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/*
* cpu.c - A few helper functions for ARM
*
* Copyright (c) 2007 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
*
* 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 version 2
* as published by the Free Software Foundation.
*
* 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
*/
/**
* @file
* @brief A few helper functions for ARM
*/
#include <common.h>
#include <command.h>
#include <cache.h>
#include <asm/mmu.h>
#include <asm/system.h>
#include <asm/memory.h>
/**
* Enable processor's instruction cache
*/
void icache_enable(void)
{
u32 r;
r = get_cr();
r |= CR_I;
set_cr(r);
}
/**
* Disable processor's instruction cache
*/
void icache_disable(void)
{
u32 r;
r = get_cr();
r &= ~CR_I;
set_cr(r);
}
/**
* Detect processor's current instruction cache status
* @return 0=disabled, 1=enabled
*/
int icache_status(void)
{
return (get_cr () & CR_I) != 0;
}
/**
* Disable MMU and D-cache, flush caches
* @return 0 (always)
*
* This function is called by shutdown_barebox to get a clean
* memory/cache state.
*/
void arch_shutdown(void)
{
#ifdef CONFIG_MMU
/* nearly the same as below, but this could also disable
* second level cache.
*/
mmu_disable();
#else
asm volatile (
"bl __mmu_cache_flush;"
"bl __mmu_cache_off;"
:
:
: "r0", "r1", "r2", "r3", "r6", "r10", "r12", "cc", "memory"
);
#endif
}
/**
* @page arm_boot_preparation Linux Preparation on ARM
*
* For ARM we never enable data cache so we do not need to disable it again.
* Linux can be called with instruction cache enabled. As this is the
* default setting we are running in barebox, there's no special preparation
* required.
*/
#ifdef CONFIG_COMMAND
static int do_icache(struct command *cmdtp, int argc, char *argv[])
{
if (argc == 1) {
printf("icache is %sabled\n", icache_status() ? "en" : "dis");
return 0;
}
if (simple_strtoul(argv[1], NULL, 0) > 0)
icache_enable();
else
icache_disable();
return 0;
}
static const __maybe_unused char cmd_icache_help[] =
"Usage: icache [0|1]\n";
BAREBOX_CMD_START(icache)
.cmd = do_icache,
.usage = "show/change icache status",
BAREBOX_CMD_HELP(cmd_icache_help)
BAREBOX_CMD_END
#endif
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