Re: [PATCH] irqchip/irq-brcmstb-l2: Avoid saving mask on shutdown

From: Florian Fainelli
Date: Mon Apr 22 2024 - 18:27:09 EST


On 4/22/24 14:29, Thomas Gleixner wrote:
On Tue, Apr 16 2024 at 12:43, Florian Fainelli wrote:
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.

Sure, but

Reported-by: Tim Ross <tim.ross@xxxxxxxxxxxx>
Signed-off-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>
---
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);

what's the conditional actually buying you except more complex code?

Not much this is an optimization that is simple to carry out. There can be dozens of such L2 interrupt controllers in a given system and the MMIO accesses start adding up eventually.
--
Florian