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 #include <types.h>
   7
   8 #include "hda_verb.h"
   9
  10 int hda_codec_detect(u8 *base)
  11 {
  12         u8 reg8;
  13
  14         /* Set Bit 0 to 1 to exit reset state (BAR + 0x8)[0] */
  15         if (azalia_exit_reset(base) != CB_SUCCESS)
  16                 goto no_codec;
  17
  18         /* Write back the value once reset bit is set. */
  19         write16(base + HDA_GCAP_REG, read16(base + HDA_GCAP_REG));
  20
  21         /*
  22          * Clear the "State Change Status Register" STATESTS bits
  23          * for each of the "SDIN Stat Change Status Flag"
  24          */
  25         write8(base + HDA_STATESTS_REG, 0xf);
  26
  27         /* Turn off the link and poll RESET# bit until it reads back as 0 */
  28         if (azalia_enter_reset(base) != CB_SUCCESS)
  29                 goto no_codec;
  30
  31         /* Turn on the link and poll RESET# bit until it reads back as 1 */
  32         if (azalia_exit_reset(base) != CB_SUCCESS)
  33                 goto no_codec;
  34
  35         /* Read in Codec location (BAR + 0xe)[2..0] */
  36         reg8 = read8(base + HDA_STATESTS_REG);
  37         reg8 &= 0x0f;
  38         if (!reg8)
  39                 goto no_codec;
  40
  41         return reg8;
  42
  43 no_codec:
  44         /* Codec not found, put HDA back in reset */
  45         azalia_enter_reset(base);
  46         printk(BIOS_DEBUG, "HDA: No codec!\n");
  47         return 0;
  48 }