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Binghua Duan02c981c2011-07-08 17:40:12 +08001/*
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/bitops.h>
14#include <linux/irq.h>
15#include <linux/clk.h>
16#include <linux/err.h>
17#include <linux/slab.h>
18#include <linux/of.h>
19#include <linux/of_address.h>
20#include <mach/map.h>
Marc Zyngierbc8d8492012-01-16 11:44:12 +000021#include <asm/sched_clock.h>
Binghua Duan02c981c2011-07-08 17:40:12 +080022#include <asm/mach/time.h>
23
24#define SIRFSOC_TIMER_COUNTER_LO 0x0000
25#define SIRFSOC_TIMER_COUNTER_HI 0x0004
26#define SIRFSOC_TIMER_MATCH_0 0x0008
27#define SIRFSOC_TIMER_MATCH_1 0x000C
28#define SIRFSOC_TIMER_MATCH_2 0x0010
29#define SIRFSOC_TIMER_MATCH_3 0x0014
30#define SIRFSOC_TIMER_MATCH_4 0x0018
31#define SIRFSOC_TIMER_MATCH_5 0x001C
32#define SIRFSOC_TIMER_STATUS 0x0020
33#define SIRFSOC_TIMER_INT_EN 0x0024
34#define SIRFSOC_TIMER_WATCHDOG_EN 0x0028
35#define SIRFSOC_TIMER_DIV 0x002C
36#define SIRFSOC_TIMER_LATCH 0x0030
37#define SIRFSOC_TIMER_LATCHED_LO 0x0034
38#define SIRFSOC_TIMER_LATCHED_HI 0x0038
39
40#define SIRFSOC_TIMER_WDT_INDEX 5
41
42#define SIRFSOC_TIMER_LATCH_BIT BIT(0)
43
Barry Songe5598a82011-09-21 20:56:33 +080044#define SIRFSOC_TIMER_REG_CNT 11
45
46static const u32 sirfsoc_timer_reg_list[SIRFSOC_TIMER_REG_CNT] = {
47 SIRFSOC_TIMER_MATCH_0, SIRFSOC_TIMER_MATCH_1, SIRFSOC_TIMER_MATCH_2,
48 SIRFSOC_TIMER_MATCH_3, SIRFSOC_TIMER_MATCH_4, SIRFSOC_TIMER_MATCH_5,
49 SIRFSOC_TIMER_INT_EN, SIRFSOC_TIMER_WATCHDOG_EN, SIRFSOC_TIMER_DIV,
50 SIRFSOC_TIMER_LATCHED_LO, SIRFSOC_TIMER_LATCHED_HI,
51};
52
53static u32 sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT];
54
Binghua Duan02c981c2011-07-08 17:40:12 +080055static void __iomem *sirfsoc_timer_base;
56static void __init sirfsoc_of_timer_map(void);
57
58/* timer0 interrupt handler */
59static irqreturn_t sirfsoc_timer_interrupt(int irq, void *dev_id)
60{
61 struct clock_event_device *ce = dev_id;
62
63 WARN_ON(!(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_STATUS) & BIT(0)));
64
65 /* clear timer0 interrupt */
66 writel_relaxed(BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_STATUS);
67
68 ce->event_handler(ce);
69
70 return IRQ_HANDLED;
71}
72
73/* read 64-bit timer counter */
74static cycle_t sirfsoc_timer_read(struct clocksource *cs)
75{
76 u64 cycles;
77
78 /* latch the 64-bit timer counter */
79 writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, sirfsoc_timer_base + SIRFSOC_TIMER_LATCH);
80 cycles = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_HI);
81 cycles = (cycles << 32) | readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO);
82
83 return cycles;
84}
85
86static int sirfsoc_timer_set_next_event(unsigned long delta,
87 struct clock_event_device *ce)
88{
89 unsigned long now, next;
90
91 writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, sirfsoc_timer_base + SIRFSOC_TIMER_LATCH);
92 now = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO);
93 next = now + delta;
94 writel_relaxed(next, sirfsoc_timer_base + SIRFSOC_TIMER_MATCH_0);
95 writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, sirfsoc_timer_base + SIRFSOC_TIMER_LATCH);
96 now = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO);
97
98 return next - now > delta ? -ETIME : 0;
99}
100
101static void sirfsoc_timer_set_mode(enum clock_event_mode mode,
102 struct clock_event_device *ce)
103{
104 u32 val = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN);
105 switch (mode) {
106 case CLOCK_EVT_MODE_PERIODIC:
107 WARN_ON(1);
108 break;
109 case CLOCK_EVT_MODE_ONESHOT:
110 writel_relaxed(val | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN);
111 break;
112 case CLOCK_EVT_MODE_SHUTDOWN:
113 writel_relaxed(val & ~BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN);
114 break;
115 case CLOCK_EVT_MODE_UNUSED:
116 case CLOCK_EVT_MODE_RESUME:
117 break;
118 }
119}
120
Barry Songe5598a82011-09-21 20:56:33 +0800121static void sirfsoc_clocksource_suspend(struct clocksource *cs)
122{
123 int i;
124
125 writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, sirfsoc_timer_base + SIRFSOC_TIMER_LATCH);
126
127 for (i = 0; i < SIRFSOC_TIMER_REG_CNT; i++)
128 sirfsoc_timer_reg_val[i] = readl_relaxed(sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
129}
130
131static void sirfsoc_clocksource_resume(struct clocksource *cs)
132{
133 int i;
134
135 for (i = 0; i < SIRFSOC_TIMER_REG_CNT; i++)
136 writel_relaxed(sirfsoc_timer_reg_val[i], sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
137
138 writel_relaxed(sirfsoc_timer_reg_val[i - 2], sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_LO);
139 writel_relaxed(sirfsoc_timer_reg_val[i - 1], sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_HI);
140}
141
Binghua Duan02c981c2011-07-08 17:40:12 +0800142static struct clock_event_device sirfsoc_clockevent = {
143 .name = "sirfsoc_clockevent",
144 .rating = 200,
145 .features = CLOCK_EVT_FEAT_ONESHOT,
146 .set_mode = sirfsoc_timer_set_mode,
147 .set_next_event = sirfsoc_timer_set_next_event,
148};
149
150static struct clocksource sirfsoc_clocksource = {
151 .name = "sirfsoc_clocksource",
152 .rating = 200,
153 .mask = CLOCKSOURCE_MASK(64),
154 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
155 .read = sirfsoc_timer_read,
Barry Songe5598a82011-09-21 20:56:33 +0800156 .suspend = sirfsoc_clocksource_suspend,
157 .resume = sirfsoc_clocksource_resume,
Binghua Duan02c981c2011-07-08 17:40:12 +0800158};
159
160static struct irqaction sirfsoc_timer_irq = {
161 .name = "sirfsoc_timer0",
162 .flags = IRQF_TIMER,
163 .irq = 0,
164 .handler = sirfsoc_timer_interrupt,
165 .dev_id = &sirfsoc_clockevent,
166};
167
168/* Overwrite weak default sched_clock with more precise one */
Marc Zyngierbc8d8492012-01-16 11:44:12 +0000169static u32 notrace sirfsoc_read_sched_clock(void)
Binghua Duan02c981c2011-07-08 17:40:12 +0800170{
Marc Zyngierbc8d8492012-01-16 11:44:12 +0000171 return (u32)(sirfsoc_timer_read(NULL) & 0xffffffff);
Binghua Duan02c981c2011-07-08 17:40:12 +0800172}
173
174static void __init sirfsoc_clockevent_init(void)
175{
176 clockevents_calc_mult_shift(&sirfsoc_clockevent, CLOCK_TICK_RATE, 60);
177
178 sirfsoc_clockevent.max_delta_ns =
179 clockevent_delta2ns(-2, &sirfsoc_clockevent);
180 sirfsoc_clockevent.min_delta_ns =
181 clockevent_delta2ns(2, &sirfsoc_clockevent);
182
183 sirfsoc_clockevent.cpumask = cpumask_of(0);
184 clockevents_register_device(&sirfsoc_clockevent);
185}
186
187/* initialize the kernel jiffy timer source */
188static void __init sirfsoc_timer_init(void)
189{
190 unsigned long rate;
191
192 /* timer's input clock is io clock */
193 struct clk *clk = clk_get_sys("io", NULL);
194
195 BUG_ON(IS_ERR(clk));
196
197 rate = clk_get_rate(clk);
198
199 BUG_ON(rate < CLOCK_TICK_RATE);
200 BUG_ON(rate % CLOCK_TICK_RATE);
201
Marc Zyngierbc8d8492012-01-16 11:44:12 +0000202 sirfsoc_of_timer_map();
203
Binghua Duan02c981c2011-07-08 17:40:12 +0800204 writel_relaxed(rate / CLOCK_TICK_RATE / 2 - 1, sirfsoc_timer_base + SIRFSOC_TIMER_DIV);
205 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_LO);
206 writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_HI);
207 writel_relaxed(BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_STATUS);
208
209 BUG_ON(clocksource_register_hz(&sirfsoc_clocksource, CLOCK_TICK_RATE));
210
Marc Zyngierbc8d8492012-01-16 11:44:12 +0000211 setup_sched_clock(sirfsoc_read_sched_clock, 32, CLOCK_TICK_RATE);
212
Binghua Duan02c981c2011-07-08 17:40:12 +0800213 BUG_ON(setup_irq(sirfsoc_timer_irq.irq, &sirfsoc_timer_irq));
214
215 sirfsoc_clockevent_init();
216}
217
218static struct of_device_id timer_ids[] = {
219 { .compatible = "sirf,prima2-tick" },
Jamie Iles6a537472011-08-01 21:09:36 +0100220 {},
Binghua Duan02c981c2011-07-08 17:40:12 +0800221};
222
223static void __init sirfsoc_of_timer_map(void)
224{
225 struct device_node *np;
226 const unsigned int *intspec;
227
228 np = of_find_matching_node(NULL, timer_ids);
229 if (!np)
230 panic("unable to find compatible timer node in dtb\n");
231 sirfsoc_timer_base = of_iomap(np, 0);
232 if (!sirfsoc_timer_base)
233 panic("unable to map timer cpu registers\n");
234
235 /* Get the interrupts property */
236 intspec = of_get_property(np, "interrupts", NULL);
237 BUG_ON(!intspec);
238 sirfsoc_timer_irq.irq = be32_to_cpup(intspec);
239
240 of_node_put(np);
241}
242
243struct sys_timer sirfsoc_timer = {
244 .init = sirfsoc_timer_init,
245};