From f48b4bd0915bf61ac12b8c65c7939ebd03bc8abf Mon Sep 17 00:00:00 2001 From: Nick Hu Date: Tue, 2 Dec 2025 14:07:40 +0800 Subject: [PATCH] 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: Nick Hu Signed-off-by: Thomas Gleixner Reviewed-by: Yong-Xuan Wang Reviewed-by: Cyan Yang Reviewed-by: Anup Patel Reviewed-by: Nutty Liu Link: https://patch.msgid.link/20251202-preserve-aplic-imsic-v3-1-1844fbf1fe92@sifive.com --- drivers/irqchip/irq-riscv-imsic-early.c | 39 ++++++++++++++++++++----- 1 file changed, 31 insertions(+), 8 deletions(-) diff --git a/drivers/irqchip/irq-riscv-imsic-early.c b/drivers/irqchip/irq-riscv-imsic-early.c index 6bac67cc0b6d9..ba903fa689bd5 100644 --- a/drivers/irqchip/irq-riscv-imsic-early.c +++ b/drivers/irqchip/irq-riscv-imsic-early.c @@ -7,6 +7,7 @@ #define pr_fmt(fmt) "riscv-imsic: " fmt #include #include +#include #include #include #include @@ -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) -- 2.47.3