arm: arch_timer: move core to drivers/clocksource

The core functionality of the arch_timer driver is not directly tied to
anything under arch/arm, and can be split out.

This patch factors out the core of the arch_timer driver, so it can be
shared with other architectures. A couple of functions are added so
that architecture-specific code can interact with the driver without
needing to touch its internals.

The ARM_ARCH_TIMER config variable is moved out to
drivers/clocksource/Kconfig, existing uses in arch/arm are replaced with
HAVE_ARM_ARCH_TIMER, which selects it.

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>

arch/arm/Kconfig

@@ -1572,9 +1572,10 @@ config HAVE_ARM_SCU
 	help
 	  This option enables support for the ARM system coherency unit
 
-config ARM_ARCH_TIMER
+config HAVE_ARM_ARCH_TIMER
 	bool "Architected timer support"
 	depends on CPU_V7
+	select ARM_ARCH_TIMER
 	help
 	  This option enables support for the ARM architected timer
 

arch/arm/include/asm/arch_timer.h

@@ -4,22 +4,14 @@
 #include <asm/barrier.h>
 #include <asm/errno.h>
 #include <linux/clocksource.h>
+#include <linux/init.h>
 #include <linux/types.h>
 
+#include <clocksource/arm_arch_timer.h>
+
 #ifdef CONFIG_ARM_ARCH_TIMER
 int arch_timer_of_register(void);
 int arch_timer_sched_clock_init(void);
-struct timecounter *arch_timer_get_timecounter(void);
-
-#define ARCH_TIMER_CTRL_ENABLE		(1 << 0)
-#define ARCH_TIMER_CTRL_IT_MASK		(1 << 1)
-#define ARCH_TIMER_CTRL_IT_STAT		(1 << 2)
-
-#define ARCH_TIMER_REG_CTRL		0
-#define ARCH_TIMER_REG_TVAL		1
-
-#define ARCH_TIMER_PHYS_ACCESS		0
-#define ARCH_TIMER_VIRT_ACCESS		1
 
 /*
  * These register accessors are marked inline so the compiler can
@@ -128,11 +120,6 @@ static inline int arch_timer_sched_clock_init(void)
 {
 	return -ENXIO;
 }
-
-static inline struct timecounter *arch_timer_get_timecounter(void)
-{
-	return NULL;
-}
 #endif
 
 #endif