Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer updates from Thomas Gleixner:
 "The timer department delivers this time:

   - Support for cross clock domain timestamps in the core code plus a
     first user.  That allows more precise timestamping for PTP and
     later for audio and other peripherals.

     The ptp/e1000e patches have been acked by the relevant maintainers
     and are carried in the timer tree to avoid merge ordering issues.

   - Support for unregistering the current clocksource watchdog.  That
     lifts a limitation for switching clocksources which has been there
     from day 1

   - The usual pile of fixes and updates to the core and the drivers.
     Nothing outstanding and exciting"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits)
  time/timekeeping: Work around false positive GCC warning
  e1000e: Adds hardware supported cross timestamp on e1000e nic
  ptp: Add PTP_SYS_OFFSET_PRECISE for driver crosstimestamping
  x86/tsc: Always Running Timer (ART) correlated clocksource
  hrtimer: Revert CLOCK_MONOTONIC_RAW support
  time: Add history to cross timestamp interface supporting slower devices
  time: Add driver cross timestamp interface for higher precision time synchronization
  time: Remove duplicated code in ktime_get_raw_and_real()
  time: Add timekeeping snapshot code capturing system time and counter
  time: Add cycles to nanoseconds translation
  jiffies: Use CLOCKSOURCE_MASK instead of constant
  clocksource: Introduce clocksource_freq2mult()
  clockevents/drivers/exynos_mct: Implement ->set_state_oneshot_stopped()
  clockevents/drivers/arm_global_timer: Implement ->set_state_oneshot_stopped()
  clockevents/drivers/arm_arch_timer: Implement ->set_state_oneshot_stopped()
  clocksource/drivers/arm_global_timer: Register delay timer
  clocksource/drivers/lpc32xx: Support timer-based ARM delay
  clocksource/drivers/lpc32xx: Support periodic mode
  clocksource/drivers/lpc32xx: Don't use the prescaler counter for clockevents
  clocksource/drivers/rockchip: Add err handle for rk_timer_init
  ...

25 files changed, 728 insertions, 106 deletions

diff --git a/Documentation/ptp/testptp.c b/Documentation/ptp/testptp.c
index 6c6247aaa7b9..d99012f41602 100644
--- a/Documentation/ptp/testptp.c
+++ b/Documentation/ptp/testptp.c
@@ -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);
                 }
         }
 
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 9e0567f4c081..074b7604bd51 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -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 */
diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index 6d7c5479bcea..174c4212780a 100644
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -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);
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 5a6cb4684e0f..56380440d862 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -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
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 33db7406c0e2..c346be650892 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -160,6 +160,7 @@ config CLKSRC_EFM32
 config CLKSRC_LPC32XX
         bool "Clocksource for LPC32XX" if COMPILE_TEST
         depends on GENERIC_CLOCKEVENTS && HAS_IOMEM
+        depends on ARM
         select CLKSRC_MMIO
         select CLKSRC_OF
         help
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index c64d543d64bf..f0dd9d42bc7b 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -32,6 +32,14 @@
 #define CNTTIDR         0x08
 #define CNTTIDR_VIRT(n) (BIT(1) << ((n) * 4))
 
+#define CNTACR(n)       (0x40 + ((n) * 4))
+#define CNTACR_RPCT     BIT(0)
+#define CNTACR_RVCT     BIT(1)
+#define CNTACR_RFRQ     BIT(2)
+#define CNTACR_RVOFF    BIT(3)
+#define CNTACR_RWVT     BIT(4)
+#define CNTACR_RWPT     BIT(5)
+
 #define CNTVCT_LO       0x08
 #define CNTVCT_HI       0x0c
 #define CNTFRQ          0x10
@@ -266,10 +274,12 @@ static void __arch_timer_setup(unsigned type,
                 if (arch_timer_use_virtual) {
                         clk->irq = arch_timer_ppi[VIRT_PPI];
                         clk->set_state_shutdown = arch_timer_shutdown_virt;
+                        clk->set_state_oneshot_stopped = arch_timer_shutdown_virt;
                         clk->set_next_event = arch_timer_set_next_event_virt;
                 } else {
                         clk->irq = arch_timer_ppi[PHYS_SECURE_PPI];
                         clk->set_state_shutdown = arch_timer_shutdown_phys;
+                        clk->set_state_oneshot_stopped = arch_timer_shutdown_phys;
                         clk->set_next_event = arch_timer_set_next_event_phys;
                 }
         } else {
@@ -279,10 +289,12 @@ static void __arch_timer_setup(unsigned type,
                 clk->cpumask = cpu_all_mask;
                 if (arch_timer_mem_use_virtual) {
                         clk->set_state_shutdown = arch_timer_shutdown_virt_mem;
+                        clk->set_state_oneshot_stopped = arch_timer_shutdown_virt_mem;
                         clk->set_next_event =
                                 arch_timer_set_next_event_virt_mem;
                 } else {
                         clk->set_state_shutdown = arch_timer_shutdown_phys_mem;
+                        clk->set_state_oneshot_stopped = arch_timer_shutdown_phys_mem;
                         clk->set_next_event =
                                 arch_timer_set_next_event_phys_mem;
                 }
@@ -757,7 +769,6 @@ static void __init arch_timer_mem_init(struct device_node *np)
         }
 
         cnttidr = readl_relaxed(cntctlbase + CNTTIDR);
-        iounmap(cntctlbase);
 
         /*
          * Try to find a virtual capable frame. Otherwise fall back to a
@@ -765,20 +776,31 @@ static void __init arch_timer_mem_init(struct device_node *np)
          */
         for_each_available_child_of_node(np, frame) {
                 int n;
+                u32 cntacr;
 
                 if (of_property_read_u32(frame, "frame-number", &n)) {
                         pr_err("arch_timer: Missing frame-number\n");
-                        of_node_put(best_frame);
                         of_node_put(frame);
-                        return;
+                        goto out;
                 }
 
-                if (cnttidr & CNTTIDR_VIRT(n)) {
+                /* Try enabling everything, and see what sticks */
+                cntacr = CNTACR_RFRQ | CNTACR_RWPT | CNTACR_RPCT |
+                         CNTACR_RWVT | CNTACR_RVOFF | CNTACR_RVCT;
+                writel_relaxed(cntacr, cntctlbase + CNTACR(n));
+                cntacr = readl_relaxed(cntctlbase + CNTACR(n));
+
+                if ((cnttidr & CNTTIDR_VIRT(n)) &&
+                    !(~cntacr & (CNTACR_RWVT | CNTACR_RVCT))) {
                         of_node_put(best_frame);
                         best_frame = frame;
                         arch_timer_mem_use_virtual = true;
                         break;
                 }
+
+                if (~cntacr & (CNTACR_RWPT | CNTACR_RPCT))
+                        continue;
+
                 of_node_put(best_frame);
                 best_frame = of_node_get(frame);
         }
@@ -786,24 +808,26 @@ static void __init arch_timer_mem_init(struct device_node *np)
         base = arch_counter_base = of_iomap(best_frame, 0);
         if (!base) {
                 pr_err("arch_timer: Can't map frame's registers\n");
-                of_node_put(best_frame);
-                return;
+                goto out;
         }
 
         if (arch_timer_mem_use_virtual)
                 irq = irq_of_parse_and_map(best_frame, 1);
         else
                 irq = irq_of_parse_and_map(best_frame, 0);
-        of_node_put(best_frame);
+
         if (!irq) {
                 pr_err("arch_timer: Frame missing %s irq",
                        arch_timer_mem_use_virtual ? "virt" : "phys");
-                return;
+                goto out;
         }
 
         arch_timer_detect_rate(base, np);
         arch_timer_mem_register(base, irq);
         arch_timer_common_init();
+out:
+        iounmap(cntctlbase);
+        of_node_put(best_frame);
 }
 CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
                        arch_timer_mem_init);
diff --git a/drivers/clocksource/arm_global_timer.c b/drivers/clocksource/arm_global_timer.c
index d189d8cb69f7..9df0d1699d22 100644
--- a/drivers/clocksource/arm_global_timer.c
+++ b/drivers/clocksource/arm_global_timer.c
@@ -16,6 +16,7 @@
 #include <linux/clockchips.h>
 #include <linux/cpu.h>
 #include <linux/clk.h>
+#include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/of.h>
@@ -174,6 +175,7 @@ static int gt_clockevents_init(struct clock_event_device *clk)
         clk->set_state_shutdown = gt_clockevent_shutdown;
         clk->set_state_periodic = gt_clockevent_set_periodic;
         clk->set_state_oneshot = gt_clockevent_shutdown;
+        clk->set_state_oneshot_stopped = gt_clockevent_shutdown;
         clk->set_next_event = gt_clockevent_set_next_event;
         clk->cpumask = cpumask_of(cpu);
         clk->rating = 300;
@@ -221,6 +223,21 @@ static u64 notrace gt_sched_clock_read(void)
 }
 #endif
 
+static unsigned long gt_read_long(void)
+{
+        return readl_relaxed(gt_base + GT_COUNTER0);
+}
+
+static struct delay_timer gt_delay_timer = {
+        .read_current_timer = gt_read_long,
+};
+
+static void __init gt_delay_timer_init(void)
+{
+        gt_delay_timer.freq = gt_clk_rate;
+        register_current_timer_delay(&gt_delay_timer);
+}
+
 static void __init gt_clocksource_init(void)
 {
         writel(0, gt_base + GT_CONTROL);
@@ -317,6 +334,7 @@ static void __init global_timer_of_register(struct device_node *np)
         /* Immediately configure the timer on the boot CPU */
         gt_clocksource_init();
         gt_clockevents_init(this_cpu_ptr(gt_evt));
+        gt_delay_timer_init();
 
         return;
 
diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index ff44082a0827..be09bc0b5e26 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -313,6 +313,7 @@ static struct clock_event_device mct_comp_device = {
         .set_state_periodic     = mct_set_state_periodic,
         .set_state_shutdown     = mct_set_state_shutdown,
         .set_state_oneshot      = mct_set_state_shutdown,
+        .set_state_oneshot_stopped = mct_set_state_shutdown,
         .tick_resume            = mct_set_state_shutdown,
 };
 
@@ -452,6 +453,7 @@ static int exynos4_local_timer_setup(struct mct_clock_event_device *mevt)
         evt->set_state_periodic = set_state_periodic;
         evt->set_state_shutdown = set_state_shutdown;
         evt->set_state_oneshot = set_state_shutdown;
+        evt->set_state_oneshot_stopped = set_state_shutdown;
         evt->tick_resume = set_state_shutdown;
         evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
         evt->rating = 450;
diff --git a/drivers/clocksource/rockchip_timer.c b/drivers/clocksource/rockchip_timer.c
index 8c77a529d0d4..b991b288c803 100644
--- a/drivers/clocksource/rockchip_timer.c
+++ b/drivers/clocksource/rockchip_timer.c
@@ -122,23 +122,23 @@ static void __init rk_timer_init(struct device_node *np)
         pclk = of_clk_get_by_name(np, "pclk");
         if (IS_ERR(pclk)) {
                 pr_err("Failed to get pclk for '%s'\n", TIMER_NAME);
-                return;
+                goto out_unmap;
         }
 
         if (clk_prepare_enable(pclk)) {
                 pr_err("Failed to enable pclk for '%s'\n", TIMER_NAME);
-                return;
+                goto out_unmap;
         }
 
         timer_clk = of_clk_get_by_name(np, "timer");
         if (IS_ERR(timer_clk)) {
                 pr_err("Failed to get timer clock for '%s'\n", TIMER_NAME);
-                return;
+                goto out_timer_clk;
         }
 
         if (clk_prepare_enable(timer_clk)) {
                 pr_err("Failed to enable timer clock\n");
-                return;
+                goto out_timer_clk;
         }
 
         bc_timer.freq = clk_get_rate(timer_clk);
@@ -146,7 +146,7 @@ static void __init rk_timer_init(struct device_node *np)
         irq = irq_of_parse_and_map(np, 0);
         if (!irq) {
                 pr_err("Failed to map interrupts for '%s'\n", TIMER_NAME);
-                return;
+                goto out_irq;
         }
 
         ce->name = TIMER_NAME;
@@ -164,10 +164,19 @@ static void __init rk_timer_init(struct device_node *np)
         ret = request_irq(irq, rk_timer_interrupt, IRQF_TIMER, TIMER_NAME, ce);
         if (ret) {
                 pr_err("Failed to initialize '%s': %d\n", TIMER_NAME, ret);
-                return;
+                goto out_irq;
         }
 
         clockevents_config_and_register(ce, bc_timer.freq, 1, UINT_MAX);
+
+        return;
+
+out_irq:
+        clk_disable_unprepare(timer_clk);
+out_timer_clk:
+        clk_disable_unprepare(pclk);
+out_unmap:
+        iounmap(bc_timer.base);
 }
 
 CLOCKSOURCE_OF_DECLARE(rk_timer, "rockchip,rk3288-timer", rk_timer_init);
diff --git a/drivers/clocksource/time-lpc32xx.c b/drivers/clocksource/time-lpc32xx.c
index 1316876b487a..daae61e8c820 100644
--- a/drivers/clocksource/time-lpc32xx.c
+++ b/drivers/clocksource/time-lpc32xx.c
@@ -18,6 +18,7 @@
 #include <linux/clk.h>
 #include <linux/clockchips.h>
 #include <linux/clocksource.h>
+#include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/kernel.h>
@@ -43,6 +44,7 @@
 struct lpc32xx_clock_event_ddata {
         struct clock_event_device evtdev;
         void __iomem *base;
+        u32 ticks_per_jiffy;
 };
 
 /* Needed for the sched clock */
@@ -53,6 +55,15 @@ static u64 notrace lpc32xx_read_sched_clock(void)
         return readl(clocksource_timer_counter);
 }
 
+static unsigned long lpc32xx_delay_timer_read(void)
+{
+        return readl(clocksource_timer_counter);
+}
+
+static struct delay_timer lpc32xx_delay_timer = {
+        .read_current_timer = lpc32xx_delay_timer_read,
+};
+
 static int lpc32xx_clkevt_next_event(unsigned long delta,
                                      struct clock_event_device *evtdev)
 {
@@ -60,14 +71,13 @@ static int lpc32xx_clkevt_next_event(unsigned long delta,
                 container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);
 
         /*
-         * Place timer in reset and program the delta in the prescale
-         * register (PR). When the prescale counter matches the value
-         * in PR the counter register is incremented and the compare
-         * match will trigger. After setup the timer is released from
-         * reset and enabled.
+         * Place timer in reset and program the delta in the match
+         * channel 0 (MR0). When the timer counter matches the value
+         * in MR0 register the match will trigger an interrupt.
+         * After setup the timer is released from reset and enabled.
          */
         writel_relaxed(LPC32XX_TIMER_TCR_CRST, ddata->base + LPC32XX_TIMER_TCR);
-        writel_relaxed(delta, ddata->base + LPC32XX_TIMER_PR);
+        writel_relaxed(delta, ddata->base + LPC32XX_TIMER_MR0);
         writel_relaxed(LPC32XX_TIMER_TCR_CEN, ddata->base + LPC32XX_TIMER_TCR);
 
         return 0;
@@ -86,11 +96,39 @@ static int lpc32xx_clkevt_shutdown(struct clock_event_device *evtdev)
 
 static int lpc32xx_clkevt_oneshot(struct clock_event_device *evtdev)
 {
+        struct lpc32xx_clock_event_ddata *ddata =
+                container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);
+
         /*
          * When using oneshot, we must also disable the timer
          * to wait for the first call to set_next_event().
          */
-        return lpc32xx_clkevt_shutdown(evtdev);
+        writel_relaxed(0, ddata->base + LPC32XX_TIMER_TCR);
+
+        /* Enable interrupt, reset on match and stop on match (MCR). */
+        writel_relaxed(LPC32XX_TIMER_MCR_MR0I | LPC32XX_TIMER_MCR_MR0R |
+                       LPC32XX_TIMER_MCR_MR0S, ddata->base + LPC32XX_TIMER_MCR);
+        return 0;
+}
+
+static int lpc32xx_clkevt_periodic(struct clock_event_device *evtdev)
+{
+        struct lpc32xx_clock_event_ddata *ddata =
+                container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);
+
+        /* Enable interrupt and reset on match. */
+        writel_relaxed(LPC32XX_TIMER_MCR_MR0I | LPC32XX_TIMER_MCR_MR0R,
+                       ddata->base + LPC32XX_TIMER_MCR);
+
+        /*
+         * Place timer in reset and program the delta in the match
+         * channel 0 (MR0).
+         */
+        writel_relaxed(LPC32XX_TIMER_TCR_CRST, ddata->base + LPC32XX_TIMER_TCR);
+        writel_relaxed(ddata->ticks_per_jiffy, ddata->base + LPC32XX_TIMER_MR0);
+        writel_relaxed(LPC32XX_TIMER_TCR_CEN, ddata->base + LPC32XX_TIMER_TCR);
+
+        return 0;
 }
 
 static irqreturn_t lpc32xx_clock_event_handler(int irq, void *dev_id)
@@ -108,11 +146,13 @@ static irqreturn_t lpc32xx_clock_event_handler(int irq, void *dev_id)
 static struct lpc32xx_clock_event_ddata lpc32xx_clk_event_ddata = {
         .evtdev = {
                 .name                   = "lpc3220 clockevent",
-                .features               = CLOCK_EVT_FEAT_ONESHOT,
+                .features               = CLOCK_EVT_FEAT_ONESHOT |
+                                          CLOCK_EVT_FEAT_PERIODIC,
                 .rating                 = 300,
                 .set_next_event         = lpc32xx_clkevt_next_event,
                 .set_state_shutdown     = lpc32xx_clkevt_shutdown,
                 .set_state_oneshot      = lpc32xx_clkevt_oneshot,
+                .set_state_periodic     = lpc32xx_clkevt_periodic,
         },
 };
 
@@ -162,6 +202,8 @@ static int __init lpc32xx_clocksource_init(struct device_node *np)
         }
 
         clocksource_timer_counter = base + LPC32XX_TIMER_TC;
+        lpc32xx_delay_timer.freq = rate;
+        register_current_timer_delay(&lpc32xx_delay_timer);
         sched_clock_register(lpc32xx_read_sched_clock, 32, rate);
 
         return 0;
@@ -210,18 +252,16 @@ static int __init lpc32xx_clockevent_init(struct device_node *np)
 
         /*
          * Disable timer and clear any pending interrupt (IR) on match
-         * channel 0 (MR0). Configure a compare match value of 1 on MR0
-         * and enable interrupt, reset on match and stop on match (MCR).
+         * channel 0 (MR0). Clear the prescaler as it's not used.
          */
         writel_relaxed(0, base + LPC32XX_TIMER_TCR);
+        writel_relaxed(0, base + LPC32XX_TIMER_PR);
         writel_relaxed(0, base + LPC32XX_TIMER_CTCR);
         writel_relaxed(LPC32XX_TIMER_IR_MR0INT, base + LPC32XX_TIMER_IR);
-        writel_relaxed(1, base + LPC32XX_TIMER_MR0);
-        writel_relaxed(LPC32XX_TIMER_MCR_MR0I | LPC32XX_TIMER_MCR_MR0R |
-                       LPC32XX_TIMER_MCR_MR0S, base + LPC32XX_TIMER_MCR);
 
         rate = clk_get_rate(clk);
         lpc32xx_clk_event_ddata.base = base;
+        lpc32xx_clk_event_ddata.ticks_per_jiffy = DIV_ROUND_CLOSEST(rate, HZ);
         clockevents_config_and_register(&lpc32xx_clk_event_ddata.evtdev,
                                         rate, 1, -1);
 
diff --git a/drivers/net/ethernet/intel/Kconfig b/drivers/net/ethernet/intel/Kconfig
index fa593dd3efe1..3772f3ac956e 100644
--- a/drivers/net/ethernet/intel/Kconfig
+++ b/drivers/net/ethernet/intel/Kconfig
@@ -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
diff --git a/drivers/net/ethernet/intel/e1000e/defines.h b/drivers/net/ethernet/intel/e1000e/defines.h
index f7c7804d79e5..0641c0098738 100644
--- a/drivers/net/ethernet/intel/e1000e/defines.h
+++ b/drivers/net/ethernet/intel/e1000e/defines.h
@@ -528,6 +528,11 @@
 #define E1000_RXCW_C          0x20000000        /* Receive config */
 #define E1000_RXCW_SYNCH      0x40000000        /* Receive config synch */
 
+/* HH Time Sync */
+#define E1000_TSYNCTXCTL_MAX_ALLOWED_DLY_MASK   0x0000F000 /* max delay */
+#define E1000_TSYNCTXCTL_SYNC_COMP              0x40000000 /* sync complete */
+#define E1000_TSYNCTXCTL_START_SYNC             0x80000000 /* initiate sync */
+
 #define E1000_TSYNCTXCTL_VALID          0x00000001 /* Tx timestamp valid */
 #define E1000_TSYNCTXCTL_ENABLED        0x00000010 /* enable Tx timestamping */
 
diff --git a/drivers/net/ethernet/intel/e1000e/ptp.c b/drivers/net/ethernet/intel/e1000e/ptp.c
index 25a0ad5102d6..e2ff3ef75d5d 100644
--- a/drivers/net/ethernet/intel/e1000e/ptp.c
+++ b/drivers/net/ethernet/intel/e1000e/ptp.c
@@ -26,6 +26,12 @@
 
 #include "e1000.h"
 
+#ifdef CONFIG_E1000E_HWTS
+#include <linux/clocksource.h>
+#include <linux/ktime.h>
+#include <asm/tsc.h>
+#endif
+
 /**
  * e1000e_phc_adjfreq - adjust the frequency of the hardware clock
  * @ptp: ptp clock structure
@@ -98,6 +104,78 @@ static int e1000e_phc_adjtime(struct ptp_clock_info *ptp, s64 delta)
         return 0;
 }
 
+#ifdef CONFIG_E1000E_HWTS
+#define MAX_HW_WAIT_COUNT (3)
+
+/**
+ * e1000e_phc_get_syncdevicetime - Callback given to timekeeping code reads system/device registers
+ * @device: current device time
+ * @system: system counter value read synchronously with device time
+ * @ctx: context provided by timekeeping code
+ *
+ * Read device and system (ART) clock simultaneously and return the corrected
+ * clock values in ns.
+ **/
+static int e1000e_phc_get_syncdevicetime(ktime_t *device,
+                                         struct system_counterval_t *system,
+                                         void *ctx)
+{
+        struct e1000_adapter *adapter = (struct e1000_adapter *)ctx;
+        struct e1000_hw *hw = &adapter->hw;
+        unsigned long flags;
+        int i;
+        u32 tsync_ctrl;
+        cycle_t dev_cycles;
+        cycle_t sys_cycles;
+
+        tsync_ctrl = er32(TSYNCTXCTL);
+        tsync_ctrl |= E1000_TSYNCTXCTL_START_SYNC |
+                E1000_TSYNCTXCTL_MAX_ALLOWED_DLY_MASK;
+        ew32(TSYNCTXCTL, tsync_ctrl);
+        for (i = 0; i < MAX_HW_WAIT_COUNT; ++i) {
+                udelay(1);
+                tsync_ctrl = er32(TSYNCTXCTL);
+                if (tsync_ctrl & E1000_TSYNCTXCTL_SYNC_COMP)
+                        break;
+        }
+
+        if (i == MAX_HW_WAIT_COUNT)
+                return -ETIMEDOUT;
+
+        dev_cycles = er32(SYSSTMPH);
+        dev_cycles <<= 32;
+        dev_cycles |= er32(SYSSTMPL);
+        spin_lock_irqsave(&adapter->systim_lock, flags);
+        *device = ns_to_ktime(timecounter_cyc2time(&adapter->tc, dev_cycles));
+        spin_unlock_irqrestore(&adapter->systim_lock, flags);
+
+        sys_cycles = er32(PLTSTMPH);
+        sys_cycles <<= 32;
+        sys_cycles |= er32(PLTSTMPL);
+        *system = convert_art_to_tsc(sys_cycles);
+
+        return 0;
+}
+
+/**
+ * e1000e_phc_getsynctime - Reads the current system/device cross timestamp
+ * @ptp: ptp clock structure
+ * @cts: structure containing timestamp
+ *
+ * Read device and system (ART) clock simultaneously and return the scaled
+ * clock values in ns.
+ **/
+static int e1000e_phc_getcrosststamp(struct ptp_clock_info *ptp,
+                                     struct system_device_crosststamp *xtstamp)
+{
+        struct e1000_adapter *adapter = container_of(ptp, struct e1000_adapter,
+                                                     ptp_clock_info);
+
+        return get_device_system_crosststamp(e1000e_phc_get_syncdevicetime,
+                                                adapter, NULL, xtstamp);
+}
+#endif/*CONFIG_E1000E_HWTS*/
+
 /**
  * e1000e_phc_gettime - Reads the current time from the hardware clock
  * @ptp: ptp clock structure
@@ -236,6 +314,13 @@ void e1000e_ptp_init(struct e1000_adapter *adapter)
                 break;
         }
 
+#ifdef CONFIG_E1000E_HWTS
+        /* CPU must have ART and GBe must be from Sunrise Point or greater */
+        if (hw->mac.type >= e1000_pch_spt && boot_cpu_has(X86_FEATURE_ART))
+                adapter->ptp_clock_info.getcrosststamp =
+                        e1000e_phc_getcrosststamp;
+#endif/*CONFIG_E1000E_HWTS*/
+
         INIT_DELAYED_WORK(&adapter->systim_overflow_work,
                           e1000e_systim_overflow_work);
 
diff --git a/drivers/net/ethernet/intel/e1000e/regs.h b/drivers/net/ethernet/intel/e1000e/regs.h
index 1d5e0b77062a..0cb4d365e5ad 100644
--- a/drivers/net/ethernet/intel/e1000e/regs.h
+++ b/drivers/net/ethernet/intel/e1000e/regs.h
@@ -245,6 +245,10 @@
 #define E1000_SYSTIML   0x0B600 /* System time register Low - RO */
 #define E1000_SYSTIMH   0x0B604 /* System time register High - RO */
 #define E1000_TIMINCA   0x0B608 /* Increment attributes register - RW */
+#define E1000_SYSSTMPL  0x0B648 /* HH Timesync system stamp low register */
+#define E1000_SYSSTMPH  0x0B64C /* HH Timesync system stamp hi register */
+#define E1000_PLTSTMPL  0x0B640 /* HH Timesync platform stamp low register */
+#define E1000_PLTSTMPH  0x0B644 /* HH Timesync platform stamp hi register */
 #define E1000_RXMTRL    0x0B634 /* Time sync Rx EtherType and Msg Type - RW */
 #define E1000_RXUDP     0x0B638 /* Time Sync Rx UDP Port - RW */
 
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index da7bae991552..579fd65299a0 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -22,6 +22,7 @@
 #include <linux/poll.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
+#include <linux/timekeeping.h>
 
 #include "ptp_private.h"
 
@@ -120,11 +121,13 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
         struct ptp_clock_caps caps;
         struct ptp_clock_request req;
         struct ptp_sys_offset *sysoff = NULL;
+        struct ptp_sys_offset_precise precise_offset;
         struct ptp_pin_desc pd;
         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
         struct ptp_clock_info *ops = ptp->info;
         struct ptp_clock_time *pct;
         struct timespec64 ts;
+        struct system_device_crosststamp xtstamp;
         int enable, err = 0;
         unsigned int i, pin_index;
 
@@ -138,6 +141,7 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
                 caps.n_per_out = ptp->info->n_per_out;
                 caps.pps = ptp->info->pps;
                 caps.n_pins = ptp->info->n_pins;
+                caps.cross_timestamping = ptp->info->getcrosststamp != NULL;
                 if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))
                         err = -EFAULT;
                 break;
@@ -180,6 +184,29 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
                 err = ops->enable(ops, &req, enable);
                 break;
 
+        case PTP_SYS_OFFSET_PRECISE:
+                if (!ptp->info->getcrosststamp) {
+                        err = -EOPNOTSUPP;
+                        break;
+                }
+                err = ptp->info->getcrosststamp(ptp->info, &xtstamp);
+                if (err)
+                        break;
+
+                ts = ktime_to_timespec64(xtstamp.device);
+                precise_offset.device.sec = ts.tv_sec;
+                precise_offset.device.nsec = ts.tv_nsec;
+                ts = ktime_to_timespec64(xtstamp.sys_realtime);
+                precise_offset.sys_realtime.sec = ts.tv_sec;
+                precise_offset.sys_realtime.nsec = ts.tv_nsec;
+                ts = ktime_to_timespec64(xtstamp.sys_monoraw);
+                precise_offset.sys_monoraw.sec = ts.tv_sec;
+                precise_offset.sys_monoraw.nsec = ts.tv_nsec;
+                if (copy_to_user((void __user *)arg, &precise_offset,
+                                 sizeof(precise_offset)))
+                        err = -EFAULT;
+                break;
+
         case PTP_SYS_OFFSET:
                 sysoff = kmalloc(sizeof(*sysoff), GFP_KERNEL);
                 if (!sysoff) {
diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index bdcf358dfce2..0d442e34c349 100644
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -190,9 +190,9 @@ extern void clockevents_config_and_register(struct clock_event_device *dev,
 extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
 
 static inline void
-clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
+clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 maxsec)
 {
-        return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC, freq, minsec);
+        return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC, freq, maxsec);
 }
 
 extern void clockevents_suspend(void);
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 6013021a3b39..a307bf62974f 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -118,6 +118,23 @@ struct clocksource {
 /* simplify initialization of mask field */
 #define CLOCKSOURCE_MASK(bits) (cycle_t)((bits) < 64 ? ((1ULL<<(bits))-1) : -1)
 
+static inline u32 clocksource_freq2mult(u32 freq, u32 shift_constant, u64 from)
+{
+        /*  freq = cyc/from
+         *  mult/2^shift  = ns/cyc
+         *  mult = ns/cyc * 2^shift
+         *  mult = from/freq * 2^shift
+         *  mult = from * 2^shift / freq
+         *  mult = (from<<shift) / freq
+         */
+        u64 tmp = ((u64)from) << shift_constant;
+
+        tmp += freq/2; /* round for do_div */
+        do_div(tmp, freq);
+
+        return (u32)tmp;
+}
+
 /**
  * clocksource_khz2mult - calculates mult from khz and shift
  * @khz:                Clocksource frequency in KHz
@@ -128,19 +145,7 @@ struct clocksource {
  */
 static inline u32 clocksource_khz2mult(u32 khz, u32 shift_constant)
 {
-        /*  khz = cyc/(Million ns)
-         *  mult/2^shift  = ns/cyc
-         *  mult = ns/cyc * 2^shift
-         *  mult = 1Million/khz * 2^shift
-         *  mult = 1000000 * 2^shift / khz
-         *  mult = (1000000<<shift) / khz
-         */
-        u64 tmp = ((u64)1000000) << shift_constant;
-
-        tmp += khz/2; /* round for do_div */
-        do_div(tmp, khz);
-
-        return (u32)tmp;
+        return clocksource_freq2mult(khz, shift_constant, NSEC_PER_MSEC);
 }
 
 /**
@@ -154,19 +159,7 @@ static inline u32 clocksource_khz2mult(u32 khz, u32 shift_constant)
  */
 static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant)
 {
-        /*  hz = cyc/(Billion ns)
-         *  mult/2^shift  = ns/cyc
-         *  mult = ns/cyc * 2^shift
-         *  mult = 1Billion/hz * 2^shift
-         *  mult = 1000000000 * 2^shift / hz
-         *  mult = (1000000000<<shift) / hz
-         */
-        u64 tmp = ((u64)1000000000) << shift_constant;
-
-        tmp += hz/2; /* round for do_div */
-        do_div(tmp, hz);
-
-        return (u32)tmp;
+        return clocksource_freq2mult(hz, shift_constant, NSEC_PER_SEC);
 }
 
 /**
diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h
index 54bf1484d41f..35ac903956c7 100644
--- a/include/linux/pps_kernel.h
+++ b/include/linux/pps_kernel.h
@@ -111,22 +111,17 @@ static inline void timespec_to_pps_ktime(struct pps_ktime *kt,
         kt->nsec = ts.tv_nsec;
 }
 
-#ifdef CONFIG_NTP_PPS
-
 static inline void pps_get_ts(struct pps_event_time *ts)
 {
-        ktime_get_raw_and_real_ts64(&ts->ts_raw, &ts->ts_real);
-}
+        struct system_time_snapshot snap;
 
-#else /* CONFIG_NTP_PPS */
-
-static inline void pps_get_ts(struct pps_event_time *ts)
-{
-        ktime_get_real_ts64(&ts->ts_real);
+        ktime_get_snapshot(&snap);
+        ts->ts_real = ktime_to_timespec64(snap.real);
+#ifdef CONFIG_NTP_PPS
+        ts->ts_raw = ktime_to_timespec64(snap.raw);
+#endif
 }
 
-#endif /* CONFIG_NTP_PPS */
-
 /* Subtract known time delay from PPS event time(s) */
 static inline void pps_sub_ts(struct pps_event_time *ts, struct timespec64 delta)
 {
diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index b8b73066d137..6b15e168148a 100644
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -38,6 +38,7 @@ struct ptp_clock_request {
         };
 };
 
+struct system_device_crosststamp;
 /**
  * struct ptp_clock_info - decribes a PTP hardware clock
  *
@@ -67,6 +68,11 @@ struct ptp_clock_request {
  * @gettime64:  Reads the current time from the hardware clock.
  *              parameter ts: Holds the result.
  *
+ * @getcrosststamp:  Reads the current time from the hardware clock and
+ *                   system clock simultaneously.
+ *                   parameter cts: Contains timestamp (device,system) pair,
+ *                   where system time is realtime and monotonic.
+ *
  * @settime64:  Set the current time on the hardware clock.
  *              parameter ts: Time value to set.
  *
@@ -105,6 +111,8 @@ struct ptp_clock_info {
         int (*adjfreq)(struct ptp_clock_info *ptp, s32 delta);
         int (*adjtime)(struct ptp_clock_info *ptp, s64 delta);
         int (*gettime64)(struct ptp_clock_info *ptp, struct timespec64 *ts);
+        int (*getcrosststamp)(struct ptp_clock_info *ptp,
+                              struct system_device_crosststamp *cts);
         int (*settime64)(struct ptp_clock_info *p, const struct timespec64 *ts);
         int (*enable)(struct ptp_clock_info *ptp,
                       struct ptp_clock_request *request, int on);
diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h
index 25247220b4b7..e88005459035 100644
--- a/include/linux/timekeeper_internal.h
+++ b/include/linux/timekeeper_internal.h
@@ -50,6 +50,7 @@ struct tk_read_base {
  * @offs_tai:           Offset clock monotonic -> clock tai
  * @tai_offset:         The current UTC to TAI offset in seconds
  * @clock_was_set_seq:  The sequence number of clock was set events
+ * @cs_was_changed_seq: The sequence number of clocksource change events
  * @next_leap_ktime:    CLOCK_MONOTONIC time value of a pending leap-second
  * @raw_time:           Monotonic raw base time in timespec64 format
  * @cycle_interval:     Number of clock cycles in one NTP interval
@@ -91,6 +92,7 @@ struct timekeeper {
         ktime_t                 offs_tai;
         s32                     tai_offset;
         unsigned int            clock_was_set_seq;
+        u8                      cs_was_changed_seq;
         ktime_t                 next_leap_ktime;
         struct timespec64       raw_time;
 
diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index ec89d846324c..96f37bee3bc1 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -267,6 +267,64 @@ extern void ktime_get_raw_and_real_ts64(struct timespec64 *ts_raw,
                                         struct timespec64 *ts_real);
 
 /*
+ * struct system_time_snapshot - simultaneous raw/real time capture with
+ *      counter value
+ * @cycles:     Clocksource counter value to produce the system times
+ * @real:       Realtime system time
+ * @raw:        Monotonic raw system time
+ * @clock_was_set_seq:  The sequence number of clock was set events
+ * @cs_was_changed_seq: The sequence number of clocksource change events
+ */
+struct system_time_snapshot {
+        cycle_t         cycles;
+        ktime_t         real;
+        ktime_t         raw;
+        unsigned int    clock_was_set_seq;
+        u8              cs_was_changed_seq;
+};
+
+/*
+ * struct system_device_crosststamp - system/device cross-timestamp
+ *      (syncronized capture)
+ * @device:             Device time
+ * @sys_realtime:       Realtime simultaneous with device time
+ * @sys_monoraw:        Monotonic raw simultaneous with device time
+ */
+struct system_device_crosststamp {
+        ktime_t device;
+        ktime_t sys_realtime;
+        ktime_t sys_monoraw;
+};
+
+/*
+ * struct system_counterval_t - system counter value with the pointer to the
+ *      corresponding clocksource
+ * @cycles:     System counter value
+ * @cs:         Clocksource corresponding to system counter value. Used by
+ *      timekeeping code to verify comparibility of two cycle values
+ */
+struct system_counterval_t {
+        cycle_t                 cycles;
+        struct clocksource      *cs;
+};
+
+/*
+ * Get cross timestamp between system clock and device clock
+ */
+extern int get_device_system_crosststamp(
+                        int (*get_time_fn)(ktime_t *device_time,
+                                struct system_counterval_t *system_counterval,
+                                void *ctx),
+                        void *ctx,
+                        struct system_time_snapshot *history,
+                        struct system_device_crosststamp *xtstamp);
+
+/*
+ * Simultaneously snapshot realtime and monotonic raw clocks
+ */
+extern void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot);
+
+/*
  * Persistent clock related interfaces
  */
 extern int persistent_clock_is_local;
diff --git a/include/uapi/linux/ptp_clock.h b/include/uapi/linux/ptp_clock.h
index f0b7bfe5da92..ac6dded80ffa 100644
--- a/include/uapi/linux/ptp_clock.h
+++ b/include/uapi/linux/ptp_clock.h
@@ -51,7 +51,9 @@ struct ptp_clock_caps {
         int n_per_out; /* Number of programmable periodic signals. */
         int pps;       /* Whether the clock supports a PPS callback. */
         int n_pins;    /* Number of input/output pins. */
-        int rsv[14];   /* Reserved for future use. */
+        /* Whether the clock supports precise system-device cross timestamps */
+        int cross_timestamping;
+        int rsv[13];   /* Reserved for future use. */
 };
 
 struct ptp_extts_request {
@@ -81,6 +83,13 @@ struct ptp_sys_offset {
         struct ptp_clock_time ts[2 * PTP_MAX_SAMPLES + 1];
 };
 
+struct ptp_sys_offset_precise {
+        struct ptp_clock_time device;
+        struct ptp_clock_time sys_realtime;
+        struct ptp_clock_time sys_monoraw;
+        unsigned int rsv[4];    /* Reserved for future use. */
+};
+
 enum ptp_pin_function {
         PTP_PF_NONE,
         PTP_PF_EXTTS,
@@ -124,6 +133,8 @@ struct ptp_pin_desc {
 #define PTP_SYS_OFFSET     _IOW(PTP_CLK_MAGIC, 5, struct ptp_sys_offset)
 #define PTP_PIN_GETFUNC    _IOWR(PTP_CLK_MAGIC, 6, struct ptp_pin_desc)
 #define PTP_PIN_SETFUNC    _IOW(PTP_CLK_MAGIC, 7, struct ptp_pin_desc)
+#define PTP_SYS_OFFSET_PRECISE \
+        _IOWR(PTP_CLK_MAGIC, 8, struct ptp_sys_offset_precise)
 
 struct ptp_extts_event {
         struct ptp_clock_time t; /* Time event occured. */
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 664de539299b..56ece145a814 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -323,13 +323,42 @@ static void clocksource_enqueue_watchdog(struct clocksource *cs)
                 /* cs is a watchdog. */
                 if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
                         cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
+        }
+        spin_unlock_irqrestore(&watchdog_lock, flags);
+}
+
+static void clocksource_select_watchdog(bool fallback)
+{
+        struct clocksource *cs, *old_wd;
+        unsigned long flags;
+
+        spin_lock_irqsave(&watchdog_lock, flags);
+        /* save current watchdog */
+        old_wd = watchdog;
+        if (fallback)
+                watchdog = NULL;
+
+        list_for_each_entry(cs, &clocksource_list, list) {
+                /* cs is a clocksource to be watched. */
+                if (cs->flags & CLOCK_SOURCE_MUST_VERIFY)
+                        continue;
+
+                /* Skip current if we were requested for a fallback. */
+                if (fallback && cs == old_wd)
+                        continue;
+
                 /* Pick the best watchdog. */
-                if (!watchdog || cs->rating > watchdog->rating) {
+                if (!watchdog || cs->rating > watchdog->rating)
                         watchdog = cs;
-                        /* Reset watchdog cycles */
-                        clocksource_reset_watchdog();
-                }
         }
+        /* If we failed to find a fallback restore the old one. */
+        if (!watchdog)
+                watchdog = old_wd;
+
+        /* If we changed the watchdog we need to reset cycles. */
+        if (watchdog != old_wd)
+                clocksource_reset_watchdog();
+
         /* Check if the watchdog timer needs to be started. */
         clocksource_start_watchdog();
         spin_unlock_irqrestore(&watchdog_lock, flags);
@@ -404,6 +433,7 @@ static void clocksource_enqueue_watchdog(struct clocksource *cs)
                 cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
 }
 
+static void clocksource_select_watchdog(bool fallback) { }
 static inline void clocksource_dequeue_watchdog(struct clocksource *cs) { }
 static inline void clocksource_resume_watchdog(void) { }
 static inline int __clocksource_watchdog_kthread(void) { return 0; }
@@ -736,6 +766,7 @@ int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq)
         clocksource_enqueue(cs);
         clocksource_enqueue_watchdog(cs);
         clocksource_select();
+        clocksource_select_watchdog(false);
         mutex_unlock(&clocksource_mutex);
         return 0;
 }
@@ -758,6 +789,7 @@ void clocksource_change_rating(struct clocksource *cs, int rating)
         mutex_lock(&clocksource_mutex);
         __clocksource_change_rating(cs, rating);
         clocksource_select();
+        clocksource_select_watchdog(false);
         mutex_unlock(&clocksource_mutex);
 }
 EXPORT_SYMBOL(clocksource_change_rating);
@@ -767,12 +799,12 @@ EXPORT_SYMBOL(clocksource_change_rating);
  */
 static int clocksource_unbind(struct clocksource *cs)
 {
-        /*
-         * I really can't convince myself to support this on hardware
-         * designed by lobotomized monkeys.
-         */
-        if (clocksource_is_watchdog(cs))
-                return -EBUSY;
+        if (clocksource_is_watchdog(cs)) {
+                /* Select and try to install a replacement watchdog. */
+                clocksource_select_watchdog(true);
+                if (clocksource_is_watchdog(cs))
+                        return -EBUSY;
+        }
 
         if (cs == curr_clocksource) {
                 /* Select and try to install a replacement clock source */
diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c
index 347fecf86a3f..555e21f7b966 100644
--- a/kernel/time/jiffies.c
+++ b/kernel/time/jiffies.c
@@ -68,7 +68,7 @@ static struct clocksource clocksource_jiffies = {
         .name           = "jiffies",
         .rating         = 1, /* lowest valid rating*/
         .read           = jiffies_read,
-        .mask           = 0xffffffff, /*32bits*/
+        .mask           = CLOCKSOURCE_MASK(32),
         .mult           = NSEC_PER_JIFFY << JIFFIES_SHIFT, /* details above */
         .shift          = JIFFIES_SHIFT,
         .max_cycles     = 10,
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 34b4cedfa80d..9c629bbed572 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -233,6 +233,7 @@ static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
         u64 tmp, ntpinterval;
         struct clocksource *old_clock;
 
+        ++tk->cs_was_changed_seq;
         old_clock = tk->tkr_mono.clock;
         tk->tkr_mono.clock = clock;
         tk->tkr_mono.read = clock->read;
@@ -298,17 +299,34 @@ u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
 static inline u32 arch_gettimeoffset(void) { return 0; }
 #endif
 
+static inline s64 timekeeping_delta_to_ns(struct tk_read_base *tkr,
+                                          cycle_t delta)
+{
+        s64 nsec;
+
+        nsec = delta * tkr->mult + tkr->xtime_nsec;
+        nsec >>= tkr->shift;
+
+        /* If arch requires, add in get_arch_timeoffset() */
+        return nsec + arch_gettimeoffset();
+}
+
 static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
 {
         cycle_t delta;
-        s64 nsec;
 
         delta = timekeeping_get_delta(tkr);
+        return timekeeping_delta_to_ns(tkr, delta);
+}
 
-        nsec = (delta * tkr->mult + tkr->xtime_nsec) >> tkr->shift;
+static inline s64 timekeeping_cycles_to_ns(struct tk_read_base *tkr,
+                                            cycle_t cycles)
+{
+        cycle_t delta;
 
-        /* If arch requires, add in get_arch_timeoffset() */
-        return nsec + arch_gettimeoffset();
+        /* calculate the delta since the last update_wall_time */
+        delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
+        return timekeeping_delta_to_ns(tkr, delta);
 }
 
 /**
@@ -857,44 +875,262 @@ time64_t __ktime_get_real_seconds(void)
         return tk->xtime_sec;
 }
 
+/**
+ * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
+ * @systime_snapshot:   pointer to struct receiving the system time snapshot
+ */
+void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
+{
+        struct timekeeper *tk = &tk_core.timekeeper;
+        unsigned long seq;
+        ktime_t base_raw;
+        ktime_t base_real;
+        s64 nsec_raw;
+        s64 nsec_real;
+        cycle_t now;
 
-#ifdef CONFIG_NTP_PPS
+        WARN_ON_ONCE(timekeeping_suspended);
+
+        do {
+                seq = read_seqcount_begin(&tk_core.seq);
+
+                now = tk->tkr_mono.read(tk->tkr_mono.clock);
+                systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq;
+                systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq;
+                base_real = ktime_add(tk->tkr_mono.base,
+                                      tk_core.timekeeper.offs_real);
+                base_raw = tk->tkr_raw.base;
+                nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
+                nsec_raw  = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
+        } while (read_seqcount_retry(&tk_core.seq, seq));
+
+        systime_snapshot->cycles = now;
+        systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
+        systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
+}
+EXPORT_SYMBOL_GPL(ktime_get_snapshot);
+
+/* Scale base by mult/div checking for overflow */
+static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
+{
+        u64 tmp, rem;
+
+        tmp = div64_u64_rem(*base, div, &rem);
+
+        if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) ||
+            ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem)))
+                return -EOVERFLOW;
+        tmp *= mult;
+        rem *= mult;
+
+        do_div(rem, div);
+        *base = tmp + rem;
+        return 0;
+}
 
 /**
- * ktime_get_raw_and_real_ts64 - get day and raw monotonic time in timespec format
- * @ts_raw:     pointer to the timespec to be set to raw monotonic time
- * @ts_real:    pointer to the timespec to be set to the time of day
+ * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
+ * @history:                    Snapshot representing start of history
+ * @partial_history_cycles:     Cycle offset into history (fractional part)
+ * @total_history_cycles:       Total history length in cycles
+ * @discontinuity:              True indicates clock was set on history period
+ * @ts:                         Cross timestamp that should be adjusted using
+ *      partial/total ratio
  *
- * This function reads both the time of day and raw monotonic time at the
- * same time atomically and stores the resulting timestamps in timespec
- * format.
+ * Helper function used by get_device_system_crosststamp() to correct the
+ * crosstimestamp corresponding to the start of the current interval to the
+ * system counter value (timestamp point) provided by the driver. The
+ * total_history_* quantities are the total history starting at the provided
+ * reference point and ending at the start of the current interval. The cycle
+ * count between the driver timestamp point and the start of the current
+ * interval is partial_history_cycles.
  */
-void ktime_get_raw_and_real_ts64(struct timespec64 *ts_raw, struct timespec64 *ts_real)
+static int adjust_historical_crosststamp(struct system_time_snapshot *history,
+                                         cycle_t partial_history_cycles,
+                                         cycle_t total_history_cycles,
+                                         bool discontinuity,
+                                         struct system_device_crosststamp *ts)
 {
         struct timekeeper *tk = &tk_core.timekeeper;
-        unsigned long seq;
-        s64 nsecs_raw, nsecs_real;
+        u64 corr_raw, corr_real;
+        bool interp_forward;
+        int ret;
 
-        WARN_ON_ONCE(timekeeping_suspended);
+        if (total_history_cycles == 0 || partial_history_cycles == 0)
+                return 0;
+
+        /* Interpolate shortest distance from beginning or end of history */
+        interp_forward = partial_history_cycles > total_history_cycles/2 ?
+                true : false;
+        partial_history_cycles = interp_forward ?
+                total_history_cycles - partial_history_cycles :
+                partial_history_cycles;
+
+        /*
+         * Scale the monotonic raw time delta by:
+         *      partial_history_cycles / total_history_cycles
+         */
+        corr_raw = (u64)ktime_to_ns(
+                ktime_sub(ts->sys_monoraw, history->raw));
+        ret = scale64_check_overflow(partial_history_cycles,
+                                     total_history_cycles, &corr_raw);
+        if (ret)
+                return ret;
+
+        /*
+         * If there is a discontinuity in the history, scale monotonic raw
+         *      correction by:
+         *      mult(real)/mult(raw) yielding the realtime correction
+         * Otherwise, calculate the realtime correction similar to monotonic
+         *      raw calculation
+         */
+        if (discontinuity) {
+                corr_real = mul_u64_u32_div
+                        (corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult);
+        } else {
+                corr_real = (u64)ktime_to_ns(
+                        ktime_sub(ts->sys_realtime, history->real));
+                ret = scale64_check_overflow(partial_history_cycles,
+                                             total_history_cycles, &corr_real);
+                if (ret)
+                        return ret;
+        }
+
+        /* Fixup monotonic raw and real time time values */
+        if (interp_forward) {
+                ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw);
+                ts->sys_realtime = ktime_add_ns(history->real, corr_real);
+        } else {
+                ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw);
+                ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real);
+        }
+
+        return 0;
+}
+
+/*
+ * cycle_between - true if test occurs chronologically between before and after
+ */
+static bool cycle_between(cycle_t before, cycle_t test, cycle_t after)
+{
+        if (test > before && test < after)
+                return true;
+        if (test < before && before > after)
+                return true;
+        return false;
+}
+
+/**
+ * get_device_system_crosststamp - Synchronously capture system/device timestamp
+ * @get_time_fn:        Callback to get simultaneous device time and
+ *      system counter from the device driver
+ * @ctx:                Context passed to get_time_fn()
+ * @history_begin:      Historical reference point used to interpolate system
+ *      time when counter provided by the driver is before the current interval
+ * @xtstamp:            Receives simultaneously captured system and device time
+ *
+ * Reads a timestamp from a device and correlates it to system time
+ */
+int get_device_system_crosststamp(int (*get_time_fn)
+                                  (ktime_t *device_time,
+                                   struct system_counterval_t *sys_counterval,
+                                   void *ctx),
+                                  void *ctx,
+                                  struct system_time_snapshot *history_begin,
+                                  struct system_device_crosststamp *xtstamp)
+{
+        struct system_counterval_t system_counterval;
+        struct timekeeper *tk = &tk_core.timekeeper;
+        cycle_t cycles, now, interval_start;
+        unsigned int clock_was_set_seq = 0;
+        ktime_t base_real, base_raw;
+        s64 nsec_real, nsec_raw;
+        u8 cs_was_changed_seq;
+        unsigned long seq;
+        bool do_interp;
+        int ret;
 
         do {
                 seq = read_seqcount_begin(&tk_core.seq);
+                /*
+                 * Try to synchronously capture device time and a system
+                 * counter value calling back into the device driver
+                 */
+                ret = get_time_fn(&xtstamp->device, &system_counterval, ctx);
+                if (ret)
+                        return ret;
+
+                /*
+                 * Verify that the clocksource associated with the captured
+                 * system counter value is the same as the currently installed
+                 * timekeeper clocksource
+                 */
+                if (tk->tkr_mono.clock != system_counterval.cs)
+                        return -ENODEV;
+                cycles = system_counterval.cycles;
 
-                *ts_raw = tk->raw_time;
-                ts_real->tv_sec = tk->xtime_sec;
-                ts_real->tv_nsec = 0;
+                /*
+                 * Check whether the system counter value provided by the
+                 * device driver is on the current timekeeping interval.
+                 */
+                now = tk->tkr_mono.read(tk->tkr_mono.clock);
+                interval_start = tk->tkr_mono.cycle_last;
+                if (!cycle_between(interval_start, cycles, now)) {
+                        clock_was_set_seq = tk->clock_was_set_seq;
+                        cs_was_changed_seq = tk->cs_was_changed_seq;
+                        cycles = interval_start;
+                        do_interp = true;
+                } else {
+                        do_interp = false;
+                }
 
-                nsecs_raw  = timekeeping_get_ns(&tk->tkr_raw);
-                nsecs_real = timekeeping_get_ns(&tk->tkr_mono);
+                base_real = ktime_add(tk->tkr_mono.base,
+                                      tk_core.timekeeper.offs_real);
+                base_raw = tk->tkr_raw.base;
 
+                nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono,
+                                                     system_counterval.cycles);
+                nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw,
+                                                    system_counterval.cycles);
         } while (read_seqcount_retry(&tk_core.seq, seq));
 
-        timespec64_add_ns(ts_raw, nsecs_raw);
-        timespec64_add_ns(ts_real, nsecs_real);
-}
-EXPORT_SYMBOL(ktime_get_raw_and_real_ts64);
+        xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real);
+        xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw);
 
-#endif /* CONFIG_NTP_PPS */
+        /*
+         * Interpolate if necessary, adjusting back from the start of the
+         * current interval
+         */
+        if (do_interp) {
+                cycle_t partial_history_cycles, total_history_cycles;
+                bool discontinuity;
+
+                /*
+                 * Check that the counter value occurs after the provided
+                 * history reference and that the history doesn't cross a
+                 * clocksource change
+                 */
+                if (!history_begin ||
+                    !cycle_between(history_begin->cycles,
+                                   system_counterval.cycles, cycles) ||
+                    history_begin->cs_was_changed_seq != cs_was_changed_seq)
+                        return -EINVAL;
+                partial_history_cycles = cycles - system_counterval.cycles;
+                total_history_cycles = cycles - history_begin->cycles;
+                discontinuity =
+                        history_begin->clock_was_set_seq != clock_was_set_seq;
+
+                ret = adjust_historical_crosststamp(history_begin,
+                                                    partial_history_cycles,
+                                                    total_history_cycles,
+                                                    discontinuity, xtstamp);
+                if (ret)
+                        return ret;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(get_device_system_crosststamp);
 
 /**
  * do_gettimeofday - Returns the time of day in a timeval