libpayload arm64: Add library helpers

Add library helpers to access standard arm64 registers. This library also
provides functions to directly read/write register based on current el. So, rest
of the code doesnt need to keep checking the el and call appropriate function
based on that.

BUG=chrome-os-partner:31634
BRANCH=None
TEST=Libpayload and depthcharge compile successfully for ryu

Change-Id: Ibc0ca49f158362d4b7ab2045bf0fbd58ada79360
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 2ca6da580cb51b4c23abdaf04fee2785e5780510
Original-Change-Id: I9b63e04aa26a98bbeb34fdef634776d49454ca8d
Original-Signed-off-by: Furquan Shaikh <furquan@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/214575
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Tested-by: Furquan Shaikh <furquan@chromium.org>
Original-Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: http://review.coreboot.org/8784
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

1 files changed, 40 insertions, 0 deletions

diff --git a/payloads/libpayload/arch/arm64/lib/clock.c b/payloads/libpayload/arch/arm64/lib/clock.c
new file mode 100644
index 0000000000..9f06f0828c
--- /dev/null
+++ b/payloads/libpayload/arch/arm64/lib/clock.c
@@ -0,0 +1,40 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2014 Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * clock.c: Functions for accessing clock and timer related registers
+ * Reference: ARM Architecture Reference Manual, ARMv8-A edition
+ */
+
+#include <stdint.h>
+
+#include <arch/lib_helpers.h>
+
+void set_cntfrq(uint32_t freq)
+{
+	__asm__ __volatile__("msr cntfrq_el0, %0" :: "r"(freq));
+}