fconf: Extract Timer clock freq from HW_CONFIG dtb

Extract Timer clock frequency from the timer node in
HW_CONFIG dtb. The first timer is a per-core architected timer attached
to a GIC to deliver its per-processor interrupts via PPIs.

Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>
Change-Id: I2f4b27c48e4c79208dab9f03c768d9221ba6ca86

plat/arm/board/fvp/fconf/fconf_hw_config_getter.c

@@ -14,6 +14,7 @@
 struct gicv3_config_t gicv3_config;
 struct hw_topology_t soc_topology;
 struct uart_serial_config_t uart_serial_config;
+struct cpu_timer_t cpu_timer;
 
 #define ILLEGAL_ADDR	ULL(~0)
 
@@ -260,9 +261,36 @@ int fconf_populate_uart_config(uintptr_t config)
 
 	VERBOSE("FCONF: UART serial device clk frequency: %x\n",
 		uart_serial_config.uart_clk);
+
+	return 0;
+}
+
+int fconf_populate_cpu_timer(uintptr_t config)
+{
+	int err, node;
+
+	/* Necessary to work with libfdt APIs */
+	const void *hw_config_dtb = (const void *)config;
+
+	/* Find the node offset point to "arm,armv8-timer" compatible property,
+	 * a per-core architected timer attached to a GIC to deliver its per-processor
+	 * interrupts via PPIs */
+	node = fdt_node_offset_by_compatible(hw_config_dtb, -1, "arm,armv8-timer");
+	if (node < 0) {
+		ERROR("FCONF: Unrecognized hardware configuration dtb (%d)\n", node);
+		return node;
+	}
+
+	/* Locate the cell holding the clock-frequency, an optional field */
+	err = fdt_read_uint32(hw_config_dtb, node, "clock-frequency", &cpu_timer.clock_freq);
+	if (err < 0) {
+		WARN("FCONF failed to read clock-frequency property\n");
+	}
+
 	return 0;
 }
 
 FCONF_REGISTER_POPULATOR(HW_CONFIG, gicv3_config, fconf_populate_gicv3_config);
 FCONF_REGISTER_POPULATOR(HW_CONFIG, topology, fconf_populate_topology);
 FCONF_REGISTER_POPULATOR(HW_CONFIG, uart_config, fconf_populate_uart_config);
+FCONF_REGISTER_POPULATOR(HW_CONFIG, cpu_timer, fconf_populate_cpu_timer);

plat/arm/board/fvp/include/fconf_hw_config_getter.h

@@ -11,10 +11,9 @@
 
 /* Hardware Config related getter */
 #define hw_config__gicv3_config_getter(prop) gicv3_config.prop
-
 #define hw_config__topology_getter(prop) soc_topology.prop
-
 #define hw_config__uart_serial_config_getter(prop) uart_serial_config.prop
+#define hw_config__cpu_timer_getter(prop) cpu_timer.prop
 
 struct gicv3_config_t {
 	uint64_t gicd_base;
@@ -33,12 +32,17 @@ struct uart_serial_config_t {
 	uint32_t uart_clk;
 };
 
+struct cpu_timer_t {
+	uint32_t clock_freq;
+};
+
 int fconf_populate_gicv3_config(uintptr_t config);
 int fconf_populate_topology(uintptr_t config);
 int fconf_populate_uart_config(uintptr_t config);
+int fconf_populate_cpu_timer(uintptr_t config);
 
 extern struct gicv3_config_t gicv3_config;
 extern struct hw_topology_t soc_topology;
 extern struct uart_serial_config_t uart_serial_config;
-
+extern struct cpu_timer_t cpu_timer;
 #endif /* FCONF_HW_CONFIG_GETTER_H */