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/*
* Port on Texas Instruments TMS320C6x architecture
*
* Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
* Author: Aurelien Jacquiot <aurelien.jacquiot@ti.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* DMA uncached mapping support.
*
* Using code pulled from ARM
* Copyright (C) 2000-2004 Russell King
*
*/
#include <linux/slab.h>
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/memblock.h>
#include <asm/page.h>
/*
* DMA coherent memory management, can be redefined using the memdma=
* kernel command line
*/
/* none by default */
static phys_addr_t dma_base;
static u32 dma_size;
static u32 dma_pages;
static unsigned long *dma_bitmap;
/* bitmap lock */
static DEFINE_SPINLOCK(dma_lock);
/*
* Return a DMA coherent and contiguous memory chunk from the DMA memory
*/
static inline u32 __alloc_dma_pages(int order)
{
unsigned long flags;
u32 pos;
spin_lock_irqsave(&dma_lock, flags);
pos = bitmap_find_free_region(dma_bitmap, dma_pages, order);
spin_unlock_irqrestore(&dma_lock, flags);
return dma_base + (pos << PAGE_SHIFT);
}
static void __free_dma_pages(u32 addr, int order)
{
unsigned long flags;
u32 pos = (addr - dma_base) >> PAGE_SHIFT;
if (addr < dma_base || (pos + (1 << order)) >= dma_pages) {
printk(KERN_ERR "%s: freeing outside range.\n", __func__);
BUG();
}
spin_lock_irqsave(&dma_lock, flags);
bitmap_release_region(dma_bitmap, pos, order);
spin_unlock_irqrestore(&dma_lock, flags);
}
/*
* Allocate DMA coherent memory space and return both the kernel
* virtual and DMA address for that space.
*/
void *dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *handle, gfp_t gfp)
{
u32 paddr;
int order;
if (!dma_size || !size)
return NULL;
order = get_count_order(((size - 1) >> PAGE_SHIFT) + 1);
paddr = __alloc_dma_pages(order);
if (handle)
*handle = paddr;
if (!paddr)
return NULL;
return phys_to_virt(paddr);
}
EXPORT_SYMBOL(dma_alloc_coherent);
/*
* Free DMA coherent memory as defined by the above mapping.
*/
void dma_free_coherent(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_handle)
{
int order;
if (!dma_size || !size)
return;
order = get_count_order(((size - 1) >> PAGE_SHIFT) + 1);
__free_dma_pages(virt_to_phys(vaddr), order);
}
EXPORT_SYMBOL(dma_free_coherent);
/*
* Initialise the coherent DMA memory allocator using the given uncached region.
*/
void __init coherent_mem_init(phys_addr_t start, u32 size)
{
phys_addr_t bitmap_phys;
if (!size)
return;
printk(KERN_INFO
"Coherent memory (DMA) region start=0x%x size=0x%x\n",
start, size);
dma_base = start;
dma_size = size;
/* allocate bitmap */
dma_pages = dma_size >> PAGE_SHIFT;
if (dma_size & (PAGE_SIZE - 1))
++dma_pages;
bitmap_phys = memblock_alloc(BITS_TO_LONGS(dma_pages) * sizeof(long),
sizeof(long));
dma_bitmap = phys_to_virt(bitmap_phys);
memset(dma_bitmap, 0, dma_pages * PAGE_SIZE);
}
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