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 
rt_next_event(unsigned long delta,struct clock_event_device * evt)30 static 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 
43 static DEFINE_PER_CPU(struct clock_event_device, hub_rt_clockevent);
44 static DEFINE_PER_CPU(char [11], hub_rt_name);
45 
hub_rt_counter_handler(int irq,void * dev_id)46 static 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 
61 struct 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 
hub_rt_clock_event_init(void)79 void 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 
hub_rt_clock_event_global_init(void)102 static 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 
hub_rt_read(struct clocksource * cs)109 static u64 hub_rt_read(struct clocksource *cs)
110 {
111 	return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
112 }
113 
114 struct 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 
hub_rt_read_sched_clock(void)122 static u64 notrace hub_rt_read_sched_clock(void)
123 {
124 	return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
125 }
126 
hub_rt_clocksource_init(void)127 static 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 
plat_time_init(void)136 void __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 
hub_rtc_init(nasid_t nasid)143 void 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