xref: /linux/drivers/clocksource/numachip.c (revision 75bf465f0bc33e9b776a46d6a1b9b990f5fb7c37)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *
4  * Copyright (C) 2015 Numascale AS. All rights reserved.
5  */
6 
7 #include <linux/clockchips.h>
8 
9 #include <asm/irq.h>
10 #include <asm/numachip/numachip.h>
11 #include <asm/numachip/numachip_csr.h>
12 
13 static DEFINE_PER_CPU(struct clock_event_device, numachip2_ced);
14 
numachip2_timer_read(struct clocksource * cs)15 static cycles_t numachip2_timer_read(struct clocksource *cs)
16 {
17 	return numachip2_read64_lcsr(NUMACHIP2_TIMER_NOW);
18 }
19 
20 static struct clocksource numachip2_clocksource = {
21 	.name            = "numachip2",
22 	.rating          = 295,
23 	.read            = numachip2_timer_read,
24 	.mask            = CLOCKSOURCE_MASK(64),
25 	.flags           = CLOCK_SOURCE_IS_CONTINUOUS,
26 	.mult            = 1,
27 	.shift           = 0,
28 };
29 
numachip2_set_next_event(unsigned long delta,struct clock_event_device * ced)30 static int numachip2_set_next_event(unsigned long delta, struct clock_event_device *ced)
31 {
32 	numachip2_write64_lcsr(NUMACHIP2_TIMER_DEADLINE + numachip2_timer(),
33 		delta);
34 	return 0;
35 }
36 
37 static const struct clock_event_device numachip2_clockevent __initconst = {
38 	.name            = "numachip2",
39 	.rating          = 400,
40 	.set_next_event  = numachip2_set_next_event,
41 	.features        = CLOCK_EVT_FEAT_ONESHOT,
42 	.mult            = 1,
43 	.shift           = 0,
44 	.min_delta_ns    = 1250,
45 	.min_delta_ticks = 1250,
46 	.max_delta_ns    = LONG_MAX,
47 	.max_delta_ticks = LONG_MAX,
48 };
49 
numachip_timer_interrupt(void)50 static void numachip_timer_interrupt(void)
51 {
52 	struct clock_event_device *ced = this_cpu_ptr(&numachip2_ced);
53 
54 	ced->event_handler(ced);
55 }
56 
numachip_timer_each(struct work_struct * work)57 static __init void numachip_timer_each(struct work_struct *work)
58 {
59 	unsigned local_apicid = __this_cpu_read(x86_cpu_to_apicid) & 0xff;
60 	struct clock_event_device *ced = this_cpu_ptr(&numachip2_ced);
61 
62 	/* Setup IPI vector to local core and relative timing mode */
63 	numachip2_write64_lcsr(NUMACHIP2_TIMER_INT + numachip2_timer(),
64 		(3 << 22) | (X86_PLATFORM_IPI_VECTOR << 14) |
65 		(local_apicid << 6));
66 
67 	*ced = numachip2_clockevent;
68 	ced->cpumask = cpumask_of(smp_processor_id());
69 	clockevents_register_device(ced);
70 }
71 
numachip_timer_init(void)72 static int __init numachip_timer_init(void)
73 {
74 	if (numachip_system != 2)
75 		return -ENODEV;
76 
77 	/* Reset timer */
78 	numachip2_write64_lcsr(NUMACHIP2_TIMER_RESET, 0);
79 	clocksource_register_hz(&numachip2_clocksource, NSEC_PER_SEC);
80 
81 	/* Setup per-cpu clockevents */
82 	x86_platform_ipi_callback = numachip_timer_interrupt;
83 	schedule_on_each_cpu(&numachip_timer_each);
84 
85 	return 0;
86 }
87 
88 arch_initcall(numachip_timer_init);
89