Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1791 insertions, 0 deletions

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
new file mode 100644
index 000000000..fee1c4bf1
--- /dev/null
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -0,0 +1,1791 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/drivers/clocksource/arm_arch_timer.c
+ *
+ *  Copyright (C) 2011 ARM Ltd.
+ *  All Rights Reserved
+ */
+
+#define pr_fmt(fmt) 	"arch_timer: " fmt
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/smp.h>
+#include <linux/cpu.h>
+#include <linux/cpu_pm.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/clocksource_ids.h>
+#include <linux/interrupt.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/sched/clock.h>
+#include <linux/sched_clock.h>
+#include <linux/acpi.h>
+#include <linux/arm-smccc.h>
+#include <linux/ptp_kvm.h>
+
+#include <asm/arch_timer.h>
+#include <asm/virt.h>
+
+#include <clocksource/arm_arch_timer.h>
+
+#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 CNTPCT_LO	0x00
+#define CNTVCT_LO	0x08
+#define CNTFRQ		0x10
+#define CNTP_CVAL_LO	0x20
+#define CNTP_CTL	0x2c
+#define CNTV_CVAL_LO	0x30
+#define CNTV_CTL	0x3c
+
+/*
+ * The minimum amount of time a generic counter is guaranteed to not roll over
+ * (40 years)
+ */
+#define MIN_ROLLOVER_SECS	(40ULL * 365 * 24 * 3600)
+
+static unsigned arch_timers_present __initdata;
+
+struct arch_timer {
+	void __iomem *base;
+	struct clock_event_device evt;
+};
+
+static struct arch_timer *arch_timer_mem __ro_after_init;
+
+#define to_arch_timer(e) container_of(e, struct arch_timer, evt)
+
+static u32 arch_timer_rate __ro_after_init;
+static int arch_timer_ppi[ARCH_TIMER_MAX_TIMER_PPI] __ro_after_init;
+
+static const char *arch_timer_ppi_names[ARCH_TIMER_MAX_TIMER_PPI] = {
+	[ARCH_TIMER_PHYS_SECURE_PPI]	= "sec-phys",
+	[ARCH_TIMER_PHYS_NONSECURE_PPI]	= "phys",
+	[ARCH_TIMER_VIRT_PPI]		= "virt",
+	[ARCH_TIMER_HYP_PPI]		= "hyp-phys",
+	[ARCH_TIMER_HYP_VIRT_PPI]	= "hyp-virt",
+};
+
+static struct clock_event_device __percpu *arch_timer_evt;
+
+static enum arch_timer_ppi_nr arch_timer_uses_ppi __ro_after_init = ARCH_TIMER_VIRT_PPI;
+static bool arch_timer_c3stop __ro_after_init;
+static bool arch_timer_mem_use_virtual __ro_after_init;
+static bool arch_counter_suspend_stop __ro_after_init;
+#ifdef CONFIG_GENERIC_GETTIMEOFDAY
+static enum vdso_clock_mode vdso_default = VDSO_CLOCKMODE_ARCHTIMER;
+#else
+static enum vdso_clock_mode vdso_default = VDSO_CLOCKMODE_NONE;
+#endif /* CONFIG_GENERIC_GETTIMEOFDAY */
+
+static cpumask_t evtstrm_available = CPU_MASK_NONE;
+static bool evtstrm_enable __ro_after_init = IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM);
+
+static int __init early_evtstrm_cfg(char *buf)
+{
+	return strtobool(buf, &evtstrm_enable);
+}
+early_param("clocksource.arm_arch_timer.evtstrm", early_evtstrm_cfg);
+
+/*
+ * Makes an educated guess at a valid counter width based on the Generic Timer
+ * specification. Of note:
+ *   1) the system counter is at least 56 bits wide
+ *   2) a roll-over time of not less than 40 years
+ *
+ * See 'ARM DDI 0487G.a D11.1.2 ("The system counter")' for more details.
+ */
+static int arch_counter_get_width(void)
+{
+	u64 min_cycles = MIN_ROLLOVER_SECS * arch_timer_rate;
+
+	/* guarantee the returned width is within the valid range */
+	return clamp_val(ilog2(min_cycles - 1) + 1, 56, 64);
+}
+
+/*
+ * Architected system timer support.
+ */
+
+static __always_inline
+void arch_timer_reg_write(int access, enum arch_timer_reg reg, u64 val,
+			  struct clock_event_device *clk)
+{
+	if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
+		struct arch_timer *timer = to_arch_timer(clk);
+		switch (reg) {
+		case ARCH_TIMER_REG_CTRL:
+			writel_relaxed((u32)val, timer->base + CNTP_CTL);
+			break;
+		case ARCH_TIMER_REG_CVAL:
+			/*
+			 * Not guaranteed to be atomic, so the timer
+			 * must be disabled at this point.
+			 */
+			writeq_relaxed(val, timer->base + CNTP_CVAL_LO);
+			break;
+		default:
+			BUILD_BUG();
+		}
+	} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
+		struct arch_timer *timer = to_arch_timer(clk);
+		switch (reg) {
+		case ARCH_TIMER_REG_CTRL:
+			writel_relaxed((u32)val, timer->base + CNTV_CTL);
+			break;
+		case ARCH_TIMER_REG_CVAL:
+			/* Same restriction as above */
+			writeq_relaxed(val, timer->base + CNTV_CVAL_LO);
+			break;
+		default:
+			BUILD_BUG();
+		}
+	} else {
+		arch_timer_reg_write_cp15(access, reg, val);
+	}
+}
+
+static __always_inline
+u32 arch_timer_reg_read(int access, enum arch_timer_reg reg,
+			struct clock_event_device *clk)
+{
+	u32 val;
+
+	if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
+		struct arch_timer *timer = to_arch_timer(clk);
+		switch (reg) {
+		case ARCH_TIMER_REG_CTRL:
+			val = readl_relaxed(timer->base + CNTP_CTL);
+			break;
+		default:
+			BUILD_BUG();
+		}
+	} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
+		struct arch_timer *timer = to_arch_timer(clk);
+		switch (reg) {
+		case ARCH_TIMER_REG_CTRL:
+			val = readl_relaxed(timer->base + CNTV_CTL);
+			break;
+		default:
+			BUILD_BUG();
+		}
+	} else {
+		val = arch_timer_reg_read_cp15(access, reg);
+	}
+
+	return val;
+}
+
+static notrace u64 arch_counter_get_cntpct_stable(void)
+{
+	return __arch_counter_get_cntpct_stable();
+}
+
+static notrace u64 arch_counter_get_cntpct(void)
+{
+	return __arch_counter_get_cntpct();
+}
+
+static notrace u64 arch_counter_get_cntvct_stable(void)
+{
+	return __arch_counter_get_cntvct_stable();
+}
+
+static notrace u64 arch_counter_get_cntvct(void)
+{
+	return __arch_counter_get_cntvct();
+}
+
+/*
+ * Default to cp15 based access because arm64 uses this function for
+ * sched_clock() before DT is probed and the cp15 method is guaranteed
+ * to exist on arm64. arm doesn't use this before DT is probed so even
+ * if we don't have the cp15 accessors we won't have a problem.
+ */
+u64 (*arch_timer_read_counter)(void) __ro_after_init = arch_counter_get_cntvct;
+EXPORT_SYMBOL_GPL(arch_timer_read_counter);
+
+static u64 arch_counter_read(struct clocksource *cs)
+{
+	return arch_timer_read_counter();
+}
+
+static u64 arch_counter_read_cc(const struct cyclecounter *cc)
+{
+	return arch_timer_read_counter();
+}
+
+static struct clocksource clocksource_counter = {
+	.name	= "arch_sys_counter",
+	.id	= CSID_ARM_ARCH_COUNTER,
+	.rating	= 400,
+	.read	= arch_counter_read,
+	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static struct cyclecounter cyclecounter __ro_after_init = {
+	.read	= arch_counter_read_cc,
+};
+
+struct ate_acpi_oem_info {
+	char oem_id[ACPI_OEM_ID_SIZE + 1];
+	char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];
+	u32 oem_revision;
+};
+
+#ifdef CONFIG_FSL_ERRATUM_A008585
+/*
+ * The number of retries is an arbitrary value well beyond the highest number
+ * of iterations the loop has been observed to take.
+ */
+#define __fsl_a008585_read_reg(reg) ({			\
+	u64 _old, _new;					\
+	int _retries = 200;				\
+							\
+	do {						\
+		_old = read_sysreg(reg);		\
+		_new = read_sysreg(reg);		\
+		_retries--;				\
+	} while (unlikely(_old != _new) && _retries);	\
+							\
+	WARN_ON_ONCE(!_retries);			\
+	_new;						\
+})
+
+static u64 notrace fsl_a008585_read_cntpct_el0(void)
+{
+	return __fsl_a008585_read_reg(cntpct_el0);
+}
+
+static u64 notrace fsl_a008585_read_cntvct_el0(void)
+{
+	return __fsl_a008585_read_reg(cntvct_el0);
+}
+#endif
+
+#ifdef CONFIG_HISILICON_ERRATUM_161010101
+/*
+ * Verify whether the value of the second read is larger than the first by
+ * less than 32 is the only way to confirm the value is correct, so clear the
+ * lower 5 bits to check whether the difference is greater than 32 or not.
+ * Theoretically the erratum should not occur more than twice in succession
+ * when reading the system counter, but it is possible that some interrupts
+ * may lead to more than twice read errors, triggering the warning, so setting
+ * the number of retries far beyond the number of iterations the loop has been
+ * observed to take.
+ */
+#define __hisi_161010101_read_reg(reg) ({				\
+	u64 _old, _new;						\
+	int _retries = 50;					\
+								\
+	do {							\
+		_old = read_sysreg(reg);			\
+		_new = read_sysreg(reg);			\
+		_retries--;					\
+	} while (unlikely((_new - _old) >> 5) && _retries);	\
+								\
+	WARN_ON_ONCE(!_retries);				\
+	_new;							\
+})
+
+static u64 notrace hisi_161010101_read_cntpct_el0(void)
+{
+	return __hisi_161010101_read_reg(cntpct_el0);
+}
+
+static u64 notrace hisi_161010101_read_cntvct_el0(void)
+{
+	return __hisi_161010101_read_reg(cntvct_el0);
+}
+
+static struct ate_acpi_oem_info hisi_161010101_oem_info[] = {
+	/*
+	 * Note that trailing spaces are required to properly match
+	 * the OEM table information.
+	 */
+	{
+		.oem_id		= "HISI  ",
+		.oem_table_id	= "HIP05   ",
+		.oem_revision	= 0,
+	},
+	{
+		.oem_id		= "HISI  ",
+		.oem_table_id	= "HIP06   ",
+		.oem_revision	= 0,
+	},
+	{
+		.oem_id		= "HISI  ",
+		.oem_table_id	= "HIP07   ",
+		.oem_revision	= 0,
+	},
+	{ /* Sentinel indicating the end of the OEM array */ },
+};
+#endif
+
+#ifdef CONFIG_ARM64_ERRATUM_858921
+static u64 notrace arm64_858921_read_cntpct_el0(void)
+{
+	u64 old, new;
+
+	old = read_sysreg(cntpct_el0);
+	new = read_sysreg(cntpct_el0);
+	return (((old ^ new) >> 32) & 1) ? old : new;
+}
+
+static u64 notrace arm64_858921_read_cntvct_el0(void)
+{
+	u64 old, new;
+
+	old = read_sysreg(cntvct_el0);
+	new = read_sysreg(cntvct_el0);
+	return (((old ^ new) >> 32) & 1) ? old : new;
+}
+#endif
+
+#ifdef CONFIG_SUN50I_ERRATUM_UNKNOWN1
+/*
+ * The low bits of the counter registers are indeterminate while bit 10 or
+ * greater is rolling over. Since the counter value can jump both backward
+ * (7ff -> 000 -> 800) and forward (7ff -> fff -> 800), ignore register values
+ * with all ones or all zeros in the low bits. Bound the loop by the maximum
+ * number of CPU cycles in 3 consecutive 24 MHz counter periods.
+ */
+#define __sun50i_a64_read_reg(reg) ({					\
+	u64 _val;							\
+	int _retries = 150;						\
+									\
+	do {								\
+		_val = read_sysreg(reg);				\
+		_retries--;						\
+	} while (((_val + 1) & GENMASK(8, 0)) <= 1 && _retries);	\
+									\
+	WARN_ON_ONCE(!_retries);					\
+	_val;								\
+})
+
+static u64 notrace sun50i_a64_read_cntpct_el0(void)
+{
+	return __sun50i_a64_read_reg(cntpct_el0);
+}
+
+static u64 notrace sun50i_a64_read_cntvct_el0(void)
+{
+	return __sun50i_a64_read_reg(cntvct_el0);
+}
+#endif
+
+#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
+DEFINE_PER_CPU(const struct arch_timer_erratum_workaround *, timer_unstable_counter_workaround);
+EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround);
+
+static atomic_t timer_unstable_counter_workaround_in_use = ATOMIC_INIT(0);
+
+/*
+ * Force the inlining of this function so that the register accesses
+ * can be themselves correctly inlined.
+ */
+static __always_inline
+void erratum_set_next_event_generic(const int access, unsigned long evt,
+				    struct clock_event_device *clk)
+{
+	unsigned long ctrl;
+	u64 cval;
+
+	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
+	ctrl |= ARCH_TIMER_CTRL_ENABLE;
+	ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
+
+	if (access == ARCH_TIMER_PHYS_ACCESS) {
+		cval = evt + arch_counter_get_cntpct_stable();
+		write_sysreg(cval, cntp_cval_el0);
+	} else {
+		cval = evt + arch_counter_get_cntvct_stable();
+		write_sysreg(cval, cntv_cval_el0);
+	}
+
+	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
+}
+
+static __maybe_unused int erratum_set_next_event_virt(unsigned long evt,
+					    struct clock_event_device *clk)
+{
+	erratum_set_next_event_generic(ARCH_TIMER_VIRT_ACCESS, evt, clk);
+	return 0;
+}
+
+static __maybe_unused int erratum_set_next_event_phys(unsigned long evt,
+					    struct clock_event_device *clk)
+{
+	erratum_set_next_event_generic(ARCH_TIMER_PHYS_ACCESS, evt, clk);
+	return 0;
+}
+
+static const struct arch_timer_erratum_workaround ool_workarounds[] = {
+#ifdef CONFIG_FSL_ERRATUM_A008585
+	{
+		.match_type = ate_match_dt,
+		.id = "fsl,erratum-a008585",
+		.desc = "Freescale erratum a005858",
+		.read_cntpct_el0 = fsl_a008585_read_cntpct_el0,
+		.read_cntvct_el0 = fsl_a008585_read_cntvct_el0,
+		.set_next_event_phys = erratum_set_next_event_phys,
+		.set_next_event_virt = erratum_set_next_event_virt,
+	},
+#endif
+#ifdef CONFIG_HISILICON_ERRATUM_161010101
+	{
+		.match_type = ate_match_dt,
+		.id = "hisilicon,erratum-161010101",
+		.desc = "HiSilicon erratum 161010101",
+		.read_cntpct_el0 = hisi_161010101_read_cntpct_el0,
+		.read_cntvct_el0 = hisi_161010101_read_cntvct_el0,
+		.set_next_event_phys = erratum_set_next_event_phys,
+		.set_next_event_virt = erratum_set_next_event_virt,
+	},
+	{
+		.match_type = ate_match_acpi_oem_info,
+		.id = hisi_161010101_oem_info,
+		.desc = "HiSilicon erratum 161010101",
+		.read_cntpct_el0 = hisi_161010101_read_cntpct_el0,
+		.read_cntvct_el0 = hisi_161010101_read_cntvct_el0,
+		.set_next_event_phys = erratum_set_next_event_phys,
+		.set_next_event_virt = erratum_set_next_event_virt,
+	},
+#endif
+#ifdef CONFIG_ARM64_ERRATUM_858921
+	{
+		.match_type = ate_match_local_cap_id,
+		.id = (void *)ARM64_WORKAROUND_858921,
+		.desc = "ARM erratum 858921",
+		.read_cntpct_el0 = arm64_858921_read_cntpct_el0,
+		.read_cntvct_el0 = arm64_858921_read_cntvct_el0,
+		.set_next_event_phys = erratum_set_next_event_phys,
+		.set_next_event_virt = erratum_set_next_event_virt,
+	},
+#endif
+#ifdef CONFIG_SUN50I_ERRATUM_UNKNOWN1
+	{
+		.match_type = ate_match_dt,
+		.id = "allwinner,erratum-unknown1",
+		.desc = "Allwinner erratum UNKNOWN1",
+		.read_cntpct_el0 = sun50i_a64_read_cntpct_el0,
+		.read_cntvct_el0 = sun50i_a64_read_cntvct_el0,
+		.set_next_event_phys = erratum_set_next_event_phys,
+		.set_next_event_virt = erratum_set_next_event_virt,
+	},
+#endif
+#ifdef CONFIG_ARM64_ERRATUM_1418040
+	{
+		.match_type = ate_match_local_cap_id,
+		.id = (void *)ARM64_WORKAROUND_1418040,
+		.desc = "ARM erratum 1418040",
+		.disable_compat_vdso = true,
+	},
+#endif
+};
+
+typedef bool (*ate_match_fn_t)(const struct arch_timer_erratum_workaround *,
+			       const void *);
+
+static
+bool arch_timer_check_dt_erratum(const struct arch_timer_erratum_workaround *wa,
+				 const void *arg)
+{
+	const struct device_node *np = arg;
+
+	return of_property_read_bool(np, wa->id);
+}
+
+static
+bool arch_timer_check_local_cap_erratum(const struct arch_timer_erratum_workaround *wa,
+					const void *arg)
+{
+	return this_cpu_has_cap((uintptr_t)wa->id);
+}
+
+
+static
+bool arch_timer_check_acpi_oem_erratum(const struct arch_timer_erratum_workaround *wa,
+				       const void *arg)
+{
+	static const struct ate_acpi_oem_info empty_oem_info = {};
+	const struct ate_acpi_oem_info *info = wa->id;
+	const struct acpi_table_header *table = arg;
+
+	/* Iterate over the ACPI OEM info array, looking for a match */
+	while (memcmp(info, &empty_oem_info, sizeof(*info))) {
+		if (!memcmp(info->oem_id, table->oem_id, ACPI_OEM_ID_SIZE) &&
+		    !memcmp(info->oem_table_id, table->oem_table_id, ACPI_OEM_TABLE_ID_SIZE) &&
+		    info->oem_revision == table->oem_revision)
+			return true;
+
+		info++;
+	}
+
+	return false;
+}
+
+static const struct arch_timer_erratum_workaround *
+arch_timer_iterate_errata(enum arch_timer_erratum_match_type type,
+			  ate_match_fn_t match_fn,
+			  void *arg)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ool_workarounds); i++) {
+		if (ool_workarounds[i].match_type != type)
+			continue;
+
+		if (match_fn(&ool_workarounds[i], arg))
+			return &ool_workarounds[i];
+	}
+
+	return NULL;
+}
+
+static
+void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa,
+				  bool local)
+{
+	int i;
+
+	if (local) {
+		__this_cpu_write(timer_unstable_counter_workaround, wa);
+	} else {
+		for_each_possible_cpu(i)
+			per_cpu(timer_unstable_counter_workaround, i) = wa;
+	}
+
+	if (wa->read_cntvct_el0 || wa->read_cntpct_el0)
+		atomic_set(&timer_unstable_counter_workaround_in_use, 1);
+
+	/*
+	 * Don't use the vdso fastpath if errata require using the
+	 * out-of-line counter accessor. We may change our mind pretty
+	 * late in the game (with a per-CPU erratum, for example), so
+	 * change both the default value and the vdso itself.
+	 */
+	if (wa->read_cntvct_el0) {
+		clocksource_counter.vdso_clock_mode = VDSO_CLOCKMODE_NONE;
+		vdso_default = VDSO_CLOCKMODE_NONE;
+	} else if (wa->disable_compat_vdso && vdso_default != VDSO_CLOCKMODE_NONE) {
+		vdso_default = VDSO_CLOCKMODE_ARCHTIMER_NOCOMPAT;
+		clocksource_counter.vdso_clock_mode = vdso_default;
+	}
+}
+
+static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type type,
+					    void *arg)
+{
+	const struct arch_timer_erratum_workaround *wa, *__wa;
+	ate_match_fn_t match_fn = NULL;
+	bool local = false;
+
+	switch (type) {
+	case ate_match_dt:
+		match_fn = arch_timer_check_dt_erratum;
+		break;
+	case ate_match_local_cap_id:
+		match_fn = arch_timer_check_local_cap_erratum;
+		local = true;
+		break;
+	case ate_match_acpi_oem_info:
+		match_fn = arch_timer_check_acpi_oem_erratum;
+		break;
+	default:
+		WARN_ON(1);
+		return;
+	}
+
+	wa = arch_timer_iterate_errata(type, match_fn, arg);
+	if (!wa)
+		return;
+
+	__wa = __this_cpu_read(timer_unstable_counter_workaround);
+	if (__wa && wa != __wa)
+		pr_warn("Can't enable workaround for %s (clashes with %s\n)",
+			wa->desc, __wa->desc);
+
+	if (__wa)
+		return;
+
+	arch_timer_enable_workaround(wa, local);
+	pr_info("Enabling %s workaround for %s\n",
+		local ? "local" : "global", wa->desc);
+}
+
+static bool arch_timer_this_cpu_has_cntvct_wa(void)
+{
+	return has_erratum_handler(read_cntvct_el0);
+}
+
+static bool arch_timer_counter_has_wa(void)
+{
+	return atomic_read(&timer_unstable_counter_workaround_in_use);
+}
+#else
+#define arch_timer_check_ool_workaround(t,a)		do { } while(0)
+#define arch_timer_this_cpu_has_cntvct_wa()		({false;})
+#define arch_timer_counter_has_wa()			({false;})
+#endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */
+
+static __always_inline irqreturn_t timer_handler(const int access,
+					struct clock_event_device *evt)
+{
+	unsigned long ctrl;
+
+	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, evt);
+	if (ctrl & ARCH_TIMER_CTRL_IT_STAT) {
+		ctrl |= ARCH_TIMER_CTRL_IT_MASK;
+		arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, evt);
+		evt->event_handler(evt);
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
+}
+
+static irqreturn_t arch_timer_handler_virt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = dev_id;
+
+	return timer_handler(ARCH_TIMER_VIRT_ACCESS, evt);
+}
+
+static irqreturn_t arch_timer_handler_phys(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = dev_id;
+
+	return timer_handler(ARCH_TIMER_PHYS_ACCESS, evt);
+}
+
+static irqreturn_t arch_timer_handler_phys_mem(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = dev_id;
+
+	return timer_handler(ARCH_TIMER_MEM_PHYS_ACCESS, evt);
+}
+
+static irqreturn_t arch_timer_handler_virt_mem(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = dev_id;
+
+	return timer_handler(ARCH_TIMER_MEM_VIRT_ACCESS, evt);
+}
+
+static __always_inline int timer_shutdown(const int access,
+					  struct clock_event_device *clk)
+{
+	unsigned long ctrl;
+
+	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
+	ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
+	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
+
+	return 0;
+}
+
+static int arch_timer_shutdown_virt(struct clock_event_device *clk)
+{
+	return timer_shutdown(ARCH_TIMER_VIRT_ACCESS, clk);
+}
+
+static int arch_timer_shutdown_phys(struct clock_event_device *clk)
+{
+	return timer_shutdown(ARCH_TIMER_PHYS_ACCESS, clk);
+}
+
+static int arch_timer_shutdown_virt_mem(struct clock_event_device *clk)
+{
+	return timer_shutdown(ARCH_TIMER_MEM_VIRT_ACCESS, clk);
+}
+
+static int arch_timer_shutdown_phys_mem(struct clock_event_device *clk)
+{
+	return timer_shutdown(ARCH_TIMER_MEM_PHYS_ACCESS, clk);
+}
+
+static __always_inline void set_next_event(const int access, unsigned long evt,
+					   struct clock_event_device *clk)
+{
+	unsigned long ctrl;
+	u64 cnt;
+
+	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
+	ctrl |= ARCH_TIMER_CTRL_ENABLE;
+	ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
+
+	if (access == ARCH_TIMER_PHYS_ACCESS)
+		cnt = __arch_counter_get_cntpct();
+	else
+		cnt = __arch_counter_get_cntvct();
+
+	arch_timer_reg_write(access, ARCH_TIMER_REG_CVAL, evt + cnt, clk);
+	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
+}
+
+static int arch_timer_set_next_event_virt(unsigned long evt,
+					  struct clock_event_device *clk)
+{
+	set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk);
+	return 0;
+}
+
+static int arch_timer_set_next_event_phys(unsigned long evt,
+					  struct clock_event_device *clk)
+{
+	set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk);
+	return 0;
+}
+
+static u64 arch_counter_get_cnt_mem(struct arch_timer *t, int offset_lo)
+{
+	u32 cnt_lo, cnt_hi, tmp_hi;
+
+	do {
+		cnt_hi = readl_relaxed(t->base + offset_lo + 4);
+		cnt_lo = readl_relaxed(t->base + offset_lo);
+		tmp_hi = readl_relaxed(t->base + offset_lo + 4);
+	} while (cnt_hi != tmp_hi);
+
+	return ((u64) cnt_hi << 32) | cnt_lo;
+}
+
+static __always_inline void set_next_event_mem(const int access, unsigned long evt,
+					   struct clock_event_device *clk)
+{
+	struct arch_timer *timer = to_arch_timer(clk);
+	unsigned long ctrl;
+	u64 cnt;
+
+	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
+
+	/* Timer must be disabled before programming CVAL */
+	if (ctrl & ARCH_TIMER_CTRL_ENABLE) {
+		ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
+		arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
+	}
+
+	ctrl |= ARCH_TIMER_CTRL_ENABLE;
+	ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
+
+	if (access ==  ARCH_TIMER_MEM_VIRT_ACCESS)
+		cnt = arch_counter_get_cnt_mem(timer, CNTVCT_LO);
+	else
+		cnt = arch_counter_get_cnt_mem(timer, CNTPCT_LO);
+
+	arch_timer_reg_write(access, ARCH_TIMER_REG_CVAL, evt + cnt, clk);
+	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
+}
+
+static int arch_timer_set_next_event_virt_mem(unsigned long evt,
+					      struct clock_event_device *clk)
+{
+	set_next_event_mem(ARCH_TIMER_MEM_VIRT_ACCESS, evt, clk);
+	return 0;
+}
+
+static int arch_timer_set_next_event_phys_mem(unsigned long evt,
+					      struct clock_event_device *clk)
+{
+	set_next_event_mem(ARCH_TIMER_MEM_PHYS_ACCESS, evt, clk);
+	return 0;
+}
+
+static u64 __arch_timer_check_delta(void)
+{
+#ifdef CONFIG_ARM64
+	const struct midr_range broken_cval_midrs[] = {
+		/*
+		 * XGene-1 implements CVAL in terms of TVAL, meaning
+		 * that the maximum timer range is 32bit. Shame on them.
+		 *
+		 * Note that TVAL is signed, thus has only 31 of its
+		 * 32 bits to express magnitude.
+		 */
+		MIDR_REV_RANGE(MIDR_CPU_MODEL(ARM_CPU_IMP_APM,
+					      APM_CPU_PART_XGENE),
+			       APM_CPU_VAR_POTENZA, 0x0, 0xf),
+		{},
+	};
+
+	if (is_midr_in_range_list(read_cpuid_id(), broken_cval_midrs)) {
+		pr_warn_once("Broken CNTx_CVAL_EL1, using 31 bit TVAL instead.\n");
+		return CLOCKSOURCE_MASK(31);
+	}
+#endif
+	return CLOCKSOURCE_MASK(arch_counter_get_width());
+}
+
+static void __arch_timer_setup(unsigned type,
+			       struct clock_event_device *clk)
+{
+	u64 max_delta;
+
+	clk->features = CLOCK_EVT_FEAT_ONESHOT;
+
+	if (type == ARCH_TIMER_TYPE_CP15) {
+		typeof(clk->set_next_event) sne;
+
+		arch_timer_check_ool_workaround(ate_match_local_cap_id, NULL);
+
+		if (arch_timer_c3stop)
+			clk->features |= CLOCK_EVT_FEAT_C3STOP;
+		clk->name = "arch_sys_timer";
+		clk->rating = 450;
+		clk->cpumask = cpumask_of(smp_processor_id());
+		clk->irq = arch_timer_ppi[arch_timer_uses_ppi];
+		switch (arch_timer_uses_ppi) {
+		case ARCH_TIMER_VIRT_PPI:
+			clk->set_state_shutdown = arch_timer_shutdown_virt;
+			clk->set_state_oneshot_stopped = arch_timer_shutdown_virt;
+			sne = erratum_handler(set_next_event_virt);
+			break;
+		case ARCH_TIMER_PHYS_SECURE_PPI:
+		case ARCH_TIMER_PHYS_NONSECURE_PPI:
+		case ARCH_TIMER_HYP_PPI:
+			clk->set_state_shutdown = arch_timer_shutdown_phys;
+			clk->set_state_oneshot_stopped = arch_timer_shutdown_phys;
+			sne = erratum_handler(set_next_event_phys);
+			break;
+		default:
+			BUG();
+		}
+
+		clk->set_next_event = sne;
+		max_delta = __arch_timer_check_delta();
+	} else {
+		clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
+		clk->name = "arch_mem_timer";
+		clk->rating = 400;
+		clk->cpumask = cpu_possible_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;
+		}
+
+		max_delta = CLOCKSOURCE_MASK(56);
+	}
+
+	clk->set_state_shutdown(clk);
+
+	clockevents_config_and_register(clk, arch_timer_rate, 0xf, max_delta);
+}
+
+static void arch_timer_evtstrm_enable(unsigned int divider)
+{
+	u32 cntkctl = arch_timer_get_cntkctl();
+
+#ifdef CONFIG_ARM64
+	/* ECV is likely to require a large divider. Use the EVNTIS flag. */
+	if (cpus_have_const_cap(ARM64_HAS_ECV) && divider > 15) {
+		cntkctl |= ARCH_TIMER_EVT_INTERVAL_SCALE;
+		divider -= 8;
+	}
+#endif
+
+	divider = min(divider, 15U);
+	cntkctl &= ~ARCH_TIMER_EVT_TRIGGER_MASK;
+	/* Set the divider and enable virtual event stream */
+	cntkctl |= (divider << ARCH_TIMER_EVT_TRIGGER_SHIFT)
+			| ARCH_TIMER_VIRT_EVT_EN;
+	arch_timer_set_cntkctl(cntkctl);
+	arch_timer_set_evtstrm_feature();
+	cpumask_set_cpu(smp_processor_id(), &evtstrm_available);
+}
+
+static void arch_timer_configure_evtstream(void)
+{
+	int evt_stream_div, lsb;
+
+	/*
+	 * As the event stream can at most be generated at half the frequency
+	 * of the counter, use half the frequency when computing the divider.
+	 */
+	evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ / 2;
+
+	/*
+	 * Find the closest power of two to the divisor. If the adjacent bit
+	 * of lsb (last set bit, starts from 0) is set, then we use (lsb + 1).
+	 */
+	lsb = fls(evt_stream_div) - 1;
+	if (lsb > 0 && (evt_stream_div & BIT(lsb - 1)))
+		lsb++;
+
+	/* enable event stream */
+	arch_timer_evtstrm_enable(max(0, lsb));
+}
+
+static void arch_counter_set_user_access(void)
+{
+	u32 cntkctl = arch_timer_get_cntkctl();
+
+	/* Disable user access to the timers and both counters */
+	/* Also disable virtual event stream */
+	cntkctl &= ~(ARCH_TIMER_USR_PT_ACCESS_EN
+			| ARCH_TIMER_USR_VT_ACCESS_EN
+		        | ARCH_TIMER_USR_VCT_ACCESS_EN
+			| ARCH_TIMER_VIRT_EVT_EN
+			| ARCH_TIMER_USR_PCT_ACCESS_EN);
+
+	/*
+	 * Enable user access to the virtual counter if it doesn't
+	 * need to be workaround. The vdso may have been already
+	 * disabled though.
+	 */
+	if (arch_timer_this_cpu_has_cntvct_wa())
+		pr_info("CPU%d: Trapping CNTVCT access\n", smp_processor_id());
+	else
+		cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN;
+
+	arch_timer_set_cntkctl(cntkctl);
+}
+
+static bool arch_timer_has_nonsecure_ppi(void)
+{
+	return (arch_timer_uses_ppi == ARCH_TIMER_PHYS_SECURE_PPI &&
+		arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI]);
+}
+
+static u32 check_ppi_trigger(int irq)
+{
+	u32 flags = irq_get_trigger_type(irq);
+
+	if (flags != IRQF_TRIGGER_HIGH && flags != IRQF_TRIGGER_LOW) {
+		pr_warn("WARNING: Invalid trigger for IRQ%d, assuming level low\n", irq);
+		pr_warn("WARNING: Please fix your firmware\n");
+		flags = IRQF_TRIGGER_LOW;
+	}
+
+	return flags;
+}
+
+static int arch_timer_starting_cpu(unsigned int cpu)
+{
+	struct clock_event_device *clk = this_cpu_ptr(arch_timer_evt);
+	u32 flags;
+
+	__arch_timer_setup(ARCH_TIMER_TYPE_CP15, clk);
+
+	flags = check_ppi_trigger(arch_timer_ppi[arch_timer_uses_ppi]);
+	enable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], flags);
+
+	if (arch_timer_has_nonsecure_ppi()) {
+		flags = check_ppi_trigger(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI]);
+		enable_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI],
+				  flags);
+	}
+
+	arch_counter_set_user_access();
+	if (evtstrm_enable)
+		arch_timer_configure_evtstream();
+
+	return 0;
+}
+
+static int validate_timer_rate(void)
+{
+	if (!arch_timer_rate)
+		return -EINVAL;
+
+	/* Arch timer frequency < 1MHz can cause trouble */
+	WARN_ON(arch_timer_rate < 1000000);
+
+	return 0;
+}
+
+/*
+ * For historical reasons, when probing with DT we use whichever (non-zero)
+ * rate was probed first, and don't verify that others match. If the first node
+ * probed has a clock-frequency property, this overrides the HW register.
+ */
+static void __init arch_timer_of_configure_rate(u32 rate, struct device_node *np)
+{
+	/* Who has more than one independent system counter? */
+	if (arch_timer_rate)
+		return;
+
+	if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate))
+		arch_timer_rate = rate;
+
+	/* Check the timer frequency. */
+	if (validate_timer_rate())
+		pr_warn("frequency not available\n");
+}
+
+static void __init arch_timer_banner(unsigned type)
+{
+	pr_info("%s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n",
+		type & ARCH_TIMER_TYPE_CP15 ? "cp15" : "",
+		type == (ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM) ?
+			" and " : "",
+		type & ARCH_TIMER_TYPE_MEM ? "mmio" : "",
+		(unsigned long)arch_timer_rate / 1000000,
+		(unsigned long)(arch_timer_rate / 10000) % 100,
+		type & ARCH_TIMER_TYPE_CP15 ?
+			(arch_timer_uses_ppi == ARCH_TIMER_VIRT_PPI) ? "virt" : "phys" :
+			"",
+		type == (ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM) ? "/" : "",
+		type & ARCH_TIMER_TYPE_MEM ?
+			arch_timer_mem_use_virtual ? "virt" : "phys" :
+			"");
+}
+
+u32 arch_timer_get_rate(void)
+{
+	return arch_timer_rate;
+}
+
+bool arch_timer_evtstrm_available(void)
+{
+	/*
+	 * We might get called from a preemptible context. This is fine
+	 * because availability of the event stream should be always the same
+	 * for a preemptible context and context where we might resume a task.
+	 */
+	return cpumask_test_cpu(raw_smp_processor_id(), &evtstrm_available);
+}
+
+static u64 arch_counter_get_cntvct_mem(void)
+{
+	return arch_counter_get_cnt_mem(arch_timer_mem, CNTVCT_LO);
+}
+
+static struct arch_timer_kvm_info arch_timer_kvm_info;
+
+struct arch_timer_kvm_info *arch_timer_get_kvm_info(void)
+{
+	return &arch_timer_kvm_info;
+}
+
+static void __init arch_counter_register(unsigned type)
+{
+	u64 start_count;
+	int width;
+
+	/* Register the CP15 based counter if we have one */
+	if (type & ARCH_TIMER_TYPE_CP15) {
+		u64 (*rd)(void);
+
+		if ((IS_ENABLED(CONFIG_ARM64) && !is_hyp_mode_available()) ||
+		    arch_timer_uses_ppi == ARCH_TIMER_VIRT_PPI) {
+			if (arch_timer_counter_has_wa())
+				rd = arch_counter_get_cntvct_stable;
+			else
+				rd = arch_counter_get_cntvct;
+		} else {
+			if (arch_timer_counter_has_wa())
+				rd = arch_counter_get_cntpct_stable;
+			else
+				rd = arch_counter_get_cntpct;
+		}
+
+		arch_timer_read_counter = rd;
+		clocksource_counter.vdso_clock_mode = vdso_default;
+	} else {
+		arch_timer_read_counter = arch_counter_get_cntvct_mem;
+	}
+
+	width = arch_counter_get_width();
+	clocksource_counter.mask = CLOCKSOURCE_MASK(width);
+	cyclecounter.mask = CLOCKSOURCE_MASK(width);
+
+	if (!arch_counter_suspend_stop)
+		clocksource_counter.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP;
+	start_count = arch_timer_read_counter();
+	clocksource_register_hz(&clocksource_counter, arch_timer_rate);
+	cyclecounter.mult = clocksource_counter.mult;
+	cyclecounter.shift = clocksource_counter.shift;
+	timecounter_init(&arch_timer_kvm_info.timecounter,
+			 &cyclecounter, start_count);
+
+	sched_clock_register(arch_timer_read_counter, width, arch_timer_rate);
+}
+
+static void arch_timer_stop(struct clock_event_device *clk)
+{
+	pr_debug("disable IRQ%d cpu #%d\n", clk->irq, smp_processor_id());
+
+	disable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi]);
+	if (arch_timer_has_nonsecure_ppi())
+		disable_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI]);
+
+	clk->set_state_shutdown(clk);
+}
+
+static int arch_timer_dying_cpu(unsigned int cpu)
+{
+	struct clock_event_device *clk = this_cpu_ptr(arch_timer_evt);
+
+	cpumask_clear_cpu(smp_processor_id(), &evtstrm_available);
+
+	arch_timer_stop(clk);
+	return 0;
+}
+
+#ifdef CONFIG_CPU_PM
+static DEFINE_PER_CPU(unsigned long, saved_cntkctl);
+static int arch_timer_cpu_pm_notify(struct notifier_block *self,
+				    unsigned long action, void *hcpu)
+{
+	if (action == CPU_PM_ENTER) {
+		__this_cpu_write(saved_cntkctl, arch_timer_get_cntkctl());
+
+		cpumask_clear_cpu(smp_processor_id(), &evtstrm_available);
+	} else if (action == CPU_PM_ENTER_FAILED || action == CPU_PM_EXIT) {
+		arch_timer_set_cntkctl(__this_cpu_read(saved_cntkctl));
+
+		if (arch_timer_have_evtstrm_feature())
+			cpumask_set_cpu(smp_processor_id(), &evtstrm_available);
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block arch_timer_cpu_pm_notifier = {
+	.notifier_call = arch_timer_cpu_pm_notify,
+};
+
+static int __init arch_timer_cpu_pm_init(void)
+{
+	return cpu_pm_register_notifier(&arch_timer_cpu_pm_notifier);
+}
+
+static void __init arch_timer_cpu_pm_deinit(void)
+{
+	WARN_ON(cpu_pm_unregister_notifier(&arch_timer_cpu_pm_notifier));
+}
+
+#else
+static int __init arch_timer_cpu_pm_init(void)
+{
+	return 0;
+}
+
+static void __init arch_timer_cpu_pm_deinit(void)
+{
+}
+#endif
+
+static int __init arch_timer_register(void)
+{
+	int err;
+	int ppi;
+
+	arch_timer_evt = alloc_percpu(struct clock_event_device);
+	if (!arch_timer_evt) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	ppi = arch_timer_ppi[arch_timer_uses_ppi];
+	switch (arch_timer_uses_ppi) {
+	case ARCH_TIMER_VIRT_PPI:
+		err = request_percpu_irq(ppi, arch_timer_handler_virt,
+					 "arch_timer", arch_timer_evt);
+		break;
+	case ARCH_TIMER_PHYS_SECURE_PPI:
+	case ARCH_TIMER_PHYS_NONSECURE_PPI:
+		err = request_percpu_irq(ppi, arch_timer_handler_phys,
+					 "arch_timer", arch_timer_evt);
+		if (!err && arch_timer_has_nonsecure_ppi()) {
+			ppi = arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI];
+			err = request_percpu_irq(ppi, arch_timer_handler_phys,
+						 "arch_timer", arch_timer_evt);
+			if (err)
+				free_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_SECURE_PPI],
+						arch_timer_evt);
+		}
+		break;
+	case ARCH_TIMER_HYP_PPI:
+		err = request_percpu_irq(ppi, arch_timer_handler_phys,
+					 "arch_timer", arch_timer_evt);
+		break;
+	default:
+		BUG();
+	}
+
+	if (err) {
+		pr_err("can't register interrupt %d (%d)\n", ppi, err);
+		goto out_free;
+	}
+
+	err = arch_timer_cpu_pm_init();
+	if (err)
+		goto out_unreg_notify;
+
+	/* Register and immediately configure the timer on the boot CPU */
+	err = cpuhp_setup_state(CPUHP_AP_ARM_ARCH_TIMER_STARTING,
+				"clockevents/arm/arch_timer:starting",
+				arch_timer_starting_cpu, arch_timer_dying_cpu);
+	if (err)
+		goto out_unreg_cpupm;
+	return 0;
+
+out_unreg_cpupm:
+	arch_timer_cpu_pm_deinit();
+
+out_unreg_notify:
+	free_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], arch_timer_evt);
+	if (arch_timer_has_nonsecure_ppi())
+		free_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI],
+				arch_timer_evt);
+
+out_free:
+	free_percpu(arch_timer_evt);
+out:
+	return err;
+}
+
+static int __init arch_timer_mem_register(void __iomem *base, unsigned int irq)
+{
+	int ret;
+	irq_handler_t func;
+
+	arch_timer_mem = kzalloc(sizeof(*arch_timer_mem), GFP_KERNEL);
+	if (!arch_timer_mem)
+		return -ENOMEM;
+
+	arch_timer_mem->base = base;
+	arch_timer_mem->evt.irq = irq;
+	__arch_timer_setup(ARCH_TIMER_TYPE_MEM, &arch_timer_mem->evt);
+
+	if (arch_timer_mem_use_virtual)
+		func = arch_timer_handler_virt_mem;
+	else
+		func = arch_timer_handler_phys_mem;
+
+	ret = request_irq(irq, func, IRQF_TIMER, "arch_mem_timer", &arch_timer_mem->evt);
+	if (ret) {
+		pr_err("Failed to request mem timer irq\n");
+		kfree(arch_timer_mem);
+		arch_timer_mem = NULL;
+	}
+
+	return ret;
+}
+
+static const struct of_device_id arch_timer_of_match[] __initconst = {
+	{ .compatible   = "arm,armv7-timer",    },
+	{ .compatible   = "arm,armv8-timer",    },
+	{},
+};
+
+static const struct of_device_id arch_timer_mem_of_match[] __initconst = {
+	{ .compatible   = "arm,armv7-timer-mem", },
+	{},
+};
+
+static bool __init arch_timer_needs_of_probing(void)
+{
+	struct device_node *dn;
+	bool needs_probing = false;
+	unsigned int mask = ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM;
+
+	/* We have two timers, and both device-tree nodes are probed. */
+	if ((arch_timers_present & mask) == mask)
+		return false;
+
+	/*
+	 * Only one type of timer is probed,
+	 * check if we have another type of timer node in device-tree.
+	 */
+	if (arch_timers_present & ARCH_TIMER_TYPE_CP15)
+		dn = of_find_matching_node(NULL, arch_timer_mem_of_match);
+	else
+		dn = of_find_matching_node(NULL, arch_timer_of_match);
+
+	if (dn && of_device_is_available(dn))
+		needs_probing = true;
+
+	of_node_put(dn);
+
+	return needs_probing;
+}
+
+static int __init arch_timer_common_init(void)
+{
+	arch_timer_banner(arch_timers_present);
+	arch_counter_register(arch_timers_present);
+	return arch_timer_arch_init();
+}
+
+/**
+ * arch_timer_select_ppi() - Select suitable PPI for the current system.
+ *
+ * If HYP mode is available, we know that the physical timer
+ * has been configured to be accessible from PL1. Use it, so
+ * that a guest can use the virtual timer instead.
+ *
+ * On ARMv8.1 with VH extensions, the kernel runs in HYP. VHE
+ * accesses to CNTP_*_EL1 registers are silently redirected to
+ * their CNTHP_*_EL2 counterparts, and use a different PPI
+ * number.
+ *
+ * If no interrupt provided for virtual timer, we'll have to
+ * stick to the physical timer. It'd better be accessible...
+ * For arm64 we never use the secure interrupt.
+ *
+ * Return: a suitable PPI type for the current system.
+ */
+static enum arch_timer_ppi_nr __init arch_timer_select_ppi(void)
+{
+	if (is_kernel_in_hyp_mode())
+		return ARCH_TIMER_HYP_PPI;
+
+	if (!is_hyp_mode_available() && arch_timer_ppi[ARCH_TIMER_VIRT_PPI])
+		return ARCH_TIMER_VIRT_PPI;
+
+	if (IS_ENABLED(CONFIG_ARM64))
+		return ARCH_TIMER_PHYS_NONSECURE_PPI;
+
+	return ARCH_TIMER_PHYS_SECURE_PPI;
+}
+
+static void __init arch_timer_populate_kvm_info(void)
+{
+	arch_timer_kvm_info.virtual_irq = arch_timer_ppi[ARCH_TIMER_VIRT_PPI];
+	if (is_kernel_in_hyp_mode())
+		arch_timer_kvm_info.physical_irq = arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI];
+}
+
+static int __init arch_timer_of_init(struct device_node *np)
+{
+	int i, irq, ret;
+	u32 rate;
+	bool has_names;
+
+	if (arch_timers_present & ARCH_TIMER_TYPE_CP15) {
+		pr_warn("multiple nodes in dt, skipping\n");
+		return 0;
+	}
+
+	arch_timers_present |= ARCH_TIMER_TYPE_CP15;
+
+	has_names = of_property_read_bool(np, "interrupt-names");
+
+	for (i = ARCH_TIMER_PHYS_SECURE_PPI; i < ARCH_TIMER_MAX_TIMER_PPI; i++) {
+		if (has_names)
+			irq = of_irq_get_byname(np, arch_timer_ppi_names[i]);
+		else
+			irq = of_irq_get(np, i);
+		if (irq > 0)
+			arch_timer_ppi[i] = irq;
+	}
+
+	arch_timer_populate_kvm_info();
+
+	rate = arch_timer_get_cntfrq();
+	arch_timer_of_configure_rate(rate, np);
+
+	arch_timer_c3stop = !of_property_read_bool(np, "always-on");
+
+	/* Check for globally applicable workarounds */
+	arch_timer_check_ool_workaround(ate_match_dt, np);
+
+	/*
+	 * If we cannot rely on firmware initializing the timer registers then
+	 * we should use the physical timers instead.
+	 */
+	if (IS_ENABLED(CONFIG_ARM) &&
+	    of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
+		arch_timer_uses_ppi = ARCH_TIMER_PHYS_SECURE_PPI;
+	else
+		arch_timer_uses_ppi = arch_timer_select_ppi();
+
+	if (!arch_timer_ppi[arch_timer_uses_ppi]) {
+		pr_err("No interrupt available, giving up\n");
+		return -EINVAL;
+	}
+
+	/* On some systems, the counter stops ticking when in suspend. */
+	arch_counter_suspend_stop = of_property_read_bool(np,
+							 "arm,no-tick-in-suspend");
+
+	ret = arch_timer_register();
+	if (ret)
+		return ret;
+
+	if (arch_timer_needs_of_probing())
+		return 0;
+
+	return arch_timer_common_init();
+}
+TIMER_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_of_init);
+TIMER_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_of_init);
+
+static u32 __init
+arch_timer_mem_frame_get_cntfrq(struct arch_timer_mem_frame *frame)
+{
+	void __iomem *base;
+	u32 rate;
+
+	base = ioremap(frame->cntbase, frame->size);
+	if (!base) {
+		pr_err("Unable to map frame @ %pa\n", &frame->cntbase);
+		return 0;
+	}
+
+	rate = readl_relaxed(base + CNTFRQ);
+
+	iounmap(base);
+
+	return rate;
+}
+
+static struct arch_timer_mem_frame * __init
+arch_timer_mem_find_best_frame(struct arch_timer_mem *timer_mem)
+{
+	struct arch_timer_mem_frame *frame, *best_frame = NULL;
+	void __iomem *cntctlbase;
+	u32 cnttidr;
+	int i;
+
+	cntctlbase = ioremap(timer_mem->cntctlbase, timer_mem->size);
+	if (!cntctlbase) {
+		pr_err("Can't map CNTCTLBase @ %pa\n",
+			&timer_mem->cntctlbase);
+		return NULL;
+	}
+
+	cnttidr = readl_relaxed(cntctlbase + CNTTIDR);
+
+	/*
+	 * Try to find a virtual capable frame. Otherwise fall back to a
+	 * physical capable frame.
+	 */
+	for (i = 0; i < ARCH_TIMER_MEM_MAX_FRAMES; i++) {
+		u32 cntacr = CNTACR_RFRQ | CNTACR_RWPT | CNTACR_RPCT |
+			     CNTACR_RWVT | CNTACR_RVOFF | CNTACR_RVCT;
+
+		frame = &timer_mem->frame[i];
+		if (!frame->valid)
+			continue;
+
+		/* Try enabling everything, and see what sticks */
+		writel_relaxed(cntacr, cntctlbase + CNTACR(i));
+		cntacr = readl_relaxed(cntctlbase + CNTACR(i));
+
+		if ((cnttidr & CNTTIDR_VIRT(i)) &&
+		    !(~cntacr & (CNTACR_RWVT | CNTACR_RVCT))) {
+			best_frame = frame;
+			arch_timer_mem_use_virtual = true;
+			break;
+		}
+
+		if (~cntacr & (CNTACR_RWPT | CNTACR_RPCT))
+			continue;
+
+		best_frame = frame;
+	}
+
+	iounmap(cntctlbase);
+
+	return best_frame;
+}
+
+static int __init
+arch_timer_mem_frame_register(struct arch_timer_mem_frame *frame)
+{
+	void __iomem *base;
+	int ret, irq = 0;
+
+	if (arch_timer_mem_use_virtual)
+		irq = frame->virt_irq;
+	else
+		irq = frame->phys_irq;
+
+	if (!irq) {
+		pr_err("Frame missing %s irq.\n",
+		       arch_timer_mem_use_virtual ? "virt" : "phys");
+		return -EINVAL;
+	}
+
+	if (!request_mem_region(frame->cntbase, frame->size,
+				"arch_mem_timer"))
+		return -EBUSY;
+
+	base = ioremap(frame->cntbase, frame->size);
+	if (!base) {
+		pr_err("Can't map frame's registers\n");
+		return -ENXIO;
+	}
+
+	ret = arch_timer_mem_register(base, irq);
+	if (ret) {
+		iounmap(base);
+		return ret;
+	}
+
+	arch_timers_present |= ARCH_TIMER_TYPE_MEM;
+
+	return 0;
+}
+
+static int __init arch_timer_mem_of_init(struct device_node *np)
+{
+	struct arch_timer_mem *timer_mem;
+	struct arch_timer_mem_frame *frame;
+	struct device_node *frame_node;
+	struct resource res;
+	int ret = -EINVAL;
+	u32 rate;
+
+	timer_mem = kzalloc(sizeof(*timer_mem), GFP_KERNEL);
+	if (!timer_mem)
+		return -ENOMEM;
+
+	if (of_address_to_resource(np, 0, &res))
+		goto out;
+	timer_mem->cntctlbase = res.start;
+	timer_mem->size = resource_size(&res);
+
+	for_each_available_child_of_node(np, frame_node) {
+		u32 n;
+		struct arch_timer_mem_frame *frame;
+
+		if (of_property_read_u32(frame_node, "frame-number", &n)) {
+			pr_err(FW_BUG "Missing frame-number.\n");
+			of_node_put(frame_node);
+			goto out;
+		}
+		if (n >= ARCH_TIMER_MEM_MAX_FRAMES) {
+			pr_err(FW_BUG "Wrong frame-number, only 0-%u are permitted.\n",
+			       ARCH_TIMER_MEM_MAX_FRAMES - 1);
+			of_node_put(frame_node);
+			goto out;
+		}
+		frame = &timer_mem->frame[n];
+
+		if (frame->valid) {
+			pr_err(FW_BUG "Duplicated frame-number.\n");
+			of_node_put(frame_node);
+			goto out;
+		}
+
+		if (of_address_to_resource(frame_node, 0, &res)) {
+			of_node_put(frame_node);
+			goto out;
+		}
+		frame->cntbase = res.start;
+		frame->size = resource_size(&res);
+
+		frame->virt_irq = irq_of_parse_and_map(frame_node,
+						       ARCH_TIMER_VIRT_SPI);
+		frame->phys_irq = irq_of_parse_and_map(frame_node,
+						       ARCH_TIMER_PHYS_SPI);
+
+		frame->valid = true;
+	}
+
+	frame = arch_timer_mem_find_best_frame(timer_mem);
+	if (!frame) {
+		pr_err("Unable to find a suitable frame in timer @ %pa\n",
+			&timer_mem->cntctlbase);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	rate = arch_timer_mem_frame_get_cntfrq(frame);
+	arch_timer_of_configure_rate(rate, np);
+
+	ret = arch_timer_mem_frame_register(frame);
+	if (!ret && !arch_timer_needs_of_probing())
+		ret = arch_timer_common_init();
+out:
+	kfree(timer_mem);
+	return ret;
+}
+TIMER_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
+		       arch_timer_mem_of_init);
+
+#ifdef CONFIG_ACPI_GTDT
+static int __init
+arch_timer_mem_verify_cntfrq(struct arch_timer_mem *timer_mem)
+{
+	struct arch_timer_mem_frame *frame;
+	u32 rate;
+	int i;
+
+	for (i = 0; i < ARCH_TIMER_MEM_MAX_FRAMES; i++) {
+		frame = &timer_mem->frame[i];
+
+		if (!frame->valid)
+			continue;
+
+		rate = arch_timer_mem_frame_get_cntfrq(frame);
+		if (rate == arch_timer_rate)
+			continue;
+
+		pr_err(FW_BUG "CNTFRQ mismatch: frame @ %pa: (0x%08lx), CPU: (0x%08lx)\n",
+			&frame->cntbase,
+			(unsigned long)rate, (unsigned long)arch_timer_rate);
+
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int __init arch_timer_mem_acpi_init(int platform_timer_count)
+{
+	struct arch_timer_mem *timers, *timer;
+	struct arch_timer_mem_frame *frame, *best_frame = NULL;
+	int timer_count, i, ret = 0;
+
+	timers = kcalloc(platform_timer_count, sizeof(*timers),
+			    GFP_KERNEL);
+	if (!timers)
+		return -ENOMEM;
+
+	ret = acpi_arch_timer_mem_init(timers, &timer_count);
+	if (ret || !timer_count)
+		goto out;
+
+	/*
+	 * While unlikely, it's theoretically possible that none of the frames
+	 * in a timer expose the combination of feature we want.
+	 */
+	for (i = 0; i < timer_count; i++) {
+		timer = &timers[i];
+
+		frame = arch_timer_mem_find_best_frame(timer);
+		if (!best_frame)
+			best_frame = frame;
+
+		ret = arch_timer_mem_verify_cntfrq(timer);
+		if (ret) {
+			pr_err("Disabling MMIO timers due to CNTFRQ mismatch\n");
+			goto out;
+		}
+
+		if (!best_frame) /* implies !frame */
+			/*
+			 * Only complain about missing suitable frames if we
+			 * haven't already found one in a previous iteration.
+			 */
+			pr_err("Unable to find a suitable frame in timer @ %pa\n",
+				&timer->cntctlbase);
+	}
+
+	if (best_frame)
+		ret = arch_timer_mem_frame_register(best_frame);
+out:
+	kfree(timers);
+	return ret;
+}
+
+/* Initialize per-processor generic timer and memory-mapped timer(if present) */
+static int __init arch_timer_acpi_init(struct acpi_table_header *table)
+{
+	int ret, platform_timer_count;
+
+	if (arch_timers_present & ARCH_TIMER_TYPE_CP15) {
+		pr_warn("already initialized, skipping\n");
+		return -EINVAL;
+	}
+
+	arch_timers_present |= ARCH_TIMER_TYPE_CP15;
+
+	ret = acpi_gtdt_init(table, &platform_timer_count);
+	if (ret)
+		return ret;
+
+	arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI] =
+		acpi_gtdt_map_ppi(ARCH_TIMER_PHYS_NONSECURE_PPI);
+
+	arch_timer_ppi[ARCH_TIMER_VIRT_PPI] =
+		acpi_gtdt_map_ppi(ARCH_TIMER_VIRT_PPI);
+
+	arch_timer_ppi[ARCH_TIMER_HYP_PPI] =
+		acpi_gtdt_map_ppi(ARCH_TIMER_HYP_PPI);
+
+	arch_timer_populate_kvm_info();
+
+	/*
+	 * When probing via ACPI, we have no mechanism to override the sysreg
+	 * CNTFRQ value. This *must* be correct.
+	 */
+	arch_timer_rate = arch_timer_get_cntfrq();
+	ret = validate_timer_rate();
+	if (ret) {
+		pr_err(FW_BUG "frequency not available.\n");
+		return ret;
+	}
+
+	arch_timer_uses_ppi = arch_timer_select_ppi();
+	if (!arch_timer_ppi[arch_timer_uses_ppi]) {
+		pr_err("No interrupt available, giving up\n");
+		return -EINVAL;
+	}
+
+	/* Always-on capability */
+	arch_timer_c3stop = acpi_gtdt_c3stop(arch_timer_uses_ppi);
+
+	/* Check for globally applicable workarounds */
+	arch_timer_check_ool_workaround(ate_match_acpi_oem_info, table);
+
+	ret = arch_timer_register();
+	if (ret)
+		return ret;
+
+	if (platform_timer_count &&
+	    arch_timer_mem_acpi_init(platform_timer_count))
+		pr_err("Failed to initialize memory-mapped timer.\n");
+
+	return arch_timer_common_init();
+}
+TIMER_ACPI_DECLARE(arch_timer, ACPI_SIG_GTDT, arch_timer_acpi_init);
+#endif
+
+int kvm_arch_ptp_get_crosststamp(u64 *cycle, struct timespec64 *ts,
+				 struct clocksource **cs)
+{
+	struct arm_smccc_res hvc_res;
+	u32 ptp_counter;
+	ktime_t ktime;
+
+	if (!IS_ENABLED(CONFIG_HAVE_ARM_SMCCC_DISCOVERY))
+		return -EOPNOTSUPP;
+
+	if (arch_timer_uses_ppi == ARCH_TIMER_VIRT_PPI)
+		ptp_counter = KVM_PTP_VIRT_COUNTER;
+	else
+		ptp_counter = KVM_PTP_PHYS_COUNTER;
+
+	arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID,
+			     ptp_counter, &hvc_res);
+
+	if ((int)(hvc_res.a0) < 0)
+		return -EOPNOTSUPP;
+
+	ktime = (u64)hvc_res.a0 << 32 | hvc_res.a1;
+	*ts = ktime_to_timespec64(ktime);
+	if (cycle)
+		*cycle = (u64)hvc_res.a2 << 32 | hvc_res.a3;
+	if (cs)
+		*cs = &clocksource_counter;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_arch_ptp_get_crosststamp);