#include <sys/param.h>
#include <sys/systm.h>
#include <sys/file.h>
#include <sys/buf.h>
#include <sys/syslog.h>
#include <sys/malloc.h>
#include <sys/uio.h>

#include <vm/vm.h>

#include <machine/pio.h>

#include <i386/isa/isareg.h>
#include <i386/isa/dmavar.h>
#include <i386/isa/dmareg.h>

/* region of physical memory known to be contiguous */
vm_offset_t isaphysmem;
static caddr_t dma_bounce[8];		/* XXX */
static char bounced[8];		/* XXX */
#define MAXDMASZ 512		/* XXX */

/* high byte of address is stored in this port for i-th dma channel */
static short dmapageport[8] =
	{ 0x87, 0x83, 0x81, 0x82, 0x8f, 0x8b, 0x89, 0x8a };

/*
 * isa_dmacascade(): program 8237 DMA controller channel to accept
 * external dma control by a board.
 */
void
isa_dmacascade(chan)
	int chan;
{

#ifdef DIAGNOSTIC
	if (chan < 0 || chan > 7)
		panic("isa_dmacascade: impossible request"); 
#endif

	/* set dma channel mode, and set dma channel mode */
	if ((chan & 4) == 0) {
		outb(DMA1_MODE, DMA37MD_CASCADE | chan);
		outb(DMA1_SMSK, chan);
	} else {
		outb(DMA2_MODE, DMA37MD_CASCADE | (chan & 3));
		outb(DMA2_SMSK, chan & 3);
	}
}

/*
 * isa_dmastart(): program 8237 DMA controller channel, avoid page alignment
 * problems by using a bounce buffer.
 */
void
isa_dmastart(flags, addr, nbytes, chan)
	int flags;
	caddr_t addr;
	vm_size_t nbytes;
	int chan;
{
	vm_offset_t phys;
	int waport;
	caddr_t newaddr;

#ifdef DIAGNOSTIC
	if (chan < 0 || chan > 7 ||
	    ((chan & 4) ? (nbytes >= (1<<17) || nbytes & 1 || (u_int)addr & 1) :
	    (nbytes >= (1<<16))))
		panic("isa_dmastart: impossible request"); 
#endif

	if (isa_dmarangecheck(addr, nbytes, chan)) {
		if (dma_bounce[chan] == 0)
			dma_bounce[chan] =
			    /*(caddr_t)malloc(MAXDMASZ, M_TEMP, M_WAITOK);*/
			    (caddr_t) isaphysmem + NBPG*chan;
		bounced[chan] = 1;
		newaddr = dma_bounce[chan];
		*(int *) newaddr = 0;	/* XXX */
		/* copy bounce buffer on write */
		if ((flags & B_READ) == 0)
			bcopy(addr, newaddr, nbytes);
		addr = newaddr;
	}

	/* translate to physical */
	phys = pmap_extract(kernel_pmap, (vm_offset_t)addr);

	if ((chan & 4) == 0) {
		/*
		 * Program one of DMA channels 0..3.  These are
		 * byte mode channels.
		 */
		/* set dma channel mode, and reset address ff */
		if (flags & B_READ)
			outb(DMA1_MODE, chan | DMA37MD_SINGLE | DMA37MD_WRITE);
		else
			outb(DMA1_MODE, chan | DMA37MD_SINGLE | DMA37MD_READ);
		outb(DMA1_FFC, 0);

		/* send start address */
		waport =  DMA1_CHN(chan);
		outb(waport, phys);
		outb(waport, phys>>8);
		outb(dmapageport[chan], phys>>16);

		/* send count */
		outb(waport + 1, --nbytes);
		outb(waport + 1, nbytes>>8);

		/* unmask channel */
		outb(DMA1_SMSK, chan | DMA37SM_CLEAR);
	} else {
		/*
		 * Program one of DMA channels 4..7.  These are
		 * word mode channels.
		 */
		/* set dma channel mode, and reset address ff */
		if (flags & B_READ)
			outb(DMA2_MODE, (chan & 3) | DMA37MD_SINGLE | DMA37MD_WRITE);
		else
			outb(DMA2_MODE, (chan & 3) | DMA37MD_SINGLE | DMA37MD_READ);
		outb(DMA2_FFC, 0);

		/* send start address */
		waport = DMA2_CHN(chan & 3);
		outb(waport, phys>>1);
		outb(waport, phys>>9);
		outb(dmapageport[chan], phys>>16);

		/* send count */
		nbytes >>= 1;
		outb(waport + 2, --nbytes);
		outb(waport + 2, nbytes>>8);

		/* unmask channel */
		outb(DMA2_SMSK, (chan & 3) | DMA37SM_CLEAR);
	}
}

void
isa_dmaabort(chan)
	int chan;
{

#ifdef DIAGNOSTIC
	if (chan < 0 || chan > 7)
		panic("isa_dmaabort: impossible request");
#endif

	bounced[chan] = 0;

	/* mask channel */
	if ((chan & 4) == 0)
		outb(DMA1_SMSK, DMA37SM_SET | chan);
	else
		outb(DMA2_SMSK, DMA37SM_SET | (chan & 3));
}

void
isa_dmadone(flags, addr, nbytes, chan)
	int flags;
	caddr_t addr;
	vm_size_t nbytes;
	int chan;
{
	u_char tc;

#ifdef DIAGNOSTIC
	if (chan < 0 || chan > 7)
		panic("isa_dmadone: impossible request");
#endif

	/* check that the terminal count was reached */
	if ((chan & 4) == 0)
		tc = inb(DMA1_SR) & (1 << chan);
	else
		tc = inb(DMA2_SR) & (1 << (chan & 3));
	if (tc == 0)
		/* XXX probably should panic or something */
		log(LOG_ERR, "dma channel %d not finished\n", chan);

	/* copy bounce buffer on read */
	if (bounced[chan]) {
		bcopy(dma_bounce[chan], addr, nbytes);
		bounced[chan] = 0;
	}

	/* mask channel */
	if ((chan & 4) == 0)
		outb(DMA1_SMSK, DMA37SM_SET | chan);
	else
		outb(DMA2_SMSK, DMA37SM_SET | (chan & 3));
}

/*
 * Check for problems with the address range of a DMA transfer
 * (non-contiguous physical pages, outside of bus address space,
 * crossing DMA page boundaries).
 * Return true if special handling needed.
 */
int
isa_dmarangecheck(va, length, chan)
	vm_offset_t va;
	u_long length;
	int chan;
{
	vm_offset_t phys, priorpage = 0, endva;
	u_int dma_pgmsk = (chan & 4) ?  ~(128*1024-1) : ~(64*1024-1);

	endva = round_page(va + length);
	for (; va < endva ; va += NBPG) {
		phys = trunc_page(pmap_extract(kernel_pmap, va));
		if (phys == 0)
			panic("isa_dmacheck: no physical page present");
		if (phys >= (1<<24)) 
			return 1;
		if (priorpage) {
			if (priorpage + NBPG != phys)
				return 1;
			/* check if crossing a DMA page boundary */
			if ((priorpage ^ phys) & dma_pgmsk)
				return 1;
		}
		priorpage = phys;
	}
	return 0;
}

/* head of queue waiting for physmem to become available */
struct buf isa_physmemq;

/* blocked waiting for resource to become free for exclusive use */
static isaphysmemflag;
/* if waited for and call requested when free (B_CALL) */
static void (*isaphysmemunblock)(); /* needs to be a list */

/*
 * Allocate contiguous physical memory for transfer, returning
 * a *virtual* address to region. May block waiting for resource.
 * (assumed to be called at splbio())
 */
caddr_t
isa_allocphysmem(caddr_t va, unsigned length, void (*func)()) {
	
	isaphysmemunblock = func;
	while (isaphysmemflag & B_BUSY) {
		isaphysmemflag |= B_WANTED;
		sleep((caddr_t)&isaphysmemflag, PRIBIO);
	}
	isaphysmemflag |= B_BUSY;

	return((caddr_t)isaphysmem);
}

/*
 * Free contiguous physical memory used for transfer.
 * (assumed to be called at splbio())
 */
void
isa_freephysmem(caddr_t va, unsigned length) {

	isaphysmemflag &= ~B_BUSY;
	if (isaphysmemflag & B_WANTED) {
		isaphysmemflag &= B_WANTED;
		wakeup((caddr_t)&isaphysmemflag);
		if (isaphysmemunblock)
			(*isaphysmemunblock)();
	}
}