/*
 * 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 <ajoshi@unixbox.com>
 * Copyright (C) 2000, 2001, 06  Ralf Baechle <ralf@linux-mips.org>
 * 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/cpu-type.h>
#include <asm/io.h>

#include <dma-coherence.h>

int coherentio = 0;     /* User defined DMA coherency from command line. */
EXPORT_SYMBOL_GPL(coherentio);
int hw_coherentio = 0;  /* Actual hardware supported DMA coherency setting. */

static int __init setcoherentio(char *str)
{
        coherentio = 1;
        pr_info("Hardware DMA cache coherency (command line)\n");
        return 0;
}
early_param("coherentio", setcoherentio);

static int __init setnocoherentio(char *str)
{
        coherentio = 0;
        pr_info("Software DMA cache coherency (command line)\n");
        return 0;
}
early_param("nocoherentio", setnocoherentio);

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);
}

/*
 * The affected CPUs below in 'cpu_needs_post_dma_flush()' can
 * speculatively fill random cachelines with stale data at any time,
 * requiring an extra flush post-DMA.
 *
 * Warning on the terminology - Linux calls an uncached area coherent;
 * MIPS terminology calls memory areas with hardware maintained coherency
 * coherent.
 */
static inline int cpu_needs_post_dma_flush(struct device *dev)
{
        return !plat_device_is_coherent(dev) &&
               (boot_cpu_type() == CPU_R10000 ||
                boot_cpu_type() == CPU_R12000 ||
                boot_cpu_type() == CPU_BMIPS5000);
}

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);
                        if (!hw_coherentio)
                                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) && !hw_coherentio)
                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_needs_post_dma_flush(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);
#ifdef CONFIG_NEED_SG_DMA_LENGTH
                sg->dma_length = sg->length;
#endif
                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_needs_post_dma_flush(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;

        if (cpu_needs_post_dma_flush(dev))
                for (i = 0; i < nelems; i++, sg++)
                        __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;

        if (!plat_device_is_coherent(dev))
                for (i = 0; i < nelems; i++, sg++)
                        __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);