Adding upstream version 5.10.209.upstream/5.10.209upstream

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

1 files changed, 853 insertions, 0 deletions

diff --git a/drivers/clocksource/timer-ti-dm-systimer.c b/drivers/clocksource/timer-ti-dm-systimer.c
new file mode 100644
index 000000000..632523c12
--- /dev/null
+++ b/drivers/clocksource/timer-ti-dm-systimer.c
@@ -0,0 +1,853 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include <linux/clk.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/cpuhotplug.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/sched_clock.h>
+
+#include <linux/clk/clk-conf.h>
+
+#include <clocksource/timer-ti-dm.h>
+#include <dt-bindings/bus/ti-sysc.h>
+
+/* For type1, set SYSC_OMAP2_CLOCKACTIVITY for fck off on idle, l4 clock on */
+#define DMTIMER_TYPE1_ENABLE	((1 << 9) | (SYSC_IDLE_SMART << 3) | \
+				 SYSC_OMAP2_ENAWAKEUP | SYSC_OMAP2_AUTOIDLE)
+#define DMTIMER_TYPE1_DISABLE	(SYSC_OMAP2_SOFTRESET | SYSC_OMAP2_AUTOIDLE)
+#define DMTIMER_TYPE2_ENABLE	(SYSC_IDLE_SMART_WKUP << 2)
+#define DMTIMER_RESET_WAIT	100000
+
+#define DMTIMER_INST_DONT_CARE	~0U
+
+static int counter_32k;
+static u32 clocksource;
+static u32 clockevent;
+
+/*
+ * Subset of the timer registers we use. Note that the register offsets
+ * depend on the timer revision detected.
+ */
+struct dmtimer_systimer {
+	void __iomem *base;
+	u8 sysc;
+	u8 irq_stat;
+	u8 irq_ena;
+	u8 pend;
+	u8 load;
+	u8 counter;
+	u8 ctrl;
+	u8 wakeup;
+	u8 ifctrl;
+	struct clk *fck;
+	struct clk *ick;
+	unsigned long rate;
+};
+
+struct dmtimer_clockevent {
+	struct clock_event_device dev;
+	struct dmtimer_systimer t;
+	u32 period;
+};
+
+struct dmtimer_clocksource {
+	struct clocksource dev;
+	struct dmtimer_systimer t;
+	unsigned int loadval;
+};
+
+/* Assumes v1 ip if bits [31:16] are zero */
+static bool dmtimer_systimer_revision1(struct dmtimer_systimer *t)
+{
+	u32 tidr = readl_relaxed(t->base);
+
+	return !(tidr >> 16);
+}
+
+static void dmtimer_systimer_enable(struct dmtimer_systimer *t)
+{
+	u32 val;
+
+	if (dmtimer_systimer_revision1(t))
+		val = DMTIMER_TYPE1_ENABLE;
+	else
+		val = DMTIMER_TYPE2_ENABLE;
+
+	writel_relaxed(val, t->base + t->sysc);
+}
+
+static void dmtimer_systimer_disable(struct dmtimer_systimer *t)
+{
+	if (!dmtimer_systimer_revision1(t))
+		return;
+
+	writel_relaxed(DMTIMER_TYPE1_DISABLE, t->base + t->sysc);
+}
+
+static int __init dmtimer_systimer_type1_reset(struct dmtimer_systimer *t)
+{
+	void __iomem *syss = t->base + OMAP_TIMER_V1_SYS_STAT_OFFSET;
+	int ret;
+	u32 l;
+
+	dmtimer_systimer_enable(t);
+	writel_relaxed(BIT(1) | BIT(2), t->base + t->ifctrl);
+	ret = readl_poll_timeout_atomic(syss, l, l & BIT(0), 100,
+					DMTIMER_RESET_WAIT);
+
+	return ret;
+}
+
+/* Note we must use io_base instead of func_base for type2 OCP regs */
+static int __init dmtimer_systimer_type2_reset(struct dmtimer_systimer *t)
+{
+	void __iomem *sysc = t->base + t->sysc;
+	u32 l;
+
+	dmtimer_systimer_enable(t);
+	l = readl_relaxed(sysc);
+	l |= BIT(0);
+	writel_relaxed(l, sysc);
+
+	return readl_poll_timeout_atomic(sysc, l, !(l & BIT(0)), 100,
+					 DMTIMER_RESET_WAIT);
+}
+
+static int __init dmtimer_systimer_reset(struct dmtimer_systimer *t)
+{
+	int ret;
+
+	if (dmtimer_systimer_revision1(t))
+		ret = dmtimer_systimer_type1_reset(t);
+	else
+		ret = dmtimer_systimer_type2_reset(t);
+	if (ret < 0) {
+		pr_err("%s failed with %i\n", __func__, ret);
+
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id counter_match_table[] = {
+	{ .compatible = "ti,omap-counter32k" },
+	{ /* Sentinel */ },
+};
+
+/*
+ * Check if the SoC als has a usable working 32 KiHz counter. The 32 KiHz
+ * counter is handled by timer-ti-32k, but we need to detect it as it
+ * affects the preferred dmtimer system timer configuration. There is
+ * typically no use for a dmtimer clocksource if the 32 KiHz counter is
+ * present, except on am437x as described below.
+ */
+static void __init dmtimer_systimer_check_counter32k(void)
+{
+	struct device_node *np;
+
+	if (counter_32k)
+		return;
+
+	np = of_find_matching_node(NULL, counter_match_table);
+	if (!np) {
+		counter_32k = -ENODEV;
+
+		return;
+	}
+
+	if (of_device_is_available(np))
+		counter_32k = 1;
+	else
+		counter_32k = -ENODEV;
+
+	of_node_put(np);
+}
+
+static const struct of_device_id dmtimer_match_table[] = {
+	{ .compatible = "ti,omap2420-timer", },
+	{ .compatible = "ti,omap3430-timer", },
+	{ .compatible = "ti,omap4430-timer", },
+	{ .compatible = "ti,omap5430-timer", },
+	{ .compatible = "ti,am335x-timer", },
+	{ .compatible = "ti,am335x-timer-1ms", },
+	{ .compatible = "ti,dm814-timer", },
+	{ .compatible = "ti,dm816-timer", },
+	{ /* Sentinel */ },
+};
+
+/*
+ * Checks that system timers are configured to not reset and idle during
+ * the generic timer-ti-dm device driver probe. And that the system timer
+ * source clocks are properly configured. Also, let's not hog any DSP and
+ * PWM capable timers unnecessarily as system timers.
+ */
+static bool __init dmtimer_is_preferred(struct device_node *np)
+{
+	if (!of_device_is_available(np))
+		return false;
+
+	if (!of_property_read_bool(np->parent,
+				   "ti,no-reset-on-init"))
+		return false;
+
+	if (!of_property_read_bool(np->parent, "ti,no-idle"))
+		return false;
+
+	/* Secure gptimer12 is always clocked with a fixed source */
+	if (!of_property_read_bool(np, "ti,timer-secure")) {
+		if (!of_property_read_bool(np, "assigned-clocks"))
+			return false;
+
+		if (!of_property_read_bool(np, "assigned-clock-parents"))
+			return false;
+	}
+
+	if (of_property_read_bool(np, "ti,timer-dsp"))
+		return false;
+
+	if (of_property_read_bool(np, "ti,timer-pwm"))
+		return false;
+
+	return true;
+}
+
+/*
+ * Finds the first available usable always-on timer, and assigns it to either
+ * clockevent or clocksource depending if the counter_32k is available on the
+ * SoC or not.
+ *
+ * Some omap3 boards with unreliable oscillator must not use the counter_32k
+ * or dmtimer1 with 32 KiHz source. Additionally, the boards with unreliable
+ * oscillator should really set counter_32k as disabled, and delete dmtimer1
+ * ti,always-on property, but let's not count on it. For these quirky cases,
+ * we prefer using the always-on secure dmtimer12 with the internal 32 KiHz
+ * clock as the clocksource, and any available dmtimer as clockevent.
+ *
+ * For am437x, we are using am335x style dmtimer clocksource. It is unclear
+ * if this quirk handling is really needed, but let's change it separately
+ * based on testing as it might cause side effects.
+ */
+static void __init dmtimer_systimer_assign_alwon(void)
+{
+	struct device_node *np;
+	u32 pa = 0;
+	bool quirk_unreliable_oscillator = false;
+
+	/* Quirk unreliable 32 KiHz oscillator with incomplete dts */
+	if (of_machine_is_compatible("ti,omap3-beagle-ab4")) {
+		quirk_unreliable_oscillator = true;
+		counter_32k = -ENODEV;
+	}
+
+	/* Quirk am437x using am335x style dmtimer clocksource */
+	if (of_machine_is_compatible("ti,am43"))
+		counter_32k = -ENODEV;
+
+	for_each_matching_node(np, dmtimer_match_table) {
+		if (!dmtimer_is_preferred(np))
+			continue;
+
+		if (of_property_read_bool(np, "ti,timer-alwon")) {
+			const __be32 *addr;
+
+			addr = of_get_address(np, 0, NULL, NULL);
+			pa = of_translate_address(np, addr);
+			if (pa) {
+				/* Quirky omap3 boards must use dmtimer12 */
+				if (quirk_unreliable_oscillator &&
+				    pa == 0x48318000)
+					continue;
+
+				of_node_put(np);
+				break;
+			}
+		}
+	}
+
+	/* Usually no need for dmtimer clocksource if we have counter32 */
+	if (counter_32k >= 0) {
+		clockevent = pa;
+		clocksource = 0;
+	} else {
+		clocksource = pa;
+		clockevent = DMTIMER_INST_DONT_CARE;
+	}
+}
+
+/* Finds the first usable dmtimer, used for the don't care case */
+static u32 __init dmtimer_systimer_find_first_available(void)
+{
+	struct device_node *np;
+	const __be32 *addr;
+	u32 pa = 0;
+
+	for_each_matching_node(np, dmtimer_match_table) {
+		if (!dmtimer_is_preferred(np))
+			continue;
+
+		addr = of_get_address(np, 0, NULL, NULL);
+		pa = of_translate_address(np, addr);
+		if (pa) {
+			if (pa == clocksource || pa == clockevent) {
+				pa = 0;
+				continue;
+			}
+
+			of_node_put(np);
+			break;
+		}
+	}
+
+	return pa;
+}
+
+/* Selects the best clocksource and clockevent to use */
+static void __init dmtimer_systimer_select_best(void)
+{
+	dmtimer_systimer_check_counter32k();
+	dmtimer_systimer_assign_alwon();
+
+	if (clockevent == DMTIMER_INST_DONT_CARE)
+		clockevent = dmtimer_systimer_find_first_available();
+
+	pr_debug("%s: counter_32k: %i clocksource: %08x clockevent: %08x\n",
+		 __func__, counter_32k, clocksource, clockevent);
+}
+
+/* Interface clocks are only available on some SoCs variants */
+static int __init dmtimer_systimer_init_clock(struct dmtimer_systimer *t,
+					      struct device_node *np,
+					      const char *name,
+					      unsigned long *rate)
+{
+	struct clk *clock;
+	unsigned long r;
+	bool is_ick = false;
+	int error;
+
+	is_ick = !strncmp(name, "ick", 3);
+
+	clock = of_clk_get_by_name(np, name);
+	if ((PTR_ERR(clock) == -EINVAL) && is_ick)
+		return 0;
+	else if (IS_ERR(clock))
+		return PTR_ERR(clock);
+
+	error = clk_prepare_enable(clock);
+	if (error)
+		return error;
+
+	r = clk_get_rate(clock);
+	if (!r) {
+		clk_disable_unprepare(clock);
+		return -ENODEV;
+	}
+
+	if (is_ick)
+		t->ick = clock;
+	else
+		t->fck = clock;
+
+	*rate = r;
+
+	return 0;
+}
+
+static int __init dmtimer_systimer_setup(struct device_node *np,
+					 struct dmtimer_systimer *t)
+{
+	unsigned long rate;
+	u8 regbase;
+	int error;
+
+	if (!of_device_is_compatible(np->parent, "ti,sysc"))
+		return -EINVAL;
+
+	t->base = of_iomap(np, 0);
+	if (!t->base)
+		return -ENXIO;
+
+	/*
+	 * Enable optional assigned-clock-parents configured at the timer
+	 * node level. For regular device drivers, this is done automatically
+	 * by bus related code such as platform_drv_probe().
+	 */
+	error = of_clk_set_defaults(np, false);
+	if (error < 0)
+		pr_err("%s: clock source init failed: %i\n", __func__, error);
+
+	/* For ti-sysc, we have timer clocks at the parent module level */
+	error = dmtimer_systimer_init_clock(t, np->parent, "fck", &rate);
+	if (error)
+		goto err_unmap;
+
+	t->rate = rate;
+
+	error = dmtimer_systimer_init_clock(t, np->parent, "ick", &rate);
+	if (error)
+		goto err_unmap;
+
+	if (dmtimer_systimer_revision1(t)) {
+		t->irq_stat = OMAP_TIMER_V1_STAT_OFFSET;
+		t->irq_ena = OMAP_TIMER_V1_INT_EN_OFFSET;
+		t->pend = _OMAP_TIMER_WRITE_PEND_OFFSET;
+		regbase = 0;
+	} else {
+		t->irq_stat = OMAP_TIMER_V2_IRQSTATUS;
+		t->irq_ena = OMAP_TIMER_V2_IRQENABLE_SET;
+		regbase = OMAP_TIMER_V2_FUNC_OFFSET;
+		t->pend = regbase + _OMAP_TIMER_WRITE_PEND_OFFSET;
+	}
+
+	t->sysc = OMAP_TIMER_OCP_CFG_OFFSET;
+	t->load = regbase + _OMAP_TIMER_LOAD_OFFSET;
+	t->counter = regbase + _OMAP_TIMER_COUNTER_OFFSET;
+	t->ctrl = regbase + _OMAP_TIMER_CTRL_OFFSET;
+	t->wakeup = regbase + _OMAP_TIMER_WAKEUP_EN_OFFSET;
+	t->ifctrl = regbase + _OMAP_TIMER_IF_CTRL_OFFSET;
+
+	dmtimer_systimer_reset(t);
+	dmtimer_systimer_enable(t);
+	pr_debug("dmtimer rev %08x sysc %08x\n", readl_relaxed(t->base),
+		 readl_relaxed(t->base + t->sysc));
+
+	return 0;
+
+err_unmap:
+	iounmap(t->base);
+
+	return error;
+}
+
+/* Clockevent */
+static struct dmtimer_clockevent *
+to_dmtimer_clockevent(struct clock_event_device *clockevent)
+{
+	return container_of(clockevent, struct dmtimer_clockevent, dev);
+}
+
+static irqreturn_t dmtimer_clockevent_interrupt(int irq, void *data)
+{
+	struct dmtimer_clockevent *clkevt = data;
+	struct dmtimer_systimer *t = &clkevt->t;
+
+	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_stat);
+	clkevt->dev.event_handler(&clkevt->dev);
+
+	return IRQ_HANDLED;
+}
+
+static int dmtimer_set_next_event(unsigned long cycles,
+				  struct clock_event_device *evt)
+{
+	struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
+	struct dmtimer_systimer *t = &clkevt->t;
+	void __iomem *pend = t->base + t->pend;
+
+	while (readl_relaxed(pend) & WP_TCRR)
+		cpu_relax();
+	writel_relaxed(0xffffffff - cycles, t->base + t->counter);
+
+	while (readl_relaxed(pend) & WP_TCLR)
+		cpu_relax();
+	writel_relaxed(OMAP_TIMER_CTRL_ST, t->base + t->ctrl);
+
+	return 0;
+}
+
+static int dmtimer_clockevent_shutdown(struct clock_event_device *evt)
+{
+	struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
+	struct dmtimer_systimer *t = &clkevt->t;
+	void __iomem *ctrl = t->base + t->ctrl;
+	u32 l;
+
+	l = readl_relaxed(ctrl);
+	if (l & OMAP_TIMER_CTRL_ST) {
+		l &= ~BIT(0);
+		writel_relaxed(l, ctrl);
+		/* Flush posted write */
+		l = readl_relaxed(ctrl);
+		/*  Wait for functional clock period x 3.5 */
+		udelay(3500000 / t->rate + 1);
+	}
+	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_stat);
+
+	return 0;
+}
+
+static int dmtimer_set_periodic(struct clock_event_device *evt)
+{
+	struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
+	struct dmtimer_systimer *t = &clkevt->t;
+	void __iomem *pend = t->base + t->pend;
+
+	dmtimer_clockevent_shutdown(evt);
+
+	/* Looks like we need to first set the load value separately */
+	while (readl_relaxed(pend) & WP_TLDR)
+		cpu_relax();
+	writel_relaxed(clkevt->period, t->base + t->load);
+
+	while (readl_relaxed(pend) & WP_TCRR)
+		cpu_relax();
+	writel_relaxed(clkevt->period, t->base + t->counter);
+
+	while (readl_relaxed(pend) & WP_TCLR)
+		cpu_relax();
+	writel_relaxed(OMAP_TIMER_CTRL_AR | OMAP_TIMER_CTRL_ST,
+		       t->base + t->ctrl);
+
+	return 0;
+}
+
+static void omap_clockevent_idle(struct clock_event_device *evt)
+{
+	struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
+	struct dmtimer_systimer *t = &clkevt->t;
+
+	dmtimer_systimer_disable(t);
+	clk_disable(t->fck);
+}
+
+static void omap_clockevent_unidle(struct clock_event_device *evt)
+{
+	struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
+	struct dmtimer_systimer *t = &clkevt->t;
+	int error;
+
+	error = clk_enable(t->fck);
+	if (error)
+		pr_err("could not enable timer fck on resume: %i\n", error);
+
+	dmtimer_systimer_enable(t);
+	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_ena);
+	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->wakeup);
+}
+
+static int __init dmtimer_clkevt_init_common(struct dmtimer_clockevent *clkevt,
+					     struct device_node *np,
+					     unsigned int features,
+					     const struct cpumask *cpumask,
+					     const char *name,
+					     int rating)
+{
+	struct clock_event_device *dev;
+	struct dmtimer_systimer *t;
+	int error;
+
+	t = &clkevt->t;
+	dev = &clkevt->dev;
+
+	/*
+	 * We mostly use cpuidle_coupled with ARM local timers for runtime,
+	 * so there's probably no use for CLOCK_EVT_FEAT_DYNIRQ here.
+	 */
+	dev->features = features;
+	dev->rating = rating;
+	dev->set_next_event = dmtimer_set_next_event;
+	dev->set_state_shutdown = dmtimer_clockevent_shutdown;
+	dev->set_state_periodic = dmtimer_set_periodic;
+	dev->set_state_oneshot = dmtimer_clockevent_shutdown;
+	dev->set_state_oneshot_stopped = dmtimer_clockevent_shutdown;
+	dev->tick_resume = dmtimer_clockevent_shutdown;
+	dev->cpumask = cpumask;
+
+	dev->irq = irq_of_parse_and_map(np, 0);
+	if (!dev->irq)
+		return -ENXIO;
+
+	error = dmtimer_systimer_setup(np, &clkevt->t);
+	if (error)
+		return error;
+
+	clkevt->period = 0xffffffff - DIV_ROUND_CLOSEST(t->rate, HZ);
+
+	/*
+	 * For clock-event timers we never read the timer counter and
+	 * so we are not impacted by errata i103 and i767. Therefore,
+	 * we can safely ignore this errata for clock-event timers.
+	 */
+	writel_relaxed(OMAP_TIMER_CTRL_POSTED, t->base + t->ifctrl);
+
+	error = request_irq(dev->irq, dmtimer_clockevent_interrupt,
+			    IRQF_TIMER, name, clkevt);
+	if (error)
+		goto err_out_unmap;
+
+	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_ena);
+	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->wakeup);
+
+	pr_info("TI gptimer %s: %s%lu Hz at %pOF\n",
+		name, of_find_property(np, "ti,timer-alwon", NULL) ?
+		"always-on " : "", t->rate, np->parent);
+
+	return 0;
+
+err_out_unmap:
+	iounmap(t->base);
+
+	return error;
+}
+
+static int __init dmtimer_clockevent_init(struct device_node *np)
+{
+	struct dmtimer_clockevent *clkevt;
+	int error;
+
+	clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL);
+	if (!clkevt)
+		return -ENOMEM;
+
+	error = dmtimer_clkevt_init_common(clkevt, np,
+					   CLOCK_EVT_FEAT_PERIODIC |
+					   CLOCK_EVT_FEAT_ONESHOT,
+					   cpu_possible_mask, "clockevent",
+					   300);
+	if (error)
+		goto err_out_free;
+
+	clockevents_config_and_register(&clkevt->dev, clkevt->t.rate,
+					3, /* Timer internal resync latency */
+					0xffffffff);
+
+	if (of_machine_is_compatible("ti,am33xx") ||
+	    of_machine_is_compatible("ti,am43")) {
+		clkevt->dev.suspend = omap_clockevent_idle;
+		clkevt->dev.resume = omap_clockevent_unidle;
+	}
+
+	return 0;
+
+err_out_free:
+	kfree(clkevt);
+
+	return error;
+}
+
+/* Dmtimer as percpu timer. See dra7 ARM architected timer wrap erratum i940 */
+static DEFINE_PER_CPU(struct dmtimer_clockevent, dmtimer_percpu_timer);
+
+static int __init dmtimer_percpu_timer_init(struct device_node *np, int cpu)
+{
+	struct dmtimer_clockevent *clkevt;
+	int error;
+
+	if (!cpu_possible(cpu))
+		return -EINVAL;
+
+	if (!of_property_read_bool(np->parent, "ti,no-reset-on-init") ||
+	    !of_property_read_bool(np->parent, "ti,no-idle"))
+		pr_warn("Incomplete dtb for percpu dmtimer %pOF\n", np->parent);
+
+	clkevt = per_cpu_ptr(&dmtimer_percpu_timer, cpu);
+
+	error = dmtimer_clkevt_init_common(clkevt, np, CLOCK_EVT_FEAT_ONESHOT,
+					   cpumask_of(cpu), "percpu-dmtimer",
+					   500);
+	if (error)
+		return error;
+
+	return 0;
+}
+
+/* See TRM for timer internal resynch latency */
+static int omap_dmtimer_starting_cpu(unsigned int cpu)
+{
+	struct dmtimer_clockevent *clkevt = per_cpu_ptr(&dmtimer_percpu_timer, cpu);
+	struct clock_event_device *dev = &clkevt->dev;
+	struct dmtimer_systimer *t = &clkevt->t;
+
+	clockevents_config_and_register(dev, t->rate, 3, ULONG_MAX);
+	irq_force_affinity(dev->irq, cpumask_of(cpu));
+
+	return 0;
+}
+
+static int __init dmtimer_percpu_timer_startup(void)
+{
+	struct dmtimer_clockevent *clkevt = per_cpu_ptr(&dmtimer_percpu_timer, 0);
+	struct dmtimer_systimer *t = &clkevt->t;
+
+	if (t->sysc) {
+		cpuhp_setup_state(CPUHP_AP_TI_GP_TIMER_STARTING,
+				  "clockevents/omap/gptimer:starting",
+				  omap_dmtimer_starting_cpu, NULL);
+	}
+
+	return 0;
+}
+subsys_initcall(dmtimer_percpu_timer_startup);
+
+static int __init dmtimer_percpu_quirk_init(struct device_node *np, u32 pa)
+{
+	struct device_node *arm_timer;
+
+	arm_timer = of_find_compatible_node(NULL, NULL, "arm,armv7-timer");
+	if (of_device_is_available(arm_timer)) {
+		pr_warn_once("ARM architected timer wrap issue i940 detected\n");
+		return 0;
+	}
+
+	if (pa == 0x4882c000)           /* dra7 dmtimer15 */
+		return dmtimer_percpu_timer_init(np, 0);
+	else if (pa == 0x4882e000)      /* dra7 dmtimer16 */
+		return dmtimer_percpu_timer_init(np, 1);
+
+	return 0;
+}
+
+/* Clocksource */
+static struct dmtimer_clocksource *
+to_dmtimer_clocksource(struct clocksource *cs)
+{
+	return container_of(cs, struct dmtimer_clocksource, dev);
+}
+
+static u64 dmtimer_clocksource_read_cycles(struct clocksource *cs)
+{
+	struct dmtimer_clocksource *clksrc = to_dmtimer_clocksource(cs);
+	struct dmtimer_systimer *t = &clksrc->t;
+
+	return (u64)readl_relaxed(t->base + t->counter);
+}
+
+static void __iomem *dmtimer_sched_clock_counter;
+
+static u64 notrace dmtimer_read_sched_clock(void)
+{
+	return readl_relaxed(dmtimer_sched_clock_counter);
+}
+
+static void dmtimer_clocksource_suspend(struct clocksource *cs)
+{
+	struct dmtimer_clocksource *clksrc = to_dmtimer_clocksource(cs);
+	struct dmtimer_systimer *t = &clksrc->t;
+
+	clksrc->loadval = readl_relaxed(t->base + t->counter);
+	dmtimer_systimer_disable(t);
+	clk_disable(t->fck);
+}
+
+static void dmtimer_clocksource_resume(struct clocksource *cs)
+{
+	struct dmtimer_clocksource *clksrc = to_dmtimer_clocksource(cs);
+	struct dmtimer_systimer *t = &clksrc->t;
+	int error;
+
+	error = clk_enable(t->fck);
+	if (error)
+		pr_err("could not enable timer fck on resume: %i\n", error);
+
+	dmtimer_systimer_enable(t);
+	writel_relaxed(clksrc->loadval, t->base + t->counter);
+	writel_relaxed(OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR,
+		       t->base + t->ctrl);
+}
+
+static int __init dmtimer_clocksource_init(struct device_node *np)
+{
+	struct dmtimer_clocksource *clksrc;
+	struct dmtimer_systimer *t;
+	struct clocksource *dev;
+	int error;
+
+	clksrc = kzalloc(sizeof(*clksrc), GFP_KERNEL);
+	if (!clksrc)
+		return -ENOMEM;
+
+	dev = &clksrc->dev;
+	t = &clksrc->t;
+
+	error = dmtimer_systimer_setup(np, t);
+	if (error)
+		goto err_out_free;
+
+	dev->name = "dmtimer";
+	dev->rating = 300;
+	dev->read = dmtimer_clocksource_read_cycles;
+	dev->mask = CLOCKSOURCE_MASK(32);
+	dev->flags = CLOCK_SOURCE_IS_CONTINUOUS;
+
+	/* Unlike for clockevent, legacy code sets suspend only for am4 */
+	if (of_machine_is_compatible("ti,am43")) {
+		dev->suspend = dmtimer_clocksource_suspend;
+		dev->resume = dmtimer_clocksource_resume;
+	}
+
+	writel_relaxed(0, t->base + t->counter);
+	writel_relaxed(OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR,
+		       t->base + t->ctrl);
+
+	pr_info("TI gptimer clocksource: %s%pOF\n",
+		of_find_property(np, "ti,timer-alwon", NULL) ?
+		"always-on " : "", np->parent);
+
+	if (!dmtimer_sched_clock_counter) {
+		dmtimer_sched_clock_counter = t->base + t->counter;
+		sched_clock_register(dmtimer_read_sched_clock, 32, t->rate);
+	}
+
+	if (clocksource_register_hz(dev, t->rate))
+		pr_err("Could not register clocksource %pOF\n", np);
+
+	return 0;
+
+err_out_free:
+	kfree(clksrc);
+
+	return -ENODEV;
+}
+
+/*
+ * To detect between a clocksource and clockevent, we assume the device tree
+ * has no interrupts configured for a clocksource timer.
+ */
+static int __init dmtimer_systimer_init(struct device_node *np)
+{
+	const __be32 *addr;
+	u32 pa;
+
+	/* One time init for the preferred timer configuration */
+	if (!clocksource && !clockevent)
+		dmtimer_systimer_select_best();
+
+	if (!clocksource && !clockevent) {
+		pr_err("%s: unable to detect system timers, update dtb?\n",
+		       __func__);
+
+		return -EINVAL;
+	}
+
+	addr = of_get_address(np, 0, NULL, NULL);
+	pa = of_translate_address(np, addr);
+	if (!pa)
+		return -EINVAL;
+
+	if (counter_32k <= 0 && clocksource == pa)
+		return dmtimer_clocksource_init(np);
+
+	if (clockevent == pa)
+		return dmtimer_clockevent_init(np);
+
+	if (of_machine_is_compatible("ti,dra7"))
+		return dmtimer_percpu_quirk_init(np, pa);
+
+	return 0;
+}
+
+TIMER_OF_DECLARE(systimer_omap2, "ti,omap2420-timer", dmtimer_systimer_init);
+TIMER_OF_DECLARE(systimer_omap3, "ti,omap3430-timer", dmtimer_systimer_init);
+TIMER_OF_DECLARE(systimer_omap4, "ti,omap4430-timer", dmtimer_systimer_init);
+TIMER_OF_DECLARE(systimer_omap5, "ti,omap5430-timer", dmtimer_systimer_init);
+TIMER_OF_DECLARE(systimer_am33x, "ti,am335x-timer", dmtimer_systimer_init);
+TIMER_OF_DECLARE(systimer_am3ms, "ti,am335x-timer-1ms", dmtimer_systimer_init);
+TIMER_OF_DECLARE(systimer_dm814, "ti,dm814-timer", dmtimer_systimer_init);
+TIMER_OF_DECLARE(systimer_dm816, "ti,dm816-timer", dmtimer_systimer_init);