LXR linux/drivers/gpu/drm/nouveau/nv50

   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 "drmP.h"
  26#include "nouveau_drv.h"
  27#include "nouveau_hw.h"
  28
  29int
  30nv50_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
  48int
  49nva3_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}
  98