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