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/*
* Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
* Copyright 2008 Juergen Beisert, kernel@pengutronix.de
*
* 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., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
/*
* i.MX27 specific CPU detection code
*/
#include <linux/io.h>
#include <linux/module.h>
#include <mach/hardware.h>
static int cpu_silicon_rev = -1;
static int cpu_partnumber;
#define SYS_CHIP_ID 0x00 /* The offset of CHIP ID register */
static void query_silicon_parameter(void)
{
u32 val;
/*
* now we have access to the IO registers. As we need
* the silicon revision very early we read it here to
* avoid any further hooks
*/
val = __raw_readl(MX27_IO_ADDRESS(MX27_SYSCTRL_BASE_ADDR
+ SYS_CHIP_ID));
cpu_silicon_rev = (int)(val >> 28);
cpu_partnumber = (int)((val >> 12) & 0xFFFF);
}
/*
* Returns:
* the silicon revision of the cpu
* -EINVAL - not a mx27
*/
int mx27_revision(void)
{
if (cpu_silicon_rev == -1)
query_silicon_parameter();
if (cpu_partnumber != 0x8821)
return -EINVAL;
return cpu_silicon_rev;
}
EXPORT_SYMBOL(mx27_revision);
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