target/linux/ifxmips/image/u-boot/files/cpu/mips/danube/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 #ifdef CONFIG_INCA_IP
  25
  26 #include <common.h>
  27 #include <asm/inca-ip.h>
  28
  29
  30 /*******************************************************************************
  31 *
  32 * get_cpuclk - returns the frequency of the CPU.
  33 *
  34 * Gets the value directly from the INCA-IP hardware.
  35 *
  36 * RETURNS:
  37 *          150.000.000 for 150 MHz
  38 *          133.333.333 for 133 Mhz (= 400MHz/3)
  39 *          100.000.000 for 100 Mhz (= 400MHz/4)
  40 * NOTE:
  41 *   This functions should be used by the hardware driver to get the correct
  42 *   frequency of the CPU. Don't use the macros, which are set to init the CPU
  43 *   frequency in the ROM code.
  44 */
  45 uint incaip_get_cpuclk (void)
  46 {
  47         /*-------------------------------------------------------------------------*/
  48         /* CPU Clock Input Multiplexer (MUX I)                                     */
  49         /* Multiplexer MUX I selects the maximum input clock to the CPU.           */
  50         /*-------------------------------------------------------------------------*/
  51         if (*((volatile ulong *) INCA_IP_CGU_CGU_MUXCR) &
  52             INCA_IP_CGU_CGU_MUXCR_MUXI) {
  53                 /* MUX I set to 150 MHz clock */
  54                 return 150000000;
  55         } else {
  56                 /* MUX I set to 100/133 MHz clock */
  57                 if (*((volatile ulong *) INCA_IP_CGU_CGU_DIVCR) & 0x40) {
  58                         /* Division value is 1/3, maximum CPU operating */
  59                         /* frequency is 133.3 MHz                       */
  60                         return 133333333;
  61                 } else {
  62                         /* Division value is 1/4, maximum CPU operating */
  63                         /* frequency is 100 MHz                         */
  64                         return 100000000;
  65                 }
  66         }
  67 }
  68
  69 /*******************************************************************************
  70 *
  71 * get_fpiclk - returns the frequency of the FPI bus.
  72 *
  73 * Gets the value directly from the INCA-IP hardware.
  74 *
  75 * RETURNS: Frquency in Hz
  76 *
  77 * NOTE:
  78 *   This functions should be used by the hardware driver to get the correct
  79 *   frequency of the CPU. Don't use the macros, which are set to init the CPU
  80 *   frequency in the ROM code.
  81 *   The calculation for the
  82 */
  83 uint incaip_get_fpiclk (void)
  84 {
  85         uint clkCPU;
  86
  87         clkCPU = incaip_get_cpuclk ();
  88
  89         switch (*((volatile ulong *) INCA_IP_CGU_CGU_DIVCR) & 0xC) {
  90         case 0x4:
  91                 return clkCPU >> 1;     /* devided by 2 */
  92                 break;
  93         case 0x8:
  94                 return clkCPU >> 2;     /* devided by 4 */
  95                 break;
  96         default:
  97                 return clkCPU;
  98                 break;
  99         }
 100 }
 101
 102 int incaip_set_cpuclk (void)
 103 {
 104         extern void ebu_init(long);
 105         extern void cgu_init(long);
 106         extern void sdram_init(long);
 107         char tmp[64];
 108         ulong cpuclk;
 109
 110         if (getenv_r ("cpuclk", tmp, sizeof (tmp)) > 0) {
 111                 cpuclk = simple_strtoul (tmp, NULL, 10) * 1000000;
 112                 cgu_init (cpuclk);
 113                 ebu_init (cpuclk);
 114                 sdram_init (cpuclk);
 115         }
 116
 117         return 0;
 118 }
 119
 120 #endif /* CONFIG_INCA_IP */