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
40 static unsigned long atlas7_timer_rate;
41
42 static 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
51 static u32 sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT];
52
53 static void __iomem *sirfsoc_timer_base;
54
55 /* disable count and interrupt */
sirfsoc_timer_count_disable(int idx)56 static 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 */
sirfsoc_timer_count_enable(int idx)63 static 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 */
sirfsoc_timer_interrupt(int irq,void * dev_id)70 static 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 */
sirfsoc_timer_read(struct clocksource * cs)87 static 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
sirfsoc_timer_set_next_event(unsigned long delta,struct clock_event_device * ce)100 static 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 */
sirfsoc_timer_shutdown(struct clock_event_device * evt)120 static int sirfsoc_timer_shutdown(struct clock_event_device *evt)
121 {
122 sirfsoc_timer_count_disable(smp_processor_id());
123 return 0;
124 }
125
sirfsoc_clocksource_suspend(struct clocksource * cs)126 static 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
sirfsoc_clocksource_resume(struct clocksource * cs)134 static 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
150 static struct clock_event_device __percpu *sirfsoc_clockevent;
151
152 static 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
162 static struct irqaction sirfsoc_timer_irq = {
163 .name = "sirfsoc_timer0",
164 .flags = IRQF_TIMER | IRQF_NOBALANCING,
165 .handler = sirfsoc_timer_interrupt,
166 };
167
168 static struct irqaction sirfsoc_timer1_irq = {
169 .name = "sirfsoc_timer1",
170 .flags = IRQF_TIMER | IRQF_NOBALANCING,
171 .handler = sirfsoc_timer_interrupt,
172 };
173
sirfsoc_local_timer_starting_cpu(unsigned int cpu)174 static 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
sirfsoc_local_timer_dying_cpu(unsigned int cpu)207 static 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
sirfsoc_clockevent_init(void)218 static 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 */
sirfsoc_atlas7_timer_init(struct device_node * np)231 static 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
sirfsoc_of_timer_init(struct device_node * np)263 static 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 }
285 TIMER_OF_DECLARE(sirfsoc_atlas7_timer, "sirf,atlas7-tick", sirfsoc_of_timer_init);
286