subsys: usb: host: support multiple devices under hub

1. When hub is used, need to consider about multiple
devices are attached. Remove the root member of
usbh_context.
2. Add usbh_device_get_root and usbh_device_is_root
function to check root device.

Signed-off-by: Aiden Hu <[email protected]>

Author: AidenHu

include/zephyr/usb/usbh.h

@@ -58,8 +58,6 @@ struct usbh_context {
 	struct usbh_status status;
 	/** USB device list */
 	sys_dlist_t udevs;
-	/** USB root device */
-	struct usb_device *root;
 	/** Allocated device addresses bit array */
 	struct sys_bitarray *addr_ba;
 };

subsys/usb/host/usbh_core.c

@@ -50,44 +50,52 @@ static void dev_connected_handler(struct usbh_context *const ctx,
 				  const struct uhc_event *const event)
 {
 	int ret;
+	struct usb_device *udev;
 
 	LOG_DBG("Device connected event");
-	if (ctx->root != NULL) {
-		LOG_ERR("Device already connected");
-		usbh_device_free(ctx->root);
-		ctx->root = NULL;
-	}
 
-	ctx->root = usbh_device_alloc(ctx);
-	if (ctx->root == NULL) {
+	udev = usbh_device_alloc(ctx);
+	if (udev == NULL) {
 		LOG_ERR("Failed allocate new device");
 		return;
 	}
 
-	ctx->root->state = USB_STATE_DEFAULT;
+	udev->state = USB_STATE_DEFAULT;
 
 	if (event->type == UHC_EVT_DEV_CONNECTED_HS) {
-		ctx->root->speed = USB_SPEED_SPEED_HS;
+		udev->speed = USB_SPEED_SPEED_HS;
 	} else {
-		ctx->root->speed = USB_SPEED_SPEED_FS;
+		udev->speed = USB_SPEED_SPEED_FS;
 	}
 
-	if (usbh_device_init(ctx->root)) {
+	k_mutex_lock(&ctx->mutex, K_FOREVER);
+	sys_dlist_append(&ctx->udevs, &udev->node);
+	k_mutex_unlock(&ctx->mutex);
+
+	if (usbh_device_init(udev)) {
 		LOG_ERR("Failed to reset new USB device");
+		sys_dlist_remove(&udev->node);
 	}
 
-	ret = usbh_class_probe_all(ctx->root);
+	ret = usbh_class_probe_all(udev);
 	if (ret != 0) {
 		LOG_ERR("Failed to probe classes for this new USB device, %d", ret);
 	}
 }
 
 static void dev_removed_handler(struct usbh_context *const ctx)
 {
-	if (ctx->root != NULL) {
-		usbh_class_remove_all(ctx->root);
-		usbh_device_free(ctx->root);
-		ctx->root = NULL;
+	struct usb_device *udev = NULL;
+	
+	udev = usbh_device_get_root(ctx);
+	if (udev != NULL) {
+		usbh_class_remove_all(udev);
+
+		k_mutex_lock(&ctx->mutex, K_FOREVER);
+		sys_dlist_remove(&udev->node);
+		k_mutex_unlock(&ctx->mutex);
+
+		usbh_device_free(udev);
 		LOG_DBG("Device removed");
 	} else {
 		LOG_DBG("Spurious device removed event");

subsys/usb/host/usbh_device.c

@@ -447,10 +447,39 @@ int usbh_device_set_configuration(struct usb_device *const udev, const uint8_t n
 	return err;
 }
 
+struct usb_device *usbh_device_get_root(struct usbh_context *const ctx)
+{
+	sys_dnode_t *node;
+
+	if (ctx == NULL) {
+		return NULL;
+	}
+
+	node = sys_dlist_peek_head(&ctx->udevs);
+	if (node == NULL) {
+		/* No devices in the list */
+		return NULL;
+	}
+
+	/* Get the usb_device structure from the node */
+	return CONTAINER_OF(node, struct usb_device, node);
+}
+
+bool usbh_device_is_root(struct usbh_context *const ctx,
+			struct usb_device *const udev)
+{
+	if (ctx == NULL || udev == NULL) {
+		return false;
+	}
+
+	return sys_dlist_peek_head(&ctx->udevs) == &udev->node;
+}
+
 int usbh_device_init(struct usb_device *const udev)
 {
 	struct usbh_context *const uhs_ctx = udev->ctx;
 	uint8_t new_addr;
+	uint8_t device_count = 0;
 	int err;
 
 	if (udev->state != USB_STATE_DEFAULT) {
@@ -464,11 +493,15 @@ int usbh_device_init(struct usb_device *const udev)
 		return err;
 	}
 
-	/* FIXME: The port to which the device is connected should be reset. */
-	err = uhc_bus_reset(uhs_ctx->dev);
-	if (err) {
-		LOG_ERR("Failed to signal bus reset");
-		return err;
+	device_count = sys_dlist_len(&uhs_ctx->udevs);
+
+	/* Only reset bus if this is the root device. */
+	if (device_count == 1U) {
+		err = uhc_bus_reset(uhs_ctx->dev);
+		if (err) {
+			LOG_ERR("Failed to signal bus reset");
+			return err;
+		}
 	}
 
 	/*

subsys/usb/host/usbh_device.h

@@ -36,6 +36,13 @@ int usbh_device_interface_set(struct usb_device *const udev,
 			      const uint8_t iface, const uint8_t alt,
 			      const bool dry);
 
+/* Get root USB device */
+struct usb_device *usbh_device_get_root(struct usbh_context *const ctx);
+
+/* Check if USB device is root */
+bool usbh_device_is_root(struct usbh_context *const ctx,
+			struct usb_device *const udev);
+
 /* Wrappers around to avoid glue UHC calls. */
 static inline struct uhc_transfer *usbh_xfer_alloc(struct usb_device *udev,
 						   const uint8_t ep,