tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * System timer for CSR SiRFprimaII
4 *
5 * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
6 */
7
8#include <linux/kernel.h>
9#include <linux/interrupt.h>
10#include <linux/clockchips.h>
11#include <linux/clocksource.h>
12#include <linux/cpu.h>
13#include <linux/bitops.h>
14#include <linux/irq.h>
15#include <linux/clk.h>
16#include <linux/slab.h>
17#include <linux/of.h>
18#include <linux/of_irq.h>
19#include <linux/of_address.h>
20#include <linux/sched_clock.h>
21
22#define SIRFSOC_TIMER_32COUNTER_0_CTRL 0x0000
23#define SIRFSOC_TIMER_32COUNTER_1_CTRL 0x0004
24#define SIRFSOC_TIMER_MATCH_0 0x0018
25#define SIRFSOC_TIMER_MATCH_1 0x001c
26#define SIRFSOC_TIMER_COUNTER_0 0x0048
27#define SIRFSOC_TIMER_COUNTER_1 0x004c
28#define SIRFSOC_TIMER_INTR_STATUS 0x0060
29#define SIRFSOC_TIMER_WATCHDOG_EN 0x0064
30#define SIRFSOC_TIMER_64COUNTER_CTRL 0x0068
31#define SIRFSOC_TIMER_64COUNTER_LO 0x006c
32#define SIRFSOC_TIMER_64COUNTER_HI 0x0070
33#define SIRFSOC_TIMER_64COUNTER_LOAD_LO 0x0074
34#define SIRFSOC_TIMER_64COUNTER_LOAD_HI 0x0078
35#define SIRFSOC_TIMER_64COUNTER_RLATCHED_LO 0x007c
36#define SIRFSOC_TIMER_64COUNTER_RLATCHED_HI 0x0080
37
38#define SIRFSOC_TIMER_REG_CNT 6
39
40static unsigned long atlas7_timer_rate;
41
42static const u32 sirfsoc_timer_reg_list[SIRFSOC_TIMER_REG_CNT] = {
43 SIRFSOC_TIMER_WATCHDOG_EN,
44 SIRFSOC_TIMER_32COUNTER_0_CTRL,
45 SIRFSOC_TIMER_32COUNTER_1_CTRL,
46 SIRFSOC_TIMER_64COUNTER_CTRL,
47 SIRFSOC_TIMER_64COUNTER_RLATCHED_LO,
48 SIRFSOC_TIMER_64COUNTER_RLATCHED_HI,
49};
50
51static u32 sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT];
52
53static void __iomem *sirfsoc_timer_base;
54
55/* disable count and interrupt */
56static inline void sirfsoc_timer_count_disable(int idx)
57{
58 writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) & ~0x7,
59 sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx);
60}
61
62/* enable count and interrupt */
63static inline void sirfsoc_timer_count_enable(int idx)
64{
65 writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) | 0x3,
66 sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx);
67}
68
69/* timer interrupt handler */
70static irqreturn_t sirfsoc_timer_interrupt(int irq, void *dev_id)
71{
72 struct clock_event_device *ce = dev_id;
73 int cpu = smp_processor_id();
74
75 /* clear timer interrupt */
76 writel_relaxed(BIT(cpu), sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);
77
78 if (clockevent_state_oneshot(ce))
79 sirfsoc_timer_count_disable(cpu);
80
81 ce->event_handler(ce);
82
83 return IRQ_HANDLED;
84}
85
86/* read 64-bit timer counter */
87static u64 sirfsoc_timer_read(struct clocksource *cs)
88{
89 u64 cycles;
90
91 writel_relaxed((readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
92 BIT(0)) & ~BIT(1), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
93
94 cycles = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_HI);
95 cycles = (cycles << 32) | readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_LO);
96
97 return cycles;
98}
99
100static int sirfsoc_timer_set_next_event(unsigned long delta,
101 struct clock_event_device *ce)
102{
103 int cpu = smp_processor_id();
104
105 /* disable timer first, then modify the related registers */
106 sirfsoc_timer_count_disable(cpu);
107
108 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0 +
109 4 * cpu);
110 writel_relaxed(delta, sirfsoc_timer_base + SIRFSOC_TIMER_MATCH_0 +
111 4 * cpu);
112
113 /* enable the tick */
114 sirfsoc_timer_count_enable(cpu);
115
116 return 0;
117}
118
119/* Oneshot is enabled in set_next_event */
120static int sirfsoc_timer_shutdown(struct clock_event_device *evt)
121{
122 sirfsoc_timer_count_disable(smp_processor_id());
123 return 0;
124}
125
126static void sirfsoc_clocksource_suspend(struct clocksource *cs)
127{
128 int i;
129
130 for (i = 0; i < SIRFSOC_TIMER_REG_CNT; i++)
131 sirfsoc_timer_reg_val[i] = readl_relaxed(sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
132}
133
134static void sirfsoc_clocksource_resume(struct clocksource *cs)
135{
136 int i;
137
138 for (i = 0; i < SIRFSOC_TIMER_REG_CNT - 2; i++)
139 writel_relaxed(sirfsoc_timer_reg_val[i], sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
140
141 writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 2],
142 sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
143 writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 1],
144 sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
145
146 writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
147 BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
148}
149
150static struct clock_event_device __percpu *sirfsoc_clockevent;
151
152static struct clocksource sirfsoc_clocksource = {
153 .name = "sirfsoc_clocksource",
154 .rating = 200,
155 .mask = CLOCKSOURCE_MASK(64),
156 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
157 .read = sirfsoc_timer_read,
158 .suspend = sirfsoc_clocksource_suspend,
159 .resume = sirfsoc_clocksource_resume,
160};
161
162static struct irqaction sirfsoc_timer_irq = {
163 .name = "sirfsoc_timer0",
164 .flags = IRQF_TIMER | IRQF_NOBALANCING,
165 .handler = sirfsoc_timer_interrupt,
166};
167
168static struct irqaction sirfsoc_timer1_irq = {
169 .name = "sirfsoc_timer1",
170 .flags = IRQF_TIMER | IRQF_NOBALANCING,
171 .handler = sirfsoc_timer_interrupt,
172};
173
174static int sirfsoc_local_timer_starting_cpu(unsigned int cpu)
175{
176 struct clock_event_device *ce = per_cpu_ptr(sirfsoc_clockevent, cpu);
177 struct irqaction *action;
178
179 if (cpu == 0)
180 action = &sirfsoc_timer_irq;
181 else
182 action = &sirfsoc_timer1_irq;
183
184 ce->irq = action->irq;
185 ce->name = "local_timer";
186 ce->features = CLOCK_EVT_FEAT_ONESHOT;
187 ce->rating = 200;
188 ce->set_state_shutdown = sirfsoc_timer_shutdown;
189 ce->set_state_oneshot = sirfsoc_timer_shutdown;
190 ce->tick_resume = sirfsoc_timer_shutdown;
191 ce->set_next_event = sirfsoc_timer_set_next_event;
192 clockevents_calc_mult_shift(ce, atlas7_timer_rate, 60);
193 ce->max_delta_ns = clockevent_delta2ns(-2, ce);
194 ce->max_delta_ticks = (unsigned long)-2;
195 ce->min_delta_ns = clockevent_delta2ns(2, ce);
196 ce->min_delta_ticks = 2;
197 ce->cpumask = cpumask_of(cpu);
198
199 action->dev_id = ce;
200 BUG_ON(setup_irq(ce->irq, action));
201 irq_force_affinity(action->irq, cpumask_of(cpu));
202
203 clockevents_register_device(ce);
204 return 0;
205}
206
207static int sirfsoc_local_timer_dying_cpu(unsigned int cpu)
208{
209 sirfsoc_timer_count_disable(1);
210
211 if (cpu == 0)
212 remove_irq(sirfsoc_timer_irq.irq, &sirfsoc_timer_irq);
213 else
214 remove_irq(sirfsoc_timer1_irq.irq, &sirfsoc_timer1_irq);
215 return 0;
216}
217
218static int __init sirfsoc_clockevent_init(void)
219{
220 sirfsoc_clockevent = alloc_percpu(struct clock_event_device);
221 BUG_ON(!sirfsoc_clockevent);
222
223 /* Install and invoke hotplug callbacks */
224 return cpuhp_setup_state(CPUHP_AP_MARCO_TIMER_STARTING,
225 "clockevents/marco:starting",
226 sirfsoc_local_timer_starting_cpu,
227 sirfsoc_local_timer_dying_cpu);
228}
229
230/* initialize the kernel jiffy timer source */
231static int __init sirfsoc_atlas7_timer_init(struct device_node *np)
232{
233 struct clk *clk;
234
235 clk = of_clk_get(np, 0);
236 BUG_ON(IS_ERR(clk));
237
238 BUG_ON(clk_prepare_enable(clk));
239
240 atlas7_timer_rate = clk_get_rate(clk);
241
242 /* timer dividers: 0, not divided */
243 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
244 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL);
245 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_1_CTRL);
246
247 /* Initialize timer counters to 0 */
248 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
249 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
250 writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
251 BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
252 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0);
253 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_1);
254
255 /* Clear all interrupts */
256 writel_relaxed(0xFFFF, sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);
257
258 BUG_ON(clocksource_register_hz(&sirfsoc_clocksource, atlas7_timer_rate));
259
260 return sirfsoc_clockevent_init();
261}
262
263static int __init sirfsoc_of_timer_init(struct device_node *np)
264{
265 sirfsoc_timer_base = of_iomap(np, 0);
266 if (!sirfsoc_timer_base) {
267 pr_err("unable to map timer cpu registers\n");
268 return -ENXIO;
269 }
270
271 sirfsoc_timer_irq.irq = irq_of_parse_and_map(np, 0);
272 if (!sirfsoc_timer_irq.irq) {
273 pr_err("No irq passed for timer0 via DT\n");
274 return -EINVAL;
275 }
276
277 sirfsoc_timer1_irq.irq = irq_of_parse_and_map(np, 1);
278 if (!sirfsoc_timer1_irq.irq) {
279 pr_err("No irq passed for timer1 via DT\n");
280 return -EINVAL;
281 }
282
283 return sirfsoc_atlas7_timer_init(np);
284}
285TIMER_OF_DECLARE(sirfsoc_atlas7_timer, "sirf,atlas7-tick", sirfsoc_of_timer_init);