and 10BASE-2 (thin coax) and AUI connectors.                             */


#include <linux/module.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/malloc.h>
#include <linux/interrupt.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>

#include <asm/bitops.h>
#include <asm/io.h>
#include <asm/irq.h>

#include <asm/amigaints.h>
#include <asm/amigahw.h>
#include <linux/zorro.h>

#include "hydra.h"


#define HYDRA_DEBUG
#undef HAVE_MULTICAST

#define HYDRA_VERSION "v2.1 BETA"

#undef HYDRA_DEBUG        /* define this for (lots of) debugging information */

#if 0                         /* currently hardwired to one transmit buffer */
	#define TX_RING_SIZE	5
	#define RX_RING_SIZE	16
#else
	#define TX_RING_SIZE 1
	#define RX_RING_SIZE 8
#endif

#define ETHER_MIN_LEN 64
#define ETHER_MAX_LEN 1518
#define ETHER_ADDR_LEN 6


/*
 *   let's define here nice macros for writing and reading NIC registers
 *
 * the CIA accesses here are uses to make sure the minimum time
 * requirement between NIC chip selects is met.
 */
#define WRITE_REG(reg, val) (ciaa.pra, ((u8)(*(nicbase+(reg))=val)))
#define READ_REG(reg) (ciaa.pra, ((u8)(*(nicbase+(reg)))))

/* mask value for the interrupts we use */
#define NIC_INTS (ISR_PRX | ISR_PTX | ISR_RXE | ISR_TXE | ISR_OVW | ISR_CNT)

/* only broadcasts, no promiscuous mode for now */
#define NIC_RCRBITS (0)

/*
 *   Private Device Data
 */
struct hydra_private
{
	u8 *hydra_base;
	u8 *hydra_nic_base;
	u16 tx_page_start;
	u16 rx_page_start;
	u16 rx_page_stop;
	u16 next_pkt;
	struct net_device_stats stats;
	unsigned int key;
};

static int hydra_open(struct device *dev);
static int hydra_start_xmit(struct sk_buff *skb, struct device *dev);
static void hydra_interrupt(int irq, void *data, struct pt_regs *fp);
static void __inline__ hydra_rx(struct device *dev, struct hydra_private *priv, volatile u8 *nicbase);
static int hydra_close(struct device *dev);
static struct net_device_stats *hydra_get_stats(struct device *dev);
#ifdef HAVE_MULTICAST
static void set_multicast_list(struct device *dev, int num_addrs, void *addrs);
#endif


/* this is now coherent with the C version below, */
/* compile the source with -D__USE_ASM__ if you   */
/* want it - it'll only be some 10% faster though */

#if defined (__GNUC__) && defined (__mc68000__) && defined (USE_ASM)

static __inline__ void *memcpyw(u16 *dest, u16 *src, int len)
{
    __asm__("   move.l %0,%/a1; move.l %1,%/a0; move.l %2,%/d0 \n\t"
	    "   cmpi.l #2,%/d0 \n\t"
	    "1: bcs.s  2f \n\t"
            "   move.w %/a0@+,%/a1@+ \n\t"
	    "   subq.l #2,%/d0 \n\t"
	    "   bra.s  1b \n\t"
	    "2: cmpi.l #1,%/d0 \n\t"
	    "   bne.s  3f \n\t"
	    "   move.w %/a0@,%/d0 \n\t"
	    "   swap.w %/d0 \n\t"
	    "   move.b %/d0,%/a1@ \n\t"
	    "3: moveq  #0,%/d0 \n\t"
	  :
	  : "g" (dest), "g" (src), "g" (len)
	  : "a1", "a0", "d0");
    return;
}

#else

/* hydra memory can only be read or written as words or longwords.  */
/* that will mean that we'll have to write a special memcpy for it. */
/* this one here relies on the fact that _writes_ to hydra memory   */
/* are guaranteed to be of even length. (reads can be arbitrary)    */

/*
 *	FIXME: Surely we should be using the OS generic stuff and do
 *
 *	memcpy(dest,src,(len+1)&~1);
 *
 *	Can a 68K guy with this card check that ? - better yet
 *	use a copy/checksum on it.
 */
 
static void memcpyw(u16 *dest, u16 *src, int len)
{
	if(len & 1)
		len++;

	while (len >= 2) 
	{
		*(dest++) = *(src++);
		len -= 2;
	}
}

#endif

__initfunc(int hydra_probe(struct device *dev))
{
	struct hydra_private *priv;
	u32 board;
	unsigned int key;
	const struct ConfigDev *cd;
	int j;

#ifdef HYDRA_DEBUG
 printk("hydra_probe(%x)\n", dev);
#endif

	if ((key = zorro_find(ZORRO_PROD_HYDRA_SYSTEMS_AMIGANET, 0, 0))) 
	{
		cd = zorro_get_board(key);
		if((board = (u32) cd->cd_BoardAddr))
		{
			for(j = 0; j < ETHER_ADDR_LEN; j++)
				dev->dev_addr[j] = *((u8 *)ZTWO_VADDR(board + HYDRA_ADDRPROM + 2*j));
	    
			printk("%s: hydra at 0x%08x, address %02x:%02x:%02x:%02x:%02x:%02x (hydra.c " HYDRA_VERSION ")\n",
				dev->name, (int)board, dev->dev_addr[0], dev->dev_addr[1], dev->dev_addr[2],
				dev->dev_addr[3], dev->dev_addr[4], dev->dev_addr[5]);
			init_etherdev(dev, 0);
	    
			dev->priv = kmalloc(sizeof(struct hydra_private), GFP_KERNEL);
			priv = (struct hydra_private *)dev->priv;
			memset(priv, 0, sizeof(struct hydra_private));
	    
			priv->hydra_base = (u8 *) ZTWO_VADDR(board);
			priv->hydra_nic_base = (u8 *) ZTWO_VADDR(board) + HYDRA_NIC_BASE;
			priv->key = key;
	    
			dev->open = &hydra_open;
			dev->stop = &hydra_close;
			dev->hard_start_xmit = &hydra_start_xmit;
			dev->get_stats = &hydra_get_stats;
#ifdef HAVE_MULTICAST
	 		dev->set_multicast_list = &set_multicast_list;
#endif
	 		
	 		/*
	 		 *	Cannot yet do multicast
	 		 */
	 		dev->flags&=~IFF_MULTICAST;
			zorro_config_board(key, 0);
			return(0);
		}
	}
	return(-ENODEV);
}


static int hydra_open(struct device *dev)
{
	struct hydra_private *priv = (struct hydra_private *)dev->priv;
	volatile u8 *nicbase = priv->hydra_nic_base;
	int i;
    
#ifdef HYDRA_DEBUG
	printk("hydra_open(0x%x)\n", dev);
#endif

	/* first, initialize the private structure */
	priv->tx_page_start = 0;   /* these are 256 byte buffers for NS8390 */
	priv->rx_page_start = 6;
	priv->rx_page_stop  = 62;  /* these values are hard coded for now */

	 /* Reset the NS8390 NIC */
	WRITE_REG(NIC_CR, CR_PAGE0 | CR_NODMA | CR_STOP);

	/* be sure that the NIC is in stopped state */
	while(!(READ_REG(NIC_ISR) & ISR_RST));

	/* word transfer, big endian bytes, loopback, FIFO threshold 4 bytes */
	WRITE_REG(NIC_DCR, DCR_WTS | DCR_BOS | DCR_LS | DCR_FT0);

	/* clear remote byte count registers */
	WRITE_REG(NIC_RBCR0, 0);
	WRITE_REG(NIC_RBCR1, 0);

	/* accept packets addressed to this card and also broadcast packets */
	WRITE_REG(NIC_RCR, NIC_RCRBITS);

	/* enable loopback mode 1 */
	WRITE_REG(NIC_TCR, TCR_LB1);

	/* initialize receive buffer ring */
	WRITE_REG(NIC_PSTART, priv->rx_page_start);
	WRITE_REG(NIC_PSTOP, priv->rx_page_stop);
	WRITE_REG(NIC_BNDRY, priv->rx_page_start);

	/* clear interrupts */
	WRITE_REG(NIC_ISR, 0xff);

	/* enable interrupts */
	WRITE_REG(NIC_IMR, NIC_INTS);

	/* set the ethernet hardware address */
	WRITE_REG(NIC_CR, CR_PAGE1 | CR_NODMA | CR_STOP); /* goto page 1 */

	WRITE_REG(NIC_PAR0, dev->dev_addr[0]);
	WRITE_REG(NIC_PAR1, dev->dev_addr[1]);
	WRITE_REG(NIC_PAR2, dev->dev_addr[2]);
	WRITE_REG(NIC_PAR3, dev->dev_addr[3]);
	WRITE_REG(NIC_PAR4, dev->dev_addr[4]);
	WRITE_REG(NIC_PAR5, dev->dev_addr[5]);

	/* clear multicast hash table */
	for(i = 0; i < 8; i++)
		WRITE_REG(NIC_MAR0 + 2*i, 0);

	priv->next_pkt = priv->rx_page_start+1; /* init our s/w variable */
	WRITE_REG(NIC_CURR, priv->next_pkt);    /* set the next buf for current */

	/* goto page 0, start NIC */
	WRITE_REG(NIC_CR, CR_PAGE0 | CR_NODMA | CR_START);

	/* take interface out of loopback */
	WRITE_REG(NIC_TCR, 0);

	dev->tbusy = 0;
	dev->interrupt = 0;
	dev->start = 1;
    
	if(request_irq(IRQ_AMIGA_PORTS, hydra_interrupt, 0, "Hydra Ethernet", dev))
		return(-EAGAIN);

	MOD_INC_USE_COUNT;

	return(0);
}


static int hydra_close(struct device *dev)
{
	struct hydra_private *priv = (struct hydra_private *)dev->priv;
	volatile u8 *nicbase = priv->hydra_nic_base;
	int n = 5000;

	dev->start = 0;
	dev->tbusy = 1;

#ifdef HYDRA_DEBUG
	printk("%s: Shutting down ethercard\n", dev->name);
	printk("%s: %d packets missed\n", dev->name, priv->stats.rx_missed_errors);
#endif

	WRITE_REG(NIC_CR, CR_PAGE0 | CR_NODMA | CR_STOP);

	/* wait for NIC to stop (what a nice timeout..) */
	while(((READ_REG(NIC_ISR) & ISR_RST) == 0) && --n);
    
	free_irq(IRQ_AMIGA_PORTS, dev);

	MOD_DEC_USE_COUNT;

	return(0);
}


static void hydra_interrupt(int irq, void *data, struct pt_regs *fp)
{
	volatile u8 *nicbase;
  
	struct device *dev = (struct device *) data;
	struct hydra_private *priv;
	u16 intbits;

	if(dev == NULL)
	{
		printk("hydra_interrupt(): irq for unknown device\n");
		return;
	}

	/* this is not likely a problem - i think */
	if(dev->interrupt)
		printk("%s: re-entering the interrupt handler\n", dev->name);

	dev->interrupt = 1;

	priv = (struct hydra_private *) dev->priv;
	nicbase = (u8 *) priv->hydra_nic_base;

	/* select page 0 */
	WRITE_REG(NIC_CR, CR_PAGE0 | CR_START | CR_NODMA);

	intbits = READ_REG(NIC_ISR) & NIC_INTS;
	if(intbits == 0)
        {
		dev->interrupt = 0;
		return;
	}

	/* acknowledge all interrupts, by clearing the interrupt flag */
	WRITE_REG(NIC_ISR, intbits);

	if((intbits & ISR_PTX) && !(intbits & ISR_TXE))
	{
		dev->tbusy = 0;
		mark_bh(NET_BH);
	}
	
	if((intbits & ISR_PRX) && !(intbits & ISR_RXE))/* packet received OK */
		hydra_rx(dev, priv, nicbase);

        if(intbits & ISR_TXE)
		priv->stats.tx_errors++;

        if(intbits & ISR_RXE)
		priv->stats.rx_errors++;

	if(intbits & ISR_CNT) 
	{
		/*
		 * read the tally counters and (currently) ignore the values
		 * might be useful because of bugs of some versions of the 8390 NIC
		 */
#ifdef HYDRA_DEBUG
		printk("hydra_interrupt(): ISR_CNT\n");
#endif
		(void)READ_REG(NIC_CNTR0);
		(void)READ_REG(NIC_CNTR1);
		(void)READ_REG(NIC_CNTR2);
	}
	
	if(intbits & ISR_OVW)
	{
#ifdef HYDRA_DEBUG
		WRITE_REG(NIC_CR, CR_PAGE1 | CR_START | CR_NODMA);
/* another one just too much for me to comprehend - basically this could  */
/* only occur because of invalid access to hydra ram, thus invalidating  */
/* the interrupt bits read - in average usage these do not occur at all */
		printk("hydra_interrupt(): overwrite warning, NIC_ISR %02x, NIC_CURR %02x\n",
			intbits, READ_REG(NIC_CURR));
		WRITE_REG(NIC_CR, CR_PAGE0 | CR_START | CR_NODMA);
#endif
	    

		/* overwrite warning occurred, stop NIC & check the BOUNDARY pointer */
		/* FIXME - real overwrite handling needed !! */

		printk("hydra_interrupt(): overwrite warning, resetting NIC\n");
		WRITE_REG(NIC_CR, CR_PAGE0 | CR_NODMA | CR_STOP);
		while(!(READ_REG(NIC_ISR) & ISR_RST));
		/* wait for NIC to reset */
		WRITE_REG(NIC_DCR, DCR_WTS | DCR_BOS | DCR_LS | DCR_FT0);
		WRITE_REG(NIC_RBCR0, 0);
		WRITE_REG(NIC_RBCR1, 0);
		WRITE_REG(NIC_RCR, NIC_RCRBITS);
		WRITE_REG(NIC_TCR, TCR_LB1);
		WRITE_REG(NIC_PSTART, priv->rx_page_start);
		WRITE_REG(NIC_PSTOP, priv->rx_page_stop);
		WRITE_REG(NIC_BNDRY, priv->rx_page_start);
		WRITE_REG(NIC_ISR, 0xff);
		WRITE_REG(NIC_IMR, NIC_INTS);
		/* currently this _won't_ reset my hydra, even though it is */
		/* basically the same code as in the board init - any ideas? */

		priv->next_pkt = priv->rx_page_start+1; /* init our s/w variable */
		WRITE_REG(NIC_CURR, priv->next_pkt);    /* set the next buf for current */
	    
		WRITE_REG(NIC_CR, CR_PAGE0 | CR_NODMA | CR_START);

		WRITE_REG(NIC_TCR, 0);
	}

	dev->interrupt = 0;
	return;
    }


/*
 * packet transmit routine
 */

static int hydra_start_xmit(struct sk_buff *skb, struct device *dev)
{
	struct hydra_private *priv = (struct hydra_private *)dev->priv;
	volatile u8 *nicbase = priv->hydra_nic_base;
	int len, len1;

	/* Transmitter timeout, serious problems. */

	if(dev->tbusy)
	{
		int tickssofar = jiffies - dev->trans_start;
		if(tickssofar < 20)
			return(1);
		WRITE_REG(NIC_CR, CR_STOP);
		printk("%s: transmit timed out, status %4.4x, resetting.\n", dev->name, 0);
		priv->stats.tx_errors++;
		dev->tbusy = 0;
		dev->trans_start = jiffies;
		return(0);
	}

	len=skb->len;

	/* fill in a tx ring entry */
    
#ifdef HYDRA_DEBUG
	printk("TX pkt type 0x%04x from ", ((u16 *)skb->data)[6]);
	{
		int i;
		u8 *ptr = &((u8 *)skb->data)[6];
		for (i = 0; i < 6; i++)
			printk("%02x", ptr[i]);
	}
	printk(" to ");
	{
		int i;
		u8 *ptr = (u8 *)skb->data;
		for (i = 0; i < 6; i++)
			printk("%02x", ptr[i]);
	}
	printk(" data 0x%08x len %d\n", (int)skb->data, len);
#endif

	/*
	 * make sure that the packet size is at least the minimum
	 * allowed ethernet packet length.
	 * (FIXME: Should also clear the unused space...)
	 * note: minimum packet length is 64, including CRC
	 */
	len1 = len;

	if(len < (ETHER_MIN_LEN-4))
		len = (ETHER_MIN_LEN-1);

	/* make sure we've got an even number of bytes to copy to hydra's mem */
	if(len & 1) len++;

	if((u32)(priv->hydra_base + (priv->tx_page_start << 8)) < 0x80000000)
		printk("weirdness: memcpyw(txbuf, skbdata, len): txbuf = 0x%x\n", (u_int)(priv->hydra_base+(priv->tx_page_start<<8)));

	/* copy the packet data to the transmit buffer 
	   in the ethernet card RAM */
	memcpyw((u16 *)(priv->hydra_base + (priv->tx_page_start << 8)),
		(u16 *)skb->data, len);
	/* clear the unused space */
	for(; len1<len; len1++)
		(u16)*(priv->hydra_base + (priv->tx_page_start<<8) + len1) = 0;
	dev_kfree_skb(skb);

	priv->stats.tx_packets++;

	cli();
	/* make sure we are on the correct page */
	WRITE_REG(NIC_CR, CR_PAGE0 | CR_NODMA | CR_START);

	/* here we configure the transmit page start register etc */
	/* notice that this code is hardwired to one transmit buffer */
	WRITE_REG(NIC_TPSR, priv->tx_page_start);
	WRITE_REG(NIC_TBCR0, len & 0xff);
	WRITE_REG(NIC_TBCR1, len >> 8);

	/* commit the packet to the wire */
	WRITE_REG(NIC_CR, CR_PAGE0 | CR_START | CR_NODMA | CR_TXP);
	sti();

	 dev->trans_start = jiffies;

	return(0);
}


static void __inline__ hydra_rx(struct device *dev, struct hydra_private *priv, volatile u8 *nicbase)
{
	volatile u16 *board_ram_ptr;
	struct sk_buff *skb;
	int hdr_next_pkt, pkt_len, len1, boundary;


	/* remove packet(s) from the ring and commit them to TCP layer */
	WRITE_REG(NIC_CR, CR_PAGE1 | CR_NODMA | CR_START); /* page 1 */
	while(priv->next_pkt != READ_REG(NIC_CURR)) /* should read this only once? */
	{
		board_ram_ptr = (u16 *)(priv->hydra_base + (priv->next_pkt << 8));
	
#ifdef HYDRA_DEBUG
		printk("next_pkt = 0x%x, board_ram_ptr = 0x%x\n", priv->next_pkt, board_ram_ptr);
#endif
	
		/* the following must be done with two steps, or
		   GCC optimizes it to a byte access to Hydra memory,
		   which doesn't work... */
		hdr_next_pkt = board_ram_ptr[0];
		hdr_next_pkt >>= 8;
	
		pkt_len = board_ram_ptr[1];
		pkt_len = ((pkt_len >> 8) | ((pkt_len & 0xff) << 8));
	
#ifdef HYDRA_DEBUG
		printk("hydra_interrupt(): hdr_next_pkt = 0x%02x, len = %d\n", hdr_next_pkt, pkt_len);
#endif
	
		if(pkt_len >= ETHER_MIN_LEN && pkt_len <= ETHER_MAX_LEN)
		{
			/* note that board_ram_ptr is u16 */
			/* CRC is not included in the packet length */
		
			pkt_len -= 4;
			skb = dev_alloc_skb(pkt_len+2);
			if(skb == NULL)
		  	{
				printk(KERN_INFO "%s: memory squeeze, dropping packet.\n", dev->name);
				priv->stats.rx_dropped++;
			}
			else
			{
				skb->dev = dev;
				skb_reserve(skb, 2);
				if(hdr_next_pkt < priv->next_pkt && hdr_next_pkt != priv->rx_page_start)
				{
					/* here, the packet is wrapped */
					len1 = ((priv->rx_page_stop - priv->next_pkt)<<8)-4;
			
					memcpyw((u16 *)skb_put(skb, len1), (u16 *)(board_ram_ptr+2), len1);
					memcpyw((u16 *)skb_put(skb, pkt_len-len1),  (u16 *)(priv->hydra_base+(priv->rx_page_start<<8)), pkt_len-len1);
			
#ifdef HYDRA_DEBUG
					printk("wrapped packet: %d/%d bytes\n", len1, pkt_len-len1);
#endif
				}  /* ... here, packet is not wrapped */
				else
					memcpyw((u16 *) skb_put(skb, pkt_len), (u16 *)(board_ram_ptr+2), pkt_len);
			}
		}
		else
		{
			WRITE_REG(NIC_CR, CR_PAGE1 | CR_START | CR_NODMA);
			printk("hydra_interrupt(): invalid packet len: %d, NIC_CURR = %02x\n", pkt_len, READ_REG(NIC_CURR));
/*
this is the error i kept getting until i switched to 0.9.10. it still doesn't
mean that the bug would have gone away - so be alarmed. the packet is likely
being fetched from a wrong memory location - but why - dunno
   
note-for-v2.1: not really problem anymore. hasn't been for a long time.
*/
		
			WRITE_REG(NIC_CR, CR_PAGE0 | CR_START | CR_NODMA);
			/* should probably reset the NIC here ?? */
		
			hydra_open(dev);  /* FIXME - i shouldn't really be doing this. */
			return;
		}
	
		/* now, update the next_pkt pointer */
		if(hdr_next_pkt < priv->rx_page_stop)
			priv->next_pkt = hdr_next_pkt;
		else
			printk("hydra_interrupt(): invalid next_pkt pointer %d\n", hdr_next_pkt);
	
		/* update the boundary pointer */
		boundary = priv->next_pkt - 1;
		if(boundary < priv->rx_page_start)
			boundary = priv->rx_page_stop - 1;
	
		/* set NIC to page 0 to update the NIC_BNDRY register */
		WRITE_REG(NIC_CR, CR_PAGE0 | CR_START | CR_NODMA);
		WRITE_REG(NIC_BNDRY, boundary);
	
		/* select page1 to access the NIC_CURR register */
		WRITE_REG(NIC_CR, CR_PAGE1 | CR_START | CR_NODMA);
	
	
		skb->protocol = eth_type_trans(skb, dev);
		netif_rx(skb);
		priv->stats.rx_packets++;
	
	}
	return;
}
    

static struct net_device_stats *hydra_get_stats(struct device *dev)
{
	struct hydra_private *priv = (struct hydra_private *)dev->priv;
#if 0
	u8 *board = priv->hydra_base; 

	short saved_addr;
#endif
/* currently does nothing :) i'll finish this later */

	return(&priv->stats);
}

#ifdef HAVE_MULTICAST
static void set_multicast_list(struct device *dev, int num_addrs, void *addrs)
{
	struct hydra_private *priv = (struct hydra_private *)dev->priv;
	u8 *board = priv->hydra_base;

	/* yes, this code is also waiting for someone to complete.. :) */
	/* (personally i don't care about multicasts at all :) */
	return;
}
#endif


#ifdef MODULE
static char devicename[9] = { 0, };

static struct device hydra_dev =
{
	devicename,			/* filled in by register_netdev() */
	0, 0, 0, 0,			/* memory */
	0, 0,				/* base, irq */
	0, 0, 0, NULL, hydra_probe,
};

int init_module(void)
{
	int err;

	if ((err = register_netdev(&hydra_dev))) {
		if (err == -EIO)
			printk("No Hydra board found. Module not loaded.\n");
		return(err);
	}
	return(0);
}

void cleanup_module(void)
{
	struct hydra_private *priv = (struct hydra_private *)hydra_dev.priv;

	unregister_netdev(&hydra_dev);
	zorro_unconfig_board(priv->key, 0);
	kfree(priv);
}

#endif /* MODULE */