We add empty irq_eoi() in RISC-V INTC driver for child irqchip
drivers (such as PLIC, SBI IPI, CLINT, APLIC, IMSIC, etc) which
implement chained handlers for parent per-HART local interrupts.
This hels us avoid unnecessary mask/unmask of per-HART local
interrupts at the time of handling interrupts.
Signed-off-by: Anup Patel <[email protected]>
---
drivers/irqchip/irq-riscv-intc.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
index 784d25645704..f229e3e66387 100644
--- a/drivers/irqchip/irq-riscv-intc.c
+++ b/drivers/irqchip/irq-riscv-intc.c
@@ -46,10 +46,27 @@ static void riscv_intc_irq_unmask(struct irq_data *d)
csr_set(CSR_IE, BIT(d->hwirq));
}
+static void riscv_intc_irq_eoi(struct irq_data *d)
+{
+ /*
+ * The RISC-V INTC driver uses handle_percpu_devid_irq() flow
+ * for the per-HART local interrupts and child irqchip drivers
+ * (such as PLIC, SBI IPI, CLINT, APLIC, IMSIC, etc) implement
+ * chained handlers for the per-HART local interrupts.
+ *
+ * In the absence of irq_eoi(), the chained_irq_enter() and
+ * chained_irq_exit() functions (used by child irqchip drivers)
+ * will do unnecessary mask/unmask of per-HART local interrupts
+ * at the time of handling interrupts. To avoid this, we provide
+ * an empty irq_eoi() callback for RISC-V INTC irqchip.
+ */
+}
+
static struct irq_chip riscv_intc_chip = {
.name = "RISC-V INTC",
.irq_mask = riscv_intc_irq_mask,
.irq_unmask = riscv_intc_irq_unmask,
+ .irq_eoi = riscv_intc_irq_eoi,
};
static int riscv_intc_domain_map(struct irq_domain *d, unsigned int irq,
--
2.34.1