irqchip/riscv-intc: Fix low-level interrupt handler setup for AIA

Use riscv_intc_aia_irq() as the low-level interrupt handler instead of the
existing riscv_intc_irq() default handler to make demultiplexing work
correctly.

Also print "using AIA" in the INTC boot banner when AIA is available.

Fixes: 3c46fc5b ("irqchip/riscv-intc: Add support for RISC-V AIA")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240226040746.1396416-2-apatel@ventanamicro.com

drivers/irqchip/irq-riscv-intc.c

@@ -183,7 +183,10 @@ static int __init riscv_intc_init_common(struct fwnode_handle *fn, struct irq_ch
 		return -ENXIO;
 	}
 
-	rc = set_handle_irq(&riscv_intc_irq);
+	if (riscv_isa_extension_available(NULL, SxAIA))
+		rc = set_handle_irq(&riscv_intc_aia_irq);
+	else
+		rc = set_handle_irq(&riscv_intc_irq);
 	if (rc) {
 		pr_err("failed to set irq handler\n");
 		return rc;
@@ -191,8 +194,9 @@ static int __init riscv_intc_init_common(struct fwnode_handle *fn, struct irq_ch
 
 	riscv_set_intc_hwnode_fn(riscv_intc_hwnode);
 
-	pr_info("%d local interrupts mapped\n",
-		riscv_isa_extension_available(NULL, SxAIA) ? 64 : riscv_intc_nr_irqs);
+	pr_info("%d local interrupts mapped%s\n",
+		riscv_isa_extension_available(NULL, SxAIA) ? 64 : riscv_intc_nr_irqs,
+		riscv_isa_extension_available(NULL, SxAIA) ? " using AIA" : "");
 	if (riscv_intc_custom_nr_irqs)
 		pr_info("%d custom local interrupts mapped\n", riscv_intc_custom_nr_irqs);