lib: utils: Add simple FDT timer framework

We add simple timer framework which will select and use timer driver
based on details in FDT passed by previous booting stage.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

include/sbi_utils/timer/fdt_timer.h

@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *   Anup Patel <anup.patel@wdc.com>
+ */
+
+#ifndef __FDT_TIMER_H__
+#define __FDT_TIMER_H__
+
+#include <sbi/sbi_types.h>
+
+struct fdt_timer {
+	const struct fdt_match *match_table;
+	int (*cold_init)(void *fdt, int nodeoff, const struct fdt_match *match);
+	int (*warm_init)(void);
+	void (*exit)(void);
+	u64 (*value)(void);
+	void (*event_stop)(void);
+	void (*event_start)(u64 next_event);
+};
+
+u64 fdt_timer_value(void);
+
+void fdt_timer_event_stop(void);
+
+void fdt_timer_event_start(u64 next_event);
+
+void fdt_timer_exit(void);
+
+int fdt_timer_init(bool cold_boot);
+
+#endif