i2lib.c

linux-2.6.15.6

/*******************************************************************************
*
*   (c) 1999 by Computone Corporation
*
********************************************************************************
*
*
*   PACKAGE:     Linux tty Device Driver for IntelliPort family of multiport
*                serial I/O controllers.
*
*   DESCRIPTION: High-level interface code for the device driver. Uses the
*                Extremely Low Level Interface Support (i2ellis.c). Provides an
*                interface to the standard loadware, to support drivers or
*                application code. (This is included source code, not a separate
*                compilation module.)
*
*******************************************************************************/
//------------------------------------------------------------------------------
// Note on Strategy:
// Once the board has been initialized, it will interrupt us when:
// 1) It has something in the fifo for us to read (incoming data, flow control
// packets, or whatever).
// 2) It has stripped whatever we have sent last time in the FIFO (and
// consequently is ready for more).
//
// Note also that the buffer sizes declared in i2lib.h are VERY SMALL. This
// worsens performance considerably, but is done so that a great many channels
// might use only a little memory.
//------------------------------------------------------------------------------

//------------------------------------------------------------------------------
// Revision History:
//
// 0.00 -  4/16/91 --- First Draft
// 0.01 -  4/29/91 --- 1st beta release
// 0.02 -  6/14/91 --- Changes to allow small model compilation
// 0.03 -  6/17/91 MAG Break reporting protected from interrupts routines with
//                     in-line asm added for moving data to/from ring buffers,
//                     replacing a variety of methods used previously.
// 0.04 -  6/21/91 MAG Initial flow-control packets not queued until
//                     i2_enable_interrupts time. Former versions would enqueue
//                     them at i2_init_channel time, before we knew how many
//                     channels were supposed to exist!
// 0.05 - 10/12/91 MAG Major changes: works through the ellis.c routines now;
//                     supports new 16-bit protocol and expandable boards.
//      - 10/24/91 MAG Most changes in place and stable.
// 0.06 -  2/20/92 MAG Format of CMD_HOTACK corrected: the command takes no
//                     argument.
// 0.07 -- 3/11/92 MAG Support added to store special packet types at interrupt
//                     level (mostly responses to specific commands.)
// 0.08 -- 3/30/92 MAG Support added for STAT_MODEM packet
// 0.09 -- 6/24/93 MAG i2Link... needed to update number of boards BEFORE
//                     turning on the interrupt.
// 0.10 -- 6/25/93 MAG To avoid gruesome death from a bad board, we sanity check
//                     some incoming.
//
// 1.1  - 12/25/96 AKM Linux version.
//      - 10/09/98 DMC Revised Linux version.
//------------------------------------------------------------------------------

//************
//* Includes *
//************

#include <linux/sched.h>
#include "i2lib.h"


//***********************
//* Function Prototypes *
//***********************
static void i2QueueNeeds(i2eBordStrPtr, i2ChanStrPtr, int);
static i2ChanStrPtr i2DeQueueNeeds(i2eBordStrPtr, int );
static void i2StripFifo(i2eBordStrPtr);
static void i2StuffFifoBypass(i2eBordStrPtr);
static void i2StuffFifoFlow(i2eBordStrPtr);
static void i2StuffFifoInline(i2eBordStrPtr);
static int i2RetryFlushOutput(i2ChanStrPtr);

// Not a documented part of the library routines (careful...) but the Diagnostic
// i2diag.c finds them useful to help the throughput in certain limited
// single-threaded operations.
static void iiSendPendingMail(i2eBordStrPtr);
static void serviceOutgoingFifo(i2eBordStrPtr);

// Functions defined in ip2.c as part of interrupt handling
static void do_input(void *);
static void do_status(void *);

//***************
//* Debug  Data *
//***************
#ifdef DEBUG_FIFO

unsigned char DBGBuf[0x4000];
unsigned short I = 0;

static void
WriteDBGBuf(char *s, unsigned char *src, unsigned short n ) 
{
	char *p = src;

	// XXX: We need a spin lock here if we ever use this again

	while (*s) {	// copy label
		DBGBuf[I] = *s++;
		I = I++ & 0x3fff;
	}
	while (n--) {	// copy data
		DBGBuf[I] = *p++;
		I = I++ & 0x3fff;
	}
}

static void
fatality(i2eBordStrPtr pB )
{
	int i;

	for (i=0;i<sizeof(DBGBuf);i++) {
		if ((i%16) == 0)
			printk("\n%4x:",i);
		printk("%02x ",DBGBuf[i]);
	}
	printk("\n");
	for (i=0;i<sizeof(DBGBuf);i++) {
		if ((i%16) == 0)
			printk("\n%4x:",i);
		if (DBGBuf[i] >= ' ' && DBGBuf[i] <= '~') {
			printk(" %c ",DBGBuf[i]);
		} else {
			printk(" . ");
		}
	}
	printk("\n");
	printk("Last index %x\n",I);
}
#endif /* DEBUG_FIFO */

//********
//* Code *
//********

static inline int
i2Validate ( i2ChanStrPtr pCh )
{
	//ip2trace(pCh->port_index, ITRC_VERIFY,ITRC_ENTER,2,pCh->validity,
	//	(CHANNEL_MAGIC | CHANNEL_SUPPORT));
	return ((pCh->validity & (CHANNEL_MAGIC_BITS | CHANNEL_SUPPORT)) 
			  == (CHANNEL_MAGIC | CHANNEL_SUPPORT));
}

//******************************************************************************
// Function:   iiSendPendingMail(pB)
// Parameters: Pointer to a board structure
// Returns:    Nothing
//
// Description:
// If any outgoing mail bits are set and there is outgoing mailbox is empty,
// send the mail and clear the bits.
//******************************************************************************
static inline void
iiSendPendingMail(i2eBordStrPtr pB)
{
	if (pB->i2eOutMailWaiting && (!pB->i2eWaitingForEmptyFifo) )
	{
		if (iiTrySendMail(pB, pB->i2eOutMailWaiting))
		{
			/* If we were already waiting for fifo to empty,
			 * or just sent MB_OUT_STUFFED, then we are
			 * still waiting for it to empty, until we should
			 * receive an MB_IN_STRIPPED from the board.
			 */
			pB->i2eWaitingForEmptyFifo |=
				(pB->i2eOutMailWaiting & MB_OUT_STUFFED);
			pB->i2eOutMailWaiting = 0;
			pB->SendPendingRetry = 0;
		} else {
/*		The only time we hit this area is when "iiTrySendMail" has
		failed.  That only occurs when the outbound mailbox is
		still busy with the last message.  We take a short breather
		to let the board catch up with itself and then try again.
		16 Retries is the limit - then we got a borked board.
			/\/\|=mhw=|\/\/				*/

			if( ++pB->SendPendingRetry < 16 ) {

				init_timer( &(pB->SendPendingTimer) );
				pB->SendPendingTimer.expires  = jiffies + 1;
				pB->SendPendingTimer.function = (void*)(unsigned long)iiSendPendingMail;
				pB->SendPendingTimer.data     = (unsigned long)pB;
				add_timer( &(pB->SendPendingTimer) );
			} else {
				printk( KERN_ERR "IP2: iiSendPendingMail unable to queue outbound mail\n" );
			}
		}
	}
}

//******************************************************************************
// Function:   i2InitChannels(pB, nChannels, pCh)
// Parameters: Pointer to Ellis Board structure
//             Number of channels to initialize
//             Pointer to first element in an array of channel structures
// Returns:    Success or failure
//
// Description:
//
// This function patches pointers, back-pointers, and initializes all the
// elements in the channel structure array.
//
// This should be run after the board structure is initialized, through having
// loaded the standard loadware (otherwise it complains).
//
// In any case, it must be done before any serious work begins initializing the
// irq's or sending commands...
//
//******************************************************************************
static int
i2InitChannels ( i2eBordStrPtr pB, int nChannels, i2ChanStrPtr pCh)
{
	int index, stuffIndex;
	i2ChanStrPtr *ppCh;
	
	if (pB->i2eValid != I2E_MAGIC) {
		COMPLETE(pB, I2EE_BADMAGIC);
	}
	if (pB->i2eState != II_STATE_STDLOADED) {
		COMPLETE(pB, I2EE_BADSTATE);
	}

	LOCK_INIT(&pB->read_fifo_spinlock);
	LOCK_INIT(&pB->write_fifo_spinlock);
	LOCK_INIT(&pB->Dbuf_spinlock);
	LOCK_INIT(&pB->Bbuf_spinlock);
	LOCK_INIT(&pB->Fbuf_spinlock);
	
	// NO LOCK needed yet - this is init

	pB->i2eChannelPtr = pCh;
	pB->i2eChannelCnt = nChannels;

	pB->i2Fbuf_strip = pB->i2Fbuf_stuff = 0;
	pB->i2Dbuf_strip = pB->i2Dbuf_stuff = 0;
	pB->i2Bbuf_strip = pB->i2Bbuf_stuff = 0;

	pB->SendPendingRetry = 0;

	memset ( pCh, 0, sizeof (i2ChanStr) * nChannels );

	for (index = stuffIndex = 0, ppCh = (i2ChanStrPtr *)(pB->i2Fbuf);
		  nChannels && index < ABS_MOST_PORTS;
		  index++)
	{
		if ( !(pB->i2eChannelMap[index >> 4] & (1 << (index & 0xf)) ) ) {
			continue;
		}
		LOCK_INIT(&pCh->Ibuf_spinlock);
		LOCK_INIT(&pCh->Obuf_spinlock);
		LOCK_INIT(&pCh->Cbuf_spinlock);
		LOCK_INIT(&pCh->Pbuf_spinlock);
		// NO LOCK needed yet - this is init
		// Set up validity flag according to support level
		if (pB->i2eGoodMap[index >> 4] & (1 << (index & 0xf)) ) {
			pCh->validity = CHANNEL_MAGIC | CHANNEL_SUPPORT;
		} else {
			pCh->validity = CHANNEL_MAGIC;
		}
		pCh->pMyBord = pB;      /* Back-pointer */

		// Prepare an outgoing flow-control packet to send as soon as the chance
		// occurs.
		if ( pCh->validity & CHANNEL_SUPPORT ) {
			pCh->infl.hd.i2sChannel = index;
			pCh->infl.hd.i2sCount = 5;
			pCh->infl.hd.i2sType = PTYPE_BYPASS;
			pCh->infl.fcmd = 37;
			pCh->infl.asof = 0;
			pCh->infl.room = IBUF_SIZE - 1;

			pCh->whenSendFlow = (IBUF_SIZE/5)*4; // when 80% full

		// The following is similar to calling i2QueueNeeds, except that this
		// is done in longhand, since we are setting up initial conditions on
		// many channels at once.
			pCh->channelNeeds = NEED_FLOW;  // Since starting from scratch
			pCh->sinceLastFlow = 0;         // No bytes received since last flow
											// control packet was queued
			stuffIndex++;
			*ppCh++ = pCh;      // List this channel as needing
								// initial flow control packet sent
		}

		// Don't allow anything to be sent until the status packets come in from
		// the board.

		pCh->outfl.asof = 0;
		pCh->outfl.room = 0;

		// Initialize all the ring buffers

		pCh->Ibuf_stuff = pCh->Ibuf_strip = 0;
		pCh->Obuf_stuff = pCh->Obuf_strip = 0;
		pCh->Cbuf_stuff = pCh->Cbuf_strip = 0;

		memset( &pCh->icount, 0, sizeof (struct async_icount) );
		pCh->hotKeyIn       = HOT_CLEAR;
		pCh->channelOptions = 0;
		pCh->bookMarks      = 0;
		init_waitqueue_head(&pCh->pBookmarkWait);

		init_waitqueue_head(&pCh->open_wait);
		init_waitqueue_head(&pCh->close_wait);
		init_waitqueue_head(&pCh->delta_msr_wait);

		// Set base and divisor so default custom rate is 9600
		pCh->BaudBase    = 921600;	// MAX for ST654, changed after we get
		pCh->BaudDivisor = 96;		// the boxids (UART types) later

		pCh->dataSetIn   = 0;
		pCh->dataSetOut  = 0;

		pCh->wopen       = 0;
		pCh->throttled   = 0;

		pCh->speed       = CBR_9600;

		pCh->flags    = 0;

		pCh->ClosingDelay     = 5*HZ/10;
		pCh->ClosingWaitTime  = 30*HZ;

		// Initialize task queue objects
		INIT_WORK(&pCh->tqueue_input, do_input, pCh);
		INIT_WORK(&pCh->tqueue_status, do_status, pCh);

#ifdef IP2DEBUG_TRACE
		pCh->trace = ip2trace;
#endif

		++pCh;
     	--nChannels;
	}
	// No need to check for wrap here; this is initialization.
	pB->i2Fbuf_stuff = stuffIndex;
	COMPLETE(pB, I2EE_GOOD);

}

//******************************************************************************
// Function:   i2DeQueueNeeds(pB, type)
// Parameters: Pointer to a board structure
//             type bit map: may include NEED_INLINE, NEED_BYPASS, or NEED_FLOW
// Returns:   
//             Pointer to a channel structure
//
// Description: Returns pointer struct of next channel that needs service of
//  the type specified. Otherwise returns a NULL reference.
//
//******************************************************************************
static i2ChanStrPtr 
i2DeQueueNeeds(i2eBordStrPtr pB, int type)
{
	unsigned short queueIndex;
	unsigned long flags;

	i2ChanStrPtr pCh = NULL;

	switch(type) {

	case  NEED_INLINE:

		WRITE_LOCK_IRQSAVE(&pB->Dbuf_spinlock,flags);
		if ( pB->i2Dbuf_stuff != pB->i2Dbuf_strip)
		{
			queueIndex = pB->i2Dbuf_strip;
			pCh = pB->i2Dbuf[queueIndex];
			queueIndex++;
			if (queueIndex >= CH_QUEUE_SIZE) {
				queueIndex = 0;
			}
			pB->i2Dbuf_strip = queueIndex;
			pCh->channelNeeds &= ~NEED_INLINE;
		}
		WRITE_UNLOCK_IRQRESTORE(&pB->Dbuf_spinlock,flags); 
		break;

	case NEED_BYPASS:

		WRITE_LOCK_IRQSAVE(&pB->Bbuf_spinlock,flags);
		if (pB->i2Bbuf_stuff != pB->i2Bbuf_strip)
		{
			queueIndex = pB->i2Bbuf_strip;
			pCh = pB->i2Bbuf[queueIndex];
			queueIndex++;
			if (queueIndex >= CH_QUEUE_SIZE) {
				queueIndex = 0;
			}
			pB->i2Bbuf_strip = queueIndex;
			pCh->channelNeeds &= ~NEED_BYPASS;
		}
		WRITE_UNLOCK_IRQRESTORE(&pB->Bbuf_spinlock,flags); 
		break;
	
	case NEED_FLOW:

		WRITE_LOCK_IRQSAVE(&pB->Fbuf_spinlock,flags);
		if (pB->i2Fbuf_stuff != pB->i2Fbuf_strip)
		{
			queueIndex = pB->i2Fbuf_strip;
			pCh = pB->i2Fbuf[queueIndex];
			queueIndex++;
			if (queueIndex >= CH_QUEUE_SIZE) {
				queueIndex = 0;
			}
			pB->i2Fbuf_strip = queueIndex;
			pCh->channelNeeds &= ~NEED_FLOW;
		}
		WRITE_UNLOCK_IRQRESTORE(&pB->Fbuf_spinlock,flags); 
		break;
	default:
		printk(KERN_ERR "i2DeQueueNeeds called with bad type:%x\n",type);
		break;
	}
	return pCh;
}

//******************************************************************************
// Function:   i2QueueNeeds(pB, pCh, type)
// Parameters: Pointer to a board structure
//             Pointer to a channel structure
//             type bit map: may include NEED_INLINE, NEED_BYPASS, or NEED_FLOW
// Returns:    Nothing
//
// Description:
// For each type of need selected, if the given channel is not already in the
// queue, adds it, and sets the flag indicating it is in the queue.
//******************************************************************************