usb: renesas_usbhs: gadget: Fix usb_ep_set_{halt,wedge}() behavior

According to usb_ep_set_halt()'s description,
__usbhsg_ep_set_halt_wedge() should return -EAGAIN if the IN endpoint
has any queue or data. Otherwise, this driver is possible to cause
just STALL without sending a short packet data on g_mass_storage driver,
and then a few resetting a device happens on a host side during
a usb enumaration.

Fixes: 2f98382dcdfe ("usb: renesas_usbhs: Add Renesas USBHS Gadget")
Cc: <[e-mail]> # v3.0+
Signed-off-by: Yoshihiro Shimoda <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/renesas_usbhs/common.h

···
 /* DCPCTR */
 #define BSTS		(1 << 15)	/* Buffer Status */
 #define SUREQ		(1 << 14)	/* Sending SETUP Token */
+#define INBUFM		(1 << 14)	/* (PIPEnCTR) Transfer Buffer Monitor */
 #define CSSTS		(1 << 12)	/* CSSTS Status */
 #define	ACLRM		(1 << 9)	/* Buffer Auto-Clear Mode */
 #define SQCLR		(1 << 8)	/* Toggle Bit Clear */

drivers/usb/renesas_usbhs/fifo.c

···
 	list_del_init(&pkt->node);
 }
 
-static struct usbhs_pkt *__usbhsf_pkt_get(struct usbhs_pipe *pipe)
+struct usbhs_pkt *__usbhsf_pkt_get(struct usbhs_pipe *pipe)
 {
 	return list_first_entry_or_null(&pipe->list, struct usbhs_pkt, node);
 }

drivers/usb/renesas_usbhs/fifo.h

···
 		    void *buf, int len, int zero, int sequence);
 struct usbhs_pkt *usbhs_pkt_pop(struct usbhs_pipe *pipe, struct usbhs_pkt *pkt);
 void usbhs_pkt_start(struct usbhs_pipe *pipe);
+struct usbhs_pkt *__usbhsf_pkt_get(struct usbhs_pipe *pipe);
 
 #endif /* RENESAS_USB_FIFO_H */

drivers/usb/renesas_usbhs/mod_gadget.c

···
 	struct usbhs_priv *priv = usbhsg_gpriv_to_priv(gpriv);
 	struct device *dev = usbhsg_gpriv_to_dev(gpriv);
 	unsigned long flags;
+	int ret = 0;
 
 	dev_dbg(dev, "set halt %d (pipe %d)\n",
 		halt, usbhs_pipe_number(pipe));
 
 	/********************  spin lock ********************/
 	usbhs_lock(priv, flags);
+
+	/*
+	 * According to usb_ep_set_halt()'s description, this function should
+	 * return -EAGAIN if the IN endpoint has any queue or data. Note
+	 * that the usbhs_pipe_is_dir_in() returns false if the pipe is an
+	 * IN endpoint in the gadget mode.
+	 */
+	if (!usbhs_pipe_is_dir_in(pipe) && (__usbhsf_pkt_get(pipe) ||
+	    usbhs_pipe_contains_transmittable_data(pipe))) {
+		ret = -EAGAIN;
+		goto out;
+	}
 
 	if (halt)
 		usbhs_pipe_stall(pipe);
···
 	else
 		usbhsg_status_clr(gpriv, USBHSG_STATUS_WEDGE);
 
+out:
 	usbhs_unlock(priv, flags);
 	/********************  spin unlock ******************/
 
-	return 0;
+	return ret;
 }
 
 static int usbhsg_ep_set_halt(struct usb_ep *ep, int value)

drivers/usb/renesas_usbhs/pipe.c

···
 	return -EBUSY;
 }
 
+bool usbhs_pipe_contains_transmittable_data(struct usbhs_pipe *pipe)
+{
+	u16 val;
+
+	/* Do not support for DCP pipe */
+	if (usbhs_pipe_is_dcp(pipe))
+		return false;
+
+	val = usbhsp_pipectrl_get(pipe);
+	if (val & INBUFM)
+		return true;
+
+	return false;
+}
+
 /*
  *		PID ctrl
  */

drivers/usb/renesas_usbhs/pipe.h

···
 void usbhs_pipe_clear_without_sequence(struct usbhs_pipe *pipe,
 				       int needs_bfre, int bfre_enable);
 int usbhs_pipe_is_accessible(struct usbhs_pipe *pipe);
+bool usbhs_pipe_contains_transmittable_data(struct usbhs_pipe *pipe);
 void usbhs_pipe_enable(struct usbhs_pipe *pipe);
 void usbhs_pipe_disable(struct usbhs_pipe *pipe);
 void usbhs_pipe_stall(struct usbhs_pipe *pipe);