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/*
* Copyright 2008 Advanced Micro Devices, Inc.
* Copyright 2008 Red Hat Inc.
* Copyright 2009 Christian König.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* Authors: Christian König
*/
#include <linux/hdmi.h>
#include <linux/gcd.h>
#include <drm/drmP.h>
#include <drm/amdgpu_drm.h>
#include "amdgpu.h"
static const struct amdgpu_afmt_acr amdgpu_afmt_predefined_acr[] = {
/* 32kHz 44.1kHz 48kHz */
/* Clock N CTS N CTS N CTS */
{ 25175, 4096, 25175, 28224, 125875, 6144, 25175 }, /* 25,20/1.001 MHz */
{ 25200, 4096, 25200, 6272, 28000, 6144, 25200 }, /* 25.20 MHz */
{ 27000, 4096, 27000, 6272, 30000, 6144, 27000 }, /* 27.00 MHz */
{ 27027, 4096, 27027, 6272, 30030, 6144, 27027 }, /* 27.00*1.001 MHz */
{ 54000, 4096, 54000, 6272, 60000, 6144, 54000 }, /* 54.00 MHz */
{ 54054, 4096, 54054, 6272, 60060, 6144, 54054 }, /* 54.00*1.001 MHz */
{ 74176, 4096, 74176, 5733, 75335, 6144, 74176 }, /* 74.25/1.001 MHz */
{ 74250, 4096, 74250, 6272, 82500, 6144, 74250 }, /* 74.25 MHz */
{ 148352, 4096, 148352, 5733, 150670, 6144, 148352 }, /* 148.50/1.001 MHz */
{ 148500, 4096, 148500, 6272, 165000, 6144, 148500 }, /* 148.50 MHz */
};
/*
* calculate CTS and N values if they are not found in the table
*/
static void amdgpu_afmt_calc_cts(uint32_t clock, int *CTS, int *N, int freq)
{
int n, cts;
unsigned long div, mul;
/* Safe, but overly large values */
n = 128 * freq;
cts = clock * 1000;
/* Smallest valid fraction */
div = gcd(n, cts);
n /= div;
cts /= div;
/*
* The optimal N is 128*freq/1000. Calculate the closest larger
* value that doesn't truncate any bits.
*/
mul = ((128*freq/1000) + (n-1))/n;
n *= mul;
cts *= mul;
/* Check that we are in spec (not always possible) */
if (n < (128*freq/1500))
pr_warn("Calculated ACR N value is too small. You may experience audio problems.\n");
if (n > (128*freq/300))
pr_warn("Calculated ACR N value is too large. You may experience audio problems.\n");
*N = n;
*CTS = cts;
DRM_DEBUG("Calculated ACR timing N=%d CTS=%d for frequency %d\n",
*N, *CTS, freq);
}
struct amdgpu_afmt_acr amdgpu_afmt_acr(uint32_t clock)
{
struct amdgpu_afmt_acr res;
u8 i;
/* Precalculated values for common clocks */
for (i = 0; i < ARRAY_SIZE(amdgpu_afmt_predefined_acr); i++) {
if (amdgpu_afmt_predefined_acr[i].clock == clock)
return amdgpu_afmt_predefined_acr[i];
}
/* And odd clocks get manually calculated */
amdgpu_afmt_calc_cts(clock, &res.cts_32khz, &res.n_32khz, 32000);
amdgpu_afmt_calc_cts(clock, &res.cts_44_1khz, &res.n_44_1khz, 44100);
amdgpu_afmt_calc_cts(clock, &res.cts_48khz, &res.n_48khz, 48000);
return res;
}
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