irqchip/versatile-fpga: Handle chained IRQs properly

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

diff --git a/drivers/irqchip/irq-versatile-fpga.c b/drivers/irqchip/irq-versatile-fpga.c
index 928858dada756255cbb4c27c2ae0c191373e6513..70e2cfff8175f915028595021ed1cb4d3e662e72 100644 (file)
--- 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);
 }
 
 /*