text: /*
   * drivers/gpu/ion/ion_chunk_heap.c
   *
   * Copyright (C) 2012 Google, Inc.
   *
   * This software is licensed under the terms of the GNU General Public
   * License version 2, as published by the Free Software Foundation, and
   * may be copied, distributed, and modified under those terms.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   */
  //#include <linux/spinlock.h>
  #include <linux/dma-mapping.h>
  #include <linux/err.h>
  #include <linux/genalloc.h>
  #include <linux/io.h>
  #include <linux/ion.h>
  #include <linux/mm.h>
  #include <linux/scatterlist.h>
  #include <linux/slab.h>
  #include <linux/vmalloc.h>
  #include "ion_priv.h"
  
  #include <asm/mach/map.h>
  
  struct ion_chunk_heap {
  	struct ion_heap heap;
  	struct gen_pool *pool;
  	ion_phys_addr_t base;
  	unsigned long chunk_size;
  	unsigned long size;
  	unsigned long allocated;
  };
  
  static int ion_chunk_heap_allocate(struct ion_heap *heap,
  				      struct ion_buffer *buffer,
  				      unsigned long size, unsigned long align,
  				      unsigned long flags)
  {
  	struct ion_chunk_heap *chunk_heap =
  		container_of(heap, struct ion_chunk_heap, heap);
  	struct sg_table *table;
  	struct scatterlist *sg;
  	int ret, i;
  	unsigned long num_chunks;
  
  	if (ion_buffer_fault_user_mappings(buffer))
  		return -ENOMEM;
  
  	num_chunks = ALIGN(size, chunk_heap->chunk_size) /
  		chunk_heap->chunk_size;
  	buffer->size = num_chunks * chunk_heap->chunk_size;
  
  	if (buffer->size > chunk_heap->size - chunk_heap->allocated)
  		return -ENOMEM;
  
  	table = kzalloc(sizeof(struct sg_table), GFP_KERNEL);
  	if (!table)
  		return -ENOMEM;
  	ret = sg_alloc_table(table, num_chunks, GFP_KERNEL);
  	if (ret) {
  		kfree(table);
  		return ret;
  	}
  
  	sg = table->sgl;
  	for (i = 0; i < num_chunks; i++) {
  		unsigned long paddr = gen_pool_alloc(chunk_heap->pool,
  						     chunk_heap->chunk_size);
  		if (!paddr)
  			goto err;
  		sg_set_page(sg, phys_to_page(paddr), chunk_heap->chunk_size, 0);
  		sg = sg_next(sg);
  	}
  
  	buffer->priv_virt = table;
  	chunk_heap->allocated += buffer->size;
  	return 0;
  err:
  	sg = table->sgl;
  	for (i -= 1; i >= 0; i--) {
  		gen_pool_free(chunk_heap->pool, page_to_phys(sg_page(sg)),
  			      sg_dma_len(sg));
  		sg = sg_next(sg);
  	}
  	sg_free_table(table);
  	kfree(table);
  	return -ENOMEM;
  }
  
  static void ion_chunk_heap_free(struct ion_buffer *buffer)
  {
  	struct ion_heap *heap = buffer->heap;
  	struct ion_chunk_heap *chunk_heap =
  		container_of(heap, struct ion_chunk_heap, heap);
  	struct sg_table *table = buffer->priv_virt;
  	struct scatterlist *sg;
  	int i;
  
  	ion_heap_buffer_zero(buffer);
  
  	for_each_sg(table->sgl, sg, table->nents, i) {
  		if (ion_buffer_cached(buffer))
  			dma_sync_sg_for_device(NULL, sg, 1, DMA_BIDIRECTIONAL);
  		gen_pool_free(chunk_heap->pool, page_to_phys(sg_page(sg)),
  			      sg_dma_len(sg));
  	}
  	chunk_heap->allocated -= buffer->size;
  	sg_free_table(table);
  	kfree(table);
  }
  
  struct sg_table *ion_chunk_heap_map_dma(struct ion_heap *heap,
  					 struct ion_buffer *buffer)
  {
  	return buffer->priv_virt;
  }
  
  void ion_chunk_heap_unmap_dma(struct ion_heap *heap,
  			       struct ion_buffer *buffer)
  {
  	return;
  }
  
  static struct ion_heap_ops chunk_heap_ops = {
  	.allocate = ion_chunk_heap_allocate,
  	.free = ion_chunk_heap_free,
  	.map_dma = ion_chunk_heap_map_dma,
  	.unmap_dma = ion_chunk_heap_unmap_dma,
  	.map_user = ion_heap_map_user,
  	.map_kernel = ion_heap_map_kernel,
  	.unmap_kernel = ion_heap_unmap_kernel,
  };
  
  struct ion_heap *ion_chunk_heap_create(struct ion_platform_heap *heap_data)
  {
  	struct ion_chunk_heap *chunk_heap;
  	struct scatterlist sg;
  
  	chunk_heap = kzalloc(sizeof(struct ion_chunk_heap), GFP_KERNEL);
  	if (!chunk_heap)
  		return ERR_PTR(-ENOMEM);
  
  	chunk_heap->chunk_size = (unsigned long)heap_data->priv;
  	chunk_heap->pool = gen_pool_create(get_order(chunk_heap->chunk_size) +
  					   PAGE_SHIFT, -1);
  	if (!chunk_heap->pool) {
  		kfree(chunk_heap);
  		return ERR_PTR(-ENOMEM);
  	}
  	chunk_heap->base = heap_data->base;
  	chunk_heap->size = heap_data->size;
  	chunk_heap->allocated = 0;
  
  	sg_init_table(&sg, 1);
  	sg_set_page(&sg, phys_to_page(heap_data->base), heap_data->size, 0);
  	dma_sync_sg_for_device(NULL, &sg, 1, DMA_BIDIRECTIONAL);
  	gen_pool_add(chunk_heap->pool, chunk_heap->base, heap_data->size, -1);
  	chunk_heap->heap.ops = &chunk_heap_ops;
  	chunk_heap->heap.type = ION_HEAP_TYPE_CHUNK;
  	chunk_heap->heap.flags = ION_HEAP_FLAG_DEFER_FREE;
  	pr_info("%s: base %pa size %zd align %pa\n", __func__,
  		&chunk_heap->base, heap_data->size, &heap_data->align);
  
  	return &chunk_heap->heap;
  }
  
  void ion_chunk_heap_destroy(struct ion_heap *heap)
  {
  	struct ion_chunk_heap *chunk_heap =
  	     container_of(heap, struct  ion_chunk_heap, heap);
  
  	gen_pool_destroy(chunk_heap->pool);
  	kfree(chunk_heap);
  	chunk_heap = NULL;
  }
  