z85230.c

linux-2.6.15.6

	"Z85C30",
	"Z85230"
};

/**
 *	z8530_describe - Uniformly describe a Z8530 port
 *	@dev: Z8530 device to describe
 *	@mapping: string holding mapping type (eg "I/O" or "Mem")
 *	@io: the port value in question
 *
 *	Describe a Z8530 in a standard format. We must pass the I/O as
 *	the port offset isnt predictable. The main reason for this function
 *	is to try and get a common format of report.
 */

void z8530_describe(struct z8530_dev *dev, char *mapping, unsigned long io)
{
	printk(KERN_INFO "%s: %s found at %s 0x%lX, IRQ %d.\n",
		dev->name, 
		z8530_type_name[dev->type],
		mapping,
		Z8530_PORT_OF(io),
		dev->irq);
}

EXPORT_SYMBOL(z8530_describe);

/*
 *	Locked operation part of the z8530 init code
 */
 
static inline int do_z8530_init(struct z8530_dev *dev)
{
	/* NOP the interrupt handlers first - we might get a
	   floating IRQ transition when we reset the chip */
	dev->chanA.irqs=&z8530_nop;
	dev->chanB.irqs=&z8530_nop;
	dev->chanA.dcdcheck=DCD;
	dev->chanB.dcdcheck=DCD;

	/* Reset the chip */
	write_zsreg(&dev->chanA, R9, 0xC0);
	udelay(200);
	/* Now check its valid */
	write_zsreg(&dev->chanA, R12, 0xAA);
	if(read_zsreg(&dev->chanA, R12)!=0xAA)
		return -ENODEV;
	write_zsreg(&dev->chanA, R12, 0x55);
	if(read_zsreg(&dev->chanA, R12)!=0x55)
		return -ENODEV;
		
	dev->type=Z8530;
	
	/*
	 *	See the application note.
	 */
	 
	write_zsreg(&dev->chanA, R15, 0x01);
	
	/*
	 *	If we can set the low bit of R15 then
	 *	the chip is enhanced.
	 */
	 
	if(read_zsreg(&dev->chanA, R15)==0x01)
	{
		/* This C30 versus 230 detect is from Klaus Kudielka's dmascc */
		/* Put a char in the fifo */
		write_zsreg(&dev->chanA, R8, 0);
		if(read_zsreg(&dev->chanA, R0)&Tx_BUF_EMP)
			dev->type = Z85230;	/* Has a FIFO */
		else
			dev->type = Z85C30;	/* Z85C30, 1 byte FIFO */
	}
		
	/*
	 *	The code assumes R7' and friends are
	 *	off. Use write_zsext() for these and keep
	 *	this bit clear.
	 */
	 
	write_zsreg(&dev->chanA, R15, 0);
		
	/*
	 *	At this point it looks like the chip is behaving
	 */
	 
	memcpy(dev->chanA.regs, reg_init, 16);
	memcpy(dev->chanB.regs, reg_init ,16);
	
	return 0;
}

/**
 *	z8530_init - Initialise a Z8530 device
 *	@dev: Z8530 device to initialise.
 *
 *	Configure up a Z8530/Z85C30 or Z85230 chip. We check the device
 *	is present, identify the type and then program it to hopefully
 *	keep quite and behave. This matters a lot, a Z8530 in the wrong
 *	state will sometimes get into stupid modes generating 10Khz
 *	interrupt streams and the like.
 *
 *	We set the interrupt handler up to discard any events, in case
 *	we get them during reset or setp.
 *
 *	Return 0 for success, or a negative value indicating the problem
 *	in errno form.
 */

int z8530_init(struct z8530_dev *dev)
{
	unsigned long flags;
	int ret;

	/* Set up the chip level lock */
	spin_lock_init(&dev->lock);
	dev->chanA.lock = &dev->lock;
	dev->chanB.lock = &dev->lock;

	spin_lock_irqsave(&dev->lock, flags);
	ret = do_z8530_init(dev);
	spin_unlock_irqrestore(&dev->lock, flags);

	return ret;
}


EXPORT_SYMBOL(z8530_init);

/**
 *	z8530_shutdown - Shutdown a Z8530 device
 *	@dev: The Z8530 chip to shutdown
 *
 *	We set the interrupt handlers to silence any interrupts. We then 
 *	reset the chip and wait 100uS to be sure the reset completed. Just
 *	in case the caller then tries to do stuff.
 *
 *	This is called without the lock held
 */
 
int z8530_shutdown(struct z8530_dev *dev)
{
	unsigned long flags;
	/* Reset the chip */

	spin_lock_irqsave(&dev->lock, flags);
	dev->chanA.irqs=&z8530_nop;
	dev->chanB.irqs=&z8530_nop;
	write_zsreg(&dev->chanA, R9, 0xC0);
	/* We must lock the udelay, the chip is offlimits here */
	udelay(100);
	spin_unlock_irqrestore(&dev->lock, flags);
	return 0;
}

EXPORT_SYMBOL(z8530_shutdown);

/**
 *	z8530_channel_load - Load channel data
 *	@c: Z8530 channel to configure
 *	@rtable: table of register, value pairs
 *	FIXME: ioctl to allow user uploaded tables
 *
 *	Load a Z8530 channel up from the system data. We use +16 to 
 *	indicate the "prime" registers. The value 255 terminates the
 *	table.
 */

int z8530_channel_load(struct z8530_channel *c, u8 *rtable)
{
	unsigned long flags;

	spin_lock_irqsave(c->lock, flags);

	while(*rtable!=255)
	{
		int reg=*rtable++;
		if(reg>0x0F)
			write_zsreg(c, R15, c->regs[15]|1);
		write_zsreg(c, reg&0x0F, *rtable);
		if(reg>0x0F)
			write_zsreg(c, R15, c->regs[15]&~1);
		c->regs[reg]=*rtable++;
	}
	c->rx_function=z8530_null_rx;
	c->skb=NULL;
	c->tx_skb=NULL;
	c->tx_next_skb=NULL;
	c->mtu=1500;
	c->max=0;
	c->count=0;
	c->status=read_zsreg(c, R0);
	c->sync=1;
	write_zsreg(c, R3, c->regs[R3]|RxENABLE);

	spin_unlock_irqrestore(c->lock, flags);
	return 0;
}

EXPORT_SYMBOL(z8530_channel_load);


/**
 *	z8530_tx_begin - Begin packet transmission
 *	@c: The Z8530 channel to kick
 *
 *	This is the speed sensitive side of transmission. If we are called
 *	and no buffer is being transmitted we commence the next buffer. If
 *	nothing is queued we idle the sync. 
 *
 *	Note: We are handling this code path in the interrupt path, keep it
 *	fast or bad things will happen.
 *
 *	Called with the lock held.
 */

static void z8530_tx_begin(struct z8530_channel *c)
{
	unsigned long flags;
	if(c->tx_skb)
		return;
		
	c->tx_skb=c->tx_next_skb;
	c->tx_next_skb=NULL;
	c->tx_ptr=c->tx_next_ptr;
	
	if(c->tx_skb==NULL)
	{
		/* Idle on */
		if(c->dma_tx)
		{
			flags=claim_dma_lock();
			disable_dma(c->txdma);
			/*
			 *	Check if we crapped out.
			 */
			if(get_dma_residue(c->txdma))
			{
				c->stats.tx_dropped++;
				c->stats.tx_fifo_errors++;
			}
			release_dma_lock(flags);
		}
		c->txcount=0;
	}
	else
	{
		c->txcount=c->tx_skb->len;
		
		
		if(c->dma_tx)
		{
			/*
			 *	FIXME. DMA is broken for the original 8530,
			 *	on the older parts we need to set a flag and
			 *	wait for a further TX interrupt to fire this
			 *	stage off	
			 */
			 
			flags=claim_dma_lock();
			disable_dma(c->txdma);

			/*
			 *	These two are needed by the 8530/85C30
			 *	and must be issued when idling.
			 */
			 
			if(c->dev->type!=Z85230)
			{
				write_zsctrl(c, RES_Tx_CRC);
				write_zsctrl(c, RES_EOM_L);
			}	
			write_zsreg(c, R10, c->regs[10]&~ABUNDER);
			clear_dma_ff(c->txdma);
			set_dma_addr(c->txdma, virt_to_bus(c->tx_ptr));
			set_dma_count(c->txdma, c->txcount);
			enable_dma(c->txdma);
			release_dma_lock(flags);
			write_zsctrl(c, RES_EOM_L);
			write_zsreg(c, R5, c->regs[R5]|TxENAB);
		}
		else
		{

			/* ABUNDER off */
			write_zsreg(c, R10, c->regs[10]);
			write_zsctrl(c, RES_Tx_CRC);
	
			while(c->txcount && (read_zsreg(c,R0)&Tx_BUF_EMP))
			{		
				write_zsreg(c, R8, *c->tx_ptr++);
				c->txcount--;
			}

		}
	}
	/*
	 *	Since we emptied tx_skb we can ask for more
	 */
	netif_wake_queue(c->netdevice);
}

/**
 *	z8530_tx_done - TX complete callback
 *	@c: The channel that completed a transmit.
 *
 *	This is called when we complete a packet send. We wake the queue,
 *	start the next packet going and then free the buffer of the existing
 *	packet. This code is fairly timing sensitive.
 *
 *	Called with the register lock held.
 */ 
 
static void z8530_tx_done(struct z8530_channel *c)
{
	struct sk_buff *skb;

	/* Actually this can happen.*/
	if(c->tx_skb==NULL)
		return;

	skb=c->tx_skb;
	c->tx_skb=NULL;
	z8530_tx_begin(c);
	c->stats.tx_packets++;
	c->stats.tx_bytes+=skb->len;
	dev_kfree_skb_irq(skb);
}

/**
 *	z8530_null_rx - Discard a packet
 *	@c: The channel the packet arrived on
 *	@skb: The buffer
 *
 *	We point the receive handler at this function when idle. Instead
 *	of syncppp processing the frames we get to throw them away.
 */
 
void z8530_null_rx(struct z8530_channel *c, struct sk_buff *skb)
{
	dev_kfree_skb_any(skb);
}

EXPORT_SYMBOL(z8530_null_rx);

/**
 *	z8530_rx_done - Receive completion callback
 *	@c: The channel that completed a receive
 *
 *	A new packet is complete. Our goal here is to get back into receive
 *	mode as fast as possible. On the Z85230 we could change to using
 *	ESCC mode, but on the older chips we have no choice. We flip to the
 *	new buffer immediately in DMA mode so that the DMA of the next
 *	frame can occur while we are copying the previous buffer to an sk_buff
 *
 *	Called with the lock held
 */
 
static void z8530_rx_done(struct z8530_channel *c)
{
	struct sk_buff *skb;
	int ct;
	
	/*
	 *	Is our receive engine in DMA mode
	 */
	 
	if(c->rxdma_on)
	{
		/*
		 *	Save the ready state and the buffer currently
		 *	being used as the DMA target
		 */
		 
		int ready=c->dma_ready;
		unsigned char *rxb=c->rx_buf[c->dma_num];
		unsigned long flags;
		
		/*
		 *	Complete this DMA. Neccessary to find the length
		 */		
		 
		flags=claim_dma_lock();
		
		disable_dma(c->rxdma);
		clear_dma_ff(c->rxdma);
		c->rxdma_on=0;
		ct=c->mtu-get_dma_residue(c->rxdma);
		if(ct<0)
			ct=2;	/* Shit happens.. */
		c->dma_ready=0;
		
		/*
		 *	Normal case: the other slot is free, start the next DMA
		 *	into it immediately.
		 */
		 
		if(ready)
		{
			c->dma_num^=1;
			set_dma_mode(c->rxdma, DMA_MODE_READ|0x10);
			set_dma_addr(c->rxdma, virt_to_bus(c->rx_buf[c->dma_num]));
			set_dma_count(c->rxdma, c->mtu);
			c->rxdma_on = 1;
			enable_dma(c->rxdma);
			/* Stop any frames that we missed the head of 
			   from passing */
			write_zsreg(c, R0, RES_Rx_CRC);
		}
		else
			/* Can't occur as we dont reenable the DMA irq until
			   after the flip is done */
			printk(KERN_WARNING "%s: DMA flip overrun!\n", c->netdevice->name);
			
		release_dma_lock(flags);
		
		/*
		 *	Shove the old buffer into an sk_buff. We can't DMA
		 *	directly into one on a PC - it might be above the 16Mb
		 *	boundary. Optimisation - we could check to see if we
		 *	can avoid the copy. Optimisation 2 - make the memcpy
		 *	a copychecksum.
		 */
		 
		skb=dev_alloc_skb(ct);
		if(skb==NULL)
		{
			c->stats.rx_dropped++;
			printk(KERN_WARNING "%s: Memory squeeze.\n", c->netdevice->name);
		}
		else
		{
			skb_put(skb, ct);
			memcpy(skb->data, rxb, ct);
			c->stats.rx_packets++;
			c->stats.rx_bytes+=ct;
		}
		c->dma_ready=1;
	}
	else
	{
		RT_LOCK;	
		skb=c->skb;
		
		/*
		 *	The game we play for non DMA is similar. We want to
		 *	get the controller set up for the next packet as fast
		 *	as possible. We potentially only have one byte + the
		 *	fifo length for this. Thus we want to flip to the new
		 *	buffer and then mess around copying and allocating
		 *	things. For the current case it doesn't matter but
		 *	if you build a system where the sync irq isnt blocked
		 *	by the kernel IRQ disable then you need only block the
		 *	sync IRQ for the RT_LOCK area.
		 *	
		 */
		ct=c->count;
		
		c->skb = c->skb2;
		c->count = 0;
		c->max = c->mtu;
		if(c->skb)
		{
			c->dptr = c->skb->data;
			c->max = c->mtu;
		}
		else
		{
			c->count= 0;
			c->max = 0;
		}
		RT_UNLOCK;

		c->skb2 = dev_alloc_skb(c->mtu);
		if(c->skb2==NULL)
			printk(KERN_WARNING "%s: memory squeeze.\n",
				c->netdevice->name);
		else
		{
			skb_put(c->skb2,c->mtu);
		}
		c->stats.rx_packets++;
		c->stats.rx_bytes+=ct;
		
	}
	/*
	 *	If we received a frame we must now process it.
	 */
	if(skb)
	{
		skb_trim(skb, ct);
		c->rx_function(c,skb);
	}
	else
	{
		c->stats.rx_dropped++;
		printk(KERN_ERR "%s: Lost a frame\n", c->netdevice->name);
	}
}

/**
 *	spans_boundary - Check a packet can be ISA DMA'd
 *	@skb: The buffer to check
 *
 *	Returns true if the buffer cross a DMA boundary on a PC. The poor
 *	thing can only DMA within a 64K block not across the edges of it.
 */
 
static inline int spans_boundary(struct sk_buff *skb)
{
	unsigned long a=(unsigned long)skb->data;
	a^=(a+skb->len);
	if(a&0x00010000)	/* If the 64K bit is different.. */
		return 1;
	return 0;
}

/**
 *	z8530_queue_xmit - Queue a packet
 *	@c: The channel to use
 *	@skb: The packet to kick down the channel
 *
 *	Queue a packet for transmission. Because we have rather
 *	hard to hit interrupt latencies for the Z85230 per packet 
 *	even in DMA mode we do the flip to DMA buffer if needed here
 *	not in the IRQ.
 *
 *	Called from the network code. The lock is not held at this 
 *	point.
 */

int z8530_queue_xmit(struct z8530_channel *c, struct sk_buff *skb)
{
	unsigned long flags;
	
	netif_stop_queue(c->netdevice);
	if(c->tx_next_skb)
	{
		return 1;
	}
	
	/* PC SPECIFIC - DMA limits */
	
	/*
	 *	If we will DMA the transmit and its gone over the ISA bus
	 *	limit, then copy to the flip buffer
	 */
	 
	if(c->dma_tx && ((unsigned long)(virt_to_bus(skb->data+skb->len))>=16*1024*1024 || spans_boundary(skb)))
	{
		/* 
		 *	Send the flip buffer, and flip the flippy bit.
		 *	We don't care which is used when just so long as
		 *	we never use the same buffer twice in a row. Since
		 *	only one buffer can be going out at a time the other
		 *	has to be safe.
		 */
		c->tx_next_ptr=c->tx_dma_buf[c->tx_dma_used];
		c->tx_dma_used^=1;	/* Flip temp buffer */
		memcpy(c->tx_next_ptr, skb->data, skb->len);
	}
	else
		c->tx_next_ptr=skb->data;	
	RT_LOCK;
	c->tx_next_skb=skb;
	RT_UNLOCK;
	
	spin_lock_irqsave(c->lock, flags);
	z8530_tx_begin(c);
	spin_unlock_irqrestore(c->lock, flags);
	
	return 0;
}

EXPORT_SYMBOL(z8530_queue_xmit);

/**
 *	z8530_get_stats - Get network statistics
 *	@c: The channel to use
 *
 *	Get the statistics block. We keep the statistics in software as
 *	the chip doesn't do it for us.
 *
 *	Locking is ignored here - we could lock for a copy but its
 *	not likely to be that big an issue
 */
 
struct net_device_stats *z8530_get_stats(struct z8530_channel *c)
{
	return &c->stats;
}

EXPORT_SYMBOL(z8530_get_stats);

/*
 *	Module support
 */
static char banner[] __initdata = KERN_INFO "Generic Z85C30/Z85230 interface driver v0.02\n";

static int __init z85230_init_driver(void)
{
	printk(banner);
	return 0;
}
module_init(z85230_init_driver);

static void __exit z85230_cleanup_driver(void)
{
}
module_exit(z85230_cleanup_driver);

MODULE_AUTHOR("Red Hat Inc.");
MODULE_DESCRIPTION("Z85x30 synchronous driver core");
MODULE_LICENSE("GPL");