tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 const struct clock_event_device numachip2_clockevent __initconst = {
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 .min_delta_ticks = 1250,
55 .max_delta_ns = LONG_MAX,
56 .max_delta_ticks = LONG_MAX,
57};
58
59static void numachip_timer_interrupt(void)
60{
61 struct clock_event_device *ced = this_cpu_ptr(&numachip2_ced);
62
63 ced->event_handler(ced);
64}
65
66static __init void numachip_timer_each(struct work_struct *work)
67{
68 unsigned local_apicid = __this_cpu_read(x86_cpu_to_apicid) & 0xff;
69 struct clock_event_device *ced = this_cpu_ptr(&numachip2_ced);
70
71 /* Setup IPI vector to local core and relative timing mode */
72 numachip2_write64_lcsr(NUMACHIP2_TIMER_INT + numachip2_timer(),
73 (3 << 22) | (X86_PLATFORM_IPI_VECTOR << 14) |
74 (local_apicid << 6));
75
76 *ced = numachip2_clockevent;
77 ced->cpumask = cpumask_of(smp_processor_id());
78 clockevents_register_device(ced);
79}
80
81static int __init numachip_timer_init(void)
82{
83 if (numachip_system != 2)
84 return -ENODEV;
85
86 /* Reset timer */
87 numachip2_write64_lcsr(NUMACHIP2_TIMER_RESET, 0);
88 clocksource_register_hz(&numachip2_clocksource, NSEC_PER_SEC);
89
90 /* Setup per-cpu clockevents */
91 x86_platform_ipi_callback = numachip_timer_interrupt;
92 schedule_on_each_cpu(&numachip_timer_each);
93
94 return 0;
95}
96
97arch_initcall(numachip_timer_init);