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62b01943 PD |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Copyright (C) 2012 Regents of the University of California | |
4 | * Copyright (C) 2017 SiFive | |
2f12dbf1 | 5 | * |
4f9bbcef CH |
6 | * All RISC-V systems have a timer attached to every hart. These timers can |
7 | * either be read from the "time" and "timeh" CSRs, and can use the SBI to | |
8 | * setup events, or directly accessed using MMIO registers. | |
62b01943 | 9 | */ |
9f7a8ff6 AP |
10 | |
11 | #define pr_fmt(fmt) "riscv-timer: " fmt | |
12 | ||
62b01943 PD |
13 | #include <linux/clocksource.h> |
14 | #include <linux/clockchips.h> | |
15 | #include <linux/cpu.h> | |
16 | #include <linux/delay.h> | |
17 | #include <linux/irq.h> | |
033a65de | 18 | #include <linux/irqdomain.h> |
3a9f66cb | 19 | #include <linux/module.h> |
92e0d143 | 20 | #include <linux/sched_clock.h> |
4f9bbcef | 21 | #include <linux/io-64-nonatomic-lo-hi.h> |
033a65de AP |
22 | #include <linux/interrupt.h> |
23 | #include <linux/of_irq.h> | |
3a9f66cb | 24 | #include <clocksource/timer-riscv.h> |
f99fb607 | 25 | #include <asm/smp.h> |
9f7a8ff6 | 26 | #include <asm/hwcap.h> |
62b01943 | 27 | #include <asm/sbi.h> |
2bc3fc87 | 28 | #include <asm/timex.h> |
4f9bbcef | 29 | |
9f7a8ff6 | 30 | static DEFINE_STATIC_KEY_FALSE(riscv_sstc_available); |
8932a953 | 31 | static bool riscv_timer_cannot_wake_cpu; |
9f7a8ff6 | 32 | |
62b01943 PD |
33 | static int riscv_clock_next_event(unsigned long delta, |
34 | struct clock_event_device *ce) | |
35 | { | |
9f7a8ff6 AP |
36 | u64 next_tval = get_cycles64() + delta; |
37 | ||
a4c3733d | 38 | csr_set(CSR_IE, IE_TIE); |
9f7a8ff6 AP |
39 | if (static_branch_likely(&riscv_sstc_available)) { |
40 | #if defined(CONFIG_32BIT) | |
41 | csr_write(CSR_STIMECMP, next_tval & 0xFFFFFFFF); | |
42 | csr_write(CSR_STIMECMPH, next_tval >> 32); | |
43 | #else | |
44 | csr_write(CSR_STIMECMP, next_tval); | |
45 | #endif | |
46 | } else | |
47 | sbi_set_timer(next_tval); | |
48 | ||
62b01943 PD |
49 | return 0; |
50 | } | |
51 | ||
033a65de | 52 | static unsigned int riscv_clock_event_irq; |
62b01943 PD |
53 | static DEFINE_PER_CPU(struct clock_event_device, riscv_clock_event) = { |
54 | .name = "riscv_timer_clockevent", | |
d9f15a9d | 55 | .features = CLOCK_EVT_FEAT_ONESHOT, |
62b01943 PD |
56 | .rating = 100, |
57 | .set_next_event = riscv_clock_next_event, | |
58 | }; | |
59 | ||
60 | /* | |
61 | * It is guaranteed that all the timers across all the harts are synchronized | |
62 | * within one tick of each other, so while this could technically go | |
63 | * backwards when hopping between CPUs, practically it won't happen. | |
64 | */ | |
65 | static unsigned long long riscv_clocksource_rdtime(struct clocksource *cs) | |
66 | { | |
67 | return get_cycles64(); | |
68 | } | |
69 | ||
9d05c18e | 70 | static u64 notrace riscv_sched_clock(void) |
92e0d143 AP |
71 | { |
72 | return get_cycles64(); | |
73 | } | |
74 | ||
713203e3 | 75 | static struct clocksource riscv_clocksource = { |
62b01943 | 76 | .name = "riscv_clocksource", |
674402b0 | 77 | .rating = 400, |
32d0be01 | 78 | .mask = CLOCKSOURCE_MASK(64), |
62b01943 PD |
79 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
80 | .read = riscv_clocksource_rdtime, | |
3aff0403 LP |
81 | #if IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY) |
82 | .vdso_clock_mode = VDSO_CLOCKMODE_ARCHTIMER, | |
83 | #else | |
84 | .vdso_clock_mode = VDSO_CLOCKMODE_NONE, | |
85 | #endif | |
62b01943 PD |
86 | }; |
87 | ||
88 | static int riscv_timer_starting_cpu(unsigned int cpu) | |
89 | { | |
90 | struct clock_event_device *ce = per_cpu_ptr(&riscv_clock_event, cpu); | |
91 | ||
92 | ce->cpumask = cpumask_of(cpu); | |
033a65de | 93 | ce->irq = riscv_clock_event_irq; |
8932a953 AP |
94 | if (riscv_timer_cannot_wake_cpu) |
95 | ce->features |= CLOCK_EVT_FEAT_C3STOP; | |
62b01943 PD |
96 | clockevents_config_and_register(ce, riscv_timebase, 100, 0x7fffffff); |
97 | ||
033a65de AP |
98 | enable_percpu_irq(riscv_clock_event_irq, |
99 | irq_get_trigger_type(riscv_clock_event_irq)); | |
62b01943 PD |
100 | return 0; |
101 | } | |
102 | ||
103 | static int riscv_timer_dying_cpu(unsigned int cpu) | |
104 | { | |
033a65de | 105 | disable_percpu_irq(riscv_clock_event_irq); |
62b01943 PD |
106 | return 0; |
107 | } | |
108 | ||
3a9f66cb AP |
109 | void riscv_cs_get_mult_shift(u32 *mult, u32 *shift) |
110 | { | |
111 | *mult = riscv_clocksource.mult; | |
112 | *shift = riscv_clocksource.shift; | |
113 | } | |
114 | EXPORT_SYMBOL_GPL(riscv_cs_get_mult_shift); | |
115 | ||
62b01943 | 116 | /* called directly from the low-level interrupt handler */ |
033a65de | 117 | static irqreturn_t riscv_timer_interrupt(int irq, void *dev_id) |
62b01943 PD |
118 | { |
119 | struct clock_event_device *evdev = this_cpu_ptr(&riscv_clock_event); | |
120 | ||
a4c3733d | 121 | csr_clear(CSR_IE, IE_TIE); |
62b01943 | 122 | evdev->event_handler(evdev); |
033a65de AP |
123 | |
124 | return IRQ_HANDLED; | |
62b01943 PD |
125 | } |
126 | ||
127 | static int __init riscv_timer_init_dt(struct device_node *n) | |
128 | { | |
ad635e72 S |
129 | int cpuid, error; |
130 | unsigned long hartid; | |
033a65de AP |
131 | struct device_node *child; |
132 | struct irq_domain *domain; | |
62b01943 | 133 | |
ad635e72 S |
134 | error = riscv_of_processor_hartid(n, &hartid); |
135 | if (error < 0) { | |
136 | pr_warn("Not valid hartid for node [%pOF] error = [%lu]\n", | |
26478b2f | 137 | n, hartid); |
ad635e72 | 138 | return error; |
26478b2f AP |
139 | } |
140 | ||
f99fb607 | 141 | cpuid = riscv_hartid_to_cpuid(hartid); |
26478b2f | 142 | if (cpuid < 0) { |
ad635e72 | 143 | pr_warn("Invalid cpuid for hartid [%lu]\n", hartid); |
26478b2f AP |
144 | return cpuid; |
145 | } | |
f99fb607 AP |
146 | |
147 | if (cpuid != smp_processor_id()) | |
62b01943 PD |
148 | return 0; |
149 | ||
8932a953 AP |
150 | child = of_find_compatible_node(NULL, NULL, "riscv,timer"); |
151 | if (child) { | |
152 | riscv_timer_cannot_wake_cpu = of_property_read_bool(child, | |
153 | "riscv,timer-cannot-wake-cpu"); | |
154 | of_node_put(child); | |
155 | } | |
156 | ||
033a65de AP |
157 | domain = NULL; |
158 | child = of_get_compatible_child(n, "riscv,cpu-intc"); | |
159 | if (!child) { | |
160 | pr_err("Failed to find INTC node [%pOF]\n", n); | |
161 | return -ENODEV; | |
162 | } | |
163 | domain = irq_find_host(child); | |
164 | of_node_put(child); | |
165 | if (!domain) { | |
166 | pr_err("Failed to find IRQ domain for node [%pOF]\n", n); | |
167 | return -ENODEV; | |
168 | } | |
169 | ||
170 | riscv_clock_event_irq = irq_create_mapping(domain, RV_IRQ_TIMER); | |
171 | if (!riscv_clock_event_irq) { | |
172 | pr_err("Failed to map timer interrupt for node [%pOF]\n", n); | |
173 | return -ENODEV; | |
174 | } | |
175 | ||
ad635e72 | 176 | pr_info("%s: Registering clocksource cpuid [%d] hartid [%lu]\n", |
26478b2f | 177 | __func__, cpuid, hartid); |
713203e3 | 178 | error = clocksource_register_hz(&riscv_clocksource, riscv_timebase); |
26478b2f AP |
179 | if (error) { |
180 | pr_err("RISCV timer register failed [%d] for cpu = [%d]\n", | |
181 | error, cpuid); | |
182 | return error; | |
183 | } | |
62b01943 | 184 | |
32d0be01 | 185 | sched_clock_register(riscv_sched_clock, 64, riscv_timebase); |
92e0d143 | 186 | |
033a65de AP |
187 | error = request_percpu_irq(riscv_clock_event_irq, |
188 | riscv_timer_interrupt, | |
189 | "riscv-timer", &riscv_clock_event); | |
190 | if (error) { | |
191 | pr_err("registering percpu irq failed [%d]\n", error); | |
192 | return error; | |
193 | } | |
194 | ||
225b9596 ME |
195 | if (riscv_isa_extension_available(NULL, SSTC)) { |
196 | pr_info("Timer interrupt in S-mode is available via sstc extension\n"); | |
197 | static_branch_enable(&riscv_sstc_available); | |
198 | } | |
199 | ||
62b01943 PD |
200 | error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING, |
201 | "clockevents/riscv/timer:starting", | |
202 | riscv_timer_starting_cpu, riscv_timer_dying_cpu); | |
203 | if (error) | |
26478b2f AP |
204 | pr_err("cpu hp setup state failed for RISCV timer [%d]\n", |
205 | error); | |
9f7a8ff6 | 206 | |
62b01943 PD |
207 | return error; |
208 | } | |
209 | ||
210 | TIMER_OF_DECLARE(riscv_timer, "riscv", riscv_timer_init_dt); |