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b2ac5d75 MR |
1 | /* |
2 | * Allwinner A1X SoCs timer handling. | |
3 | * | |
4 | * Copyright (C) 2012 Maxime Ripard | |
5 | * | |
6 | * Maxime Ripard <maxime.ripard@free-electrons.com> | |
7 | * | |
8 | * Based on code from | |
9 | * Allwinner Technology Co., Ltd. <www.allwinnertech.com> | |
10 | * Benn Huang <benn@allwinnertech.com> | |
11 | * | |
12 | * This file is licensed under the terms of the GNU General Public | |
13 | * License version 2. This program is licensed "as is" without any | |
14 | * warranty of any kind, whether express or implied. | |
15 | */ | |
16 | ||
17 | #include <linux/clk.h> | |
18 | #include <linux/clockchips.h> | |
19 | #include <linux/interrupt.h> | |
20 | #include <linux/irq.h> | |
21 | #include <linux/irqreturn.h> | |
22 | #include <linux/of.h> | |
23 | #include <linux/of_address.h> | |
24 | #include <linux/of_irq.h> | |
25 | #include <linux/sunxi_timer.h> | |
26 | #include <linux/clk/sunxi.h> | |
27 | ||
28 | #define TIMER_CTL_REG 0x00 | |
29 | #define TIMER_CTL_ENABLE (1 << 0) | |
30 | #define TIMER_IRQ_ST_REG 0x04 | |
31 | #define TIMER0_CTL_REG 0x10 | |
32 | #define TIMER0_CTL_ENABLE (1 << 0) | |
33 | #define TIMER0_CTL_AUTORELOAD (1 << 1) | |
34 | #define TIMER0_CTL_ONESHOT (1 << 7) | |
35 | #define TIMER0_INTVAL_REG 0x14 | |
36 | #define TIMER0_CNTVAL_REG 0x18 | |
37 | ||
38 | #define TIMER_SCAL 16 | |
39 | ||
40 | static void __iomem *timer_base; | |
41 | ||
42 | static void sunxi_clkevt_mode(enum clock_event_mode mode, | |
43 | struct clock_event_device *clk) | |
44 | { | |
45 | u32 u = readl(timer_base + TIMER0_CTL_REG); | |
46 | ||
47 | switch (mode) { | |
48 | case CLOCK_EVT_MODE_PERIODIC: | |
49 | u &= ~(TIMER0_CTL_ONESHOT); | |
50 | writel(u | TIMER0_CTL_ENABLE, timer_base + TIMER0_CTL_REG); | |
51 | break; | |
52 | ||
53 | case CLOCK_EVT_MODE_ONESHOT: | |
54 | writel(u | TIMER0_CTL_ONESHOT, timer_base + TIMER0_CTL_REG); | |
55 | break; | |
56 | case CLOCK_EVT_MODE_UNUSED: | |
57 | case CLOCK_EVT_MODE_SHUTDOWN: | |
58 | default: | |
59 | writel(u & ~(TIMER0_CTL_ENABLE), timer_base + TIMER0_CTL_REG); | |
60 | break; | |
61 | } | |
62 | } | |
63 | ||
64 | static int sunxi_clkevt_next_event(unsigned long evt, | |
65 | struct clock_event_device *unused) | |
66 | { | |
67 | u32 u = readl(timer_base + TIMER0_CTL_REG); | |
68 | writel(evt, timer_base + TIMER0_CNTVAL_REG); | |
69 | writel(u | TIMER0_CTL_ENABLE | TIMER0_CTL_AUTORELOAD, | |
70 | timer_base + TIMER0_CTL_REG); | |
71 | ||
72 | return 0; | |
73 | } | |
74 | ||
75 | static struct clock_event_device sunxi_clockevent = { | |
76 | .name = "sunxi_tick", | |
77 | .shift = 32, | |
78 | .rating = 300, | |
79 | .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, | |
80 | .set_mode = sunxi_clkevt_mode, | |
81 | .set_next_event = sunxi_clkevt_next_event, | |
82 | }; | |
83 | ||
84 | ||
85 | static irqreturn_t sunxi_timer_interrupt(int irq, void *dev_id) | |
86 | { | |
87 | struct clock_event_device *evt = (struct clock_event_device *)dev_id; | |
88 | ||
89 | writel(0x1, timer_base + TIMER_IRQ_ST_REG); | |
90 | evt->event_handler(evt); | |
91 | ||
92 | return IRQ_HANDLED; | |
93 | } | |
94 | ||
95 | static struct irqaction sunxi_timer_irq = { | |
96 | .name = "sunxi_timer0", | |
97 | .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, | |
98 | .handler = sunxi_timer_interrupt, | |
99 | .dev_id = &sunxi_clockevent, | |
100 | }; | |
101 | ||
102 | static struct of_device_id sunxi_timer_dt_ids[] = { | |
103 | { .compatible = "allwinner,sunxi-timer" }, | |
104 | }; | |
105 | ||
106 | static void __init sunxi_timer_init(void) | |
107 | { | |
108 | struct device_node *node; | |
109 | unsigned long rate = 0; | |
110 | struct clk *clk; | |
111 | int ret, irq; | |
112 | u32 val; | |
113 | ||
114 | node = of_find_matching_node(NULL, sunxi_timer_dt_ids); | |
115 | if (!node) | |
116 | panic("No sunxi timer node"); | |
117 | ||
118 | timer_base = of_iomap(node, 0); | |
119 | if (!timer_base) | |
120 | panic("Can't map registers"); | |
121 | ||
122 | irq = irq_of_parse_and_map(node, 0); | |
123 | if (irq <= 0) | |
124 | panic("Can't parse IRQ"); | |
125 | ||
126 | sunxi_init_clocks(); | |
127 | ||
128 | clk = of_clk_get(node, 0); | |
129 | if (IS_ERR(clk)) | |
130 | panic("Can't get timer clock"); | |
131 | ||
132 | rate = clk_get_rate(clk); | |
133 | ||
134 | writel(rate / (TIMER_SCAL * HZ), | |
135 | timer_base + TIMER0_INTVAL_REG); | |
136 | ||
137 | /* set clock source to HOSC, 16 pre-division */ | |
138 | val = readl(timer_base + TIMER0_CTL_REG); | |
139 | val &= ~(0x07 << 4); | |
140 | val &= ~(0x03 << 2); | |
141 | val |= (4 << 4) | (1 << 2); | |
142 | writel(val, timer_base + TIMER0_CTL_REG); | |
143 | ||
144 | /* set mode to auto reload */ | |
145 | val = readl(timer_base + TIMER0_CTL_REG); | |
146 | writel(val | TIMER0_CTL_AUTORELOAD, timer_base + TIMER0_CTL_REG); | |
147 | ||
148 | ret = setup_irq(irq, &sunxi_timer_irq); | |
149 | if (ret) | |
150 | pr_warn("failed to setup irq %d\n", irq); | |
151 | ||
152 | /* Enable timer0 interrupt */ | |
153 | val = readl(timer_base + TIMER_CTL_REG); | |
154 | writel(val | TIMER_CTL_ENABLE, timer_base + TIMER_CTL_REG); | |
155 | ||
156 | sunxi_clockevent.mult = div_sc(rate / TIMER_SCAL, | |
157 | NSEC_PER_SEC, | |
158 | sunxi_clockevent.shift); | |
159 | sunxi_clockevent.max_delta_ns = clockevent_delta2ns(0xff, | |
160 | &sunxi_clockevent); | |
161 | sunxi_clockevent.min_delta_ns = clockevent_delta2ns(0x1, | |
162 | &sunxi_clockevent); | |
163 | sunxi_clockevent.cpumask = cpumask_of(0); | |
164 | ||
165 | clockevents_register_device(&sunxi_clockevent); | |
166 | } | |
167 | ||
168 | struct sys_timer sunxi_timer = { | |
169 | .init = sunxi_timer_init, | |
170 | }; |