88 lines
2.4 KiB
C
88 lines
2.4 KiB
C
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/*
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* Copyright 2010 Red Hat Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
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* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*
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* Authors: Ben Skeggs
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*/
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#include "pll.h"
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#include <subdev/bios.h>
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#include <subdev/bios/pll.h>
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int
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gt215_pll_calc(struct nvkm_subdev *subdev, struct nvbios_pll *info,
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u32 freq, int *pN, int *pfN, int *pM, int *P)
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{
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u32 best_err = ~0, err;
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int M, lM, hM, N, fN;
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*P = info->vco1.max_freq / freq;
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if (*P > info->max_p)
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*P = info->max_p;
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if (*P < info->min_p)
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*P = info->min_p;
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lM = (info->refclk + info->vco1.max_inputfreq) / info->vco1.max_inputfreq;
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lM = max(lM, (int)info->vco1.min_m);
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hM = (info->refclk + info->vco1.min_inputfreq) / info->vco1.min_inputfreq;
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hM = min(hM, (int)info->vco1.max_m);
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lM = min(lM, hM);
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for (M = lM; M <= hM; M++) {
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u32 tmp = freq * *P * M;
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N = tmp / info->refclk;
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fN = tmp % info->refclk;
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if (!pfN) {
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if (fN >= info->refclk / 2)
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N++;
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} else {
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if (fN < info->refclk / 2)
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N--;
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fN = tmp - (N * info->refclk);
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}
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if (N < info->vco1.min_n)
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continue;
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if (N > info->vco1.max_n)
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break;
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err = abs(freq - (info->refclk * N / M / *P));
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if (err < best_err) {
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best_err = err;
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*pN = N;
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*pM = M;
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}
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if (pfN) {
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*pfN = ((fN << 13) + info->refclk / 2) / info->refclk;
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*pfN = (*pfN - 4096) & 0xffff;
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return freq;
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}
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}
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if (unlikely(best_err == ~0)) {
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nvkm_error(subdev, "unable to find matching pll values\n");
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return -EINVAL;
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}
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return info->refclk * *pN / *pM / *P;
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}
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