i810_dma.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

/* i810_dma.c -- DMA support for the i810 -*- linux-c -*-
 * Created: Mon Dec 13 01:50:01 1999 by [e-mail]
 *
 * 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.
 *
 * Authors: Rickard E. (Rik) Faith <[e-mail]>
 *	    Jeff Hartmann <[e-mail]>
 *          Keith Whitwell <[e-mail]>
 *
 */

#include <linux/config.h>
#include "i810.h"
#include "drmP.h"
#include "drm.h"
#include "i810_drm.h"
#include "i810_drv.h"
#include <linux/interrupt.h>	/* For task queue support */
#include <linux/delay.h>

#define DO_MUNMAP(m, a, l)	do_munmap(m, a, l)

#define I810_BUF_FREE		2
#define I810_BUF_CLIENT		1
#define I810_BUF_HARDWARE      	0

#define I810_BUF_UNMAPPED 0
#define I810_BUF_MAPPED   1

#define RING_LOCALS	unsigned int outring, ringmask; volatile char *virt;

#define BEGIN_LP_RING(n) do {						\
	if (0) DRM_DEBUG("BEGIN_LP_RING(%d) in %s\n", n, __FUNCTION__);	\
	if (dev_priv->ring.space < n*4)					\
		i810_wait_ring(dev, n*4);				\
	dev_priv->ring.space -= n*4;					\
	outring = dev_priv->ring.tail;					\
	ringmask = dev_priv->ring.tail_mask;				\
	virt = dev_priv->ring.virtual_start;				\
} while (0)

#define ADVANCE_LP_RING() do {				\
	if (0) DRM_DEBUG("ADVANCE_LP_RING\n");			\
	dev_priv->ring.tail = outring;			\
	I810_WRITE(LP_RING + RING_TAIL, outring);	\
} while(0)

#define OUT_RING(n) do {				\
	if (0) DRM_DEBUG("   OUT_RING %x\n", (int)(n));	\
	*(volatile unsigned int *)(virt + outring) = n;	\
	outring += 4;					\
	outring &= ringmask;				\
} while (0)

static inline void i810_print_status_page(drm_device_t *dev)
{
   	drm_device_dma_t *dma = dev->dma;
      	drm_i810_private_t *dev_priv = dev->dev_private;
	u32 *temp = (u32 *)dev_priv->hw_status_page;
   	int i;

   	DRM_DEBUG(  "hw_status: Interrupt Status : %x\n", temp[0]);
   	DRM_DEBUG(  "hw_status: LpRing Head ptr : %x\n", temp[1]);
   	DRM_DEBUG(  "hw_status: IRing Head ptr : %x\n", temp[2]);
      	DRM_DEBUG(  "hw_status: Reserved : %x\n", temp[3]);
	DRM_DEBUG(  "hw_status: Last Render: %x\n", temp[4]);
   	DRM_DEBUG(  "hw_status: Driver Counter : %d\n", temp[5]);
   	for(i = 6; i < dma->buf_count + 6; i++) {
	   	DRM_DEBUG( "buffer status idx : %d used: %d\n", i - 6, temp[i]);
	}
}

static drm_buf_t *i810_freelist_get(drm_device_t *dev)
{
   	drm_device_dma_t *dma = dev->dma;
	int		 i;
   	int 		 used;

	/* Linear search might not be the best solution */

   	for (i = 0; i < dma->buf_count; i++) {
	   	drm_buf_t *buf = dma->buflist[ i ];
	   	drm_i810_buf_priv_t *buf_priv = buf->dev_private;
		/* In use is already a pointer */
	   	used = cmpxchg(buf_priv->in_use, I810_BUF_FREE,
			       I810_BUF_CLIENT);
	   	if(used == I810_BUF_FREE) {
			return buf;
		}
	}
   	return NULL;
}

/* This should only be called if the buffer is not sent to the hardware
 * yet, the hardware updates in use for us once its on the ring buffer.
 */

static int i810_freelist_put(drm_device_t *dev, drm_buf_t *buf)
{
   	drm_i810_buf_priv_t *buf_priv = buf->dev_private;
   	int used;

   	/* In use is already a pointer */
   	used = cmpxchg(buf_priv->in_use, I810_BUF_CLIENT, I810_BUF_FREE);
   	if(used != I810_BUF_CLIENT) {
	   	DRM_ERROR("Freeing buffer thats not in use : %d\n", buf->idx);
	   	return -EINVAL;
	}

   	return 0;
}

static struct file_operations i810_buffer_fops = {
	.open	 = DRM(open),
	.flush	 = DRM(flush),
	.release = DRM(release),
	.ioctl	 = DRM(ioctl),
	.mmap	 = i810_mmap_buffers,
	.read	 = DRM(read),
	.fasync  = DRM(fasync),
      	.poll	 = DRM(poll),
};

int i810_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
{
	drm_file_t	    *priv	  = filp->private_data;
	drm_device_t	    *dev;
	drm_i810_private_t  *dev_priv;
	drm_buf_t           *buf;
	drm_i810_buf_priv_t *buf_priv;

	lock_kernel();
	dev	 = priv->dev;
	dev_priv = dev->dev_private;
	buf      = dev_priv->mmap_buffer;
	buf_priv = buf->dev_private;

	vma->vm_flags |= (VM_IO | VM_DONTCOPY);
	vma->vm_file = filp;

   	buf_priv->currently_mapped = I810_BUF_MAPPED;
	unlock_kernel();

	if (remap_page_range(DRM_RPR_ARG(vma) vma->vm_start,
			     VM_OFFSET(vma),
			     vma->vm_end - vma->vm_start,
			     vma->vm_page_prot)) return -EAGAIN;
	return 0;
}

static int i810_map_buffer(drm_buf_t *buf, struct file *filp)
{
	drm_file_t	  *priv	  = filp->private_data;
	drm_device_t	  *dev	  = priv->dev;
	drm_i810_buf_priv_t *buf_priv = buf->dev_private;
      	drm_i810_private_t *dev_priv = dev->dev_private;
   	struct file_operations *old_fops;
	int retcode = 0;

	if(buf_priv->currently_mapped == I810_BUF_MAPPED) return -EINVAL;




	down_write( &current->mm->mmap_sem );

	old_fops = filp->f_op;
	filp->f_op = &i810_buffer_fops;
	dev_priv->mmap_buffer = buf;
	buf_priv->virtual = (void *)do_mmap(filp, 0, buf->total,
					    PROT_READ|PROT_WRITE,
					    MAP_SHARED,
					    buf->bus_address);
	dev_priv->mmap_buffer = NULL;
	filp->f_op = old_fops;
	if ((unsigned long)buf_priv->virtual > -1024UL) {
		/* Real error */
		DRM_DEBUG("mmap error\n");
		retcode = (signed int)buf_priv->virtual;
		buf_priv->virtual = 0;
	}



	up_write( &current->mm->mmap_sem );

	return retcode;
}

static int i810_unmap_buffer(drm_buf_t *buf)
{
	drm_i810_buf_priv_t *buf_priv = buf->dev_private;
	int retcode = 0;

	if(buf_priv->currently_mapped != I810_BUF_MAPPED)
		return -EINVAL;



	down_write( &current->mm->mmap_sem );

	retcode = DO_MUNMAP(current->mm,
			    (unsigned long)buf_priv->virtual,
			    (size_t) buf->total);



	up_write( &current->mm->mmap_sem );

   	buf_priv->currently_mapped = I810_BUF_UNMAPPED;
   	buf_priv->virtual = 0;

	return retcode;
}

static int i810_dma_get_buffer(drm_device_t *dev, drm_i810_dma_t *d,
			       struct file *filp)
{
	drm_file_t	  *priv	  = filp->private_data;
	drm_buf_t	  *buf;
	drm_i810_buf_priv_t *buf_priv;
	int retcode = 0;

	buf = i810_freelist_get(dev);
	if (!buf) {
		retcode = -ENOMEM;
	   	DRM_DEBUG("retcode=%d\n", retcode);
		return retcode;
	}

	retcode = i810_map_buffer(buf, filp);
	if(retcode) {
		i810_freelist_put(dev, buf);
	   	DRM_DEBUG("mapbuf failed, retcode %d\n", retcode);
		return retcode;
	}
	buf->pid     = priv->pid;
	buf_priv = buf->dev_private;
	d->granted = 1;
   	d->request_idx = buf->idx;
   	d->request_size = buf->total;
   	d->virtual = buf_priv->virtual;

	return retcode;
}

static int i810_dma_cleanup(drm_device_t *dev)
{
	drm_device_dma_t *dma = dev->dma;

	if(dev->dev_private) {
		int i;
	   	drm_i810_private_t *dev_priv =
	     		(drm_i810_private_t *) dev->dev_private;

	   	if(dev_priv->ring.virtual_start) {
		   	DRM(ioremapfree)((void *) dev_priv->ring.virtual_start,
					 dev_priv->ring.Size);
		}
	   	if(dev_priv->hw_status_page != 0UL) {
		   	pci_free_consistent(dev->pdev, PAGE_SIZE,
					    (void *)dev_priv->hw_status_page,
					    dev_priv->dma_status_page);
		   	/* Need to rewrite hardware status page */
		   	I810_WRITE(0x02080, 0x1ffff000);
		}
	   	DRM(free)(dev->dev_private, sizeof(drm_i810_private_t),
			 DRM_MEM_DRIVER);
	   	dev->dev_private = NULL;

		for (i = 0; i < dma->buf_count; i++) {
			drm_buf_t *buf = dma->buflist[ i ];
			drm_i810_buf_priv_t *buf_priv = buf->dev_private;
			DRM(ioremapfree)(buf_priv->kernel_virtual, buf->total);
		}
	}
   	return 0;
}

static int i810_wait_ring(drm_device_t *dev, int n)
{
   	drm_i810_private_t *dev_priv = dev->dev_private;
   	drm_i810_ring_buffer_t *ring = &(dev_priv->ring);
   	int iters = 0;
   	unsigned long end;
	unsigned int last_head = I810_READ(LP_RING + RING_HEAD) & HEAD_ADDR;

	end = jiffies + (HZ*3);
   	while (ring->space < n) {
	   	ring->head = I810_READ(LP_RING + RING_HEAD) & HEAD_ADDR;
	   	ring->space = ring->head - (ring->tail+8);
		if (ring->space < 0) ring->space += ring->Size;

		if (ring->head != last_head)
		   end = jiffies + (HZ*3);

	   	iters++;
		if(time_before(end, jiffies)) {
		   	DRM_ERROR("space: %d wanted %d\n", ring->space, n);
		   	DRM_ERROR("lockup\n");
		   	goto out_wait_ring;
		}
	   	udelay(1);
	}

out_wait_ring:
   	return iters;
}

static void i810_kernel_lost_context(drm_device_t *dev)
{
      	drm_i810_private_t *dev_priv = dev->dev_private;
   	drm_i810_ring_buffer_t *ring = &(dev_priv->ring);

   	ring->head = I810_READ(LP_RING + RING_HEAD) & HEAD_ADDR;
     	ring->tail = I810_READ(LP_RING + RING_TAIL);
     	ring->space = ring->head - (ring->tail+8);
     	if (ring->space < 0) ring->space += ring->Size;
}

static int i810_freelist_init(drm_device_t *dev, drm_i810_private_t *dev_priv)
{
      	drm_device_dma_t *dma = dev->dma;
   	int my_idx = 24;
   	u32 *hw_status = (u32 *)(dev_priv->hw_status_page + my_idx);
   	int i;

   	if(dma->buf_count > 1019) {
	   	/* Not enough space in the status page for the freelist */
	   	return -EINVAL;
	}

   	for (i = 0; i < dma->buf_count; i++) {
	   	drm_buf_t *buf = dma->buflist[ i ];
	   	drm_i810_buf_priv_t *buf_priv = buf->dev_private;

	   	buf_priv->in_use = hw_status++;
	   	buf_priv->my_use_idx = my_idx;
	   	my_idx += 4;

	   	*buf_priv->in_use = I810_BUF_FREE;

		buf_priv->kernel_virtual = DRM(ioremap)(buf->bus_address,
							buf->total);
	}
	return 0;
}

static int i810_dma_initialize(drm_device_t *dev,
			       drm_i810_private_t *dev_priv,
			       drm_i810_init_t *init)
{
	struct list_head *list;

   	memset(dev_priv, 0, sizeof(drm_i810_private_t));

	list_for_each(list, &dev->maplist->head) {
		drm_map_list_t *r_list = (drm_map_list_t *)list;
		if( r_list->map &&
		    r_list->map->type == _DRM_SHM &&
		    r_list->map->flags & _DRM_CONTAINS_LOCK ) {
			dev_priv->sarea_map = r_list->map;
 			break;
 		}
 	}
	if(!dev_priv->sarea_map) {
		dev->dev_private = (void *)dev_priv;
	   	i810_dma_cleanup(dev);
	   	DRM_ERROR("can not find sarea!\n");
	   	return -EINVAL;
	}
	DRM_FIND_MAP( dev_priv->mmio_map, init->mmio_offset );
	if(!dev_priv->mmio_map) {
		dev->dev_private = (void *)dev_priv;
	   	i810_dma_cleanup(dev);
	   	DRM_ERROR("can not find mmio map!\n");
	   	return -EINVAL;
	}
	DRM_FIND_MAP( dev_priv->buffer_map, init->buffers_offset );
	if(!dev_priv->buffer_map) {
		dev->dev_private = (void *)dev_priv;
	   	i810_dma_cleanup(dev);
	   	DRM_ERROR("can not find dma buffer map!\n");
	   	return -EINVAL;
	}

	dev_priv->sarea_priv = (drm_i810_sarea_t *)
		((u8 *)dev_priv->sarea_map->handle +
		 init->sarea_priv_offset);

   	dev_priv->ring.Start = init->ring_start;
   	dev_priv->ring.End = init->ring_end;
   	dev_priv->ring.Size = init->ring_size;

   	dev_priv->ring.virtual_start = DRM(ioremap)(dev->agp->base +
						    init->ring_start,
						    init->ring_size);