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/*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Marius Groeger <mgroeger@sysgo.de>
*
* (C) Copyright 2002
* Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/*
* CPU specific code
*/
#include <common.h>
#include <command.h>
#include <arm920t.h>
/* read co-processor 15, register #1 (control register) */
static unsigned long read_p15_c1 (void)
{
unsigned long value;
__asm__ __volatile__(
"mrc p15, 0, %0, c1, c0, 0 @ read control reg\n"
: "=r" (value)
:
: "memory");
#ifdef MMU_DEBUG
printf ("p15/c1 is = %08lx\n", value);
#endif
return value;
}
/* write to co-processor 15, register #1 (control register) */
static void write_p15_c1 (unsigned long value)
{
#ifdef MMU_DEBUG
printf ("write %08lx to p15/c1\n", value);
#endif
__asm__ __volatile__(
"mcr p15, 0, %0, c1, c0, 0 @ write it back\n"
:
: "r" (value)
: "memory");
read_p15_c1 ();
}
static void cp_delay (void)
{
volatile int i;
/* copro seems to need some delay between reading and writing */
for (i = 0; i < 100; i++);
}
/* See also ARM Ref. Man. */
#define C1_MMU (1<<0) /* mmu off/on */
#define C1_ALIGN (1<<1) /* alignment faults off/on */
#define C1_DC (1<<2) /* dcache off/on */
#define C1_BIG_ENDIAN (1<<7) /* big endian off/on */
#define C1_SYS_PROT (1<<8) /* system protection */
#define C1_ROM_PROT (1<<9) /* ROM protection */
#define C1_IC (1<<12) /* icache off/on */
#define C1_HIGH_VECTORS (1<<13) /* location of vectors: low/high addresses */
#define RESERVED_1 (0xf << 3) /* must be 111b for R/W */
int cpu_init (void)
{
/*
* setup up stacks if necessary
*/
#ifdef CONFIG_USE_IRQ
DECLARE_GLOBAL_DATA_PTR;
IRQ_STACK_START = _armboot_start - CFG_MALLOC_LEN - CFG_GBL_DATA_LEN - 4;
FIQ_STACK_START = IRQ_STACK_START - CONFIG_STACKSIZE_IRQ;
#endif
return 0;
}
int cleanup_before_linux (void)
{
/*
* this function is called just before we call linux
* it prepares the processor for linux
*
* we turn off caches etc ...
*/
unsigned long i;
disable_interrupts ();
/* turn off I/D-cache */
asm ("mrc p15, 0, %0, c1, c0, 0":"=r" (i));
i &= ~(C1_DC | C1_IC);
asm ("mcr p15, 0, %0, c1, c0, 0": :"r" (i));
/* flush I/D-cache */
i = 0;
asm ("mcr p15, 0, %0, c7, c7, 0": :"r" (i));
return (0);
}
int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
{
extern void reset_cpu (ulong addr);
disable_interrupts ();
reset_cpu (0);
/*NOTREACHED*/
return (0);
}
void icache_enable (void)
{
ulong reg;
reg = read_p15_c1 ();
cp_delay ();
write_p15_c1 (reg | C1_IC);
}
void icache_disable (void)
{
ulong reg;
reg = read_p15_c1 ();
cp_delay ();
write_p15_c1 (reg & ~C1_IC);
}
int icache_status (void)
{
return (read_p15_c1 () & C1_IC) != 0;
}
#ifdef USE_920T_MMU
/* It makes no sense to use the dcache if the MMU is not enabled */
void dcache_enable (void)
{
ulong reg;
reg = read_p15_c1 ();
cp_delay ();
write_p15_c1 (reg | C1_DC);
}
void dcache_disable (void)
{
ulong reg;
reg = read_p15_c1 ();
cp_delay ();
reg &= ~C1_DC;
write_p15_c1 (reg);
}
int dcache_status (void)
{
return (read_p15_c1 () & C1_DC) != 0;
}
#endif
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