drivers: clocksource: add support for ARM architected timer event stream

	bool

	select CLKSRC_OF if OF

config ARM_ARCH_TIMER_EVTSTREAM

	bool "Support for ARM architected timer event stream generation"

	default y if ARM_ARCH_TIMER

	help

	  This option enables support for event stream generation based on

	  the ARM architected timer. It is used for waking up CPUs executing

	  the wfe instruction at a frequency represented as a power-of-2

	  divisor of the clock rate.

	  The main use of the event stream is wfe-based timeouts of userspace

	  locking implementations. It might also be useful for imposing timeout

	  on wfe to safeguard against any programming errors in case an expected

	  event is not generated.

	  This must be disabled for hardware validation purposes to detect any

	  hardware anomalies of missing events.

config ARM_GLOBAL_TIMER

	bool

	select CLKSRC_OF if OF

	clockevents_config_and_register(clk, arch_timer_rate, 0xf, 0x7fffffff);

}

static void arch_timer_configure_evtstream(void)

{

	int evt_stream_div, pos;

	/* Find the closest power of two to the divisor */

	evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ;

	pos = fls(evt_stream_div);

	if (pos > 1 && !(evt_stream_div & (1 << (pos - 2))))

		pos--;

	/* enable event stream */

	arch_timer_evtstrm_enable(min(pos, 15));

}

static int arch_timer_setup(struct clock_event_device *clk)

{

	__arch_timer_setup(ARCH_CP15_TIMER, clk);

	}

	arch_counter_set_user_access();

	if (IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM))

		arch_timer_configure_evtstream();

	return 0;

}

#define ARCH_TIMER_USR_VT_ACCESS_EN	(1 << 8) /* virtual timer registers */

#define ARCH_TIMER_USR_PT_ACCESS_EN	(1 << 9) /* physical timer registers */

#define ARCH_TIMER_EVT_STREAM_FREQ	10000	/* 100us */

#ifdef CONFIG_ARM_ARCH_TIMER

extern u32 arch_timer_get_rate(void);