dma.c

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/*
 *  Copyright (C) 2011 Texas Instruments Incorporated
 *  Author: Mark Salter <[email protected]>
 *
 *  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.
 */
#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <linux/mm.h>
#include <linux/mm_types.h>
#include <linux/scatterlist.h>

#include <asm/cacheflush.h>

static void c6x_dma_sync(dma_addr_t handle, size_t size,
             enum dma_data_direction dir)
{
    unsigned long paddr = handle;

    BUG_ON(!valid_dma_direction(dir));

    switch (dir) {
    case DMA_FROM_DEVICE:
        L2_cache_block_invalidate(paddr, paddr + size);
        break;
    case DMA_TO_DEVICE:
        L2_cache_block_writeback(paddr, paddr + size);
        break;
    case DMA_BIDIRECTIONAL:
        L2_cache_block_writeback_invalidate(paddr, paddr + size);
        break;
    default:
        break;
    }
}

dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
              enum dma_data_direction dir)
{
    dma_addr_t addr = virt_to_phys(ptr);

    c6x_dma_sync(addr, size, dir);

    debug_dma_map_page(dev, virt_to_page(ptr),
               (unsigned long)ptr & ~PAGE_MASK, size,
               dir, addr, true);
    return addr;
}
EXPORT_SYMBOL(dma_map_single);


void dma_unmap_single(struct device *dev, dma_addr_t handle,
              size_t size, enum dma_data_direction dir)
{
    c6x_dma_sync(handle, size, dir);

    debug_dma_unmap_page(dev, handle, size, dir, true);
}
EXPORT_SYMBOL(dma_unmap_single);


int dma_map_sg(struct device *dev, struct scatterlist *sglist,
           int nents, enum dma_data_direction dir)
{
    struct scatterlist *sg;
    int i;

    for_each_sg(sglist, sg, nents, i)
        sg->dma_address = dma_map_single(dev, sg_virt(sg), sg->length,
                         dir);

    debug_dma_map_sg(dev, sglist, nents, nents, dir);

    return nents;
}
EXPORT_SYMBOL(dma_map_sg);


void dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
          int nents, enum dma_data_direction dir)
{
    struct scatterlist *sg;
    int i;

    for_each_sg(sglist, sg, nents, i)
        dma_unmap_single(dev, sg_dma_address(sg), sg->length, dir);

    debug_dma_unmap_sg(dev, sglist, nents, dir);
}
EXPORT_SYMBOL(dma_unmap_sg);

void dma_sync_single_for_cpu(struct device *dev, dma_addr_t handle,
                 size_t size, enum dma_data_direction dir)
{
    c6x_dma_sync(handle, size, dir);

    debug_dma_sync_single_for_cpu(dev, handle, size, dir);
}
EXPORT_SYMBOL(dma_sync_single_for_cpu);


void dma_sync_single_for_device(struct device *dev, dma_addr_t handle,
                size_t size, enum dma_data_direction dir)
{
    c6x_dma_sync(handle, size, dir);

    debug_dma_sync_single_for_device(dev, handle, size, dir);
}
EXPORT_SYMBOL(dma_sync_single_for_device);


void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sglist,
             int nents, enum dma_data_direction dir)
{
    struct scatterlist *sg;
    int i;

    for_each_sg(sglist, sg, nents, i)
        dma_sync_single_for_cpu(dev, sg_dma_address(sg),
                    sg->length, dir);

    debug_dma_sync_sg_for_cpu(dev, sglist, nents, dir);
}
EXPORT_SYMBOL(dma_sync_sg_for_cpu);


void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sglist,
                int nents, enum dma_data_direction dir)
{
    struct scatterlist *sg;
    int i;

    for_each_sg(sglist, sg, nents, i)
        dma_sync_single_for_device(dev, sg_dma_address(sg),
                       sg->length, dir);

    debug_dma_sync_sg_for_device(dev, sglist, nents, dir);
}
EXPORT_SYMBOL(dma_sync_sg_for_device);


/* Number of entries preallocated for DMA-API debugging */
#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)

static int __init dma_init(void)
{
    dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);

    return 0;
}
fs_initcall(dma_init);