drivers/gpu/drm/nouveau/nv50_calc.c

   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
  25 #include <drm/drmP.h>
  26 #include "nouveau_drv.h"
  27 #include "nouveau_hw.h"
  28
  29 int
  30 nv50_calc_pll(struct drm_device *dev, struct pll_lims *pll, int clk,
  31               int *N1, int *M1, int *N2, int *M2, int *P)
  32 {
  33         struct nouveau_pll_vals pll_vals;
  34         int ret;
  35
  36         ret = nouveau_calc_pll_mnp(dev, pll, clk, &pll_vals);
  37         if (ret <= 0)
  38                 return ret;
  39
  40         *N1 = pll_vals.N1;
  41         *M1 = pll_vals.M1;
  42         *N2 = pll_vals.N2;
  43         *M2 = pll_vals.M2;
  44         *P = pll_vals.log2P;
  45         return ret;
  46 }
  47
  48 int
  49 nva3_calc_pll(struct drm_device *dev, struct pll_lims *pll, int clk,
  50               int *pN, int *pfN, int *pM, int *P)
  51 {
  52         u32 best_err = ~0, err;
  53         int M, lM, hM, N, fN;
  54
  55         *P = pll->vco1.maxfreq / clk;
  56         if (*P > pll->max_p)
  57                 *P = pll->max_p;
  58         if (*P < pll->min_p)
  59                 *P = pll->min_p;
  60
  61         lM = (pll->refclk + pll->vco1.max_inputfreq) / pll->vco1.max_inputfreq;
  62         lM = max(lM, (int)pll->vco1.min_m);
  63         hM = (pll->refclk + pll->vco1.min_inputfreq) / pll->vco1.min_inputfreq;
  64         hM = min(hM, (int)pll->vco1.max_m);
  65
  66         for (M = lM; M <= hM; M++) {
  67                 u32 tmp = clk * *P * M;
  68                 N  = tmp / pll->refclk;
  69                 fN = tmp % pll->refclk;
  70                 if (!pfN && fN >= pll->refclk / 2)
  71                         N++;
  72
  73                 if (N < pll->vco1.min_n)
  74                         continue;
  75                 if (N > pll->vco1.max_n)
  76                         break;
  77
  78                 err = abs(clk - (pll->refclk * N / M / *P));
  79                 if (err < best_err) {
  80                         best_err = err;
  81                         *pN = N;
  82                         *pM = M;
  83                 }
  84
  85                 if (pfN) {
  86                         *pfN = (((fN << 13) / pll->refclk) - 4096) & 0xffff;
  87                         return clk;
  88                 }
  89         }
  90
  91         if (unlikely(best_err == ~0)) {
  92                 NV_ERROR(dev, "unable to find matching pll values\n");
  93                 return -EINVAL;
  94         }
  95
  96         return pll->refclk * *pN / *pM / *P;
  97 }