feat(fdt): add the ability to supply idle state information

Some platforms require extra firmware to implement CPU_SUSPEND, or only
have working CPU_SUSPEND in certain configurations. On these platforms,
CPU idle states should only be listed in the devicetree when they are
actually available. Add a function BL31 can use to dynamically supply
this idle state information.

Change-Id: I64fcc288303faba8abec4f59efd13a04220d54dc
Signed-off-by: Samuel Holland <samuel@sholland.org>
diff --git a/include/common/fdt_fixup.h b/include/common/fdt_fixup.h
index 7a590b2..c35e9be 100644
--- a/include/common/fdt_fixup.h
+++ b/include/common/fdt_fixup.h
@@ -7,14 +7,29 @@
 #ifndef FDT_FIXUP_H
 #define FDT_FIXUP_H
 
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
 #define INVALID_BASE_ADDR	((uintptr_t)~0UL)
 
+struct psci_cpu_idle_state {
+	const char *name;
+	uint32_t power_state;
+	bool local_timer_stop;
+	uint32_t entry_latency_us;
+	uint32_t exit_latency_us;
+	uint32_t min_residency_us;
+	uint32_t wakeup_latency_us;
+};
+
 int dt_add_psci_node(void *fdt);
 int dt_add_psci_cpu_enable_methods(void *fdt);
 int fdt_add_reserved_memory(void *dtb, const char *node_name,
 			    uintptr_t base, size_t size);
 int fdt_add_cpus_node(void *dtb, unsigned int afflv0,
 		      unsigned int afflv1, unsigned int afflv2);
+int fdt_add_cpu_idle_states(void *dtb, const struct psci_cpu_idle_state *state);
 int fdt_adjust_gic_redist(void *dtb, unsigned int nr_cores, uintptr_t gicr_base,
 			  unsigned int gicr_frame_size);