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

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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: Nick Hu <nick.hu@sifive.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Cyan Yang <cyan.yang@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Nutty Liu <liujingqi@lanxincomputing.com>
Link: https://patch.msgid.link/20251202-preserve-aplic-imsic-v3-1-1844fbf1fe92@sifive.com
This commit is contained in:
Nick Hu 2025-12-02 14:07:40 +08:00 • committed by Thomas Gleixner
parent 97232dc43e
commit f48b4bd091
1 changed files with 31 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

39
drivers/irqchip/irq-riscv-imsic-early.c
View file

@ -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)