[PATCH v2 09/12] irqchip/armada-370-xp: Fix reenabling last per-CPU interrupt

[Marek Behún]

The number of per-CPU interrupts is 29 (0 to 28). This is described by
the constant MPIC_MAX_PER_CPU_IRQS, set to 28 (the maximum per-CPU
interrupt).

Commit 0fa4ce746d1d ("irqchip/armada-370-xp: Re-enable per-CPU
interrupts at resume time") used the constant incorrectly in the
for-loop, it used the operator < instead of <=, causing it to iterate
only the first 28 interrupts (0 to 27), ignoring the last, 28th,
per-CPU interrupt.

To avoid this kind of confusions, fix this issue by renaming the constant
to MPIC_PER_CPU_IRQS_NR and set it to 29, the number of per-CPU IRQs.
Update its use in mpic_is_percpu_irq() accordingly.

Cc: <stable+noautosel at kernel.org> # The 29th interrupt is not used in any device-tree
Fixes: 0fa4ce746d1d ("irqchip/armada-370-xp: Re-enable per-CPU interrupts at resume time")
Signed-off-by: Marek Behún <kabel at kernel.org>
---
Thomas, I have added the stable+noautosel Cc so that this patch won't be
autoselected for stable releases, as described in
Documentation/process/stable-kernel-rules.rst. This way I can keep the
Fixes tag.
---
 drivers/irqchip/irq-armada-370-xp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-armada-370-xp.c b/drivers/irqchip/irq-armada-370-xp.c
index f8658a232f21..83afc3a27812 100644
--- a/drivers/irqchip/irq-armada-370-xp.c
+++ b/drivers/irqchip/irq-armada-370-xp.c
@@ -133,7 +133,7 @@
 #define MPIC_INT_FABRIC_MASK			0x54
 #define MPIC_INT_CAUSE_PERF(cpu)		BIT(cpu)
 
-#define MPIC_MAX_PER_CPU_IRQS			28
+#define MPIC_PER_CPU_IRQS_NR			29
 
 /* IPI and MSI interrupt definitions for IPI platforms */
 #define IPI_DOORBELL_NR				8
@@ -202,7 +202,7 @@ static inline bool mpic_is_ipi_available(struct mpic *mpic)
 
 static inline bool mpic_is_percpu_irq(irq_hw_number_t hwirq)
 {
-	return hwirq <= MPIC_MAX_PER_CPU_IRQS;
+	return hwirq < MPIC_PER_CPU_IRQS_NR;
 }
 
 /*
@@ -545,7 +545,7 @@ static void mpic_smp_cpu_init(struct mpic *mpic)
 static void mpic_reenable_percpu(struct mpic *mpic)
 {
 	/* Re-enable per-CPU interrupts that were enabled before suspend */
-	for (irq_hw_number_t i = 0; i < MPIC_MAX_PER_CPU_IRQS; i++) {
+	for (irq_hw_number_t i = 0; i < MPIC_PER_CPU_IRQS_NR; i++) {
 		unsigned int virq = irq_linear_revmap(mpic->domain, i);
 		struct irq_data *d;
 
-- 
2.44.2