path: root/openwrt/package/linux/kernel-source/drivers/net/hnd/hnddma.c

/*
 * Generic Broadcom Home Networking Division (HND) DMA module.
 * This supports the following chips: BCM42xx, 44xx, 47xx .
 *
 * Copyright 2004, Broadcom Corporation
 * All Rights Reserved.
 * 
 * THIS SOFTWARE IS OFFERED "AS IS", AND BROADCOM GRANTS NO WARRANTIES OF ANY
 * KIND, EXPRESS OR IMPLIED, BY STATUTE, COMMUNICATION OR OTHERWISE. BROADCOM
 * SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A SPECIFIC PURPOSE OR NONINFRINGEMENT CONCERNING THIS SOFTWARE.
 *
 * $Id$
 */

#include <typedefs.h>
#include <osl.h>
#include <bcmendian.h>
#include <bcmutils.h>

struct dma_info;	/* forward declaration */
#define di_t struct dma_info
#include <hnddma.h>

/* debug/trace */
#define	DMA_ERROR(args)
#define	DMA_TRACE(args)

/* default dma message level(if input msg_level pointer is null in dma_attach()) */
static uint dma_msg_level = 0;

#define	MAXNAMEL	8
#define	MAXDD		(DMAMAXRINGSZ / sizeof (dmadd_t))

/* dma engine software state */
typedef struct dma_info {
	hnddma_t	hnddma;		/* exported structure */
	uint		*msg_level;	/* message level pointer */

	char		name[MAXNAMEL];	/* callers name for diag msgs */
	void		*drv;		/* driver handle */
	void		*dev;		/* device handle */
	dmaregs_t	*regs;		/* dma engine registers */

	dmadd_t		*txd;		/* pointer to chip-specific tx descriptor ring */
	uint		txin;		/* index of next descriptor to reclaim */
	uint		txout;		/* index of next descriptor to post */
	uint		txavail;	/* # free tx descriptors */
	void		*txp[MAXDD];	/* parallel array of pointers to packets */
	ulong		txdpa;		/* physical address of descriptor ring */
	uint		txdalign;	/* #bytes added to alloc'd mem to align txd */

	dmadd_t		*rxd;		/* pointer to chip-specific rx descriptor ring */
	uint		rxin;		/* index of next descriptor to reclaim */
	uint		rxout;		/* index of next descriptor to post */
	void		*rxp[MAXDD];	/* parallel array of pointers to packets */
	ulong		rxdpa;		/* physical address of descriptor ring */
	uint		rxdalign;	/* #bytes added to alloc'd mem to align rxd */

	/* tunables */
	uint		ntxd;		/* # tx descriptors */
	uint		nrxd;		/* # rx descriptors */
	uint		rxbufsize;	/* rx buffer size in bytes */
	uint		nrxpost;	/* # rx buffers to keep posted */
	uint		rxoffset;	/* rxcontrol offset */
	uint		ddoffset;	/* add to get dma address of descriptor ring */
	uint		dataoffset;	/* add to get dma address of data buffer */
} dma_info_t;

/* descriptor bumping macros */
#define	TXD(x)		((x) & (di->ntxd - 1))
#define	RXD(x)		((x) & (di->nrxd - 1))
#define	NEXTTXD(i)	TXD(i + 1)
#define	PREVTXD(i)	TXD(i - 1)
#define	NEXTRXD(i)	RXD(i + 1)
#define	NTXDACTIVE(h, t)	TXD(t - h)
#define	NRXDACTIVE(h, t)	RXD(t - h)

/* macros to convert between byte offsets and indexes */
#define	B2I(bytes)	((bytes) / sizeof (dmadd_t))
#define	I2B(index)	((index) * sizeof (dmadd_t))

void*
dma_attach(void *drv, void *dev, char *name, dmaregs_t *regs, uint ntxd, uint nrxd,
	uint rxbufsize, uint nrxpost, uint rxoffset, uint ddoffset, uint dataoffset, uint *msg_level)
{
	dma_info_t *di;
	void *va;

	ASSERT(ntxd <= MAXDD);
	ASSERT(nrxd <= MAXDD);

	/* allocate private info structure */
	if ((di = MALLOC(sizeof (dma_info_t))) == NULL)
		return (NULL);
	bzero((char*)di, sizeof (dma_info_t));

	/* set message level */
	di->msg_level = msg_level ? msg_level : &dma_msg_level;

	DMA_TRACE(("%s: dma_attach: drv 0x%x dev 0x%x regs 0x%x ntxd %d nrxd %d rxbufsize %d nrxpost %d rxoffset %d ddoffset 0x%x dataoffset 0x%x\n", name, (uint)drv, (uint)dev, (uint)regs, ntxd, nrxd, rxbufsize, nrxpost, rxoffset, ddoffset, dataoffset));

	/* make a private copy of our callers name */
	strncpy(di->name, name, MAXNAMEL);
	di->name[MAXNAMEL-1] = '\0';

	di->drv = drv;
	di->dev = dev;
	di->regs = regs;

	/* allocate transmit descriptor ring */
	if (ntxd) {
		if ((va = DMA_ALLOC_CONSISTENT(dev, (DMAMAXRINGSZ + DMARINGALIGN), &di->txdpa)) == NULL)
			goto fail;
		di->txd = (dmadd_t*) ROUNDUP(va, DMARINGALIGN);
		di->txdalign = ((uint)di->txd - (uint)va);
		di->txdpa = di->txdpa + di->txdalign;
		ASSERT(ISALIGNED(di->txd, DMARINGALIGN));
	}

	/* allocate receive descriptor ring */
	if (nrxd) {
		if ((va = DMA_ALLOC_CONSISTENT(dev, (DMAMAXRINGSZ + DMARINGALIGN), &di->rxdpa)) == NULL)
			goto fail;
		di->rxd = (dmadd_t*) ROUNDUP(va, DMARINGALIGN);
		di->rxdalign = ((uint)di->rxd - (uint)va);
		di->rxdpa = di->rxdpa + di->rxdalign;
		ASSERT(ISALIGNED(di->rxd, DMARINGALIGN));
	}

	/* save tunables */
	di->ntxd = ntxd;
	di->nrxd = nrxd;
	di->rxbufsize = rxbufsize;
	di->nrxpost = nrxpost;
	di->rxoffset = rxoffset;
	di->ddoffset = ddoffset;
	di->dataoffset = dataoffset;

	return ((void*)di);

fail:
	dma_detach((void*)di);
	return (NULL);
}

/* may be called with core in reset */
void
dma_detach(dma_info_t *di)
{
	if (di == NULL)
		return;

	DMA_TRACE(("%s: dma_detach\n", di->name));

	/* shouldn't be here if descriptors are unreclaimed */
	ASSERT(di->txin == di->txout);
	ASSERT(di->rxin == di->rxout);

	/* free dma descriptor rings */
	if (di->txd)
		DMA_FREE_CONSISTENT(di->dev, (void *)((uint)di->txd - di->txdalign), (DMAMAXRINGSZ + DMARINGALIGN), di->txdpa);
	if (di->rxd)
		DMA_FREE_CONSISTENT(di->dev, (void *)((uint)di->rxd - di->rxdalign), (DMAMAXRINGSZ + DMARINGALIGN), di->rxdpa);

	/* free our private info structure */
	MFREE((void*)di, sizeof (dma_info_t));
}


void
dma_txreset(dma_info_t *di)
{
	uint32 status;

	DMA_TRACE(("%s: dma_txreset\n", di->name));

	/* suspend tx DMA first */
	W_REG(&di->regs->xmtcontrol, XC_SE);
	SPINWAIT((status = (R_REG(&di->regs->xmtstatus) & XS_XS_MASK)) != XS_XS_DISABLED &&
		 status != XS_XS_IDLE &&
		 status != XS_XS_STOPPED,
		 10000);

	W_REG(&di->regs->xmtcontrol, 0);
	SPINWAIT((status = (R_REG(&di->regs->xmtstatus) & XS_XS_MASK)) != XS_XS_DISABLED,
		 10000);

	if (status != XS_XS_DISABLED) {
		DMA_ERROR(("%s: dma_txreset: dma cannot be stopped\n", di->name));
	}

	/* wait for the last transaction to complete */
	OSL_DELAY(300);
}

void
dma_rxreset(dma_info_t *di)
{
	uint32 status;

	DMA_TRACE(("%s: dma_rxreset\n", di->name));

	W_REG(&di->regs->rcvcontrol, 0);
	SPINWAIT((status = (R_REG(&di->regs->rcvstatus) & RS_RS_MASK)) != RS_RS_DISABLED,
		 10000);

	if (status != RS_RS_DISABLED) {
		DMA_ERROR(("%s: dma_rxreset: dma cannot be stopped\n", di->name));
	}
}

void
dma_txinit(dma_info_t *di)
{
	DMA_TRACE(("%s: dma_txinit\n", di->name));

	di->txin = di->txout = 0;
	di->txavail = di->ntxd - 1;

	/* clear tx descriptor ring */
	BZERO_SM((void*)di->txd, (di->ntxd * sizeof (dmadd_t)));

	W_REG(&di->regs->xmtcontrol, XC_XE);
	W_REG(&di->regs->xmtaddr, (di->txdpa + di->ddoffset));
}

bool
dma_txenabled(dma_info_t *di)
{
	uint32 xc;

	/* If the chip is dead, it is not enabled :-) */
	xc = R_REG(&di->regs->xmtcontrol);
	return ((xc != 0xffffffff) && (xc & XC_XE));
}

void
dma_txsuspend(dma_info_t *di)
{
	DMA_TRACE(("%s: dma_txsuspend\n", di->name));
	OR_REG(&di->regs->xmtcontrol, XC_SE);
}

void
dma_txresume(dma_info_t *di)
{
	DMA_TRACE(("%s: dma_txresume\n", di->name));
	AND_REG(&di->regs->xmtcontrol, ~XC_SE);
}

bool
dma_txsuspended(dma_info_t *di)
{
	if (!(R_REG(&di->regs->xmtcontrol) & XC_SE))
		return 0;
	
	if ((R_REG(&di->regs->xmtstatus) & XS_XS_MASK) != XS_XS_IDLE)
		return 0;

	OSL_DELAY(2);
	return ((R_REG(&di->regs->xmtstatus) & XS_XS_MASK) == XS_XS_IDLE);
}

bool
dma_txstopped(dma_info_t *di)
{
	return ((R_REG(&di->regs->xmtstatus) & XS_XS_MASK) == XS_XS_STOPPED);
}

bool
dma_rxstopped(dma_info_t *di)
{
	return ((R_REG(&di->regs->rcvstatus) & RS_RS_MASK) == RS_RS_STOPPED);
}

void
dma_fifoloopbackenable(dma_info_t *di)
{
	DMA_TRACE(("%s: dma_fifoloopbackenable\n", di->name));
	OR_REG(&di->regs->xmtcontrol, XC_LE);
}

void
dma_rxinit(dma_info_t *di)
{
	DMA_TRACE(("%s: dma_rxinit\n", di->name));

	di->rxin = di->rxout = 0;

	/* clear rx descriptor ring */
	BZERO_SM((void*)di->rxd, (di->nrxd * sizeof (dmadd_t)));

	dma_rxenable(di);
	W_REG(&di->regs->rcvaddr, (di->rxdpa + di->ddoffset));
}

void
dma_rxenable(dma_info_t *di)
{
	DMA_TRACE(("%s: dma_rxenable\n", di->name));
	W_REG(&di->regs->rcvcontrol, ((di->rxoffset << RC_RO_SHIFT) | RC_RE));
}

bool
dma_rxenabled(dma_info_t *di)
{
	uint32 rc;

	rc = R_REG(&di->regs->rcvcontrol);
	return ((rc != 0xffffffff) && (rc & RC_RE));
}

/*
 * The BCM47XX family supports full 32bit dma engine buffer addressing so
 * dma buffers can cross 4 Kbyte page boundaries.
 */
int
dma_txfast(dma_info_t *di, void *p0, uint32 coreflags)
{
	void *p, *next;
	uchar *data;
	uint len;
	uint txout;
	uint32 ctrl;
	uint32 pa;

	DMA_TRACE(("%s: dma_txfast\n", di->name));

	txout = di->txout;
	ctrl = 0;

	/*
	 * Walk the chain of packet buffers
	 * allocating and initializing transmit descriptor entries.
	 */
	for (p = p0; p; p = next) {
		data = PKTDATA(di->drv, p);
		len = PKTLEN(di->drv, p);
		next = PKTNEXT(di->drv, p);

		/* return nonzero if out of tx descriptors */
		if (NEXTTXD(txout) == di->txin)
			goto outoftxd;

		if (len == 0)
			continue;

		/* get physical address of buffer start */
		pa = (uint32) DMA_MAP(di->dev, data, len, DMA_TX, p);

		/* build the descriptor control value */
		ctrl = len & CTRL_BC_MASK;

		ctrl |= coreflags;
		
		if (p == p0)
			ctrl |= CTRL_SOF;
		if (next == NULL)
			ctrl |= (CTRL_IOC | CTRL_EOF);
		if (txout == (di->ntxd - 1))
			ctrl |= CTRL_EOT;

		/* init the tx descriptor */
		W_SM(&di->txd[txout].ctrl, BUS_SWAP32(ctrl));
		W_SM(&di->txd[txout].addr, BUS_SWAP32(pa + di->dataoffset));

		ASSERT(di->txp[txout] == NULL);

		txout = NEXTTXD(txout);
	}

	/* if last txd eof not set, fix it */
	if (!(ctrl & CTRL_EOF))
		W_SM(&di->txd[PREVTXD(txout)].ctrl, BUS_SWAP32(ctrl | CTRL_IOC | CTRL_EOF));

	/* save the packet */
	di->txp[PREVTXD(txout)] = p0;

	/* bump the tx descriptor index */
	di->txout = txout;

	/* kick the chip */
	W_REG(&di->regs->xmtptr, I2B(txout));

	/* tx flow control */
	di->txavail = di->ntxd - NTXDACTIVE(di->txin, di->txout) - 1;

	return (0);

outoftxd:
	DMA_ERROR(("%s: dma_txfast: out of txds\n", di->name));
	PKTFREE(di->drv, p0, TRUE);
	di->txavail = 0;
	di->hnddma.txnobuf++;
	return (-1);
}

#define	PAGESZ		4096
#define	PAGEBASE(x)	((uint)(x) & ~4095)

/*
 * Just like above except go through the extra effort of splitting
 * buffers that cross 4Kbyte boundaries into multiple tx descriptors.
 */
int
dma_tx(dma_info_t *di, void *p0, uint32 coreflags)
{
	void *p, *next;
	uchar *data;
	uint plen, len;
	uchar *page, *start, *end;
	uint txout;
	uint32 ctrl;
	uint32 pa;

	DMA_TRACE(("%s: dma_tx\n", di->name));

	txout = di->txout;
	ctrl = 0;

	/*
	 * Walk the chain of packet buffers
	 * splitting those that cross 4 Kbyte boundaries
	 * allocating and initializing transmit descriptor entries.
	 */
	for (p = p0; p; p = next) {
		data = PKTDATA(di->drv, p);
		plen = PKTLEN(di->drv, p);
		next = PKTNEXT(di->drv, p);

		if (plen == 0)
			continue;

		for (page = (uchar*)PAGEBASE(data);
			page <= (uchar*)PAGEBASE(data + plen - 1);
			page += PAGESZ) {

			/* return nonzero if out of tx descriptors */
			if (NEXTTXD(txout) == di->txin)
				goto outoftxd;

			start = (page == (uchar*)PAGEBASE(data))?  data: page;
			end = (page == (uchar*)PAGEBASE(data + plen))?
				(data + plen): (page + PAGESZ);
			len = end - start;

			/* build the descriptor control value */
			ctrl = len & CTRL_BC_MASK;

			ctrl |= coreflags;

			if ((p == p0) && (start == data))
				ctrl |= CTRL_SOF;
			if ((next == NULL) && (end == (data + plen)))
				ctrl |= (CTRL_IOC | CTRL_EOF);
			if (txout == (di->ntxd - 1))
				ctrl |= CTRL_EOT;

			/* get physical address of buffer start */
			pa = (uint32) DMA_MAP(di->dev, start, len, DMA_TX, p);

			/* init the tx descriptor */
			W_SM(&di->txd[txout].ctrl, BUS_SWAP32(ctrl));
			W_SM(&di->txd[txout].addr, BUS_SWAP32(pa + di->dataoffset));

			ASSERT(di->txp[txout] == NULL);

			txout = NEXTTXD(txout);
		}
	}

	/* if last txd eof not set, fix it */
	if (!(ctrl & CTRL_EOF))
		W_SM(&di->txd[PREVTXD(txout)].ctrl, BUS_SWAP32(ctrl | CTRL_IOC | CTRL_EOF));

	/* save the packet */
	di->txp[PREVTXD(txout)] = p0;

	/* bump the tx descriptor index */
	di->txout = txout;

	/* kick the chip */
	W_REG(&di->regs->xmtptr, I2B(txout));

	/* tx flow control */
	di->txavail = di->ntxd - NTXDACTIVE(di->txin, di->txout) - 1;

	return (0);

outoftxd:
	DMA_ERROR(("%s: dma_tx: out of txds\n", di->name));
	PKTFREE(di->drv, p0, TRUE);
	di->txavail = 0;
	di->hnddma.txnobuf++;
	return (-1);
}

/* returns a pointer to the next frame received, or NULL if there are no more */
void*
dma_rx(dma_info_t *di)
{
	void *p;
	uint len;
	int skiplen = 0;

	while ((p = dma_getnextrxp(di, FALSE))) {
		/* skip giant packets which span multiple rx descriptors */
		if (skiplen > 0) {
			skiplen -= di->rxbufsize;
			if (skiplen < 0)
				skiplen = 0;
			PKTFREE(di->drv, p, FALSE);
			continue;
		}

		len = ltoh16(*(uint16*)(PKTDATA(di->drv, p)));
		DMA_TRACE(("%s: dma_rx len %d\n", di->name, len));

		/* bad frame length check */
		if (len > (di->rxbufsize - di->rxoffset)) {
			DMA_ERROR(("%s: dma_rx: bad frame length (%d)\n", di->name, len));
			if (len > 0)
				skiplen = len - (di->rxbufsize - di->rxoffset);
			PKTFREE(di->drv, p, FALSE);
			di->hnddma.rxgiants++;
			continue;
		}

		/* set actual length */
		PKTSETLEN(di->drv, p, (di->rxoffset + len));

		break;
	}

	return (p);
}

/* post receive buffers */
void
dma_rxfill(dma_info_t *di)
{
	void *p;
	uint rxin, rxout;
	uint ctrl;
	uint n;
	uint i;
	uint32 pa;
	uint rxbufsize;

	/*
	 * Determine how many receive buffers we're lacking
	 * from the full complement, allocate, initialize,
	 * and post them, then update the chip rx lastdscr.
	 */

	rxin = di->rxin;
	rxout = di->rxout;
	rxbufsize = di->rxbufsize;

	n = di->nrxpost - NRXDACTIVE(rxin, rxout);

	DMA_TRACE(("%s: dma_rxfill: post %d\n", di->name, n));

	for (i = 0; i < n; i++) {
		if ((p = PKTGET(di->drv, rxbufsize, FALSE)) == NULL) {
			DMA_ERROR(("%s: dma_rxfill: out of rxbufs\n", di->name));
			di->hnddma.rxnobuf++;
			break;
		}

		*(uint32*)(OSL_UNCACHED(PKTDATA(di->drv, p))) = 0;

		pa = (uint32) DMA_MAP(di->dev, PKTDATA(di->drv, p), rxbufsize, DMA_RX, p);
		ASSERT(ISALIGNED(pa, 4));

		/* save the free packet pointer */
		ASSERT(di->rxp[rxout] == NULL);
		di->rxp[rxout] = p;

		/* prep the descriptor control value */
		ctrl = rxbufsize;
		if (rxout == (di->nrxd - 1))
			ctrl |= CTRL_EOT;

		/* init the rx descriptor */
		W_SM(&di->rxd[rxout].ctrl, BUS_SWAP32(ctrl));
		W_SM(&di->rxd[rxout].addr, BUS_SWAP32(pa + di->dataoffset));

		rxout = NEXTRXD(rxout);
	}

	di->rxout = rxout;

	/* update the chip lastdscr pointer */
	W_REG(&di->regs->rcvptr, I2B(rxout));
}

void
dma_txreclaim(dma_info_t *di, bool forceall)
{
	void *p;

	DMA_TRACE(("%s: dma_txreclaim %s\n", di->name, forceall ? "all" : ""));

	while ((p = dma_getnexttxp(di, forceall)))
		PKTFREE(di->drv, p, TRUE);
}

/*
 * Reclaim next completed txd (txds if using chained buffers) and
 * return associated packet.
 * If 'force' is true, reclaim txd(s) and return associated packet
 * regardless of the value of the hardware "curr" pointer.
 */
void*
dma_getnexttxp(dma_info_t *di, bool forceall)
{
	uint start, end, i;
	void *txp;

	DMA_TRACE(("%s: dma_getnexttxp %s\n", di->name, forceall ? "all" : ""));

	txp = NULL;

	start = di->txin;
	if (forceall)
		end = di->txout;
	else
		end = B2I(R_REG(&di->regs->xmtstatus) & XS_CD_MASK);

	if ((start == 0) && (end > di->txout))
		goto bogus;

	for (i = start; i != end && !txp; i = NEXTTXD(i)) {
		DMA_UNMAP(di->dev, (BUS_SWAP32(R_SM(&di->txd[i].addr)) - di->dataoffset),
			  (BUS_SWAP32(R_SM(&di->txd[i].ctrl)) & CTRL_BC_MASK), DMA_TX, di->txp[i]);
		W_SM(&di->txd[i].addr, 0xdeadbeef);
		txp = di->txp[i];
		di->txp[i] = NULL;
	}

	di->txin = i;

	/* tx flow control */
	di->txavail = di->ntxd - NTXDACTIVE(di->txin, di->txout) - 1;

	return (txp);

bogus:
/*
	DMA_ERROR(("dma_getnexttxp: bogus curr: start %d end %d txout %d force %d\n",
		start, end, di->txout, forceall));
*/
	return (NULL);
}

/* like getnexttxp but no reclaim */
void*
dma_peeknexttxp(dma_info_t *di)
{
	uint end, i;

	end = B2I(R_REG(&di->regs->xmtstatus) & XS_CD_MASK);

	for (i = di->txin; i != end; i = NEXTTXD(i))
		if (di->txp[i])
			return (di->txp[i]);

	return (NULL);
}

void
dma_rxreclaim(dma_info_t *di)
{
	void *p;

	DMA_TRACE(("%s: dma_rxreclaim\n", di->name));

	while ((p = dma_getnextrxp(di, TRUE)))
		PKTFREE(di->drv, p, FALSE);
}

void *
dma_getnextrxp(dma_info_t *di, bool forceall)
{
	uint i;
	void *rxp;

	/* if forcing, dma engine must be disabled */
	ASSERT(!forceall || !dma_rxenabled(di));

	i = di->rxin;

	/* return if no packets posted */
	if (i == di->rxout)
		return (NULL);

	/* ignore curr if forceall */
	if (!forceall && (i == B2I(R_REG(&di->regs->rcvstatus) & RS_CD_MASK)))
		return (NULL);

	/* get the packet pointer that corresponds to the rx descriptor */
	rxp = di->rxp[i];
	ASSERT(rxp);
	di->rxp[i] = NULL;

	/* clear this packet from the descriptor ring */
	DMA_UNMAP(di->dev, (BUS_SWAP32(R_SM(&di->rxd[i].addr)) - di->dataoffset),
		  di->rxbufsize, DMA_RX, rxp);
	W_SM(&di->rxd[i].addr, 0xdeadbeef);

	di->rxin = NEXTRXD(i);

	return (rxp);
}

char*
dma_dumptx(dma_info_t *di, char *buf)
{
	buf += sprintf(buf, "txd 0x%lx txdpa 0x%lx txp 0x%lx txin %d txout %d txavail %d\n",
		(ulong)di->txd, di->txdpa, (ulong)di->txp, di->txin, di->txout, di->txavail);
	buf += sprintf(buf, "xmtcontrol 0x%x xmtaddr 0x%x xmtptr 0x%x xmtstatus 0x%x\n",
		R_REG(&di->regs->xmtcontrol),
		R_REG(&di->regs->xmtaddr),
		R_REG(&di->regs->xmtptr),
		R_REG(&di->regs->xmtstatus));
	return (buf);
}

char*
dma_dumprx(dma_info_t *di, char *buf)
{
	buf += sprintf(buf, "rxd 0x%lx rxdpa 0x%lx rxp 0x%lx rxin %d rxout %d\n",
		(ulong)di->rxd, di->rxdpa, (ulong)di->rxp, di->rxin, di->rxout);
	buf += sprintf(buf, "rcvcontrol 0x%x rcvaddr 0x%x rcvptr 0x%x rcvstatus 0x%x\n",
		R_REG(&di->regs->rcvcontrol),
		R_REG(&di->regs->rcvaddr),
		R_REG(&di->regs->rcvptr),
		R_REG(&di->regs->rcvstatus));
	return (buf);
}

char*
dma_dump(dma_info_t *di, char *buf)
{
	buf = dma_dumptx(di, buf);
	buf = dma_dumprx(di, buf);
	return (buf);
}

uint
dma_getvar(dma_info_t *di, char *name)
{
	if (!strcmp(name, "&txavail"))
		return ((uint) &di->txavail);
	else {
		ASSERT(0);
	}
	return (0);
}

void
dma_txblock(dma_info_t *di)
{
	di->txavail = 0;
}

void
dma_txunblock(dma_info_t *di)
{
	di->txavail = di->ntxd - NTXDACTIVE(di->txin, di->txout) - 1;
}

uint
dma_txactive(dma_info_t *di)
{
	return (NTXDACTIVE(di->txin, di->txout));
}

/*
 * Rotate all active tx dma ring entries "forward" by (ActiveDescriptor - txin).
 */
void
dma_txrotate(di_t *di)
{
	uint ad;
	uint nactive;
	uint rot;
	uint old, new;
	uint32 w;
	uint first, last;

	ASSERT(dma_txsuspended(di));

	nactive = dma_txactive(di);
	ad = B2I((R_REG(&di->regs->xmtstatus) & XS_AD_MASK) >> XS_AD_SHIFT);
	rot = TXD(ad - di->txin);

	ASSERT(rot < di->ntxd);

	/* full-ring case is a lot harder - don't worry about this */
	if (rot >= (di->ntxd - nactive)) {
		DMA_ERROR(("%s: dma_txrotate: ring full - punt\n", di->name));
		return;
	}

	first = di->txin;
	last = PREVTXD(di->txout);

	/* move entries starting at last and moving backwards to first */
	for (old = last; old != PREVTXD(first); old = PREVTXD(old)) {
		new = TXD(old + rot);

		/*
		 * Move the tx dma descriptor.
		 * EOT is set only in the last entry in the ring.
		 */
		w = R_SM(&di->txd[old].ctrl) & ~CTRL_EOT;
		if (new == (di->ntxd - 1))
			w |= CTRL_EOT;
		W_SM(&di->txd[new].ctrl, w);
		W_SM(&di->txd[new].addr, R_SM(&di->txd[old].addr));

		/* zap the old tx dma descriptor address field */
		W_SM(&di->txd[old].addr, 0xdeadbeef);

		/* move the corresponding txp[] entry */
		ASSERT(di->txp[new] == NULL);
		di->txp[new] = di->txp[old];
		di->txp[old] = NULL;
	}

	/* update txin and txout */
	di->txin = ad;
	di->txout = TXD(di->txout + rot);
	di->txavail = di->ntxd - NTXDACTIVE(di->txin, di->txout) - 1;

	/* kick the chip */
	W_REG(&di->regs->xmtptr, I2B(di->txout));
}