path: root/drivers/gpu/drm/i830/i830_dma.c

/* i830_dma.c -- DMA support for the I830 -*- 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.
 *
 * Authors: Rickard E. (Rik) Faith <faith@valinux.com>
 *	    Jeff Hartmann <jhartmann@valinux.com>
 *	    Keith Whitwell <keith@tungstengraphics.com>
 *	    Abraham vd Merwe <abraham@2d3d.co.za>
 *
 */

#include "drmP.h"
#include "drm.h"
#include "i830_drm.h"
#include "i830_drv.h"
#include <linux/interrupt.h>	/* For task queue support */
#include <linux/smp_lock.h>
#include <linux/pagemap.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <asm/uaccess.h>

#define I830_BUF_FREE		2
#define I830_BUF_CLIENT		1
#define I830_BUF_HARDWARE	0

#define I830_BUF_UNMAPPED 0
#define I830_BUF_MAPPED   1

static struct drm_buf *i830_freelist_get(struct drm_device * dev)
{
	struct drm_device_dma *dma = dev->dma;
	int i;
	int used;

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

	for (i = 0; i < dma->buf_count; i++) {
		struct drm_buf *buf = dma->buflist[i];
		drm_i830_buf_priv_t *buf_priv = buf->dev_private;
		/* In use is already a pointer */
		used = cmpxchg(buf_priv->in_use, I830_BUF_FREE,
			       I830_BUF_CLIENT);
		if (used == I830_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 i830_freelist_put(struct drm_device *dev, struct drm_buf *buf)
{
	drm_i830_buf_priv_t *buf_priv = buf->dev_private;
	int used;

	/* In use is already a pointer */
	used = cmpxchg(buf_priv->in_use, I830_BUF_CLIENT, I830_BUF_FREE);
	if (used != I830_BUF_CLIENT) {
		DRM_ERROR("Freeing buffer thats not in use : %d\n", buf->idx);
		return -EINVAL;
	}

	return 0;
}

static int i830_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
{
	struct drm_file *priv = filp->private_data;
	struct drm_device *dev;
	drm_i830_private_t *dev_priv;
	struct drm_buf *buf;
	drm_i830_buf_priv_t *buf_priv;

	lock_kernel();
	dev = priv->minor->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 = I830_BUF_MAPPED;
	unlock_kernel();

	if (io_remap_pfn_range(vma, vma->vm_start,
			       vma->vm_pgoff,
			       vma->vm_end - vma->vm_start, vma->vm_page_prot))
		return -EAGAIN;
	return 0;
}

static const struct file_operations i830_buffer_fops = {
	.open = drm_open,
	.release = drm_release,
	.unlocked_ioctl = i830_ioctl,
	.mmap = i830_mmap_buffers,
	.fasync = drm_fasync,
};

static int i830_map_buffer(struct drm_buf *buf, struct drm_file *file_priv)
{
	struct drm_device *dev = file_priv->minor->dev;
	drm_i830_buf_priv_t *buf_priv = buf->dev_private;
	drm_i830_private_t *dev_priv = dev->dev_private;
	const struct file_operations *old_fops;
	unsigned long virtual;
	int retcode = 0;

	if (buf_priv->currently_mapped == I830_BUF_MAPPED)
		return -EINVAL;

	down_write(&current->mm->mmap_sem);
	old_fops = file_priv->filp->f_op;
	file_priv->filp->f_op = &i830_buffer_fops;
	dev_priv->mmap_buffer = buf;
	virtual = do_mmap(file_priv->filp, 0, buf->total, PROT_READ | PROT_WRITE,
			  MAP_SHARED, buf->bus_address);
	dev_priv->mmap_buffer = NULL;
	file_priv->filp->f_op = old_fops;
	if (IS_ERR((void *)virtual)) {	/* ugh */
		/* Real error */
		DRM_ERROR("mmap error\n");
		retcode = PTR_ERR((void *)virtual);
		buf_priv->virtual = NULL;
	} else {
		buf_priv->virtual = (void __user *)virtual;
	}
	up_write(&current->mm->mmap_sem);

	return retcode;
}

static int i830_unmap_buffer(struct drm_buf *buf)
{
	drm_i830_buf_priv_t *buf_priv = buf->dev_private;
	int retcode = 0;

	if (buf_priv->currently_mapped != I830_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 = I830_BUF_UNMAPPED;
	buf_priv->virtual = NULL;

	return retcode;
}

static int i830_dma_get_buffer(struct drm_device *dev, drm_i830_dma_t *d,
			       struct drm_file *file_priv)
{
	struct drm_buf *buf;
	drm_i830_buf_priv_t *buf_priv;
	int retcode = 0;

	buf = i830_freelist_get(dev);
	if (!buf) {
		retcode = -ENOMEM;