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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 <stdlib.h>
#include <system.h>
static unsigned int tlb_addr;
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 void set_section_dcache(int section, enum dcache_option option)
{
u32 value = section << MMU_SECTION_SHIFT | (3 << 10);
u32 *page_table;
unsigned int tlb_size = 4096 * 4;
/*
* FIXME(dhendrix): This calculation is from arch/arm/lib/board.c
* in u-boot. We may need to subtract more due to logging.
*/
tlb_addr = (CONFIG_SYS_SDRAM_BASE + (CONFIG_DRAM_SIZE_MB << 20UL));
tlb_addr -= tlb_size;
/* round down to next 64KB limit */
tlb_addr &= ~(0x10000 - 1);
page_table = (u32 *)tlb_addr;
switch (option) {
case DCACHE_WRITETHROUGH:
value |= 0x1a;
break;
case DCACHE_WRITEBACK:
value |= 0x1e;
break;
case DCACHE_OFF:
value |= 0x12;
break;
}
page_table[section] = value;
}
#if 0
void __mmu_page_table_flush(unsigned long start, unsigned long stop)
{
debug("%s: Warning: not implemented\n", __func__);
}
#endif
void mmu_set_region_dcache(unsigned long start, int size, enum dcache_option option)
{
u32 *page_table = &tlb_addr;
u32 upto, end;
end = ALIGN(start + size, MMU_SECTION_SIZE) >> MMU_SECTION_SHIFT;
start = start >> MMU_SECTION_SHIFT;
debug("mmu_set_region_dcache start=%x, size=%x, option=%d\n",
start, size, option);
for (upto = start; upto < end; upto++)
set_section_dcache(upto, option);
mmu_page_table_flush((u32)&page_table[start], (u32)&page_table[end]);
}
/**
* dram_bank_mmu_set - set up the data cache policy for a given dram bank
*
* @start: virtual address start of bank
* @size: size of bank (in bytes)
*/
static inline void dram_bank_mmu_setup(unsigned long start, unsigned long size)
{
int i;
debug("%s: bank: %d\n", __func__, bank);
for (i = start >> 20; i < (start + size) >> 20; i++) {
#if defined(CONFIG_ARM_DCACHE_POLICY_WRITEBACK)
set_section_dcache(i, DCACHE_WRITEBACK);
#elif defined(CONFIG_ARM_DCACHE_POLICY_WRITETHROUGH)
set_section_dcache(i, DCACHE_WRITETHROUGH);
#else
#error "Must define dcache policy."
#endif
}
}
/* to activate the MMU we need to set up virtual memory: use 1M areas */
inline void mmu_setup(unsigned long start, unsigned long size_mb)
{
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++)
set_section_dcache(i, DCACHE_OFF);
dram_bank_mmu_setup(start, size_mb << 20);
/* Copy the page table address to cp15 */
asm volatile("mcr p15, 0, %0, c2, c0, 0"
: : "r" (tlb_addr) : "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(unsigned long start, unsigned long size, 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(start, size);
reg = get_cr(); /* get control reg. */
cp_delay();
set_cr(reg | cache_bit);
}
/*
* Big hack warning!
*
* Devs like to compile with -O0 to get a nice debugging illusion. But this
* function does not survive that since -O0 causes the compiler to read the
* PC back from the stack after the dcache flush. Might it be possible to fix
* this by flushing the write buffer?
*/
static void cache_disable(uint32_t cache_bit) __attribute__ ((optimize(2)));
/* cache_bit must be either CR_I or CR_C */
static void cache_disable(uint32_t cache_bit)
{
uint32_t reg;
if (cache_bit == CR_C) {
/* if cache isn;t enabled no need to disable */
reg = get_cr();
if ((reg & CR_C) != CR_C)
return;
/* if disabling data cache, disable mmu too */
cache_bit |= CR_M;
}
reg = get_cr();
cp_delay();
if (cache_bit == (CR_C | CR_M))
flush_dcache_all();
set_cr(reg & ~cache_bit);
}
void icache_enable(unsigned long start, unsigned long size)
{
cache_enable(start, size, CR_I);
}
void icache_disable(void)
{
cache_disable(CR_I);
}
int icache_status(void)
{
return (get_cr() & CR_I) != 0;
}
void dcache_enable(unsigned long start, unsigned long size)
{
cache_enable(start, size, CR_C);
}
void dcache_disable(void)
{
cache_disable(CR_C);
}
int dcache_status(void)
{
return (get_cr() & CR_C) != 0;
}
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