[PATCH v3 1/8] irqchip: Ingenic: Change interrupt handling form cascade to chained_irq.

From: Zhou Yanjie
Date: Mon Jul 15 2019 - 08:10:41 EST


The interrupt handling method is changed from old-style cascade to
chained_irq which is more appropriate. Also, it can process the
corner situation that more than one irq is coming to a single
chip at the same time.

Signed-off-by: Zhou Yanjie <zhouyanjie@xxxxxxxx>
---
drivers/irqchip/irq-ingenic.c | 37 +++++++++++++++++++++++--------------
1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/drivers/irqchip/irq-ingenic.c b/drivers/irqchip/irq-ingenic.c
index f126255..49f7685 100644
--- a/drivers/irqchip/irq-ingenic.c
+++ b/drivers/irqchip/irq-ingenic.c
@@ -1,7 +1,7 @@
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2009-2010, Lars-Peter Clausen <lars@xxxxxxxxxx>
- * JZ4740 platform IRQ support
+ * Ingenic XBurst platform IRQ support
*/

#include <linux/errno.h>
@@ -10,6 +10,7 @@
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
#include <linux/irqchip/ingenic.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
@@ -32,22 +33,34 @@ struct ingenic_intc_data {
#define JZ_REG_INTC_PENDING 0x10
#define CHIP_SIZE 0x20

-static irqreturn_t intc_cascade(int irq, void *data)
+static void ingenic_chained_handle_irq(struct irq_desc *desc)
{
- struct ingenic_intc_data *intc = irq_get_handler_data(irq);
- uint32_t irq_reg;
+ struct ingenic_intc_data *intc = irq_desc_get_handler_data(desc);
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ bool have_irq = false;
+ uint32_t pending;
unsigned i;

+ chained_irq_enter(chip, desc);
for (i = 0; i < intc->num_chips; i++) {
- irq_reg = readl(intc->base + (i * CHIP_SIZE) +
+ pending = readl(intc->base + (i * CHIP_SIZE) +
JZ_REG_INTC_PENDING);
- if (!irq_reg)
+ if (!pending)
continue;

- generic_handle_irq(__fls(irq_reg) + (i * 32) + JZ4740_IRQ_BASE);
+ have_irq = true;
+ while (pending) {
+ int bit = __fls(pending);
+
+ generic_handle_irq(bit + (i * 32) + JZ4740_IRQ_BASE);
+ pending &= ~BIT(bit);
+ }
}

- return IRQ_HANDLED;
+ if (!have_irq)
+ spurious_interrupt();
+
+ chained_irq_exit(chip, desc);
}

static void intc_irq_set_mask(struct irq_chip_generic *gc, uint32_t mask)
@@ -70,11 +83,6 @@ void ingenic_intc_irq_resume(struct irq_data *data)
intc_irq_set_mask(gc, gc->mask_cache);
}

-static struct irqaction intc_cascade_action = {
- .handler = intc_cascade,
- .name = "SoC intc cascade interrupt",
-};
-
static int __init ingenic_intc_of_init(struct device_node *node,
unsigned num_chips)
{
@@ -139,7 +147,8 @@ static int __init ingenic_intc_of_init(struct device_node *node,
if (!domain)
pr_warn("unable to register IRQ domain\n");

- setup_irq(parent_irq, &intc_cascade_action);
+ irq_set_chained_handler_and_data(parent_irq,
+ ingenic_chained_handle_irq, intc);
return 0;

out_unmap_irq:
--
2.7.4