arch/x86/cpu/sc520/sc520.c

   1 /*
   2  * (C) Copyright 2008-2011
   3  * Graeme Russ, <graeme.russ@gmail.com>
   4  *
   5  * (C) Copyright 2002
   6  * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
   7  *
   8  * See file CREDITS for list of people who contributed to this
   9  * project.
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation; either version 2 of
  14  * the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  24  * MA 02111-1307 USA
  25  */
  26
  27 #include <common.h>
  28 #include <asm/io.h>
  29 #include <asm/processor-flags.h>
  30 #include <asm/ic/sc520.h>
  31
  32 DECLARE_GLOBAL_DATA_PTR;
  33
  34 sc520_mmcr_t *sc520_mmcr = (sc520_mmcr_t *)SC520_MMCR_BASE;
  35
  36 int cpu_init_f(void)
  37 {
  38         if (CONFIG_SYS_SC520_HIGH_SPEED) {
  39                 /* set it to 133 MHz and write back */
  40                 writeb(0x02, &sc520_mmcr->cpuctl);
  41                 gd->cpu_clk = 133000000;
  42         } else {
  43                 /* set it to 100 MHz and write back */
  44                 writeb(0x01, &sc520_mmcr->cpuctl);
  45                 gd->cpu_clk = 100000000;
  46         }
  47
  48         /* wait at least one millisecond */
  49         asm("movl       $0x2000, %%ecx\n"
  50             "0:         pushl %%ecx\n"
  51             "popl       %%ecx\n"
  52             "loop 0b\n": : : "ecx");
  53
  54         return x86_cpu_init_f();
  55 }
  56
  57 int cpu_init_r(void)
  58 {
  59         /* Disable the PAR used for CAR */
  60         writel(0x0000000, &sc520_mmcr->par[2]);
  61
  62         /* turn on the SDRAM write buffer */
  63         writeb(0x11, &sc520_mmcr->dbctl);
  64
  65         return x86_cpu_init_r();
  66 }