diff options
Diffstat (limited to 'arch/c6x/mm/dma-coherent.c')
-rw-r--r-- | arch/c6x/mm/dma-coherent.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/arch/c6x/mm/dma-coherent.c b/arch/c6x/mm/dma-coherent.c new file mode 100644 index 000000000000..4187e5180373 --- /dev/null +++ b/arch/c6x/mm/dma-coherent.c | |||
@@ -0,0 +1,143 @@ | |||
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 | */ | ||
76 | void *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 | } | ||
97 | EXPORT_SYMBOL(dma_alloc_coherent); | ||
98 | |||
99 | /* | ||
100 | * Free DMA coherent memory as defined by the above mapping. | ||
101 | */ | ||
102 | void 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 | } | ||
114 | EXPORT_SYMBOL(dma_free_coherent); | ||
115 | |||
116 | /* | ||
117 | * Initialise the coherent DMA memory allocator using the given uncached region. | ||
118 | */ | ||
119 | void __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 | } | ||