1/*
2 *
3 * Copyright (C) 2015 Numascale AS. All rights reserved.
4 *
5 * This software is licensed under the terms of the GNU General Public
6 * License version 2, as published by the Free Software Foundation, and
7 * may be copied, distributed, and modified under those terms.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 */
15
16#include <linux/clockchips.h>
17
18#include <asm/irq.h>
19#include <asm/numachip/numachip.h>
20#include <asm/numachip/numachip_csr.h>
21
22static DEFINE_PER_CPU(struct clock_event_device, numachip2_ced);
23
24static cycles_t numachip2_timer_read(struct clocksource *cs)
25{
26	return numachip2_read64_lcsr(NUMACHIP2_TIMER_NOW);
27}
28
29static struct clocksource numachip2_clocksource = {
30	.name            = "numachip2",
31	.rating          = 295,
32	.read            = numachip2_timer_read,
33	.mask            = CLOCKSOURCE_MASK(64),
34	.flags           = CLOCK_SOURCE_IS_CONTINUOUS,
35	.mult            = 1,
36	.shift           = 0,
37};
38
39static int numachip2_set_next_event(unsigned long delta, struct clock_event_device *ced)
40{
41	numachip2_write64_lcsr(NUMACHIP2_TIMER_DEADLINE + numachip2_timer(),
42		delta);
43	return 0;
44}
45
46static struct clock_event_device numachip2_clockevent = {
47	.name            = "numachip2",
48	.rating          = 400,
49	.set_next_event  = numachip2_set_next_event,
50	.features        = CLOCK_EVT_FEAT_ONESHOT,
51	.mult            = 1,
52	.shift           = 0,
53	.min_delta_ns    = 1250,
54	.max_delta_ns    = LONG_MAX,
55};
56
57static void numachip_timer_interrupt(void)
58{
59	struct clock_event_device *ced = this_cpu_ptr(&numachip2_ced);
60
61	ced->event_handler(ced);
62}
63
64static __init void numachip_timer_each(struct work_struct *work)
65{
66	unsigned local_apicid = __this_cpu_read(x86_cpu_to_apicid) & 0xff;
67	struct clock_event_device *ced = this_cpu_ptr(&numachip2_ced);
68
69	/* Setup IPI vector to local core and relative timing mode */
70	numachip2_write64_lcsr(NUMACHIP2_TIMER_INT + numachip2_timer(),
71		(3 << 22) | (X86_PLATFORM_IPI_VECTOR << 14) |
72		(local_apicid << 6));
73
74	*ced = numachip2_clockevent;
75	ced->cpumask = cpumask_of(smp_processor_id());
76	clockevents_register_device(ced);
77}
78
79static int __init numachip_timer_init(void)
80{
81	if (numachip_system != 2)
82		return -ENODEV;
83
84	/* Reset timer */
85	numachip2_write64_lcsr(NUMACHIP2_TIMER_RESET, 0);
86	clocksource_register_hz(&numachip2_clocksource, NSEC_PER_SEC);
87
88	/* Setup per-cpu clockevents */
89	x86_platform_ipi_callback = numachip_timer_interrupt;
90	schedule_on_each_cpu(&numachip_timer_each);
91
92	return 0;
93}
94
95arch_initcall(numachip_timer_init);
96