diff options
Diffstat (limited to 'drivers/gpu/drm/amd/amdgpu/amdgpu_afmt.c')
| -rw-r--r-- | drivers/gpu/drm/amd/amdgpu/amdgpu_afmt.c | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_afmt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_afmt.c new file mode 100644 index 000000000000..857ba0897159 --- /dev/null +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_afmt.c @@ -0,0 +1,105 @@ +/* + * 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)) + printk(KERN_WARNING "Calculated ACR N value is too small. You may experience audio problems.\n"); + if (n > (128*freq/300)) + printk(KERN_WARNING "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; +} |