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
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
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
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
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
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
122 static u64 notrace hub_rt_read_sched_clock(void)
123 {
124 return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
125 }
126
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
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
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
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