blob: 3b117be37bd2cd8cd6ce997ec294060045c44d11 [file] [log] [blame]
Juergen Beisertf31405c2008-07-05 10:02:59 +02001/*
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
Russell Kinga09e64f2008-08-05 16:14:15 +010027#include <mach/hardware.h>
Juergen Beisertf31405c2008-07-05 10:02:59 +020028
Juergen Beisertf31405c2008-07-05 10:02:59 +020029static int cpu_silicon_rev = -1;
30static int cpu_partnumber;
31
Sascha Haueredfcea82009-02-16 15:13:43 +010032#define SYS_CHIP_ID 0x00 /* The offset of CHIP ID register */
33
Juergen Beisertf31405c2008-07-05 10:02:59 +020034static 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 */
Uwe Kleine-Königbc9ea6c2009-12-16 17:30:27 +010042 val = __raw_readl(MX27_IO_ADDRESS(MX27_SYSCTRL_BASE_ADDR
43 + SYS_CHIP_ID));
Juergen Beisertf31405c2008-07-05 10:02:59 +020044
Dinh Nguyen9ab46502010-11-15 11:30:01 -060045 switch (val >> 28) {
46 case 0:
47 cpu_silicon_rev = IMX_CHIP_REVISION_1_0;
48 break;
49 case 1:
50 cpu_silicon_rev = IMX_CHIP_REVISION_2_0;
51 break;
52 case 2:
53 cpu_silicon_rev = IMX_CHIP_REVISION_2_1;
54 break;
55 default:
56 cpu_silicon_rev = IMX_CHIP_REVISION_UNKNOWN;
57 }
Juergen Beisertf31405c2008-07-05 10:02:59 +020058 cpu_partnumber = (int)((val >> 12) & 0xFFFF);
59}
60
61/*
62 * Returns:
63 * the silicon revision of the cpu
64 * -EINVAL - not a mx27
65 */
66int mx27_revision(void)
67{
68 if (cpu_silicon_rev == -1)
69 query_silicon_parameter();
70
71 if (cpu_partnumber != 0x8821)
72 return -EINVAL;
73
74 return cpu_silicon_rev;
75}
76EXPORT_SYMBOL(mx27_revision);