clocksource/timer-riscv: Refactor riscv_timer_init_dt()

Refactor the timer init function such that few things can be
shared by both DT and ACPI based platforms.

Co-developed-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230515054928.2079268-18-sunilvl@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

drivers/clocksource/timer-riscv.c

@@ -124,61 +124,28 @@ static irqreturn_t riscv_timer_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static int __init riscv_timer_init_dt(struct device_node *n)
+static int __init riscv_timer_init_common(void)
 {
-	int cpuid, error;
+	int error;
-	unsigned long hartid;
-	struct device_node *child;
 	struct irq_domain *domain;
+	struct fwnode_handle *intc_fwnode = riscv_get_intc_hwnode();
 
-	error = riscv_of_processor_hartid(n, &hartid);
+	domain = irq_find_matching_fwnode(intc_fwnode, DOMAIN_BUS_ANY);
-	if (error < 0) {
-		pr_warn("Not valid hartid for node [%pOF] error = [%lu]\n",
-			n, hartid);
-		return error;
-	}
-
-	cpuid = riscv_hartid_to_cpuid(hartid);
-	if (cpuid < 0) {
-		pr_warn("Invalid cpuid for hartid [%lu]\n", hartid);
-		return cpuid;
-	}
-
-	if (cpuid != smp_processor_id())
-		return 0;
-
-	child = of_find_compatible_node(NULL, NULL, "riscv,timer");
-	if (child) {
-		riscv_timer_cannot_wake_cpu = of_property_read_bool(child,
-					"riscv,timer-cannot-wake-cpu");
-		of_node_put(child);
-	}
-
-	domain = NULL;
-	child = of_get_compatible_child(n, "riscv,cpu-intc");
-	if (!child) {
-		pr_err("Failed to find INTC node [%pOF]\n", n);
-		return -ENODEV;
-	}
-	domain = irq_find_host(child);
-	of_node_put(child);
 	if (!domain) {
-		pr_err("Failed to find IRQ domain for node [%pOF]\n", n);
+		pr_err("Failed to find irq_domain for INTC node [%pfwP]\n",
+		       intc_fwnode);
 		return -ENODEV;
 	}
 
 	riscv_clock_event_irq = irq_create_mapping(domain, RV_IRQ_TIMER);
 	if (!riscv_clock_event_irq) {
-		pr_err("Failed to map timer interrupt for node [%pOF]\n", n);
+		pr_err("Failed to map timer interrupt for node [%pfwP]\n", intc_fwnode);
 		return -ENODEV;
 	}
 
-	pr_info("%s: Registering clocksource cpuid [%d] hartid [%lu]\n",
-	       __func__, cpuid, hartid);
 	error = clocksource_register_hz(&riscv_clocksource, riscv_timebase);
 	if (error) {
-		pr_err("RISCV timer register failed [%d] for cpu = [%d]\n",
+		pr_err("RISCV timer registration failed [%d]\n", error);
-		       error, cpuid);
 		return error;
 	}
 
@@ -207,4 +174,36 @@ static int __init riscv_timer_init_dt(struct device_node *n)
 	return error;
 }
 
+static int __init riscv_timer_init_dt(struct device_node *n)
+{
+	int cpuid, error;
+	unsigned long hartid;
+	struct device_node *child;
+
+	error = riscv_of_processor_hartid(n, &hartid);
+	if (error < 0) {
+		pr_warn("Invalid hartid for node [%pOF] error = [%lu]\n",
+			n, hartid);
+		return error;
+	}
+
+	cpuid = riscv_hartid_to_cpuid(hartid);
+	if (cpuid < 0) {
+		pr_warn("Invalid cpuid for hartid [%lu]\n", hartid);
+		return cpuid;
+	}
+
+	if (cpuid != smp_processor_id())
+		return 0;
+
+	child = of_find_compatible_node(NULL, NULL, "riscv,timer");
+	if (child) {
+		riscv_timer_cannot_wake_cpu = of_property_read_bool(child,
+					"riscv,timer-cannot-wake-cpu");
+		of_node_put(child);
+	}
+
+	return riscv_timer_init_common();
+}
+
 TIMER_OF_DECLARE(riscv_timer, "riscv", riscv_timer_init_dt);