linux-kernel - [PATCH 10/11] mailbox: bcm-pdc: Simplify interrupt handler logic

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Message-Id: <1479147965-29662-11-git-send-email-rob.rice@broadcom.com>
Date:   Mon, 14 Nov 2016 13:26:04 -0500
From:   Rob Rice <rob.rice@...adcom.com>
To:     Jassi Brar <jassisinghbrar@...il.com>
Cc:     bcm-kernel-feedback-list@...adcom.com,
        linux-kernel@...r.kernel.org, Steve Lin <steven.lin1@...adcom.com>,
        Rob Rice <rob.rice@...adcom.com>
Subject: [PATCH 10/11] mailbox: bcm-pdc: Simplify interrupt handler logic

Earlier versions of the PDC driver registered for both
transmit and receive interrupts. The hard IRQ handler had to
communicate to the soft handler which interrupt(s) had occurred.
The PDC driver no longer registers for tx interrupts. So there is
no reason to save the intstatus. So remove the intstatus member
of the PDC state.

Signed-off-by: Rob Rice <rob.rice@...adcom.com>
Reviewed-by: Andy Gospodarek <gospo@...adcom.com>
---
 drivers/mailbox/bcm-pdc-mailbox.c | 38 +++++++++++++-------------------------
 1 file changed, 13 insertions(+), 25 deletions(-)

diff --git a/drivers/mailbox/bcm-pdc-mailbox.c b/drivers/mailbox/bcm-pdc-mailbox.c
index 8c2aa7c..c1ec17c 100644
--- a/drivers/mailbox/bcm-pdc-mailbox.c
+++ b/drivers/mailbox/bcm-pdc-mailbox.c
@@ -298,14 +298,6 @@ struct pdc_state {
 
 	unsigned int pdc_irq;
 
-	/*
-	 * Last interrupt status read from PDC device. Saved in interrupt
-	 * handler so the handler can clear the interrupt in the device,
-	 * and the interrupt thread called later can know which interrupt
-	 * bits are active.
-	 */
-	unsigned long intstatus;
-
 	/* tasklet for deferred processing after DMA rx interrupt */
 	struct tasklet_struct rx_tasklet;
 
@@ -955,32 +947,30 @@ static irqreturn_t pdc_irq_handler(int irq, void *data)
 	struct pdc_state *pdcs = dev_get_drvdata(dev);
 	u32 intstatus = ioread32(pdcs->pdc_reg_vbase + PDC_INTSTATUS_OFFSET);
 
-	if (likely(intstatus & PDC_RCVINTEN_0))
-		set_bit(PDC_RCVINT_0, &pdcs->intstatus);
-
-	/* Clear interrupt flags in device */
-	iowrite32(intstatus, pdcs->pdc_reg_vbase + PDC_INTSTATUS_OFFSET);
+	if (unlikely(intstatus == 0))
+		return IRQ_NONE;
 
 	/* Disable interrupts until soft handler runs */
 	iowrite32(0, pdcs->pdc_reg_vbase + PDC_INTMASK_OFFSET);
 
+	/* Clear interrupt flags in device */
+	iowrite32(intstatus, pdcs->pdc_reg_vbase + PDC_INTSTATUS_OFFSET);
+
 	/* Wakeup IRQ thread */
-	if (likely(pdcs && (irq == pdcs->pdc_irq) &&
-		   (intstatus & PDC_INTMASK))) {
-		tasklet_schedule(&pdcs->rx_tasklet);
-		return IRQ_HANDLED;
-	}
-	return IRQ_NONE;
+	tasklet_schedule(&pdcs->rx_tasklet);
+	return IRQ_HANDLED;
 }
 
+/**
+ * pdc_tasklet_cb() - Tasklet callback that runs the deferred processing after
+ * a DMA receive interrupt. Reenables the receive interrupt.
+ * @data: PDC state structure
+ */
 static void pdc_tasklet_cb(unsigned long data)
 {
 	struct pdc_state *pdcs = (struct pdc_state *)data;
-	bool rx_int;
 
-	rx_int = test_and_clear_bit(PDC_RCVINT_0, &pdcs->intstatus);
-	if (likely(pdcs && rx_int))
-		pdc_receive(pdcs);
+	pdc_receive(pdcs);
 
 	/* reenable interrupts */
 	iowrite32(PDC_INTMASK, pdcs->pdc_reg_vbase + PDC_INTMASK_OFFSET);
@@ -1405,8 +1395,6 @@ static int pdc_interrupts_init(struct pdc_state *pdcs)
 	struct device_node *dn = pdev->dev.of_node;
 	int err;
 
-	pdcs->intstatus = 0;
-
 	/* interrupt configuration */
 	iowrite32(PDC_INTMASK, pdcs->pdc_reg_vbase + PDC_INTMASK_OFFSET);
 	iowrite32(PDC_LAZY_INT, pdcs->pdc_reg_vbase + PDC_RCVLAZY0_OFFSET);
-- 
2.1.0