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-rw-r--r--arch/arm/mach-mx2/cpu_imx27.c63
1 files changed, 63 insertions, 0 deletions
diff --git a/arch/arm/mach-mx2/cpu_imx27.c b/arch/arm/mach-mx2/cpu_imx27.c
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1/*
2 * Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
3 * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version 2
8 * of the License, or (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
17 * MA 02110-1301, USA.
18 */
19
20/*
21 * i.MX27 specific CPU detection code
22 */
23
24#include <linux/io.h>
25#include <linux/module.h>
26
27#include <asm/hardware.h>
28
29#include "crm_regs.h"
30
31static int cpu_silicon_rev = -1;
32static int cpu_partnumber;
33
34static void query_silicon_parameter(void)
35{
36 u32 val;
37 /*
38 * now we have access to the IO registers. As we need
39 * the silicon revision very early we read it here to
40 * avoid any further hooks
41 */
42 val = __raw_readl(IO_ADDRESS(SYSCTRL_BASE_ADDR) + SYS_CHIP_ID);
43
44 cpu_silicon_rev = (int)(val >> 28);
45 cpu_partnumber = (int)((val >> 12) & 0xFFFF);
46}
47
48/*
49 * Returns:
50 * the silicon revision of the cpu
51 * -EINVAL - not a mx27
52 */
53int mx27_revision(void)
54{
55 if (cpu_silicon_rev == -1)
56 query_silicon_parameter();
57
58 if (cpu_partnumber != 0x8821)
59 return -EINVAL;
60
61 return cpu_silicon_rev;
62}
63EXPORT_SYMBOL(mx27_revision);