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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> | |
137c6b3c | 22 | #include <linux/sched_clock.h> |
b2ac5d75 MR |
23 | #include <linux/of.h> |
24 | #include <linux/of_address.h> | |
25 | #include <linux/of_irq.h> | |
b2ac5d75 | 26 | |
04981731 | 27 | #define TIMER_IRQ_EN_REG 0x00 |
40777645 | 28 | #define TIMER_IRQ_EN(val) BIT(val) |
b2ac5d75 | 29 | #define TIMER_IRQ_ST_REG 0x04 |
04981731 | 30 | #define TIMER_CTL_REG(val) (0x10 * val + 0x10) |
40777645 | 31 | #define TIMER_CTL_ENABLE BIT(0) |
9eded232 | 32 | #define TIMER_CTL_RELOAD BIT(1) |
a2c49e7b MR |
33 | #define TIMER_CTL_CLK_SRC(val) (((val) & 0x3) << 2) |
34 | #define TIMER_CTL_CLK_SRC_OSC24M (1) | |
35 | #define TIMER_CTL_CLK_PRES(val) (((val) & 0x7) << 4) | |
40777645 | 36 | #define TIMER_CTL_ONESHOT BIT(7) |
bb008b9e MR |
37 | #define TIMER_INTVAL_REG(val) (0x10 * (val) + 0x14) |
38 | #define TIMER_CNTVAL_REG(val) (0x10 * (val) + 0x18) | |
b2ac5d75 | 39 | |
12e1480b MR |
40 | #define TIMER_SYNC_TICKS 3 |
41 | ||
b2ac5d75 | 42 | static void __iomem *timer_base; |
7e141834 | 43 | static u32 ticks_per_jiffy; |
b2ac5d75 | 44 | |
63d88f1a MR |
45 | /* |
46 | * When we disable a timer, we need to wait at least for 2 cycles of | |
47 | * the timer source clock. We will use for that the clocksource timer | |
48 | * that is already setup and runs at the same frequency than the other | |
49 | * timers, and we never will be disabled. | |
50 | */ | |
51 | static void sun4i_clkevt_sync(void) | |
52 | { | |
53 | u32 old = readl(timer_base + TIMER_CNTVAL_REG(1)); | |
54 | ||
12e1480b | 55 | while ((old - readl(timer_base + TIMER_CNTVAL_REG(1))) < TIMER_SYNC_TICKS) |
63d88f1a MR |
56 | cpu_relax(); |
57 | } | |
58 | ||
96651a07 MR |
59 | static void sun4i_clkevt_time_stop(u8 timer) |
60 | { | |
61 | u32 val = readl(timer_base + TIMER_CTL_REG(timer)); | |
62 | writel(val & ~TIMER_CTL_ENABLE, timer_base + TIMER_CTL_REG(timer)); | |
63 | sun4i_clkevt_sync(); | |
64 | } | |
65 | ||
66 | static void sun4i_clkevt_time_setup(u8 timer, unsigned long delay) | |
67 | { | |
68 | writel(delay, timer_base + TIMER_INTVAL_REG(timer)); | |
69 | } | |
70 | ||
71 | static void sun4i_clkevt_time_start(u8 timer, bool periodic) | |
72 | { | |
73 | u32 val = readl(timer_base + TIMER_CTL_REG(timer)); | |
74 | ||
75 | if (periodic) | |
76 | val &= ~TIMER_CTL_ONESHOT; | |
77 | else | |
78 | val |= TIMER_CTL_ONESHOT; | |
79 | ||
7e141834 MR |
80 | writel(val | TIMER_CTL_ENABLE | TIMER_CTL_RELOAD, |
81 | timer_base + TIMER_CTL_REG(timer)); | |
96651a07 MR |
82 | } |
83 | ||
119fd635 | 84 | static void sun4i_clkevt_mode(enum clock_event_mode mode, |
b2ac5d75 MR |
85 | struct clock_event_device *clk) |
86 | { | |
b2ac5d75 MR |
87 | switch (mode) { |
88 | case CLOCK_EVT_MODE_PERIODIC: | |
96651a07 | 89 | sun4i_clkevt_time_stop(0); |
7e141834 | 90 | sun4i_clkevt_time_setup(0, ticks_per_jiffy); |
96651a07 | 91 | sun4i_clkevt_time_start(0, true); |
b2ac5d75 | 92 | break; |
b2ac5d75 | 93 | case CLOCK_EVT_MODE_ONESHOT: |
96651a07 MR |
94 | sun4i_clkevt_time_stop(0); |
95 | sun4i_clkevt_time_start(0, false); | |
b2ac5d75 MR |
96 | break; |
97 | case CLOCK_EVT_MODE_UNUSED: | |
98 | case CLOCK_EVT_MODE_SHUTDOWN: | |
99 | default: | |
96651a07 | 100 | sun4i_clkevt_time_stop(0); |
b2ac5d75 MR |
101 | break; |
102 | } | |
103 | } | |
104 | ||
119fd635 | 105 | static int sun4i_clkevt_next_event(unsigned long evt, |
b2ac5d75 MR |
106 | struct clock_event_device *unused) |
107 | { | |
96651a07 | 108 | sun4i_clkevt_time_stop(0); |
12e1480b | 109 | sun4i_clkevt_time_setup(0, evt - TIMER_SYNC_TICKS); |
96651a07 | 110 | sun4i_clkevt_time_start(0, false); |
b2ac5d75 MR |
111 | |
112 | return 0; | |
113 | } | |
114 | ||
119fd635 MR |
115 | static struct clock_event_device sun4i_clockevent = { |
116 | .name = "sun4i_tick", | |
5df9affb | 117 | .rating = 350, |
b2ac5d75 | 118 | .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, |
119fd635 MR |
119 | .set_mode = sun4i_clkevt_mode, |
120 | .set_next_event = sun4i_clkevt_next_event, | |
b2ac5d75 MR |
121 | }; |
122 | ||
123 | ||
119fd635 | 124 | static irqreturn_t sun4i_timer_interrupt(int irq, void *dev_id) |
b2ac5d75 MR |
125 | { |
126 | struct clock_event_device *evt = (struct clock_event_device *)dev_id; | |
127 | ||
128 | writel(0x1, timer_base + TIMER_IRQ_ST_REG); | |
129 | evt->event_handler(evt); | |
130 | ||
131 | return IRQ_HANDLED; | |
132 | } | |
133 | ||
119fd635 MR |
134 | static struct irqaction sun4i_timer_irq = { |
135 | .name = "sun4i_timer0", | |
3353652c | 136 | .flags = IRQF_TIMER | IRQF_IRQPOLL, |
119fd635 MR |
137 | .handler = sun4i_timer_interrupt, |
138 | .dev_id = &sun4i_clockevent, | |
b2ac5d75 MR |
139 | }; |
140 | ||
662e7230 | 141 | static u64 notrace sun4i_timer_sched_read(void) |
137c6b3c MR |
142 | { |
143 | return ~readl(timer_base + TIMER_CNTVAL_REG(1)); | |
144 | } | |
145 | ||
119fd635 | 146 | static void __init sun4i_timer_init(struct device_node *node) |
b2ac5d75 | 147 | { |
b2ac5d75 MR |
148 | unsigned long rate = 0; |
149 | struct clk *clk; | |
150 | int ret, irq; | |
151 | u32 val; | |
152 | ||
b2ac5d75 MR |
153 | timer_base = of_iomap(node, 0); |
154 | if (!timer_base) | |
155 | panic("Can't map registers"); | |
156 | ||
157 | irq = irq_of_parse_and_map(node, 0); | |
158 | if (irq <= 0) | |
159 | panic("Can't parse IRQ"); | |
160 | ||
b2ac5d75 MR |
161 | clk = of_clk_get(node, 0); |
162 | if (IS_ERR(clk)) | |
163 | panic("Can't get timer clock"); | |
8c31bec2 | 164 | clk_prepare_enable(clk); |
b2ac5d75 MR |
165 | |
166 | rate = clk_get_rate(clk); | |
167 | ||
137c6b3c MR |
168 | writel(~0, timer_base + TIMER_INTVAL_REG(1)); |
169 | writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD | | |
170 | TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M), | |
171 | timer_base + TIMER_CTL_REG(1)); | |
172 | ||
662e7230 | 173 | sched_clock_register(sun4i_timer_sched_read, 32, rate); |
137c6b3c | 174 | clocksource_mmio_init(timer_base + TIMER_CNTVAL_REG(1), node->name, |
5df9affb | 175 | rate, 350, 32, clocksource_mmio_readl_down); |
137c6b3c | 176 | |
7e141834 | 177 | ticks_per_jiffy = DIV_ROUND_UP(rate, HZ); |
b2ac5d75 | 178 | |
7e141834 | 179 | writel(TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M), |
a2c49e7b | 180 | timer_base + TIMER_CTL_REG(0)); |
b2ac5d75 | 181 | |
6db50bb6 MZ |
182 | /* Make sure timer is stopped before playing with interrupts */ |
183 | sun4i_clkevt_time_stop(0); | |
184 | ||
119fd635 | 185 | ret = setup_irq(irq, &sun4i_timer_irq); |
b2ac5d75 MR |
186 | if (ret) |
187 | pr_warn("failed to setup irq %d\n", irq); | |
188 | ||
189 | /* Enable timer0 interrupt */ | |
04981731 MR |
190 | val = readl(timer_base + TIMER_IRQ_EN_REG); |
191 | writel(val | TIMER_IRQ_EN(0), timer_base + TIMER_IRQ_EN_REG); | |
b2ac5d75 | 192 | |
2c28f32c | 193 | sun4i_clockevent.cpumask = cpu_possible_mask; |
247f325a | 194 | sun4i_clockevent.irq = irq; |
b2ac5d75 | 195 | |
12e1480b MR |
196 | clockevents_config_and_register(&sun4i_clockevent, rate, |
197 | TIMER_SYNC_TICKS, 0xffffffff); | |
b2ac5d75 | 198 | } |
ec6c085c | 199 | CLOCKSOURCE_OF_DECLARE(sun4i, "allwinner,sun4i-a10-timer", |
119fd635 | 200 | sun4i_timer_init); |