[linux-2.6-block.git] / arch / c6x / mm / dma-coherent.c

/*
 *  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 *c6x_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
		gfp_t gfp, unsigned long attrs)
{
	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);
}

/*
 * Free DMA coherent memory as defined by the above mapping.
 */
void c6x_dma_free(struct device *dev, size_t size, void *vaddr,
		dma_addr_t dma_handle, unsigned long attrs)
{
	int order;

	if (!dma_size || !size)
		return;

	order = get_count_order(((size - 1) >> PAGE_SHIFT) + 1);

	__free_dma_pages(virt_to_phys(vaddr), order);
}

/*
 * 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);
}
Commit	Line	Data
14aa7e8b AJ	1	/*
	2	* Port on Texas Instruments TMS320C6x architecture
	3	*
	4	* Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
	5	* Author: Aurelien Jacquiot <aurelien.jacquiot@ti.com>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*
	11	* DMA uncached mapping support.
	12	*
	13	* Using code pulled from ARM
	14	* Copyright (C) 2000-2004 Russell King
	15	*
	16	*/
	17	#include <linux/slab.h>
	18	#include <linux/bitmap.h>
	19	#include <linux/bitops.h>
	20	#include <linux/module.h>
	21	#include <linux/interrupt.h>
	22	#include <linux/dma-mapping.h>
	23	#include <linux/memblock.h>
	24
	25	#include <asm/page.h>
	26
	27	/*
	28	* DMA coherent memory management, can be redefined using the memdma=
	29	* kernel command line
	30	*/
	31
	32	/* none by default */
	33	static phys_addr_t dma_base;
	34	static u32 dma_size;
	35	static u32 dma_pages;
	36
	37	static unsigned long *dma_bitmap;
	38
	39	/* bitmap lock */
	40	static DEFINE_SPINLOCK(dma_lock);
	41
	42	/*
	43	* Return a DMA coherent and contiguous memory chunk from the DMA memory
	44	*/
	45	static inline u32 __alloc_dma_pages(int order)
	46	{
	47	unsigned long flags;
	48	u32 pos;
	49
	50	spin_lock_irqsave(&dma_lock, flags);
	51	pos = bitmap_find_free_region(dma_bitmap, dma_pages, order);
	52	spin_unlock_irqrestore(&dma_lock, flags);
	53
	54	return dma_base + (pos << PAGE_SHIFT);
	55	}
	56
	57	static void __free_dma_pages(u32 addr, int order)
	58	{
	59	unsigned long flags;
	60	u32 pos = (addr - dma_base) >> PAGE_SHIFT;
	61
	62	if (addr < dma_base \|\| (pos + (1 << order)) >= dma_pages) {
	63	printk(KERN_ERR "%s: freeing outside range.\n", __func__);
	64	BUG();
65	}
66
67	spin_lock_irqsave(&dma_lock, flags);
68	bitmap_release_region(dma_bitmap, pos, order);
69	spin_unlock_irqrestore(&dma_lock, flags);
70	}
71
72	/*
73	* Allocate DMA coherent memory space and return both the kernel
74	* virtual and DMA address for that space.
75	*/
4605f04b	76	void c6x_dma_alloc(struct device dev, size_t size, dma_addr_t *handle,
00085f1e	77	gfp_t gfp, unsigned long attrs)
14aa7e8b AJ	78	{
	79	u32 paddr;
	80	int order;
	81
	82	if (!dma_size \|\| !size)
	83	return NULL;
	84
	85	order = get_count_order(((size - 1) >> PAGE_SHIFT) + 1);
	86
	87	paddr = __alloc_dma_pages(order);
	88
	89	if (handle)
	90	*handle = paddr;
	91
	92	if (!paddr)
	93	return NULL;
	94
	95	return phys_to_virt(paddr);
	96	}
14aa7e8b AJ	97
	98	/*
	99	* Free DMA coherent memory as defined by the above mapping.
	100	*/
4605f04b	101	void c6x_dma_free(struct device dev, size_t size, void vaddr,
00085f1e	102	dma_addr_t dma_handle, unsigned long attrs)
14aa7e8b AJ	103	{
	104	int order;
	105
	106	if (!dma_size \|\| !size)
	107	return;
	108
	109	order = get_count_order(((size - 1) >> PAGE_SHIFT) + 1);
	110
	111	__free_dma_pages(virt_to_phys(vaddr), order);
	112	}
14aa7e8b AJ	113
	114	/*
	115	* Initialise the coherent DMA memory allocator using the given uncached region.
	116	*/
	117	void __init coherent_mem_init(phys_addr_t start, u32 size)
	118	{
	119	phys_addr_t bitmap_phys;
	120
	121	if (!size)
	122	return;
	123
	124	printk(KERN_INFO
	125	"Coherent memory (DMA) region start=0x%x size=0x%x\n",
	126	start, size);
	127
	128	dma_base = start;
	129	dma_size = size;
	130
	131	/* allocate bitmap */
	132	dma_pages = dma_size >> PAGE_SHIFT;
	133	if (dma_size & (PAGE_SIZE - 1))
	134	++dma_pages;
	135
	136	bitmap_phys = memblock_alloc(BITS_TO_LONGS(dma_pages) * sizeof(long),
	137	sizeof(long));
	138
	139	dma_bitmap = phys_to_virt(bitmap_phys);
	140	memset(dma_bitmap, 0, dma_pages * PAGE_SIZE);
	141	}