summaryrefslogtreecommitdiffstats
path: root/arch/m68k/coldfire/pit.c
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /arch/m68k/coldfire/pit.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/m68k/coldfire/pit.c')
-rw-r--r--arch/m68k/coldfire/pit.c162
1 files changed, 162 insertions, 0 deletions
diff --git a/arch/m68k/coldfire/pit.c b/arch/m68k/coldfire/pit.c
new file mode 100644
index 0000000000..855d0af470
--- /dev/null
+++ b/arch/m68k/coldfire/pit.c
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0
+/***************************************************************************/
+
+/*
+ * pit.c -- Freescale ColdFire PIT timer. Currently this type of
+ * hardware timer only exists in the Freescale ColdFire
+ * 5270/5271, 5282 and 5208 CPUs. No doubt newer ColdFire
+ * family members will probably use it too.
+ *
+ * Copyright (C) 1999-2008, Greg Ungerer (gerg@snapgear.com)
+ * Copyright (C) 2001-2004, SnapGear Inc. (www.snapgear.com)
+ */
+
+/***************************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/param.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/clockchips.h>
+#include <asm/machdep.h>
+#include <asm/io.h>
+#include <asm/coldfire.h>
+#include <asm/mcfpit.h>
+#include <asm/mcfsim.h>
+
+/***************************************************************************/
+
+/*
+ * By default use timer1 as the system clock timer.
+ */
+#define FREQ ((MCF_CLK / 2) / 64)
+#define TA(a) (MCFPIT_BASE1 + (a))
+#define PIT_CYCLES_PER_JIFFY (FREQ / HZ)
+
+static u32 pit_cnt;
+
+/*
+ * Initialize the PIT timer.
+ *
+ * This is also called after resume to bring the PIT into operation again.
+ */
+
+static int cf_pit_set_periodic(struct clock_event_device *evt)
+{
+ __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));
+ return 0;
+}
+
+static int cf_pit_set_oneshot(struct clock_event_device *evt)
+{
+ __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));
+ return 0;
+}
+
+static int cf_pit_shutdown(struct clock_event_device *evt)
+{
+ __raw_writew(MCFPIT_PCSR_DISABLE, TA(MCFPIT_PCSR));
+ return 0;
+}
+
+/*
+ * 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_state_shutdown = cf_pit_shutdown,
+ .set_state_periodic = cf_pit_set_periodic,
+ .set_state_oneshot = cf_pit_set_oneshot,
+ .set_next_event = cf_pit_next_event,
+ .shift = 32,
+ .irq = MCF_IRQ_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;
+ evt->event_handler(evt);
+ return IRQ_HANDLED;
+}
+
+/***************************************************************************/
+
+static u64 pit_read_clk(struct clocksource *cs)
+{
+ unsigned long flags;
+ u32 cycles;
+ u16 pcntr;
+
+ local_irq_save(flags);
+ pcntr = __raw_readw(TA(MCFPIT_PCNTR));
+ cycles = pit_cnt;
+ local_irq_restore(flags);
+
+ return cycles + PIT_CYCLES_PER_JIFFY - pcntr;
+}
+
+/***************************************************************************/
+
+static struct clocksource pit_clk = {
+ .name = "pit",
+ .rating = 100,
+ .read = pit_read_clk,
+ .mask = CLOCKSOURCE_MASK(32),
+};
+
+/***************************************************************************/
+
+void hw_timer_init(void)
+{
+ int ret;
+
+ cf_pit_clockevent.cpumask = cpumask_of(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.max_delta_ticks = 0xFFFF;
+ cf_pit_clockevent.min_delta_ns =
+ clockevent_delta2ns(0x3f, &cf_pit_clockevent);
+ cf_pit_clockevent.min_delta_ticks = 0x3f;
+ clockevents_register_device(&cf_pit_clockevent);
+
+ ret = request_irq(MCF_IRQ_PIT1, pit_tick, IRQF_TIMER, "timer", NULL);
+ if (ret) {
+ pr_err("Failed to request irq %d (timer): %pe\n", MCF_IRQ_PIT1,
+ ERR_PTR(ret));
+ }
+
+ clocksource_register_hz(&pit_clk, FREQ);
+}
+
+/***************************************************************************/