dma-default.c

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/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2000  Ani Joshi <[email protected]>
 * Copyright (C) 2000, 2001, 06  Ralf Baechle <[email protected]>
 * swiped from i386, and cloned for MIPS by Geert, polished by Ralf.
 */

#include <linux/types.h>
#include <linux/dma-mapping.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/string.h>
#include <linux/gfp.h>
#include <linux/highmem.h>

#include <asm/cache.h>
#include <asm/io.h>

#include <dma-coherence.h>

static inline struct page *dma_addr_to_page(struct device *dev,
    dma_addr_t dma_addr)
{
    return pfn_to_page(
        plat_dma_addr_to_phys(dev, dma_addr) >> PAGE_SHIFT);
}

/*
 * Warning on the terminology - Linux calls an uncached area coherent;
 * MIPS terminology calls memory areas with hardware maintained coherency
 * coherent.
 */

static inline int cpu_is_noncoherent_r10000(struct device *dev)
{
    return !plat_device_is_coherent(dev) &&
           (current_cpu_type() == CPU_R10000 ||
           current_cpu_type() == CPU_R12000);
}

static gfp_t massage_gfp_flags(const struct device *dev, gfp_t gfp)
{
    gfp_t dma_flag;

    /* ignore region specifiers */
    gfp &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM);

#ifdef CONFIG_ISA
    if (dev == NULL)
        dma_flag = __GFP_DMA;
    else
#endif
#if defined(CONFIG_ZONE_DMA32) && defined(CONFIG_ZONE_DMA)
         if (dev->coherent_dma_mask < DMA_BIT_MASK(32))
            dma_flag = __GFP_DMA;
    else if (dev->coherent_dma_mask < DMA_BIT_MASK(64))
            dma_flag = __GFP_DMA32;
    else
#endif
#if defined(CONFIG_ZONE_DMA32) && !defined(CONFIG_ZONE_DMA)
         if (dev->coherent_dma_mask < DMA_BIT_MASK(64))
        dma_flag = __GFP_DMA32;
    else
#endif
#if defined(CONFIG_ZONE_DMA) && !defined(CONFIG_ZONE_DMA32)
         if (dev->coherent_dma_mask < DMA_BIT_MASK(64))
        dma_flag = __GFP_DMA;
    else
#endif
        dma_flag = 0;

    /* Don't invoke OOM killer */
    gfp |= __GFP_NORETRY;

    return gfp | dma_flag;
}

void *dma_alloc_noncoherent(struct device *dev, size_t size,
    dma_addr_t * dma_handle, gfp_t gfp)
{
    void *ret;

    gfp = massage_gfp_flags(dev, gfp);

    ret = (void *) __get_free_pages(gfp, get_order(size));

    if (ret != NULL) {
        memset(ret, 0, size);
        *dma_handle = plat_map_dma_mem(dev, ret, size);
    }

    return ret;
}
EXPORT_SYMBOL(dma_alloc_noncoherent);

static void *mips_dma_alloc_coherent(struct device *dev, size_t size,
    dma_addr_t * dma_handle, gfp_t gfp, struct dma_attrs *attrs)
{
    void *ret;

    if (dma_alloc_from_coherent(dev, size, dma_handle, &ret))
        return ret;

    gfp = massage_gfp_flags(dev, gfp);

    ret = (void *) __get_free_pages(gfp, get_order(size));

    if (ret) {
        memset(ret, 0, size);
        *dma_handle = plat_map_dma_mem(dev, ret, size);

        if (!plat_device_is_coherent(dev)) {
            dma_cache_wback_inv((unsigned long) ret, size);
            ret = UNCAC_ADDR(ret);
        }
    }

    return ret;
}


void dma_free_noncoherent(struct device *dev, size_t size, void *vaddr,
    dma_addr_t dma_handle)
{
    plat_unmap_dma_mem(dev, dma_handle, size, DMA_BIDIRECTIONAL);
    free_pages((unsigned long) vaddr, get_order(size));
}
EXPORT_SYMBOL(dma_free_noncoherent);

static void mips_dma_free_coherent(struct device *dev, size_t size, void *vaddr,
    dma_addr_t dma_handle, struct dma_attrs *attrs)
{
    unsigned long addr = (unsigned long) vaddr;
    int order = get_order(size);

    if (dma_release_from_coherent(dev, order, vaddr))
        return;

    plat_unmap_dma_mem(dev, dma_handle, size, DMA_BIDIRECTIONAL);

    if (!plat_device_is_coherent(dev))
        addr = CAC_ADDR(addr);

    free_pages(addr, get_order(size));
}

static inline void __dma_sync_virtual(void *addr, size_t size,
    enum dma_data_direction direction)
{
    switch (direction) {
    case DMA_TO_DEVICE:
        dma_cache_wback((unsigned long)addr, size);
        break;

    case DMA_FROM_DEVICE:
        dma_cache_inv((unsigned long)addr, size);
        break;

    case DMA_BIDIRECTIONAL:
        dma_cache_wback_inv((unsigned long)addr, size);
        break;

    default:
        BUG();
    }
}

/*
 * A single sg entry may refer to multiple physically contiguous
 * pages. But we still need to process highmem pages individually.
 * If highmem is not configured then the bulk of this loop gets
 * optimized out.
 */
static inline void __dma_sync(struct page *page,
    unsigned long offset, size_t size, enum dma_data_direction direction)
{
    size_t left = size;

    do {
        size_t len = left;

        if (PageHighMem(page)) {
            void *addr;

            if (offset + len > PAGE_SIZE) {
                if (offset >= PAGE_SIZE) {
                    page += offset >> PAGE_SHIFT;
                    offset &= ~PAGE_MASK;
                }
                len = PAGE_SIZE - offset;
            }

            addr = kmap_atomic(page);
            __dma_sync_virtual(addr + offset, len, direction);
            kunmap_atomic(addr);
        } else
            __dma_sync_virtual(page_address(page) + offset,
                       size, direction);
        offset = 0;
        page++;
        left -= len;
    } while (left);
}

static void mips_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
    size_t size, enum dma_data_direction direction, struct dma_attrs *attrs)
{
    if (cpu_is_noncoherent_r10000(dev))
        __dma_sync(dma_addr_to_page(dev, dma_addr),
               dma_addr & ~PAGE_MASK, size, direction);

    plat_unmap_dma_mem(dev, dma_addr, size, direction);
}

static int mips_dma_map_sg(struct device *dev, struct scatterlist *sg,
    int nents, enum dma_data_direction direction, struct dma_attrs *attrs)
{
    int i;

    for (i = 0; i < nents; i++, sg++) {
        if (!plat_device_is_coherent(dev))
            __dma_sync(sg_page(sg), sg->offset, sg->length,
                   direction);
        sg->dma_address = plat_map_dma_mem_page(dev, sg_page(sg)) +
                  sg->offset;
    }

    return nents;
}

static dma_addr_t mips_dma_map_page(struct device *dev, struct page *page,
    unsigned long offset, size_t size, enum dma_data_direction direction,
    struct dma_attrs *attrs)
{
    if (!plat_device_is_coherent(dev))
        __dma_sync(page, offset, size, direction);

    return plat_map_dma_mem_page(dev, page) + offset;
}

static void mips_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
    int nhwentries, enum dma_data_direction direction,
    struct dma_attrs *attrs)
{
    int i;

    for (i = 0; i < nhwentries; i++, sg++) {
        if (!plat_device_is_coherent(dev) &&
            direction != DMA_TO_DEVICE)
            __dma_sync(sg_page(sg), sg->offset, sg->length,
                   direction);
        plat_unmap_dma_mem(dev, sg->dma_address, sg->length, direction);
    }
}

static void mips_dma_sync_single_for_cpu(struct device *dev,
    dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
{
    if (cpu_is_noncoherent_r10000(dev))
        __dma_sync(dma_addr_to_page(dev, dma_handle),
               dma_handle & ~PAGE_MASK, size, direction);
}

static void mips_dma_sync_single_for_device(struct device *dev,
    dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
{
    plat_extra_sync_for_device(dev);
    if (!plat_device_is_coherent(dev))
        __dma_sync(dma_addr_to_page(dev, dma_handle),
               dma_handle & ~PAGE_MASK, size, direction);
}

static void mips_dma_sync_sg_for_cpu(struct device *dev,
    struct scatterlist *sg, int nelems, enum dma_data_direction direction)
{
    int i;

    /* Make sure that gcc doesn't leave the empty loop body.  */
    for (i = 0; i < nelems; i++, sg++) {
        if (cpu_is_noncoherent_r10000(dev))
            __dma_sync(sg_page(sg), sg->offset, sg->length,
                   direction);
    }
}

static void mips_dma_sync_sg_for_device(struct device *dev,
    struct scatterlist *sg, int nelems, enum dma_data_direction direction)
{
    int i;

    /* Make sure that gcc doesn't leave the empty loop body.  */
    for (i = 0; i < nelems; i++, sg++) {
        if (!plat_device_is_coherent(dev))
            __dma_sync(sg_page(sg), sg->offset, sg->length,
                   direction);
    }
}

int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
    return plat_dma_mapping_error(dev, dma_addr);
}

int mips_dma_supported(struct device *dev, u64 mask)
{
    return plat_dma_supported(dev, mask);
}

void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
             enum dma_data_direction direction)
{
    BUG_ON(direction == DMA_NONE);

    plat_extra_sync_for_device(dev);
    if (!plat_device_is_coherent(dev))
        __dma_sync_virtual(vaddr, size, direction);
}

EXPORT_SYMBOL(dma_cache_sync);

static struct dma_map_ops mips_default_dma_map_ops = {
    .alloc = mips_dma_alloc_coherent,
    .free = mips_dma_free_coherent,
    .map_page = mips_dma_map_page,
    .unmap_page = mips_dma_unmap_page,
    .map_sg = mips_dma_map_sg,
    .unmap_sg = mips_dma_unmap_sg,
    .sync_single_for_cpu = mips_dma_sync_single_for_cpu,
    .sync_single_for_device = mips_dma_sync_single_for_device,
    .sync_sg_for_cpu = mips_dma_sync_sg_for_cpu,
    .sync_sg_for_device = mips_dma_sync_sg_for_device,
    .mapping_error = mips_dma_mapping_error,
    .dma_supported = mips_dma_supported
};

struct dma_map_ops *mips_dma_map_ops = &mips_default_dma_map_ops;
EXPORT_SYMBOL(mips_dma_map_ops);

#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)

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

    return 0;
}
fs_initcall(mips_dma_init);