Merge tag 'omap-for-v5.8/timer-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into arm/soc

System timer changes for omaps for v5.8 merge window

This series of changes finally gets the legacy omap dual-mode timer and
32k counter system timer updated to use drivers/clocksource and device
tree data. And we can now remove the unused legacy platform data.

These changes are based on an immutable clocksource branch set up by
Daniel Lezcano.

* tag 'omap-for-v5.8/timer-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
  bus: ti-sysc: Timers no longer need legacy quirk handling
  ARM: OMAP2+: Drop old timer code for dmtimer and 32k counter
  ARM: dts: Configure system timers for omap2
  ARM: dts: Configure system timers for ti81xx
  ARM: dts: Configure system timers for omap3
  ARM: dts: Configure system timers for omap5 and dra7
  ARM: dts: Configure system timers for omap4
  ARM: dts: Configure system timers for am437x
  ARM: dts: Configure system timers for am335x
  ARM: OMAP2+: Add omap_init_time_of()
  bus: ti-sysc: Ignore timer12 on secure omap3
  clk: ti: dm816: enable sysclk6_ck on init
  clocksource/drivers/timer-ti-dm: Fix warning for set but not used
  clocksource/drivers/timer-ti-dm: Add clockevent and clocksource support
  clocksource/drivers/timer-ti-32k: Add support for initializing directly

Link: https://lore.kernel.org/r/pull-1590169577-735045@atomide.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

5 files changed, 794 insertions, 8 deletions

diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c
index e5f5f48d69d2..3affd180baac 100644
--- a/drivers/bus/ti-sysc.c
+++ b/drivers/bus/ti-sysc.c
@@ -1275,13 +1275,6 @@ static const struct sysc_revision_quirk sysc_revision_quirks[] = {
 		   SYSC_QUIRK_LEGACY_IDLE),
 	SYSC_QUIRK("smartreflex", 0, -ENODEV, 0x38, -ENODEV, 0x00000000, 0xffffffff,
 		   SYSC_QUIRK_LEGACY_IDLE),
-	SYSC_QUIRK("timer", 0, 0, 0x10, 0x14, 0x00000015, 0xffffffff,
-		   0),
-	/* Some timers on omap4 and later */
-	SYSC_QUIRK("timer", 0, 0, 0x10, -ENODEV, 0x50002100, 0xffffffff,
-		   0),
-	SYSC_QUIRK("timer", 0, 0, 0x10, -ENODEV, 0x4fff1301, 0xffff00ff,
-		   0),
 	SYSC_QUIRK("uart", 0, 0x50, 0x54, 0x58, 0x00000046, 0xffffffff,
 		   SYSC_QUIRK_SWSUP_SIDLE | SYSC_QUIRK_LEGACY_IDLE),
 	SYSC_QUIRK("uart", 0, 0x50, 0x54, 0x58, 0x00000052, 0xffffffff,
@@ -1404,6 +1397,13 @@ static const struct sysc_revision_quirk sysc_revision_quirks[] = {
 	SYSC_QUIRK("slimbus", 0, 0, 0x10, -ENODEV, 0x40002903, 0xffffffff, 0),
 	SYSC_QUIRK("spinlock", 0, 0, 0x10, -ENODEV, 0x50020000, 0xffffffff, 0),
 	SYSC_QUIRK("rng", 0, 0x1fe0, 0x1fe4, -ENODEV, 0x00000020, 0xffffffff, 0),
+	SYSC_QUIRK("timer", 0, 0, 0x10, 0x14, 0x00000013, 0xffffffff, 0),
+	SYSC_QUIRK("timer", 0, 0, 0x10, 0x14, 0x00000015, 0xffffffff, 0),
+	/* Some timers on omap4 and later */
+	SYSC_QUIRK("timer", 0, 0, 0x10, -ENODEV, 0x50002100, 0xffffffff, 0),
+	SYSC_QUIRK("timer", 0, 0, 0x10, -ENODEV, 0x4fff1301, 0xffff00ff, 0),
+	SYSC_QUIRK("timer32k", 0, 0, 0x4, -ENODEV, 0x00000040, 0xffffffff, 0),
+	SYSC_QUIRK("timer32k", 0, 0, 0x4, -ENODEV, 0x00000011, 0xffffffff, 0),
 	SYSC_QUIRK("timer32k", 0, 0, 0x4, -ENODEV, 0x00000060, 0xffffffff, 0),
 	SYSC_QUIRK("tpcc", 0, 0, -ENODEV, -ENODEV, 0x40014c00, 0xffffffff, 0),
 	SYSC_QUIRK("usbhstll", 0, 0, 0x10, 0x14, 0x00000004, 0xffffffff, 0),
@@ -2744,6 +2744,17 @@ static int sysc_init_soc(struct sysc *ddata)
 	if (match && match->data)
 		sysc_soc->soc = (int)match->data;
 
+	/* Ignore devices that are not available on HS and EMU SoCs */
+	if (!sysc_soc->general_purpose) {
+		switch (sysc_soc->soc) {
+		case SOC_3430 ... SOC_3630:
+			sysc_add_disabled(0x48304000);	/* timer12 */
+			break;
+		default:
+			break;
+		};
+	}
+
 	match = soc_device_match(sysc_soc_feat_match);
 	if (!match)
 		return 0;
diff --git a/drivers/clk/ti/clk-816x.c b/drivers/clk/ti/clk-816x.c
index 7d215cdf9dda..9daf3825f289 100644
--- a/drivers/clk/ti/clk-816x.c
+++ b/drivers/clk/ti/clk-816x.c
@@ -73,6 +73,7 @@ static const char *enable_init_clks[] = {
 	"ddr_pll_clk1",
 	"ddr_pll_clk2",
 	"ddr_pll_clk3",
+	"sysclk6_ck",
 };
 
 int __init dm816x_dt_clk_init(void)
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 641ba5383ab5..bdda1a2e4097 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_CLKSRC_MMIO)	+= mmio.o
 obj-$(CONFIG_DAVINCI_TIMER)	+= timer-davinci.o
 obj-$(CONFIG_DIGICOLOR_TIMER)	+= timer-digicolor.o
 obj-$(CONFIG_OMAP_DM_TIMER)	+= timer-ti-dm.o
+obj-$(CONFIG_OMAP_DM_TIMER)	+= timer-ti-dm-systimer.o
 obj-$(CONFIG_DW_APB_TIMER)	+= dw_apb_timer.o
 obj-$(CONFIG_DW_APB_TIMER_OF)	+= dw_apb_timer_of.o
 obj-$(CONFIG_FTTMR010_TIMER)	+= timer-fttmr010.o
diff --git a/drivers/clocksource/timer-ti-32k.c b/drivers/clocksource/timer-ti-32k.c
index abd5f158d6e2..ae12bbf3d68c 100644
--- a/drivers/clocksource/timer-ti-32k.c
+++ b/drivers/clocksource/timer-ti-32k.c
@@ -24,6 +24,7 @@
  * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
  */
 
+#include <linux/clk.h>
 #include <linux/init.h>
 #include <linux/time.h>
 #include <linux/sched_clock.h>
@@ -76,6 +77,49 @@ static u64 notrace omap_32k_read_sched_clock(void)
 	return ti_32k_read_cycles(&ti_32k_timer.cs);
 }
 
+static void __init ti_32k_timer_enable_clock(struct device_node *np,
+					     const char *name)
+{
+	struct clk *clock;
+	int error;
+
+	clock = of_clk_get_by_name(np->parent, name);
+	if (IS_ERR(clock)) {
+		/* Only some SoCs have a separate interface clock */
+		if (PTR_ERR(clock) == -EINVAL && !strncmp("ick", name, 3))
+			return;
+
+		pr_warn("%s: could not get clock %s %li\n",
+			__func__, name, PTR_ERR(clock));
+		return;
+	}
+
+	error = clk_prepare_enable(clock);
+	if (error) {
+		pr_warn("%s: could not enable %s: %i\n",
+			__func__, name, error);
+		return;
+	}
+}
+
+static void __init ti_32k_timer_module_init(struct device_node *np,
+					    void __iomem *base)
+{
+	void __iomem *sysc = base + 4;
+
+	if (!of_device_is_compatible(np->parent, "ti,sysc"))
+		return;
+
+	ti_32k_timer_enable_clock(np, "fck");
+	ti_32k_timer_enable_clock(np, "ick");
+
+	/*
+	 * Force idle module as wkup domain is active with MPU.
+	 * No need to tag the module disabled for ti-sysc probe.
+	 */
+	writel_relaxed(0, sysc);
+}
+
 static int __init ti_32k_timer_init(struct device_node *np)
 {
 	int ret;
@@ -90,6 +134,7 @@ static int __init ti_32k_timer_init(struct device_node *np)
 		ti_32k_timer.cs.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP;
 
 	ti_32k_timer.counter = ti_32k_timer.base;
+	ti_32k_timer_module_init(np, ti_32k_timer.base);
 
 	/*
 	 * 32k sync Counter IP register offsets vary between the highlander
@@ -104,6 +149,8 @@ static int __init ti_32k_timer_init(struct device_node *np)
 	else
 		ti_32k_timer.counter += OMAP2_32KSYNCNT_CR_OFF_LOW;
 
+	pr_info("OMAP clocksource: 32k_counter at 32768 Hz\n");
+
 	ret = clocksource_register_hz(&ti_32k_timer.cs, 32768);
 	if (ret) {
 		pr_err("32k_counter: can't register clocksource\n");
@@ -111,7 +158,6 @@ static int __init ti_32k_timer_init(struct device_node *np)
 	}
 
 	sched_clock_register(omap_32k_read_sched_clock, 32, 32768);
-	pr_info("OMAP clocksource: 32k_counter at 32768 Hz\n");
 
 	return 0;
 }
diff --git a/drivers/clocksource/timer-ti-dm-systimer.c b/drivers/clocksource/timer-ti-dm-systimer.c
new file mode 100644
index 000000000000..7da998d0dd58
--- /dev/null
+++ b/drivers/clocksource/timer-ti-dm-systimer.c
@@ -0,0 +1,727 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include <linux/clk.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.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_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;
+	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 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;
+
+	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;
+
+	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") ||
+	    of_machine_is_compatible("timll,omap3-devkit8000")) {
+		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 device_node *np,
+					      const char *name,
+					      unsigned long *rate)
+{
+	struct clk *clock;
+	unsigned long r;
+	int error;
+
+	clock = of_clk_get_by_name(np, name);
+	if ((PTR_ERR(clock) == -EINVAL) && !strncmp(name, "ick", 3))
+		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)
+		return -ENODEV;
+
+	*rate = r;
+
+	return 0;
+}
+
+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)
+{
+	writel_relaxed(0, t->base + t->sysc);
+}
+
+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(np->parent, "fck", &rate);
+	if (error)
+		goto err_unmap;
+
+	t->rate = rate;
+
+	error = dmtimer_systimer_init_clock(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_enable(t);
+	dmtimer_systimer_reset(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;
+
+	writel_relaxed(0xffffffff - cycles, t->base + t->counter);
+	while (readl_relaxed(pend) & WP_TCRR)
+		cpu_relax();
+
+	writel_relaxed(OMAP_TIMER_CTRL_ST, t->base + t->ctrl);
+	while (readl_relaxed(pend) & WP_TCLR)
+		cpu_relax();
+
+	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 */
+	writel_relaxed(clkevt->period, t->base + t->load);
+	while (readl_relaxed(pend) & WP_TLDR)
+		cpu_relax();
+
+	writel_relaxed(clkevt->period, t->base + t->counter);
+	while (readl_relaxed(pend) & WP_TCRR)
+		cpu_relax();
+
+	writel_relaxed(OMAP_TIMER_CTRL_AR | OMAP_TIMER_CTRL_ST,
+		       t->base + t->ctrl);
+	while (readl_relaxed(pend) & WP_TCLR)
+		cpu_relax();
+
+	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);
+}
+
+static void omap_clockevent_unidle(struct clock_event_device *evt)
+{
+	struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
+	struct dmtimer_systimer *t = &clkevt->t;
+
+	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_clockevent_init(struct device_node *np)
+{
+	struct dmtimer_clockevent *clkevt;
+	struct clock_event_device *dev;
+	struct dmtimer_systimer *t;
+	int error;
+
+	clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL);
+	if (!clkevt)
+		return -ENOMEM;
+
+	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 = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+	dev->rating = 300;
+	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->tick_resume = dmtimer_clockevent_shutdown;
+	dev->cpumask = cpu_possible_mask;
+
+	dev->irq = irq_of_parse_and_map(np, 0);
+	if (!dev->irq) {
+		error = -ENXIO;
+		goto err_out_free;
+	}
+
+	error = dmtimer_systimer_setup(np, &clkevt->t);
+	if (error)
+		goto err_out_free;
+
+	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, "clockevent", 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 clockevent: %s%lu Hz at %pOF\n",
+		of_find_property(np, "ti,timer-alwon", NULL) ?
+		"always-on " : "", t->rate, np->parent);
+
+	clockevents_config_and_register(dev, t->rate,
+					3, /* Timer internal resynch latency */
+					0xffffffff);
+
+	if (of_device_is_compatible(np, "ti,am33xx") ||
+	    of_device_is_compatible(np, "ti,am43")) {
+		dev->suspend = omap_clockevent_idle;
+		dev->resume = omap_clockevent_unidle;
+	}
+
+	return 0;
+
+err_out_unmap:
+	iounmap(t->base);
+
+err_out_free:
+	kfree(clkevt);
+
+	return error;
+}
+
+/* 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);
+}
+
+static void dmtimer_clocksource_resume(struct clocksource *cs)
+{
+	struct dmtimer_clocksource *clksrc = to_dmtimer_clocksource(cs);
+	struct dmtimer_systimer *t = &clksrc->t;
+
+	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;
+
+	if (of_device_is_compatible(np, "ti,am33xx") ||
+	    of_device_is_compatible(np, "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 detectt 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);
+
+	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);