arm64: move from arm_generic to arm_arch_timer

The arch_timer driver supports a superset of the functionality of the
arm_generic driver, and is not tied to a particular arch.

This patch moves arm64 to use the arch_timer driver, gaining additional
functionality in doing so, and removes the (now unused) arm_generic
driver. Timer-related hooks specific to arm64 are moved into
arch/arm64/kernel/time.c.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>

1 files changed, 27 insertions, 2 deletions

diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
index 3b4b7258f492..b0ef18d14c3b 100644
--- a/arch/arm64/kernel/time.c
+++ b/arch/arm64/kernel/time.c
@@ -31,8 +31,9 @@
 #include <linux/syscore_ops.h>
 #include <linux/timer.h>
 #include <linux/irq.h>
+#include <linux/delay.h>
 
-#include <clocksource/arm_generic.h>
+#include <clocksource/arm_arch_timer.h>
 
 #include <asm/thread_info.h>
 #include <asm/stacktrace.h>
@@ -59,7 +60,31 @@ unsigned long profile_pc(struct pt_regs *regs)
 EXPORT_SYMBOL(profile_pc);
 #endif
 
+static u64 sched_clock_mult __read_mostly;
+
+unsigned long long notrace sched_clock(void)
+{
+	return arch_timer_read_counter() * sched_clock_mult;
+}
+
+int read_current_timer(unsigned long *timer_value)
+{
+	*timer_value = arch_timer_read_counter();
+	return 0;
+}
+
 void __init time_init(void)
 {
-	arm_generic_timer_init();
+	u32 arch_timer_rate;
+
+	if (arch_timer_init())
+		panic("Unable to initialise architected timer.\n");
+
+	arch_timer_rate = arch_timer_get_rate();
+
+	/* Cache the sched_clock multiplier to save a divide in the hot path. */
+	sched_clock_mult = NSEC_PER_SEC / arch_timer_rate;
+
+	/* Calibrate the delay loop directly */
+	lpj_fine = arch_timer_rate / HZ;
 }