1 /* 2 * Copyright 2010 Red Hat Inc. 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice shall be included in 12 * all copies or substantial portions of the Software. 13 * 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR 18 * 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 OR 20 * OTHER DEALINGS IN THE SOFTWARE. 21 * 22 * Authors: Ben Skeggs 23 */ 24 #include "pll.h" 25 26 #include <subdev/bios.h> 27 #include <subdev/bios/pll.h> 28 29 int 30 gt215_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 nv_error(subdev, "unable to find matching pll values\n"); 83 return -EINVAL; 84 } 85 86 return info->refclk * *pN / *pM / *P; 87 } 88