src/southbridge/intel/lynxpoint/hda_verb.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <console/console.h>
   4 #include <device/azalia_device.h>
   5 #include <device/mmio.h>
   6
   7 #include "hda_verb.h"
   8
   9 int hda_codec_detect(u8 *base)
  10 {
  11         u8 reg8;
  12
  13         /* Set Bit 0 to 1 to exit reset state (BAR + 0x8)[0] */
  14         if (azalia_exit_reset(base) < 0)
  15                 goto no_codec;
  16
  17         /* Write back the value once reset bit is set. */
  18         write16(base + HDA_GCAP_REG, read16(base + HDA_GCAP_REG));
  19
  20         /*
  21          * Clear the "State Change Status Register" STATESTS bits
  22          * for each of the "SDIN Stat Change Status Flag"
  23          */
  24         write8(base + HDA_STATESTS_REG, 0xf);
  25
  26         /* Turn off the link and poll RESET# bit until it reads back as 0 */
  27         if (azalia_enter_reset(base) < 0)
  28                 goto no_codec;
  29
  30         /* Turn on the link and poll RESET# bit until it reads back as 1 */
  31         if (azalia_exit_reset(base) < 0)
  32                 goto no_codec;
  33
  34         /* Read in Codec location (BAR + 0xe)[2..0] */
  35         reg8 = read8(base + HDA_STATESTS_REG);
  36         reg8 &= 0x0f;
  37         if (!reg8)
  38                 goto no_codec;
  39
  40         return reg8;
  41
  42 no_codec:
  43         /* Codec not found, put HDA back in reset */
  44         azalia_enter_reset(base);
  45         printk(BIOS_DEBUG, "HDA: No codec!\n");
  46         return 0;
  47 }