Line data    Source code

       1             : /*
       2             :  * Copyright 2008 Advanced Micro Devices, Inc.
       3             :  * Copyright 2008 Red Hat Inc.
       4             :  * Copyright 2009 Christian König.
       5             :  *
       6             :  * Permission is hereby granted, free of charge, to any person obtaining a
       7             :  * copy of this software and associated documentation files (the "Software"),
       8             :  * to deal in the Software without restriction, including without limitation
       9             :  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      10             :  * and/or sell copies of the Software, and to permit persons to whom the
      11             :  * Software is furnished to do so, subject to the following conditions:
      12             :  *
      13             :  * The above copyright notice and this permission notice shall be included in
      14             :  * all copies or substantial portions of the Software.
      15             :  *
      16             :  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
      17             :  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
      18             :  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
      19             :  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
      20             :  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
      21             :  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
      22             :  * OTHER DEALINGS IN THE SOFTWARE.
      23             :  *
      24             :  * Authors: Christian König
      25             :  */
      26             : #include <linux/hdmi.h>
      27             : #include <linux/gcd.h>
      28             : 
      29             : #include <drm/amdgpu_drm.h>
      30             : #include "amdgpu.h"
      31             : 
      32             : static const struct amdgpu_afmt_acr amdgpu_afmt_predefined_acr[] = {
      33             :     /*       32kHz        44.1kHz       48kHz    */
      34             :     /* Clock      N     CTS      N     CTS      N     CTS */
      35             :     {  25175,  4096,  25175, 28224, 125875,  6144,  25175 }, /*  25,20/1.001 MHz */
      36             :     {  25200,  4096,  25200,  6272,  28000,  6144,  25200 }, /*  25.20       MHz */
      37             :     {  27000,  4096,  27000,  6272,  30000,  6144,  27000 }, /*  27.00       MHz */
      38             :     {  27027,  4096,  27027,  6272,  30030,  6144,  27027 }, /*  27.00*1.001 MHz */
      39             :     {  54000,  4096,  54000,  6272,  60000,  6144,  54000 }, /*  54.00       MHz */
      40             :     {  54054,  4096,  54054,  6272,  60060,  6144,  54054 }, /*  54.00*1.001 MHz */
      41             :     {  74176,  4096,  74176,  5733,  75335,  6144,  74176 }, /*  74.25/1.001 MHz */
      42             :     {  74250,  4096,  74250,  6272,  82500,  6144,  74250 }, /*  74.25       MHz */
      43             :     { 148352,  4096, 148352,  5733, 150670,  6144, 148352 }, /* 148.50/1.001 MHz */
      44             :     { 148500,  4096, 148500,  6272, 165000,  6144, 148500 }, /* 148.50       MHz */
      45             : };
      46             : 
      47             : 
      48             : /*
      49             :  * calculate CTS and N values if they are not found in the table
      50             :  */
      51           0 : static void amdgpu_afmt_calc_cts(uint32_t clock, int *CTS, int *N, int freq)
      52             : {
      53             :         int n, cts;
      54             :         unsigned long div, mul;
      55             : 
      56             :         /* Safe, but overly large values */
      57           0 :         n = 128 * freq;
      58           0 :         cts = clock * 1000;
      59             : 
      60             :         /* Smallest valid fraction */
      61           0 :         div = gcd(n, cts);
      62             : 
      63           0 :         n /= div;
      64           0 :         cts /= div;
      65             : 
      66             :         /*
      67             :          * The optimal N is 128*freq/1000. Calculate the closest larger
      68             :          * value that doesn't truncate any bits.
      69             :          */
      70           0 :         mul = ((128*freq/1000) + (n-1))/n;
      71             : 
      72           0 :         n *= mul;
      73           0 :         cts *= mul;
      74             : 
      75             :         /* Check that we are in spec (not always possible) */
      76           0 :         if (n < (128*freq/1500))
      77           0 :                 pr_warn("Calculated ACR N value is too small. You may experience audio problems.\n");
      78           0 :         if (n > (128*freq/300))
      79           0 :                 pr_warn("Calculated ACR N value is too large. You may experience audio problems.\n");
      80             : 
      81           0 :         *N = n;
      82           0 :         *CTS = cts;
      83             : 
      84           0 :         DRM_DEBUG("Calculated ACR timing N=%d CTS=%d for frequency %d\n",
      85             :                   *N, *CTS, freq);
      86           0 : }
      87             : 
      88           0 : struct amdgpu_afmt_acr amdgpu_afmt_acr(uint32_t clock)
      89             : {
      90             :         struct amdgpu_afmt_acr res;
      91             :         u8 i;
      92             : 
      93             :         /* Precalculated values for common clocks */
      94           0 :         for (i = 0; i < ARRAY_SIZE(amdgpu_afmt_predefined_acr); i++) {
      95           0 :                 if (amdgpu_afmt_predefined_acr[i].clock == clock)
      96           0 :                         return amdgpu_afmt_predefined_acr[i];
      97             :         }
      98             : 
      99             :         /* And odd clocks get manually calculated */
     100           0 :         amdgpu_afmt_calc_cts(clock, &res.cts_32khz, &res.n_32khz, 32000);
     101           0 :         amdgpu_afmt_calc_cts(clock, &res.cts_44_1khz, &res.n_44_1khz, 44100);
     102           0 :         amdgpu_afmt_calc_cts(clock, &res.cts_48khz, &res.n_48khz, 48000);
     103             : 
     104           0 :         return res;
     105             : }