drivers: counter native: Add top value conf and multi channel support

The counter_native_posix driver currently does not support top value
configuration, i.e. `ctr_set_top_value` returns `-ENOTSUP`. This commit
adds support for top value configuration, and with the counter API now
fully implemented, adds `counter` to `supported` peripherals for
native_posix target.
It also resolves an existing bug in which the
counter ISR did not reset upon reaching `TOP_VALUE`.
And adds support for multiple channels

Signed-off-by: Jason Wright <jason@jpw.nyc>
Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>

boards/posix/native_posix/hw_counter.c

@@ -17,6 +17,7 @@ static bool counter_running;
 static uint64_t counter_value;
 static uint64_t counter_target;
 static uint64_t counter_period;
+static uint64_t counter_wrap;
 
 /**
  * Initialize the counter with prescaler of HW
@@ -28,6 +29,7 @@ void hw_counter_init(void)
 	counter_value = 0;
 	counter_running = false;
 	counter_period = NEVER;
+	counter_wrap = NEVER;
 }
 
 void hw_counter_triggered(void)
@@ -38,7 +40,7 @@ void hw_counter_triggered(void)
 	}
 
 	hw_counter_timer = hwm_get_time() + counter_period;
-	counter_value = counter_value + 1;
+	counter_value = (counter_value + 1) % counter_wrap;
 
 	if (counter_value == counter_target) {
 		hw_irq_ctrl_set_irq(COUNTER_EVENT_IRQ);
@@ -54,6 +56,16 @@ void hw_counter_set_period(uint64_t period)
 	counter_period = period;
 }
 
+/*
+ * Set the count value at which the counter will wrap
+ * The counter will count up to  (counter_wrap-1), i.e.:
+ * 0, 1, 2,.., (counter_wrap - 1), 0
+ */
+void hw_counter_set_wrap_value(uint64_t wrap_value)
+{
+	counter_wrap = wrap_value;
+}
+
 /**
  * Starts the counter. It must be previously configured with
  * hw_counter_set_period() and hw_counter_set_target().
@@ -82,6 +94,11 @@ void hw_counter_stop(void)
 	hwm_find_next_timer();
 }
 
+bool hw_counter_is_started(void)
+{
+	return counter_running;
+}
+
 /**
  * Returns the current counter value.
  */
@@ -90,6 +107,14 @@ uint64_t hw_counter_get_value(void)
 	return counter_value;
 }
 
+/**
+ * Resets the counter value.
+ */
+void hw_counter_reset(void)
+{
+	counter_value = 0;
+}
+
 /**
  * Configures the counter to generate an interrupt
  * when its count value reaches target.

boards/posix/native_posix/hw_counter.h

@@ -18,9 +18,12 @@ void hw_counter_triggered(void);
 
 void hw_counter_set_period(uint64_t period);
 void hw_counter_set_target(uint64_t counter_target);
+void hw_counter_set_wrap_value(uint64_t wrap_value);
 void hw_counter_start(void);
 void hw_counter_stop(void);
+bool hw_counter_is_started(void);
 uint64_t hw_counter_get_value(void);
+void hw_counter_reset(void);
 
 #ifdef __cplusplus
 }

boards/posix/native_posix/native_posix.yaml

@@ -10,6 +10,7 @@ toolchain:
   - llvm
 supported:
   - can
+  - counter
   - eeprom
   - netif:eth
   - usb_device

boards/posix/native_posix/native_posix_64.yaml

@@ -10,6 +10,7 @@ toolchain:
   - llvm
 supported:
   - can
+  - counter
   - eeprom
   - netif:eth
   - usb_device

boards/posix/native_sim/native_sim.yaml

@@ -10,6 +10,7 @@ toolchain:
   - llvm
 supported:
   - can
+  - counter
   - eeprom
   - netif:eth
   - usb_device

boards/posix/native_sim/native_sim_64.yaml

@@ -10,6 +10,7 @@ toolchain:
   - llvm
 supported:
   - can
+  - counter
   - eeprom
   - netif:eth
   - usb_device

drivers/counter/Kconfig.native_posix

@@ -10,3 +10,8 @@ config COUNTER_NATIVE_POSIX_FREQUENCY
 	int "native_posix counter frequency in Hz"
 	default 1000
 	depends on COUNTER_NATIVE_POSIX
+
+config COUNTER_NATIVE_POSIX_NBR_CHANNELS
+	int "native counter, number of channels"
+	default 4
+	depends on COUNTER_NATIVE_POSIX

drivers/counter/counter_native_posix.c

@@ -6,6 +6,7 @@
 
 #define DT_DRV_COMPAT zephyr_native_posix_counter
 
+#include <string.h>
 #include <zephyr/device.h>
 #include <zephyr/drivers/counter.h>
 #include <zephyr/irq.h>
@@ -14,38 +15,80 @@
 #include <limits.h>
 
 #define DRIVER_CONFIG_INFO_FLAGS (COUNTER_CONFIG_INFO_COUNT_UP)
-#define DRIVER_CONFIG_INFO_CHANNELS 1
+#define DRIVER_CONFIG_INFO_CHANNELS CONFIG_COUNTER_NATIVE_POSIX_NBR_CHANNELS
 #define COUNTER_NATIVE_POSIX_IRQ_FLAGS (0)
 #define COUNTER_NATIVE_POSIX_IRQ_PRIORITY (2)
 
 #define COUNTER_PERIOD (USEC_PER_SEC / CONFIG_COUNTER_NATIVE_POSIX_FREQUENCY)
 #define TOP_VALUE (UINT_MAX)
 
-static struct counter_alarm_cfg pending_alarm;
-static bool is_alarm_pending;
+static struct counter_alarm_cfg pending_alarm[DRIVER_CONFIG_INFO_CHANNELS];
+static bool is_alarm_pending[DRIVER_CONFIG_INFO_CHANNELS];
+static struct counter_top_cfg top;
+static bool is_top_set;
 static const struct device *device;
 
+static void schedule_next_isr(void)
+{
+	int64_t current_value = hw_counter_get_value();
+	uint32_t next_time = top.ticks; /* top.ticks is TOP_VALUE if is_top_set == false */
+
+	if (current_value == top.ticks) {
+		current_value = -1;
+	}
+
+	for (int i = 0; i < DRIVER_CONFIG_INFO_CHANNELS; i++) {
+		if (is_alarm_pending[i]) {
+			if (pending_alarm[i].ticks > current_value) {
+				/* If the alarm is not after a wrap */
+				next_time = MIN(pending_alarm[i].ticks, next_time);
+			}
+		}
+	}
+
+	/* We will at least get an interrupt at top.ticks even if is_top_set == false,
+	 * which is fine. We may use that to set the next alarm if needed
+	 */
+	hw_counter_set_target(next_time);
+}
+
 static void counter_isr(const void *arg)
 {
 	ARG_UNUSED(arg);
 	uint32_t current_value = hw_counter_get_value();
 
-	if (is_alarm_pending) {
-		is_alarm_pending = false;
-		pending_alarm.callback(device, 0, current_value,
-				       pending_alarm.user_data);
+	for (int i = 0; i < DRIVER_CONFIG_INFO_CHANNELS; i++) {
+		if (is_alarm_pending[i] && (current_value == pending_alarm[i].ticks)) {
+			is_alarm_pending[i] = false;
+			if (pending_alarm[i].callback) {
+				pending_alarm[i].callback(device, i, current_value,
+							  pending_alarm[i].user_data);
+			}
+		}
 	}
+
+	if (is_top_set && (current_value == top.ticks)) {
+		if (top.callback) {
+			top.callback(device, top.user_data);
+		}
+	}
+
+	schedule_next_isr();
 }
 
 static int ctr_init(const struct device *dev)
 {
 	device = dev;
-	is_alarm_pending = false;
+	memset(is_alarm_pending, 0, sizeof(is_alarm_pending));
+	is_top_set = false;
+	top.ticks = TOP_VALUE;
 
 	IRQ_CONNECT(COUNTER_EVENT_IRQ, COUNTER_NATIVE_POSIX_IRQ_PRIORITY,
 		    counter_isr, NULL, COUNTER_NATIVE_POSIX_IRQ_FLAGS);
+	irq_enable(COUNTER_EVENT_IRQ);
 	hw_counter_set_period(COUNTER_PERIOD);
-	hw_counter_set_target(TOP_VALUE);
+	hw_counter_set_wrap_value((uint64_t)top.ticks + 1);
+	hw_counter_reset();
 
 	return 0;
 }
@@ -54,6 +97,7 @@ static int ctr_start(const struct device *dev)
 {
 	ARG_UNUSED(dev);
 
+	schedule_next_isr();
 	hw_counter_start();
 	return 0;
 }
@@ -80,19 +124,56 @@ static uint32_t ctr_get_pending_int(const struct device *dev)
 	return 0;
 }
 
+static bool is_any_alarm_pending(void)
+{
+	for (int i = 0; i < DRIVER_CONFIG_INFO_CHANNELS; i++) {
+		if (is_alarm_pending[i]) {
+			return true;
+		}
+	}
+	return false;
+}
+
 static int ctr_set_top_value(const struct device *dev,
 			     const struct counter_top_cfg *cfg)
 {
 	ARG_UNUSED(dev);
-	ARG_UNUSED(cfg);
 
-	posix_print_warning("%s not supported\n", __func__);
-	return -ENOTSUP;
+	if (is_any_alarm_pending()) {
+		posix_print_warning("Can't set top value while alarm is active\n");
+		return -EBUSY;
+	}
+
+	uint32_t current_value = hw_counter_get_value();
+
+	if (cfg->flags & COUNTER_TOP_CFG_DONT_RESET) {
+		if (current_value >= cfg->ticks) {
+			if (cfg->flags & COUNTER_TOP_CFG_RESET_WHEN_LATE) {
+				hw_counter_reset();
+			}
+			return -ETIME;
+		}
+	} else {
+		hw_counter_reset();
+	}
+
+	top = *cfg;
+	hw_counter_set_wrap_value((uint64_t)top.ticks + 1);
+
+	if ((cfg->ticks == TOP_VALUE) && !cfg->callback) {
+		is_top_set = false;
+	} else {
+		is_top_set = true;
+	}
+
+	schedule_next_isr();
+
+	return 0;
 }
 
 static uint32_t ctr_get_top_value(const struct device *dev)
 {
-	return TOP_VALUE;
+	return top.ticks;
 }
 
 static int ctr_set_alarm(const struct device *dev, uint8_t chan_id,
@@ -100,21 +181,31 @@ static int ctr_set_alarm(const struct device *dev, uint8_t chan_id,
 {
 	ARG_UNUSED(dev);
 
-	if (chan_id >= DRIVER_CONFIG_INFO_CHANNELS) {
-		posix_print_warning("channel %u is not supported\n", chan_id);
-		return -ENOTSUP;
-	}
+	if (is_alarm_pending[chan_id])
+		return -EBUSY;
 
-	pending_alarm = *alarm_cfg;
-	is_alarm_pending = true;
+	uint32_t ticks = alarm_cfg->ticks;
+
+	if (ticks > top.ticks) {
+		posix_print_warning("Alarm ticks %u exceed top ticks %u\n", ticks,
+				top.ticks);
+		return -EINVAL;
+	}
 
 	if (!(alarm_cfg->flags & COUNTER_ALARM_CFG_ABSOLUTE)) {
-		pending_alarm.ticks =
-			hw_counter_get_value() + pending_alarm.ticks;
+		uint32_t current_value = hw_counter_get_value();
+
+		ticks += current_value;
+		if (ticks > top.ticks) { /* Handle wrap arounds */
+			ticks -= (top.ticks + 1); /* The count period is top.ticks + 1 */
+		}
 	}
 
-	hw_counter_set_target(pending_alarm.ticks);
-	irq_enable(COUNTER_EVENT_IRQ);
+	pending_alarm[chan_id] = *alarm_cfg;
+	pending_alarm[chan_id].ticks = ticks;
+	is_alarm_pending[chan_id] = true;
+
+	schedule_next_isr();
 
 	return 0;
 }
@@ -123,12 +214,14 @@ static int ctr_cancel_alarm(const struct device *dev, uint8_t chan_id)
 {
 	ARG_UNUSED(dev);
 
-	if (chan_id >= DRIVER_CONFIG_INFO_CHANNELS) {
-		posix_print_warning("channel %u is not supported\n", chan_id);
+	if (!hw_counter_is_started()) {
+		posix_print_warning("Counter not started\n");
 		return -ENOTSUP;
 	}
 
-	is_alarm_pending = false;
+	is_alarm_pending[chan_id] = false;
+
+	schedule_next_isr();
 
 	return 0;
 }