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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/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> | |
bc8d849d | 21 | #include <asm/sched_clock.h> |
02c981c0 BD |
22 | #include <asm/mach/time.h> |
23 | ||
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24 | #include "common.h" |
25 | ||
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26 | #define SIRFSOC_TIMER_COUNTER_LO 0x0000 |
27 | #define SIRFSOC_TIMER_COUNTER_HI 0x0004 | |
28 | #define SIRFSOC_TIMER_MATCH_0 0x0008 | |
29 | #define SIRFSOC_TIMER_MATCH_1 0x000C | |
30 | #define SIRFSOC_TIMER_MATCH_2 0x0010 | |
31 | #define SIRFSOC_TIMER_MATCH_3 0x0014 | |
32 | #define SIRFSOC_TIMER_MATCH_4 0x0018 | |
33 | #define SIRFSOC_TIMER_MATCH_5 0x001C | |
34 | #define SIRFSOC_TIMER_STATUS 0x0020 | |
35 | #define SIRFSOC_TIMER_INT_EN 0x0024 | |
36 | #define SIRFSOC_TIMER_WATCHDOG_EN 0x0028 | |
37 | #define SIRFSOC_TIMER_DIV 0x002C | |
38 | #define SIRFSOC_TIMER_LATCH 0x0030 | |
39 | #define SIRFSOC_TIMER_LATCHED_LO 0x0034 | |
40 | #define SIRFSOC_TIMER_LATCHED_HI 0x0038 | |
41 | ||
42 | #define SIRFSOC_TIMER_WDT_INDEX 5 | |
43 | ||
44 | #define SIRFSOC_TIMER_LATCH_BIT BIT(0) | |
45 | ||
e5598a85 BS |
46 | #define SIRFSOC_TIMER_REG_CNT 11 |
47 | ||
48 | static const u32 sirfsoc_timer_reg_list[SIRFSOC_TIMER_REG_CNT] = { | |
49 | SIRFSOC_TIMER_MATCH_0, SIRFSOC_TIMER_MATCH_1, SIRFSOC_TIMER_MATCH_2, | |
50 | SIRFSOC_TIMER_MATCH_3, SIRFSOC_TIMER_MATCH_4, SIRFSOC_TIMER_MATCH_5, | |
51 | SIRFSOC_TIMER_INT_EN, SIRFSOC_TIMER_WATCHDOG_EN, SIRFSOC_TIMER_DIV, | |
52 | SIRFSOC_TIMER_LATCHED_LO, SIRFSOC_TIMER_LATCHED_HI, | |
53 | }; | |
54 | ||
55 | static u32 sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT]; | |
56 | ||
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57 | static void __iomem *sirfsoc_timer_base; |
58 | static void __init sirfsoc_of_timer_map(void); | |
59 | ||
60 | /* timer0 interrupt handler */ | |
61 | static irqreturn_t sirfsoc_timer_interrupt(int irq, void *dev_id) | |
62 | { | |
63 | struct clock_event_device *ce = dev_id; | |
64 | ||
65 | WARN_ON(!(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_STATUS) & BIT(0))); | |
66 | ||
67 | /* clear timer0 interrupt */ | |
68 | writel_relaxed(BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_STATUS); | |
69 | ||
70 | ce->event_handler(ce); | |
71 | ||
72 | return IRQ_HANDLED; | |
73 | } | |
74 | ||
75 | /* read 64-bit timer counter */ | |
76 | static cycle_t sirfsoc_timer_read(struct clocksource *cs) | |
77 | { | |
78 | u64 cycles; | |
79 | ||
80 | /* latch the 64-bit timer counter */ | |
81 | writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, sirfsoc_timer_base + SIRFSOC_TIMER_LATCH); | |
82 | cycles = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_HI); | |
83 | cycles = (cycles << 32) | readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO); | |
84 | ||
85 | return cycles; | |
86 | } | |
87 | ||
88 | static int sirfsoc_timer_set_next_event(unsigned long delta, | |
89 | struct clock_event_device *ce) | |
90 | { | |
91 | unsigned long now, next; | |
92 | ||
93 | writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, sirfsoc_timer_base + SIRFSOC_TIMER_LATCH); | |
94 | now = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO); | |
95 | next = now + delta; | |
96 | writel_relaxed(next, sirfsoc_timer_base + SIRFSOC_TIMER_MATCH_0); | |
97 | writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, sirfsoc_timer_base + SIRFSOC_TIMER_LATCH); | |
98 | now = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO); | |
99 | ||
100 | return next - now > delta ? -ETIME : 0; | |
101 | } | |
102 | ||
103 | static void sirfsoc_timer_set_mode(enum clock_event_mode mode, | |
104 | struct clock_event_device *ce) | |
105 | { | |
106 | u32 val = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN); | |
107 | switch (mode) { | |
108 | case CLOCK_EVT_MODE_PERIODIC: | |
109 | WARN_ON(1); | |
110 | break; | |
111 | case CLOCK_EVT_MODE_ONESHOT: | |
112 | writel_relaxed(val | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN); | |
113 | break; | |
114 | case CLOCK_EVT_MODE_SHUTDOWN: | |
115 | writel_relaxed(val & ~BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN); | |
116 | break; | |
117 | case CLOCK_EVT_MODE_UNUSED: | |
118 | case CLOCK_EVT_MODE_RESUME: | |
119 | break; | |
120 | } | |
121 | } | |
122 | ||
e5598a85 BS |
123 | static void sirfsoc_clocksource_suspend(struct clocksource *cs) |
124 | { | |
125 | int i; | |
126 | ||
127 | writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, sirfsoc_timer_base + SIRFSOC_TIMER_LATCH); | |
128 | ||
129 | for (i = 0; i < SIRFSOC_TIMER_REG_CNT; i++) | |
130 | sirfsoc_timer_reg_val[i] = readl_relaxed(sirfsoc_timer_base + sirfsoc_timer_reg_list[i]); | |
131 | } | |
132 | ||
133 | static void sirfsoc_clocksource_resume(struct clocksource *cs) | |
134 | { | |
135 | int i; | |
136 | ||
debeaf6c | 137 | for (i = 0; i < SIRFSOC_TIMER_REG_CNT - 2; i++) |
e5598a85 BS |
138 | writel_relaxed(sirfsoc_timer_reg_val[i], sirfsoc_timer_base + sirfsoc_timer_reg_list[i]); |
139 | ||
debeaf6c BS |
140 | writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 2], sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_LO); |
141 | writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 1], sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_HI); | |
e5598a85 BS |
142 | } |
143 | ||
02c981c0 BD |
144 | static struct clock_event_device sirfsoc_clockevent = { |
145 | .name = "sirfsoc_clockevent", | |
146 | .rating = 200, | |
147 | .features = CLOCK_EVT_FEAT_ONESHOT, | |
148 | .set_mode = sirfsoc_timer_set_mode, | |
149 | .set_next_event = sirfsoc_timer_set_next_event, | |
150 | }; | |
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, | |
e5598a85 BS |
158 | .suspend = sirfsoc_clocksource_suspend, |
159 | .resume = sirfsoc_clocksource_resume, | |
02c981c0 BD |
160 | }; |
161 | ||
162 | static struct irqaction sirfsoc_timer_irq = { | |
163 | .name = "sirfsoc_timer0", | |
164 | .flags = IRQF_TIMER, | |
165 | .irq = 0, | |
166 | .handler = sirfsoc_timer_interrupt, | |
167 | .dev_id = &sirfsoc_clockevent, | |
168 | }; | |
169 | ||
170 | /* Overwrite weak default sched_clock with more precise one */ | |
bc8d849d | 171 | static u32 notrace sirfsoc_read_sched_clock(void) |
02c981c0 | 172 | { |
bc8d849d | 173 | return (u32)(sirfsoc_timer_read(NULL) & 0xffffffff); |
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174 | } |
175 | ||
176 | static void __init sirfsoc_clockevent_init(void) | |
177 | { | |
178 | clockevents_calc_mult_shift(&sirfsoc_clockevent, CLOCK_TICK_RATE, 60); | |
179 | ||
180 | sirfsoc_clockevent.max_delta_ns = | |
181 | clockevent_delta2ns(-2, &sirfsoc_clockevent); | |
182 | sirfsoc_clockevent.min_delta_ns = | |
183 | clockevent_delta2ns(2, &sirfsoc_clockevent); | |
184 | ||
185 | sirfsoc_clockevent.cpumask = cpumask_of(0); | |
186 | clockevents_register_device(&sirfsoc_clockevent); | |
187 | } | |
188 | ||
189 | /* initialize the kernel jiffy timer source */ | |
6bb27d73 | 190 | void __init sirfsoc_timer_init(void) |
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191 | { |
192 | unsigned long rate; | |
198678b0 BD |
193 | struct clk *clk; |
194 | ||
195 | /* initialize clocking early, we want to set the OS timer */ | |
196 | sirfsoc_of_clk_init(); | |
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197 | |
198 | /* timer's input clock is io clock */ | |
198678b0 | 199 | clk = clk_get_sys("io", NULL); |
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200 | |
201 | BUG_ON(IS_ERR(clk)); | |
202 | ||
203 | rate = clk_get_rate(clk); | |
204 | ||
205 | BUG_ON(rate < CLOCK_TICK_RATE); | |
206 | BUG_ON(rate % CLOCK_TICK_RATE); | |
207 | ||
bc8d849d MZ |
208 | sirfsoc_of_timer_map(); |
209 | ||
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210 | writel_relaxed(rate / CLOCK_TICK_RATE / 2 - 1, sirfsoc_timer_base + SIRFSOC_TIMER_DIV); |
211 | writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_LO); | |
212 | writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_HI); | |
213 | writel_relaxed(BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_STATUS); | |
214 | ||
215 | BUG_ON(clocksource_register_hz(&sirfsoc_clocksource, CLOCK_TICK_RATE)); | |
216 | ||
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217 | setup_sched_clock(sirfsoc_read_sched_clock, 32, CLOCK_TICK_RATE); |
218 | ||
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219 | BUG_ON(setup_irq(sirfsoc_timer_irq.irq, &sirfsoc_timer_irq)); |
220 | ||
221 | sirfsoc_clockevent_init(); | |
222 | } | |
223 | ||
224 | static struct of_device_id timer_ids[] = { | |
225 | { .compatible = "sirf,prima2-tick" }, | |
6a53747b | 226 | {}, |
02c981c0 BD |
227 | }; |
228 | ||
6bb27d73 | 229 | void __init sirfsoc_of_timer_map(void) |
02c981c0 BD |
230 | { |
231 | struct device_node *np; | |
232 | const unsigned int *intspec; | |
233 | ||
234 | np = of_find_matching_node(NULL, timer_ids); | |
235 | if (!np) | |
236 | panic("unable to find compatible timer node in dtb\n"); | |
237 | sirfsoc_timer_base = of_iomap(np, 0); | |
238 | if (!sirfsoc_timer_base) | |
239 | panic("unable to map timer cpu registers\n"); | |
240 | ||
241 | /* Get the interrupts property */ | |
242 | intspec = of_get_property(np, "interrupts", NULL); | |
243 | BUG_ON(!intspec); | |
244 | sirfsoc_timer_irq.irq = be32_to_cpup(intspec); | |
245 | ||
246 | of_node_put(np); | |
247 | } |