samples: hid-mouse: protect report buffer

Use the message queue to pass the new report from the input callback,
and use a semaphore to protect the report buffer until it is transferred
to the host.

Signed-off-by: Johann Fischer <[email protected]>

Author: jfischer-no

samples/subsys/usb/hid-mouse/prj.conf

@@ -10,3 +10,4 @@ CONFIG_USB_DEVICE_LOG_LEVEL_ERR=y
 
 CONFIG_GPIO=y
 CONFIG_INPUT=y
+CONFIG_INPUT_MODE_SYNCHRONOUS=y

samples/subsys/usb/hid-mouse/src/main.c

@@ -37,8 +37,8 @@ enum mouse_report_idx {
 	MOUSE_REPORT_COUNT = 4,
 };
 
-static uint8_t __aligned(sizeof(void *)) report[MOUSE_REPORT_COUNT];
-static K_SEM_DEFINE(report_sem, 0, 1);
+K_MSGQ_DEFINE(mouse_msgq, MOUSE_REPORT_COUNT, 2, 1);
+static K_SEM_DEFINE(ep_write_sem, 0, 1);
 
 static inline void status_cb(enum usb_dc_status_code status, const uint8_t *param)
 {
@@ -57,9 +57,7 @@ static ALWAYS_INLINE void rwup_if_suspended(void)
 
 static void input_cb(struct input_event *evt)
 {
-	uint8_t tmp[MOUSE_REPORT_COUNT];
-
-	(void)memcpy(tmp, report, sizeof(tmp));
+	static uint8_t tmp[MOUSE_REPORT_COUNT];
 
 	switch (evt->code) {
 	case INPUT_KEY_0:
@@ -88,10 +86,13 @@ static void input_cb(struct input_event *evt)
 		return;
 	}
 
-	if (memcmp(tmp, report, sizeof(tmp))) {
-		memcpy(report, tmp, sizeof(report));
-		k_sem_give(&report_sem);
+	if (k_msgq_put(&mouse_msgq, tmp, K_NO_WAIT) != 0) {
+		LOG_ERR("Failed to put new input event");
 	}
+
+	tmp[MOUSE_X_REPORT_IDX] = 0U;
+	tmp[MOUSE_Y_REPORT_IDX] = 0U;
+
 }
 
 INPUT_CALLBACK_DEFINE(NULL, input_cb);
@@ -120,6 +121,16 @@ static int enable_usb_device_next(void)
 }
 #endif /* defined(CONFIG_USB_DEVICE_STACK_NEXT) */
 
+static void int_in_ready_cb(const struct device *dev)
+{
+	ARG_UNUSED(dev);
+	k_sem_give(&ep_write_sem);
+}
+
+static const struct hid_ops ops = {
+	.int_in_ready = int_in_ready_cb,
+};
+
 int main(void)
 {
 	const struct device *hid_dev;
@@ -148,7 +159,7 @@ int main(void)
 
 	usb_hid_register_device(hid_dev,
 				hid_report_desc, sizeof(hid_report_desc),
-				NULL);
+				&ops);
 
 	usb_hid_init(hid_dev);
 
@@ -163,19 +174,17 @@ int main(void)
 	}
 
 	while (true) {
-		k_sem_take(&report_sem, K_FOREVER);
+		uint8_t __aligned(sizeof(void *)) report[MOUSE_REPORT_COUNT];
+
+		k_msgq_get(&mouse_msgq, &report, K_FOREVER);
 
 		ret = hid_int_ep_write(hid_dev, report, sizeof(report), NULL);
-		report[MOUSE_X_REPORT_IDX] = 0U;
-		report[MOUSE_Y_REPORT_IDX] = 0U;
 		if (ret) {
 			LOG_ERR("HID write error, %d", ret);
-		}
-
-		/* Toggle LED on sent report */
-		ret = gpio_pin_toggle(led0.port, led0.pin);
-		if (ret < 0) {
-			LOG_ERR("Failed to toggle the LED pin, error: %d", ret);
+		} else {
+			k_sem_take(&ep_write_sem, K_FOREVER);
+			/* Toggle LED on sent report */
+			(void)gpio_pin_toggle(led0.port, led0.pin);
 		}
 	}
 	return 0;