arch/blackfin/mm/maccess.c

   1 /*
   2  * safe read and write memory routines callable while atomic
   3  *
   4  * Copyright 2005-2008 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #include <linux/uaccess.h>
  10 #include <asm/dma.h>
  11
  12 static int validate_memory_access_address(unsigned long addr, int size)
  13 {
  14         if (size < 0 || addr == 0)
  15                 return -EFAULT;
  16         return bfin_mem_access_type(addr, size);
  17 }
  18
  19 long probe_kernel_read(void *dst, void *src, size_t size)
  20 {
  21         unsigned long lsrc = (unsigned long)src;
  22         int mem_type;
  23
  24         mem_type = validate_memory_access_address(lsrc, size);
  25         if (mem_type < 0)
  26                 return mem_type;
  27
  28         if (lsrc >= SYSMMR_BASE) {
  29                 if (size == 2 && lsrc % 2 == 0) {
  30                         u16 mmr = bfin_read16(src);
  31                         memcpy(dst, &mmr, sizeof(mmr));
  32                         return 0;
  33                 } else if (size == 4 && lsrc % 4 == 0) {
  34                         u32 mmr = bfin_read32(src);
  35                         memcpy(dst, &mmr, sizeof(mmr));
  36                         return 0;
  37                 }
  38         } else {
  39                 switch (mem_type) {
  40                 case BFIN_MEM_ACCESS_CORE:
  41                 case BFIN_MEM_ACCESS_CORE_ONLY:
  42                         return __probe_kernel_read(dst, src, size);
  43                         /* XXX: should support IDMA here with SMP */
  44                 case BFIN_MEM_ACCESS_DMA:
  45                         if (dma_memcpy(dst, src, size))
  46                                 return 0;
  47                         break;
  48                 case BFIN_MEM_ACCESS_ITEST:
  49                         if (isram_memcpy(dst, src, size))
  50                                 return 0;
  51                         break;
  52                 }
  53         }
  54
  55         return -EFAULT;
  56 }
  57
  58 long probe_kernel_write(void *dst, void *src, size_t size)
  59 {
  60         unsigned long ldst = (unsigned long)dst;
  61         int mem_type;
  62
  63         mem_type = validate_memory_access_address(ldst, size);
  64         if (mem_type < 0)
  65                 return mem_type;
  66
  67         if (ldst >= SYSMMR_BASE) {
  68                 if (size == 2 && ldst % 2 == 0) {
  69                         u16 mmr;
  70                         memcpy(&mmr, src, sizeof(mmr));
  71                         bfin_write16(dst, mmr);
  72                         return 0;
  73                 } else if (size == 4 && ldst % 4 == 0) {
  74                         u32 mmr;
  75                         memcpy(&mmr, src, sizeof(mmr));
  76                         bfin_write32(dst, mmr);
  77                         return 0;
  78                 }
  79         } else {
  80                 switch (mem_type) {
  81                 case BFIN_MEM_ACCESS_CORE:
  82                 case BFIN_MEM_ACCESS_CORE_ONLY:
  83                         return __probe_kernel_write(dst, src, size);
  84                         /* XXX: should support IDMA here with SMP */
  85                 case BFIN_MEM_ACCESS_DMA:
  86                         if (dma_memcpy(dst, src, size))
  87                                 return 0;
  88                         break;
  89                 case BFIN_MEM_ACCESS_ITEST:
  90                         if (isram_memcpy(dst, src, size))
  91                                 return 0;
  92                         break;
  93                 }
  94         }
  95
  96         return -EFAULT;
  97 }