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authorMarc Zyngier <marc.zyngier@arm.com>2012-03-05 11:49:30 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2012-09-17 13:42:20 +0100
commit985c0679dfa459a1deed31b999b26e4420786874 (patch)
tree517dff1174d62e7ac6ec6c2f8a993dd6fe830c04 /arch/arm64/kernel
parent257cb251925f854da435cbf79b140984413871ac (diff)
arm64: Generic timers support
This patch adds support for the ARM generic timers with A64 instructions for accessing the timer registers. It uses the physical counter as the clock source and the virtual counter as sched_clock. The timer frequency can be specified via DT or read from the CNTFRQ_EL0 register. The physical counter is also accessible from user space allowing fast gettimeofday() implementation. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Olof Johansson <olof@lixom.net> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'arch/arm64/kernel')
-rw-r--r--arch/arm64/kernel/time.c65
1 files changed, 65 insertions, 0 deletions
diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
new file mode 100644
index 000000000000..3b4b7258f492
--- /dev/null
+++ b/arch/arm64/kernel/time.c
@@ -0,0 +1,65 @@
+/*
+ * Based on arch/arm/kernel/time.c
+ *
+ * Copyright (C) 1991, 1992, 1995 Linus Torvalds
+ * Modifications for ARM (C) 1994-2001 Russell King
+ * Copyright (C) 2012 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/timex.h>
+#include <linux/errno.h>
+#include <linux/profile.h>
+#include <linux/syscore_ops.h>
+#include <linux/timer.h>
+#include <linux/irq.h>
+
+#include <clocksource/arm_generic.h>
+
+#include <asm/thread_info.h>
+#include <asm/stacktrace.h>
+
+#ifdef CONFIG_SMP
+unsigned long profile_pc(struct pt_regs *regs)
+{
+ struct stackframe frame;
+
+ if (!in_lock_functions(regs->pc))
+ return regs->pc;
+
+ frame.fp = regs->regs[29];
+ frame.sp = regs->sp;
+ frame.pc = regs->pc;
+ do {
+ int ret = unwind_frame(&frame);
+ if (ret < 0)
+ return 0;
+ } while (in_lock_functions(frame.pc));
+
+ return frame.pc;
+}
+EXPORT_SYMBOL(profile_pc);
+#endif
+
+void __init time_init(void)
+{
+ arm_generic_timer_init();
+}