drivers/gpu/drm/nouveau/nvkm/subdev/bios/bit.c

   1 /*
   2  * Copyright 2012 Red Hat Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20  * OTHER DEALINGS IN THE SOFTWARE.
  21  *
  22  * Authors: Ben Skeggs
  23  */
  24 #include <subdev/bios.h>
  25 #include <subdev/bios/bit.h>
  26
  27 int
  28 bit_entry(struct nvkm_bios *bios, u8 id, struct bit_entry *bit)
  29 {
  30         if (likely(bios->bit_offset)) {
  31                 u8  entries = nvbios_rd08(bios, bios->bit_offset + 10);
  32                 u32 entry   = bios->bit_offset + 12;
  33                 while (entries--) {
  34                         if (nvbios_rd08(bios, entry + 0) == id) {
  35                                 bit->id      = nvbios_rd08(bios, entry + 0);
  36                                 bit->version = nvbios_rd08(bios, entry + 1);
  37                                 bit->length  = nvbios_rd16(bios, entry + 2);
  38                                 bit->offset  = nvbios_rd16(bios, entry + 4);
  39                                 return 0;
  40                         }
  41
  42                         entry += nvbios_rd08(bios, bios->bit_offset + 9);
  43                 }
  44
  45                 return -ENOENT;
  46         }
  47
  48         return -EINVAL;
  49 }