1 /*
2 * System timer for CSR SiRFprimaII
3 *
4 * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
5 *
6 * Licensed under GPLv2 or later.
7 */
8
9 #include <linux/kernel.h>
10 #include <linux/interrupt.h>
11 #include <linux/clockchips.h>
12 #include <linux/clocksource.h>
13 #include <linux/cpu.h>
14 #include <linux/bitops.h>
15 #include <linux/irq.h>
16 #include <linux/clk.h>
17 #include <linux/slab.h>
18 #include <linux/of.h>
19 #include <linux/of_irq.h>
20 #include <linux/of_address.h>
21 #include <linux/sched_clock.h>
22
23 #define SIRFSOC_TIMER_32COUNTER_0_CTRL 0x0000
24 #define SIRFSOC_TIMER_32COUNTER_1_CTRL 0x0004
25 #define SIRFSOC_TIMER_MATCH_0 0x0018
26 #define SIRFSOC_TIMER_MATCH_1 0x001c
27 #define SIRFSOC_TIMER_COUNTER_0 0x0048
28 #define SIRFSOC_TIMER_COUNTER_1 0x004c
29 #define SIRFSOC_TIMER_INTR_STATUS 0x0060
30 #define SIRFSOC_TIMER_WATCHDOG_EN 0x0064
31 #define SIRFSOC_TIMER_64COUNTER_CTRL 0x0068
32 #define SIRFSOC_TIMER_64COUNTER_LO 0x006c
33 #define SIRFSOC_TIMER_64COUNTER_HI 0x0070
34 #define SIRFSOC_TIMER_64COUNTER_LOAD_LO 0x0074
35 #define SIRFSOC_TIMER_64COUNTER_LOAD_HI 0x0078
36 #define SIRFSOC_TIMER_64COUNTER_RLATCHED_LO 0x007c
37 #define SIRFSOC_TIMER_64COUNTER_RLATCHED_HI 0x0080
38
39 #define SIRFSOC_TIMER_REG_CNT 6
40
41 static unsigned long atlas7_timer_rate;
42
43 static const u32 sirfsoc_timer_reg_list[SIRFSOC_TIMER_REG_CNT] = {
44 SIRFSOC_TIMER_WATCHDOG_EN,
45 SIRFSOC_TIMER_32COUNTER_0_CTRL,
46 SIRFSOC_TIMER_32COUNTER_1_CTRL,
47 SIRFSOC_TIMER_64COUNTER_CTRL,
48 SIRFSOC_TIMER_64COUNTER_RLATCHED_LO,
49 SIRFSOC_TIMER_64COUNTER_RLATCHED_HI,
50 };
51
52 static u32 sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT];
53
54 static void __iomem *sirfsoc_timer_base;
55
56 /* disable count and interrupt */
sirfsoc_timer_count_disable(int idx)57 static inline void sirfsoc_timer_count_disable(int idx)
58 {
59 writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) & ~0x7,
60 sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx);
61 }
62
63 /* enable count and interrupt */
sirfsoc_timer_count_enable(int idx)64 static inline void sirfsoc_timer_count_enable(int idx)
65 {
66 writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) | 0x3,
67 sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx);
68 }
69
70 /* timer interrupt handler */
sirfsoc_timer_interrupt(int irq,void * dev_id)71 static irqreturn_t sirfsoc_timer_interrupt(int irq, void *dev_id)
72 {
73 struct clock_event_device *ce = dev_id;
74 int cpu = smp_processor_id();
75
76 /* clear timer interrupt */
77 writel_relaxed(BIT(cpu), sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);
78
79 if (clockevent_state_oneshot(ce))
80 sirfsoc_timer_count_disable(cpu);
81
82 ce->event_handler(ce);
83
84 return IRQ_HANDLED;
85 }
86
87 /* read 64-bit timer counter */
sirfsoc_timer_read(struct clocksource * cs)88 static u64 sirfsoc_timer_read(struct clocksource *cs)
89 {
90 u64 cycles;
91
92 writel_relaxed((readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
93 BIT(0)) & ~BIT(1), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
94
95 cycles = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_HI);
96 cycles = (cycles << 32) | readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_LO);
97
98 return cycles;
99 }
100
sirfsoc_timer_set_next_event(unsigned long delta,struct clock_event_device * ce)101 static int sirfsoc_timer_set_next_event(unsigned long delta,
102 struct clock_event_device *ce)
103 {
104 int cpu = smp_processor_id();
105
106 /* disable timer first, then modify the related registers */
107 sirfsoc_timer_count_disable(cpu);
108
109 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0 +
110 4 * cpu);
111 writel_relaxed(delta, sirfsoc_timer_base + SIRFSOC_TIMER_MATCH_0 +
112 4 * cpu);
113
114 /* enable the tick */
115 sirfsoc_timer_count_enable(cpu);
116
117 return 0;
118 }
119
120 /* Oneshot is enabled in set_next_event */
sirfsoc_timer_shutdown(struct clock_event_device * evt)121 static int sirfsoc_timer_shutdown(struct clock_event_device *evt)
122 {
123 sirfsoc_timer_count_disable(smp_processor_id());
124 return 0;
125 }
126
sirfsoc_clocksource_suspend(struct clocksource * cs)127 static void sirfsoc_clocksource_suspend(struct clocksource *cs)
128 {
129 int i;
130
131 for (i = 0; i < SIRFSOC_TIMER_REG_CNT; i++)
132 sirfsoc_timer_reg_val[i] = readl_relaxed(sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
133 }
134
sirfsoc_clocksource_resume(struct clocksource * cs)135 static void sirfsoc_clocksource_resume(struct clocksource *cs)
136 {
137 int i;
138
139 for (i = 0; i < SIRFSOC_TIMER_REG_CNT - 2; i++)
140 writel_relaxed(sirfsoc_timer_reg_val[i], sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
141
142 writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 2],
143 sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
144 writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 1],
145 sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
146
147 writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
148 BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
149 }
150
151 static struct clock_event_device __percpu *sirfsoc_clockevent;
152
153 static struct clocksource sirfsoc_clocksource = {
154 .name = "sirfsoc_clocksource",
155 .rating = 200,
156 .mask = CLOCKSOURCE_MASK(64),
157 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
158 .read = sirfsoc_timer_read,
159 .suspend = sirfsoc_clocksource_suspend,
160 .resume = sirfsoc_clocksource_resume,
161 };
162
163 static struct irqaction sirfsoc_timer_irq = {
164 .name = "sirfsoc_timer0",
165 .flags = IRQF_TIMER | IRQF_NOBALANCING,
166 .handler = sirfsoc_timer_interrupt,
167 };
168
169 static struct irqaction sirfsoc_timer1_irq = {
170 .name = "sirfsoc_timer1",
171 .flags = IRQF_TIMER | IRQF_NOBALANCING,
172 .handler = sirfsoc_timer_interrupt,
173 };
174
sirfsoc_local_timer_starting_cpu(unsigned int cpu)175 static int sirfsoc_local_timer_starting_cpu(unsigned int cpu)
176 {
177 struct clock_event_device *ce = per_cpu_ptr(sirfsoc_clockevent, cpu);
178 struct irqaction *action;
179
180 if (cpu == 0)
181 action = &sirfsoc_timer_irq;
182 else
183 action = &sirfsoc_timer1_irq;
184
185 ce->irq = action->irq;
186 ce->name = "local_timer";
187 ce->features = CLOCK_EVT_FEAT_ONESHOT;
188 ce->rating = 200;
189 ce->set_state_shutdown = sirfsoc_timer_shutdown;
190 ce->set_state_oneshot = sirfsoc_timer_shutdown;
191 ce->tick_resume = sirfsoc_timer_shutdown;
192 ce->set_next_event = sirfsoc_timer_set_next_event;
193 clockevents_calc_mult_shift(ce, atlas7_timer_rate, 60);
194 ce->max_delta_ns = clockevent_delta2ns(-2, ce);
195 ce->max_delta_ticks = (unsigned long)-2;
196 ce->min_delta_ns = clockevent_delta2ns(2, ce);
197 ce->min_delta_ticks = 2;
198 ce->cpumask = cpumask_of(cpu);
199
200 action->dev_id = ce;
201 BUG_ON(setup_irq(ce->irq, action));
202 irq_force_affinity(action->irq, cpumask_of(cpu));
203
204 clockevents_register_device(ce);
205 return 0;
206 }
207
sirfsoc_local_timer_dying_cpu(unsigned int cpu)208 static int sirfsoc_local_timer_dying_cpu(unsigned int cpu)
209 {
210 sirfsoc_timer_count_disable(1);
211
212 if (cpu == 0)
213 remove_irq(sirfsoc_timer_irq.irq, &sirfsoc_timer_irq);
214 else
215 remove_irq(sirfsoc_timer1_irq.irq, &sirfsoc_timer1_irq);
216 return 0;
217 }
218
sirfsoc_clockevent_init(void)219 static int __init sirfsoc_clockevent_init(void)
220 {
221 sirfsoc_clockevent = alloc_percpu(struct clock_event_device);
222 BUG_ON(!sirfsoc_clockevent);
223
224 /* Install and invoke hotplug callbacks */
225 return cpuhp_setup_state(CPUHP_AP_MARCO_TIMER_STARTING,
226 "clockevents/marco:starting",
227 sirfsoc_local_timer_starting_cpu,
228 sirfsoc_local_timer_dying_cpu);
229 }
230
231 /* initialize the kernel jiffy timer source */
sirfsoc_atlas7_timer_init(struct device_node * np)232 static int __init sirfsoc_atlas7_timer_init(struct device_node *np)
233 {
234 struct clk *clk;
235
236 clk = of_clk_get(np, 0);
237 BUG_ON(IS_ERR(clk));
238
239 BUG_ON(clk_prepare_enable(clk));
240
241 atlas7_timer_rate = clk_get_rate(clk);
242
243 /* timer dividers: 0, not divided */
244 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
245 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL);
246 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_1_CTRL);
247
248 /* Initialize timer counters to 0 */
249 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
250 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
251 writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
252 BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
253 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0);
254 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_1);
255
256 /* Clear all interrupts */
257 writel_relaxed(0xFFFF, sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);
258
259 BUG_ON(clocksource_register_hz(&sirfsoc_clocksource, atlas7_timer_rate));
260
261 return sirfsoc_clockevent_init();
262 }
263
sirfsoc_of_timer_init(struct device_node * np)264 static int __init sirfsoc_of_timer_init(struct device_node *np)
265 {
266 sirfsoc_timer_base = of_iomap(np, 0);
267 if (!sirfsoc_timer_base) {
268 pr_err("unable to map timer cpu registers\n");
269 return -ENXIO;
270 }
271
272 sirfsoc_timer_irq.irq = irq_of_parse_and_map(np, 0);
273 if (!sirfsoc_timer_irq.irq) {
274 pr_err("No irq passed for timer0 via DT\n");
275 return -EINVAL;
276 }
277
278 sirfsoc_timer1_irq.irq = irq_of_parse_and_map(np, 1);
279 if (!sirfsoc_timer1_irq.irq) {
280 pr_err("No irq passed for timer1 via DT\n");
281 return -EINVAL;
282 }
283
284 return sirfsoc_atlas7_timer_init(np);
285 }
286 TIMER_OF_DECLARE(sirfsoc_atlas7_timer, "sirf,atlas7-tick", sirfsoc_of_timer_init);
287
