cpu/arm1136/cpu.c

   1 /*
   2  * (C) Copyright 2004 Texas Insturments
   3  *
   4  * (C) Copyright 2002
   5  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   6  * Marius Groeger <mgroeger@sysgo.de>
   7  *
   8  * (C) Copyright 2002
   9  * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
  10  *
  11  * See file CREDITS for list of people who contributed to this
  12  * project.
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License as
  16  * published by the Free Software Foundation; either version 2 of
  17  * the License, or (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  27  * MA 02111-1307 USA
  28  */
  29
  30 /*
  31  * CPU specific code
  32  */
  33
  34 #include <common.h>
  35 #include <command.h>
  36
  37 #ifdef CONFIG_USE_IRQ
  38 DECLARE_GLOBAL_DATA_PTR;
  39 #endif
  40
  41 /* read co-processor 15, register #1 (control register) */
  42 static unsigned long read_p15_c1 (void)
  43 {
  44         unsigned long value;
  45
  46         __asm__ __volatile__(
  47                                 "mrc    p15, 0, %0, c1, c0, 0   @ read control reg\n"
  48                                 : "=r" (value)
  49                                 :
  50                                 : "memory");
  51         return value;
  52 }
  53
  54 /* write to co-processor 15, register #1 (control register) */
  55 static void write_p15_c1 (unsigned long value)
  56 {
  57         __asm__ __volatile__(
  58                                                 "mcr    p15, 0, %0, c1, c0, 0   @ write it back\n"
  59                                                 :
  60                                                 : "r" (value)
  61                                                 : "memory");
  62
  63         read_p15_c1 ();
  64 }
  65
  66 static void cp_delay (void)
  67 {
  68         volatile int i;
  69
  70         /* Many OMAP regs need at least 2 nops  */
  71         for (i = 0; i < 100; i++);
  72 }
  73
  74 /* See also ARM Ref. Man. */
  75 #define C1_MMU          (1<<0)          /* mmu off/on */
  76 #define C1_ALIGN        (1<<1)          /* alignment faults off/on */
  77 #define C1_DC           (1<<2)          /* dcache off/on */
  78 #define C1_WB           (1<<3)          /* merging write buffer on/off */
  79 #define C1_BIG_ENDIAN   (1<<7)  /* big endian off/on */
  80 #define C1_SYS_PROT     (1<<8)          /* system protection */
  81 #define C1_ROM_PROT     (1<<9)          /* ROM protection */
  82 #define C1_IC           (1<<12)         /* icache off/on */
  83 #define C1_HIGH_VECTORS (1<<13) /* location of vectors: low/high addresses */
  84 #define RESERVED_1      (0xf << 3)      /* must be 111b for R/W */
  85
  86 int cpu_init (void)
  87 {
  88         /*
  89          * setup up stacks if necessary
  90          */
  91 #ifdef CONFIG_USE_IRQ
  92         IRQ_STACK_START = _armboot_start - CONFIG_SYS_MALLOC_LEN - CONFIG_SYS_GBL_DATA_SIZE - 4;
  93         FIQ_STACK_START = IRQ_STACK_START - CONFIG_STACKSIZE_IRQ;
  94 #endif
  95         return 0;
  96 }
  97
  98 int cleanup_before_linux (void)
  99 {
 100         /*
 101          * this function is called just before we call linux
 102          * it prepares the processor for linux
 103          *
 104          * we turn off caches etc ...
 105          */
 106
 107         unsigned long i;
 108
 109         disable_interrupts ();
 110
 111 #ifdef CONFIG_LCD
 112         {
 113                 extern void lcd_disable(void);
 114                 extern void lcd_panel_disable(void);
 115
 116                 lcd_disable(); /* proper disable of lcd & panel */
 117                 lcd_panel_disable();
 118         }
 119 #endif
 120
 121         /* turn off I/D-cache */
 122         asm ("mrc p15, 0, %0, c1, c0, 0":"=r" (i));
 123         i &= ~(C1_DC | C1_IC);
 124         asm ("mcr p15, 0, %0, c1, c0, 0": :"r" (i));
 125
 126         /* flush I/D-cache */
 127         i = 0;
 128         asm ("mcr p15, 0, %0, c7, c7, 0": :"r" (i));  /* invalidate both caches and flush btb */
 129         asm ("mcr p15, 0, %0, c7, c10, 4": :"r" (i)); /* mem barrier to sync things */
 130         return(0);
 131 }
 132
 133 int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 134 {
 135         disable_interrupts ();
 136         reset_cpu (0);
 137         /*NOTREACHED*/
 138         return(0);
 139 }
 140
 141 void icache_enable (void)
 142 {
 143         ulong reg;
 144
 145         reg = read_p15_c1 ();   /* get control reg. */
 146         cp_delay ();
 147         write_p15_c1 (reg | C1_IC);
 148 }
 149
 150 void icache_disable (void)
 151 {
 152         ulong reg;
 153
 154         reg = read_p15_c1 ();
 155         cp_delay ();
 156         write_p15_c1 (reg & ~C1_IC);
 157 }
 158
 159 int icache_status (void)
 160 {
 161         return(read_p15_c1 () & C1_IC) != 0;
 162 }