cpu/74xx_7xx/speed.c

   1 /*
   2  * (C) Copyright 2000-2002
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  */
  23
  24 #include <common.h>
  25 #include <74xx_7xx.h>
  26 #include <asm/processor.h>
  27
  28 #ifdef CONFIG_AMIGAONEG3SE
  29 #include "../board/MAI/AmigaOneG3SE/via686.h"
  30 #endif
  31
  32 static const int hid1_multipliers_x_10[] = {
  33         25,     /* 0000 - 2.5x */
  34         75,     /* 0001 - 7.5x */
  35         70,     /* 0010 - 7x */
  36         10,     /* 0011 - bypass */
  37         20,     /* 0100 - 2x */
  38         65,     /* 0101 - 6.5x */
  39         100,    /* 0110 - 10x */
  40         45,     /* 0111 - 4.5x */
  41         30,     /* 1000 - 3x */
  42         55,     /* 1001 - 5.5x */
  43         40,     /* 1010 - 4x */
  44         50,     /* 1011 - 5x */
  45         80,     /* 1100 - 8x */
  46         60,     /* 1101 - 6x */
  47         35,     /* 1110 - 3.5x */
  48         0       /* 1111 - off */
  49 };
  50
  51 static const int hid1_fx_multipliers_x_10[] = {
  52         00,     /* 0000 - off */
  53         00,     /* 0001 - off */
  54         10,     /* 0010 - bypass */
  55         10,     /* 0011 - bypass */
  56         20,     /* 0100 - 2x */
  57         25,     /* 0101 - 2.5x */
  58         30,     /* 0110 - 3x */
  59         35,     /* 0111 - 3.5x */
  60         40,     /* 1000 - 4x */
  61         45,     /* 1001 - 4.5x */
  62         50,     /* 1010 - 5x */
  63         55,     /* 1011 - 5.5x */
  64         60,     /* 1100 - 6x */
  65         65,     /* 1101 - 6.5x */
  66         70,     /* 1110 - 7x */
  67         75,     /* 1111 - 7.5 */
  68         80,     /* 10000 - 8x */
  69         85,     /* 10001 - 8.5x */
  70         90,     /* 10010 - 9x */
  71         95,     /* 10011 - 9.5x */
  72         100,    /* 10100 - 10x */
  73         110,    /* 10101 - 11x */
  74         120,    /* 10110 - 12x */
  75 };
  76
  77
  78 /* ------------------------------------------------------------------------- */
  79
  80 /*
  81  * Measure CPU clock speed (core clock GCLK1, GCLK2)
  82  *
  83  * (Approx. GCLK frequency in Hz)
  84  */
  85
  86 int get_clocks (void)
  87 {
  88         DECLARE_GLOBAL_DATA_PTR;
  89         ulong clock = 0;
  90
  91         /* calculate the clock frequency based upon the CPU type */
  92         switch (get_cpu_type()) {
  93         case CPU_7455:
  94         case CPU_7457:
  95                 /*
  96                  * It is assumed that the PLL_EXT line is zero.
  97                  * Make sure division is done before multiplication to prevent 32-bit
  98                  * arithmetic overflows which will cause a negative number
  99                  */
 100                 clock = (CFG_BUS_CLK / 10) * hid1_multipliers_x_10[(get_hid1 () >> 13) & 0xF];
 101                 break;
 102
 103         case CPU_750GX:
 104         case CPU_750FX:
 105                 clock = CFG_BUS_CLK * hid1_fx_multipliers_x_10[get_hid1 () >> 27] / 10;
 106                 break;
 107
 108         case CPU_7450:
 109         case CPU_740:
 110         case CPU_740P:
 111         case CPU_745:
 112         case CPU_750CX:
 113         case CPU_750:
 114         case CPU_750P:
 115         case CPU_755:
 116         case CPU_7400:
 117         case CPU_7410:
 118                 /*
 119                  * Make sure division is done before multiplication to prevent 32-bit
 120                  * arithmetic overflows which will cause a negative number
 121                  */
 122                 clock = (CFG_BUS_CLK / 10) * hid1_multipliers_x_10[get_hid1 () >> 28];
 123                 break;
 124
 125         case CPU_UNKNOWN:
 126                printf ("get_gclk_freq(): unknown CPU type\n");
 127                clock = 0;
 128                return (1);
 129         }
 130
 131         gd->cpu_clk = clock;
 132         gd->bus_clk = CFG_BUS_CLK;
 133
 134         return (0);
 135 }
 136
 137 /* ------------------------------------------------------------------------- */