[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / x86 / kernel / bootflag.c

/*
 *	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/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)
{
	unsigned long flags;
	u8 v;

	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);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Implement 'Simple Boot Flag Specification 2.0'
	3	*/
1da177e4 LT	4	#include <linux/types.h>
	5	#include <linux/kernel.h>
	6	#include <linux/init.h>
	7	#include <linux/string.h>
1da177e4 LT	8	#include <linux/spinlock.h>
	9	#include <linux/acpi.h>
	10	#include <asm/io.h>
	11
	12	#include <linux/mc146818rtc.h>
	13
1da177e4 LT	14	#define SBF_RESERVED (0x78)
	15	#define SBF_PNPOS (1<<0)
	16	#define SBF_BOOTING (1<<1)
	17	#define SBF_DIAG (1<<2)
	18	#define SBF_PARITY (1<<7)
	19
1da177e4 LT	20	int sbf_port __initdata = -1; /* set via acpi_boot_init() */
1da177e4 LT	21
1da177e4 LT	22	static int __init parity(u8 v)
	23	{
	24	int x = 0;
	25	int i;
8eed9260 CG	26
	27	for (i = 0; i < 8; i++) {
	28	x ^= (v & 1);
	29	v >>= 1;
1da177e4	30	}
8eed9260	31
1da177e4 LT	32	return x;
	33	}
	34
	35	static void __init sbf_write(u8 v)
	36	{
	37	unsigned long flags;
8eed9260 CG	38
8eed9260 CG	39	if (sbf_port != -1) {
1da177e4	40	v &= ~SBF_PARITY;
8eed9260 CG	41	if (!parity(v))
8eed9260 CG	42	v \|= SBF_PARITY;
1da177e4	43
8eed9260 CG	44	printk(KERN_INFO "Simple Boot Flag at 0x%x set to 0x%x\n",
8eed9260 CG	45	sbf_port, v);
1da177e4 LT	46
	47	spin_lock_irqsave(&rtc_lock, flags);
	48	CMOS_WRITE(v, sbf_port);
	49	spin_unlock_irqrestore(&rtc_lock, flags);
	50	}
	51	}
	52
	53	static u8 __init sbf_read(void)
	54	{
1da177e4	55	unsigned long flags;
8eed9260 CG	56	u8 v;
	57
	58	if (sbf_port == -1)
1da177e4	59	return 0;
8eed9260	60
1da177e4 LT	61	spin_lock_irqsave(&rtc_lock, flags);
	62	v = CMOS_READ(sbf_port);
	63	spin_unlock_irqrestore(&rtc_lock, flags);
8eed9260	64
1da177e4 LT	65	return v;
	66	}
	67
	68	static int __init sbf_value_valid(u8 v)
	69	{
8eed9260	70	if (v & SBF_RESERVED) /* Reserved bits */
1da177e4	71	return 0;
8eed9260	72	if (!parity(v))
1da177e4	73	return 0;
8eed9260	74
1da177e4 LT	75	return 1;
	76	}
	77
	78	static int __init sbf_init(void)
	79	{
	80	u8 v;
8eed9260 CG	81
8eed9260 CG	82	if (sbf_port == -1)
1da177e4	83	return 0;
8eed9260	84
1da177e4	85	v = sbf_read();
8eed9260 CG	86	if (!sbf_value_valid(v)) {
	87	printk(KERN_WARNING "Simple Boot Flag value 0x%x read from "
	88	"CMOS RAM was invalid\n", v);
	89	}
1da177e4 LT	90
	91	v &= ~SBF_RESERVED;
	92	v &= ~SBF_BOOTING;
	93	v &= ~SBF_DIAG;
	94	#if defined(CONFIG_ISAPNP)
	95	v \|= SBF_PNPOS;
	96	#endif
	97	sbf_write(v);
8eed9260	98
1da177e4 LT	99	return 0;
1da177e4 LT	100	}
1da177e4	101	module_init(sbf_init);