//-------------------------------------------------------------------
//	syncfix.c		Addition of driver 'flush()' method
//
//	Here is the addition of a 'flush()' function for our RealTek
//	character-mode device-driver versions previously posted, and
//	an accompanying modification to the interrupt-handler in the
//	case of a transmit-error.  An 'fsync()' function also may be 
//	added with no extra effort, because it's based on 'flush()'.  		
//
//	programmer: ALLAN CRUSE
//	written on: 02 MAY 2005
//	revised on: 04 MAY 2005 -- removes 'bug' found by Jean Bovet
//-------------------------------------------------------------------

#include <linux/module.h>	// for init_module() 
#include <linux/wait.h>		// for init_waitqueue_head()
#include <linux/pci.h>		// for inb(), outb()
#include <linux/interrupt.h>	// for request_irq(), free_irq()
#include <linux/fs.h>		// for kill_fasync()

int iobase, irq;		// assigned adapter resources
wait_queue_head_t tx_wq;	// queue for sleeping writers


int my_flush( struct file *file )
{
	// Normally this function should only return when the device
	// has been completely flushed -- i.e., when all the packets 
	// that had been queued for transmission have been sent out.
	// (For this, the RealTek's TSAD register can be consulted.)

	int	port = iobase + 0x60;	// TSAD register port-address

	int	tsad = inw( port );			   // Temporary
	printk( "Executing flush (tsad=%04X) \n", tsad );  // Temporary

	// interrupt-handler (below) will now retransmit if TxErr==1
	//wait_event_interruptible( tx_wq, inw( port ) == 0xF00F ); <--- bug!
	wait_event_interruptible( tx_wq, (inw( port )&0xF) == 0xF ); 

	tsad = inw( port );				   // Temporary
	printk( "Verifying flush (tsad=%04X) \n", tsad );  // Temporary
	return	0;
}

int my_fsync( struct file *file, struct dentry *dentry, int datasync )
{
	my_flush( file );
	return	0;
}

struct file_operations my_fops = {
				owner:		THIS_MODULE,
				flush:		my_flush,	// <-- ADDED
				fsync:		my_fsync,	// <-- ADDED
				};


irqreturn_t my_isr( int irq, void *dev_id, struct pt_regs *regs )
{
        int     intstatus = inw( iobase + 0x3E );
        if ( intstatus == 0 ) return IRQ_NONE;  // it wasn't for us

	// ..... include below changes in interrupt-handler .....

        if ( intstatus & 0x04 )  // packet was transmitted OK
                wake_up_interruptible( &tx_wq ); // wake up any writers

        if ( intstatus & 0x08 )  // packet had transmission error
                {
                printk( "Transmit error! \n" );	// Temporary message
                // ok, retransmit the packet (see RealTek manual)
                outl( inl( iobase + 0x40 )|1, iobase + 0x40 );
                }
	// ......................................................

        outw( intstatus, iobase + 0x3E );       // clear the interrupts
        return  IRQ_HANDLED;                    // resume current task
}