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 */ 33static phys_addr_t dma_base; 34static u32 dma_size; 35static u32 dma_pages; 36 37static unsigned long *dma_bitmap; 38 39/* bitmap lock */ 40static DEFINE_SPINLOCK(dma_lock); 41 42/* 43 * Return a DMA coherent and contiguous memory chunk from the DMA memory 44 */ 45static 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 57static 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 */ 76void *dma_alloc_coherent(struct device *dev, size_t size, 77 dma_addr_t *handle, gfp_t gfp) 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} 97EXPORT_SYMBOL(dma_alloc_coherent); 98 99/* 100 * Free DMA coherent memory as defined by the above mapping. 101 */ 102void dma_free_coherent(struct device *dev, size_t size, void *vaddr, 103 dma_addr_t dma_handle) 104{ 105 int order; 106 107 if (!dma_size || !size) 108 return; 109 110 order = get_count_order(((size - 1) >> PAGE_SHIFT) + 1); 111 112 __free_dma_pages(virt_to_phys(vaddr), order); 113} 114EXPORT_SYMBOL(dma_free_coherent); 115 116/* 117 * Initialise the coherent DMA memory allocator using the given uncached region. 118 */ 119void __init coherent_mem_init(phys_addr_t start, u32 size) 120{ 121 phys_addr_t bitmap_phys; 122 123 if (!size) 124 return; 125 126 printk(KERN_INFO 127 "Coherent memory (DMA) region start=0x%x size=0x%x\n", 128 start, size); 129 130 dma_base = start; 131 dma_size = size; 132 133 /* allocate bitmap */ 134 dma_pages = dma_size >> PAGE_SHIFT; 135 if (dma_size & (PAGE_SIZE - 1)) 136 ++dma_pages; 137 138 bitmap_phys = memblock_alloc(BITS_TO_LONGS(dma_pages) * sizeof(long), 139 sizeof(long)); 140 141 dma_bitmap = phys_to_virt(bitmap_phys); 142 memset(dma_bitmap, 0, dma_pages * PAGE_SIZE); 143} 144