drivers: usb: stm32: Fix data out on control ep

The Linux Compliance tests that are available in the tools/usb folder
can be used to validate a usb stack implementation. When ran those
tests in the current stm32 boards using the testusb sample next it is
possible to see that tests 14 and 21 are failing. Those tests check
corner cases when data is expected to be transfered in the control
endpoint.

This add the missing piece to allow all tests pass when using the
devices in Full Speed. When enabling High Speed the test 13 starts
to failing. The test 13 is about set/clear the halt endpoint.

Fixes #93924

Signed-off-by: BUDKE Gerson Fernando <gerson.budke@leica-geosystems.com>

Author: nandojve

drivers/usb/udc/udc_stm32.c

@@ -322,15 +322,15 @@ static void handle_msg_data_out(struct udc_stm32_data *priv, uint8_t epnum, uint
 	LOG_DBG("DataOut ep 0x%02x",  ep);
 
 	epcfg = udc_get_ep_cfg(dev, ep);
-	udc_ep_set_busy(epcfg, false);
-
 	buf = udc_buf_get(epcfg);
 	if (unlikely(buf == NULL)) {
+		udc_ep_set_busy(epcfg, false);
 		LOG_ERR("ep 0x%02x queue is empty", ep);
 		return;
 	}
 
 	net_buf_add(buf, rx_count);
+	udc_ep_set_busy(epcfg, false);
 
 	if (ep == USB_CONTROL_EP_OUT) {
 		if (udc_ctrl_stage_is_status_out(dev)) {
@@ -353,6 +353,40 @@ static void handle_msg_data_out(struct udc_stm32_data *priv, uint8_t epnum, uint
 	}
 }
 
+static void handle_msg_data_ep0_out(struct udc_stm32_data *priv, uint8_t epnum, uint16_t rx_count)
+{
+	const struct device *dev = priv->dev;
+	struct udc_ep_config *epcfg;
+	uint8_t ep = epnum | USB_EP_DIR_OUT;
+	struct net_buf *buf;
+	uint8_t *data;
+	uint32_t len;
+
+	epcfg = udc_get_ep_cfg(dev, ep);
+	buf = udc_buf_peek(epcfg);
+	if (unlikely(buf == NULL)) {
+		udc_ep_set_busy(epcfg, false);
+		return;
+	}
+
+	len = net_buf_tailroom(buf);
+
+	/* Check if all data was transferred and then go back to normal flow
+	 * otherwise continue receiving data
+	 */
+	LOG_DBG("xfer size: %d, free: %d, size: %d", rx_count, len, buf->size);
+	if (len == rx_count || rx_count < epcfg->mps) {
+		/* busy will be release in handle_msg_data_out() */
+		handle_msg_data_out(priv, epnum, rx_count);
+		return;
+	}
+
+	net_buf_add(buf, rx_count);
+	data = net_buf_tail(buf);
+
+	HAL_PCD_EP_Receive(&priv->pcd, epcfg->addr, data, buf->size);
+}
+
 static void handle_msg_data_in(struct udc_stm32_data *priv, uint8_t epnum)
 {
 	const struct device *dev = priv->dev;
@@ -363,13 +397,14 @@ static void handle_msg_data_in(struct udc_stm32_data *priv, uint8_t epnum)
 	LOG_DBG("DataIn ep 0x%02x",  ep);
 
 	epcfg = udc_get_ep_cfg(dev, ep);
-	udc_ep_set_busy(epcfg, false);
-
 	buf = udc_buf_peek(epcfg);
 	if (unlikely(buf == NULL)) {
+		udc_ep_set_busy(epcfg, false);
 		return;
 	}
 
+	udc_ep_set_busy(epcfg, false);
+
 	if (ep == USB_CONTROL_EP_IN && buf->len) {
 		const struct udc_stm32_config *cfg = dev->config;
 		uint32_t len = MIN(cfg->ep0_mps, buf->len);
@@ -420,22 +455,38 @@ static void handle_msg_data_in(struct udc_stm32_data *priv, uint8_t epnum)
 	}
 }
 
+static void drop_control_transfers(const struct device *dev)
+{
+	struct net_buf *buf;
+
+	buf = udc_buf_get_all(udc_get_ep_cfg(dev, USB_CONTROL_EP_OUT));
+	if (buf != NULL) {
+		net_buf_unref(buf);
+	}
+
+	buf = udc_buf_get_all(udc_get_ep_cfg(dev, USB_CONTROL_EP_IN));
+	if (buf != NULL) {
+		net_buf_unref(buf);
+	}
+}
+
 static void handle_msg_setup(struct udc_stm32_data *priv)
 {
 	struct usb_setup_packet *setup = (void *)priv->pcd.Setup;
 	const struct device *dev = priv->dev;
 	struct net_buf *buf;
 	int err;
 
+	drop_control_transfers(dev);
+
 	buf = udc_ctrl_alloc(dev, USB_CONTROL_EP_OUT, sizeof(struct usb_setup_packet));
 	if (buf == NULL) {
 		LOG_ERR("Failed to allocate for setup");
 		return;
 	}
 
+	net_buf_add_mem(buf, setup, sizeof(struct usb_setup_packet));
 	udc_ep_buf_set_setup(buf);
-	memcpy(buf->data, setup, 8);
-	net_buf_add(buf, 8);
 
 	udc_ctrl_update_stage(dev, buf);
 
@@ -450,13 +501,16 @@ static void handle_msg_setup(struct udc_stm32_data *priv)
 
 	if (udc_ctrl_stage_is_data_out(dev)) {
 		/*  Allocate and feed buffer for data OUT stage */
+		LOG_DBG("s:%p|feed for -out-", (void *)buf);
 		err = usbd_ctrl_feed_dout(dev, udc_data_stage_length(buf));
 		if (err == -ENOMEM) {
 			udc_submit_ep_event(dev, buf, err);
 		}
 	} else if (udc_ctrl_stage_is_data_in(dev)) {
+		LOG_DBG("s:%p|feed for -in-status", (void *)buf);
 		udc_ctrl_submit_s_in_status(dev);
 	} else {
+		LOG_DBG("s:%p|no data", (void *)buf);
 		udc_ctrl_submit_s_status(dev);
 	}
 }
@@ -477,7 +531,12 @@ static void udc_stm32_thread_handler(void *arg1, void *arg2, void *arg3)
 			handle_msg_data_in(priv, msg.ep);
 			break;
 		case UDC_STM32_MSG_DATA_OUT:
-			handle_msg_data_out(priv, msg.ep, msg.rx_count);
+			/* workaround to xfer data stage on ep0 */
+			if (msg.ep == USB_CONTROL_EP_OUT) {
+				handle_msg_data_ep0_out(priv, msg.ep, msg.rx_count);
+			} else {
+				handle_msg_data_out(priv, msg.ep, msg.rx_count);
+			}
 			break;
 		}
 	}