/*
 * drivers/staging/android/ion/ion_system_heap.c
 *
 * Copyright (C) 2011 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 <asm/page.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/highmem.h>
#include <linux/mm.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include "ion.h"
#include "ion_priv.h"

struct page_info {
	struct page *page;
	unsigned long order;
	struct list_head list;
};

static unsigned int orders[] = {8, 4, 0};

static struct page_info *alloc_largest_available(unsigned long size,
						 bool split_pages,
						 unsigned int max_order)
{
	struct page *page;
	struct page_info *info;
	int i;

	for (i = 0; i < ARRAY_SIZE(orders); i++) {
		if (size < (1 << orders[i]) * PAGE_SIZE)
			continue;
		if (max_order < orders[i])
			continue;
		page = alloc_pages(GFP_HIGHUSER | __GFP_ZERO |
				   __GFP_NOWARN | __GFP_NORETRY, orders[i]);
		if (!page)
			continue;
		if (split_pages)
			split_page(page, orders[i]);
		info = kmalloc(sizeof(struct page_info *), GFP_KERNEL);
		info->page = page;
		info->order = orders[i];
		return info;
	}
	return NULL;
}

static int ion_system_heap_allocate(struct ion_heap *heap,
				     struct ion_buffer *buffer,
				     unsigned long size, unsigned long align,
				     unsigned long flags)
{
	struct sg_table *table;
	struct scatterlist *sg;
	int ret;
	struct list_head pages;
	struct page_info *info, *tmp_info;
	int i = 0;
	long size_remaining = PAGE_ALIGN(size);
	bool split_pages = ion_buffer_fault_user_mappings(buffer);


	unsigned int max_order = orders[0];

	INIT_LIST_HEAD(&pages);
	while (size_remaining > 0) {
		info = alloc_largest_available(size_remaining, split_pages,
					       max_order);
		if (!info)
			goto err;
		list_add_tail(&info->list, &pages);
		size_remaining -= (1 << info->order) * PAGE_SIZE;
		max_order = info->order;
		i++;
	}

	table = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
	if (!table)
		goto err;

	if (split_pages)
		ret = sg_alloc_table(table, PAGE_ALIGN(size) / PAGE_SIZE,
				     GFP_KERNEL);
	else
		ret = sg_alloc_table(table, i, GFP_KERNEL);

	if (ret)
		goto err1;

	sg = table->sgl;
	list_for_each_entry_safe(info, tmp_info, &pages, list) {
		struct page *page = info->page;

		if (split_pages) {
			for (i = 0; i < (1 << info->order); i++) {
				sg_set_page(sg, page + i, PAGE_SIZE, 0);
				sg = sg_next(sg);
			}
		} else {
			sg_set_page(sg, page, (1 << info->order) * PAGE_SIZE,
				    0);
			sg = sg_next(sg);
		}
		list_del(&info->list);
		kfree(info);
	}

	dma_sync_sg_for_device(NULL, table->sgl, table->nents,
			       DMA_BIDIRECTIONAL);

	buffer->priv_virt = table;
	return 0;
err1:
	kfree(table);
err:
	list_for_each_entry(info, &pages, list) {
		if (split_pages)
			for (i = 0; i < (1 << info->order); i++)
				__free_page(info->page + i);
		else
			__free_pages(info->page, info->order);

		kfree(info);
	}
	return -ENOMEM;
}

void ion_system_heap_free(struct ion_buffer *buffer)
{
	int i;
	struct scatterlist *sg;
	struct sg_table *table = buffer->priv_virt;

	for_each_sg(table->sgl, sg, table->nents, i)
		__free_pages(sg_page(sg), get_order(sg_dma_len(sg)));
	if (buffer->sg_table)
		sg_free_table(buffer->sg_table);
	kfree(buffer->sg_table);
}

struct sg_table *ion_system_heap_map_dma(struct ion_heap *heap,
					 struct ion_buffer *buffer)
{
	return buffer->priv_virt;
}

void ion_system_heap_unmap_dma(struct ion_heap *heap,
			       struct ion_buffer *buffer)
{
	return;
}

void *ion_system_heap_map_kernel(struct ion_heap *heap,
				 struct ion_buffer *buffer)
{
	struct scatterlist *sg;
	int i, j;
	void *vaddr;
	pgprot_t pgprot;
	struct sg_table *table = buffer->priv_virt;
	int npages = PAGE_ALIGN(buffer->size) / PAGE_SIZE;
	struct page **pages = kzalloc(sizeof(struct page *) * npages,
				     GFP_KERNEL);
	struct page **tmp = pages;

	if (buffer->flags & ION_FLAG_CACHED)
		pgprot = PAGE_KERNEL;
	else
		pgprot = pgprot_writecombine(PAGE_KERNEL);

	for_each_sg(table->sgl, sg, table->nents, i) {
		int npages_this_entry = PAGE_ALIGN(sg_dma_len(sg)) / PAGE_SIZE;
		struct page *page = sg_page(sg);
		BUG_ON(i >= npages);
		for (j = 0; j < npages_this_entry; j++) {
			*(tmp++) = page++;
		}
	}
	vaddr = vmap(pages, npages, VM_MAP, pgprot);
	kfree(pages);

	return vaddr;
}

void ion_system_heap_unmap_kernel(struct ion_heap *heap,
				  struct ion_buffer *buffer)
{
	vunmap(buffer->vaddr);
}

int ion_system_heap_map_user(struct ion_heap *heap, struct ion_buffer *buffer,
			     struct vm_area_struct *vma)
{
	struct sg_table *table = buffer->priv_virt;
	unsigned long addr = vma->vm_start;
	unsigned long offset = vma->vm_pgoff;
	struct scatterlist *sg;
	int i;

	for_each_sg(table->sgl, sg, table->nents, i) {
		if (offset) {
			offset--;
			continue;
		}
		remap_pfn_range(vma, addr, page_to_pfn(sg_page(sg)),
				sg_dma_len(sg), vma->vm_page_prot);
		addr += sg_dma_len(sg);
		if (addr >= vma->vm_end)
			return 0;
	}
	return 0;
}

static struct ion_heap_ops vmalloc_ops = {
	.allocate = ion_system_heap_allocate,
	.free = ion_system_heap_free,
	.map_dma = ion_system_heap_map_dma,
	.unmap_dma = ion_system_heap_unmap_dma,
	.map_kernel = ion_system_heap_map_kernel,
	.unmap_kernel = ion_system_heap_unmap_kernel,
	.map_user = ion_system_heap_map_user,
};

struct ion_heap *ion_system_heap_create(struct ion_platform_heap *unused)
{
	struct ion_heap *heap;

	heap = kzalloc(sizeof(struct ion_heap), GFP_KERNEL);
	if (!heap)
		return ERR_PTR(-ENOMEM);
	heap->ops = &vmalloc_ops;
	heap->type = ION_HEAP_TYPE_SYSTEM;
	return heap;
}

void ion_system_heap_destroy(struct ion_heap *heap)
{
	kfree(heap);
}

static int ion_system_contig_heap_allocate(struct ion_heap *heap,
					   struct ion_buffer *buffer,
					   unsigned long len,
					   unsigned long align,
					   unsigned long flags)
{
	buffer->priv_virt = kzalloc(len, GFP_KERNEL);
	if (!buffer->priv_virt)
		return -ENOMEM;
	return 0;
}

void ion_system_contig_heap_free(struct ion_buffer *buffer)
{
	kfree(buffer->priv_virt);
}

static int ion_system_contig_heap_phys(struct ion_heap *heap,
				       struct ion_buffer *buffer,
				       ion_phys_addr_t *addr, size_t *len)
{
	*addr = virt_to_phys(buffer->priv_virt);
	*len = buffer->size;
	return 0;
}

struct sg_table *ion_system_contig_heap_map_dma(struct ion_heap *heap,
						struct ion_buffer *buffer)
{
	struct sg_table *table;
	int ret;

	table = kzalloc(sizeof(struct sg_table), GFP_KERNEL);
	if (!table)
		return ERR_PTR(-ENOMEM);
	ret = sg_alloc_table(table, 1, GFP_KERNEL);
	if (ret) {
		kfree(table);
		return ERR_PTR(ret);
	}
	sg_set_page(table->sgl, virt_to_page(buffer->priv_virt), buffer->size,
		    0);
	return table;
}

void ion_system_contig_heap_unmap_dma(struct ion_heap *heap,
				      struct ion_buffer *buffer)
{
	sg_free_table(buffer->sg_table);
	kfree(buffer->sg_table);
}

int ion_system_contig_heap_map_user(struct ion_heap *heap,
				    struct ion_buffer *buffer,
				    struct vm_area_struct *vma)
{
	unsigned long pfn = __phys_to_pfn(virt_to_phys(buffer->priv_virt));
	return remap_pfn_range(vma, vma->vm_start, pfn + vma->vm_pgoff,
			       vma->vm_end - vma->vm_start,
			       vma->vm_page_prot);

}

static struct ion_heap_ops kmalloc_ops = {
	.allocate = ion_system_contig_heap_allocate,
	.free = ion_system_contig_heap_free,
	.phys = ion_system_contig_heap_phys,
	.map_dma = ion_system_contig_heap_map_dma,
	.unmap_dma = ion_system_contig_heap_unmap_dma,
	.map_kernel = ion_system_heap_map_kernel,
	.unmap_kernel = ion_system_heap_unmap_kernel,
	.map_user = ion_system_contig_heap_map_user,
};

struct ion_heap *ion_system_contig_heap_create(struct ion_platform_heap *unused)
{
	struct ion_heap *heap;

	heap = kzalloc(sizeof(struct ion_heap), GFP_KERNEL);
	if (!heap)
		return ERR_PTR(-ENOMEM);
	heap->ops = &kmalloc_ops;
	heap->type = ION_HEAP_TYPE_SYSTEM_CONTIG;
	return heap;
}

void ion_system_contig_heap_destroy(struct ion_heap *heap)
{
	kfree(heap);
}