linux-kernel - [PATCH v3 3/6] irqchip/realtek-rtl: clear all pending interrupts

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Date:   Sun,  9 Jan 2022 15:54:34 +0100
From:   Sander Vanheule <sander@...nheule.net>
To:     linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Marc Zyngier <maz@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Birger Koblitz <mail@...ger-koblitz.de>,
        Bert Vermeulen <bert@...t.com>,
        John Crispin <john@...ozen.org>,
        Sander Vanheule <sander@...nheule.net>
Subject: [PATCH v3 3/6] irqchip/realtek-rtl: clear all pending interrupts

Instead of only servicing the lowest pending interrupt line, make sure
all pending SoC interrupts are serviced before exiting the chained
handler. This adds a small overhead if only one interrupt is pending,
but should prevent rapid re-triggering of the handler.

Signed-off-by: Sander Vanheule <sander@...nheule.net>
---
 drivers/irqchip/irq-realtek-rtl.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-realtek-rtl.c b/drivers/irqchip/irq-realtek-rtl.c
index 568614edd88f..50a56820c99b 100644
--- a/drivers/irqchip/irq-realtek-rtl.c
+++ b/drivers/irqchip/irq-realtek-rtl.c
@@ -76,16 +76,20 @@ static void realtek_irq_dispatch(struct irq_desc *desc)
 {
 	struct irq_chip *chip = irq_desc_get_chip(desc);
 	struct irq_domain *domain;
-	unsigned int pending;
+	unsigned long pending;
+	unsigned int soc_int;
 
 	chained_irq_enter(chip, desc);
 	pending = readl(REG(RTL_ICTL_GIMR)) & readl(REG(RTL_ICTL_GISR));
+
 	if (unlikely(!pending)) {
 		spurious_interrupt();
 		goto out;
 	}
+
 	domain = irq_desc_get_handler_data(desc);
-	generic_handle_domain_irq(domain, __ffs(pending));
+	for_each_set_bit(soc_int, &pending, 32)
+		generic_handle_domain_irq(domain, soc_int);
 
 out:
 	chained_irq_exit(chip, desc);
-- 
2.33.1