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 *          133.333.333 for 133 Mhz (= 400MHz/3)
  37 *          100.000.000 for 100 Mhz (= 400MHz/4)
  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) &
  50             INCA_IP_CGU_CGU_MUXCR_MUXI) {
  51                 /* MUX I set to 150 MHz clock */
  52                 return 150000000;
  53         } else {
  54                 /* MUX I set to 100/133 MHz clock */
  55                 if (*((volatile ulong *) INCA_IP_CGU_CGU_DIVCR) & 0x40) {
  56                         /* Division value is 1/3, maximum CPU operating */
  57                         /* frequency is 133.3 MHz                       */
  58                         return 133333333;
  59                 } else {
  60                         /* Division value is 1/4, maximum CPU operating */
  61                         /* frequency is 100 MHz                         */
  62                         return 100000000;
  63                 }
  64         }
  65 }
  66
  67 /*******************************************************************************
  68 *
  69 * get_fpiclk - returns the frequency of the FPI bus.
  70 *
  71 * Gets the value directly from the INCA-IP hardware.
  72 *
  73 * RETURNS: Frquency in Hz
  74 *
  75 * NOTE:
  76 *   This functions should be used by the hardware driver to get the correct
  77 *   frequency of the CPU. Don't use the macros, which are set to init the CPU
  78 *   frequency in the ROM code.
  79 *   The calculation for the
  80 */
  81 uint incaip_get_fpiclk (void)
  82 {
  83         uint clkCPU;
  84
  85         clkCPU = incaip_get_cpuclk ();
  86
  87         switch (*((volatile ulong *) INCA_IP_CGU_CGU_DIVCR) & 0xC) {
  88         case 0x4:
  89                 return clkCPU >> 1;     /* devided by 2 */
  90                 break;
  91         case 0x8:
  92                 return clkCPU >> 2;     /* devided by 4 */
  93                 break;
  94         default:
  95                 return clkCPU;
  96                 break;
  97         }
  98 }
  99
 100 int incaip_set_cpuclk (void)
 101 {
 102         extern void ebu_init(long);
 103         extern void cgu_init(long);
 104         extern void sdram_init(long);
 105         char tmp[64];
 106         ulong cpuclk;
 107
 108         if (getenv_r ("cpuclk", tmp, sizeof (tmp)) > 0) {
 109                 cpuclk = simple_strtoul (tmp, NULL, 10) * 1000000;
 110                 cgu_init (cpuclk);
 111                 ebu_init (cpuclk);
 112                 sdram_init (cpuclk);
 113         }
 114
 115         return 0;
 116 }