1 // SPDX-License-Identifier: GPL-2.0-or-later 1
2 /*
3 * Copyright 2007 Freescale Semiconductor, Inc
4 * Copyright 2008 Juergen Beisert, kernel@peng
5 */
6
7 /*
8 * i.MX27 specific CPU detection code
9 */
10
11 #include <linux/io.h>
12 #include <linux/of_address.h>
13 #include <linux/module.h>
14
15 #include "hardware.h"
16
17 static int mx27_cpu_rev = -1;
18 static int mx27_cpu_partnumber;
19
20 #define SYS_CHIP_ID 0x00 /* The
21 #define SYSCTRL_OFFSET 0x800 /* Off
22
23 static int mx27_read_cpu_rev(void)
24 {
25 void __iomem *ccm_base;
26 struct device_node *np;
27 u32 val;
28
29 np = of_find_compatible_node(NULL, NUL
30 ccm_base = of_iomap(np, 0);
31 of_node_put(np);
32 BUG_ON(!ccm_base);
33 /*
34 * now we have access to the IO regist
35 * the silicon revision very early we
36 * avoid any further hooks
37 */
38 val = imx_readl(ccm_base + SYSCTRL_OFF
39
40 mx27_cpu_partnumber = (int)((val >> 12
41
42 switch (val >> 28) {
43 case 0:
44 return IMX_CHIP_REVISION_1_0;
45 case 1:
46 return IMX_CHIP_REVISION_2_0;
47 case 2:
48 return IMX_CHIP_REVISION_2_1;
49 default:
50 return IMX_CHIP_REVISION_UNKNO
51 }
52 }
53
54 /*
55 * Returns:
56 * the silicon revision of the cpu
57 * -EINVAL - not a mx27
58 */
59 int mx27_revision(void)
60 {
61 if (mx27_cpu_rev == -1)
62 mx27_cpu_rev = mx27_read_cpu_r
63
64 if (mx27_cpu_partnumber != 0x8821)
65 return -EINVAL;
66
67 return mx27_cpu_rev;
68 }
69 EXPORT_SYMBOL(mx27_revision);
70
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.