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 "drmP.h"
  26 #include "drm_fixed.h"
  27 #include "nouveau_drv.h"
  28 #include "nouveau_hw.h"
  29
  30 int
  31 nv50_calc_pll(struct drm_device *dev, struct pll_lims *pll, int clk,
  32               int *N1, int *M1, int *N2, int *M2, int *P)
  33 {
  34         struct nouveau_pll_vals pll_vals;
  35         int ret;
  36
  37         ret = nouveau_calc_pll_mnp(dev, pll, clk, &pll_vals);
  38         if (ret <= 0)
  39                 return ret;
  40
  41         *N1 = pll_vals.N1;
  42         *M1 = pll_vals.M1;
  43         *N2 = pll_vals.N2;
  44         *M2 = pll_vals.M2;
  45         *P = pll_vals.log2P;
  46         return ret;
  47 }
  48
  49 int
  50 nv50_calc_pll2(struct drm_device *dev, struct pll_lims *pll, int clk,
  51                int *N, int *fN, int *M, int *P)
  52 {
  53         fixed20_12 fb_div, a, b;
  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         /* *M = ceil(refclk / pll->vco.max_inputfreq); */
  62         a.full = dfixed_const(pll->refclk);
  63         b.full = dfixed_const(pll->vco1.max_inputfreq);
  64         a.full = dfixed_div(a, b);
  65         a.full = dfixed_ceil(a);
  66         *M = dfixed_trunc(a);
  67
  68         /* fb_div = (vco * *M) / refclk; */
  69         fb_div.full = dfixed_const(clk * *P);
  70         fb_div.full = dfixed_mul(fb_div, a);
  71         a.full = dfixed_const(pll->refclk);
  72         fb_div.full = dfixed_div(fb_div, a);
  73
  74         /* *N = floor(fb_div); */
  75         a.full = dfixed_floor(fb_div);
  76         *N = dfixed_trunc(fb_div);
  77
  78         /* *fN = (fmod(fb_div, 1.0) * 8192) - 4096; */
  79         b.full = dfixed_const(8192);
  80         a.full = dfixed_mul(a, b);
  81         fb_div.full = dfixed_mul(fb_div, b);
  82         fb_div.full = fb_div.full - a.full;
  83         *fN = dfixed_trunc(fb_div) - 4096;
  84         *fN &= 0xffff;
  85
  86         return clk;
  87 }