The interrupt controller shutdown path does not need to save the mask of
enabled interrupts because the next state the system is going to be in
is akin to a cold boot, or a kexec'd kernel. Saving the mask only makes
sense if the software state needs to preserve the hardware state across
a system suspend/resume cycle.
As an optimization, and given that there are systems with dozens of such
interrupt controller, we can save a "slow" memory mapped I/O read in the
shutdown path where no saving/restoring is required.
Reported-by: Tim Ross <tim.ross@xxxxxxxxxxxx>
Signed-off-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>
---
Changes in v2:
- expand the commit message to explain this is an optimiation saving a
slow MMIO read
drivers/irqchip/irq-brcmstb-l2.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/drivers/irqchip/irq-brcmstb-l2.c b/drivers/irqchip/irq-brcmstb-l2.c
index 2b0b3175cea0..c988886917f7 100644
--- a/drivers/irqchip/irq-brcmstb-l2.c
+++ b/drivers/irqchip/irq-brcmstb-l2.c
@@ -118,7 +118,7 @@ static void brcmstb_l2_intc_irq_handle(struct irq_desc *desc)
chained_irq_exit(chip, desc);
}
-static void brcmstb_l2_intc_suspend(struct irq_data *d)
+static void __brcmstb_l2_intc_suspend(struct irq_data *d, bool save)
{
struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
struct irq_chip_type *ct = irq_data_get_chip_type(d);
@@ -127,7 +127,8 @@ static void brcmstb_l2_intc_suspend(struct irq_data *d)
irq_gc_lock_irqsave(gc, flags);
/* Save the current mask */
- b->saved_mask = irq_reg_readl(gc, ct->regs.mask);
+ if (save)
+ b->saved_mask = irq_reg_readl(gc, ct->regs.mask);
if (b->can_wake) {
/* Program the wakeup mask */
@@ -137,6 +138,16 @@ static void brcmstb_l2_intc_suspend(struct irq_data *d)
irq_gc_unlock_irqrestore(gc, flags);
}
+static void brcmstb_l2_intc_shutdown(struct irq_data *d)
+{
+ __brcmstb_l2_intc_suspend(d, false);
+}
+
+static void brcmstb_l2_intc_suspend(struct irq_data *d)
+{
+ __brcmstb_l2_intc_suspend(d, true);
+}
+
static void brcmstb_l2_intc_resume(struct irq_data *d)
{
struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
@@ -252,7 +263,7 @@ static int __init brcmstb_l2_intc_of_init(struct device_node *np,
ct->chip.irq_suspend = brcmstb_l2_intc_suspend;
ct->chip.irq_resume = brcmstb_l2_intc_resume;
- ct->chip.irq_pm_shutdown = brcmstb_l2_intc_suspend;
+ ct->chip.irq_pm_shutdown = brcmstb_l2_intc_shutdown;
if (data->can_wake) {
/* This IRQ chip can wake the system, set all child interrupts
--
2.34.1
