1 /* $NetBSD: amdgpu_afmt.c,v 1.2 2018/08/27 04:58:19 riastradh Exp $ */ 2 3 /* 4 * Copyright 2008 Advanced Micro Devices, Inc. 5 * Copyright 2008 Red Hat Inc. 6 * Copyright 2009 Christian König. 7 * 8 * Permission is hereby granted, free of charge, to any person obtaining a 9 * copy of this software and associated documentation files (the "Software"), 10 * to deal in the Software without restriction, including without limitation 11 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 12 * and/or sell copies of the Software, and to permit persons to whom the 13 * Software is furnished to do so, subject to the following conditions: 14 * 15 * The above copyright notice and this permission notice shall be included in 16 * all copies or substantial portions of the Software. 17 * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 21 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR 22 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 23 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 24 * OTHER DEALINGS IN THE SOFTWARE. 25 * 26 * Authors: Christian König 27 */ 28 #include <sys/cdefs.h> 29 __KERNEL_RCSID(0, "$NetBSD: amdgpu_afmt.c,v 1.2 2018/08/27 04:58:19 riastradh Exp $"); 30 31 #include <linux/hdmi.h> 32 #include <linux/gcd.h> 33 #include <drm/drmP.h> 34 #include <drm/amdgpu_drm.h> 35 #include "amdgpu.h" 36 37 static const struct amdgpu_afmt_acr amdgpu_afmt_predefined_acr[] = { 38 /* 32kHz 44.1kHz 48kHz */ 39 /* Clock N CTS N CTS N CTS */ 40 { 25175, 4096, 25175, 28224, 125875, 6144, 25175 }, /* 25,20/1.001 MHz */ 41 { 25200, 4096, 25200, 6272, 28000, 6144, 25200 }, /* 25.20 MHz */ 42 { 27000, 4096, 27000, 6272, 30000, 6144, 27000 }, /* 27.00 MHz */ 43 { 27027, 4096, 27027, 6272, 30030, 6144, 27027 }, /* 27.00*1.001 MHz */ 44 { 54000, 4096, 54000, 6272, 60000, 6144, 54000 }, /* 54.00 MHz */ 45 { 54054, 4096, 54054, 6272, 60060, 6144, 54054 }, /* 54.00*1.001 MHz */ 46 { 74176, 4096, 74176, 5733, 75335, 6144, 74176 }, /* 74.25/1.001 MHz */ 47 { 74250, 4096, 74250, 6272, 82500, 6144, 74250 }, /* 74.25 MHz */ 48 { 148352, 4096, 148352, 5733, 150670, 6144, 148352 }, /* 148.50/1.001 MHz */ 49 { 148500, 4096, 148500, 6272, 165000, 6144, 148500 }, /* 148.50 MHz */ 50 }; 51 52 53 /* 54 * calculate CTS and N values if they are not found in the table 55 */ 56 static void amdgpu_afmt_calc_cts(uint32_t clock, int *CTS, int *N, int freq) 57 { 58 int n, cts; 59 unsigned long div, mul; 60 61 /* Safe, but overly large values */ 62 n = 128 * freq; 63 cts = clock * 1000; 64 65 /* Smallest valid fraction */ 66 div = gcd(n, cts); 67 68 n /= div; 69 cts /= div; 70 71 /* 72 * The optimal N is 128*freq/1000. Calculate the closest larger 73 * value that doesn't truncate any bits. 74 */ 75 mul = ((128*freq/1000) + (n-1))/n; 76 77 n *= mul; 78 cts *= mul; 79 80 /* Check that we are in spec (not always possible) */ 81 if (n < (128*freq/1500)) 82 printk(KERN_WARNING "Calculated ACR N value is too small. You may experience audio problems.\n"); 83 if (n > (128*freq/300)) 84 printk(KERN_WARNING "Calculated ACR N value is too large. You may experience audio problems.\n"); 85 86 *N = n; 87 *CTS = cts; 88 89 DRM_DEBUG("Calculated ACR timing N=%d CTS=%d for frequency %d\n", 90 *N, *CTS, freq); 91 } 92 93 struct amdgpu_afmt_acr amdgpu_afmt_acr(uint32_t clock) 94 { 95 struct amdgpu_afmt_acr res; 96 u8 i; 97 98 /* Precalculated values for common clocks */ 99 for (i = 0; i < ARRAY_SIZE(amdgpu_afmt_predefined_acr); i++) { 100 if (amdgpu_afmt_predefined_acr[i].clock == clock) 101 return amdgpu_afmt_predefined_acr[i]; 102 } 103 104 /* And odd clocks get manually calculated */ 105 amdgpu_afmt_calc_cts(clock, &res.cts_32khz, &res.n_32khz, 32000); 106 amdgpu_afmt_calc_cts(clock, &res.cts_44_1khz, &res.n_44_1khz, 44100); 107 amdgpu_afmt_calc_cts(clock, &res.cts_48khz, &res.n_48khz, 48000); 108 109 return res; 110 } 111