cpu/mips/incaip_clock.c

   1 /*
   2  * (C) Copyright 2003
   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 <asm/inca-ip.h>
  26
  27
  28 /*******************************************************************************
  29 *
  30 * get_cpuclk - returns the frequency of the CPU.
  31 *
  32 * Gets the value directly from the INCA-IP hardware.
  33 *
  34 * RETURNS:
  35 *          150.000.000 for 150 MHz
  36 *          130.000.000. for 130 Mhz
  37 *          100.000.000. for 100 Mhz
  38 * NOTE:
  39 *   This functions should be used by the hardware driver to get the correct
  40 *   frequency of the CPU. Don't use the macros, which are set to init the CPU
  41 *   frequency in the ROM code.
  42 */
  43 uint incaip_get_cpuclk(void)
  44 {
  45    /*-------------------------------------------------------------------------*/
  46    /* CPU Clock Input Multiplexer (MUX I)                                     */
  47    /* Multiplexer MUX I selects the maximum input clock to the CPU.           */
  48    /*-------------------------------------------------------------------------*/
  49    if (*((volatile ulong*)INCA_IP_CGU_CGU_MUXCR) & INCA_IP_CGU_CGU_MUXCR_MUXI)
  50    {
  51       /* MUX I set to 150 MHz clock */
  52       return 150000000;
  53    }
  54    else
  55    {
  56       /* MUX I set to 100/133 MHz clock */
  57       if (*((volatile ulong*)INCA_IP_CGU_CGU_DIVCR) & 0x40)
  58       {
  59          /* Division value is 1/3, maximum CPU operating */
  60          /* frequency is 133.3 MHz                       */
  61          return 130000000;
  62       }
  63       else
  64       {
  65          /* Division value is 1/4, maximum CPU operating */
  66          /* frequency is 100 MHz                         */
  67          return 100000000;
  68       }
  69    }
  70 }
  71
  72 /*******************************************************************************
  73 *
  74 * get_fpiclk - returns the frequency of the FPI bus.
  75 *
  76 * Gets the value directly from the INCA-IP hardware.
  77 *
  78 * RETURNS: Frquency in Hz
  79 *
  80 * NOTE:
  81 *   This functions should be used by the hardware driver to get the correct
  82 *   frequency of the CPU. Don't use the macros, which are set to init the CPU
  83 *   frequency in the ROM code.
  84 *   The calculation for the
  85 */
  86 uint incaip_get_fpiclk(void)
  87 {
  88    uint  clkCPU;
  89
  90    clkCPU = incaip_get_cpuclk();
  91
  92    switch (*((volatile ulong*)INCA_IP_CGU_CGU_DIVCR) & 0xC)
  93    {
  94       case 0x4:
  95          return clkCPU >> 1; /* devided by 2 */
  96          break;
  97       case 0x8:
  98          return clkCPU >> 2; /* devided by 4 */
  99          break;
 100       default:
 101          return clkCPU;
 102          break;
 103    }
 104 }