[ARM] pxa: remove periodic mode emulation support (a88264c2) · Commits · 戴 / test

arch/arm/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -345,6 +345,7 @@ config ARCH_PXA
		select GENERIC_GPIO
		select GENERIC_TIME
		select GENERIC_CLOCKEVENTS
		select TICK_ONESHOT
		help
		Support for Intel/Marvell's PXA2xx/PXA3xx processor line.

arch/arm/mach-pxa/time.c

+8 −53

Original line number	Diff line number	Diff line
		@@ -59,55 +59,17 @@ unsigned long long sched_clock(void)
		}


		#define MIN_OSCR_DELTA 16

		static irqreturn_t
		pxa_ost0_interrupt(int irq, void *dev_id)
		{
		int next_match;
		struct clock_event_device *c = dev_id;

		if (c->mode == CLOCK_EVT_MODE_ONESHOT) {
		/* Disarm the compare/match, signal the event. */
		OIER &= ~OIER_E0;
		OSSR = OSSR_M0;
		c->event_handler(c);
		} else if (c->mode == CLOCK_EVT_MODE_PERIODIC) {
		/* Call the event handler as many times as necessary
		* to recover missed events, if any (if we update
		* OSMR0 and OSCR0 is still ahead of us, we've missed
		* the event). As we're dealing with that, re-arm the
		* compare/match for the next event.
		*
		* HACK ALERT:
		*
		* There's a latency between the instruction that
		* writes to OSMR0 and the actual commit to the
		* physical hardware, because the CPU doesn't (have
		* to) run at bus speed, there's a write buffer
		* between the CPU and the bus, etc. etc. So if the
		* target OSCR0 is "very close", to the OSMR0 load
		* value, the update to OSMR0 might not get to the
		* hardware in time and we'll miss that interrupt.
		*
		* To be safe, if the new OSMR0 is "very close" to the
		* target OSCR0 value, we call the event_handler as
		* though the event actually happened. According to
		* Nico's comment in the previous version of this
		* code, experience has shown that 6 OSCR ticks is
		* "very close" but he went with 8. We will use 16,
		* based on the results of testing on PXA270.
		*
		* To be doubly sure, we also tell clkevt via
		* clockevents_register_device() not to ask for
		* anything that might put us "very close".
		*/
		#define MIN_OSCR_DELTA 16
		do {
		OSSR = OSSR_M0;
		next_match = (OSMR0 += LATCH);
		c->event_handler(c);
		} while (((signed long)(next_match - OSCR) <= MIN_OSCR_DELTA)
		&& (c->mode == CLOCK_EVT_MODE_PERIODIC));
		}

		return IRQ_HANDLED;
		}
		@@ -133,14 +95,6 @@ pxa_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *dev)
		unsigned long irqflags;

		switch (mode) {
		case CLOCK_EVT_MODE_PERIODIC:
		raw_local_irq_save(irqflags);
		OSSR = OSSR_M0;
		OIER \|= OIER_E0;
		OSMR0 = OSCR + LATCH;
		raw_local_irq_restore(irqflags);
		break;

		case CLOCK_EVT_MODE_ONESHOT:
		raw_local_irq_save(irqflags);
		OIER &= ~OIER_E0;
		@@ -158,13 +112,14 @@ pxa_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *dev)
		break;

		case CLOCK_EVT_MODE_RESUME:
		case CLOCK_EVT_MODE_PERIODIC:
		break;
		}
		}

		static struct clock_event_device ckevt_pxa_osmr0 = {
		.name = "osmr0",
		.features = CLOCK_EVT_FEAT_PERIODIC \| CLOCK_EVT_FEAT_ONESHOT,
		.features = CLOCK_EVT_FEAT_ONESHOT,
		.shift = 32,
		.rating = 200,
		.cpumask = CPU_MASK_CPU0,

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