x86/apic: Allow use of lapic timer early calibration result (1ade93ef) · Commits · 戴 / test

arch/x86/include/asm/apic.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -49,6 +49,7 @@ extern unsigned int apic_verbosity;
		extern int local_apic_timer_c2_ok;

		extern int disable_apic;
		extern unsigned int lapic_timer_frequency;

		#ifdef CONFIG_SMP
		extern void __inquire_remote_apic(int apicid);

arch/x86/kernel/apic/apic.c

+26 −7

Original line number	Diff line number	Diff line
		@@ -186,7 +186,7 @@ static struct resource lapic_resource = {
		.flags = IORESOURCE_MEM \| IORESOURCE_BUSY,
		};

		static unsigned int calibration_result;
		unsigned int lapic_timer_frequency = 0;

		static void apic_pm_activate(void);

		@@ -454,7 +454,7 @@ static void lapic_timer_setup(enum clock_event_mode mode,
		switch (mode) {
		case CLOCK_EVT_MODE_PERIODIC:
		case CLOCK_EVT_MODE_ONESHOT:
		__setup_APIC_LVTT(calibration_result,
		__setup_APIC_LVTT(lapic_timer_frequency,
		mode != CLOCK_EVT_MODE_PERIODIC, 1);
		break;
		case CLOCK_EVT_MODE_UNUSED:
		@@ -638,6 +638,25 @@ static int __init calibrate_APIC_clock(void)
		long delta, deltatsc;
		int pm_referenced = 0;

		/**
		* check if lapic timer has already been calibrated by platform
		* specific routine, such as tsc calibration code. if so, we just fill
		* in the clockevent structure and return.
		*/

		if (lapic_timer_frequency) {
		apic_printk(APIC_VERBOSE, "lapic timer already calibrated %d\n",
		lapic_timer_frequency);
		lapic_clockevent.mult = div_sc(lapic_timer_frequency/APIC_DIVISOR,
		TICK_NSEC, lapic_clockevent.shift);
		lapic_clockevent.max_delta_ns =
		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
		lapic_clockevent.min_delta_ns =
		clockevent_delta2ns(0xF, &lapic_clockevent);
		lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
		return 0;
		}

		local_irq_disable();

		/* Replace the global interrupt handler */
		@@ -679,12 +698,12 @@ static int __init calibrate_APIC_clock(void)
		lapic_clockevent.min_delta_ns =
		clockevent_delta2ns(0xF, &lapic_clockevent);

		calibration_result = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
		lapic_timer_frequency = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;

		apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
		apic_printk(APIC_VERBOSE, "..... mult: %u\n", lapic_clockevent.mult);
		apic_printk(APIC_VERBOSE, "..... calibration result: %u\n",
		calibration_result);
		lapic_timer_frequency);

		if (cpu_has_tsc) {
		apic_printk(APIC_VERBOSE, "..... CPU clock speed is "
		@@ -695,13 +714,13 @@ static int __init calibrate_APIC_clock(void)

		apic_printk(APIC_VERBOSE, "..... host bus clock speed is "
		"%u.%04u MHz.\n",
		calibration_result / (1000000 / HZ),
		calibration_result % (1000000 / HZ));
		lapic_timer_frequency / (1000000 / HZ),
		lapic_timer_frequency % (1000000 / HZ));

		/*
		* Do a sanity check on the APIC calibration result
		*/
		if (calibration_result < (1000000 / HZ)) {
		if (lapic_timer_frequency < (1000000 / HZ)) {
		local_irq_enable();
		pr_warning("APIC frequency too slow, disabling apic timer\n");
		return -1;

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