Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *      Implement 'Simple Boot Flag Specification 2.0'

 */

#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);