diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2007-10-11 05:17:01 -0400 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2007-10-11 05:17:01 -0400 |
commit | 9a163ed8e0552fdcffe405d2ea7134819a81456e (patch) | |
tree | b322fd2afbb812ba7ddfd22f3734aaab007c2aa5 /arch/x86/kernel/bootflag.c | |
parent | f7627e2513987bb5d4e8cb13c4e0a478352141ac (diff) |
i386: move kernel
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/bootflag.c')
-rw-r--r-- | arch/x86/kernel/bootflag.c | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/arch/x86/kernel/bootflag.c b/arch/x86/kernel/bootflag.c new file mode 100644 index 000000000000..0b9860530a6b --- /dev/null +++ b/arch/x86/kernel/bootflag.c | |||
@@ -0,0 +1,98 @@ | |||
1 | /* | ||
2 | * Implement 'Simple Boot Flag Specification 2.0' | ||
3 | */ | ||
4 | |||
5 | |||
6 | #include <linux/types.h> | ||
7 | #include <linux/kernel.h> | ||
8 | #include <linux/init.h> | ||
9 | #include <linux/string.h> | ||
10 | #include <linux/slab.h> | ||
11 | #include <linux/spinlock.h> | ||
12 | #include <linux/acpi.h> | ||
13 | #include <asm/io.h> | ||
14 | |||
15 | #include <linux/mc146818rtc.h> | ||
16 | |||
17 | |||
18 | #define SBF_RESERVED (0x78) | ||
19 | #define SBF_PNPOS (1<<0) | ||
20 | #define SBF_BOOTING (1<<1) | ||
21 | #define SBF_DIAG (1<<2) | ||
22 | #define SBF_PARITY (1<<7) | ||
23 | |||
24 | |||
25 | int sbf_port __initdata = -1; /* set via acpi_boot_init() */ | ||
26 | |||
27 | |||
28 | static int __init parity(u8 v) | ||
29 | { | ||
30 | int x = 0; | ||
31 | int i; | ||
32 | |||
33 | for(i=0;i<8;i++) | ||
34 | { | ||
35 | x^=(v&1); | ||
36 | v>>=1; | ||
37 | } | ||
38 | return x; | ||
39 | } | ||
40 | |||
41 | static void __init sbf_write(u8 v) | ||
42 | { | ||
43 | unsigned long flags; | ||
44 | if(sbf_port != -1) | ||
45 | { | ||
46 | v &= ~SBF_PARITY; | ||
47 | if(!parity(v)) | ||
48 | v|=SBF_PARITY; | ||
49 | |||
50 | printk(KERN_INFO "Simple Boot Flag at 0x%x set to 0x%x\n", sbf_port, v); | ||
51 | |||
52 | spin_lock_irqsave(&rtc_lock, flags); | ||
53 | CMOS_WRITE(v, sbf_port); | ||
54 | spin_unlock_irqrestore(&rtc_lock, flags); | ||
55 | } | ||
56 | } | ||
57 | |||
58 | static u8 __init sbf_read(void) | ||
59 | { | ||
60 | u8 v; | ||
61 | unsigned long flags; | ||
62 | if(sbf_port == -1) | ||
63 | return 0; | ||
64 | spin_lock_irqsave(&rtc_lock, flags); | ||
65 | v = CMOS_READ(sbf_port); | ||
66 | spin_unlock_irqrestore(&rtc_lock, flags); | ||
67 | return v; | ||
68 | } | ||
69 | |||
70 | static int __init sbf_value_valid(u8 v) | ||
71 | { | ||
72 | if(v&SBF_RESERVED) /* Reserved bits */ | ||
73 | return 0; | ||
74 | if(!parity(v)) | ||
75 | return 0; | ||
76 | return 1; | ||
77 | } | ||
78 | |||
79 | static int __init sbf_init(void) | ||
80 | { | ||
81 | u8 v; | ||
82 | if(sbf_port == -1) | ||
83 | return 0; | ||
84 | v = sbf_read(); | ||
85 | if(!sbf_value_valid(v)) | ||
86 | printk(KERN_WARNING "Simple Boot Flag value 0x%x read from CMOS RAM was invalid\n",v); | ||
87 | |||
88 | v &= ~SBF_RESERVED; | ||
89 | v &= ~SBF_BOOTING; | ||
90 | v &= ~SBF_DIAG; | ||
91 | #if defined(CONFIG_ISAPNP) | ||
92 | v |= SBF_PNPOS; | ||
93 | #endif | ||
94 | sbf_write(v); | ||
95 | return 0; | ||
96 | } | ||
97 | |||
98 | module_init(sbf_init); | ||