[PATCH] can: kvaser_pciefd: Use a single write when releasing RX buffers

[Martin Jocic <martin.jocic@xxxxxxxxxx>]

We should return from the ISR as fast as possible in order
not to mask a new interrupt.

Signed-off-by: Martin Jocic <martin.jocic@xxxxxxxxxx>
---
 drivers/net/can/kvaser_pciefd.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/drivers/net/can/kvaser_pciefd.c b/drivers/net/can/kvaser_pciefd.c
index a60d9efd5f8d..9ffc3ffb4e8f 100644
--- a/drivers/net/can/kvaser_pciefd.c
+++ b/drivers/net/can/kvaser_pciefd.c
@@ -1686,6 +1686,7 @@ static irqreturn_t kvaser_pciefd_irq_handler(int irq, void *dev)
 	const struct kvaser_pciefd_irq_mask *irq_mask = pcie->driver_data->irq_mask;
 	u32 pci_irq = ioread32(KVASER_PCIEFD_PCI_IRQ_ADDR(pcie));
 	u32 srb_irq = 0;
+	u32 srb_release = 0;
 	int i;

 	if (!(pci_irq & irq_mask->all))
@@ -1699,17 +1700,14 @@ static irqreturn_t kvaser_pciefd_irq_handler(int irq, void *dev)
 			kvaser_pciefd_transmit_irq(pcie->can[i]);
 	}

-	if (srb_irq & KVASER_PCIEFD_SRB_IRQ_DPD0) {
-		/* Reset DMA buffer 0, may trigger new interrupt */
-		iowrite32(KVASER_PCIEFD_SRB_CMD_RDB0,
-			  KVASER_PCIEFD_SRB_ADDR(pcie) + KVASER_PCIEFD_SRB_CMD_REG);
-	}
+	if (srb_irq & KVASER_PCIEFD_SRB_IRQ_DPD0)
+		srb_release |= KVASER_PCIEFD_SRB_CMD_RDB0;

-	if (srb_irq & KVASER_PCIEFD_SRB_IRQ_DPD1) {
-		/* Reset DMA buffer 1, may trigger new interrupt */
-		iowrite32(KVASER_PCIEFD_SRB_CMD_RDB1,
-			  KVASER_PCIEFD_SRB_ADDR(pcie) + KVASER_PCIEFD_SRB_CMD_REG);
-	}
+	if (srb_irq & KVASER_PCIEFD_SRB_IRQ_DPD1)
+		srb_release |= KVASER_PCIEFD_SRB_CMD_RDB1;
+
+	if (srb_release)
+		iowrite32(srb_release, KVASER_PCIEFD_SRB_ADDR(pcie) + KVASER_PCIEFD_SRB_CMD_REG);

 	return IRQ_HANDLED;
 }
--
2.43.0