drm_vm.c

底层驱动开发

/**
 * \file drm_vm.h
 * Memory mapping for DRM
 * 
 * \author Rickard E. (Rik) Faith <[e-mail]>
 * \author Gareth Hughes <[e-mail]>
 */

/*
 * Created: Mon Jan  4 08:58:31 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
 * VA LINUX SYSTEMS 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.
 */

#include "drmP.h"
#if defined(__ia64__)
#include <linux/efi.h>
#endif

static void drm_vm_open(struct vm_area_struct *vma);
static void drm_vm_close(struct vm_area_struct *vma);

/**
 * \c nopage method for AGP virtual memory.
 *
 * \param vma virtual memory area.
 * \param address access address.
 * \return pointer to the page structure.
 * 
 * Find the right map and if it's AGP memory find the real physical page to
 * map, get the page, increment the use count and return it.
 */
#if __OS_HAS_AGP
static __inline__ struct page *drm_do_vm_nopage(struct vm_area_struct *vma,
						 unsigned long address)
{
	drm_file_t *priv  = vma->vm_file->private_data;
	drm_device_t *dev = priv->head->dev;
	drm_map_t *map    = NULL;
	drm_map_list_t  *r_list;
	struct list_head *list;

	/*
         * Find the right map
         */
	if (!drm_core_has_AGP(dev))
		goto vm_nopage_error;

	if(!dev->agp || !dev->agp->cant_use_aperture) goto vm_nopage_error;

	list_for_each(list, &dev->maplist->head) {
		r_list = list_entry(list, drm_map_list_t, head);
		map = r_list->map;
		if (!map) continue;
		if (r_list->user_token == VM_OFFSET(vma))
			break;
	}

	if (map && map->type == _DRM_AGP) {
		unsigned long offset = address - vma->vm_start;
		unsigned long baddr = map->offset + offset;
		struct drm_agp_mem *agpmem;
		struct page *page;

#ifdef __alpha__
		/*
                 * Adjust to a bus-relative address
                 */
		baddr -= dev->hose->mem_space->start;
#endif

		/*
                 * It's AGP memory - find the real physical page to map
                 */
		for(agpmem = dev->agp->memory; agpmem; agpmem = agpmem->next) {
			if (agpmem->bound <= baddr &&
			    agpmem->bound + agpmem->pages * PAGE_SIZE > baddr) 
				break;
		}

		if (!agpmem) goto vm_nopage_error;

		/*
                 * Get the page, inc the use count, and return it
                 */
		offset = (baddr - agpmem->bound) >> PAGE_SHIFT;
		page = virt_to_page(__va(agpmem->memory->memory[offset]));
		get_page(page);

		DRM_DEBUG("baddr = 0x%lx page = 0x%p, offset = 0x%lx, count=%d\n",
			  baddr, __va(agpmem->memory->memory[offset]), offset,
			  page_count(page));

		return page;
        }
vm_nopage_error:
	return NOPAGE_SIGBUS;		/* Disallow mremap */
}
#else /* __OS_HAS_AGP */
static __inline__ struct page *drm_do_vm_nopage(struct vm_area_struct *vma,
						 unsigned long address)
{
	return NOPAGE_SIGBUS;
}
#endif /* __OS_HAS_AGP */

/**
 * \c nopage method for shared virtual memory.
 *
 * \param vma virtual memory area.
 * \param address access address.
 * \return pointer to the page structure.
 * 
 * Get the the mapping, find the real physical page to map, get the page, and
 * return it.
 */
static __inline__ struct page *drm_do_vm_shm_nopage(struct vm_area_struct *vma,
						     unsigned long address)
{
	drm_map_t	 *map	 = (drm_map_t *)vma->vm_private_data;
	unsigned long	 offset;
	unsigned long	 i;
	struct page	 *page;

	if (address > vma->vm_end) return NOPAGE_SIGBUS; /* Disallow mremap */
	if (!map)    		   return NOPAGE_OOM;  /* Nothing allocated */

	offset	 = address - vma->vm_start;
	i = (unsigned long)map->handle + offset;
	page = (map->type == _DRM_CONSISTENT) ?
		virt_to_page((void *)i) : vmalloc_to_page((void *)i);
	if (!page)
		return NOPAGE_OOM;
	get_page(page);

	DRM_DEBUG("shm_nopage 0x%lx\n", address);
	return page;
}


/**
 * \c close method for shared virtual memory.
 * 
 * \param vma virtual memory area.
 * 
 * Deletes map information if we are the last
 * person to close a mapping and it's not in the global maplist.
 */
static void drm_vm_shm_close(struct vm_area_struct *vma)
{
	drm_file_t	*priv	= vma->vm_file->private_data;
	drm_device_t	*dev	= priv->head->dev;
	drm_vma_entry_t *pt, *prev, *next;
	drm_map_t *map;
	drm_map_list_t *r_list;
	struct list_head *list;
	int found_maps = 0;

	DRM_DEBUG("0x%08lx,0x%08lx\n",
		  vma->vm_start, vma->vm_end - vma->vm_start);
	atomic_dec(&dev->vma_count);

	map = vma->vm_private_data;

	down(&dev->struct_sem);
	for (pt = dev->vmalist, prev = NULL; pt; pt = next) {
		next = pt->next;
		if (pt->vma->vm_private_data == map) found_maps++;
		if (pt->vma == vma) {
			if (prev) {
				prev->next = pt->next;
			} else {
				dev->vmalist = pt->next;
			}
			drm_free(pt, sizeof(*pt), DRM_MEM_VMAS);
		} else {
			prev = pt;
		}
	}
	/* We were the only map that was found */
	if(found_maps == 1 &&
	   map->flags & _DRM_REMOVABLE) {
		/* Check to see if we are in the maplist, if we are not, then
		 * we delete this mappings information.
		 */
		found_maps = 0;
		list = &dev->maplist->head;
		list_for_each(list, &dev->maplist->head) {
			r_list = list_entry(list, drm_map_list_t, head);
			if (r_list->map == map) found_maps++;
		}

		if(!found_maps) {
			drm_dma_handle_t dmah;

			switch (map->type) {
			case _DRM_REGISTERS:
			case _DRM_FRAME_BUFFER:
				if (drm_core_has_MTRR(dev) && map->mtrr >= 0) {
					int retcode;
					retcode = mtrr_del(map->mtrr,
							   map->offset,
							   map->size);
					DRM_DEBUG("mtrr_del = %d\n", retcode);
				}
				drm_ioremapfree(map->handle, map->size, dev);
				break;
			case _DRM_SHM:
				vfree(map->handle);
				break;
			case _DRM_AGP:
			case _DRM_SCATTER_GATHER:
				break;
			case _DRM_CONSISTENT:
				dmah.vaddr = map->handle;
				dmah.busaddr = map->offset;
				dmah.size = map->size;
				__drm_pci_free(dev, &dmah);
				break;
			}
			drm_free(map, sizeof(*map), DRM_MEM_MAPS);
		}
	}
	up(&dev->struct_sem);
}

/**
 * \c nopage method for DMA virtual memory.
 *
 * \param vma virtual memory area.
 * \param address access address.
 * \return pointer to the page structure.
 * 
 * Determine the page number from the page offset and get it from drm_device_dma::pagelist.
 */
static __inline__ struct page *drm_do_vm_dma_nopage(struct vm_area_struct *vma,
						     unsigned long address)
{
	drm_file_t	 *priv	 = vma->vm_file->private_data;
	drm_device_t	 *dev	 = priv->head->dev;
	drm_device_dma_t *dma	 = dev->dma;
	unsigned long	 offset;
	unsigned long	 page_nr;
	struct page	 *page;

	if (!dma)		   return NOPAGE_SIGBUS; /* Error */
	if (address > vma->vm_end) return NOPAGE_SIGBUS; /* Disallow mremap */
	if (!dma->pagelist)	   return NOPAGE_OOM ; /* Nothing allocated */

	offset	 = address - vma->vm_start; /* vm_[pg]off[set] should be 0 */
	page_nr  = offset >> PAGE_SHIFT;
	page = virt_to_page((dma->pagelist[page_nr] + 
			     (offset & (~PAGE_MASK))));

	get_page(page);

	DRM_DEBUG("dma_nopage 0x%lx (page %lu)\n", address, page_nr);
	return page;
}

/**
 * \c nopage method for scatter-gather virtual memory.
 *
 * \param vma virtual memory area.
 * \param address access address.
 * \return pointer to the page structure.
 * 
 * Determine the map offset from the page offset and get it from drm_sg_mem::pagelist.
 */
static __inline__ struct page *drm_do_vm_sg_nopage(struct vm_area_struct *vma,
						    unsigned long address)
{
	drm_map_t        *map    = (drm_map_t *)vma->vm_private_data;
	drm_file_t *priv = vma->vm_file->private_data;
	drm_device_t *dev = priv->head->dev;
	drm_sg_mem_t *entry = dev->sg;
	unsigned long offset;
	unsigned long map_offset;
	unsigned long page_offset;
	struct page *page;

	if (!entry)                return NOPAGE_SIGBUS; /* Error */
	if (address > vma->vm_end) return NOPAGE_SIGBUS; /* Disallow mremap */
	if (!entry->pagelist)      return NOPAGE_OOM ;  /* Nothing allocated */


	offset = address - vma->vm_start;
	map_offset = map->offset - (unsigned long)dev->sg->virtual;
	page_offset = (offset >> PAGE_SHIFT) + (map_offset >> PAGE_SHIFT);
	page = entry->pagelist[page_offset];
	get_page(page);

	return page;
}


static struct page *drm_vm_nopage(struct vm_area_struct *vma,
				   unsigned long address,
				   int *type) {
	if (type) *type = VM_FAULT_MINOR;
	return drm_do_vm_nopage(vma, address);
}