skge.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

		ReceiveIrq(pAC, &pAC->RxPort[pNet->PortNr], SK_TRUE);
		ClearRxRing(pAC, &pAC->RxPort[pNet->PortNr]);
		ClearTxRing(pAC, &pAC->TxPort[pNet->PortNr][TX_PRIO_LOW]);
	}

	SK_DBG_MSG(NULL, SK_DBGMOD_DRV, SK_DBGCAT_DRV_ENTRY,
		("SkGeClose: done "));

	pAC->MaxPorts--;
	pNet->Up = 0;
	MOD_DEC_USE_COUNT;
	
	return (0);
} /* SkGeClose */


/*****************************************************************************
 *
 * 	SkGeXmit - Linux frame transmit function
 *
 * Description:
 *	The system calls this function to send frames onto the wire.
 *	It puts the frame in the tx descriptor ring. If the ring is
 *	full then, the 'tbusy' flag is set.
 *
 * Returns:
 *	0, if everything is ok
 *	!=0, on error
 * WARNING: returning 1 in 'tbusy' case caused system crashes (double
 *	allocated skb's) !!!
 */
static int SkGeXmit(struct sk_buff *skb, struct SK_NET_DEVICE *dev)
{
DEV_NET		*pNet;
SK_AC		*pAC;
int			Rc;	/* return code of XmitFrame */

	pNet = (DEV_NET*) dev->priv;
	pAC = pNet->pAC;

	if ((!skb_shinfo(skb)->nr_frags) || 
		(pAC->GIni.GIChipId == CHIP_ID_GENESIS)) {
		/* Don't activate scatter-gather and hardware checksum */

		if (pAC->RlmtNets == 2)
			Rc = XmitFrame(
				pAC,
				&pAC->TxPort[pNet->PortNr][TX_PRIO_LOW],
				skb);
		else
			Rc = XmitFrame(
				pAC,
				&pAC->TxPort[pAC->ActivePort][TX_PRIO_LOW],
				skb);
	} else {
		/* scatter-gather and hardware TCP checksumming anabled*/
		if (pAC->RlmtNets == 2)
			Rc = XmitFrameSG(
				pAC,
				&pAC->TxPort[pNet->PortNr][TX_PRIO_LOW],
				skb);
		else
			Rc = XmitFrameSG(
				pAC,
				&pAC->TxPort[pAC->ActivePort][TX_PRIO_LOW],
				skb);
	}

	/* Transmitter out of resources? */
	if (Rc <= 0) {
		netif_stop_queue(dev);
	}

	/* If not taken, give buffer ownership back to the
	 * queueing layer.
	 */
	if (Rc < 0)
		return (1);

	dev->trans_start = jiffies;
	return (0);
} /* SkGeXmit */


/*****************************************************************************
 *
 * 	XmitFrame - fill one socket buffer into the transmit ring
 *
 * Description:
 *	This function puts a message into the transmit descriptor ring
 *	if there is a descriptors left.
 *	Linux skb's consist of only one continuous buffer.
 *	The first step locks the ring. It is held locked
 *	all time to avoid problems with SWITCH_../PORT_RESET.
 *	Then the descriptoris allocated.
 *	The second part is linking the buffer to the descriptor.
 *	At the very last, the Control field of the descriptor
 *	is made valid for the BMU and a start TX command is given
 *	if necessary.
 *
 * Returns:
 *	> 0 - on succes: the number of bytes in the message
 *	= 0 - on resource shortage: this frame sent or dropped, now
 *		the ring is full ( -> set tbusy)
 *	< 0 - on failure: other problems ( -> return failure to upper layers)
 */
static int XmitFrame(
SK_AC 		*pAC,		/* pointer to adapter context */
TX_PORT		*pTxPort,	/* pointer to struct of port to send to */
struct sk_buff	*pMessage)	/* pointer to send-message */
{
TXD		*pTxd;		/* the rxd to fill */
unsigned long	Flags;
SK_U64		PhysAddr;
int		BytesSend;

	SK_DBG_MSG(NULL, SK_DBGMOD_DRV, SK_DBGCAT_DRV_TX_PROGRESS,
		("X"));

	spin_lock_irqsave(&pTxPort->TxDesRingLock, Flags);
#ifndef USE_TX_COMPLETE
	FreeTxDescriptors(pAC, pTxPort);
#endif
	if (pTxPort->TxdRingFree == 0) {
		/* no enough free descriptors in ring at the moment */
		FreeTxDescriptors(pAC, pTxPort);
		if (pTxPort->TxdRingFree == 0) {
			spin_unlock_irqrestore(&pTxPort->TxDesRingLock, Flags);
			SK_PNMI_CNT_NO_TX_BUF(pAC, pTxPort->PortIndex);
			SK_DBG_MSG(NULL, SK_DBGMOD_DRV,
				SK_DBGCAT_DRV_TX_PROGRESS,
				("XmitFrame failed\n"));
			/* this message can not be sent now */
			/* Because tbusy seems to be set, the message should not be freed here */
			/* It will be used by the scheduler of the ethernet handler */
			return (-1);
		}
	}
	/* advance head counter behind descriptor needed for this frame */
	pTxd = pTxPort->pTxdRingHead;
	pTxPort->pTxdRingHead = pTxd->pNextTxd;
	pTxPort->TxdRingFree--;
	/* the needed descriptor is reserved now */
	
	/* 
	 * everything allocated ok, so add buffer to descriptor
	 */

#ifdef SK_DUMP_TX
	DumpMsg(pMessage, "XmitFrame");
#endif

	/* set up descriptor and CONTROL dword */
	PhysAddr = (SK_U64) pci_map_page(pAC->PciDev,
		virt_to_page(pMessage->data),
		((unsigned long) pMessage->data &
		~PAGE_MASK),
		pMessage->len,
		PCI_DMA_TODEVICE);
	pTxd->VDataLow = (SK_U32)  (PhysAddr & 0xffffffff);
	pTxd->VDataHigh = (SK_U32) (PhysAddr >> 32);
	pTxd->pMBuf = pMessage;
	pTxd->TBControl = TX_CTRL_OWN_BMU | TX_CTRL_STF |
		TX_CTRL_CHECK_DEFAULT | TX_CTRL_SOFTWARE |
#ifdef USE_TX_COMPLETE
		TX_CTRL_EOF | TX_CTRL_EOF_IRQ | pMessage->len;
#else
		TX_CTRL_EOF | pMessage->len;
#endif
	
	if ((pTxPort->pTxdRingPrev->TBControl & TX_CTRL_OWN_BMU) == 0) {
		/* previous descriptor already done, so give tx start cmd */
		/* StartTx(pAC, pTxPort->HwAddr); */
		SK_OUT8(pTxPort->HwAddr, TX_Q_CTRL, TX_Q_CTRL_START);
	}
	pTxPort->pTxdRingPrev = pTxd;
	
	
	BytesSend = pMessage->len;
	spin_unlock_irqrestore(&pTxPort->TxDesRingLock, Flags);
	/* after releasing the lock, the skb may be immidiately freed */
	if (pTxPort->TxdRingFree != 0)
		return (BytesSend);
	else
		return (0);

} /* XmitFrame */

/*****************************************************************************
 *
 * 	XmitFrameSG - fill one socket buffer into the transmit ring
 *                (use SG and TCP/UDP hardware checksumming)
 *
 * Description:
 *	This function puts a message into the transmit descriptor ring
 *	if there is a descriptors left.
 *
 * Returns:
 *	> 0 - on succes: the number of bytes in the message
 *	= 0 - on resource shortage: this frame sent or dropped, now
 *		the ring is full ( -> set tbusy)
 *	< 0 - on failure: other problems ( -> return failure to upper layers)
 */
static int XmitFrameSG(
SK_AC 		*pAC,			/* pointer to adapter context */
TX_PORT		*pTxPort,		/* pointer to struct of port to send to */
struct sk_buff	*pMessage)	/* pointer to send-message */
{

	int 		i;
	int			BytesSend;
	int			hlength;
	int			protocol;
	skb_frag_t		*sk_frag;
	TXD			*pTxd;
	TXD			*pTxdFst;
	TXD			*pTxdLst;
	SK_U64		PhysAddr;
	unsigned long	Flags;

	spin_lock_irqsave(&pTxPort->TxDesRingLock, Flags);
#ifndef USE_TX_COMPLETE
	FreeTxDescriptors(pAC, pTxPort);
#endif
	if ((skb_shinfo(pMessage)->nr_frags +1) > pTxPort->TxdRingFree) {
		FreeTxDescriptors(pAC, pTxPort);
		if ((skb_shinfo(pMessage)->nr_frags + 1) > pTxPort->TxdRingFree) {
			spin_unlock_irqrestore(&pTxPort->TxDesRingLock, Flags);
			SK_PNMI_CNT_NO_TX_BUF(pAC, pTxPort->PortIndex);
			SK_DBG_MSG(NULL, SK_DBGMOD_DRV,
				SK_DBGCAT_DRV_TX_PROGRESS,
				("XmitFrameSG failed - Ring full\n"));
				/* this message can not be sent now */
			return(-1);
		}
	}


	pTxd = pTxPort->pTxdRingHead;
	pTxdFst = pTxd;
	pTxdLst = pTxd;
	BytesSend = 0;
	protocol = 0;

	/* map first fragment (header) */
	PhysAddr = (SK_U64) pci_map_page(pAC->PciDev,
			virt_to_page(pMessage->data),
			((unsigned long) pMessage->data & ~PAGE_MASK),
			skb_headlen(pMessage),
			PCI_DMA_TODEVICE);

	pTxd->VDataLow = (SK_U32)  (PhysAddr & 0xffffffff);
	pTxd->VDataHigh = (SK_U32) (PhysAddr >> 32);

	/* HW checksum? */
	if (pMessage->ip_summed == CHECKSUM_HW) {
		pTxd->TBControl = TX_CTRL_STF |
				  TX_CTRL_ST_FWD |
				  skb_headlen(pMessage);

		/* We have to use the opcode for tcp here because the opcode for
		udp is not working in the hardware yet (revision 2.0)*/
		protocol = ((SK_U8)pMessage->data[23] & 0xf);
		if ((protocol == 17) && (pAC->GIni.GIChipRev != 0))
			pTxd->TBControl |=  BMU_UDP_CHECK;
		else
			pTxd->TBControl |= BMU_TCP_CHECK ;

		hlength = ((SK_U8)pMessage->data[14] & 0xf) * 4;
		pTxd->TcpSumOfs = 0; /* PH-Checksum already claculated */
		pTxd->TcpSumSt = 14+hlength+16;
		pTxd->TcpSumWr = 14+hlength;
	
	} else {
		pTxd->TBControl = TX_CTRL_CHECK_DEFAULT | 
				  TX_CTRL_SOFTWARE |
				  TX_CTRL_STF |
				  skb_headlen(pMessage);
	}

	pTxd = pTxd->pNextTxd;
	pTxPort->TxdRingFree--;
	BytesSend += skb_headlen(pMessage);


	/* Map SG fragments */
	for (i = 0; i < skb_shinfo(pMessage)->nr_frags; i++) {
		sk_frag = &skb_shinfo(pMessage)->frags[i];
		
		/* we already have the proper value in entry */
		PhysAddr = (SK_U64) pci_map_page(pAC->PciDev,
						 sk_frag->page,
						 sk_frag->page_offset,
						 sk_frag->size,
						 PCI_DMA_TODEVICE);

		pTxd->VDataLow = (SK_U32)  (PhysAddr & 0xffffffff);
		pTxd->VDataHigh = (SK_U32) (PhysAddr >> 32);
		pTxd->pMBuf = pMessage;
		
		/* HW checksum */
		if (pMessage->ip_summed == CHECKSUM_HW) {
			pTxd->TBControl = TX_CTRL_OWN_BMU | 
				  	  TX_CTRL_SOFTWARE |
					  TX_CTRL_ST_FWD;

			/* We have to use the opcode for tcp here because the opcode for
			udp is not working in the hardware yet (revision 2.0)*/
			if ((protocol == 17) && (pAC->GIni.GIChipRev != 0))
				pTxd->TBControl |= BMU_UDP_CHECK ;
			else
				pTxd->TBControl |= BMU_TCP_CHECK ;

		} else {
			pTxd->TBControl = TX_CTRL_CHECK_DEFAULT |
					  TX_CTRL_SOFTWARE |
					  TX_CTRL_OWN_BMU;
		}

		/* Last fragment  */
		if( (i+1) == skb_shinfo(pMessage)->nr_frags )  {
#ifdef USE_TX_COMPLETE
			pTxd->TBControl |= TX_CTRL_EOF |
					   TX_CTRL_EOF_IRQ |
					   sk_frag->size;
#else
			pTxd->TBControl |= TX_CTRL_EOF |
					   sk_frag->size;
#endif
			pTxdFst->TBControl |= TX_CTRL_OWN_BMU |
					      TX_CTRL_SOFTWARE; 

		} else {
			pTxd->TBControl |= sk_frag->size;
		}
		pTxdLst = pTxd;
		pTxd = pTxd->pNextTxd;
		pTxPort->TxdRingFree--;
		BytesSend += sk_frag->size;
	}

	if ((pTxPort->pTxdRingPrev->TBControl & TX_CTRL_OWN_BMU) == 0) {
		/* previous descriptor already done, so give tx start cmd */
		/* StartTx(pAC, pTxPort->HwAddr); */
		SK_OUT8(pTxPort->HwAddr, TX_Q_CTRL, TX_Q_CTRL_START);
	}

	pTxPort->pTxdRingPrev = pTxdLst;
	pTxPort->pTxdRingHead = pTxd;

	spin_unlock_irqrestore(&pTxPort->TxDesRingLock, Flags);

	if (pTxPort->TxdRingFree > 0)
		return (BytesSend);
	else
		return (0);
}


void dump_frag( SK_U8 *data, int length)
{
        int i;

        printk("Length: %d\n", length);                
        for( i=0; i < length; i++ ) {
                printk(" %02x", (SK_U8)*(data + i) );
                if( !((i+1) % 20) )
                  printk("\n");
        }
        printk("\n\n");

}


/*****************************************************************************
 *
 * 	FreeTxDescriptors - release descriptors from the descriptor ring
 *
 * Description:
 *	This function releases descriptors from a transmit ring if they
 *	have been sent by the BMU.
 *	If a descriptors is sent, it can be freed and the message can
 *	be freed, too.
 *	The SOFTWARE controllable bit is used to prevent running around a
 *	completely free ring for ever. If this bit is no set in the
 *	frame (by XmitFrame), this frame has never been sent or is
 *	already freed.
 *	The Tx descriptor ring lock must be held while calling this function !!!
 *
 * Returns:
 *	none
 */
static void FreeTxDescriptors(
SK_AC	*pAC,		/* pointer to the adapter context */
TX_PORT	*pTxPort)	/* pointer to destination port structure */
{
TXD	*pTxd;		/* pointer to the checked descriptor */
TXD	*pNewTail;	/* pointer to 'end' of the ring */
SK_U32	Control;	/* TBControl field of descriptor */
SK_U64	PhysAddr;	/* address of DMA mapping */

	pNewTail = pTxPort->pTxdRingTail;
	pTxd = pNewTail;
	/* 
	 * loop forever; exits if TX_CTRL_SOFTWARE bit not set in start frame
	 * or TX_CTRL_OWN_BMU bit set in any frame
	 */
	while (1) {
		Control = pTxd->TBControl;
		if ((Control & TX_CTRL_SOFTWARE) == 0) {
			/* 
			 * software controllable bit is set in first
			 * fragment when given to BMU. Not set means that
			 * this fragment was never sent or is already 
			 * freed ( -> ring completely free now).
			 */
			pTxPort->pTxdRingTail = pTxd;
			netif_start_queue(pAC->dev[pTxPort->PortIndex]);
			return;
		}
		if (Control & TX_CTRL_OWN_BMU) {
			pTxPort->pTxdRingTail = pTxd;
			if (pTxPort->TxdRingFree > 0) {
				netif_start_queue(pAC->dev[pTxPort->PortIndex]);
			}
			return;
		}
		
		/* release the DMA mapping */
		PhysAddr = ((SK_U64) pTxd->VDataHigh) << (SK_U64) 32;
		PhysAddr |= (SK_U64) pTxd->VDataLow;
		pci_unmap_page(pAC->PciDev, PhysAddr,
				 pTxd->pMBuf->len,
				 PCI_DMA_TODEVICE);

		if (Control & TX_CTRL_EOF)
			DEV_KFREE_SKB_ANY(pTxd->pMBuf);	/* free message */

		pTxPort->TxdRingFree++;
		pTxd->TBControl &= ~TX_CTRL_SOFTWARE;
		pTxd = pTxd->pNextTxd; /* point behind fragment with EOF */
	} /* while(forever) */
} /* FreeTxDescriptors */

/*****************************************************************************
 *
 * 	FillRxRing - fill the receive ring with valid descriptors
 *
 * Description:
 *	This function fills the receive ring descriptors with data
 *	segments and makes them valid for the BMU.
 *	The active ring is filled completely, if possible.
 *	The non-active ring is filled only partial to save memory.
 *
 * Description of rx ring structure:
 *	head - points to the descriptor which will be used next