#include "types.h"
#include "dma.h"

ushort mask_port[]  = {0x0A, 0x0A, 0x0A, 0x0A, 0xD4, 0xD4, 0xD4, 0xD4};
ushort mode_port[]  = {0x0B, 0x0B, 0x0B, 0x0B, 0xD6, 0xD6, 0xD6, 0xD6};
ushort clear_port[] = {0x0C, 0x0C, 0x0C, 0x0C, 0xD8, 0xD8, 0xD8, 0xD8};
ushort page_port[]  = {0x87, 0x83, 0x81, 0x82, 0x8F, 0x8B, 0x89, 0x8A};
ushort addr_port[]  = {0x00, 0x02, 0x04, 0x06, 0xC0, 0xC4, 0xC8, 0xCC};
ushort count_port[] = {0x01, 0x03, 0x05, 0x07, 0xC2, 0xC6, 0xCA, 0xCE};

void dma_start(uchar channel, struct dma_block_t *block, uchar mode) {
	mode |= (channel % 4);

	outportb(mask_port[channel], channel | DMA_SET_MASK_BIT);

	outportb(clear_port[channel], 0x00);

	outportb(mode_port[channel], mode);
	
	// FIXME outportw would work, no?
	outportb(addr_port[channel], block->offset & 0xFF);
	outportb(addr_port[channel], (block->offset >> 8) & 0xFF);

	outportb(page_port[channel], block->page);
	
	uint len = block->len - 1;
	outportb(count_port[channel], len & 0xFF);
	outportb(count_port[channel], (len >> 8) & 0xFF);

	outportb(mask_port[channel], channel | DMA_CLEAR_MASK_BIT);
}

void dma_pause(uchar channel) {
	outportb(mask_port[channel], channel | DMA_SET_MASK_BIT);
}

void dma_unpause(uchar channel) {
	outportb(mask_port[channel], channel | DMA_CLEAR_MASK_BIT);
}

void dma_stop(uchar channel) {	
	outportb(mask_port[channel], channel | DMA_SET_MASK_BIT);

	outportb(clear_port[channel], 0x00);

	outportb(mask_port[channel], channel | DMA_CLEAR_MASK_BIT);
}