arm64: Use cpu timer for timekeeping.

grub-core/Makefile.core.def

@@ -213,7 +213,7 @@ kernel = {
   arm_efi = kern/arm/efi/init.c;
   arm_efi = kern/arm/efi/misc.c;
 
-  arm64_efi = kern/arm/efi/init.c;
+  arm64_efi = kern/arm64/efi/init.c;
 
   i386_pc = kern/i386/pc/init.c;
   i386_pc = kern/i386/pc/mmap.c;

grub-core/kern/arm64/efi/init.c

@@ -0,0 +1,60 @@
+/* init.c - initialize an arm-based EFI system */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2013 Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/env.h>
+#include <grub/kernel.h>
+#include <grub/misc.h>
+#include <grub/mm.h>
+#include <grub/time.h>
+#include <grub/efi/efi.h>
+#include <grub/loader.h>
+
+static grub_uint64_t timer_frequency_in_khz;
+
+static grub_uint64_t
+grub_efi_get_time_ms (void)
+{
+  grub_uint64_t tmr;
+  asm volatile("mrs %0,   cntvct_el0" : "=r" (tmr));
+
+  return tmr / timer_frequency_in_khz;
+}
+
+
+void
+grub_machine_init (void)
+{
+  grub_uint64_t timer_frequency;
+
+  grub_efi_init ();
+
+  asm volatile("mrs %0,   cntfrq_el0" : "=r" (timer_frequency));
+  timer_frequency_in_khz = timer_frequency / 1000;
+
+  grub_install_get_time_ms (grub_efi_get_time_ms);
+}
+
+void
+grub_machine_fini (int flags)
+{
+  if (!(flags & GRUB_LOADER_FLAG_NORETURN))
+    return;
+
+  grub_efi_fini ();
+}