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Message-Id: <20250623-topic-ti-dm-clkevt-v6-16-v1-3-b00086761ee1@baylibre.com>
Date: Mon, 23 Jun 2025 21:24:30 +0200
From: Markus Schneider-Pargmann <msp@...libre.com>
To: Daniel Lezcano <daniel.lezcano@...aro.org>,
Thomas Gleixner <tglx@...utronix.de>
Cc: Vishal Mahaveer <vishalm@...com>, Kevin Hilman <khilman@...libre.com>,
Dhruva Gole <d-gole@...com>, Sebin Francis <sebin.francis@...com>,
Kendall Willis <k-willis@...com>, Akashdeep Kaur <a-kaur@...com>,
linux-kernel@...r.kernel.org, Markus Schneider-Pargmann <msp@...libre.com>
Subject: [PATCH 3/3] clocksource/drivers/timer-ti-dm: Add clockevent
support
Add support for using the TI Dual-Mode Timer for clockevents. The second
always on device with the "ti,timer-alwon" property is selected to be
used for clockevents. The first one is used as clocksource.
This allows clockevents to be setup independently of the CPU.
Signed-off-by: Markus Schneider-Pargmann <msp@...libre.com>
---
drivers/clocksource/timer-ti-dm.c | 138 ++++++++++++++++++++++++++++++++++++--
1 file changed, 133 insertions(+), 5 deletions(-)
diff --git a/drivers/clocksource/timer-ti-dm.c b/drivers/clocksource/timer-ti-dm.c
index 085609ba2d249dcc8f53c8aaa831d8fbe69b3753..a17e3e81508793a46cdee815bde3ad17fedd55e7 100644
--- a/drivers/clocksource/timer-ti-dm.c
+++ b/drivers/clocksource/timer-ti-dm.c
@@ -21,8 +21,10 @@
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/clocksource.h>
+#include <linux/clockchips.h>
#include <linux/cpu_pm.h>
#include <linux/module.h>
+#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/err.h>
@@ -158,7 +160,14 @@ struct dmtimer_clocksource {
unsigned int loadval;
};
+struct omap_dm_timer_clockevent {
+ struct clock_event_device dev;
+ struct dmtimer *timer;
+ u32 period;
+};
+
static resource_size_t omap_dm_timer_clocksource_base;
+static resource_size_t omap_dm_timer_clockevent_base;
static void __iomem *omap_dm_timer_sched_clock_counter;
enum {
@@ -1091,6 +1100,9 @@ static void omap_dm_timer_find_alwon(void)
{
struct device_node *np;
+ if (omap_dm_timer_clocksource_base && omap_dm_timer_clockevent_base)
+ return;
+
for_each_matching_node(np, omap_timer_match) {
struct resource res;
@@ -1103,13 +1115,22 @@ static void omap_dm_timer_find_alwon(void)
if (of_address_to_resource(np, 0, &res))
continue;
- omap_dm_timer_clocksource_base = res.start;
+ if (!omap_dm_timer_clocksource_base) {
+ omap_dm_timer_clocksource_base = res.start;
+ continue;
+ }
- of_node_put(np);
- return;
+ if (res.start != omap_dm_timer_clocksource_base) {
+ omap_dm_timer_clockevent_base = res.start;
+
+ of_node_put(np);
+ return;
+ }
}
- omap_dm_timer_clocksource_base = -1;
+ if (!omap_dm_timer_clocksource_base)
+ omap_dm_timer_clocksource_base = -1;
+ omap_dm_timer_clockevent_base = -1;
}
static struct dmtimer_clocksource *omap_dm_timer_to_clocksource(struct clocksource *cs)
@@ -1188,6 +1209,105 @@ static int omap_dm_timer_setup_clocksource(struct dmtimer *timer)
return 0;
}
+static struct omap_dm_timer_clockevent *to_dm_timer_clockevent(struct clock_event_device *evt)
+{
+ return container_of(evt, struct omap_dm_timer_clockevent, dev);
+}
+
+static int omap_dm_timer_evt_set_next_event(unsigned long cycles,
+ struct clock_event_device *evt)
+{
+ struct omap_dm_timer_clockevent *clkevt = to_dm_timer_clockevent(evt);
+ struct dmtimer *timer = clkevt->timer;
+
+ dmtimer_write(timer, OMAP_TIMER_COUNTER_REG, 0xffffffff - cycles);
+ dmtimer_write(timer, OMAP_TIMER_CTRL_REG, OMAP_TIMER_CTRL_ST);
+
+ return 0;
+}
+
+static int omap_dm_timer_evt_shutdown(struct clock_event_device *evt)
+{
+ struct omap_dm_timer_clockevent *clkevt = to_dm_timer_clockevent(evt);
+ struct dmtimer *timer = clkevt->timer;
+
+ __omap_dm_timer_stop(timer);
+
+ return 0;
+}
+
+static int omap_dm_timer_evt_set_periodic(struct clock_event_device *evt)
+{
+ struct omap_dm_timer_clockevent *clkevt = to_dm_timer_clockevent(evt);
+ struct dmtimer *timer = clkevt->timer;
+
+ omap_dm_timer_evt_shutdown(evt);
+
+ omap_dm_timer_set_load(&timer->cookie, clkevt->period);
+ dmtimer_write(timer, OMAP_TIMER_COUNTER_REG, clkevt->period);
+ dmtimer_write(timer, OMAP_TIMER_CTRL_REG,
+ OMAP_TIMER_CTRL_AR | OMAP_TIMER_CTRL_ST);
+
+ return 0;
+}
+
+static irqreturn_t omap_dm_timer_evt_interrupt(int irq, void *dev_id)
+{
+ struct omap_dm_timer_clockevent *clkevt = dev_id;
+ struct dmtimer *timer = clkevt->timer;
+
+ __omap_dm_timer_write_status(timer, OMAP_TIMER_INT_OVERFLOW);
+
+ clkevt->dev.event_handler(&clkevt->dev);
+
+ return IRQ_HANDLED;
+}
+
+static int omap_dm_timer_setup_clockevent(struct dmtimer *timer)
+{
+ struct device *dev = &timer->pdev->dev;
+ struct omap_dm_timer_clockevent *clkevt;
+ int ret;
+
+ clkevt = devm_kzalloc(dev, sizeof(*clkevt), GFP_KERNEL);
+ if (!clkevt)
+ return -ENOMEM;
+
+ timer->reserved = 1;
+ clkevt->timer = timer;
+
+ clkevt->dev.name = "omap_dm_timer";
+ clkevt->dev.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+ clkevt->dev.rating = 300;
+ clkevt->dev.set_next_event = omap_dm_timer_evt_set_next_event;
+ clkevt->dev.set_state_shutdown = omap_dm_timer_evt_shutdown;
+ clkevt->dev.set_state_periodic = omap_dm_timer_evt_set_periodic;
+ clkevt->dev.set_state_oneshot = omap_dm_timer_evt_shutdown;
+ clkevt->dev.set_state_oneshot_stopped = omap_dm_timer_evt_shutdown;
+ clkevt->dev.tick_resume = omap_dm_timer_evt_shutdown;
+ clkevt->dev.cpumask = cpu_possible_mask;
+ clkevt->period = 0xffffffff - DIV_ROUND_CLOSEST(timer->fclk_rate, HZ);
+
+ __omap_dm_timer_init_regs(timer);
+ __omap_dm_timer_stop(timer);
+ __omap_dm_timer_enable_posted(timer);
+
+ ret = devm_request_irq(dev, timer->irq, omap_dm_timer_evt_interrupt,
+ IRQF_TIMER, "omap_dm_timer_clockevent", clkevt);
+ if (ret) {
+ dev_err(dev, "Failed to request interrupt: %d\n", ret);
+ return ret;
+ }
+
+ __omap_dm_timer_int_enable(timer, OMAP_TIMER_INT_OVERFLOW);
+
+ clockevents_config_and_register(&clkevt->dev, timer->fclk_rate,
+ 3,
+ 0xffffffff);
+
+ return 0;
+}
+
/**
* omap_dm_timer_probe - probe function called for every registered device
* @pdev: pointer to current timer platform device
@@ -1204,7 +1324,7 @@ static int omap_dm_timer_probe(struct platform_device *pdev)
struct resource *res;
int ret;
- if (!omap_dm_timer_clocksource_base)
+ if (!omap_dm_timer_clocksource_base || !omap_dm_timer_clockevent_base)
omap_dm_timer_find_alwon();
pdata = of_device_get_match_data(dev);
@@ -1281,6 +1401,14 @@ static int omap_dm_timer_probe(struct platform_device *pdev)
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (omap_dm_timer_clockevent_base && res &&
+ res->start == omap_dm_timer_clockevent_base &&
+ !IS_ERR_OR_NULL(timer->fclk)) {
+ ret = omap_dm_timer_setup_clockevent(timer);
+ if (ret)
+ return ret;
+ }
+
if (omap_dm_timer_clocksource_base && res &&
res->start == omap_dm_timer_clocksource_base &&
!IS_ERR_OR_NULL(timer->fclk)) {
--
2.49.0
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