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From bda65817167cce5294e1d84670f36815262ed550 Mon Sep 17 00:00:00 2001
From: Russell King <rmk@dyn-67.arm.linux.org.uk>
Date: Sun, 3 Feb 2008 21:58:12 +0300
Subject: [PATCH 19/64] pxa: remove periodic mode emulation support
Apparantly, the generic time subsystem can accurately emulate periodic
mode via the one-shot support code, so we don't need our own periodic
emulation code anymore. Just ensure that we build support for one shot
into the generic time subsystem.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
arch/arm/Kconfig | 1 +
arch/arm/mach-pxa/time.c | 61 ++++++----------------------------------------
2 files changed, 9 insertions(+), 53 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index a04f507..1be7182 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -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.
diff --git a/arch/arm/mach-pxa/time.c b/arch/arm/mach-pxa/time.c
index fbfa192..3c4abbf 100644
--- a/arch/arm/mach-pxa/time.c
+++ b/arch/arm/mach-pxa/time.c
@@ -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));
- }
+ /* Disarm the compare/match, signal the event. */
+ OIER &= ~OIER_E0;
+ OSSR = OSSR_M0;
+ c->event_handler(c);
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,
--
1.5.3.8
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