1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2017 Spreadtrum Communications Inc.
4  */
5 
6 #include <linux/init.h>
7 #include <linux/interrupt.h>
8 
9 #include "timer-of.h"
10 
11 #define TIMER_NAME		"sprd_timer"
12 
13 #define TIMER_LOAD_LO		0x0
14 #define TIMER_LOAD_HI		0x4
15 #define TIMER_VALUE_LO		0x8
16 #define TIMER_VALUE_HI		0xc
17 
18 #define TIMER_CTL		0x10
19 #define TIMER_CTL_PERIOD_MODE	BIT(0)
20 #define TIMER_CTL_ENABLE	BIT(1)
21 #define TIMER_CTL_64BIT_WIDTH	BIT(16)
22 
23 #define TIMER_INT		0x14
24 #define TIMER_INT_EN		BIT(0)
25 #define TIMER_INT_RAW_STS	BIT(1)
26 #define TIMER_INT_MASK_STS	BIT(2)
27 #define TIMER_INT_CLR		BIT(3)
28 
29 #define TIMER_VALUE_SHDW_LO	0x18
30 #define TIMER_VALUE_SHDW_HI	0x1c
31 
32 #define TIMER_VALUE_LO_MASK	GENMASK(31, 0)
33 
34 static void sprd_timer_enable(void __iomem *base, u32 flag)
35 {
36 	u32 val = readl_relaxed(base + TIMER_CTL);
37 
38 	val |= TIMER_CTL_ENABLE;
39 	if (flag & TIMER_CTL_64BIT_WIDTH)
40 		val |= TIMER_CTL_64BIT_WIDTH;
41 	else
42 		val &= ~TIMER_CTL_64BIT_WIDTH;
43 
44 	if (flag & TIMER_CTL_PERIOD_MODE)
45 		val |= TIMER_CTL_PERIOD_MODE;
46 	else
47 		val &= ~TIMER_CTL_PERIOD_MODE;
48 
49 	writel_relaxed(val, base + TIMER_CTL);
50 }
51 
52 static void sprd_timer_disable(void __iomem *base)
53 {
54 	u32 val = readl_relaxed(base + TIMER_CTL);
55 
56 	val &= ~TIMER_CTL_ENABLE;
57 	writel_relaxed(val, base + TIMER_CTL);
58 }
59 
60 static void sprd_timer_update_counter(void __iomem *base, unsigned long cycles)
61 {
62 	writel_relaxed(cycles & TIMER_VALUE_LO_MASK, base + TIMER_LOAD_LO);
63 	writel_relaxed(0, base + TIMER_LOAD_HI);
64 }
65 
66 static void sprd_timer_enable_interrupt(void __iomem *base)
67 {
68 	writel_relaxed(TIMER_INT_EN, base + TIMER_INT);
69 }
70 
71 static void sprd_timer_clear_interrupt(void __iomem *base)
72 {
73 	u32 val = readl_relaxed(base + TIMER_INT);
74 
75 	val |= TIMER_INT_CLR;
76 	writel_relaxed(val, base + TIMER_INT);
77 }
78 
79 static int sprd_timer_set_next_event(unsigned long cycles,
80 				     struct clock_event_device *ce)
81 {
82 	struct timer_of *to = to_timer_of(ce);
83 
84 	sprd_timer_disable(timer_of_base(to));
85 	sprd_timer_update_counter(timer_of_base(to), cycles);
86 	sprd_timer_enable(timer_of_base(to), 0);
87 
88 	return 0;
89 }
90 
91 static int sprd_timer_set_periodic(struct clock_event_device *ce)
92 {
93 	struct timer_of *to = to_timer_of(ce);
94 
95 	sprd_timer_disable(timer_of_base(to));
96 	sprd_timer_update_counter(timer_of_base(to), timer_of_period(to));
97 	sprd_timer_enable(timer_of_base(to), TIMER_CTL_PERIOD_MODE);
98 
99 	return 0;
100 }
101 
102 static int sprd_timer_shutdown(struct clock_event_device *ce)
103 {
104 	struct timer_of *to = to_timer_of(ce);
105 
106 	sprd_timer_disable(timer_of_base(to));
107 	return 0;
108 }
109 
110 static irqreturn_t sprd_timer_interrupt(int irq, void *dev_id)
111 {
112 	struct clock_event_device *ce = (struct clock_event_device *)dev_id;
113 	struct timer_of *to = to_timer_of(ce);
114 
115 	sprd_timer_clear_interrupt(timer_of_base(to));
116 
117 	if (clockevent_state_oneshot(ce))
118 		sprd_timer_disable(timer_of_base(to));
119 
120 	ce->event_handler(ce);
121 	return IRQ_HANDLED;
122 }
123 
124 static struct timer_of to = {
125 	.flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,
126 
127 	.clkevt = {
128 		.name = TIMER_NAME,
129 		.rating = 300,
130 		.features = CLOCK_EVT_FEAT_DYNIRQ | CLOCK_EVT_FEAT_PERIODIC |
131 			CLOCK_EVT_FEAT_ONESHOT,
132 		.set_state_shutdown = sprd_timer_shutdown,
133 		.set_state_periodic = sprd_timer_set_periodic,
134 		.set_next_event = sprd_timer_set_next_event,
135 		.cpumask = cpu_possible_mask,
136 	},
137 
138 	.of_irq = {
139 		.handler = sprd_timer_interrupt,
140 		.flags = IRQF_TIMER | IRQF_IRQPOLL,
141 	},
142 };
143 
144 static int __init sprd_timer_init(struct device_node *np)
145 {
146 	int ret;
147 
148 	ret = timer_of_init(np, &to);
149 	if (ret)
150 		return ret;
151 
152 	sprd_timer_enable_interrupt(timer_of_base(&to));
153 	clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
154 					1, UINT_MAX);
155 
156 	return 0;
157 }
158 
159 TIMER_OF_DECLARE(sc9860_timer, "sprd,sc9860-timer", sprd_timer_init);
160