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drm_scatter.c

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/**
 * \file drm_scatter.c
 * IOCTLs to manage scatter/gather memory
 *
 * \author Gareth Hughes <gareth@valinux.com>
 */

/*
 * Created: Mon Dec 18 23:20:54 2000 by gareth@valinux.com
 *
 * 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.
 */

#include <linux/vmalloc.h>
#include "drmP.h"

#define DEBUG_SCATTER 0

void drm_sg_cleanup(struct drm_sg_mem * entry)
{
      struct page *page;
      int i;

      for (i = 0; i < entry->pages; i++) {
            page = entry->pagelist[i];
            if (page)
                  ClearPageReserved(page);
      }

      vfree(entry->virtual);

      drm_free(entry->busaddr,
             entry->pages * sizeof(*entry->busaddr), DRM_MEM_PAGES);
      drm_free(entry->pagelist,
             entry->pages * sizeof(*entry->pagelist), DRM_MEM_PAGES);
      drm_free(entry, sizeof(*entry), DRM_MEM_SGLISTS);
}

#ifdef _LP64
# define ScatterHandle(x) (unsigned int)((x >> 32) + (x & ((1L << 32) - 1)))
#else
# define ScatterHandle(x) (unsigned int)(x)
#endif

int drm_sg_alloc(struct drm_device *dev, struct drm_scatter_gather * request)
{
      struct drm_sg_mem *entry;
      unsigned long pages, i, j;

      DRM_DEBUG("%s\n", __FUNCTION__);

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

      if (dev->sg)
            return -EINVAL;

      entry = drm_alloc(sizeof(*entry), DRM_MEM_SGLISTS);
      if (!entry)
            return -ENOMEM;

      memset(entry, 0, sizeof(*entry));
      pages = (request->size + PAGE_SIZE - 1) / PAGE_SIZE;
      DRM_DEBUG("sg size=%ld pages=%ld\n", request->size, pages);

      entry->pages = pages;
      entry->pagelist = drm_alloc(pages * sizeof(*entry->pagelist),
                            DRM_MEM_PAGES);
      if (!entry->pagelist) {
            drm_free(entry, sizeof(*entry), DRM_MEM_SGLISTS);
            return -ENOMEM;
      }

      memset(entry->pagelist, 0, pages * sizeof(*entry->pagelist));

      entry->busaddr = drm_alloc(pages * sizeof(*entry->busaddr),
                           DRM_MEM_PAGES);
      if (!entry->busaddr) {
            drm_free(entry->pagelist,
                   entry->pages * sizeof(*entry->pagelist),
                   DRM_MEM_PAGES);
            drm_free(entry, sizeof(*entry), DRM_MEM_SGLISTS);
            return -ENOMEM;
      }
      memset((void *)entry->busaddr, 0, pages * sizeof(*entry->busaddr));

      entry->virtual = vmalloc_32(pages << PAGE_SHIFT);
      if (!entry->virtual) {
            drm_free(entry->busaddr,
                   entry->pages * sizeof(*entry->busaddr), DRM_MEM_PAGES);
            drm_free(entry->pagelist,
                   entry->pages * sizeof(*entry->pagelist),
                   DRM_MEM_PAGES);
            drm_free(entry, sizeof(*entry), DRM_MEM_SGLISTS);
            return -ENOMEM;
      }

      /* This also forces the mapping of COW pages, so our page list
       * will be valid.  Please don't remove it...
       */
      memset(entry->virtual, 0, pages << PAGE_SHIFT);

      entry->handle = ScatterHandle((unsigned long)entry->virtual);

      DRM_DEBUG("sg alloc handle  = %08lx\n", entry->handle);
      DRM_DEBUG("sg alloc virtual = %p\n", entry->virtual);

      for (i = (unsigned long)entry->virtual, j = 0; j < pages;
           i += PAGE_SIZE, j++) {
            entry->pagelist[j] = vmalloc_to_page((void *)i);
            if (!entry->pagelist[j])
                  goto failed;
            SetPageReserved(entry->pagelist[j]);
      }

      request->handle = entry->handle;

      dev->sg = entry;

#if DEBUG_SCATTER
      /* Verify that each page points to its virtual address, and vice
       * versa.
       */
      {
            int error = 0;

            for (i = 0; i < pages; i++) {
                  unsigned long *tmp;

                  tmp = page_address(entry->pagelist[i]);
                  for (j = 0;
                       j < PAGE_SIZE / sizeof(unsigned long);
                       j++, tmp++) {
                        *tmp = 0xcafebabe;
                  }
                  tmp = (unsigned long *)((u8 *) entry->virtual +
                                    (PAGE_SIZE * i));
                  for (j = 0;
                       j < PAGE_SIZE / sizeof(unsigned long);
                       j++, tmp++) {
                        if (*tmp != 0xcafebabe && error == 0) {
                              error = 1;
                              DRM_ERROR("Scatter allocation error, "
                                      "pagelist does not match "
                                      "virtual mapping\n");
                        }
                  }
                  tmp = page_address(entry->pagelist[i]);
                  for (j = 0;
                       j < PAGE_SIZE / sizeof(unsigned long);
                       j++, tmp++) {
                        *tmp = 0;
                  }
            }
            if (error == 0)
                  DRM_ERROR("Scatter allocation matches pagelist\n");
      }
#endif

      return 0;

      failed:
      drm_sg_cleanup(entry);
      return -ENOMEM;
}
EXPORT_SYMBOL(drm_sg_alloc);


int drm_sg_alloc_ioctl(struct drm_device *dev, void *data,
                   struct drm_file *file_priv)
{
      struct drm_scatter_gather *request = data;

      return drm_sg_alloc(dev, request);

}

int drm_sg_free(struct drm_device *dev, void *data,
            struct drm_file *file_priv)
{
      struct drm_scatter_gather *request = data;
      struct drm_sg_mem *entry;

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

      entry = dev->sg;
      dev->sg = NULL;

      if (!entry || entry->handle != request->handle)
            return -EINVAL;

      DRM_DEBUG("sg free virtual  = %p\n", entry->virtual);

      drm_sg_cleanup(entry);

      return 0;
}

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