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1/*2 * Copyright 2010 Red Hat Inc.3 *4 * Permission is hereby granted, free of charge, to any person obtaining a5 * copy of this software and associated documentation files (the "Software"),6 * to deal in the Software without restriction, including without limitation7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,8 * and/or sell copies of the Software, and to permit persons to whom the9 * Software is furnished to do so, subject to the following conditions:10 *11 * The above copyright notice and this permission notice shall be included in12 * all copies or substantial portions of the Software.13 *14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR20 * OTHER DEALINGS IN THE SOFTWARE.21 *22 * Authors: Ben Skeggs23 */24#include "pll.h"25 26#include <subdev/bios.h>27#include <subdev/bios/pll.h>28 29int30gt215_pll_calc(struct nvkm_subdev *subdev, struct nvbios_pll *info,31 u32 freq, int *pN, int *pfN, int *pM, int *P)32{33 u32 best_err = ~0, err;34 int M, lM, hM, N, fN;35 36 *P = info->vco1.max_freq / freq;37 if (*P > info->max_p)38 *P = info->max_p;39 if (*P < info->min_p)40 *P = info->min_p;41 42 lM = (info->refclk + info->vco1.max_inputfreq) / info->vco1.max_inputfreq;43 lM = max(lM, (int)info->vco1.min_m);44 hM = (info->refclk + info->vco1.min_inputfreq) / info->vco1.min_inputfreq;45 hM = min(hM, (int)info->vco1.max_m);46 lM = min(lM, hM);47 48 for (M = lM; M <= hM; M++) {49 u32 tmp = freq * *P * M;50 N = tmp / info->refclk;51 fN = tmp % info->refclk;52 53 if (!pfN) {54 if (fN >= info->refclk / 2)55 N++;56 } else {57 if (fN < info->refclk / 2)58 N--;59 fN = tmp - (N * info->refclk);60 }61 62 if (N < info->vco1.min_n)63 continue;64 if (N > info->vco1.max_n)65 break;66 67 err = abs(freq - (info->refclk * N / M / *P));68 if (err < best_err) {69 best_err = err;70 *pN = N;71 *pM = M;72 }73 74 if (pfN) {75 *pfN = ((fN << 13) + info->refclk / 2) / info->refclk;76 *pfN = (*pfN - 4096) & 0xffff;77 return freq;78 }79 }80 81 if (unlikely(best_err == ~0)) {82 nvkm_error(subdev, "unable to find matching pll values\n");83 return -EINVAL;84 }85 86 return info->refclk * *pN / *pM / *P;87}88