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Commit 69365272 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

Merge branch 'fortglx/4.6/time' of https://git.linaro.org/people/john.stultz/linux into timers/core 

Pull the cross-timestamp infrastructure from John Stultz.

Allows precise correlation of device timestamps with system time. Primary use
cases being PTP and audio.
parents 82e88ff1 01d7ada5

Documentation/ptp/testptp.c

+4 −2
Original line number Diff line number Diff line
@@ -277,13 +277,15 @@ int main(int argc, char *argv[]) 
			       "  %d external time stamp channels\n"

			       "  %d programmable periodic signals\n"

			       "  %d pulse per second\n"

			       "  %d programmable pins\n",

			       "  %d programmable pins\n"

			       "  %d cross timestamping\n",

			       caps.max_adj,

			       caps.n_alarm,

			       caps.n_ext_ts,

			       caps.n_per_out,

			       caps.pps,

			       caps.n_pins);

			       caps.n_pins,

			       caps.cross_timestamping);

		}

	}

arch/x86/include/asm/cpufeature.h

+1 −1
Original line number Diff line number Diff line
@@ -85,7 +85,7 @@ 
#define X86_FEATURE_P4		( 3*32+ 7) /* "" P4 */

#define X86_FEATURE_CONSTANT_TSC ( 3*32+ 8) /* TSC ticks at a constant rate */

#define X86_FEATURE_UP		( 3*32+ 9) /* smp kernel running on up */

/* free, was #define X86_FEATURE_FXSAVE_LEAK ( 3*32+10) * "" FXSAVE leaks FOP/FIP/FOP */

#define X86_FEATURE_ART		(3*32+10) /* Platform has always running timer (ART) */

#define X86_FEATURE_ARCH_PERFMON ( 3*32+11) /* Intel Architectural PerfMon */

#define X86_FEATURE_PEBS	( 3*32+12) /* Precise-Event Based Sampling */

#define X86_FEATURE_BTS		( 3*32+13) /* Branch Trace Store */

arch/x86/include/asm/tsc.h

+2 −0
Original line number Diff line number Diff line
@@ -29,6 +29,8 @@ static inline cycles_t get_cycles(void) 
	return rdtsc();

}



extern struct system_counterval_t convert_art_to_tsc(cycle_t art);



extern void tsc_init(void);

extern void mark_tsc_unstable(char *reason);

extern int unsynchronized_tsc(void);

arch/x86/kernel/tsc.c

+59 −0
Original line number Diff line number Diff line
@@ -43,6 +43,11 @@ static DEFINE_STATIC_KEY_FALSE(__use_tsc); 


int tsc_clocksource_reliable;



static u32 art_to_tsc_numerator;

static u32 art_to_tsc_denominator;

static u64 art_to_tsc_offset;

struct clocksource *art_related_clocksource;



/*

 * Use a ring-buffer like data structure, where a writer advances the head by

 * writing a new data entry and a reader advances the tail when it observes a
@@ -964,6 +969,37 @@ core_initcall(cpufreq_tsc); 


#endif /* CONFIG_CPU_FREQ */



#define ART_CPUID_LEAF (0x15)

#define ART_MIN_DENOMINATOR (1)





/*

 * If ART is present detect the numerator:denominator to convert to TSC

 */

static void detect_art(void)

{

	unsigned int unused[2];



	if (boot_cpu_data.cpuid_level < ART_CPUID_LEAF)

		return;



	cpuid(ART_CPUID_LEAF, &art_to_tsc_denominator,

	      &art_to_tsc_numerator, unused, unused+1);



	/* Don't enable ART in a VM, non-stop TSC required */

	if (boot_cpu_has(X86_FEATURE_HYPERVISOR) ||

	    !boot_cpu_has(X86_FEATURE_NONSTOP_TSC) ||

	    art_to_tsc_denominator < ART_MIN_DENOMINATOR)

		return;



	if (rdmsrl_safe(MSR_IA32_TSC_ADJUST, &art_to_tsc_offset))

		return;



	/* Make this sticky over multiple CPU init calls */

	setup_force_cpu_cap(X86_FEATURE_ART);

}





/* clocksource code */



static struct clocksource clocksource_tsc;
@@ -1071,6 +1107,25 @@ int unsynchronized_tsc(void) 
	return 0;

}



/*

 * Convert ART to TSC given numerator/denominator found in detect_art()

 */

struct system_counterval_t convert_art_to_tsc(cycle_t art)

{

	u64 tmp, res, rem;



	rem = do_div(art, art_to_tsc_denominator);



	res = art * art_to_tsc_numerator;

	tmp = rem * art_to_tsc_numerator;



	do_div(tmp, art_to_tsc_denominator);

	res += tmp + art_to_tsc_offset;



	return (struct system_counterval_t) {.cs = art_related_clocksource,

			.cycles = res};

}

EXPORT_SYMBOL(convert_art_to_tsc);



static void tsc_refine_calibration_work(struct work_struct *work);

static DECLARE_DELAYED_WORK(tsc_irqwork, tsc_refine_calibration_work);
@@ -1142,6 +1197,8 @@ static void tsc_refine_calibration_work(struct work_struct *work) 
		(unsigned long)tsc_khz % 1000);



out:

	if (boot_cpu_has(X86_FEATURE_ART))

		art_related_clocksource = &clocksource_tsc;

	clocksource_register_khz(&clocksource_tsc, tsc_khz);

}
@@ -1235,6 +1292,8 @@ void __init tsc_init(void) 
		mark_tsc_unstable("TSCs unsynchronized");



	check_system_tsc_reliable();



	detect_art();

}



#ifdef CONFIG_SMP

drivers/net/ethernet/intel/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -83,6 +83,15 @@ config E1000E 
	  To compile this driver as a module, choose M here. The module

	  will be called e1000e.



config E1000E_HWTS

	bool "Support HW cross-timestamp on PCH devices"

	default y

	depends on E1000E && X86

	---help---

	 Say Y to enable hardware supported cross-timestamping on PCH

	 devices. The cross-timestamp is available through the PTP clock

	 driver precise cross-timestamp ioctl (PTP_SYS_OFFSET_PRECISE).



config IGB

	tristate "Intel(R) 82575/82576 PCI-Express Gigabit Ethernet support"

	depends on PCI