linux-kernel - [PATCH v15 07/50] xhci: add helper that checks for unhandled events on a event ring

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Date: Mon, 12 Feb 2024 16:53:39 -0800
From: Wesley Cheng <quic_wcheng@...cinc.com>
To: <srinivas.kandagatla@...aro.org>, <mathias.nyman@...el.com>,
        <perex@...ex.cz>, <conor+dt@...nel.org>, <corbet@....net>,
        <lgirdwood@...il.com>, <andersson@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <gregkh@...uxfoundation.org>,
        <Thinh.Nguyen@...opsys.com>, <broonie@...nel.org>,
        <bgoswami@...cinc.com>, <tiwai@...e.com>, <robh+dt@...nel.org>,
        <konrad.dybcio@...aro.org>
CC: <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-sound@...r.kernel.org>, <linux-usb@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-doc@...r.kernel.org>,
        <alsa-devel@...a-project.org>,
        Mathias Nyman <mathias.nyman@...ux.intel.com>,
        Wesley Cheng <quic_wcheng@...cinc.com>
Subject: [PATCH v15 07/50] xhci: add helper that checks for unhandled events on a event ring

From: Mathias Nyman <mathias.nyman@...ux.intel.com>

Add unhandled_event_trb() that returns true in case xHC hardware has
written new event trbs to the event ring that driver has not yet handled.

Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@...cinc.com>
---
 drivers/usb/host/xhci-ring.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 338b6fddedc3..48388bc16b24 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -113,6 +113,12 @@ static bool last_td_in_urb(struct xhci_td *td)
 	return urb_priv->num_tds_done == urb_priv->num_tds;
 }
 
+static bool unhandled_event_trb(struct xhci_ring *ring)
+{
+	return ((le32_to_cpu(ring->dequeue->event_cmd.flags) & TRB_CYCLE) ==
+		ring->cycle_state);
+}
+
 static void inc_td_cnt(struct urb *urb)
 {
 	struct urb_priv *urb_priv = urb->hcpriv;
@@ -2923,9 +2929,8 @@ static int xhci_handle_event(struct xhci_hcd *xhci, struct xhci_interrupter *ir)
 	}
 
 	event = ir->event_ring->dequeue;
-	/* Does the HC or OS own the TRB? */
-	if ((le32_to_cpu(event->event_cmd.flags) & TRB_CYCLE) !=
-	    ir->event_ring->cycle_state)
+
+	if (!unhandled_event_trb(ir->event_ring))
 		return 0;
 
 	trace_xhci_handle_event(ir->event_ring, &event->generic);