linux-kernel - [PATCH v2] irqchip: gic-v3: Handle failure case of CPU enters low power state

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Message-ID: <20241220093907.2747601-1-quic_ylal@quicinc.com>
Date: Fri, 20 Dec 2024 15:09:07 +0530
From: Yogesh Lal <quic_ylal@...cinc.com>
To: Marc Zyngier <maz@...nel.org>, Thomas Gleixner <tglx@...utronix.de>
CC: <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>, Yogesh Lal <quic_ylal@...cinc.com>
Subject: [PATCH v2] irqchip: gic-v3: Handle failure case of CPU enters low power state

Adding a new condition in gic_cpu_pm_notifier to address instances
where the CPU fails to enter low power mode (CPU_PM_ENTER_FAILED).
The CPU_PM framework signals CPU_PM_ENTER_FAILED upon such failures.

When the CPU attempts to enter low power mode, it disables the
redistributor and Group 1 interrupts and reinitializes the system
registers upon wakeup.

In case of failure while entering low power mode, it is necessary
to re-enable the redistributor and Group 1 interrupts to restore
normal operation.

Signed-off-by: Yogesh Lal <quic_ylal@...cinc.com>
---
 drivers/irqchip/irq-gic-v3.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

---
Changes in V2:

* Updating the commit message
* Link to V1: https://lore.kernel.org/all/1671734140-15935-1-git-send-email-quic_ylal@quicinc.com/
---

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index c19083bfb943..2a99ca5c3f1d 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -1495,7 +1495,7 @@ static int gic_retrigger(struct irq_data *data)
 static int gic_cpu_pm_notifier(struct notifier_block *self,
 			       unsigned long cmd, void *v)
 {
-	if (cmd == CPU_PM_EXIT) {
+	if (cmd == CPU_PM_EXIT || cmd == CPU_PM_ENTER_FAILED) {
 		if (gic_dist_security_disabled())
 			gic_enable_redist(true);
 		gic_cpu_sys_reg_init();
-- 
2.34.1