linux/drivers/clocksource/numachip.c

96 lines
2.6 KiB
C

/*
*
* Copyright (C) 2015 Numascale AS. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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.
*
*/
#include <linux/clockchips.h>
#include <asm/irq.h>
#include <asm/numachip/numachip.h>
#include <asm/numachip/numachip_csr.h>
static DEFINE_PER_CPU(struct clock_event_device, numachip2_ced);
static cycles_t numachip2_timer_read(struct clocksource *cs)
{
return numachip2_read64_lcsr(NUMACHIP2_TIMER_NOW);
}
static struct clocksource numachip2_clocksource = {
.name = "numachip2",
.rating = 295,
.read = numachip2_timer_read,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.mult = 1,
.shift = 0,
};
static int numachip2_set_next_event(unsigned long delta, struct clock_event_device *ced)
{
numachip2_write64_lcsr(NUMACHIP2_TIMER_DEADLINE + numachip2_timer(),
delta);
return 0;
}
static struct clock_event_device numachip2_clockevent = {
.name = "numachip2",
.rating = 400,
.set_next_event = numachip2_set_next_event,
.features = CLOCK_EVT_FEAT_ONESHOT,
.mult = 1,
.shift = 0,
.min_delta_ns = 1250,
.max_delta_ns = LONG_MAX,
};
static void numachip_timer_interrupt(void)
{
struct clock_event_device *ced = this_cpu_ptr(&numachip2_ced);
ced->event_handler(ced);
}
static __init void numachip_timer_each(struct work_struct *work)
{
unsigned local_apicid = __this_cpu_read(x86_cpu_to_apicid) & 0xff;
struct clock_event_device *ced = this_cpu_ptr(&numachip2_ced);
/* Setup IPI vector to local core and relative timing mode */
numachip2_write64_lcsr(NUMACHIP2_TIMER_INT + numachip2_timer(),
(3 << 22) | (X86_PLATFORM_IPI_VECTOR << 14) |
(local_apicid << 6));
*ced = numachip2_clockevent;
ced->cpumask = cpumask_of(smp_processor_id());
clockevents_register_device(ced);
}
static int __init numachip_timer_init(void)
{
if (numachip_system != 2)
return -ENODEV;
/* Reset timer */
numachip2_write64_lcsr(NUMACHIP2_TIMER_RESET, 0);
clocksource_register_hz(&numachip2_clocksource, NSEC_PER_SEC);
/* Setup per-cpu clockevents */
x86_platform_ipi_callback = numachip_timer_interrupt;
schedule_on_each_cpu(&numachip_timer_each);
return 0;
}
arch_initcall(numachip_timer_init);