maccess.c

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/*
 * safe read and write memory routines callable while atomic
 *
 * Copyright 2005-2008 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/uaccess.h>
#include <asm/dma.h>

static int validate_memory_access_address(unsigned long addr, int size)
{
    if (size < 0 || addr == 0)
        return -EFAULT;
    return bfin_mem_access_type(addr, size);
}

long probe_kernel_read(void *dst, const void *src, size_t size)
{
    unsigned long lsrc = (unsigned long)src;
    int mem_type;

    mem_type = validate_memory_access_address(lsrc, size);
    if (mem_type < 0)
        return mem_type;

    if (lsrc >= SYSMMR_BASE) {
        if (size == 2 && lsrc % 2 == 0) {
            u16 mmr = bfin_read16(src);
            memcpy(dst, &mmr, sizeof(mmr));
            return 0;
        } else if (size == 4 && lsrc % 4 == 0) {
            u32 mmr = bfin_read32(src);
            memcpy(dst, &mmr, sizeof(mmr));
            return 0;
        }
    } else {
        switch (mem_type) {
        case BFIN_MEM_ACCESS_CORE:
        case BFIN_MEM_ACCESS_CORE_ONLY:
            return __probe_kernel_read(dst, src, size);
            /* XXX: should support IDMA here with SMP */
        case BFIN_MEM_ACCESS_DMA:
            if (dma_memcpy(dst, src, size))
                return 0;
            break;
        case BFIN_MEM_ACCESS_ITEST:
            if (isram_memcpy(dst, src, size))
                return 0;
            break;
        }
    }

    return -EFAULT;
}

long probe_kernel_write(void *dst, const void *src, size_t size)
{
    unsigned long ldst = (unsigned long)dst;
    int mem_type;

    mem_type = validate_memory_access_address(ldst, size);
    if (mem_type < 0)
        return mem_type;

    if (ldst >= SYSMMR_BASE) {
        if (size == 2 && ldst % 2 == 0) {
            u16 mmr;
            memcpy(&mmr, src, sizeof(mmr));
            bfin_write16(dst, mmr);
            return 0;
        } else if (size == 4 && ldst % 4 == 0) {
            u32 mmr;
            memcpy(&mmr, src, sizeof(mmr));
            bfin_write32(dst, mmr);
            return 0;
        }
    } else {
        switch (mem_type) {
        case BFIN_MEM_ACCESS_CORE:
        case BFIN_MEM_ACCESS_CORE_ONLY:
            return __probe_kernel_write(dst, src, size);
            /* XXX: should support IDMA here with SMP */
        case BFIN_MEM_ACCESS_DMA:
            if (dma_memcpy(dst, src, size))
                return 0;
            break;
        case BFIN_MEM_ACCESS_ITEST:
            if (isram_memcpy(dst, src, size))
                return 0;
            break;
        }
    }

    return -EFAULT;
}