/*
 * Crystal CS8900 ethernet controller
 * 
 * Todo:
 * - promiscuous
 *
 * Copyright © 1998 Vita Nuova Limited.  All rights reserved.
 * Revisions Copyright © 2000,2003 Vita Nuova Holdings Limited.  All rights reserved.
 */

#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "../port/netif.h"

#include "etherif.h"

typedef struct Ctlr Ctlr;

/*
 * The CS8900 can be addressed from either  ISA I/O space
 * or ISA memory space at the following virtual addresses,
 * depending on the hardware's wiring.  MEMORY controls
 * use of memory space.
 * The cs8900 address pins are shifted by 1 relative to the CPU.
 */
enum {//18000000
	IsaIOBase		= 0x08000000,
	IsaMemBase	= 0xe0000000,

	IOBase		= 0x300,
	MemBase		= 0xc0000,

	MEMORY = 0,		/* set non-zero if memory mode to be used */
	DORESET = 1,		/* send soft-reset during initialisation */
	DEBUG = 0,
};

#define	IOSHIFT	0	/* was 2 */
#define	IOREG(r) (IsaIOBase+((IOBase+(r))<<IOSHIFT))

/* I/O accesses */
#define	out16(port, val)	(*((ushort *)IOREG(port)) = (val))
#define	in16(port)			*((ushort *)IOREG(port))
#define	in8(port)			*((uchar *)IOREG(port))
#define	regIOw(reg, val)	 do {out16(PpPtr, (reg)|0x3000); out16(PpData, val);} while(0)
#define	regIOr(reg)		(out16(PpPtr, (reg)|0x3000), in16(PpData))
#define	regIOr1(reg)		(out16(PpPtr, (reg)|0x3000), in16(PpData1))

/* Memory accesses */

#define	REGW(reg, val)		*((ushort *)IsaMemBase + MemBase + (reg)) = (val)
#define	REGR(reg)			*((ushort *)IsaMemBase + MemBase + (reg))

enum {					/* I/O Mode Register Offsets */
	RxTxData	= 0x00,		/* receive/transmit data - port 0 */
	RxTxData1 = 0x02,		/* r/t data port 1 */
	TxCmdIO = 0x04,		/* transmit command */
	TxLenIO	= 0x06,		/* transmit length */
	IsqIO	= 0x08,		/* Interrupt status queue */
	PpPtr	= 0x0a,		/* packet page pointer */
	PpData	= 0x0c,		/* packet page data */
	PpData1	= 0x0e,		/* packet page data - port 1*/
};

enum {					/* Memory Mode Register Offsets */
	/* Bus Interface Registers */
	Ern		= 0x0000,		/* EISA registration numberion */
	Pic		= 0x0002,		/* Product identification code */
	Iob		= 0x0020,		/* I/O base address */
	Intr		= 0x0022,		/* interrupt number */
	Mba		= 0x002c,		/* memory base address */
	
	Ecr		= 0x0040,		/* EEPROM command register */
	Edw		= 0x0042,		/* EEPROM data word */
	Rbc		= 0x0050,		/* receive frame byte counter */

	/* Status and Control Registers */
	RxCfg	= 0x0102,
	RxCtl	= 0x0104,
	TxCfg	= 0x0106,
	BufCfg	= 0x010a,
	LineCtl	= 0x0112,
	SelfCtl	= 0x0114,
	BusCtl	= 0x0116,
	TestCtl	= 0x0118,
	Isq		= 0x0120,
	RxEvent	= 0x0124,
	TxEvent	= 0x0128,
	BufEvent	= 0x012c,
	RxMISS	= 0x0130,
	TxCol	= 0x0132,
	LineSt	= 0x0134,
	SelfSt	= 0x0136,
	BusSt	= 0x0138,
	Tdr		= 0x013c,

	/* Initiate Transmit Registers */
	TxCmd	= 0x0144,		/* transmit command */
	TxLen	= 0x0146,		/* transmit length */

	/* Address Filter Registers */
	IndAddr	= 0x0158,		/* individual address registers */

	/* Frame Location */
	RxStatus	= 0x0400,		/* receive status */
	RxLen	= 0x0402,		/* receive length */
	RxFrame	= 0x0404,		/* receive frame location */
	TxFrame	= 0x0a00,		/* transmit frame location */
};

enum {					/* Ecr */
	Addr			= 0x00ff,		/* EEPROM word address (field) */
	Opcode		= 0x0300,		/* command opcode (field) */
		EEread	= 0x0200,
		EEwrite	= 0x0100,
};

enum {					/* Isq */
	Regnum		= 0x003f,		/* register number held by Isq (field) */
		IsqRxEvent	= 0x04,
		IsqTxEvent	= 0x08,
		IsqBufEvent	= 0x0c,
		IsqRxMiss		= 0x10,
		IsqTxCol		= 0x12,
	RegContent 	= 0xffc0,		/* register data contents (field) */
};

enum {					/* RxCfg */
	Skip_1		= 0x0040,
	StreamE		= 0x0080,
	RxOKiE		= 0x0100,
	RxDMAonly	= 0x0200,
	AutoRxDMAE	= 0x0400,
	BufferCRC		= 0x0800,
	CRCerroriE	= 0x1000,
	RuntiE		= 0x2000,
	ExtradataiE	= 0x4000,
};

enum {					/* RxEvent */
	IAHash		= 0x0040,
	Dribblebits	= 0x0080,
	RxOK		= 0x0100,
	Hashed		= 0x0200,
	IndividualAdr	= 0x0400,
	Broadcast		= 0x0800,
	CRCerror		= 0x1000,
	Runt			= 0x2000,
	Extradata		= 0x4000,
};

enum {					/* RxCtl */
	IAHashA		= 0x0040,
	PromiscuousA	= 0x0080,
	RxOKA		= 0x0100,
	MulticastA	= 0x0200,
	IndividualA	= 0x0400,
	BroadcastA	= 0x0800,
	CRCerrorA	= 0x1000,
	RuntA		= 0x2000,
	ExtradataA	= 0x4000,
};

enum {					/* TxCfg */
	LossofCRSiE	= 0x0040,
	SQEerroriE	= 0x0080,
	TxOKiE		= 0x0100,
	OutofWindowiE	= 0x0200,
	JabberiE		= 0x0400,
	AnycolliE		= 0x0800,
	Coll16iE		= 0x8000,
};

enum {					/* TxEvent */
	LossofCRS	= 0x0040,
	SQEerror		= 0x0080,
	TxOK		= 0x0100,
	OutofWindow	= 0x0200,
	Jabber		= 0x0400,
	NTxCols		= 0x7800,		/* number of Tx collisions (field) */
	coll16		= 0x8000,
};

enum {					/* BufCfg */
	SWintX		= 0x0040,
	RxDMAiE		= 0x0080,
	Rdy4TxiE		= 0x0100,
	TxUnderruniE	= 0x0200,
	RxMissiE		= 0x0400,
	Rx128iE		= 0x0800,
	TxColOvfiE	= 0x1000,
	MissOvfloiE	= 0x2000,
	RxDestiE		= 0x8000,
};

enum {					/* BufEvent */
	SWint		= 0x0040,
	RxDMAFrame	= 0x0080,
	Rdy4Tx		= 0x0100,
	TxUnderrun	= 0x0200,
	RxMiss		= 0x0400,
	Rx128		= 0x0800,
	RxDest		= 0x8000,
};

enum {					/* RxMiss */
	MissCount	= 0xffc0,
};

enum {					/* TxCol */
	ColCount	= 0xffc0,
};

enum {					/* LineCtl */
	SerRxOn		= 0x0040,
	SerTxOn		= 0x0080,
	Iface			= 0x0300,		/* (field) 01 - AUI, 00 - 10BASE-T, 10 - Auto select */
	ModBackoffE	= 0x0800,
	PolarityDis	= 0x1000,
	DefDis		= 0x2000,
	LoRxSquelch	= 0x4000,
};

enum {					/* LineSt */
	LinkOK		= 0x0080,
	AUI			= 0x0100,
	TenBT		= 0x0200,
	PolarityOK	= 0x1000,
	CRS			= 0x4000,
};

enum {					/* SelfCtl */
	RESET		= 0x0040,
	SWSuspend	= 0x0100,
	HWSleepE		= 0x0200,
	HWStandbyE	= 0x0400,
};

enum {					/* SelfSt */
	Active3V		= 0x0040,
	INITD		= 0x0080,
	SIBUSY		= 0x0100,
	EepromPresent	= 0x0200,
	EepromOK	= 0x0400,
	ElPresent		= 0x0800,
	EeSize		= 0x1000,
};

enum {					/* BusCtl */
	ResetRxDMA	= 0x0040,
	UseSA		= 0x0200,
	MemoryE		= 0x0400,
	DMABurst		= 0x0800,
	EnableIRQ		= 0x8000,
};

enum {					/* BusST */
	TxBidErr		= 0x0080,
	Rdy4TxNOW	= 0x0100,
};

enum {					/* TestCtl */
	FDX			= 0x4000,		/* full duplex */
};

enum {					/* TxCmd */
	TxStart		= 0x00c0,		/* bytes before transmit starts (field) */
		TxSt5	= 0x0000,		/* start after 5 bytes */
		TxSt381	= 0x0040,		/* start after 381 bytes */
		TxSt1021	= 0x0080,		/* start after 1021 bytes */
		TxStAll	= 0x00c0,		/* start after the entire frame is in the cs8900 */
	Force		= 0x0100,
	Onecoll		= 0x0200,
	InhibitCRC	= 0x1000,
	TxPadDis		= 0x2000,
};

enum {	/* EEPROM format */
	Edataoff	= 0x1C,	/* start of data (ether address) */
	Edatalen	= 0x14,	/* data count in 16-bit words */
};

struct Ctlr {
	Lock;
	Block*	waiting;	/* waiting for space in FIFO */
	int	model;
	int	rev;

	ulong	collisions;
};

static void
regw(int reg, int val)
{
	if(DEBUG)
		print("r%4.4ux <- %4.4ux\n", reg, val);
	if(MEMORY){
		REGW(reg, val);
	}else{
		out16(PpPtr, reg);
		out16(PpData, val);
	}
}

static int
regr(int reg)
{
	int v;

	if(MEMORY)
		return REGR(reg);
	out16(PpPtr, reg);
	v = in16(PpData);
	if(DEBUG)
		print("r%4.4ux = %4.4ux\n", reg, v);
	return v;
}

/*
 * copy frames in and out, accounting for shorts aligned as longs in IO memory
 */

static void
copypktin(void *ad, int len)
{
	ushort *s, *d;
	int ns;

	if(!MEMORY){
		d = ad;
		/*
		 * contrary to data sheet DS271PP3 pages 77-78,
		 * the data is not preceded by status & length
		 * perhaps because it has been read directly.
		 */
		for(ns = len>>1; --ns >= 0;)
			*d++ = in16(RxTxData);
		if(len & 1)
			*(uchar*)d = in16(RxTxData);
		return;
	}
	d = ad;
	s = (ushort*)IsaMemBase + MemBase + RxFrame;
	for(ns = len>>1; --ns >= 0;){
		*d++ = *s;
		s += 2;
	}
	if(len & 1)
		*(uchar*)d = *s;
}

static void
copypktout(void *as, int len)
{
	ushort *s, *d;
	int ns;

	if(!MEMORY){
		s = as;
		ns = (len+1)>>1;
		while(--ns >= 0)
			out16(RxTxData, *s++);
		return;
	}
	s = as;
	d = (ushort*)IsaMemBase + MemBase + TxFrame;
	ns = (len+1)>>1;
	while(--ns >= 0){
		*d = *s++;
		d += 2;
	}
}

static long
ifstat(Ether* ether, void* a, long n, ulong offset)
{
	Ctlr *ctlr;
	char *p;
	int len;

	if(n == 0)
		return 0;

	ctlr = ether->ctlr;
	p = malloc(READSTR);
	len = snprint(p, READSTR, "Overflow: %ud\n", ether->overflows);
	len += snprint(p+len, READSTR-len, "CRC Error: %ud\n", ether->crcs);
	snprint(p+len, READSTR-len, "Collision Seen: %lud\n", ctlr->collisions);

	n = readstr(offset, a, n, p);
	free(p);

	return n;
}

static void
promiscuous(void* arg, int on)
{
	USED(arg, on);
}

static void
attach(Ether *ether)
{
	int reg;

	USED(ether);
	/* enable transmit and receive */
	reg = regr(BusCtl);
	regw(BusCtl, reg|EnableIRQ);
	reg = regr(LineCtl);
	regw(LineCtl, reg|SerRxOn|SerTxOn);
	if(DEBUG){
		iprint("bus=%4.4ux line=%4.4ux\n", regr(BusCtl), regr(LineCtl));
		iprint("rc=%4.4ux tc=%4.4ux bc=%4.4ux\n", regr(RxCfg), regr(TxCfg), regr(BufCfg));
	}
}

static void
txstart(Ether *ether, int dowait)
{
	int len, status;
	Ctlr *ctlr;
	Block *b;

	ctlr = ether->ctlr;
	for(;;){
		if((b = ctlr->waiting) == nil){
			if((b = qget(ether->oq)) == nil)
				break;
		}else{
			if(!dowait)
				break;
			ctlr->waiting = nil;
		}
		len = BLEN(b);
		if(MEMORY){
			regw(TxCmd, TxSt381);
			regw(TxLen, len);
		}else{
			out16(TxCmdIO, TxStAll);
			out16(TxLenIO, len);
		}
		status = regr(BusSt);
		if((status & Rdy4TxNOW) == 0) {
			ctlr->waiting = b;
			break;
		}
		/*
		 * Copy the packet to the transmit buffer.
		 */
		copypktout(b->rp, len);
		freeb(b);
	}
}

static void
transmit(Ether *ether)
{
	Ctlr *ctlr;

	ctlr = ether->ctlr;
	ilock(ctlr);
	txstart(ether, 0);
	iunlock(ctlr);
}

static void
interrupt(Ureg*, void *arg)
{
	Ether *ether;
	Ctlr *ctlr;
	int len, events, status;
	Block *b;

	ether = arg;
	ctlr = ether->ctlr;
	ilock(ctlr);
	while((events = (MEMORY?regr(Isq):in16(IsqIO))) != 0) {
		status = events&RegContent;
		if(DEBUG)
			iprint("status %4.4ux event %4.4ux\n", status, events);
		switch(events&Regnum) {

		case IsqBufEvent:
			if(status&Rdy4Tx) {
				if((b = ctlr->waiting) != nil){
					ctlr->waiting = nil;
					copypktout(b->rp, BLEN(b));
					freeb(b);
					/* wait for IsqTxEvent to send remaining packets in txstart */
				}else
					txstart(ether, 0);
			}
			break;

		case IsqRxEvent:
			if(status&RxOK) {
				len = regr(RxLen);
				if(DEBUG)
					iprint("rxlen=%d\n", len);
				if((b = iallocb(len)) != 0) {
					copypktin(b->wp, len);
					b->wp += len;
					etheriq(ether, b, 1);
				}
			}
			break;

		case IsqTxEvent:
			if(status&TxOK)
				txstart(ether, 1);
			break;

		case IsqRxMiss:
			ether->overflows++;
			break;

		case IsqTxCol:
			ctlr->collisions++;
			break;
		}
	}
	iunlock(ctlr);
}

static int
eepromwait(void)
{
	int i;

	for(i=0; i<100000; i++)
		if((regIOr(SelfSt) & SIBUSY) == 0)
			return 0;
	return -1;
}

static int
eepromrd(void *buf, int off, int n)
{
	int i;
	ushort *p;

	p = buf;
	n /= 2;
	for(i=0; i<n; i++){
		if(eepromwait() < 0)
			return -1;
		regIOw(Ecr, EEread | (off+i));
		if(eepromwait() < 0)
			return -1;
		p[i] = regIOr(Edw);
	}
	return 0;
}

static int
reset(Ether* ether)
{
	int i, reg, easet;
	uchar ea[Eaddrlen];
	ushort buf[Edatalen];
	Ctlr *ctlr;

	if(!MEMORY)
		mmuphysmap(IsaIOBase, 64*1024);

	delay(120);	/* allow time for chip to reset */

	if(0){
		*(ushort*)IsaIOBase = 0xDEAD;	/* force rubbish on bus */
		for(i=0; i<100; i++){
			if(in16(PpPtr) == 0x3000)
				break;
			delay(1);
		}
		if(i>=100){
			iprint("failed init: reg(0xA): %4.4ux, should be 0x3000\n", in16(PpPtr));
			return -1;
		}
	}
iprint("8900: %4.4ux (selfst) %4.4ux (linest)\n", regIOr(SelfSt), regIOr(LineSt));
iprint("8900: %4.4ux %4.4ux\n", regIOr(Ern), regIOr(Pic));

	/* 
	 * Identify the chip by reading the Pic register.
	 * The EISA registration number is in the low word
	 * and the product identification code in the high code.
	 * The ERN for Crystal Semiconductor is 0x630e.
	 * Bits 0-7 and 13-15 of the Pic should be zero for a CS8900.
	 */
	if(regIOr(Ern) != 0x630e || (regIOr(Pic) & 0xe0ff) != 0)
		return -1;

	if(ether->ctlr == nil)
		ether->ctlr = malloc(sizeof(Ctlr));
	ctlr = ether->ctlr;

	reg = regIOr(Pic);
	ctlr->model = reg>>14;
	ctlr->rev = (reg >> 8) & 0x1F;

	ether->mbps = 10;

	memset(ea, 0, Eaddrlen);
	easet = memcmp(ea, ether->ea, Eaddrlen);
	memset(buf, 0, sizeof(buf));
	if(regIOr(SelfSt) & EepromPresent) {	/* worth a look */
		if(eepromrd(buf, Edataoff, sizeof(buf)) >= 0){
			for(i=0; i<3; i++){
				ether->ea[2*i] = buf[i];
				ether->ea[2*i+1] = buf[i] >> 8;
			}
			easet = 1;
		}else
			iprint("cs8900: can't read EEPROM\n");
	}
	if(!easet){
		iprint("cs8900: ethernet address not configured\n");
		return -1;
	}
	memmove(ea, ether->ea, Eaddrlen);

	if(DORESET){
		/*
		 * Reset the chip and ensure 16-bit mode operation
		 */
		regIOw(SelfCtl, RESET);
		delay(10);
		i=in8(PpPtr); 	USED(i);
		i=in8(PpPtr+1); USED(i);
		i=in8(PpPtr); 	USED(i);
		i=in8(PpPtr+1);	USED(i);

		/*
		 * Wait for initialisation and EEPROM reads to complete
		 */
		i=0;
		for(;;) {
			short st = regIOr(SelfSt);
			if((st&SIBUSY) == 0 && st&INITD)
				break;
			if(i++ > 1000000)
				panic("cs8900: initialisation failed");
		}
	}

	if(MEMORY){
		/*
		 * Enable memory mode operation.
		 */
		regIOw(Mba, MemBase & 0xffff);
		regIOw(Mba+2, MemBase >> 16);
		regIOw(BusCtl, MemoryE|UseSA);
	}

	/*
	 * Enable 10BASE-T half duplex, transmit in interrupt mode
	 */
	reg = regr(LineCtl);
	regw(LineCtl, reg&~Iface);
	reg = regr(TestCtl);
	if(ether->fullduplex)
		regw(TestCtl, reg|FDX);
	else
		regw(TestCtl, reg&~FDX);
	regw(BufCfg, Rdy4TxiE|TxUnderruniE);
	regw(TxCfg, TxOKiE|AnycolliE|LossofCRSiE|Coll16iE);
	regw(RxCfg, RxOKiE|CRCerroriE|RuntiE|ExtradataiE);
	regw(RxCtl, RxOKA|IndividualA|BroadcastA);

	for(i=0; i<Eaddrlen; i+=2)
		regw(IndAddr+i, ea[i] | (ea[i+1] << 8));

	/* IRQ tied to INTRQ0 */
	regw(Intr, 0);

	/*
	 * Linkage to the generic ethernet driver.
	 */
	ether->attach = attach;
	ether->transmit = transmit;
	ether->interrupt = interrupt;
	ether->ifstat = ifstat;

	ether->arg = ether;
	ether->promiscuous = promiscuous;

	ether->itype = BusGPIOrising;	/* TO DO: this shouldn't be done here */

	return 0;
}

void
ether8900link(void)
{
	addethercard("CS8900",  reset);
}