[PATCH AUTOSEL 5.6 32/68] irqchip/versatile-fpga: Handle chained IRQs properly

Sasha Levin
2020-04-10T04:02:11Z

From: Sungbo Eo <mans0n@gorani.run>

[ Upstream commit 486562da598c59e9f835b551d7cf19507de2d681 ]

Enclose the chained handler with chained_irq_{enter,exit}(), so that the
muxed interrupts get properly acked.

This patch also fixes a reboot bug on OX820 SoC, where the jiffies timer
interrupt is never acked. The kernel waits a clock tick forever in
calibrate_delay_converge(), which leads to a boot hang.

Fixes: c41b16f8c9d9 ("ARM: integrator/versatile: consolidate FPGA IRQ handling code")
Signed-off-by: Sungbo Eo <mans0n@gorani.run>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200319023448.1479701-1-mans0n@gorani.run
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/irqchip/irq-versatile-fpga.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-versatile-fpga.c b/drivers/irqchip/irq-versatile-fpga.c
index 928858dada756..70e2cfff8175f 100644
--- a/drivers/irqchip/irq-versatile-fpga.c
+++ b/drivers/irqchip/irq-versatile-fpga.c
@@ -6,6 +6,7 @@
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
#include <linux/irqchip/versatile-fpga.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
@@ -68,12 +69,16 @@ static void fpga_irq_unmask(struct irq_data *d)

static void fpga_irq_handle(struct irq_desc *desc)
{
+ struct irq_chip *chip = irq_desc_get_chip(desc);
struct fpga_irq_data *f = irq_desc_get_handler_data(desc);
- u32 status = readl(f->base + IRQ_STATUS);
+ u32 status;
+
+ chained_irq_enter(chip, desc);

+ status = readl(f->base + IRQ_STATUS);
if (status == 0) {
do_bad_IRQ(desc);
- return;
+ goto out;
}

do {
@@ -82,6 +87,9 @@ static void fpga_irq_handle(struct irq_desc *desc)
status &= ~(1 << irq);
generic_handle_irq(irq_find_mapping(f->domain, irq));
} while (status);
+
+out:
+ chained_irq_exit(chip, desc);
}

/*
--
2.20.1