[PATCH v2 2/4] thunderbolt: Handle ring interrupt by reading intr status

[Sanjay R Mehta <Sanju.Mehta@amd.com>]

From: Sanjay R Mehta <sanju.mehta@amd.com>

As per USB4 spec by default "Disable ISR Auto-Clear" bit is set to 0,
and the Tx/Rx ring interrupt status is needs to be cleared.

Hence handling it by reading the "Interrupt status" register in the ISR.

Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Sanjay R Mehta <sanju.mehta@amd.com>
---
 drivers/thunderbolt/nhi.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c
index ef01aa6..7ad2202 100644
--- a/drivers/thunderbolt/nhi.c
+++ b/drivers/thunderbolt/nhi.c
@@ -373,11 +373,25 @@ void tb_ring_poll_complete(struct tb_ring *ring)
 }
 EXPORT_SYMBOL_GPL(tb_ring_poll_complete);
 
+static void check_and_clear_intr_status(struct tb_ring *ring)
+{
+	if (!(ring->nhi->pdev->vendor == PCI_VENDOR_ID_INTEL)) {
+		if (ring->is_tx)
+			ioread32(ring->nhi->iobase
+				 + REG_RING_NOTIFY_BASE);
+		else
+			ioread32(ring->nhi->iobase
+				 + REG_RING_NOTIFY_BASE
+				 + 4 * (ring->nhi->hop_count / 32));
+	}
+}
+
 static irqreturn_t ring_msix(int irq, void *data)
 {
 	struct tb_ring *ring = data;
 
 	spin_lock(&ring->nhi->lock);
+	check_and_clear_intr_status(ring);
 	spin_lock(&ring->lock);
 	__ring_interrupt(ring);
 	spin_unlock(&ring->lock);
-- 
2.7.4