kernel/drivers/staging/gdm724x/gdm_endian.c

   1 /*
   2  * Copyright (c) 2012 GCT Semiconductor, Inc. All rights reserved.
   3  *
   4  * This software is licensed under the terms of the GNU General Public
   5  * License version 2, as published by the Free Software Foundation, and
   6  * may be copied, distributed, and modified under those terms.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/slab.h>
  15 #include "gdm_endian.h"
  16
  17 void gdm_set_endian(struct gdm_endian *ed, u8 dev_endian)
  18 {
  19         u8 a[2] = {0x12, 0x34};
  20         u8 b[2] = {0, };
  21         u16 c = 0x1234;
  22
  23         if (dev_endian == ENDIANNESS_BIG)
  24                 ed->dev_ed = ENDIANNESS_BIG;
  25         else
  26                 ed->dev_ed = ENDIANNESS_LITTLE;
  27
  28         memcpy(b, &c, 2);
  29
  30         if (a[0] != b[0])
  31                 ed->host_ed = ENDIANNESS_LITTLE;
  32         else
  33                 ed->host_ed = ENDIANNESS_BIG;
  34
  35 }
  36
  37 u16 gdm_cpu_to_dev16(struct gdm_endian *ed, u16 x)
  38 {
  39         if (ed->dev_ed == ed->host_ed)
  40                 return x;
  41
  42         return Endian16_Swap(x);
  43 }
  44
  45 u16 gdm_dev16_to_cpu(struct gdm_endian *ed, u16 x)
  46 {
  47         if (ed->dev_ed == ed->host_ed)
  48                 return x;
  49
  50         return Endian16_Swap(x);
  51 }
  52
  53 u32 gdm_cpu_to_dev32(struct gdm_endian *ed, u32 x)
  54 {
  55         if (ed->dev_ed == ed->host_ed)
  56                 return x;
  57
  58         return Endian32_Swap(x);
  59 }
  60
  61 u32 gdm_dev32_to_cpu(struct gdm_endian *ed, u32 x)
  62 {
  63         if (ed->dev_ed == ed->host_ed)
  64                 return x;
  65
  66         return Endian32_Swap(x);
  67 }