arch/arm64/kernel/io.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Based on arch/arm/kernel/io.c
   4  *
   5  * Copyright (C) 2012 ARM Ltd.
   6  */
   7
   8 #include <linux/export.h>
   9 #include <linux/types.h>
  10 #include <linux/io.h>
  11
  12 /*
  13  * Copy data from IO memory space to "real" memory space.
  14  */
  15 void __memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
  16 {
  17         while (count && !IS_ALIGNED((unsigned long)from, 8)) {
  18                 *(u8 *)to = __raw_readb(from);
  19                 from++;
  20                 to++;
  21                 count--;
  22         }
  23
  24         while (count >= 8) {
  25                 *(u64 *)to = __raw_readq(from);
  26                 from += 8;
  27                 to += 8;
  28                 count -= 8;
  29         }
  30
  31         while (count) {
  32                 *(u8 *)to = __raw_readb(from);
  33                 from++;
  34                 to++;
  35                 count--;
  36         }
  37 }
  38 EXPORT_SYMBOL(__memcpy_fromio);
  39
  40 /*
  41  * Copy data from "real" memory space to IO memory space.
  42  */
  43 void __memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
  44 {
  45         while (count && !IS_ALIGNED((unsigned long)to, 8)) {
  46                 __raw_writeb(*(u8 *)from, to);
  47                 from++;
  48                 to++;
  49                 count--;
  50         }
  51
  52         while (count >= 8) {
  53                 __raw_writeq(*(u64 *)from, to);
  54                 from += 8;
  55                 to += 8;
  56                 count -= 8;
  57         }
  58
  59         while (count) {
  60                 __raw_writeb(*(u8 *)from, to);
  61                 from++;
  62                 to++;
  63                 count--;
  64         }
  65 }
  66 EXPORT_SYMBOL(__memcpy_toio);
  67
  68 /*
  69  * "memset" on IO memory space.
  70  */
  71 void __memset_io(volatile void __iomem *dst, int c, size_t count)
  72 {
  73         u64 qc = (u8)c;
  74
  75         qc |= qc << 8;
  76         qc |= qc << 16;
  77         qc |= qc << 32;
  78
  79         while (count && !IS_ALIGNED((unsigned long)dst, 8)) {
  80                 __raw_writeb(c, dst);
  81                 dst++;
  82                 count--;
  83         }
  84
  85         while (count >= 8) {
  86                 __raw_writeq(qc, dst);
  87                 dst += 8;
  88                 count -= 8;
  89         }
  90
  91         while (count) {
  92                 __raw_writeb(c, dst);
  93                 dst++;
  94                 count--;
  95         }
  96 }
  97 EXPORT_SYMBOL(__memset_io);