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 24 #include <subdev/bios.h> 25 #include <subdev/bios/pll.h> 26 27 #include "pll.h" 28 29 static int 30 getMNP_single(struct nouveau_subdev *subdev, struct nvbios_pll *info, int clk, 31 int *pN, int *pM, int *pP) 32 { 33 /* Find M, N and P for a single stage PLL 34 * 35 * Note that some bioses (NV3x) have lookup tables of precomputed MNP 36 * values, but we're too lazy to use those atm 37 * 38 * "clk" parameter in kHz 39 * returns calculated clock 40 */ 41 struct nouveau_bios *bios = nouveau_bios(subdev); 42 int minvco = info->vco1.min_freq, maxvco = info->vco1.max_freq; 43 int minM = info->vco1.min_m, maxM = info->vco1.max_m; 44 int minN = info->vco1.min_n, maxN = info->vco1.max_n; 45 int minU = info->vco1.min_inputfreq; 46 int maxU = info->vco1.max_inputfreq; 47 int minP = info->min_p; 48 int maxP = info->max_p_usable; 49 int crystal = info->refclk; 50 int M, N, thisP, P; 51 int clkP, calcclk; 52 int delta, bestdelta = INT_MAX; 53 int bestclk = 0; 54 55 /* this division verified for nv20, nv18, nv28 (Haiku), and nv34 */ 56 /* possibly correlated with introduction of 27MHz crystal */ 57 if (bios->version.major < 0x60) { 58 int cv = bios->version.chip; 59 if (cv < 0x17 || cv == 0x1a || cv == 0x20) { 60 if (clk > 250000) 61 maxM = 6; 62 if (clk > 340000) 63 maxM = 2; 64 } else if (cv < 0x40) { 65 if (clk > 150000) 66 maxM = 6; 67 if (clk > 200000) 68 maxM = 4; 69 if (clk > 340000) 70 maxM = 2; 71 } 72 } 73 74 P = 1 << maxP; 75 if ((clk * P) < minvco) { 76 minvco = clk * maxP; 77 maxvco = minvco * 2; 78 } 79 80 if (clk + clk/200 > maxvco) /* +0.5% */ 81 maxvco = clk + clk/200; 82 83 /* NV34 goes maxlog2P->0, NV20 goes 0->maxlog2P */ 84 for (thisP = minP; thisP <= maxP; thisP++) { 85 P = 1 << thisP; 86 clkP = clk * P; 87 88 if (clkP < minvco) 89 continue; 90 if (clkP > maxvco) 91 return bestclk; 92 93 for (M = minM; M <= maxM; M++) { 94 if (crystal/M < minU) 95 return bestclk; 96 if (crystal/M > maxU) 97 continue; 98 99 /* add crystal/2 to round better */ 100 N = (clkP * M + crystal/2) / crystal; 101 102 if (N < minN) 103 continue; 104 if (N > maxN) 105 break; 106 107 /* more rounding additions */ 108 calcclk = ((N * crystal + P/2) / P + M/2) / M; 109 delta = abs(calcclk - clk); 110 /* we do an exhaustive search rather than terminating 111 * on an optimality condition... 112 */ 113 if (delta < bestdelta) { 114 bestdelta = delta; 115 bestclk = calcclk; 116 *pN = N; 117 *pM = M; 118 *pP = thisP; 119 if (delta == 0) /* except this one */ 120 return bestclk; 121 } 122 } 123 } 124 125 return bestclk; 126 } 127 128 static int 129 getMNP_double(struct nouveau_subdev *subdev, struct nvbios_pll *info, int clk, 130 int *pN1, int *pM1, int *pN2, int *pM2, int *pP) 131 { 132 /* Find M, N and P for a two stage PLL 133 * 134 * Note that some bioses (NV30+) have lookup tables of precomputed MNP 135 * values, but we're too lazy to use those atm 136 * 137 * "clk" parameter in kHz 138 * returns calculated clock 139 */ 140 int chip_version = nouveau_bios(subdev)->version.chip; 141 int minvco1 = info->vco1.min_freq, maxvco1 = info->vco1.max_freq; 142 int minvco2 = info->vco2.min_freq, maxvco2 = info->vco2.max_freq; 143 int minU1 = info->vco1.min_inputfreq, minU2 = info->vco2.min_inputfreq; 144 int maxU1 = info->vco1.max_inputfreq, maxU2 = info->vco2.max_inputfreq; 145 int minM1 = info->vco1.min_m, maxM1 = info->vco1.max_m; 146 int minN1 = info->vco1.min_n, maxN1 = info->vco1.max_n; 147 int minM2 = info->vco2.min_m, maxM2 = info->vco2.max_m; 148 int minN2 = info->vco2.min_n, maxN2 = info->vco2.max_n; 149 int maxlog2P = info->max_p_usable; 150 int crystal = info->refclk; 151 bool fixedgain2 = (minM2 == maxM2 && minN2 == maxN2); 152 int M1, N1, M2, N2, log2P; 153 int clkP, calcclk1, calcclk2, calcclkout; 154 int delta, bestdelta = INT_MAX; 155 int bestclk = 0; 156 157 int vco2 = (maxvco2 - maxvco2/200) / 2; 158 for (log2P = 0; clk && log2P < maxlog2P && clk <= (vco2 >> log2P); log2P++) 159 ; 160 clkP = clk << log2P; 161 162 if (maxvco2 < clk + clk/200) /* +0.5% */ 163 maxvco2 = clk + clk/200; 164 165 for (M1 = minM1; M1 <= maxM1; M1++) { 166 if (crystal/M1 < minU1) 167 return bestclk; 168 if (crystal/M1 > maxU1) 169 continue; 170 171 for (N1 = minN1; N1 <= maxN1; N1++) { 172 calcclk1 = crystal * N1 / M1; 173 if (calcclk1 < minvco1) 174 continue; 175 if (calcclk1 > maxvco1) 176 break; 177 178 for (M2 = minM2; M2 <= maxM2; M2++) { 179 if (calcclk1/M2 < minU2) 180 break; 181 if (calcclk1/M2 > maxU2) 182 continue; 183 184 /* add calcclk1/2 to round better */ 185 N2 = (clkP * M2 + calcclk1/2) / calcclk1; 186 if (N2 < minN2) 187 continue; 188 if (N2 > maxN2) 189 break; 190 191 if (!fixedgain2) { 192 if (chip_version < 0x60) 193 if (N2/M2 < 4 || N2/M2 > 10) 194 continue; 195 196 calcclk2 = calcclk1 * N2 / M2; 197 if (calcclk2 < minvco2) 198 break; 199 if (calcclk2 > maxvco2) 200 continue; 201 } else 202 calcclk2 = calcclk1; 203 204 calcclkout = calcclk2 >> log2P; 205 delta = abs(calcclkout - clk); 206 /* we do an exhaustive search rather than terminating 207 * on an optimality condition... 208 */ 209 if (delta < bestdelta) { 210 bestdelta = delta; 211 bestclk = calcclkout; 212 *pN1 = N1; 213 *pM1 = M1; 214 *pN2 = N2; 215 *pM2 = M2; 216 *pP = log2P; 217 if (delta == 0) /* except this one */ 218 return bestclk; 219 } 220 } 221 } 222 } 223 224 return bestclk; 225 } 226 227 int 228 nv04_pll_calc(struct nouveau_subdev *subdev, struct nvbios_pll *info, u32 freq, 229 int *N1, int *M1, int *N2, int *M2, int *P) 230 { 231 int ret; 232 233 if (!info->vco2.max_freq || !N2) { 234 ret = getMNP_single(subdev, info, freq, N1, M1, P); 235 if (N2) { 236 *N2 = 1; 237 *M2 = 1; 238 } 239 } else { 240 ret = getMNP_double(subdev, info, freq, N1, M1, N2, M2, P); 241 } 242 243 if (!ret) 244 nv_error(subdev, "unable to compute acceptable pll values\n"); 245 return ret; 246 } 247