/**
 * \file drm_bufs.c
 * Generic buffer template
 *
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 */

/*
 * Created: Thu Nov 23 03:10:50 2000 by gareth@valinux.com
 *
 * Copyright 1999, 2000 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 <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/log2.h>
#include <linux/export.h>
#include <asm/shmparam.h>
#include "drmP.h"

static struct drm_map_list *drm_find_matching_map(struct drm_device *dev,
                                                  struct drm_local_map *map)
{
        struct drm_map_list *entry;
        list_for_each_entry(entry, &dev->maplist, head) {
                /*
                 * Because the kernel-userspace ABI is fixed at a 32-bit offset
                 * while PCI resources may live above that, we only compare the
                 * lower 32 bits of the map offset for maps of type
                 * _DRM_FRAMEBUFFER or _DRM_REGISTERS.
                 * It is assumed that if a driver have more than one resource
                 * of each type, the lower 32 bits are different.
                 */
                if (!entry->map ||
                    map->type != entry->map->type ||
                    entry->master != dev->primary->master)
                        continue;
                switch (map->type) {
                case _DRM_SHM:
                        if (map->flags != _DRM_CONTAINS_LOCK)
                                break;
                        return entry;
                case _DRM_REGISTERS:
                case _DRM_FRAME_BUFFER:
                        if ((entry->map->offset & 0xffffffff) ==
                            (map->offset & 0xffffffff))
                                return entry;
                default: /* Make gcc happy */
                        ;
                }
                if (entry->map->offset == map->offset)
                        return entry;
        }

        return NULL;
}

static int drm_map_handle(struct drm_device *dev, struct drm_hash_item *hash,
                          unsigned long user_token, int hashed_handle, int shm)
{
        int use_hashed_handle, shift;
        unsigned long add;

#if (BITS_PER_LONG == 64)
        use_hashed_handle = ((user_token & 0xFFFFFFFF00000000UL) || hashed_handle);
#elif (BITS_PER_LONG == 32)
        use_hashed_handle = hashed_handle;
#else
#error Unsupported long size. Neither 64 nor 32 bits.
#endif

        if (!use_hashed_handle) {
                int ret;
                hash->key = user_token >> PAGE_SHIFT;
                ret = drm_ht_insert_item(&dev->map_hash, hash);
                if (ret != -EINVAL)
                        return ret;
        }

        shift = 0;
        add = DRM_MAP_HASH_OFFSET >> PAGE_SHIFT;
        if (shm && (SHMLBA > PAGE_SIZE)) {
                int bits = ilog2(SHMLBA >> PAGE_SHIFT) + 1;

                /* For shared memory, we have to preserve the SHMLBA
                 * bits of the eventual vma->vm_pgoff value during
                 * mmap().  Otherwise we run into cache aliasing problems
                 * on some platforms.  On these platforms, the pgoff of
                 * a mmap() request is used to pick a suitable virtual
                 * address for the mmap() region such that it will not
                 * cause cache aliasing problems.
                 *
                 * Therefore, make sure the SHMLBA relevant bits of the
                 * hash value we use are equal to those in the original
                 * kernel virtual address.
                 */
                shift = bits;
                add |= ((user_token >> PAGE_SHIFT) & ((1UL << bits) - 1UL));
        }

        return drm_ht_just_insert_please(&dev->map_hash, hash,
                                         user_token, 32 - PAGE_SHIFT - 3,
                                         shift, add);
}

/**
 * Core function to create a range of memory available for mapping by a
 * non-root process.
 *
 * Adjusts the memory offset to its absolute value according to the mapping
 * type.  Adds the map to the map list drm_device::maplist. Adds MTRR's where
 * applicable and if supported by the kernel.
 */
static int drm_addmap_core(struct drm_device * dev, resource_size_t offset,
                           unsigned int size, enum drm_map_type type,
                           enum drm_map_flags flags,
                           struct drm_map_list ** maplist)
{
        struct drm_local_map *map;
        struct drm_map_list *list;
        drm_dma_handle_t *dmah;
        unsigned long user_token;
        int ret;

        map = kmalloc(sizeof(*map), GFP_KERNEL);
        if (!map)
                return -ENOMEM;

        map->offset = offset;
        map->size = size;
        map->flags = flags;
        map->type = type;

        /* Only allow shared memory to be removable since we only keep enough
         * book keeping information about shared memory to allow for removal
         * when processes fork.
         */
        if ((map->flags & _DRM_REMOVABLE) && map->type != _DRM_SHM) {
                kfree(map);
                return -EINVAL;
        }
        DRM_DEBUG("offset = 0x%08llx, size = 0x%08lx, type = %d\n",
                  (unsigned long long)map->offset, map->size, map->type);

        /* page-align _DRM_SHM maps. They are allocated here so there is no security
         * hole created by that and it works around various broken drivers that use
         * a non-aligned quantity to map the SAREA. --BenH
         */
        if (map->type == _DRM_SHM)
                map->size = PAGE_ALIGN(map->size);

        if ((map->offset & (~(resource_size_t)PAGE_MASK)) || (map->size & (~PAGE_MASK))) {
                kfree(map);
                return -EINVAL;
        }
        map->mtrr = -1;
        map->handle = NULL;

        switch (map->type) {
        case _DRM_REGISTERS:
        case _DRM_FRAME_BUFFER:
#if !defined(__sparc__) && !defined(__alpha__) && !defined(__ia64__) && !defined(__powerpc64__) && !defined(__x86_64__) && !defined(__arm__)
                if (map->offset + (map->size-1) < map->offset ||
                    map->offset < virt_to_phys(high_memory)) {
                        kfree(map);
                        return -EINVAL;
                }
#endif
                /* Some drivers preinitialize some maps, without the X Server
                 * needing to be aware of it.  Therefore, we just return success
                 * when the server tries to create a duplicate map.
                 */
                list = drm_find_matching_map(dev, map);
                if (list != NULL) {
                        if (list->map->size != map->size) {
                                DRM_DEBUG("Matching maps of type %d with "
                                          "mismatched sizes, (%ld vs %ld)\n",
                                          map->type, map->size,
                                          list->map->size);
                                list->map->size = map->size;
                        }

                        kfree(map);
                        *maplist = list;
                        return 0;
                }

                if (drm_core_has_MTRR(dev)) {
                        if (map->type == _DRM_FRAME_BUFFER ||
                            (map->flags & _DRM_WRITE_COMBINING)) {
                                map->mtrr = mtrr_add(map->offset, map->size,
                                                     MTRR_TYPE_WRCOMB, 1);
                        }
                }
                if (map->type == _DRM_REGISTERS) {
                        map->handle = ioremap(map->offset, map->size);
                        if (!map->handle) {
                                kfree(map);
                                return -ENOMEM;
                        }
                }

                break;
        case _DRM_SHM:
                list = drm_find_matching_map(dev, map);
                if (list != NULL) {
                        if(list->map->size != map->size) {
                                DRM_DEBUG("Matching maps of type %d with "
                                          "mismatched sizes, (%ld vs %ld)\n",
                                          map->type, map->size, list->map->size);
                                list->map->size = map->size;
                        }

                        kfree(map);
                        *maplist = list;
                        return 0;
                }
                map->handle = vmalloc_user(map->size);
                DRM_DEBUG("%lu %d %p\n",
                          map->size, drm_order(map->size), map->handle);
                if (!map->handle) {
                        kfree(map);
                        return -ENOMEM;
                }
                map->offset = (unsigned long)map->handle;
                if (map->flags & _DRM_CONTAINS_LOCK) {
                        /* Prevent a 2nd X Server from creating a 2nd lock */
                        if (dev->primary->master->lock.hw_lock != NULL) {
                                vfree(map->handle);
                                kfree(map);
                                return -EBUSY;
                        }
                        dev->sigdata.lock = dev->primary->master->lock.hw_lock = map->handle;   /* Pointer to lock */
                }
                break;
        case _DRM_AGP: {
                struct drm_agp_mem *entry;
                int valid = 0;

                if (!drm_core_has_AGP(dev)) {
                        kfree(map);
                        return -EINVAL;
                }
#ifdef __alpha__
                map->offset += dev->hose->mem_space->start;
#endif
                /* In some cases (i810 driver), user space may have already
                 * added the AGP base itself, because dev->agp->base previously
                 * only got set during AGP enable.  So, only add the base
                 * address if the map's offset isn't already within the
                 * aperture.
                 */
                if (map->offset < dev->agp->base ||
                    map->offset > dev->agp->base +
                    dev->agp->agp_info.aper_size * 1024 * 1024 - 1) {
                        map->offset += dev->agp->base;
                }
                map->mtrr = dev->agp->agp_mtrr; /* for getmap */

                /* This assumes the DRM is in total control of AGP space.
                 * It's not always the case as AGP can be in the control
                 * of user space (i.e. i810 driver). So this loop will get
                 * skipped and we double check that dev->agp->memory is
                 * actually set as well as being invalid before EPERM'ing
                 */
                list_for_each_entry(entry, &dev->agp->memory, head) {
                        if ((map->offset >= entry->bound) &&
                            (map->offset + map->size <= entry->bound + entry->pages * PAGE_SIZE)) {
                                valid = 1;
                                break;
                        }
                }
                if (!list_empty(&dev->agp->memory) && !valid) {
                        kfree(map);
                        return -EPERM;
                }
                DRM_DEBUG("AGP offset = 0x%08llx, size = 0x%08lx\n",
                          (unsigned long long)map->offset, map->size);

                break;
        }
        case _DRM_GEM:
                DRM_ERROR("tried to addmap GEM object\n");
                break;
        case _DRM_SCATTER_GATHER:
                if (!dev->sg) {
                        kfree(map);
                        return -EINVAL;
                }
                map->offset += (unsigned long)dev->sg->virtual;
                break;
        case _DRM_CONSISTENT:
                /* dma_addr_t is 64bit on i386 with CONFIG_HIGHMEM64G,
                 * As we're limiting the address to 2^32-1 (or less),
                 * casting it down to 32 bits is no problem, but we
                 * need to point to a 64bit variable first. */
                dmah = drm_pci_alloc(dev, map->size, map->size);
                if (!dmah) {
                        kfree(map);
                        return -ENOMEM;
                }
                map->handle = dmah->vaddr;
                map->offset = (unsigned long)dmah->busaddr;
                kfree(dmah);
                break;
        default:
                kfree(map);
                return -EINVAL;
        }

        list = kzalloc(sizeof(*list), GFP_KERNEL);
        if (!list) {
                if (map->type == _DRM_REGISTERS)
                        iounmap(map->handle);
                kfree(map);
                return -EINVAL;
        }
        list->map = map;

        mutex_lock(&dev->struct_mutex);
        list_add(&list->head, &dev->maplist);

        /* Assign a 32-bit handle */
        /* We do it here so that dev->struct_mutex protects the increment */
        user_token = (map->type == _DRM_SHM) ? (unsigned long)map->handle :
                map->offset;
        ret = drm_map_handle(dev, &list->hash, user_token, 0,
                             (map->type == _DRM_SHM));
        if (ret) {
                if (map->type == _DRM_REGISTERS)
                        iounmap(map->handle);
                kfree(map);
                kfree(list);
                mutex_unlock(&dev->struct_mutex);
                return ret;
        }

        list->user_token = list->hash.key << PAGE_SHIFT;
        mutex_unlock(&dev->struct_mutex);

        if (!(map->flags & _DRM_DRIVER))
                list->master = dev->primary->master;
        *maplist = list;
        return 0;
        }

int drm_addmap(struct drm_device * dev, resource_size_t offset,
               unsigned int size, enum drm_map_type type,
               enum drm_map_flags flags, struct drm_local_map ** map_ptr)
{
        struct drm_map_list *list;
        int rc;

        rc = drm_addmap_core(dev, offset, size, type, flags, &list);
        if (!rc)
                *map_ptr = list->map;
        return rc;
}

EXPORT_SYMBOL(drm_addmap);

/**
 * Ioctl to specify a range of memory that is available for mapping by a
 * non-root process.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg pointer to a drm_map structure.
 * \return zero on success or a negative value on error.
 *
 */
int drm_addmap_ioctl(struct drm_device *dev, void *data,
                     struct drm_file *file_priv)
{
        struct drm_map *map = data;
        struct drm_map_list *maplist;
        int err;

        if (!(capable(CAP_SYS_ADMIN) || map->type == _DRM_AGP || map->type == _DRM_SHM))
                return -EPERM;

        err = drm_addmap_core(dev, map->offset, map->size, map->type,
                              map->flags, &maplist);

        if (err)
                return err;

        /* avoid a warning on 64-bit, this casting isn't very nice, but the API is set so too late */
        map->handle = (void *)(unsigned long)maplist->user_token;
        return 0;
}

/**
 * Remove a map private from list and deallocate resources if the mapping
 * isn't in use.
 *
 * Searches the map on drm_device::maplist, removes it from the list, see if
 * its being used, and free any associate resource (such as MTRR's) if it's not
 * being on use.
 *
 * \sa drm_addmap
 */
int drm_rmmap_locked(struct drm_device *dev, struct drm_local_map *map)
{
        struct drm_map_list *r_list = NULL, *list_t;
        drm_dma_handle_t dmah;
        int found = 0;
        struct drm_master *master;

        /* Find the list entry for the map and remove it */
        list_for_each_entry_safe(r_list, list_t, &dev->maplist, head) {
                if (r_list->map == map) {
                        master = r_list->master;
                        list_del(&r_list->head);
                        drm_ht_remove_key(&dev->map_hash,
                                          r_list->user_token >> PAGE_SHIFT);
                        kfree(r_list);
                        found = 1;
                        break;
                }
        }

        if (!found)
                return -EINVAL;

        switch (map->type) {
        case _DRM_REGISTERS:
                iounmap(map->handle);
                /* FALLTHROUGH */
        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);
                }
                break;
        case _DRM_SHM:
                vfree(map->handle);
                if (master) {
                        if (dev->sigdata.lock == master->lock.hw_lock)
                                dev->sigdata.lock = NULL;
                        master->lock.hw_lock = NULL;   /* SHM removed */
                        master->lock.file_priv = NULL;
                        wake_up_interruptible_all(&master->lock.lock_queue);
                }
                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;
        case _DRM_GEM:
                DRM_ERROR("tried to rmmap GEM object\n");
                break;
        }
        kfree(map);

        return 0;
}
EXPORT_SYMBOL(drm_rmmap_locked);

int drm_rmmap(struct drm_device *dev, struct drm_local_map *map)
{
        int ret;

        mutex_lock(&dev->struct_mutex);
        ret = drm_rmmap_locked(dev, map);
        mutex_unlock(&dev->struct_mutex);

        return ret;
}
EXPORT_SYMBOL(drm_rmmap);

/* The rmmap ioctl appears to be unnecessary.  All mappings are torn down on
 * the last close of the device, and this is necessary for cleanup when things
 * exit uncleanly.  Therefore, having userland manually remove mappings seems
 * like a pointless exercise since they're going away anyway.
 *
 * One use case might be after addmap is allowed for normal users for SHM and
 * gets used by drivers that the server doesn't need to care about.  This seems
 * unlikely.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg pointer to a struct drm_map structure.
 * \return zero on success or a negative value on error.
 */
int drm_rmmap_ioctl(struct drm_device *dev, void *data,
                    struct drm_file *file_priv)
{
        struct drm_map *request = data;
        struct drm_local_map *map = NULL;
        struct drm_map_list *r_list;
        int ret;

        mutex_lock(&dev->struct_mutex);
        list_for_each_entry(r_list, &dev->maplist, head) {
                if (r_list->map &&
                    r_list->user_token == (unsigned long)request->handle &&
                    r_list->map->flags & _DRM_REMOVABLE) {
                        map = r_list->map;
                        break;
                }
        }

        /* List has wrapped around to the head pointer, or its empty we didn't
         * find anything.
         */
        if (list_empty(&dev->maplist) || !map) {
                mutex_unlock(&dev->struct_mutex);
                return -EINVAL;
        }

        /* Register and framebuffer maps are permanent */
        if ((map->type == _DRM_REGISTERS) || (map->type == _DRM_FRAME_BUFFER)) {
                mutex_unlock(&dev->struct_mutex);
                return 0;
        }

        ret = drm_rmmap_locked(dev, map);

        mutex_unlock(&dev->struct_mutex);

        return ret;
}

/**
 * Cleanup after an error on one of the addbufs() functions.
 *
 * \param dev DRM device.
 * \param entry buffer entry where the error occurred.
 *
 * Frees any pages and buffers associated with the given entry.
 */
static void drm_cleanup_buf_error(struct drm_device * dev,
                                  struct drm_buf_entry * entry)
{
        int i;

        if (entry->seg_count) {
                for (i = 0; i < entry->seg_count; i++) {
                        if (entry->seglist[i]) {
                                drm_pci_free(dev, entry->seglist[i]);
                        }
                }
                kfree(entry->seglist);

                entry->seg_count = 0;
        }

        if (entry->buf_count) {
                for (i = 0; i < entry->buf_count; i++) {
                        kfree(entry->buflist[i].dev_private);
                }
                kfree(entry->buflist);

                entry->buf_count = 0;
        }
}

#if __OS_HAS_AGP
/**
 * Add AGP buffers for DMA transfers.
 *
 * \param dev struct drm_device to which the buffers are to be added.
 * \param request pointer to a struct drm_buf_desc describing the request.
 * \return zero on success or a negative number on failure.
 *
 * After some sanity checks creates a drm_buf structure for each buffer and
 * reallocates the buffer list of the same size order to accommodate the new
 * buffers.
 */
int drm_addbufs_agp(struct drm_device * dev, struct drm_buf_desc * request)
{
        struct drm_device_dma *dma = dev->dma;
        struct drm_buf_entry *entry;
        struct drm_agp_mem *agp_entry;
        struct drm_buf *buf;
        unsigned long offset;
        unsigned long agp_offset;
        int count;
        int order;
        int size;
        int alignment;
        int page_order;
        int total;
        int byte_count;
        int i, valid;
        struct drm_buf **temp_buflist;

        if (!dma)
                return -EINVAL;

        count = request->count;
        order = drm_order(request->size);
        size = 1 << order;

        alignment = (request->flags & _DRM_PAGE_ALIGN)
            ? PAGE_ALIGN(size) : size;
        page_order = order - PAGE_SHIFT > 0 ? order - PAGE_SHIFT : 0;
        total = PAGE_SIZE << page_order;

        byte_count = 0;
        agp_offset = dev->agp->base + request->agp_start;

        DRM_DEBUG("count:      %d\n", count);
        DRM_DEBUG("order:      %d\n", order);
        DRM_DEBUG("size:       %d\n", size);
        DRM_DEBUG("agp_offset: %lx\n", agp_offset);
        DRM_DEBUG("alignment:  %d\n", alignment);
        DRM_DEBUG("page_order: %d\n", page_order);
        DRM_DEBUG("total:      %d\n", total);

        if (order < DRM_MIN_ORDER || order > DRM_MAX_ORDER)
                return -EINVAL;
        if (dev->queue_count)
                return -EBUSY;  /* Not while in use */

        /* Make sure buffers are located in AGP memory that we own */
        valid = 0;
        list_for_each_entry(agp_entry, &dev->agp->memory, head) {
                if ((agp_offset >= agp_entry->bound) &&
                    (agp_offset + total * count <= agp_entry->bound + agp_entry->pages * PAGE_SIZE)) {
                        valid = 1;
                        break;
                }
        }
        if (!list_empty(&dev->agp->memory) && !valid) {
                DRM_DEBUG("zone invalid\n");
                return -EINVAL;
        }
        spin_lock(&dev->count_lock);
        if (dev->buf_use) {
                spin_unlock(&dev->count_lock);
                return -EBUSY;
        }
        atomic_inc(&dev->buf_alloc);
        spin_unlock(&dev->count_lock);

        mutex_lock(&dev->struct_mutex);
        entry = &dma->bufs[order];
        if (entry->buf_count) {
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM; /* May only call once for each order */
        }

        if (count < 0 || count > 4096) {
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -EINVAL;
        }

        entry->buflist = kzalloc(count * sizeof(*entry->buflist), GFP_KERNEL);
        if (!entry->buflist) {
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM;
        }

        entry->buf_size = size;
        entry->page_order = page_order;

        offset = 0;

        while (entry->buf_count < count) {
                buf = &entry->buflist[entry->buf_count];
                buf->idx = dma->buf_count + entry->buf_count;
                buf->total = alignment;
                buf->order = order;
                buf->used = 0;

                buf->offset = (dma->byte_count + offset);
                buf->bus_address = agp_offset + offset;
                buf->address = (void *)(agp_offset + offset);
                buf->next = NULL;
                buf->waiting = 0;
                buf->pending = 0;
                init_waitqueue_head(&buf->dma_wait);
                buf->file_priv = NULL;

                buf->dev_priv_size = dev->driver->dev_priv_size;
                buf->dev_private = kzalloc(buf->dev_priv_size, GFP_KERNEL);
                if (!buf->dev_private) {
                        /* Set count correctly so we free the proper amount. */
                        entry->buf_count = count;
                        drm_cleanup_buf_error(dev, entry);
                        mutex_unlock(&dev->struct_mutex);
                        atomic_dec(&dev->buf_alloc);
                        return -ENOMEM;
                }

                DRM_DEBUG("buffer %d @ %p\n", entry->buf_count, buf->address);

                offset += alignment;
                entry->buf_count++;
                byte_count += PAGE_SIZE << page_order;
        }

        DRM_DEBUG("byte_count: %d\n", byte_count);

        temp_buflist = krealloc(dma->buflist,
                                (dma->buf_count + entry->buf_count) *
                                sizeof(*dma->buflist), GFP_KERNEL);
        if (!temp_buflist) {
                /* Free the entry because it isn't valid */
                drm_cleanup_buf_error(dev, entry);
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM;
        }
        dma->buflist = temp_buflist;

        for (i = 0; i < entry->buf_count; i++) {
                dma->buflist[i + dma->buf_count] = &entry->buflist[i];
        }

        dma->buf_count += entry->buf_count;
        dma->seg_count += entry->seg_count;
        dma->page_count += byte_count >> PAGE_SHIFT;
        dma->byte_count += byte_count;

        DRM_DEBUG("dma->buf_count : %d\n", dma->buf_count);
        DRM_DEBUG("entry->buf_count : %d\n", entry->buf_count);

        mutex_unlock(&dev->struct_mutex);

        request->count = entry->buf_count;
        request->size = size;

        dma->flags = _DRM_DMA_USE_AGP;

        atomic_dec(&dev->buf_alloc);
        return 0;
}
EXPORT_SYMBOL(drm_addbufs_agp);
#endif                          /* __OS_HAS_AGP */

int drm_addbufs_pci(struct drm_device * dev, struct drm_buf_desc * request)
{
        struct drm_device_dma *dma = dev->dma;
        int count;
        int order;
        int size;
        int total;
        int page_order;
        struct drm_buf_entry *entry;
        drm_dma_handle_t *dmah;
        struct drm_buf *buf;
        int alignment;
        unsigned long offset;
        int i;
        int byte_count;
        int page_count;
        unsigned long *temp_pagelist;
        struct drm_buf **temp_buflist;

        if (!drm_core_check_feature(dev, DRIVER_PCI_DMA))
                return -EINVAL;

        if (!dma)
                return -EINVAL;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        count = request->count;
        order = drm_order(request->size);
        size = 1 << order;

        DRM_DEBUG("count=%d, size=%d (%d), order=%d, queue_count=%d\n",
                  request->count, request->size, size, order, dev->queue_count);

        if (order < DRM_MIN_ORDER || order > DRM_MAX_ORDER)
                return -EINVAL;
        if (dev->queue_count)
                return -EBUSY;  /* Not while in use */

        alignment = (request->flags & _DRM_PAGE_ALIGN)
            ? PAGE_ALIGN(size) : size;
        page_order = order - PAGE_SHIFT > 0 ? order - PAGE_SHIFT : 0;
        total = PAGE_SIZE << page_order;

        spin_lock(&dev->count_lock);
        if (dev->buf_use) {
                spin_unlock(&dev->count_lock);
                return -EBUSY;
        }
        atomic_inc(&dev->buf_alloc);
        spin_unlock(&dev->count_lock);

        mutex_lock(&dev->struct_mutex);
        entry = &dma->bufs[order];
        if (entry->buf_count) {
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM; /* May only call once for each order */
        }

        if (count < 0 || count > 4096) {
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -EINVAL;
        }

        entry->buflist = kzalloc(count * sizeof(*entry->buflist), GFP_KERNEL);
        if (!entry->buflist) {
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM;
        }

        entry->seglist = kzalloc(count * sizeof(*entry->seglist), GFP_KERNEL);
        if (!entry->seglist) {
                kfree(entry->buflist);
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM;
        }

        /* Keep the original pagelist until we know all the allocations
         * have succeeded
         */
        temp_pagelist = kmalloc((dma->page_count + (count << page_order)) *
                               sizeof(*dma->pagelist), GFP_KERNEL);
        if (!temp_pagelist) {
                kfree(entry->buflist);
                kfree(entry->seglist);
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM;
        }
        memcpy(temp_pagelist,
               dma->pagelist, dma->page_count * sizeof(*dma->pagelist));
        DRM_DEBUG("pagelist: %d entries\n",
                  dma->page_count + (count << page_order));

        entry->buf_size = size;
        entry->page_order = page_order;
        byte_count = 0;
        page_count = 0;

        while (entry->buf_count < count) {

                dmah = drm_pci_alloc(dev, PAGE_SIZE << page_order, 0x1000);

                if (!dmah) {
                        /* Set count correctly so we free the proper amount. */
                        entry->buf_count = count;
                        entry->seg_count = count;
                        drm_cleanup_buf_error(dev, entry);
                        kfree(temp_pagelist);
                        mutex_unlock(&dev->struct_mutex);
                        atomic_dec(&dev->buf_alloc);
                        return -ENOMEM;
                }
                entry->seglist[entry->seg_count++] = dmah;
                for (i = 0; i < (1 << page_order); i++) {
                        DRM_DEBUG("page %d @ 0x%08lx\n",
                                  dma->page_count + page_count,
                                  (unsigned long)dmah->vaddr + PAGE_SIZE * i);
                        temp_pagelist[dma->page_count + page_count++]
                                = (unsigned long)dmah->vaddr + PAGE_SIZE * i;
                }
                for (offset = 0;
                     offset + size <= total && entry->buf_count < count;
                     offset += alignment, ++entry->buf_count) {
                        buf = &entry->buflist[entry->buf_count];
                        buf->idx = dma->buf_count + entry->buf_count;
                        buf->total = alignment;
                        buf->order = order;
                        buf->used = 0;
                        buf->offset = (dma->byte_count + byte_count + offset);
                        buf->address = (void *)(dmah->vaddr + offset);
                        buf->bus_address = dmah->busaddr + offset;
                        buf->next = NULL;
                        buf->waiting = 0;
                        buf->pending = 0;
                        init_waitqueue_head(&buf->dma_wait);
                        buf->file_priv = NULL;

                        buf->dev_priv_size = dev->driver->dev_priv_size;
                        buf->dev_private = kzalloc(buf->dev_priv_size,
                                                GFP_KERNEL);
                        if (!buf->dev_private) {
                                /* Set count correctly so we free the proper amount. */
                                entry->buf_count = count;
                                entry->seg_count = count;
                                drm_cleanup_buf_error(dev, entry);
                                kfree(temp_pagelist);
                                mutex_unlock(&dev->struct_mutex);
                                atomic_dec(&dev->buf_alloc);
                                return -ENOMEM;
                        }

                        DRM_DEBUG("buffer %d @ %p\n",
                                  entry->buf_count, buf->address);
                }
                byte_count += PAGE_SIZE << page_order;
        }

        temp_buflist = krealloc(dma->buflist,
                                (dma->buf_count + entry->buf_count) *
                                sizeof(*dma->buflist), GFP_KERNEL);
        if (!temp_buflist) {
                /* Free the entry because it isn't valid */
                drm_cleanup_buf_error(dev, entry);
                kfree(temp_pagelist);
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM;
        }
        dma->buflist = temp_buflist;

        for (i = 0; i < entry->buf_count; i++) {
                dma->buflist[i + dma->buf_count] = &entry->buflist[i];
        }

        /* No allocations failed, so now we can replace the original pagelist
         * with the new one.
         */
        if (dma->page_count) {
                kfree(dma->pagelist);
        }
        dma->pagelist = temp_pagelist;

        dma->buf_count += entry->buf_count;
        dma->seg_count += entry->seg_count;
        dma->page_count += entry->seg_count << page_order;
        dma->byte_count += PAGE_SIZE * (entry->seg_count << page_order);

        mutex_unlock(&dev->struct_mutex);

        request->count = entry->buf_count;
        request->size = size;

        if (request->flags & _DRM_PCI_BUFFER_RO)
                dma->flags = _DRM_DMA_USE_PCI_RO;

        atomic_dec(&dev->buf_alloc);
        return 0;

}
EXPORT_SYMBOL(drm_addbufs_pci);

static int drm_addbufs_sg(struct drm_device * dev, struct drm_buf_desc * request)
{
        struct drm_device_dma *dma = dev->dma;
        struct drm_buf_entry *entry;
        struct drm_buf *buf;
        unsigned long offset;
        unsigned long agp_offset;
        int count;
        int order;
        int size;
        int alignment;
        int page_order;
        int total;
        int byte_count;
        int i;
        struct drm_buf **temp_buflist;

        if (!drm_core_check_feature(dev, DRIVER_SG))
                return -EINVAL;

        if (!dma)
                return -EINVAL;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        count = request->count;

        order = drm_order(request->size);
        size = 1 << order;

        alignment = (request->flags & _DRM_PAGE_ALIGN)
            ? PAGE_ALIGN(size) : size;
        page_order = order - PAGE_SHIFT > 0 ? order - PAGE_SHIFT : 0;
        total = PAGE_SIZE << page_order;

        byte_count = 0;
        agp_offset = request->agp_start;

        DRM_DEBUG("count:      %d\n", count);
        DRM_DEBUG("order:      %d\n", order);
        DRM_DEBUG("size:       %d\n", size);
        DRM_DEBUG("agp_offset: %lu\n", agp_offset);
        DRM_DEBUG("alignment:  %d\n", alignment);
        DRM_DEBUG("page_order: %d\n", page_order);
        DRM_DEBUG("total:      %d\n", total);

        if (order < DRM_MIN_ORDER || order > DRM_MAX_ORDER)
                return -EINVAL;
        if (dev->queue_count)
                return -EBUSY;  /* Not while in use */

        spin_lock(&dev->count_lock);
        if (dev->buf_use) {
                spin_unlock(&dev->count_lock);
                return -EBUSY;
        }
        atomic_inc(&dev->buf_alloc);
        spin_unlock(&dev->count_lock);

        mutex_lock(&dev->struct_mutex);
        entry = &dma->bufs[order];
        if (entry->buf_count) {
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM; /* May only call once for each order */
        }

        if (count < 0 || count > 4096) {
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -EINVAL;
        }

        entry->buflist = kzalloc(count * sizeof(*entry->buflist),
                                GFP_KERNEL);
        if (!entry->buflist) {
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM;
        }

        entry->buf_size = size;
        entry->page_order = page_order;

        offset = 0;

        while (entry->buf_count < count) {
                buf = &entry->buflist[entry->buf_count];
                buf->idx = dma->buf_count + entry->buf_count;
                buf->total = alignment;
                buf->order = order;
                buf->used = 0;

                buf->offset = (dma->byte_count + offset);
                buf->bus_address = agp_offset + offset;
                buf->address = (void *)(agp_offset + offset
                                        + (unsigned long)dev->sg->virtual);
                buf->next = NULL;
                buf->waiting = 0;
                buf->pending = 0;
                init_waitqueue_head(&buf->dma_wait);
                buf->file_priv = NULL;

                buf->dev_priv_size = dev->driver->dev_priv_size;
                buf->dev_private = kzalloc(buf->dev_priv_size, GFP_KERNEL);
                if (!buf->dev_private) {
                        /* Set count correctly so we free the proper amount. */
                        entry->buf_count = count;
                        drm_cleanup_buf_error(dev, entry);
                        mutex_unlock(&dev->struct_mutex);
                        atomic_dec(&dev->buf_alloc);
                        return -ENOMEM;
                }

                DRM_DEBUG("buffer %d @ %p\n", entry->buf_count, buf->address);

                offset += alignment;
                entry->buf_count++;
                byte_count += PAGE_SIZE << page_order;
        }

        DRM_DEBUG("byte_count: %d\n", byte_count);

        temp_buflist = krealloc(dma->buflist,
                                (dma->buf_count + entry->buf_count) *
                                sizeof(*dma->buflist), GFP_KERNEL);
        if (!temp_buflist) {
                /* Free the entry because it isn't valid */
                drm_cleanup_buf_error(dev, entry);
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM;
        }
        dma->buflist = temp_buflist;

        for (i = 0; i < entry->buf_count; i++) {
                dma->buflist[i + dma->buf_count] = &entry->buflist[i];
        }

        dma->buf_count += entry->buf_count;
        dma->seg_count += entry->seg_count;
        dma->page_count += byte_count >> PAGE_SHIFT;
        dma->byte_count += byte_count;

        DRM_DEBUG("dma->buf_count : %d\n", dma->buf_count);
        DRM_DEBUG("entry->buf_count : %d\n", entry->buf_count);

        mutex_unlock(&dev->struct_mutex);

        request->count = entry->buf_count;
        request->size = size;

        dma->flags = _DRM_DMA_USE_SG;

        atomic_dec(&dev->buf_alloc);
        return 0;
}

static int drm_addbufs_fb(struct drm_device * dev, struct drm_buf_desc * request)
{
        struct drm_device_dma *dma = dev->dma;
        struct drm_buf_entry *entry;
        struct drm_buf *buf;
        unsigned long offset;
        unsigned long agp_offset;
        int count;
        int order;
        int size;
        int alignment;
        int page_order;
        int total;
        int byte_count;
        int i;
        struct drm_buf **temp_buflist;

        if (!drm_core_check_feature(dev, DRIVER_FB_DMA))
                return -EINVAL;

        if (!dma)
                return -EINVAL;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        count = request->count;
        order = drm_order(request->size);
        size = 1 << order;

        alignment = (request->flags & _DRM_PAGE_ALIGN)
            ? PAGE_ALIGN(size) : size;
        page_order = order - PAGE_SHIFT > 0 ? order - PAGE_SHIFT : 0;
        total = PAGE_SIZE << page_order;

        byte_count = 0;
        agp_offset = request->agp_start;

        DRM_DEBUG("count:      %d\n", count);
        DRM_DEBUG("order:      %d\n", order);
        DRM_DEBUG("size:       %d\n", size);
        DRM_DEBUG("agp_offset: %lu\n", agp_offset);
        DRM_DEBUG("alignment:  %d\n", alignment);
        DRM_DEBUG("page_order: %d\n", page_order);
        DRM_DEBUG("total:      %d\n", total);

        if (order < DRM_MIN_ORDER || order > DRM_MAX_ORDER)
                return -EINVAL;
        if (dev->queue_count)
                return -EBUSY;  /* Not while in use */

        spin_lock(&dev->count_lock);
        if (dev->buf_use) {
                spin_unlock(&dev->count_lock);
                return -EBUSY;
        }
        atomic_inc(&dev->buf_alloc);
        spin_unlock(&dev->count_lock);

        mutex_lock(&dev->struct_mutex);
        entry = &dma->bufs[order];
        if (entry->buf_count) {
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM; /* May only call once for each order */
        }

        if (count < 0 || count > 4096) {
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -EINVAL;
        }

        entry->buflist = kzalloc(count * sizeof(*entry->buflist),
                                GFP_KERNEL);
        if (!entry->buflist) {
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM;
        }

        entry->buf_size = size;
        entry->page_order = page_order;

        offset = 0;

        while (entry->buf_count < count) {
                buf = &entry->buflist[entry->buf_count];
                buf->idx = dma->buf_count + entry->buf_count;
                buf->total = alignment;
                buf->order = order;
                buf->used = 0;

                buf->offset = (dma->byte_count + offset);
                buf->bus_address = agp_offset + offset;
                buf->address = (void *)(agp_offset + offset);
                buf->next = NULL;
                buf->waiting = 0;
                buf->pending = 0;
                init_waitqueue_head(&buf->dma_wait);
                buf->file_priv = NULL;

                buf->dev_priv_size = dev->driver->dev_priv_size;
                buf->dev_private = kzalloc(buf->dev_priv_size, GFP_KERNEL);
                if (!buf->dev_private) {
                        /* Set count correctly so we free the proper amount. */
                        entry->buf_count = count;
                        drm_cleanup_buf_error(dev, entry);
                        mutex_unlock(&dev->struct_mutex);
                        atomic_dec(&dev->buf_alloc);
                        return -ENOMEM;
                }

                DRM_DEBUG("buffer %d @ %p\n", entry->buf_count, buf->address);

                offset += alignment;
                entry->buf_count++;
                byte_count += PAGE_SIZE << page_order;
        }

        DRM_DEBUG("byte_count: %d\n", byte_count);

        temp_buflist = krealloc(dma->buflist,
                                (dma->buf_count + entry->buf_count) *
                                sizeof(*dma->buflist), GFP_KERNEL);
        if (!temp_buflist) {
                /* Free the entry because it isn't valid */
                drm_cleanup_buf_error(dev, entry);
                mutex_unlock(&dev->struct_mutex);
                atomic_dec(&dev->buf_alloc);
                return -ENOMEM;
        }
        dma->buflist = temp_buflist;

        for (i = 0; i < entry->buf_count; i++) {
                dma->buflist[i + dma->buf_count] = &entry->buflist[i];
        }

        dma->buf_count += entry->buf_count;
        dma->seg_count += entry->seg_count;
        dma->page_count += byte_count >> PAGE_SHIFT;
        dma->byte_count += byte_count;

        DRM_DEBUG("dma->buf_count : %d\n", dma->buf_count);
        DRM_DEBUG("entry->buf_count : %d\n", entry->buf_count);

        mutex_unlock(&dev->struct_mutex);

        request->count = entry->buf_count;
        request->size = size;

        dma->flags = _DRM_DMA_USE_FB;

        atomic_dec(&dev->buf_alloc);
        return 0;
}


/**
 * Add buffers for DMA transfers (ioctl).
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg pointer to a struct drm_buf_desc request.
 * \return zero on success or a negative number on failure.
 *
 * According with the memory type specified in drm_buf_desc::flags and the
 * build options, it dispatches the call either to addbufs_agp(),
 * addbufs_sg() or addbufs_pci() for AGP, scatter-gather or consistent
 * PCI memory respectively.
 */
int drm_addbufs(struct drm_device *dev, void *data,
                struct drm_file *file_priv)
{
        struct drm_buf_desc *request = data;
        int ret;

        if (!drm_core_check_feature(dev, DRIVER_HAVE_DMA))
                return -EINVAL;

#if __OS_HAS_AGP
        if (request->flags & _DRM_AGP_BUFFER)
                ret = drm_addbufs_agp(dev, request);
        else
#endif
        if (request->flags & _DRM_SG_BUFFER)
                ret = drm_addbufs_sg(dev, request);
        else if (request->flags & _DRM_FB_BUFFER)
                ret = drm_addbufs_fb(dev, request);
        else
                ret = drm_addbufs_pci(dev, request);

        return ret;
}

/**
 * Get information about the buffer mappings.
 *
 * This was originally mean for debugging purposes, or by a sophisticated
 * client library to determine how best to use the available buffers (e.g.,
 * large buffers can be used for image transfer).
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg pointer to a drm_buf_info structure.
 * \return zero on success or a negative number on failure.
 *
 * Increments drm_device::buf_use while holding the drm_device::count_lock
 * lock, preventing of allocating more buffers after this call. Information
 * about each requested buffer is then copied into user space.
 */
int drm_infobufs(struct drm_device *dev, void *data,
                 struct drm_file *file_priv)
{
        struct drm_device_dma *dma = dev->dma;
        struct drm_buf_info *request = data;
        int i;
        int count;

        if (!drm_core_check_feature(dev, DRIVER_HAVE_DMA))
                return -EINVAL;

        if (!dma)
                return -EINVAL;

        spin_lock(&dev->count_lock);
        if (atomic_read(&dev->buf_alloc)) {
                spin_unlock(&dev->count_lock);
                return -EBUSY;
        }
        ++dev->buf_use;         /* Can't allocate more after this call */
        spin_unlock(&dev->count_lock);

        for (i = 0, count = 0; i < DRM_MAX_ORDER + 1; i++) {
                if (dma->bufs[i].buf_count)
                        ++count;
        }

        DRM_DEBUG("count = %d\n", count);

        if (request->count >= count) {
                for (i = 0, count = 0; i < DRM_MAX_ORDER + 1; i++) {
                        if (dma->bufs[i].buf_count) {
                                struct drm_buf_desc __user *to =
                                    &request->list[count];
                                struct drm_buf_entry *from = &dma->bufs[i];
                                struct drm_freelist *list = &dma->bufs[i].freelist;
                                if (copy_to_user(&to->count,
                                                 &from->buf_count,
                                                 sizeof(from->buf_count)) ||
                                    copy_to_user(&to->size,
                                                 &from->buf_size,
                                                 sizeof(from->buf_size)) ||
                                    copy_to_user(&to->low_mark,
                                                 &list->low_mark,
                                                 sizeof(list->low_mark)) ||
                                    copy_to_user(&to->high_mark,
                                                 &list->high_mark,
                                                 sizeof(list->high_mark)))
                                        return -EFAULT;

                                DRM_DEBUG("%d %d %d %d %d\n",
                                          i,
                                          dma->bufs[i].buf_count,
                                          dma->bufs[i].buf_size,
                                          dma->bufs[i].freelist.low_mark,
                                          dma->bufs[i].freelist.high_mark);
                                ++count;
                        }
                }
        }
        request->count = count;

        return 0;
}

/**
 * Specifies a low and high water mark for buffer allocation
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg a pointer to a drm_buf_desc structure.
 * \return zero on success or a negative number on failure.
 *
 * Verifies that the size order is bounded between the admissible orders and
 * updates the respective drm_device_dma::bufs entry low and high water mark.
 *
 * \note This ioctl is deprecated and mostly never used.
 */
int drm_markbufs(struct drm_device *dev, void *data,
                 struct drm_file *file_priv)
{
        struct drm_device_dma *dma = dev->dma;
        struct drm_buf_desc *request = data;
        int order;
        struct drm_buf_entry *entry;

        if (!drm_core_check_feature(dev, DRIVER_HAVE_DMA))
                return -EINVAL;

        if (!dma)
                return -EINVAL;

        DRM_DEBUG("%d, %d, %d\n",
                  request->size, request->low_mark, request->high_mark);
        order = drm_order(request->size);
        if (order < DRM_MIN_ORDER || order > DRM_MAX_ORDER)
                return -EINVAL;
        entry = &dma->bufs[order];

        if (request->low_mark < 0 || request->low_mark > entry->buf_count)
                return -EINVAL;
        if (request->high_mark < 0 || request->high_mark > entry->buf_count)
                return -EINVAL;

        entry->freelist.low_mark = request->low_mark;
        entry->freelist.high_mark = request->high_mark;

        return 0;
}

/**
 * Unreserve the buffers in list, previously reserved using drmDMA.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg pointer to a drm_buf_free structure.
 * \return zero on success or a negative number on failure.
 *
 * Calls free_buffer() for each used buffer.
 * This function is primarily used for debugging.
 */
int drm_freebufs(struct drm_device *dev, void *data,
                 struct drm_file *file_priv)
{
        struct drm_device_dma *dma = dev->dma;
        struct drm_buf_free *request = data;
        int i;
        int idx;
        struct drm_buf *buf;

        if (!drm_core_check_feature(dev, DRIVER_HAVE_DMA))
                return -EINVAL;

        if (!dma)
                return -EINVAL;

        DRM_DEBUG("%d\n", request->count);
        for (i = 0; i < request->count; i++) {
                if (copy_from_user(&idx, &request->list[i], sizeof(idx)))
                        return -EFAULT;
                if (idx < 0 || idx >= dma->buf_count) {
                        DRM_ERROR("Index %d (of %d max)\n",
                                  idx, dma->buf_count - 1);
                        return -EINVAL;
                }
                buf = dma->buflist[idx];
                if (buf->file_priv != file_priv) {
                        DRM_ERROR("Process %d freeing buffer not owned\n",
                                  task_pid_nr(current));
                        return -EINVAL;
                }
                drm_free_buffer(dev, buf);
        }

        return 0;
}

/**
 * Maps all of the DMA buffers into client-virtual space (ioctl).
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg pointer to a drm_buf_map structure.
 * \return zero on success or a negative number on failure.
 *
 * Maps the AGP, SG or PCI buffer region with do_mmap(), and copies information
 * about each buffer into user space. For PCI buffers, it calls do_mmap() with
 * offset equal to 0, which drm_mmap() interpretes as PCI buffers and calls
 * drm_mmap_dma().
 */
int drm_mapbufs(struct drm_device *dev, void *data,
                struct drm_file *file_priv)
{
        struct drm_device_dma *dma = dev->dma;
        int retcode = 0;
        const int zero = 0;
        unsigned long virtual;
        unsigned long address;
        struct drm_buf_map *request = data;
        int i;

        if (!drm_core_check_feature(dev, DRIVER_HAVE_DMA))
                return -EINVAL;

        if (!dma)
                return -EINVAL;

        spin_lock(&dev->count_lock);
        if (atomic_read(&dev->buf_alloc)) {
                spin_unlock(&dev->count_lock);
                return -EBUSY;
        }
        dev->buf_use++;         /* Can't allocate more after this call */
        spin_unlock(&dev->count_lock);

        if (request->count >= dma->buf_count) {
                if ((drm_core_has_AGP(dev) && (dma->flags & _DRM_DMA_USE_AGP))
                    || (drm_core_check_feature(dev, DRIVER_SG)
                        && (dma->flags & _DRM_DMA_USE_SG))
                    || (drm_core_check_feature(dev, DRIVER_FB_DMA)
                        && (dma->flags & _DRM_DMA_USE_FB))) {
                        struct drm_local_map *map = dev->agp_buffer_map;
                        unsigned long token = dev->agp_buffer_token;

                        if (!map) {
                                retcode = -EINVAL;
                                goto done;
                        }
                        down_write(&current->mm->mmap_sem);
                        virtual = do_mmap(file_priv->filp, 0, map->size,
                                          PROT_READ | PROT_WRITE,
                                          MAP_SHARED,
                                          token);
                        up_write(&current->mm->mmap_sem);
                } else {
                        down_write(&current->mm->mmap_sem);
                        virtual = do_mmap(file_priv->filp, 0, dma->byte_count,
                                          PROT_READ | PROT_WRITE,
                                          MAP_SHARED, 0);
                        up_write(&current->mm->mmap_sem);
                }
                if (virtual > -1024UL) {
                        /* Real error */
                        retcode = (signed long)virtual;
                        goto done;
                }
                request->virtual = (void __user *)virtual;

                for (i = 0; i < dma->buf_count; i++) {
                        if (copy_to_user(&request->list[i].idx,
                                         &dma->buflist[i]->idx,
                                         sizeof(request->list[0].idx))) {
                                retcode = -EFAULT;
                                goto done;
                        }
                        if (copy_to_user(&request->list[i].total,
                                         &dma->buflist[i]->total,
                                         sizeof(request->list[0].total))) {
                                retcode = -EFAULT;
                                goto done;
                        }
                        if (copy_to_user(&request->list[i].used,
                                         &zero, sizeof(zero))) {
                                retcode = -EFAULT;
                                goto done;
                        }
                        address = virtual + dma->buflist[i]->offset;    /* *** */
                        if (copy_to_user(&request->list[i].address,
                                         &address, sizeof(address))) {
                                retcode = -EFAULT;
                                goto done;
                        }
                }
        }
      done:
        request->count = dma->buf_count;
        DRM_DEBUG("%d buffers, retcode = %d\n", request->count, retcode);

        return retcode;
}

/**
 * Compute size order.  Returns the exponent of the smaller power of two which
 * is greater or equal to given number.
 *
 * \param size size.
 * \return order.
 *
 * \todo Can be made faster.
 */
int drm_order(unsigned long size)
{
        int order;
        unsigned long tmp;

        for (order = 0, tmp = size >> 1; tmp; tmp >>= 1, order++) ;

        if (size & (size - 1))
                ++order;

        return order;
}
EXPORT_SYMBOL(drm_order);