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;
}