1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1999, 2000, 05, 06 Ralf Baechle (ralf@linux-mips.org)
4 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
5 */
6#include <linux/bcd.h>
7#include <linux/clockchips.h>
8#include <linux/init.h>
9#include <linux/kernel.h>
10#include <linux/sched.h>
11#include <linux/sched_clock.h>
12#include <linux/interrupt.h>
13#include <linux/kernel_stat.h>
14#include <linux/param.h>
15#include <linux/smp.h>
16#include <linux/time.h>
17#include <linux/timex.h>
18#include <linux/mm.h>
19#include <linux/platform_device.h>
20
21#include <asm/time.h>
22#include <asm/sgialib.h>
23#include <asm/sn/klconfig.h>
24#include <asm/sn/arch.h>
25#include <asm/sn/addrs.h>
26#include <asm/sn/agent.h>
27
28#include "ip27-common.h"
29
30static int rt_next_event(unsigned long delta, struct clock_event_device *evt)
31{
32	unsigned int cpu = smp_processor_id();
33	int slice = cputoslice(cpu);
34	unsigned long cnt;
35
36	cnt = LOCAL_HUB_L(PI_RT_COUNT);
37	cnt += delta;
38	LOCAL_HUB_S(PI_RT_COMPARE_A + PI_COUNT_OFFSET * slice, cnt);
39
40	return LOCAL_HUB_L(PI_RT_COUNT) >= cnt ? -ETIME : 0;
41}
42
43static DEFINE_PER_CPU(struct clock_event_device, hub_rt_clockevent);
44static DEFINE_PER_CPU(char [11], hub_rt_name);
45
46static irqreturn_t hub_rt_counter_handler(int irq, void *dev_id)
47{
48	unsigned int cpu = smp_processor_id();
49	struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
50	int slice = cputoslice(cpu);
51
52	/*
53	 * Ack
54	 */
55	LOCAL_HUB_S(PI_RT_PEND_A + PI_COUNT_OFFSET * slice, 0);
56	cd->event_handler(cd);
57
58	return IRQ_HANDLED;
59}
60
61struct irqaction hub_rt_irqaction = {
62	.handler	= hub_rt_counter_handler,
63	.percpu_dev_id	= &hub_rt_clockevent,
64	.flags		= IRQF_PERCPU | IRQF_TIMER,
65	.name		= "hub-rt",
66};
67
68/*
69 * This is a hack; we really need to figure these values out dynamically
70 *
71 * Since 800 ns works very well with various HUB frequencies, such as
72 * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
73 *
74 * Ralf: which clock rate is used to feed the counter?
75 */
76#define NSEC_PER_CYCLE		800
77#define CYCLES_PER_SEC		(NSEC_PER_SEC / NSEC_PER_CYCLE)
78
79void hub_rt_clock_event_init(void)
80{
81	unsigned int cpu = smp_processor_id();
82	struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
83	unsigned char *name = per_cpu(hub_rt_name, cpu);
84
85	sprintf(name, "hub-rt %d", cpu);
86	cd->name		= name;
87	cd->features		= CLOCK_EVT_FEAT_ONESHOT;
88	clockevent_set_clock(cd, CYCLES_PER_SEC);
89	cd->max_delta_ns	= clockevent_delta2ns(0xfffffffffffff, cd);
90	cd->max_delta_ticks	= 0xfffffffffffff;
91	cd->min_delta_ns	= clockevent_delta2ns(0x300, cd);
92	cd->min_delta_ticks	= 0x300;
93	cd->rating		= 200;
94	cd->irq			= IP27_RT_TIMER_IRQ;
95	cd->cpumask		= cpumask_of(cpu);
96	cd->set_next_event	= rt_next_event;
97	clockevents_register_device(cd);
98
99	enable_percpu_irq(IP27_RT_TIMER_IRQ, IRQ_TYPE_NONE);
100}
101
102static void __init hub_rt_clock_event_global_init(void)
103{
104	irq_set_handler(IP27_RT_TIMER_IRQ, handle_percpu_devid_irq);
105	irq_set_percpu_devid(IP27_RT_TIMER_IRQ);
106	setup_percpu_irq(IP27_RT_TIMER_IRQ, &hub_rt_irqaction);
107}
108
109static u64 hub_rt_read(struct clocksource *cs)
110{
111	return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
112}
113
114struct clocksource hub_rt_clocksource = {
115	.name	= "HUB-RT",
116	.rating = 200,
117	.read	= hub_rt_read,
118	.mask	= CLOCKSOURCE_MASK(52),
119	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
120};
121
122static u64 notrace hub_rt_read_sched_clock(void)
123{
124	return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
125}
126
127static void __init hub_rt_clocksource_init(void)
128{
129	struct clocksource *cs = &hub_rt_clocksource;
130
131	clocksource_register_hz(cs, CYCLES_PER_SEC);
132
133	sched_clock_register(hub_rt_read_sched_clock, 52, CYCLES_PER_SEC);
134}
135
136void __init plat_time_init(void)
137{
138	hub_rt_clocksource_init();
139	hub_rt_clock_event_global_init();
140	hub_rt_clock_event_init();
141}
142
143void hub_rtc_init(nasid_t nasid)
144{
145
146	/*
147	 * We only need to initialize the current node.
148	 * If this is not the current node then it is a cpuless
149	 * node and timeouts will not happen there.
150	 */
151	if (get_nasid() == nasid) {
152		LOCAL_HUB_S(PI_RT_EN_A, 1);
153		LOCAL_HUB_S(PI_RT_EN_B, 1);
154		LOCAL_HUB_S(PI_PROF_EN_A, 0);
155		LOCAL_HUB_S(PI_PROF_EN_B, 0);
156		LOCAL_HUB_S(PI_RT_COUNT, 0);
157		LOCAL_HUB_S(PI_RT_PEND_A, 0);
158		LOCAL_HUB_S(PI_RT_PEND_B, 0);
159	}
160}
161