[linux-2.6-block.git] / arch / x86 / kernel / hpet.c

#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/hpet.h>
#include <linux/init.h>
#include <linux/sysdev.h>
#include <linux/pm.h>
#include <linux/delay.h>

#include <asm/fixmap.h>
#include <asm/hpet.h>
#include <asm/i8253.h>
#include <asm/io.h>

#define HPET_MASK	CLOCKSOURCE_MASK(32)
#define HPET_SHIFT	22

/* FSEC = 10^-15 NSEC = 10^-9 */
#define FSEC_PER_NSEC	1000000

/*
 * HPET address is set in acpi/boot.c, when an ACPI entry exists
 */
unsigned long hpet_address;
static void __iomem *hpet_virt_address;

unsigned long hpet_readl(unsigned long a)
{
	return readl(hpet_virt_address + a);
}

static inline void hpet_writel(unsigned long d, unsigned long a)
{
	writel(d, hpet_virt_address + a);
}

#ifdef CONFIG_X86_64

#include <asm/pgtable.h>

static inline void hpet_set_mapping(void)
{
	set_fixmap_nocache(FIX_HPET_BASE, hpet_address);
	__set_fixmap(VSYSCALL_HPET, hpet_address, PAGE_KERNEL_VSYSCALL_NOCACHE);
	hpet_virt_address = (void __iomem *)fix_to_virt(FIX_HPET_BASE);
}

static inline void hpet_clear_mapping(void)
{
	hpet_virt_address = NULL;
}

#else

static inline void hpet_set_mapping(void)
{
	hpet_virt_address = ioremap_nocache(hpet_address, HPET_MMAP_SIZE);
}

static inline void hpet_clear_mapping(void)
{
	iounmap(hpet_virt_address);
	hpet_virt_address = NULL;
}
#endif

/*
 * HPET command line enable / disable
 */
static int boot_hpet_disable;

static int __init hpet_setup(char* str)
{
	if (str) {
		if (!strncmp("disable", str, 7))
			boot_hpet_disable = 1;
	}
	return 1;
}
__setup("hpet=", hpet_setup);

static int __init disable_hpet(char *str)
{
	boot_hpet_disable = 1;
	return 1;
}
__setup("nohpet", disable_hpet);

static inline int is_hpet_capable(void)
{
	return (!boot_hpet_disable && hpet_address);
}

/*
 * HPET timer interrupt enable / disable
 */
static int hpet_legacy_int_enabled;

/**
 * is_hpet_enabled - check whether the hpet timer interrupt is enabled
 */
int is_hpet_enabled(void)
{
	return is_hpet_capable() && hpet_legacy_int_enabled;
}

/*
 * When the hpet driver (/dev/hpet) is enabled, we need to reserve
 * timer 0 and timer 1 in case of RTC emulation.
 */
#ifdef CONFIG_HPET
static void hpet_reserve_platform_timers(unsigned long id)
{
	struct hpet __iomem *hpet = hpet_virt_address;
	struct hpet_timer __iomem *timer = &hpet->hpet_timers[2];
	unsigned int nrtimers, i;
	struct hpet_data hd;

	nrtimers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;

	memset(&hd, 0, sizeof (hd));
	hd.hd_phys_address = hpet_address;
	hd.hd_address = hpet;
	hd.hd_nirqs = nrtimers;
	hd.hd_flags = HPET_DATA_PLATFORM;
	hpet_reserve_timer(&hd, 0);

#ifdef CONFIG_HPET_EMULATE_RTC
	hpet_reserve_timer(&hd, 1);
#endif

	hd.hd_irq[0] = HPET_LEGACY_8254;
	hd.hd_irq[1] = HPET_LEGACY_RTC;

	for (i = 2; i < nrtimers; timer++, i++)
		hd.hd_irq[i] = (timer->hpet_config & Tn_INT_ROUTE_CNF_MASK) >>
			Tn_INT_ROUTE_CNF_SHIFT;

	hpet_alloc(&hd);

}
#else
static void hpet_reserve_platform_timers(unsigned long id) { }
#endif

/*
 * Common hpet info
 */
static unsigned long hpet_period;

static void hpet_legacy_set_mode(enum clock_event_mode mode,
			  struct clock_event_device *evt);
static int hpet_legacy_next_event(unsigned long delta,
			   struct clock_event_device *evt);

/*
 * The hpet clock event device
 */
static struct clock_event_device hpet_clockevent = {
	.name		= "hpet",
	.features	= CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
	.set_mode	= hpet_legacy_set_mode,
	.set_next_event = hpet_legacy_next_event,
	.shift		= 32,
	.irq		= 0,
};

static void hpet_start_counter(void)
{
	unsigned long cfg = hpet_readl(HPET_CFG);

	cfg &= ~HPET_CFG_ENABLE;
	hpet_writel(cfg, HPET_CFG);
	hpet_writel(0, HPET_COUNTER);
	hpet_writel(0, HPET_COUNTER + 4);
	cfg |= HPET_CFG_ENABLE;
	hpet_writel(cfg, HPET_CFG);
}

static void hpet_enable_legacy_int(void)
{
	unsigned long cfg = hpet_readl(HPET_CFG);

	cfg |= HPET_CFG_LEGACY;
	hpet_writel(cfg, HPET_CFG);
	hpet_legacy_int_enabled = 1;
}

static void hpet_legacy_clockevent_register(void)
{
	uint64_t hpet_freq;

	/* Start HPET legacy interrupts */
	hpet_enable_legacy_int();

	/*
	 * The period is a femto seconds value. We need to calculate the
	 * scaled math multiplication factor for nanosecond to hpet tick
	 * conversion.
	 */
	hpet_freq = 1000000000000000ULL;
	do_div(hpet_freq, hpet_period);
	hpet_clockevent.mult = div_sc((unsigned long) hpet_freq,
				      NSEC_PER_SEC, 32);
	/* Calculate the min / max delta */
	hpet_clockevent.max_delta_ns = clockevent_delta2ns(0x7FFFFFFF,
							   &hpet_clockevent);
	hpet_clockevent.min_delta_ns = clockevent_delta2ns(0x30,
							   &hpet_clockevent);

	/*
	 * Start hpet with the boot cpu mask and make it
	 * global after the IO_APIC has been initialized.
	 */
	hpet_clockevent.cpumask = cpumask_of_cpu(smp_processor_id());
	clockevents_register_device(&hpet_clockevent);
	global_clock_event = &hpet_clockevent;
	printk(KERN_DEBUG "hpet clockevent registered\n");
}

static void hpet_legacy_set_mode(enum clock_event_mode mode,
			  struct clock_event_device *evt)
{
	unsigned long cfg, cmp, now;
	uint64_t delta;

	switch(mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		delta = ((uint64_t)(NSEC_PER_SEC/HZ)) * hpet_clockevent.mult;
		delta >>= hpet_clockevent.shift;
		now = hpet_readl(HPET_COUNTER);
		cmp = now + (unsigned long) delta;
		cfg = hpet_readl(HPET_T0_CFG);
		cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC |
		       HPET_TN_SETVAL | HPET_TN_32BIT;
		hpet_writel(cfg, HPET_T0_CFG);
		/*
		 * The first write after writing TN_SETVAL to the
		 * config register sets the counter value, the second
		 * write sets the period.
		 */
		hpet_writel(cmp, HPET_T0_CMP);
		udelay(1);
		hpet_writel((unsigned long) delta, HPET_T0_CMP);
		break;

	case CLOCK_EVT_MODE_ONESHOT:
		cfg = hpet_readl(HPET_T0_CFG);
		cfg &= ~HPET_TN_PERIODIC;
		cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
		hpet_writel(cfg, HPET_T0_CFG);
		break;

	case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_SHUTDOWN:
		cfg = hpet_readl(HPET_T0_CFG);
		cfg &= ~HPET_TN_ENABLE;
		hpet_writel(cfg, HPET_T0_CFG);
		break;

	case CLOCK_EVT_MODE_RESUME:
		hpet_enable_legacy_int();
		break;
	}
}

static int hpet_legacy_next_event(unsigned long delta,
			   struct clock_event_device *evt)
{
	unsigned long cnt;

	cnt = hpet_readl(HPET_COUNTER);
	cnt += delta;
	hpet_writel(cnt, HPET_T0_CMP);

	return ((long)(hpet_readl(HPET_COUNTER) - cnt ) > 0) ? -ETIME : 0;
}

/*
 * Clock source related code
 */
static cycle_t read_hpet(void)
{
	return (cycle_t)hpet_readl(HPET_COUNTER);
}

#ifdef CONFIG_X86_64
static cycle_t __vsyscall_fn vread_hpet(void)
{
	return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + 0xf0);
}
#endif

static struct clocksource clocksource_hpet = {
	.name		= "hpet",
	.rating		= 250,
	.read		= read_hpet,
	.mask		= HPET_MASK,
	.shift		= HPET_SHIFT,
	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
	.resume		= hpet_start_counter,
#ifdef CONFIG_X86_64
	.vread		= vread_hpet,
#endif
};

static int hpet_clocksource_register(void)
{
	u64 tmp, start, now;
	cycle_t t1;

	/* Start the counter */
	hpet_start_counter();

	/* Verify whether hpet counter works */
	t1 = read_hpet();
	rdtscll(start);

	/*
	 * We don't know the TSC frequency yet, but waiting for
	 * 200000 TSC cycles is safe:
	 * 4 GHz == 50us
	 * 1 GHz == 200us
	 */
	do {
		rep_nop();
		rdtscll(now);
	} while ((now - start) < 200000UL);

	if (t1 == read_hpet()) {
		printk(KERN_WARNING
		       "HPET counter not counting. HPET disabled\n");
		return -ENODEV;
	}

	/* Initialize and register HPET clocksource
	 *
	 * hpet period is in femto seconds per cycle
	 * so we need to convert this to ns/cyc units
	 * aproximated by mult/2^shift
	 *
	 *  fsec/cyc * 1nsec/1000000fsec = nsec/cyc = mult/2^shift
	 *  fsec/cyc * 1ns/1000000fsec * 2^shift = mult
	 *  fsec/cyc * 2^shift * 1nsec/1000000fsec = mult
	 *  (fsec/cyc << shift)/1000000 = mult
	 *  (hpet_period << shift)/FSEC_PER_NSEC = mult
	 */
	tmp = (u64)hpet_period << HPET_SHIFT;
	do_div(tmp, FSEC_PER_NSEC);
	clocksource_hpet.mult = (u32)tmp;

	clocksource_register(&clocksource_hpet);

	return 0;
}

/*
 * Try to setup the HPET timer
 */
int __init hpet_enable(void)
{
	unsigned long id;

	if (!is_hpet_capable())
		return 0;

	hpet_set_mapping();

	/*
	 * Read the period and check for a sane value:
	 */
	hpet_period = hpet_readl(HPET_PERIOD);
	if (hpet_period < HPET_MIN_PERIOD || hpet_period > HPET_MAX_PERIOD)
		goto out_nohpet;

	/*
	 * Read the HPET ID register to retrieve the IRQ routing
	 * information and the number of channels
	 */
	id = hpet_readl(HPET_ID);

#ifdef CONFIG_HPET_EMULATE_RTC
	/*
	 * The legacy routing mode needs at least two channels, tick timer
	 * and the rtc emulation channel.
	 */
	if (!(id & HPET_ID_NUMBER))
		goto out_nohpet;
#endif

	if (hpet_clocksource_register())
		goto out_nohpet;

	if (id & HPET_ID_LEGSUP) {
		hpet_legacy_clockevent_register();
		return 1;
	}
	return 0;

out_nohpet:
	hpet_clear_mapping();
	boot_hpet_disable = 1;
	return 0;
}

/*
 * Needs to be late, as the reserve_timer code calls kalloc !
 *
 * Not a problem on i386 as hpet_enable is called from late_time_init,
 * but on x86_64 it is necessary !
 */
static __init int hpet_late_init(void)
{
	if (!is_hpet_capable())
		return -ENODEV;

	hpet_reserve_platform_timers(hpet_readl(HPET_ID));
	return 0;
}
fs_initcall(hpet_late_init);

#ifdef CONFIG_HPET_EMULATE_RTC

/* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET
 * is enabled, we support RTC interrupt functionality in software.
 * RTC has 3 kinds of interrupts:
 * 1) Update Interrupt - generate an interrupt, every sec, when RTC clock
 *    is updated
 * 2) Alarm Interrupt - generate an interrupt at a specific time of day
 * 3) Periodic Interrupt - generate periodic interrupt, with frequencies
 *    2Hz-8192Hz (2Hz-64Hz for non-root user) (all freqs in powers of 2)
 * (1) and (2) above are implemented using polling at a frequency of
 * 64 Hz. The exact frequency is a tradeoff between accuracy and interrupt
 * overhead. (DEFAULT_RTC_INT_FREQ)
 * For (3), we use interrupts at 64Hz or user specified periodic
 * frequency, whichever is higher.
 */
#include <linux/mc146818rtc.h>
#include <linux/rtc.h>

#define DEFAULT_RTC_INT_FREQ	64
#define DEFAULT_RTC_SHIFT	6
#define RTC_NUM_INTS		1

static unsigned long hpet_rtc_flags;
static unsigned long hpet_prev_update_sec;
static struct rtc_time hpet_alarm_time;
static unsigned long hpet_pie_count;
static unsigned long hpet_t1_cmp;
static unsigned long hpet_default_delta;
static unsigned long hpet_pie_delta;
static unsigned long hpet_pie_limit;

/*
 * Timer 1 for RTC emulation. We use one shot mode, as periodic mode
 * is not supported by all HPET implementations for timer 1.
 *
 * hpet_rtc_timer_init() is called when the rtc is initialized.
 */
int hpet_rtc_timer_init(void)
{
	unsigned long cfg, cnt, delta, flags;

	if (!is_hpet_enabled())
		return 0;

	if (!hpet_default_delta) {
		uint64_t clc;

		clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
		clc >>= hpet_clockevent.shift + DEFAULT_RTC_SHIFT;
		hpet_default_delta = (unsigned long) clc;
	}

	if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit)
		delta = hpet_default_delta;
	else
		delta = hpet_pie_delta;

	local_irq_save(flags);

	cnt = delta + hpet_readl(HPET_COUNTER);
	hpet_writel(cnt, HPET_T1_CMP);
	hpet_t1_cmp = cnt;

	cfg = hpet_readl(HPET_T1_CFG);
	cfg &= ~HPET_TN_PERIODIC;
	cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
	hpet_writel(cfg, HPET_T1_CFG);

	local_irq_restore(flags);

	return 1;
}

/*
 * The functions below are called from rtc driver.
 * Return 0 if HPET is not being used.
 * Otherwise do the necessary changes and return 1.
 */
int hpet_mask_rtc_irq_bit(unsigned long bit_mask)
{
	if (!is_hpet_enabled())
		return 0;

	hpet_rtc_flags &= ~bit_mask;
	return 1;
}

int hpet_set_rtc_irq_bit(unsigned long bit_mask)
{
	unsigned long oldbits = hpet_rtc_flags;

	if (!is_hpet_enabled())
		return 0;

	hpet_rtc_flags |= bit_mask;

	if (!oldbits)
		hpet_rtc_timer_init();

	return 1;
}

int hpet_set_alarm_time(unsigned char hrs, unsigned char min,
			unsigned char sec)
{
	if (!is_hpet_enabled())
		return 0;

	hpet_alarm_time.tm_hour = hrs;
	hpet_alarm_time.tm_min = min;
	hpet_alarm_time.tm_sec = sec;

	return 1;
}

int hpet_set_periodic_freq(unsigned long freq)
{
	uint64_t clc;

	if (!is_hpet_enabled())
		return 0;

	if (freq <= DEFAULT_RTC_INT_FREQ)
		hpet_pie_limit = DEFAULT_RTC_INT_FREQ / freq;
	else {
		clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
		do_div(clc, freq);
		clc >>= hpet_clockevent.shift;
		hpet_pie_delta = (unsigned long) clc;
	}
	return 1;
}

int hpet_rtc_dropped_irq(void)
{
	return is_hpet_enabled();
}

static void hpet_rtc_timer_reinit(void)
{
	unsigned long cfg, delta;
	int lost_ints = -1;

	if (unlikely(!hpet_rtc_flags)) {
		cfg = hpet_readl(HPET_T1_CFG);
		cfg &= ~HPET_TN_ENABLE;
		hpet_writel(cfg, HPET_T1_CFG);
		return;
	}

	if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit)
		delta = hpet_default_delta;
	else
		delta = hpet_pie_delta;

	/*
	 * Increment the comparator value until we are ahead of the
	 * current count.
	 */
	do {
		hpet_t1_cmp += delta;
		hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
		lost_ints++;
	} while ((long)(hpet_readl(HPET_COUNTER) - hpet_t1_cmp) > 0);

	if (lost_ints) {
		if (hpet_rtc_flags & RTC_PIE)
			hpet_pie_count += lost_ints;
		if (printk_ratelimit())
			printk(KERN_WARNING "rtc: lost %d interrupts\n",
				lost_ints);
	}
}

irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
{
	struct rtc_time curr_time;
	unsigned long rtc_int_flag = 0;

	hpet_rtc_timer_reinit();

	if (hpet_rtc_flags & (RTC_UIE | RTC_AIE))
		rtc_get_rtc_time(&curr_time);

	if (hpet_rtc_flags & RTC_UIE &&
	    curr_time.tm_sec != hpet_prev_update_sec) {
		rtc_int_flag = RTC_UF;
		hpet_prev_update_sec = curr_time.tm_sec;
	}

	if (hpet_rtc_flags & RTC_PIE &&
	    ++hpet_pie_count >= hpet_pie_limit) {
		rtc_int_flag |= RTC_PF;
		hpet_pie_count = 0;
	}

	if (hpet_rtc_flags & RTC_PIE &&
	    (curr_time.tm_sec == hpet_alarm_time.tm_sec) &&
	    (curr_time.tm_min == hpet_alarm_time.tm_min) &&
	    (curr_time.tm_hour == hpet_alarm_time.tm_hour))
			rtc_int_flag |= RTC_AF;

	if (rtc_int_flag) {
		rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));
		rtc_interrupt(rtc_int_flag, dev_id);
	}
	return IRQ_HANDLED;
}
#endif
Commit	Line	Data
5d0cf410	1	#include <linux/clocksource.h>
e9e2cdb4	2	#include <linux/clockchips.h>
28769149	3	#include <linux/delay.h>
5d0cf410	4	#include <linux/errno.h>
	5	#include <linux/hpet.h>
	6	#include <linux/init.h>
399afa4f ML	7	#include <linux/sysdev.h>
399afa4f ML	8	#include <linux/pm.h>
0655d7c3	9	#include <linux/delay.h>
5d0cf410	10
28769149	11	#include <asm/fixmap.h>
5d0cf410	12	#include <asm/hpet.h>
06a24dec	13	#include <asm/i8253.h>
5d0cf410	14	#include <asm/io.h>
5d0cf410	15
7f9f303a	16	#define HPET_MASK CLOCKSOURCE_MASK(32)
5d0cf410	17	#define HPET_SHIFT 22
	18
	19	/* FSEC = 10^-15 NSEC = 10^-9 */
	20	#define FSEC_PER_NSEC 1000000
	21
e9e2cdb4 TG	22	/*
	23	* HPET address is set in acpi/boot.c, when an ACPI entry exists
	24	*/
	25	unsigned long hpet_address;
06a24dec	26	static void __iomem *hpet_virt_address;
e9e2cdb4	27
31c435d7	28	unsigned long hpet_readl(unsigned long a)
e9e2cdb4 TG	29	{
	30	return readl(hpet_virt_address + a);
	31	}
	32
	33	static inline void hpet_writel(unsigned long d, unsigned long a)
	34	{
	35	writel(d, hpet_virt_address + a);
	36	}
	37
28769149 TG	38	#ifdef CONFIG_X86_64
	39
	40	#include <asm/pgtable.h>
	41
	42	static inline void hpet_set_mapping(void)
	43	{
	44	set_fixmap_nocache(FIX_HPET_BASE, hpet_address);
	45	__set_fixmap(VSYSCALL_HPET, hpet_address, PAGE_KERNEL_VSYSCALL_NOCACHE);
	46	hpet_virt_address = (void __iomem *)fix_to_virt(FIX_HPET_BASE);
	47	}
	48
	49	static inline void hpet_clear_mapping(void)
	50	{
	51	hpet_virt_address = NULL;
	52	}
	53
	54	#else
	55
06a24dec TG	56	static inline void hpet_set_mapping(void)
	57	{
	58	hpet_virt_address = ioremap_nocache(hpet_address, HPET_MMAP_SIZE);
	59	}
	60
	61	static inline void hpet_clear_mapping(void)
	62	{
	63	iounmap(hpet_virt_address);
	64	hpet_virt_address = NULL;
	65	}
28769149	66	#endif
06a24dec	67
e9e2cdb4 TG	68	/*
	69	* HPET command line enable / disable
	70	*/
	71	static int boot_hpet_disable;
	72
	73	static int __init hpet_setup(char* str)
	74	{
	75	if (str) {
	76	if (!strncmp("disable", str, 7))
	77	boot_hpet_disable = 1;
	78	}
	79	return 1;
	80	}
	81	__setup("hpet=", hpet_setup);
	82
28769149 TG	83	static int __init disable_hpet(char *str)
	84	{
	85	boot_hpet_disable = 1;
	86	return 1;
	87	}
	88	__setup("nohpet", disable_hpet);
	89
e9e2cdb4 TG	90	static inline int is_hpet_capable(void)
	91	{
	92	return (!boot_hpet_disable && hpet_address);
	93	}
	94
	95	/*
	96	* HPET timer interrupt enable / disable
	97	*/
	98	static int hpet_legacy_int_enabled;
	99
	100	/**
	101	* is_hpet_enabled - check whether the hpet timer interrupt is enabled
	102	*/
	103	int is_hpet_enabled(void)
	104	{
	105	return is_hpet_capable() && hpet_legacy_int_enabled;
	106	}
	107
	108	/*
	109	* When the hpet driver (/dev/hpet) is enabled, we need to reserve
	110	* timer 0 and timer 1 in case of RTC emulation.
	111	*/
	112	#ifdef CONFIG_HPET
	113	static void hpet_reserve_platform_timers(unsigned long id)
	114	{
	115	struct hpet __iomem *hpet = hpet_virt_address;
	116	struct hpet_timer __iomem *timer = &hpet->hpet_timers[2];
	117	unsigned int nrtimers, i;
	118	struct hpet_data hd;
	119
	120	nrtimers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;
	121
	122	memset(&hd, 0, sizeof (hd));
	123	hd.hd_phys_address = hpet_address;
06a24dec	124	hd.hd_address = hpet;
e9e2cdb4 TG	125	hd.hd_nirqs = nrtimers;
	126	hd.hd_flags = HPET_DATA_PLATFORM;
	127	hpet_reserve_timer(&hd, 0);
	128
	129	#ifdef CONFIG_HPET_EMULATE_RTC
	130	hpet_reserve_timer(&hd, 1);
	131	#endif
	132
	133	hd.hd_irq[0] = HPET_LEGACY_8254;
	134	hd.hd_irq[1] = HPET_LEGACY_RTC;
	135
	136	for (i = 2; i < nrtimers; timer++, i++)
	137	hd.hd_irq[i] = (timer->hpet_config & Tn_INT_ROUTE_CNF_MASK) >>
	138	Tn_INT_ROUTE_CNF_SHIFT;
	139
	140	hpet_alloc(&hd);
	141
	142	}
	143	#else
	144	static void hpet_reserve_platform_timers(unsigned long id) { }
	145	#endif
	146
	147	/*
	148	* Common hpet info
	149	*/
	150	static unsigned long hpet_period;
	151
610bf2f1	152	static void hpet_legacy_set_mode(enum clock_event_mode mode,
e9e2cdb4	153	struct clock_event_device *evt);
610bf2f1	154	static int hpet_legacy_next_event(unsigned long delta,
e9e2cdb4 TG	155	struct clock_event_device *evt);
	156
	157	/*
	158	* The hpet clock event device
	159	*/
	160	static struct clock_event_device hpet_clockevent = {
	161	.name = "hpet",
	162	.features = CLOCK_EVT_FEAT_PERIODIC \| CLOCK_EVT_FEAT_ONESHOT,
610bf2f1 VP	163	.set_mode = hpet_legacy_set_mode,
610bf2f1 VP	164	.set_next_event = hpet_legacy_next_event,
e9e2cdb4 TG	165	.shift = 32,
	166	.irq = 0,
	167	};
	168
	169	static void hpet_start_counter(void)
	170	{
	171	unsigned long cfg = hpet_readl(HPET_CFG);
	172
	173	cfg &= ~HPET_CFG_ENABLE;
	174	hpet_writel(cfg, HPET_CFG);
	175	hpet_writel(0, HPET_COUNTER);
	176	hpet_writel(0, HPET_COUNTER + 4);
	177	cfg \|= HPET_CFG_ENABLE;
	178	hpet_writel(cfg, HPET_CFG);
	179	}
	180
610bf2f1	181	static void hpet_enable_legacy_int(void)
e9e2cdb4 TG	182	{
	183	unsigned long cfg = hpet_readl(HPET_CFG);
	184
	185	cfg \|= HPET_CFG_LEGACY;
	186	hpet_writel(cfg, HPET_CFG);
	187	hpet_legacy_int_enabled = 1;
	188	}
	189
610bf2f1 VP	190	static void hpet_legacy_clockevent_register(void)
	191	{
	192	uint64_t hpet_freq;
	193
	194	/* Start HPET legacy interrupts */
	195	hpet_enable_legacy_int();
	196
	197	/*
	198	* The period is a femto seconds value. We need to calculate the
	199	* scaled math multiplication factor for nanosecond to hpet tick
	200	* conversion.
	201	*/
	202	hpet_freq = 1000000000000000ULL;
	203	do_div(hpet_freq, hpet_period);
	204	hpet_clockevent.mult = div_sc((unsigned long) hpet_freq,
	205	NSEC_PER_SEC, 32);
	206	/* Calculate the min / max delta */
	207	hpet_clockevent.max_delta_ns = clockevent_delta2ns(0x7FFFFFFF,
	208	&hpet_clockevent);
	209	hpet_clockevent.min_delta_ns = clockevent_delta2ns(0x30,
	210	&hpet_clockevent);
	211
	212	/*
	213	* Start hpet with the boot cpu mask and make it
	214	* global after the IO_APIC has been initialized.
	215	*/
	216	hpet_clockevent.cpumask = cpumask_of_cpu(smp_processor_id());
	217	clockevents_register_device(&hpet_clockevent);
	218	global_clock_event = &hpet_clockevent;
	219	printk(KERN_DEBUG "hpet clockevent registered\n");
	220	}
	221
	222	static void hpet_legacy_set_mode(enum clock_event_mode mode,
e9e2cdb4 TG	223	struct clock_event_device *evt)
	224	{
	225	unsigned long cfg, cmp, now;
	226	uint64_t delta;
	227
	228	switch(mode) {
	229	case CLOCK_EVT_MODE_PERIODIC:
	230	delta = ((uint64_t)(NSEC_PER_SEC/HZ)) * hpet_clockevent.mult;
	231	delta >>= hpet_clockevent.shift;
	232	now = hpet_readl(HPET_COUNTER);
	233	cmp = now + (unsigned long) delta;
	234	cfg = hpet_readl(HPET_T0_CFG);
	235	cfg \|= HPET_TN_ENABLE \| HPET_TN_PERIODIC \|
	236	HPET_TN_SETVAL \| HPET_TN_32BIT;
	237	hpet_writel(cfg, HPET_T0_CFG);
	238	/*
	239	* The first write after writing TN_SETVAL to the
	240	* config register sets the counter value, the second
	241	* write sets the period.
	242	*/
	243	hpet_writel(cmp, HPET_T0_CMP);
	244	udelay(1);
	245	hpet_writel((unsigned long) delta, HPET_T0_CMP);
	246	break;
	247
	248	case CLOCK_EVT_MODE_ONESHOT:
	249	cfg = hpet_readl(HPET_T0_CFG);
	250	cfg &= ~HPET_TN_PERIODIC;
	251	cfg \|= HPET_TN_ENABLE \| HPET_TN_32BIT;
	252	hpet_writel(cfg, HPET_T0_CFG);
	253	break;
	254
	255	case CLOCK_EVT_MODE_UNUSED:
	256	case CLOCK_EVT_MODE_SHUTDOWN:
	257	cfg = hpet_readl(HPET_T0_CFG);
	258	cfg &= ~HPET_TN_ENABLE;
	259	hpet_writel(cfg, HPET_T0_CFG);
	260	break;
18de5bc4 TG	261
18de5bc4 TG	262	case CLOCK_EVT_MODE_RESUME:
610bf2f1	263	hpet_enable_legacy_int();
18de5bc4	264	break;
e9e2cdb4 TG	265	}
	266	}
	267
610bf2f1	268	static int hpet_legacy_next_event(unsigned long delta,
e9e2cdb4 TG	269	struct clock_event_device *evt)
	270	{
	271	unsigned long cnt;
	272
	273	cnt = hpet_readl(HPET_COUNTER);
	274	cnt += delta;
	275	hpet_writel(cnt, HPET_T0_CMP);
	276
c7f6d15f	277	return ((long)(hpet_readl(HPET_COUNTER) - cnt ) > 0) ? -ETIME : 0;
e9e2cdb4 TG	278	}
e9e2cdb4 TG	279
6bb74df4	280	/*
	281	* Clock source related code
	282	*/
	283	static cycle_t read_hpet(void)
	284	{
	285	return (cycle_t)hpet_readl(HPET_COUNTER);
	286	}
	287
28769149 TG	288	#ifdef CONFIG_X86_64
	289	static cycle_t __vsyscall_fn vread_hpet(void)
	290	{
	291	return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + 0xf0);
	292	}
	293	#endif
	294
6bb74df4	295	static struct clocksource clocksource_hpet = {
	296	.name = "hpet",
	297	.rating = 250,
	298	.read = read_hpet,
	299	.mask = HPET_MASK,
	300	.shift = HPET_SHIFT,
	301	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
18de5bc4	302	.resume = hpet_start_counter,
28769149 TG	303	#ifdef CONFIG_X86_64
	304	.vread = vread_hpet,
	305	#endif
6bb74df4	306	};
6bb74df4	307
610bf2f1	308	static int hpet_clocksource_register(void)
e9e2cdb4	309	{
075bcd1f TG	310	u64 tmp, start, now;
075bcd1f TG	311	cycle_t t1;
e9e2cdb4	312
e9e2cdb4 TG	313	/* Start the counter */
	314	hpet_start_counter();
	315
075bcd1f TG	316	/* Verify whether hpet counter works */
	317	t1 = read_hpet();
	318	rdtscll(start);
	319
	320	/*
	321	* We don't know the TSC frequency yet, but waiting for
	322	* 200000 TSC cycles is safe:
	323	* 4 GHz == 50us
	324	* 1 GHz == 200us
	325	*/
	326	do {
	327	rep_nop();
	328	rdtscll(now);
	329	} while ((now - start) < 200000UL);
	330
	331	if (t1 == read_hpet()) {
	332	printk(KERN_WARNING
	333	"HPET counter not counting. HPET disabled\n");
610bf2f1	334	return -ENODEV;
075bcd1f TG	335	}
075bcd1f TG	336
6bb74df4	337	/* Initialize and register HPET clocksource
	338	*
	339	* hpet period is in femto seconds per cycle
	340	* so we need to convert this to ns/cyc units
	341	* aproximated by mult/2^shift
	342	*
	343	* fsec/cyc * 1nsec/1000000fsec = nsec/cyc = mult/2^shift
	344	* fsec/cyc * 1ns/1000000fsec * 2^shift = mult
	345	* fsec/cyc * 2^shift * 1nsec/1000000fsec = mult
	346	* (fsec/cyc << shift)/1000000 = mult
	347	* (hpet_period << shift)/FSEC_PER_NSEC = mult
	348	*/
	349	tmp = (u64)hpet_period << HPET_SHIFT;
	350	do_div(tmp, FSEC_PER_NSEC);
	351	clocksource_hpet.mult = (u32)tmp;
	352
	353	clocksource_register(&clocksource_hpet);
	354
610bf2f1 VP	355	return 0;
	356	}
	357
	358	/*
	359	* Try to setup the HPET timer
	360	*/
	361	int __init hpet_enable(void)
	362	{
	363	unsigned long id;
	364
	365	if (!is_hpet_capable())
	366	return 0;
	367
	368	hpet_set_mapping();
	369
	370	/*
	371	* Read the period and check for a sane value:
	372	*/
	373	hpet_period = hpet_readl(HPET_PERIOD);
	374	if (hpet_period < HPET_MIN_PERIOD \|\| hpet_period > HPET_MAX_PERIOD)
	375	goto out_nohpet;
	376
	377	/*
	378	* Read the HPET ID register to retrieve the IRQ routing
	379	* information and the number of channels
	380	*/
	381	id = hpet_readl(HPET_ID);
	382
	383	#ifdef CONFIG_HPET_EMULATE_RTC
	384	/*
	385	* The legacy routing mode needs at least two channels, tick timer
	386	* and the rtc emulation channel.
	387	*/
	388	if (!(id & HPET_ID_NUMBER))
	389	goto out_nohpet;
	390	#endif
	391
	392	if (hpet_clocksource_register())
	393	goto out_nohpet;
	394
e9e2cdb4	395	if (id & HPET_ID_LEGSUP) {
610bf2f1	396	hpet_legacy_clockevent_register();
e9e2cdb4 TG	397	return 1;
	398	}
	399	return 0;
5d0cf410	400
e9e2cdb4	401	out_nohpet:
06a24dec	402	hpet_clear_mapping();
399afa4f	403	boot_hpet_disable = 1;
e9e2cdb4 TG	404	return 0;
	405	}
	406
28769149 TG	407	/*
	408	* Needs to be late, as the reserve_timer code calls kalloc !
	409	*
	410	* Not a problem on i386 as hpet_enable is called from late_time_init,
	411	* but on x86_64 it is necessary !
	412	*/
	413	static __init int hpet_late_init(void)
	414	{
	415	if (!is_hpet_capable())
	416	return -ENODEV;
	417
	418	hpet_reserve_platform_timers(hpet_readl(HPET_ID));
	419	return 0;
	420	}
	421	fs_initcall(hpet_late_init);
	422
e9e2cdb4 TG	423	#ifdef CONFIG_HPET_EMULATE_RTC
	424
	425	/* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET
	426	* is enabled, we support RTC interrupt functionality in software.
	427	* RTC has 3 kinds of interrupts:
	428	* 1) Update Interrupt - generate an interrupt, every sec, when RTC clock
	429	* is updated
	430	* 2) Alarm Interrupt - generate an interrupt at a specific time of day
	431	* 3) Periodic Interrupt - generate periodic interrupt, with frequencies
	432	* 2Hz-8192Hz (2Hz-64Hz for non-root user) (all freqs in powers of 2)
	433	* (1) and (2) above are implemented using polling at a frequency of
	434	* 64 Hz. The exact frequency is a tradeoff between accuracy and interrupt
	435	* overhead. (DEFAULT_RTC_INT_FREQ)
	436	* For (3), we use interrupts at 64Hz or user specified periodic
	437	* frequency, whichever is higher.
	438	*/
	439	#include <linux/mc146818rtc.h>
	440	#include <linux/rtc.h>
	441
	442	#define DEFAULT_RTC_INT_FREQ 64
	443	#define DEFAULT_RTC_SHIFT 6
	444	#define RTC_NUM_INTS 1
	445
	446	static unsigned long hpet_rtc_flags;
	447	static unsigned long hpet_prev_update_sec;
	448	static struct rtc_time hpet_alarm_time;
	449	static unsigned long hpet_pie_count;
	450	static unsigned long hpet_t1_cmp;
	451	static unsigned long hpet_default_delta;
	452	static unsigned long hpet_pie_delta;
	453	static unsigned long hpet_pie_limit;
	454
	455	/*
	456	* Timer 1 for RTC emulation. We use one shot mode, as periodic mode
	457	* is not supported by all HPET implementations for timer 1.
	458	*
	459	* hpet_rtc_timer_init() is called when the rtc is initialized.
	460	*/
	461	int hpet_rtc_timer_init(void)
	462	{
	463	unsigned long cfg, cnt, delta, flags;
	464
	465	if (!is_hpet_enabled())
	466	return 0;
	467
	468	if (!hpet_default_delta) {
	469	uint64_t clc;
	470
	471	clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
	472	clc >>= hpet_clockevent.shift + DEFAULT_RTC_SHIFT;
	473	hpet_default_delta = (unsigned long) clc;
	474	}
	475
	476	if (!(hpet_rtc_flags & RTC_PIE) \|\| hpet_pie_limit)
	477	delta = hpet_default_delta;
	478	else
	479	delta = hpet_pie_delta;
	480
	481	local_irq_save(flags);
	482
	483	cnt = delta + hpet_readl(HPET_COUNTER);
	484	hpet_writel(cnt, HPET_T1_CMP);
	485	hpet_t1_cmp = cnt;
	486
487	cfg = hpet_readl(HPET_T1_CFG);
488	cfg &= ~HPET_TN_PERIODIC;
489	cfg \|= HPET_TN_ENABLE \| HPET_TN_32BIT;
490	hpet_writel(cfg, HPET_T1_CFG);
491
492	local_irq_restore(flags);
493
494	return 1;
495	}
496
497	/*
498	* The functions below are called from rtc driver.
499	* Return 0 if HPET is not being used.
500	* Otherwise do the necessary changes and return 1.
501	*/
502	int hpet_mask_rtc_irq_bit(unsigned long bit_mask)
503	{
504	if (!is_hpet_enabled())
505	return 0;
506
507	hpet_rtc_flags &= ~bit_mask;
508	return 1;
509	}
510
511	int hpet_set_rtc_irq_bit(unsigned long bit_mask)
512	{
513	unsigned long oldbits = hpet_rtc_flags;
514
515	if (!is_hpet_enabled())
516	return 0;
517
518	hpet_rtc_flags \|= bit_mask;
519
520	if (!oldbits)
521	hpet_rtc_timer_init();
522
523	return 1;
524	}
525
526	int hpet_set_alarm_time(unsigned char hrs, unsigned char min,
527	unsigned char sec)
528	{
529	if (!is_hpet_enabled())
530	return 0;
531
532	hpet_alarm_time.tm_hour = hrs;
533	hpet_alarm_time.tm_min = min;
534	hpet_alarm_time.tm_sec = sec;
535
536	return 1;
537	}
538
539	int hpet_set_periodic_freq(unsigned long freq)
540	{
541	uint64_t clc;
542
543	if (!is_hpet_enabled())
544	return 0;
545
546	if (freq <= DEFAULT_RTC_INT_FREQ)
547	hpet_pie_limit = DEFAULT_RTC_INT_FREQ / freq;
548	else {
549	clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
550	do_div(clc, freq);
551	clc >>= hpet_clockevent.shift;
552	hpet_pie_delta = (unsigned long) clc;
553	}
554	return 1;
555	}
556
557	int hpet_rtc_dropped_irq(void)
558	{
559	return is_hpet_enabled();
560	}
561
562	static void hpet_rtc_timer_reinit(void)
563	{
564	unsigned long cfg, delta;
565	int lost_ints = -1;
566
567	if (unlikely(!hpet_rtc_flags)) {
568	cfg = hpet_readl(HPET_T1_CFG);
569	cfg &= ~HPET_TN_ENABLE;
570	hpet_writel(cfg, HPET_T1_CFG);
571	return;
572	}
573
574	if (!(hpet_rtc_flags & RTC_PIE) \|\| hpet_pie_limit)
575	delta = hpet_default_delta;
576	else
577	delta = hpet_pie_delta;
578
579	/*
580	* Increment the comparator value until we are ahead of the
581	* current count.
582	*/
583	do {
584	hpet_t1_cmp += delta;
585	hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
586	lost_ints++;
587	} while ((long)(hpet_readl(HPET_COUNTER) - hpet_t1_cmp) > 0);
588
589	if (lost_ints) {
590	if (hpet_rtc_flags & RTC_PIE)
591	hpet_pie_count += lost_ints;
592	if (printk_ratelimit())
593	printk(KERN_WARNING "rtc: lost %d interrupts\n",
594	lost_ints);
595	}
596	}
597
598	irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
599	{
600	struct rtc_time curr_time;
601	unsigned long rtc_int_flag = 0;
602
603	hpet_rtc_timer_reinit();
604
605	if (hpet_rtc_flags & (RTC_UIE \| RTC_AIE))
606	rtc_get_rtc_time(&curr_time);
607
608	if (hpet_rtc_flags & RTC_UIE &&
609	curr_time.tm_sec != hpet_prev_update_sec) {
610	rtc_int_flag = RTC_UF;
611	hpet_prev_update_sec = curr_time.tm_sec;
612	}
613
614	if (hpet_rtc_flags & RTC_PIE &&
615	++hpet_pie_count >= hpet_pie_limit) {
616	rtc_int_flag \|= RTC_PF;
617	hpet_pie_count = 0;
618	}
619
620	if (hpet_rtc_flags & RTC_PIE &&
621	(curr_time.tm_sec == hpet_alarm_time.tm_sec) &&
622	(curr_time.tm_min == hpet_alarm_time.tm_min) &&
623	(curr_time.tm_hour == hpet_alarm_time.tm_hour))
624	rtc_int_flag \|= RTC_AF;
625
626	if (rtc_int_flag) {
627	rtc_int_flag \|= (RTC_IRQF \| (RTC_NUM_INTS << 8));
628	rtc_interrupt(rtc_int_flag, dev_id);
629	}
630	return IRQ_HANDLED;
631	}
632	#endif