dma-coherence.h

Go to the documentation of this file.

/*
 * 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.
 *
 * Version from mach-generic modified to support PowerTV port
 * Portions Copyright (C) 2009  Cisco Systems, Inc.
 * Copyright (C) 2006  Ralf Baechle <[email protected]>
 *
 */

#ifndef __ASM_MACH_POWERTV_DMA_COHERENCE_H
#define __ASM_MACH_POWERTV_DMA_COHERENCE_H

#include <linux/sched.h>
#include <linux/device.h>
#include <asm/mach-powertv/asic.h>

static inline bool is_kseg2(void *addr)
{
    return (unsigned long)addr >= KSEG2;
}

static inline unsigned long virt_to_phys_from_pte(void *addr)
{
    pgd_t *pgd;
    pud_t *pud;
    pmd_t *pmd;
    pte_t *ptep, pte;

    unsigned long virt_addr = (unsigned long)addr;
    unsigned long phys_addr = 0UL;

    /* get the page global directory. */
    pgd = pgd_offset_k(virt_addr);

    if (!pgd_none(*pgd)) {
        /* get the page upper directory */
        pud = pud_offset(pgd, virt_addr);
        if (!pud_none(*pud)) {
            /* get the page middle directory */
            pmd = pmd_offset(pud, virt_addr);
            if (!pmd_none(*pmd)) {
                /* get a pointer to the page table entry */
                ptep = pte_offset(pmd, virt_addr);
                pte = *ptep;
                /* check for a valid page */
                if (pte_present(pte)) {
                    /* get the physical address the page is
                     * referring to */
                    phys_addr = (unsigned long)
                        page_to_phys(pte_page(pte));
                    /* add the offset within the page */
                    phys_addr |= (virt_addr & ~PAGE_MASK);
                }
            }
        }
    }

    return phys_addr;
}

static inline dma_addr_t plat_map_dma_mem(struct device *dev, void *addr,
    size_t size)
{
    if (is_kseg2(addr))
        return phys_to_dma(virt_to_phys_from_pte(addr));
    else
        return phys_to_dma(virt_to_phys(addr));
}

static inline dma_addr_t plat_map_dma_mem_page(struct device *dev,
    struct page *page)
{
    return phys_to_dma(page_to_phys(page));
}

static inline unsigned long plat_dma_addr_to_phys(struct device *dev,
    dma_addr_t dma_addr)
{
    return dma_to_phys(dma_addr);
}

static inline void plat_unmap_dma_mem(struct device *dev, dma_addr_t dma_addr,
    size_t size, enum dma_data_direction direction)
{
}

static inline int plat_dma_supported(struct device *dev, u64 mask)
{
    /*
     * we fall back to GFP_DMA when the mask isn't all 1s,
     * so we can't guarantee allocations that must be
     * within a tighter range than GFP_DMA..
     */
    if (mask < DMA_BIT_MASK(24))
        return 0;

    return 1;
}

static inline void plat_extra_sync_for_device(struct device *dev)
{
}

static inline int plat_dma_mapping_error(struct device *dev,
                     dma_addr_t dma_addr)
{
    return 0;
}

static inline int plat_device_is_coherent(struct device *dev)
{
    return 0;
}

#endif /* __ASM_MACH_POWERTV_DMA_COHERENCE_H */