1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
100 lines
1.6 KiB
C
100 lines
1.6 KiB
C
/*
|
|
* Implement 'Simple Boot Flag Specification 2.0'
|
|
*/
|
|
|
|
|
|
#include <linux/config.h>
|
|
#include <linux/types.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/string.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/acpi.h>
|
|
#include <asm/io.h>
|
|
|
|
#include <linux/mc146818rtc.h>
|
|
|
|
|
|
#define SBF_RESERVED (0x78)
|
|
#define SBF_PNPOS (1<<0)
|
|
#define SBF_BOOTING (1<<1)
|
|
#define SBF_DIAG (1<<2)
|
|
#define SBF_PARITY (1<<7)
|
|
|
|
|
|
int sbf_port __initdata = -1; /* set via acpi_boot_init() */
|
|
|
|
|
|
static int __init parity(u8 v)
|
|
{
|
|
int x = 0;
|
|
int i;
|
|
|
|
for(i=0;i<8;i++)
|
|
{
|
|
x^=(v&1);
|
|
v>>=1;
|
|
}
|
|
return x;
|
|
}
|
|
|
|
static void __init sbf_write(u8 v)
|
|
{
|
|
unsigned long flags;
|
|
if(sbf_port != -1)
|
|
{
|
|
v &= ~SBF_PARITY;
|
|
if(!parity(v))
|
|
v|=SBF_PARITY;
|
|
|
|
printk(KERN_INFO "Simple Boot Flag at 0x%x set to 0x%x\n", sbf_port, v);
|
|
|
|
spin_lock_irqsave(&rtc_lock, flags);
|
|
CMOS_WRITE(v, sbf_port);
|
|
spin_unlock_irqrestore(&rtc_lock, flags);
|
|
}
|
|
}
|
|
|
|
static u8 __init sbf_read(void)
|
|
{
|
|
u8 v;
|
|
unsigned long flags;
|
|
if(sbf_port == -1)
|
|
return 0;
|
|
spin_lock_irqsave(&rtc_lock, flags);
|
|
v = CMOS_READ(sbf_port);
|
|
spin_unlock_irqrestore(&rtc_lock, flags);
|
|
return v;
|
|
}
|
|
|
|
static int __init sbf_value_valid(u8 v)
|
|
{
|
|
if(v&SBF_RESERVED) /* Reserved bits */
|
|
return 0;
|
|
if(!parity(v))
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
static int __init sbf_init(void)
|
|
{
|
|
u8 v;
|
|
if(sbf_port == -1)
|
|
return 0;
|
|
v = sbf_read();
|
|
if(!sbf_value_valid(v))
|
|
printk(KERN_WARNING "Simple Boot Flag value 0x%x read from CMOS RAM was invalid\n",v);
|
|
|
|
v &= ~SBF_RESERVED;
|
|
v &= ~SBF_BOOTING;
|
|
v &= ~SBF_DIAG;
|
|
#if defined(CONFIG_ISAPNP)
|
|
v |= SBF_PNPOS;
|
|
#endif
|
|
sbf_write(v);
|
|
return 0;
|
|
}
|
|
|
|
module_init(sbf_init);
|