Commit f48b4bd0 authored by Nick Hu's avatar Nick Hu Committed by Thomas Gleixner
Browse files

irqchip/riscv-imsic: Add a CPU pm notifier to restore the IMSIC on exit 



The IMSIC might be reset when the system enters a low power state, but on
exit nothing restores the registers, which prevents interrupt delivery.

Solve this by registering a CPU power management notifier, which restores
the IMSIC on exit.

Signed-off-by: default avatarNick Hu <nick.hu@sifive.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarYong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: default avatarCyan Yang <cyan.yang@sifive.com>
Reviewed-by: default avatarAnup Patel <anup@brainfault.org>
Reviewed-by: default avatarNutty Liu <liujingqi@lanxincomputing.com>
Link: https://patch.msgid.link/20251202-preserve-aplic-imsic-v3-1-1844fbf1fe92@sifive.com
parent 97232dc4

drivers/irqchip/irq-riscv-imsic-early.c

+31 −8
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#define pr_fmt(fmt) "riscv-imsic: " fmt

#include <linux/acpi.h>

#include <linux/cpu.h>

#include <linux/cpu_pm.h>

#include <linux/export.h>

#include <linux/interrupt.h>

#include <linux/init.h>
@@ -123,14 +124,8 @@ static void imsic_handle_irq(struct irq_desc *desc) 
	chained_irq_exit(chip, desc);

}



static int imsic_starting_cpu(unsigned int cpu)

static void imsic_hw_states_init(void)

{

	/* Mark per-CPU IMSIC state as online */

	imsic_state_online();



	/* Enable per-CPU parent interrupt */

	enable_percpu_irq(imsic_parent_irq, irq_get_trigger_type(imsic_parent_irq));



	/* Setup IPIs */

	imsic_ipi_starting_cpu();
@@ -142,6 +137,18 @@ static int imsic_starting_cpu(unsigned int cpu) 


	/* Enable local interrupt delivery */

	imsic_local_delivery(true);

}



static int imsic_starting_cpu(unsigned int cpu)

{

	/* Mark per-CPU IMSIC state as online */

	imsic_state_online();



	/* Enable per-CPU parent interrupt */

	enable_percpu_irq(imsic_parent_irq, irq_get_trigger_type(imsic_parent_irq));



	/* Initialize the IMSIC registers to enable the interrupt delivery */

	imsic_hw_states_init();



	return 0;

}
@@ -157,6 +164,22 @@ static int imsic_dying_cpu(unsigned int cpu) 
	return 0;

}



static int imsic_pm_notifier(struct notifier_block *self, unsigned long cmd, void *v)

{

	switch (cmd) {

	case CPU_PM_EXIT:

		/* Initialize the IMSIC registers to enable the interrupt delivery */

		imsic_hw_states_init();

		break;

	}



	return NOTIFY_OK;

}



static struct notifier_block imsic_pm_notifier_block = {

	.notifier_call = imsic_pm_notifier,

};



static int __init imsic_early_probe(struct fwnode_handle *fwnode)

{

	struct irq_domain *domain;
@@ -194,7 +217,7 @@ static int __init imsic_early_probe(struct fwnode_handle *fwnode) 
	cpuhp_setup_state(CPUHP_AP_IRQ_RISCV_IMSIC_STARTING, "irqchip/riscv/imsic:starting",

			  imsic_starting_cpu, imsic_dying_cpu);



	return 0;

	return cpu_pm_register_notifier(&imsic_pm_notifier_block);

}



static int __init imsic_early_dt_init(struct device_node *node, struct device_node *parent)