arch/c6x/mm/dma-coherent.c

   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-noncoherent.h>
  23 #include <linux/memblock.h>
  24
  25 #include <asm/cacheflush.h>
  26 #include <asm/page.h>
  27 #include <asm/setup.h>
  28
  29 /*
  30  * DMA coherent memory management, can be redefined using the memdma=
  31  * kernel command line
  32  */
  33
  34 /* none by default */
  35 static phys_addr_t dma_base;
  36 static u32 dma_size;
  37 static u32 dma_pages;
  38
  39 static unsigned long *dma_bitmap;
  40
  41 /* bitmap lock */
  42 static DEFINE_SPINLOCK(dma_lock);
  43
  44 /*
  45  * Return a DMA coherent and contiguous memory chunk from the DMA memory
  46  */
  47 static inline u32 __alloc_dma_pages(int order)
  48 {
  49         unsigned long flags;
  50         u32 pos;
  51
  52         spin_lock_irqsave(&dma_lock, flags);
  53         pos = bitmap_find_free_region(dma_bitmap, dma_pages, order);
  54         spin_unlock_irqrestore(&dma_lock, flags);
  55
  56         return dma_base + (pos << PAGE_SHIFT);
  57 }
  58
  59 static void __free_dma_pages(u32 addr, int order)
  60 {
  61         unsigned long flags;
  62         u32 pos = (addr - dma_base) >> PAGE_SHIFT;
  63
  64         if (addr < dma_base || (pos + (1 << order)) >= dma_pages) {
  65                 printk(KERN_ERR "%s: freeing outside range.\n", __func__);
  66                 BUG();
  67         }
  68
  69         spin_lock_irqsave(&dma_lock, flags);
  70         bitmap_release_region(dma_bitmap, pos, order);
  71         spin_unlock_irqrestore(&dma_lock, flags);
  72 }
  73
  74 /*
  75  * Allocate DMA coherent memory space and return both the kernel
  76  * virtual and DMA address for that space.
  77  */
  78 void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
  79                 gfp_t gfp, unsigned long attrs)
  80 {
  81         u32 paddr;
  82         int order;
  83
  84         if (!dma_size || !size)
  85                 return NULL;
  86
  87         order = get_count_order(((size - 1) >> PAGE_SHIFT) + 1);
  88
  89         paddr = __alloc_dma_pages(order);
  90
  91         if (handle)
  92                 *handle = paddr;
  93
  94         if (!paddr)
  95                 return NULL;
  96
  97         return phys_to_virt(paddr);
  98 }
  99
 100 /*
 101  * Free DMA coherent memory as defined by the above mapping.
 102  */
 103 void arch_dma_free(struct device *dev, size_t size, void *vaddr,
 104                 dma_addr_t dma_handle, unsigned long attrs)
 105 {
 106         int order;
 107
 108         if (!dma_size || !size)
 109                 return;
 110
 111         order = get_count_order(((size - 1) >> PAGE_SHIFT) + 1);
 112
 113         __free_dma_pages(virt_to_phys(vaddr), order);
 114 }
 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 }
 144
 145 static void c6x_dma_sync(struct device *dev, phys_addr_t paddr, size_t size,
 146                 enum dma_data_direction dir)
 147 {
 148         BUG_ON(!valid_dma_direction(dir));
 149
 150         switch (dir) {
 151         case DMA_FROM_DEVICE:
 152                 L2_cache_block_invalidate(paddr, paddr + size);
 153                 break;
 154         case DMA_TO_DEVICE:
 155                 L2_cache_block_writeback(paddr, paddr + size);
 156                 break;
 157         case DMA_BIDIRECTIONAL:
 158                 L2_cache_block_writeback_invalidate(paddr, paddr + size);
 159                 break;
 160         default:
 161                 break;
 162         }
 163 }
 164
 165 void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
 166                 size_t size, enum dma_data_direction dir)
 167 {
 168         return c6x_dma_sync(dev, paddr, size, dir);
 169 }
 170
 171 void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
 172                 size_t size, enum dma_data_direction dir)
 173 {
 174         return c6x_dma_sync(dev, paddr, size, dir);
 175 }