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 *
  31 * get_cpuclk - returns the frequency of the CPU.
  32 *
  33 * Gets the value directly from the INCA-IP hardware.
  34 *
  35 * RETURNS:
  36 *          150.000.000 for 150 MHz
  37 *          130.000.000. for 130 Mhz
  38 *          100.000.000. for 100 Mhz
  39 * NOTE:
  40 *   This functions should be used by the hardware driver to get the correct
  41 *   frequency of the CPU. Don't use the macros, which are set to init the CPU
  42 *   frequency in the ROM code.
  43 */
  44 uint incaip_get_cpuclk(void)
  45 {
  46    /*-------------------------------------------------------------------------*/
  47    /* CPU Clock Input Multiplexer (MUX I)                                     */
  48    /* Multiplexer MUX I selects the maximum input clock to the CPU.           */
  49    /*-------------------------------------------------------------------------*/
  50    if (*((volatile ulong*)INCA_IP_CGU_CGU_MUXCR) & INCA_IP_CGU_CGU_MUXCR_MUXI)
  51    {
  52       /* MUX I set to 150 MHz clock */
  53       return 150000000;
  54    }
  55    else
  56    {
  57       /* MUX I set to 100/133 MHz clock */
  58       if (*((volatile ulong*)INCA_IP_CGU_CGU_DIVCR) & 0x40)
  59       {
  60          /* Division value is 1/3, maximum CPU operating */
  61          /* frequency is 133.3 MHz                       */
  62          return 130000000;
  63       }
  64       else
  65       {
  66          /* Division value is 1/4, maximum CPU operating */
  67          /* frequency is 100 MHz                         */
  68          return 100000000;
  69       }
  70    }
  71 }
  72
  73 /*******************************************************************************
  74 *
  75 * get_fpiclk - returns the frequency of the FPI bus.
  76 *
  77 * Gets the value directly from the INCA-IP hardware.
  78 *
  79 * RETURNS: Frquency in Hz
  80 *
  81 * NOTE:
  82 *   This functions should be used by the hardware driver to get the correct
  83 *   frequency of the CPU. Don't use the macros, which are set to init the CPU
  84 *   frequency in the ROM code.
  85 *   The calculation for the
  86 */
  87 uint incaip_get_fpiclk(void)
  88 {
  89    uint  clkCPU;
  90
  91    clkCPU = incaip_get_cpuclk();
  92
  93    switch (*((volatile ulong*)INCA_IP_CGU_CGU_DIVCR) & 0xC)
  94    {
  95       case 0x4:
  96          return clkCPU >> 1; /* devided by 2 */
  97          break;
  98       case 0x8:
  99          return clkCPU >> 2; /* devided by 4 */
 100          break;
 101       default:
 102          return clkCPU;
 103          break;
 104    }
 105 }
 106
 107