usb: dwc2: Simplify wait_for_chhltd(), remove ignore_ack

A transfer is completed if the XFERCOMP flag is set, irrespective of the
ACK flag. BULK OUT transfers to some HS devices complete without having
the ACK flag set, which signal the devices has responded with an NYET
to the transfer (PING protocol).
The new behaviour matches the Linux kernel minus any PING protocol.

Also see 5966defabdcc (usb: dwc2: fix bulk transfers)

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>

drivers/usb/host/dwc2.c

@@ -729,10 +729,8 @@ static int dwc_otg_submit_rh_msg(struct dwc2_priv *priv, struct usb_device *dev,
 	return stat;
 }
 
-int wait_for_chhltd(struct dwc2_core_regs *regs, uint32_t *sub, int *toggle,
-		    bool ignore_ack)
+int wait_for_chhltd(struct dwc2_core_regs *regs, uint32_t *sub, int *toggle)
 {
-	uint32_t hcint_comp_hlt_ack = DWC2_HCINT_XFERCOMP | DWC2_HCINT_CHHLTD;
 	struct dwc2_hc_regs *hc_regs = &regs->hc_regs[DWC2_HC_CHANNEL];
 	int ret;
 	uint32_t hcint, hctsiz;
@@ -742,25 +740,22 @@ int wait_for_chhltd(struct dwc2_core_regs *regs, uint32_t *sub, int *toggle,
 		return ret;
 
 	hcint = readl(&hc_regs->hcint);
-	if (hcint & (DWC2_HCINT_NAK | DWC2_HCINT_FRMOVRUN))
-		return -EAGAIN;
-	if (ignore_ack)
-		hcint &= ~DWC2_HCINT_ACK;
-	else
-		hcint_comp_hlt_ack |= DWC2_HCINT_ACK;
-	if (hcint != hcint_comp_hlt_ack) {
-		debug("%s: Error (HCINT=%08x)\n", __func__, hcint);
-		return -EINVAL;
-	}
-
 	hctsiz = readl(&hc_regs->hctsiz);
 	*sub = (hctsiz & DWC2_HCTSIZ_XFERSIZE_MASK) >>
 		DWC2_HCTSIZ_XFERSIZE_OFFSET;
 	*toggle = (hctsiz & DWC2_HCTSIZ_PID_MASK) >> DWC2_HCTSIZ_PID_OFFSET;
 
-	debug("%s: sub=%u toggle=%d\n", __func__, *sub, *toggle);
+	debug("%s: HCINT=%08x sub=%u toggle=%d\n", __func__, hcint, *sub,
+	      *toggle);
 
-	return 0;
+	if (hcint & DWC2_HCINT_XFERCOMP)
+		return 0;
+
+	if (hcint & (DWC2_HCINT_NAK | DWC2_HCINT_FRMOVRUN))
+		return -EAGAIN;
+
+	debug("%s: Error (HCINT=%08x)\n", __func__, hcint);
+	return -EINVAL;
 }
 
 static int dwc2_eptype[] = {
@@ -771,8 +766,7 @@ static int dwc2_eptype[] = {
 };
 
 int chunk_msg(struct dwc2_priv *priv, struct usb_device *dev,
-	      unsigned long pipe, int *pid, int in, void *buffer, int len,
-	      bool ignore_ack)
+	      unsigned long pipe, int *pid, int in, void *buffer, int len)
 {
 	struct dwc2_core_regs *regs = priv->regs;
 	struct dwc2_hc_regs *hc_regs = &regs->hc_regs[DWC2_HC_CHANNEL];
@@ -841,7 +835,7 @@ int chunk_msg(struct dwc2_priv *priv, struct usb_device *dev,
 				(1 << DWC2_HCCHAR_MULTICNT_OFFSET) |
 				DWC2_HCCHAR_CHEN);
 
-		ret = wait_for_chhltd(regs, &sub, pid, ignore_ack);
+		ret = wait_for_chhltd(regs, &sub, pid);
 		if (ret)
 			break;
 
@@ -883,7 +877,7 @@ int _submit_bulk_msg(struct dwc2_priv *priv, struct usb_device *dev,
 	}
 
 	return chunk_msg(priv, dev, pipe, &priv->bulk_data_toggle[devnum][ep],
-			 usb_pipein(pipe), buffer, len, true);
+			 usb_pipein(pipe), buffer, len);
 }
 
 static int _submit_control_msg(struct dwc2_priv *priv, struct usb_device *dev,
@@ -903,14 +897,14 @@ static int _submit_control_msg(struct dwc2_priv *priv, struct usb_device *dev,
 	}
 
 	pid = DWC2_HC_PID_SETUP;
-	ret = chunk_msg(priv, dev, pipe, &pid, 0, setup, 8, true);
+	ret = chunk_msg(priv, dev, pipe, &pid, 0, setup, 8);
 	if (ret)
 		return ret;
 
 	if (buffer) {
 		pid = DWC2_HC_PID_DATA1;
 		ret = chunk_msg(priv, dev, pipe, &pid, usb_pipein(pipe), buffer,
-				len, false);
+				len);
 		if (ret)
 			return ret;
 		act_len = dev->act_len;
@@ -926,7 +920,7 @@ static int _submit_control_msg(struct dwc2_priv *priv, struct usb_device *dev,
 
 	pid = DWC2_HC_PID_DATA1;
 	ret = chunk_msg(priv, dev, pipe, &pid, status_direction,
-			priv->status_buffer, 0, false);
+			priv->status_buffer, 0);
 	if (ret)
 		return ret;