path: root/drivers/char/drm/mga_dma.c

/* mga_dma.c -- DMA support for mga g200/g400 -*- linux-c -*-
 * Created: Mon Dec 13 01:50:01 1999 by jhartmann@precisioninsight.com
 *
 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

/**
 * \file mga_dma.c
 * DMA support for MGA G200 / G400.
 * 
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Jeff Hartmann <jhartmann@valinux.com>
 * \author Keith Whitwell <keith@tungstengraphics.com>
 * \author Gareth Hughes <gareth@valinux.com>
 */

#include "drmP.h"
#include "drm.h"
#include "drm_sarea.h"
#include "mga_drm.h"
#include "mga_drv.h"

#define MGA_DEFAULT_USEC_TIMEOUT	10000
#define MGA_FREELIST_DEBUG		0

static int mga_do_cleanup_dma( drm_device_t *dev );

/* ================================================================
 * Engine control
 */

int mga_do_wait_for_idle( drm_mga_private_t *dev_priv )
{
	u32 status = 0;
	int i;
	DRM_DEBUG( "\n" );

	for ( i = 0 ; i < dev_priv->usec_timeout ; i++ ) {
		status = MGA_READ( MGA_STATUS ) & MGA_ENGINE_IDLE_MASK;
		if ( status == MGA_ENDPRDMASTS ) {
			MGA_WRITE8( MGA_CRTC_INDEX, 0 );
			return 0;
		}
		DRM_UDELAY( 1 );
	}

#if MGA_DMA_DEBUG
	DRM_ERROR( "failed!\n" );
	DRM_INFO( "   status=0x%08x\n", status );
#endif
	return DRM_ERR(EBUSY);
}

static int mga_do_dma_reset( drm_mga_private_t *dev_priv )
{
	drm_mga_sarea_t *sarea_priv = dev_priv->sarea_priv;
	drm_mga_primary_buffer_t *primary = &dev_priv->prim;

	DRM_DEBUG( "\n" );

	/* The primary DMA stream should look like new right about now.
	 */
	primary->tail = 0;
	primary->space = primary->size;
	primary->last_flush = 0;

	sarea_priv->last_wrap = 0;

	/* FIXME: Reset counters, buffer ages etc...
	 */

	/* FIXME: What else do we need to reinitialize?  WARP stuff?
	 */

	return 0;
}

/* ================================================================
 * Primary DMA stream
 */

void mga_do_dma_flush( drm_mga_private_t *dev_priv )
{
	drm_mga_primary_buffer_t *primary = &dev_priv->prim;
	u32 head, tail;
	u32 status = 0;
	int i;
 	DMA_LOCALS;
	DRM_DEBUG( "\n" );

        /* We need to wait so that we can do an safe flush */
	for ( i = 0 ; i < dev_priv->usec_timeout ; i++ ) {
		status = MGA_READ( MGA_STATUS ) & MGA_ENGINE_IDLE_MASK;
		if ( status == MGA_ENDPRDMASTS ) break;
		DRM_UDELAY( 1 );
	}

	if ( primary->tail == primary->last_flush ) {
		DRM_DEBUG( "   bailing out...\n" );
		return;
	}

	tail = primary->tail + dev_priv->primary->offset;

	/* We need to pad the stream between flushes, as the card
	 * actually (partially?) reads the first of these commands.
	 * See page 4-16 in the G400 manual, middle of the page or so.
	 */
	BEGIN_DMA( 1 );

	DMA_BLOCK( MGA_DMAPAD,  0x00000000,
		   MGA_DMAPAD,  0x00000000,
		   MGA_DMAPAD,  0x00000000,
		   MGA_DMAPAD,	0x00000000 );

	ADVANCE_DMA();

	primary->last_flush = primary->tail;

	head = MGA_READ( MGA_PRIMADDRESS );

	if ( head <