Merge tag 'arch-timer-gtdt' of git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux into timers/core

Pull arch timer GTDT support from Mark Rutland - arch_timer cleanups and refactoring - new common GTDT parser - GTDT-based MMIO arch_timer support - GTDT-based SBSA watchdog support Fix up a trivial pr_err() conflict.
2026-05-02 18:17:50 -04:00 · 2017-04-20 08:28:34 +02:00
parent 821596a50a ca9ae5ec4e
commit 26e42a0204
7 changed files with 855 additions and 223 deletions
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -33,6 +33,9 @@

 #include <clocksource/arm_arch_timer.h>

+#undef pr_fmt
+#define pr_fmt(fmt) "arch_timer: " fmt
+
 #define CNTTIDR		0x08
 #define CNTTIDR_VIRT(n)	(BIT(1) << ((n) * 4))

@@ -52,8 +55,6 @@
 #define CNTV_TVAL	0x38
 #define CNTV_CTL	0x3c

-#define ARCH_CP15_TIMER	BIT(0)
-#define ARCH_MEM_TIMER	BIT(1)
 static unsigned arch_timers_present __initdata;

 static void __iomem *arch_counter_base;
@@ -66,20 +67,11 @@ struct arch_timer {
 #define to_arch_timer(e) container_of(e, struct arch_timer, evt)

 static u32 arch_timer_rate;
-
-enum ppi_nr {
-	PHYS_SECURE_PPI,
-	PHYS_NONSECURE_PPI,
-	VIRT_PPI,
-	HYP_PPI,
-	MAX_TIMER_PPI
-};
-
-static int arch_timer_ppi[MAX_TIMER_PPI];
+static int arch_timer_ppi[ARCH_TIMER_MAX_TIMER_PPI];

 static struct clock_event_device __percpu *arch_timer_evt;

-static enum ppi_nr arch_timer_uses_ppi = VIRT_PPI;
+static enum arch_timer_ppi_nr arch_timer_uses_ppi = ARCH_TIMER_VIRT_PPI;
 static bool arch_timer_c3stop;
 static bool arch_timer_mem_use_virtual;
 static bool arch_counter_suspend_stop;
@@ -683,7 +675,7 @@ static void __arch_timer_setup(unsigned type,
 {
 	clk->features = CLOCK_EVT_FEAT_ONESHOT;

-	if (type == ARCH_CP15_TIMER) {
+	if (type == ARCH_TIMER_TYPE_CP15) {
 		if (arch_timer_c3stop)
 			clk->features |= CLOCK_EVT_FEAT_C3STOP;
 		clk->name = "arch_sys_timer";
@@ -691,14 +683,14 @@ static void __arch_timer_setup(unsigned type,
 		clk->cpumask = cpumask_of(smp_processor_id());
 		clk->irq = arch_timer_ppi[arch_timer_uses_ppi];
 		switch (arch_timer_uses_ppi) {
-		case VIRT_PPI:
+		case ARCH_TIMER_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;
 			break;
-		case PHYS_SECURE_PPI:
-		case PHYS_NONSECURE_PPI:
-		case HYP_PPI:
+		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;
 			clk->set_next_event = arch_timer_set_next_event_phys;
@@ -786,8 +778,8 @@ static void arch_counter_set_user_access(void)

 static bool arch_timer_has_nonsecure_ppi(void)
 {
-	return (arch_timer_uses_ppi == PHYS_SECURE_PPI &&
-		arch_timer_ppi[PHYS_NONSECURE_PPI]);
+	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)
@@ -808,14 +800,15 @@ 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_CP15_TIMER, clk);
+	__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[PHYS_NONSECURE_PPI]);
-		enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], flags);
+		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();
@@ -825,43 +818,39 @@ static int arch_timer_starting_cpu(unsigned int cpu)
 	return 0;
 }

-static void
-arch_timer_detect_rate(void __iomem *cntbase, struct device_node *np)
+/*
+ * 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 arch_timer_of_configure_rate(u32 rate, struct device_node *np)
 {
 	/* Who has more than one independent system counter? */
 	if (arch_timer_rate)
 		return;

-	/*
-	 * Try to determine the frequency from the device tree or CNTFRQ,
-	 * if ACPI is enabled, get the frequency from CNTFRQ ONLY.
-	 */
-	if (!acpi_disabled ||
-	    of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) {
-		if (cntbase)
-			arch_timer_rate = readl_relaxed(cntbase + CNTFRQ);
-		else
-			arch_timer_rate = arch_timer_get_cntfrq();
-	}
+	if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate))
+		arch_timer_rate = rate;

 	/* Check the timer frequency. */
 	if (arch_timer_rate == 0)
-		pr_warn("Architected timer frequency not available\n");
+		pr_warn("frequency not available\n");
 }

 static void arch_timer_banner(unsigned type)
 {
-	pr_info("Architected %s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n",
-		     type & ARCH_CP15_TIMER ? "cp15" : "",
-		     type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ?  " and " : "",
-		     type & ARCH_MEM_TIMER ? "mmio" : "",
-		     (unsigned long)arch_timer_rate / 1000000,
-		     (unsigned long)(arch_timer_rate / 10000) % 100,
-		     type & ARCH_CP15_TIMER ?
-		     (arch_timer_uses_ppi == VIRT_PPI) ? "virt" : "phys" :
+	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_CP15_TIMER | ARCH_MEM_TIMER) ?  "/" : "",
-		     type & ARCH_MEM_TIMER ?
+		type == (ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM) ? "/" : "",
+		type & ARCH_TIMER_TYPE_MEM ?
 			arch_timer_mem_use_virtual ? "virt" : "phys" :
 			"");
 }
@@ -896,8 +885,9 @@ static void __init arch_counter_register(unsigned type)
 	u64 start_count;

 	/* Register the CP15 based counter if we have one */
-	if (type & ARCH_CP15_TIMER) {
-		if (IS_ENABLED(CONFIG_ARM64) || arch_timer_uses_ppi == VIRT_PPI)
+	if (type & ARCH_TIMER_TYPE_CP15) {
+		if (IS_ENABLED(CONFIG_ARM64) ||
+		    arch_timer_uses_ppi == ARCH_TIMER_VIRT_PPI)
 			arch_timer_read_counter = arch_counter_get_cntvct;
 		else
 			arch_timer_read_counter = arch_counter_get_cntpct;
@@ -922,12 +912,11 @@ static void __init arch_counter_register(unsigned type)

 static void arch_timer_stop(struct clock_event_device *clk)
 {
-	pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n",
-		 clk->irq, smp_processor_id());
+	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[PHYS_NONSECURE_PPI]);
+		disable_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI]);

 	clk->set_state_shutdown(clk);
 }
@@ -990,24 +979,24 @@ static int __init arch_timer_register(void)

 	ppi = arch_timer_ppi[arch_timer_uses_ppi];
 	switch (arch_timer_uses_ppi) {
-	case VIRT_PPI:
+	case ARCH_TIMER_VIRT_PPI:
 		err = request_percpu_irq(ppi, arch_timer_handler_virt,
 					 "arch_timer", arch_timer_evt);
 		break;
-	case PHYS_SECURE_PPI:
-	case PHYS_NONSECURE_PPI:
+	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_ppi[PHYS_NONSECURE_PPI]) {
-			ppi = arch_timer_ppi[PHYS_NONSECURE_PPI];
+		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[PHYS_SECURE_PPI],
+				free_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_SECURE_PPI],
 						arch_timer_evt);
 		}
 		break;
-	case HYP_PPI:
+	case ARCH_TIMER_HYP_PPI:
 		err = request_percpu_irq(ppi, arch_timer_handler_phys,
 					 "arch_timer", arch_timer_evt);
 		break;
@@ -1016,8 +1005,7 @@ static int __init arch_timer_register(void)
 	}

 	if (err) {
-		pr_err("arch_timer: can't register interrupt %d (%d)\n",
-		       ppi, err);
+		pr_err("can't register interrupt %d (%d)\n", ppi, err);
 		goto out_free;
 	}

@@ -1040,7 +1028,7 @@ out_unreg_cpupm:
 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[PHYS_NONSECURE_PPI],
+		free_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI],
 				arch_timer_evt);

 out_free:
@@ -1061,7 +1049,7 @@ static int __init arch_timer_mem_register(void __iomem *base, unsigned int irq)

 	t->base = base;
 	t->evt.irq = irq;
-	__arch_timer_setup(ARCH_MEM_TIMER, &t->evt);
+	__arch_timer_setup(ARCH_TIMER_TYPE_MEM, &t->evt);

 	if (arch_timer_mem_use_virtual)
 		func = arch_timer_handler_virt_mem;
@@ -1070,7 +1058,7 @@ static int __init arch_timer_mem_register(void __iomem *base, unsigned int irq)

 	ret = request_irq(irq, func, IRQF_TIMER, "arch_mem_timer", &t->evt);
 	if (ret) {
-		pr_err("arch_timer: Failed to request mem timer irq\n");
+		pr_err("Failed to request mem timer irq\n");
 		kfree(t);
 	}

@@ -1088,15 +1076,28 @@ static const struct of_device_id arch_timer_mem_of_match[] __initconst = {
 	{},
 };

-static bool __init
-arch_timer_needs_probing(int type, const struct of_device_id *matches)
+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;

-	dn = of_find_matching_node(NULL, matches);
-	if (dn && of_device_is_available(dn) && !(arch_timers_present & type))
+	/* 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;
@@ -1104,82 +1105,61 @@ arch_timer_needs_probing(int type, const struct of_device_id *matches)

 static int __init arch_timer_common_init(void)
 {
-	unsigned mask = ARCH_CP15_TIMER | ARCH_MEM_TIMER;
-
-	/* Wait until both nodes are probed if we have two timers */
-	if ((arch_timers_present & mask) != mask) {
-		if (arch_timer_needs_probing(ARCH_MEM_TIMER, arch_timer_mem_of_match))
-			return 0;
-		if (arch_timer_needs_probing(ARCH_CP15_TIMER, arch_timer_of_match))
-			return 0;
-	}
-
 	arch_timer_banner(arch_timers_present);
 	arch_counter_register(arch_timers_present);
 	return arch_timer_arch_init();
 }

-static int __init arch_timer_init(void)
+/**
+ * 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)
 {
-	int ret;
-	/*
-	 * 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.
-	 *
-	 * If no interrupt provided for virtual timer, we'll have to
-	 * stick to the physical timer. It'd better be accessible...
-	 *
-	 * 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 (is_hyp_mode_available() || !arch_timer_ppi[VIRT_PPI]) {
-		bool has_ppi;
+	if (is_kernel_in_hyp_mode())
+		return ARCH_TIMER_HYP_PPI;

-		if (is_kernel_in_hyp_mode()) {
-			arch_timer_uses_ppi = HYP_PPI;
-			has_ppi = !!arch_timer_ppi[HYP_PPI];
-		} else {
-			arch_timer_uses_ppi = PHYS_SECURE_PPI;
-			has_ppi = (!!arch_timer_ppi[PHYS_SECURE_PPI] ||
-				   !!arch_timer_ppi[PHYS_NONSECURE_PPI]);
-		}
+	if (!is_hyp_mode_available() && arch_timer_ppi[ARCH_TIMER_VIRT_PPI])
+		return ARCH_TIMER_VIRT_PPI;

-		if (!has_ppi) {
-			pr_warn("arch_timer: No interrupt available, giving up\n");
-			return -EINVAL;
-		}
-	}
+	if (IS_ENABLED(CONFIG_ARM64))
+		return ARCH_TIMER_PHYS_NONSECURE_PPI;

-	ret = arch_timer_register();
-	if (ret)
-		return ret;
-
-	ret = arch_timer_common_init();
-	if (ret)
-		return ret;
-
-	arch_timer_kvm_info.virtual_irq = arch_timer_ppi[VIRT_PPI];
-	
-	return 0;
+	return ARCH_TIMER_PHYS_SECURE_PPI;
 }

 static int __init arch_timer_of_init(struct device_node *np)
 {
-	int i;
+	int i, ret;
+	u32 rate;

-	if (arch_timers_present & ARCH_CP15_TIMER) {
-		pr_warn("arch_timer: multiple nodes in dt, skipping\n");
+	if (arch_timers_present & ARCH_TIMER_TYPE_CP15) {
+		pr_warn("multiple nodes in dt, skipping\n");
 		return 0;
 	}

-	arch_timers_present |= ARCH_CP15_TIMER;
-	for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
+	arch_timers_present |= ARCH_TIMER_TYPE_CP15;
+	for (i = ARCH_TIMER_PHYS_SECURE_PPI; i < ARCH_TIMER_MAX_TIMER_PPI; i++)
 		arch_timer_ppi[i] = irq_of_parse_and_map(np, i);

-	arch_timer_detect_rate(NULL, np);
+	arch_timer_kvm_info.virtual_irq = arch_timer_ppi[ARCH_TIMER_VIRT_PPI];
+
+	rate = arch_timer_get_cntfrq();
+	arch_timer_of_configure_rate(rate, np);

 	arch_timer_c3stop = !of_property_read_bool(np, "always-on");

@@ -1192,29 +1172,63 @@ static int __init arch_timer_of_init(struct device_node *np)
 	 */
 	if (IS_ENABLED(CONFIG_ARM) &&
 	    of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
-		arch_timer_uses_ppi = PHYS_SECURE_PPI;
+		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");

-	return arch_timer_init();
+	ret = arch_timer_register();
+	if (ret)
+		return ret;
+
+	if (arch_timer_needs_of_probing())
+		return 0;
+
+	return arch_timer_common_init();
 }
 CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_of_init);
 CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_of_init);

-static int __init arch_timer_mem_init(struct device_node *np)
+static u32 __init
+arch_timer_mem_frame_get_cntfrq(struct arch_timer_mem_frame *frame)
 {
-	struct device_node *frame, *best_frame = NULL;
-	void __iomem *cntctlbase, *base;
-	unsigned int irq, ret = -EINVAL;
-	u32 cnttidr;
+	void __iomem *base;
+	u32 rate;

-	arch_timers_present |= ARCH_MEM_TIMER;
-	cntctlbase = of_iomap(np, 0);
+	base = ioremap(frame->cntbase, frame->size);
+	if (!base) {
+		pr_err("Unable to map frame @ %pa\n", &frame->cntbase);
+		return 0;
+	}
+
+	rate = readl_relaxed(frame + CNTFRQ);
+
+	iounmap(frame);
+
+	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("arch_timer: Can't find CNTCTLBase\n");
-		return -ENXIO;
+		pr_err("Can't map CNTCTLBase @ %pa\n",
+			&timer_mem->cntctlbase);
+		return NULL;
 	}

 	cnttidr = readl_relaxed(cntctlbase + CNTTIDR);
@@ -1223,25 +1237,20 @@ static int __init arch_timer_mem_init(struct device_node *np)
 	 * Try to find a virtual capable frame. Otherwise fall back to a
 	 * physical capable frame.
 	 */
-	for_each_available_child_of_node(np, frame) {
-		int n;
-		u32 cntacr;
+	for (i = 0; i < ARCH_TIMER_MEM_MAX_FRAMES; i++) {
+		u32 cntacr = CNTACR_RFRQ | CNTACR_RWPT | CNTACR_RPCT |
+			     CNTACR_RWVT | CNTACR_RVOFF | CNTACR_RVCT;

-		if (of_property_read_u32(frame, "frame-number", &n)) {
-			pr_err("arch_timer: Missing frame-number\n");
-			of_node_put(frame);
-			goto out;
-		}
+		frame = &timer_mem->frame[i];
+		if (!frame->valid)
+			continue;

 		/* 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));
+		writel_relaxed(cntacr, cntctlbase + CNTACR(i));
+		cntacr = readl_relaxed(cntctlbase + CNTACR(i));

-		if ((cnttidr & CNTTIDR_VIRT(n)) &&
+		if ((cnttidr & CNTTIDR_VIRT(i)) &&
 		    !(~cntacr & (CNTACR_RWVT | CNTACR_RVCT))) {
-			of_node_put(best_frame);
 			best_frame = frame;
 			arch_timer_mem_use_virtual = true;
 			break;
@@ -1250,102 +1259,262 @@ static int __init arch_timer_mem_init(struct device_node *np)
 		if (~cntacr & (CNTACR_RWPT | CNTACR_RPCT))
 			continue;

-		of_node_put(best_frame);
-		best_frame = of_node_get(frame);
+		best_frame = frame;
 	}

-	ret= -ENXIO;
-	base = arch_counter_base = of_io_request_and_map(best_frame, 0,
-							 "arch_mem_timer");
-	if (IS_ERR(base)) {
-		pr_err("arch_timer: Can't map frame's registers\n");
-		goto out;
-	}
+	iounmap(cntctlbase);
+
+	if (!best_frame)
+		pr_err("Unable to find a suitable frame in timer @ %pa\n",
+			&timer_mem->cntctlbase);
+
+	return 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 = irq_of_parse_and_map(best_frame, 1);
+		irq = frame->virt_irq;
 	else
-		irq = irq_of_parse_and_map(best_frame, 0);
+		irq = frame->phys_irq;

-	ret = -EINVAL;
 	if (!irq) {
-		pr_err("arch_timer: Frame missing %s irq\n",
+		pr_err("Frame missing %s irq.\n",
 		       arch_timer_mem_use_virtual ? "virt" : "phys");
-		goto out;
-	}
-
-	arch_timer_detect_rate(base, np);
-	ret = arch_timer_mem_register(base, irq);
-	if (ret)
-		goto out;
-
-	return arch_timer_common_init();
-out:
-	iounmap(cntctlbase);
-	of_node_put(best_frame);
-	return ret;
-}
-CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
-		       arch_timer_mem_init);
-
-#ifdef CONFIG_ACPI
-static int __init map_generic_timer_interrupt(u32 interrupt, u32 flags)
-{
-	int trigger, polarity;
-
-	if (!interrupt)
-		return 0;
-
-	trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
-			: ACPI_LEVEL_SENSITIVE;
-
-	polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
-			: ACPI_ACTIVE_HIGH;
-
-	return acpi_register_gsi(NULL, interrupt, trigger, polarity);
-}
-
-/* Initialize per-processor generic timer */
-static int __init arch_timer_acpi_init(struct acpi_table_header *table)
-{
-	struct acpi_table_gtdt *gtdt;
-
-	if (arch_timers_present & ARCH_CP15_TIMER) {
-		pr_warn("arch_timer: already initialized, skipping\n");
 		return -EINVAL;
 	}

-	gtdt = container_of(table, struct acpi_table_gtdt, header);
+	if (!request_mem_region(frame->cntbase, frame->size,
+				"arch_mem_timer"))
+		return -EBUSY;

-	arch_timers_present |= ARCH_CP15_TIMER;
+	base = ioremap(frame->cntbase, frame->size);
+	if (!base) {
+		pr_err("Can't map frame's registers\n");
+		return -ENXIO;
+	}

-	arch_timer_ppi[PHYS_SECURE_PPI] =
-		map_generic_timer_interrupt(gtdt->secure_el1_interrupt,
-		gtdt->secure_el1_flags);
+	ret = arch_timer_mem_register(base, irq);
+	if (ret) {
+		iounmap(base);
+		return ret;
+	}

-	arch_timer_ppi[PHYS_NONSECURE_PPI] =
-		map_generic_timer_interrupt(gtdt->non_secure_el1_interrupt,
-		gtdt->non_secure_el1_flags);
+	arch_counter_base = base;
+	arch_timers_present |= ARCH_TIMER_TYPE_MEM;

-	arch_timer_ppi[VIRT_PPI] =
-		map_generic_timer_interrupt(gtdt->virtual_timer_interrupt,
-		gtdt->virtual_timer_flags);
+	return 0;
+}

-	arch_timer_ppi[HYP_PPI] =
-		map_generic_timer_interrupt(gtdt->non_secure_el2_interrupt,
-		gtdt->non_secure_el2_flags);
+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;

-	/* Get the frequency from CNTFRQ */
-	arch_timer_detect_rate(NULL, NULL);
+	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) {
+		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;
+}
+CLOCKSOURCE_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;
+	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;
+
+	for (i = 0; i < timer_count; i++) {
+		ret = arch_timer_mem_verify_cntfrq(&timers[i]);
+		if (ret) {
+			pr_err("Disabling MMIO timers due to CNTFRQ mismatch\n");
+			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 = i; i < timer_count; i++) {
+		timer = &timers[i];
+
+		frame = arch_timer_mem_find_best_frame(timer);
+		if (frame)
+			break;
+	}
+
+	if (frame)
+		ret = arch_timer_mem_frame_register(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) {
+		pr_err("Failed to init GTDT table.\n");
+		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_kvm_info.virtual_irq = arch_timer_ppi[ARCH_TIMER_VIRT_PPI];
+
+	/*
+	 * 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();
+	if (!arch_timer_rate) {
+		pr_err(FW_BUG "frequency not available.\n");
+		return -EINVAL;
+	}
+
+	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 = !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);
+	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);

-	arch_timer_init();
-	return 0;
+	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();
 }
 CLOCKSOURCE_ACPI_DECLARE(arch_timer, ACPI_SIG_GTDT, arch_timer_acpi_init);
 #endif