m68knommu: MCF5307 PIT GENERIC_CLOCKEVENTS support
The PIT code has been changed in order to suppport GENERIC_CLOCKEVENTS.
The priority of the PIT clocksource has been decreased in favor of the
DMA timer.
pit_cycles_per_jiffy become a constant (PIT_CYCLES_PER_JIFFY) because it
is known at compile time and does not change afterwards.
Signed-off-by: Benedikt Spranger <b.spranger@linutronix.de>
Signed-off-by: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
diff --git a/arch/m68knommu/platform/coldfire/pit.c b/arch/m68knommu/platform/coldfire/pit.c
index 4290638..c5b9167 100644
--- a/arch/m68knommu/platform/coldfire/pit.c
+++ b/arch/m68knommu/platform/coldfire/pit.c
@@ -18,7 +18,7 @@
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
-#include <linux/clocksource.h>
+#include <linux/clockchips.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/coldfire.h>
@@ -33,22 +33,86 @@
#define FREQ ((MCF_CLK / 2) / 64)
#define TA(a) (MCF_IPSBAR + MCFPIT_BASE1 + (a))
#define INTC0 (MCF_IPSBAR + MCFICM_INTC0)
+#define PIT_CYCLES_PER_JIFFY (FREQ / HZ)
-static u32 pit_cycles_per_jiffy;
static u32 pit_cnt;
+/*
+ * Initialize the PIT timer.
+ *
+ * This is also called after resume to bring the PIT into operation again.
+ */
+
+static void init_cf_pit_timer(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+
+ __raw_writew(MCFPIT_PCSR_DISABLE, TA(MCFPIT_PCSR));
+ __raw_writew(PIT_CYCLES_PER_JIFFY, TA(MCFPIT_PMR));
+ __raw_writew(MCFPIT_PCSR_EN | MCFPIT_PCSR_PIE | \
+ MCFPIT_PCSR_OVW | MCFPIT_PCSR_RLD | \
+ MCFPIT_PCSR_CLK64, TA(MCFPIT_PCSR));
+ break;
+
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ case CLOCK_EVT_MODE_UNUSED:
+
+ __raw_writew(MCFPIT_PCSR_DISABLE, TA(MCFPIT_PCSR));
+ break;
+
+ case CLOCK_EVT_MODE_ONESHOT:
+
+ __raw_writew(MCFPIT_PCSR_DISABLE, TA(MCFPIT_PCSR));
+ __raw_writew(MCFPIT_PCSR_EN | MCFPIT_PCSR_PIE | \
+ MCFPIT_PCSR_OVW | MCFPIT_PCSR_CLK64, \
+ TA(MCFPIT_PCSR));
+ break;
+
+ case CLOCK_EVT_MODE_RESUME:
+ /* Nothing to do here */
+ break;
+ }
+}
+
+/*
+ * Program the next event in oneshot mode
+ *
+ * Delta is given in PIT ticks
+ */
+static int cf_pit_next_event(unsigned long delta,
+ struct clock_event_device *evt)
+{
+ __raw_writew(delta, TA(MCFPIT_PMR));
+ return 0;
+}
+
+struct clock_event_device cf_pit_clockevent = {
+ .name = "pit",
+ .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+ .set_mode = init_cf_pit_timer,
+ .set_next_event = cf_pit_next_event,
+ .shift = 32,
+ .irq = MCFINT_VECBASE + MCFINT_PIT1,
+};
+
+
+
/***************************************************************************/
static irqreturn_t pit_tick(int irq, void *dummy)
{
+ struct clock_event_device *evt = &cf_pit_clockevent;
u16 pcsr;
/* Reset the ColdFire timer */
pcsr = __raw_readw(TA(MCFPIT_PCSR));
__raw_writew(pcsr | MCFPIT_PCSR_PIF, TA(MCFPIT_PCSR));
- pit_cnt += pit_cycles_per_jiffy;
- return arch_timer_interrupt(irq, dummy);
+ pit_cnt += PIT_CYCLES_PER_JIFFY;
+ evt->event_handler(evt);
+ return IRQ_HANDLED;
}
/***************************************************************************/
@@ -72,14 +136,14 @@
cycles = pit_cnt;
local_irq_restore(flags);
- return cycles + pit_cycles_per_jiffy - pcntr;
+ return cycles + PIT_CYCLES_PER_JIFFY - pcntr;
}
/***************************************************************************/
static struct clocksource pit_clk = {
.name = "pit",
- .rating = 250,
+ .rating = 100,
.read = pit_read_clk,
.shift = 20,
.mask = CLOCKSOURCE_MASK(32),
@@ -92,6 +156,14 @@
{
u32 imr;
+ cf_pit_clockevent.cpumask = cpumask_of_cpu(smp_processor_id());
+ cf_pit_clockevent.mult = div_sc(FREQ, NSEC_PER_SEC, 32);
+ cf_pit_clockevent.max_delta_ns =
+ clockevent_delta2ns(0xFFFF, &cf_pit_clockevent);
+ cf_pit_clockevent.min_delta_ns =
+ clockevent_delta2ns(0x3f, &cf_pit_clockevent);
+ clockevents_register_device(&cf_pit_clockevent);
+
setup_irq(MCFINT_VECBASE + MCFINT_PIT1, &pit_irq);
__raw_writeb(ICR_INTRCONF, INTC0 + MCFINTC_ICR0 + MCFINT_PIT1);
@@ -99,13 +171,6 @@
imr &= ~MCFPIT_IMR_IBIT;
__raw_writel(imr, INTC0 + MCFPIT_IMR);
- /* Set up PIT timer 1 as poll clock */
- pit_cycles_per_jiffy = FREQ / HZ;
- __raw_writew(MCFPIT_PCSR_DISABLE, TA(MCFPIT_PCSR));
- __raw_writew(pit_cycles_per_jiffy, TA(MCFPIT_PMR));
- __raw_writew(MCFPIT_PCSR_EN | MCFPIT_PCSR_PIE | MCFPIT_PCSR_OVW |
- MCFPIT_PCSR_RLD | MCFPIT_PCSR_CLK64, TA(MCFPIT_PCSR));
-
pit_clk.mult = clocksource_hz2mult(FREQ, pit_clk.shift);
clocksource_register(&pit_clk);
}