/*

   * \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/mm.h>

  #include <linux/slab.h>

  #include <linux/vmalloc.h>
  
  #include <drm/drm.h>
  #include <drm/drm_drv.h>
  #include <drm/drm_print.h>

  #include "drm_legacy.h"

  
  #define DEBUG_SCATTER 0

  static 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);

  	kfree(entry->busaddr);
  	kfree(entry->pagelist);
  	kfree(entry);

  }

  void drm_legacy_sg_cleanup(struct drm_device *dev)
  {
  	if (drm_core_check_feature(dev, DRIVER_SG) && dev->sg &&

  	    drm_core_check_feature(dev, DRIVER_LEGACY)) {

  		drm_sg_cleanup(dev->sg);
  		dev->sg = NULL;
  	}
  }

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

  int drm_legacy_sg_alloc(struct drm_device *dev, void *data,
  			struct drm_file *file_priv)

  {

  	struct drm_scatter_gather *request = data;

  	struct drm_sg_mem *entry;

  	unsigned long pages, i, j;

  	DRM_DEBUG("
  ");

  	if (!drm_core_check_feature(dev, DRIVER_LEGACY))

  		return -EOPNOTSUPP;

  	if (!drm_core_check_feature(dev, DRIVER_SG))

  		return -EOPNOTSUPP;

  	if (request->size > SIZE_MAX - PAGE_SIZE)
  		return -EINVAL;

  	if (dev->sg)

  		return -EINVAL;

  	entry = kzalloc(sizeof(*entry), GFP_KERNEL);

  	if (!entry)

  		return -ENOMEM;

  	pages = (request->size + PAGE_SIZE - 1) / PAGE_SIZE;

  	DRM_DEBUG("size=%ld pages=%ld
  ", request->size, pages);

  
  	entry->pages = pages;

  	entry->pagelist = kcalloc(pages, sizeof(*entry->pagelist), GFP_KERNEL);

  	if (!entry->pagelist) {

  		kfree(entry);

  		return -ENOMEM;
  	}

  	entry->busaddr = kcalloc(pages, sizeof(*entry->busaddr), GFP_KERNEL);

  	if (!entry->busaddr) {

  		kfree(entry->pagelist);
  		kfree(entry);

  		return -ENOMEM;
  	}

  	entry->virtual = vmalloc_32(pages << PAGE_SHIFT);

  	if (!entry->virtual) {

  		kfree(entry->busaddr);
  		kfree(entry->pagelist);
  		kfree(entry);

  		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("handle  = %08lx
  ", entry->handle);
  	DRM_DEBUG("virtual = %p
  ", 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
  ");
  				}
  			}
  			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
  ");

  	}
  #endif
  
  	return 0;

        failed:
  	drm_sg_cleanup(entry);

  	return -ENOMEM;
  }

  int drm_legacy_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_LEGACY))

  		return -EOPNOTSUPP;

  	if (!drm_core_check_feature(dev, DRIVER_SG))

  		return -EOPNOTSUPP;

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

  	if (!entry || entry->handle != request->handle)

  		return -EINVAL;

  	DRM_DEBUG("virtual  = %p
  ", entry->virtual);

  	drm_sg_cleanup(entry);

  
  	return 0;
  }