/*
 * drivers/gpu/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/ion.h>
#include <linux/mm.h>
#include <linux/scatterlist.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include "ion_priv.h"

static unsigned int high_order_gfp_flags = (GFP_HIGHUSER | __GFP_ZERO |
					    __GFP_NOWARN | __GFP_NORETRY |
					    __GFP_NO_KSWAPD) & ~__GFP_WAIT;
static unsigned int low_order_gfp_flags  = (GFP_HIGHUSER | __GFP_ZERO |
					 __GFP_NOWARN);
static const unsigned int orders[] = {8, 4, 0};
static const int num_orders = ARRAY_SIZE(orders);
static int order_to_index(unsigned int order)
{
	int i;
	for (i = 0; i < num_orders; i++)
		if (order == orders[i])
			return i;
	BUG();
	return -1;
}

static unsigned int order_to_size(int order)
{
	return PAGE_SIZE << order;
}

struct ion_system_heap {
	struct ion_heap heap;
	struct ion_page_pool **pools;
};

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

static struct page *alloc_buffer_page(struct ion_system_heap *heap,
				      struct ion_buffer *buffer,
				      unsigned long order)
{
	bool cached = ion_buffer_cached(buffer);
	bool split_pages = ion_buffer_fault_user_mappings(buffer);
	struct ion_page_pool *pool = heap->pools[order_to_index(order)];
	struct page *page;

	if (!cached) {
		page = ion_page_pool_alloc(pool);
	} else {
		gfp_t gfp_flags = low_order_gfp_flags;

		if (order > 4)
			gfp_flags = high_order_gfp_flags;
		page = alloc_pages(gfp_flags, order);
		if (!page)
			return 0;
		__dma_page_cpu_to_dev(page, 0, PAGE_SIZE << order,
				      DMA_BIDIRECTIONAL);
	}
	if (!page)
		return 0;

	if (split_pages)
		split_page(page, order);
	return page;
}

static void free_buffer_page(struct ion_system_heap *heap,
			     struct ion_buffer *buffer, struct page *page,
			     unsigned int order)
{
	bool cached = ion_buffer_cached(buffer);
	bool split_pages = ion_buffer_fault_user_mappings(buffer);
	int i;

	if (!cached) {
		struct ion_page_pool *pool = heap->pools[order_to_index(order)];
		/* zero the pages before returning them to the pool for
		   security.  This uses vmap as we want to set the pgprot so
		   the writes to occur to noncached mappings, as the pool's
		   purpose is to keep the pages out of the cache */
		for (i = 0; i < (1 << order); i++) {
			struct page *sub_page = page + i;
			void *addr = vmap(&sub_page, 1, VM_MAP,
					  pgprot_writecombine(PAGE_KERNEL));
			memset(addr, 0, PAGE_SIZE);
			vunmap(addr);
		}
		ion_page_pool_free(pool, page);
	} else if (split_pages) {
		for (i = 0; i < (1 << order); i++)
			__free_page(page + i);
	} else {
		__free_pages(page, order);
	}
}


static struct page_info *alloc_largest_available(struct ion_system_heap *heap,
						 struct ion_buffer *buffer,
						 unsigned long size,
						 unsigned int max_order)
{
	struct page *page;
	struct page_info *info;
	int i;

	for (i = 0; i < num_orders; i++) {
		if (size < order_to_size(orders[i]))
			continue;
		if (max_order < orders[i])
			continue;

		page = alloc_buffer_page(heap, buffer, orders[i]);
		if (!page)
			continue;

		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 ion_system_heap *sys_heap = container_of(heap,
							struct ion_system_heap,
							heap);
	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);
	unsigned int max_order = orders[0];
	bool split_pages = ion_buffer_fault_user_mappings(buffer);

	INIT_LIST_HEAD(&pages);
	while (size_remaining > 0) {
		info = alloc_largest_available(sys_heap, buffer, size_remaining, 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);
	}

	buffer->priv_virt = table;
	return 0;
err1:
	kfree(table);
err:
	list_for_each_entry(info, &pages, list) {
		free_buffer_page(sys_heap, buffer, info->page, info->order);
		kfree(info);
	}
	return -ENOMEM;
}

void ion_system_heap_free(struct ion_buffer *buffer)
{
	struct ion_heap *heap = buffer->heap;
	struct ion_system_heap *sys_heap = container_of(heap,
							struct ion_system_heap,
							heap);
	struct sg_table *table = buffer->priv_virt;
	struct scatterlist *sg;
	LIST_HEAD(pages);
	int i;

	for_each_sg(table->sgl, sg, table->nents, i)
		free_buffer_page(sys_heap, buffer, sg_page(sg), get_order(sg_dma_len(sg)));
	sg_free_table(table);
	kfree(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 = vmalloc(sizeof(struct page *) * npages);
	struct page **tmp = pages;

	if (!pages)
		return 0;

	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);
	vfree(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 * PAGE_SIZE;
	struct scatterlist *sg;
	int i;

	for_each_sg(table->sgl, sg, table->nents, i) {
		struct page *page = sg_page(sg);
		unsigned long remainder = vma->vm_end - addr;
		unsigned long len = sg_dma_len(sg);

		if (offset >= sg_dma_len(sg)) {
			offset -= sg_dma_len(sg);
			continue;
		} else if (offset) {
			page += offset / PAGE_SIZE;
			len = sg_dma_len(sg) - offset;
			offset = 0;
		}
		len = min(len, remainder);
		remap_pfn_range(vma, addr, page_to_pfn(page), len,
				vma->vm_page_prot);
		addr += len;
		if (addr >= vma->vm_end)
			return 0;
	}
	return 0;
}

static struct ion_heap_ops system_heap_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,
};

static int ion_system_heap_debug_show(struct ion_heap *heap, struct seq_file *s,
				      void *unused)
{

	struct ion_system_heap *sys_heap = container_of(heap,
							struct ion_system_heap,
							heap);
	int i;
	for (i = 0; i < num_orders; i++) {
		struct ion_page_pool *pool = sys_heap->pools[i];
		seq_printf(s, "%d order %u highmem pages in pool = %lu total\n",
			   pool->high_count, pool->order,
			   (1 << pool->order) * PAGE_SIZE * pool->high_count);
		seq_printf(s, "%d order %u lowmem pages in pool = %lu total\n",
			   pool->low_count, pool->order,
			   (1 << pool->order) * PAGE_SIZE * pool->low_count);
	}
	return 0;
}

struct ion_heap *ion_system_heap_create(struct ion_platform_heap *unused)
{
	struct ion_system_heap *heap;
	int i;

	heap = kzalloc(sizeof(struct ion_system_heap), GFP_KERNEL);
	if (!heap)
		return ERR_PTR(-ENOMEM);
	heap->heap.ops = &system_heap_ops;
	heap->heap.type = ION_HEAP_TYPE_SYSTEM;
	heap->pools = kzalloc(sizeof(struct ion_page_pool *) * num_orders,
			      GFP_KERNEL);
	if (!heap->pools)
		goto err_alloc_pools;
	for (i = 0; i < num_orders; i++) {
		struct ion_page_pool *pool;
		gfp_t gfp_flags = low_order_gfp_flags;

		if (orders[i] > 4)
			gfp_flags = high_order_gfp_flags;
		pool = ion_page_pool_create(gfp_flags, orders[i]);
		if (!pool)
			goto err_create_pool;
		heap->pools[i] = pool;
	}
	heap->heap.debug_show = ion_system_heap_debug_show;
	return &heap->heap;
err_create_pool:
	for (i = 0; i < num_orders; i++)
		if (heap->pools[i])
			ion_page_pool_destroy(heap->pools[i]);
	kfree(heap->pools);
err_alloc_pools:
	kfree(heap);
	return ERR_PTR(-ENOMEM);
}

void ion_system_heap_destroy(struct ion_heap *heap)
{
	struct ion_system_heap *sys_heap = container_of(heap,
							struct ion_system_heap,
							heap);
	int i;

	for (i = 0; i < num_orders; i++)
		ion_page_pool_destroy(sys_heap->pools[i]);
	kfree(sys_heap->pools);
	kfree(sys_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);
}