#include <u.h>
#include <libc.h>

#include "reg.h"
#include "ring.h"

int
ringinit(Ring *r, u32int *mmio, void *va, uintptr gtta)
{
	int i;
	u32int *rp;

	r->mmio = mmio;
	r->va = va;
	r->gtta = gtta;

	rp = r->va;

	for(i = 0; i < 128; i++)
		*rp++ = MI_NOOP_ID(i);

	rp = r->va;

	/* 2d processor - XY_COLOR_BLT - rgb channel - 4 dwords */
	*rp++ = (2<<29) | (0x50<<22) | (1<<20) | 4;
	/* 32bpp - copy - pitch */
	*rp++ = (3<<24) | (0xF0<<16) | 1440*4;

	/* Y1 - X1 */
	*rp++ = (10 << 16) | 10;
	/* Y2 - X2 */
	*rp++ = (100 << 16) | 100;

	/* base address */
	*rp++ = 0;

	/* pattern - red */
	*rp++ = 0x00FF0000;

	return 0;
}

/* c.f. init_ring_common */
int
ringstart(Ring *r)
{
	int i;

	werrstr("");
	if(!ringstop(r)){
		fprint(2, "ring: first stop failed: %r\n");
		if(!ringstop(r)){
			fprint(2, "ring: second stop failed: %r\n");
			return -1;
		}
	}

	USED(r->mmio[RING_BUFFER_HEAD/4]);

	/* XXX: ordering seems to matter here */
	r->mmio[RING_BUFFER_START/4] = r->gtta;

	if(r->mmio[RING_BUFFER_HEAD/4])
		fprint(2, "ring: head nonzero %08ux\n", r->mmio[RING_BUFFER_HEAD/4]);

	r->mmio[RING_BUFFER_HEAD/4] = 0;
	r->mmio[RING_BUFFER_TAIL/4] = 128*4;

	USED(r->mmio[RING_BUFFER_TAIL/4]);

	/* 20:12 contain # of pages, 0 meaning 1 4k page */
	r->mmio[RING_BUFFER_CTL/4] = 1;

	for(i = 0; i < 50; i++){
		if(r->mmio[RING_BUFFER_CTL/4] & 1)
			break;
		sleep(1);
	}

	if(i == 50){
		fprint(2, "ring: timed out waiting for ring to be valid\n");
		return -1;
	}

	/* enable parser/ring arbitration */
	r->mmio[MI_MODE/4] = (MI_MODE_STOP << 16) | 0;

	return 0;
}

int
ringstop(Ring *r)
{
	int i;
	u32int reg;

	/* force ring/cp idle */
	r->mmio[MI_MODE/4] = (MI_MODE_STOP << 16) | MI_MODE_STOP;

	for(i = 0; i < 1000; i++){
		reg = r->mmio[MI_MODE/4];

		if(reg & MI_MODE_IDLE)
			break;

		sleep(1);
	}

	if(i == 1000){
		werrstr("ring: timed out trying to stop ring");
		return -1;
	}

	r->mmio[RING_BUFFER_HEAD/4] = r->mmio[RING_BUFFER_TAIL/4];

	r->mmio[RING_BUFFER_HEAD/4] = 0;
	r->mmio[RING_BUFFER_TAIL/4] = 0;
	r->mmio[RING_BUFFER_CTL/4] = 0;

	return (r->mmio[RING_BUFFER_HEAD/4] & 0x1FFFFC) == 0;
}

int
ringbusy(Ring *r)
{
	return r->mmio[RING_BUFFER_HEAD/4] != r->mmio[RING_BUFFER_TAIL/4];
}