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/*
* (C) Copyright 2002
* Wolfgang Denk, DENX Software Engineering, wd@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
*/
#include <common.h>
#include <asm/system.h>
#if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF))
#if defined(CONFIG_SYS_ARM_CACHE_WRITETHROUGH)
#define CACHE_SETUP 0x1a
#else
#define CACHE_SETUP 0x1e
#endif
DECLARE_GLOBAL_DATA_PTR;
void __arm_init_before_mmu(void)
{
}
void arm_init_before_mmu(void)
__attribute__((weak, alias("__arm_init_before_mmu")));
static void cp_delay (void)
{
volatile int i;
/* copro seems to need some delay between reading and writing */
for (i = 0; i < 100; i++)
nop();
asm volatile("" : : : "memory");
}
static inline void dram_bank_mmu_setup(int bank)
{
u32 *page_table = (u32 *)gd->tlb_addr;
bd_t *bd = gd->bd;
int i;
debug("%s: bank: %d\n", __func__, bank);
for (i = bd->bi_dram[bank].start >> 20;
i < (bd->bi_dram[bank].start + bd->bi_dram[bank].size) >> 20;
i++) {
page_table[i] = i << 20 | (3 << 10) | CACHE_SETUP;
}
}
/* to activate the MMU we need to set up virtual memory: use 1M areas */
static inline void mmu_setup(void)
{
u32 *page_table = (u32 *)gd->tlb_addr;
int i;
u32 reg;
arm_init_before_mmu();
/* Set up an identity-mapping for all 4GB, rw for everyone */
for (i = 0; i < 4096; i++)
page_table[i] = i << 20 | (3 << 10) | 0x12;
for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
dram_bank_mmu_setup(i);
}
/* Copy the page table address to cp15 */
asm volatile("mcr p15, 0, %0, c2, c0, 0"
: : "r" (page_table) : "memory");
/* Set the access control to all-supervisor */
asm volatile("mcr p15, 0, %0, c3, c0, 0"
: : "r" (~0));
/* and enable the mmu */
reg = get_cr(); /* get control reg. */
cp_delay();
set_cr(reg | CR_M);
}
static int mmu_enabled(void)
{
return get_cr() & CR_M;
}
/* cache_bit must be either CR_I or CR_C */
static void cache_enable(uint32_t cache_bit)
{
uint32_t reg;
/* The data cache is not active unless the mmu is enabled too */
if ((cache_bit == CR_C) && !mmu_enabled())
mmu_setup();
reg = get_cr(); /* get control reg. */
cp_delay();
set_cr(reg | cache_bit);
}
/* cache_bit must be either CR_I or CR_C */
static void cache_disable(uint32_t cache_bit)
{
uint32_t reg;
reg = get_cr();
cp_delay();
if (cache_bit == CR_C) {
/* if cache isn;t enabled no need to disable */
if ((reg & CR_C) != CR_C)
return;
/* if disabling data cache, disable mmu too */
cache_bit |= CR_M;
flush_dcache_all();
}
set_cr(reg & ~cache_bit);
}
#endif
#ifdef CONFIG_SYS_ICACHE_OFF
void icache_enable (void)
{
return;
}
void icache_disable (void)
{
return;
}
int icache_status (void)
{
return 0; /* always off */
}
#else
void icache_enable(void)
{
cache_enable(CR_I);
}
void icache_disable(void)
{
cache_disable(CR_I);
}
int icache_status(void)
{
return (get_cr() & CR_I) != 0;
}
#endif
#ifdef CONFIG_SYS_DCACHE_OFF
void dcache_enable (void)
{
return;
}
void dcache_disable (void)
{
return;
}
int dcache_status (void)
{
return 0; /* always off */
}
#else
void dcache_enable(void)
{
cache_enable(CR_C);
}
void dcache_disable(void)
{
cache_disable(CR_C);
}
int dcache_status(void)
{
return (get_cr() & CR_C) != 0;
}
#endif
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