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authorAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
committerAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
commitb4b6116a13633898cf868f2f103c96a90c4c20f8 (patch)
tree93d1b7e2cfcdf473d8d4ff3ad141fa864f8491f6 /arch/hexagon/kernel/time.c
parentedd4be777c953e5faafc80d091d3084b4343f5d3 (diff)
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fedora kernel: d9aad82f3319f3cfd1aebc01234254ef0c37ad84v3.3.2-1
Signed-off-by: Anton Arapov <anton@redhat.com>
Diffstat (limited to 'arch/hexagon/kernel/time.c')
-rw-r--r--arch/hexagon/kernel/time.c250
1 files changed, 250 insertions, 0 deletions
diff --git a/arch/hexagon/kernel/time.c b/arch/hexagon/kernel/time.c
new file mode 100644
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+++ b/arch/hexagon/kernel/time.c
@@ -0,0 +1,250 @@
+/*
+ * Time related functions for Hexagon architecture
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/init.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/interrupt.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/ioport.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#include <asm/timer-regs.h>
+#include <asm/hexagon_vm.h>
+
+/*
+ * For the clocksource we need:
+ * pcycle frequency (600MHz)
+ * For the loops_per_jiffy we need:
+ * thread/cpu frequency (100MHz)
+ * And for the timer, we need:
+ * sleep clock rate
+ */
+
+cycles_t pcycle_freq_mhz;
+cycles_t thread_freq_mhz;
+cycles_t sleep_clk_freq;
+
+static struct resource rtos_timer_resources[] = {
+ {
+ .start = RTOS_TIMER_REGS_ADDR,
+ .end = RTOS_TIMER_REGS_ADDR+PAGE_SIZE-1,
+ .flags = IORESOURCE_MEM,
+ },
+};
+
+static struct platform_device rtos_timer_device = {
+ .name = "rtos_timer",
+ .id = -1,
+ .num_resources = ARRAY_SIZE(rtos_timer_resources),
+ .resource = rtos_timer_resources,
+};
+
+/* A lot of this stuff should move into a platform specific section. */
+struct adsp_hw_timer_struct {
+ u32 match; /* Match value */
+ u32 count;
+ u32 enable; /* [1] - CLR_ON_MATCH_EN, [0] - EN */
+ u32 clear; /* one-shot register that clears the count */
+};
+
+/* Look for "TCX0" for related constants. */
+static __iomem struct adsp_hw_timer_struct *rtos_timer;
+
+static cycle_t timer_get_cycles(struct clocksource *cs)
+{
+ return (cycle_t) __vmgettime();
+}
+
+static struct clocksource hexagon_clocksource = {
+ .name = "pcycles",
+ .rating = 250,
+ .read = timer_get_cycles,
+ .mask = CLOCKSOURCE_MASK(64),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static int set_next_event(unsigned long delta, struct clock_event_device *evt)
+{
+ /* Assuming the timer will be disabled when we enter here. */
+
+ iowrite32(1, &rtos_timer->clear);
+ iowrite32(0, &rtos_timer->clear);
+
+ iowrite32(delta, &rtos_timer->match);
+ iowrite32(1 << TIMER_ENABLE, &rtos_timer->enable);
+ return 0;
+}
+
+/*
+ * Sets the mode (periodic, shutdown, oneshot, etc) of a timer.
+ */
+static void set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ switch (mode) {
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ /* XXX implement me */
+ default:
+ break;
+ }
+}
+
+#ifdef CONFIG_SMP
+/* Broadcast mechanism */
+static void broadcast(const struct cpumask *mask)
+{
+ send_ipi(mask, IPI_TIMER);
+}
+#endif
+
+static struct clock_event_device hexagon_clockevent_dev = {
+ .name = "clockevent",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .rating = 400,
+ .irq = RTOS_TIMER_INT,
+ .set_next_event = set_next_event,
+ .set_mode = set_mode,
+#ifdef CONFIG_SMP
+ .broadcast = broadcast,
+#endif
+};
+
+#ifdef CONFIG_SMP
+static DEFINE_PER_CPU(struct clock_event_device, clock_events);
+
+void setup_percpu_clockdev(void)
+{
+ int cpu = smp_processor_id();
+ struct clock_event_device *ce_dev = &hexagon_clockevent_dev;
+ struct clock_event_device *dummy_clock_dev =
+ &per_cpu(clock_events, cpu);
+
+ memcpy(dummy_clock_dev, ce_dev, sizeof(*dummy_clock_dev));
+ INIT_LIST_HEAD(&dummy_clock_dev->list);
+
+ dummy_clock_dev->features = CLOCK_EVT_FEAT_DUMMY;
+ dummy_clock_dev->cpumask = cpumask_of(cpu);
+ dummy_clock_dev->mode = CLOCK_EVT_MODE_UNUSED;
+
+ clockevents_register_device(dummy_clock_dev);
+}
+
+/* Called from smp.c for each CPU's timer ipi call */
+void ipi_timer(void)
+{
+ int cpu = smp_processor_id();
+ struct clock_event_device *ce_dev = &per_cpu(clock_events, cpu);
+
+ ce_dev->event_handler(ce_dev);
+}
+#endif /* CONFIG_SMP */
+
+static irqreturn_t timer_interrupt(int irq, void *devid)
+{
+ struct clock_event_device *ce_dev = &hexagon_clockevent_dev;
+
+ iowrite32(0, &rtos_timer->enable);
+ ce_dev->event_handler(ce_dev);
+
+ return IRQ_HANDLED;
+}
+
+/* This should also be pulled from devtree */
+static struct irqaction rtos_timer_intdesc = {
+ .handler = timer_interrupt,
+ .flags = IRQF_TIMER | IRQF_TRIGGER_RISING,
+ .name = "rtos_timer"
+};
+
+/*
+ * time_init_deferred - called by start_kernel to set up timer/clock source
+ *
+ * Install the IRQ handler for the clock, setup timers.
+ * This is done late, as that way, we can use ioremap().
+ *
+ * This runs just before the delay loop is calibrated, and
+ * is used for delay calibration.
+ */
+void __init time_init_deferred(void)
+{
+ struct resource *resource = NULL;
+ struct clock_event_device *ce_dev = &hexagon_clockevent_dev;
+ struct device_node *dn;
+ struct resource r;
+ int err;
+
+ ce_dev->cpumask = cpu_all_mask;
+
+ if (!resource)
+ resource = rtos_timer_device.resource;
+
+ /* ioremap here means this has to run later, after paging init */
+ rtos_timer = ioremap(resource->start, resource->end
+ - resource->start + 1);
+
+ if (!rtos_timer) {
+ release_mem_region(resource->start, resource->end
+ - resource->start + 1);
+ }
+ clocksource_register_khz(&hexagon_clocksource, pcycle_freq_mhz * 1000);
+
+ /* Note: the sim generic RTOS clock is apparently really 18750Hz */
+
+ /*
+ * Last arg is some guaranteed seconds for which the conversion will
+ * work without overflow.
+ */
+ clockevents_calc_mult_shift(ce_dev, sleep_clk_freq, 4);
+
+ ce_dev->max_delta_ns = clockevent_delta2ns(0x7fffffff, ce_dev);
+ ce_dev->min_delta_ns = clockevent_delta2ns(0xf, ce_dev);
+
+#ifdef CONFIG_SMP
+ setup_percpu_clockdev();
+#endif
+
+ clockevents_register_device(ce_dev);
+ setup_irq(ce_dev->irq, &rtos_timer_intdesc);
+}
+
+void __init time_init(void)
+{
+ late_time_init = time_init_deferred;
+}
+
+/*
+ * This could become parametric or perhaps even computed at run-time,
+ * but for now we take the observed simulator jitter.
+ */
+static long long fudgefactor = 350; /* Maybe lower if kernel optimized. */
+
+void __udelay(unsigned long usecs)
+{
+ unsigned long long start = __vmgettime();
+ unsigned long long finish = (pcycle_freq_mhz * usecs) - fudgefactor;
+
+ while ((__vmgettime() - start) < finish)
+ cpu_relax(); /* not sure how this improves readability */
+}
+EXPORT_SYMBOL(__udelay);