64 lines
1.7 KiB
C
64 lines
1.7 KiB
C
/*
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* Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
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* Copyright 2008 Juergen Beisert, kernel@pengutronix.de
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*/
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/*
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* i.MX27 specific CPU detection code
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*/
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#include <linux/io.h>
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#include <linux/module.h>
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#include <mach/hardware.h>
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static int cpu_silicon_rev = -1;
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static int cpu_partnumber;
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#define SYS_CHIP_ID 0x00 /* The offset of CHIP ID register */
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static void query_silicon_parameter(void)
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{
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u32 val;
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/*
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* now we have access to the IO registers. As we need
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* the silicon revision very early we read it here to
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* avoid any further hooks
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*/
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val = __raw_readl(IO_ADDRESS(SYSCTRL_BASE_ADDR) + SYS_CHIP_ID);
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cpu_silicon_rev = (int)(val >> 28);
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cpu_partnumber = (int)((val >> 12) & 0xFFFF);
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}
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/*
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* Returns:
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* the silicon revision of the cpu
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* -EINVAL - not a mx27
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*/
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int mx27_revision(void)
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{
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if (cpu_silicon_rev == -1)
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query_silicon_parameter();
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if (cpu_partnumber != 0x8821)
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return -EINVAL;
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return cpu_silicon_rev;
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}
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EXPORT_SYMBOL(mx27_revision);
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