1/* 2 * Copyright 1993-2003 NVIDIA, Corporation 3 * Copyright 2007-2009 Stuart Bennett 4 * 5 * Permission is hereby granted, free of charge, to any person obtaining a 6 * copy of this software and associated documentation files (the "Software"), 7 * to deal in the Software without restriction, including without limitation 8 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 9 * and/or sell copies of the Software, and to permit persons to whom the 10 * Software is furnished to do so, subject to the following conditions: 11 * 12 * The above copyright notice and this permission notice shall be included in 13 * all copies or substantial portions of the Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 19 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF 20 * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 * SOFTWARE. 22 */ 23#include "pll.h" 24 25#include <subdev/bios.h> 26#include <subdev/bios/pll.h> 27 28static int 29getMNP_single(struct nvkm_subdev *subdev, struct nvbios_pll *info, int clk, 30 int *pN, int *pM, int *pP) 31{ 32 /* Find M, N and P for a single stage PLL 33 * 34 * Note that some bioses (NV3x) have lookup tables of precomputed MNP 35 * values, but we're too lazy to use those atm 36 * 37 * "clk" parameter in kHz 38 * returns calculated clock 39 */ 40 struct nvkm_bios *bios = subdev->device->bios; 41 int minvco = info->vco1.min_freq, maxvco = info->vco1.max_freq; 42 int minM = info->vco1.min_m, maxM = info->vco1.max_m; 43 int minN = info->vco1.min_n, maxN = info->vco1.max_n; 44 int minU = info->vco1.min_inputfreq; 45 int maxU = info->vco1.max_inputfreq; 46 int minP = info->min_p; 47 int maxP = info->max_p_usable; 48 int crystal = info->refclk; 49 int M, N, thisP, P; 50 int clkP, calcclk; 51 int delta, bestdelta = INT_MAX; 52 int bestclk = 0; 53 54 /* this division verified for nv20, nv18, nv28 (Haiku), and nv34 */ 55 /* possibly correlated with introduction of 27MHz crystal */ 56 if (bios->version.major < 0x60) { 57 int cv = bios->version.chip; 58 if (cv < 0x17 || cv == 0x1a || cv == 0x20) { 59 if (clk > 250000) 60 maxM = 6; 61 if (clk > 340000) 62 maxM = 2; 63 } else if (cv < 0x40) { 64 if (clk > 150000) 65 maxM = 6; 66 if (clk > 200000) 67 maxM = 4; 68 if (clk > 340000) 69 maxM = 2; 70 } 71 } 72 73 P = 1 << maxP; 74 if ((clk * P) < minvco) { 75 minvco = clk * maxP; 76 maxvco = minvco * 2; 77 } 78 79 if (clk + clk/200 > maxvco) /* +0.5% */ 80 maxvco = clk + clk/200; 81 82 /* NV34 goes maxlog2P->0, NV20 goes 0->maxlog2P */ 83 for (thisP = minP; thisP <= maxP; thisP++) { 84 P = 1 << thisP; 85 clkP = clk * P; 86 87 if (clkP < minvco) 88 continue; 89 if (clkP > maxvco) 90 return bestclk; 91 92 for (M = minM; M <= maxM; M++) { 93 if (crystal/M < minU) 94 return bestclk; 95 if (crystal/M > maxU) 96 continue; 97 98 /* add crystal/2 to round better */ 99 N = (clkP * M + crystal/2) / crystal; 100 101 if (N < minN) 102 continue; 103 if (N > maxN) 104 break; 105 106 /* more rounding additions */ 107 calcclk = ((N * crystal + P/2) / P + M/2) / M; 108 delta = abs(calcclk - clk); 109 /* we do an exhaustive search rather than terminating 110 * on an optimality condition... 111 */ 112 if (delta < bestdelta) { 113 bestdelta = delta; 114 bestclk = calcclk; 115 *pN = N; 116 *pM = M; 117 *pP = thisP; 118 if (delta == 0) /* except this one */ 119 return bestclk; 120 } 121 } 122 } 123 124 return bestclk; 125} 126 127static int 128getMNP_double(struct nvkm_subdev *subdev, struct nvbios_pll *info, int clk, 129 int *pN1, int *pM1, int *pN2, int *pM2, int *pP) 130{ 131 /* Find M, N and P for a two stage PLL 132 * 133 * Note that some bioses (NV30+) have lookup tables of precomputed MNP 134 * values, but we're too lazy to use those atm 135 * 136 * "clk" parameter in kHz 137 * returns calculated clock 138 */ 139 int chip_version = subdev->device->bios->version.chip; 140 int minvco1 = info->vco1.min_freq, maxvco1 = info->vco1.max_freq; 141 int minvco2 = info->vco2.min_freq, maxvco2 = info->vco2.max_freq; 142 int minU1 = info->vco1.min_inputfreq, minU2 = info->vco2.min_inputfreq; 143 int maxU1 = info->vco1.max_inputfreq, maxU2 = info->vco2.max_inputfreq; 144 int minM1 = info->vco1.min_m, maxM1 = info->vco1.max_m; 145 int minN1 = info->vco1.min_n, maxN1 = info->vco1.max_n; 146 int minM2 = info->vco2.min_m, maxM2 = info->vco2.max_m; 147 int minN2 = info->vco2.min_n, maxN2 = info->vco2.max_n; 148 int maxlog2P = info->max_p_usable; 149 int crystal = info->refclk; 150 bool fixedgain2 = (minM2 == maxM2 && minN2 == maxN2); 151 int M1, N1, M2, N2, log2P; 152 int clkP, calcclk1, calcclk2, calcclkout; 153 int delta, bestdelta = INT_MAX; 154 int bestclk = 0; 155 156 int vco2 = (maxvco2 - maxvco2/200) / 2; 157 for (log2P = 0; clk && log2P < maxlog2P && clk <= (vco2 >> log2P); log2P++) 158 ; 159 clkP = clk << log2P; 160 161 if (maxvco2 < clk + clk/200) /* +0.5% */ 162 maxvco2 = clk + clk/200; 163 164 for (M1 = minM1; M1 <= maxM1; M1++) { 165 if (crystal/M1 < minU1) 166 return bestclk; 167 if (crystal/M1 > maxU1) 168 continue; 169 170 for (N1 = minN1; N1 <= maxN1; N1++) { 171 calcclk1 = crystal * N1 / M1; 172 if (calcclk1 < minvco1) 173 continue; 174 if (calcclk1 > maxvco1) 175 break; 176 177 for (M2 = minM2; M2 <= maxM2; M2++) { 178 if (calcclk1/M2 < minU2) 179 break; 180 if (calcclk1/M2 > maxU2) 181 continue; 182 183 /* add calcclk1/2 to round better */ 184 N2 = (clkP * M2 + calcclk1/2) / calcclk1; 185 if (N2 < minN2) 186 continue; 187 if (N2 > maxN2) 188 break; 189 190 if (!fixedgain2) { 191 if (chip_version < 0x60) 192 if (N2/M2 < 4 || N2/M2 > 10) 193 continue; 194 195 calcclk2 = calcclk1 * N2 / M2; 196 if (calcclk2 < minvco2) 197 break; 198 if (calcclk2 > maxvco2) 199 continue; 200 } else 201 calcclk2 = calcclk1; 202 203 calcclkout = calcclk2 >> log2P; 204 delta = abs(calcclkout - clk); 205 /* we do an exhaustive search rather than terminating 206 * on an optimality condition... 207 */ 208 if (delta < bestdelta) { 209 bestdelta = delta; 210 bestclk = calcclkout; 211 *pN1 = N1; 212 *pM1 = M1; 213 *pN2 = N2; 214 *pM2 = M2; 215 *pP = log2P; 216 if (delta == 0) /* except this one */ 217 return bestclk; 218 } 219 } 220 } 221 } 222 223 return bestclk; 224} 225 226int 227nv04_pll_calc(struct nvkm_subdev *subdev, struct nvbios_pll *info, u32 freq, 228 int *N1, int *M1, int *N2, int *M2, int *P) 229{ 230 int ret; 231 232 if (!info->vco2.max_freq || !N2) { 233 ret = getMNP_single(subdev, info, freq, N1, M1, P); 234 if (N2) { 235 *N2 = 1; 236 *M2 = 1; 237 } 238 } else { 239 ret = getMNP_double(subdev, info, freq, N1, M1, N2, M2, P); 240 } 241 242 if (!ret) 243 nvkm_error(subdev, "unable to compute acceptable pll values\n"); 244 return ret; 245} 246