1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * RDA8810PL SoC timer driver
4  *
5  * Copyright RDA Microelectronics Company Limited
6  * Copyright (c) 2017 Andreas Färber
7  * Copyright (c) 2018 Manivannan Sadhasivam
8  *
9  * RDA8810PL has two independent timers: OSTIMER (56 bit) and HWTIMER (64 bit).
10  * Each timer provides optional interrupt support. In this driver, OSTIMER is
11  * used for clockevents and HWTIMER is used for clocksource.
12  */
13 
14 #include <linux/init.h>
15 #include <linux/interrupt.h>
16 
17 #include "timer-of.h"
18 
19 #define RDA_OSTIMER_LOADVAL_L	0x000
20 #define RDA_OSTIMER_CTRL	0x004
21 #define RDA_HWTIMER_LOCKVAL_L	0x024
22 #define RDA_HWTIMER_LOCKVAL_H	0x028
23 #define RDA_TIMER_IRQ_MASK_SET	0x02c
24 #define RDA_TIMER_IRQ_MASK_CLR	0x030
25 #define RDA_TIMER_IRQ_CLR	0x034
26 
27 #define RDA_OSTIMER_CTRL_ENABLE		BIT(24)
28 #define RDA_OSTIMER_CTRL_REPEAT		BIT(28)
29 #define RDA_OSTIMER_CTRL_LOAD		BIT(30)
30 
31 #define RDA_TIMER_IRQ_MASK_OSTIMER	BIT(0)
32 
33 #define RDA_TIMER_IRQ_CLR_OSTIMER	BIT(0)
34 
35 static int rda_ostimer_start(void __iomem *base, bool periodic, u64 cycles)
36 {
37 	u32 ctrl, load_l;
38 
39 	load_l = (u32)cycles;
40 	ctrl = ((cycles >> 32) & 0xffffff);
41 	ctrl |= RDA_OSTIMER_CTRL_LOAD | RDA_OSTIMER_CTRL_ENABLE;
42 	if (periodic)
43 		ctrl |= RDA_OSTIMER_CTRL_REPEAT;
44 
45 	/* Enable ostimer interrupt first */
46 	writel_relaxed(RDA_TIMER_IRQ_MASK_OSTIMER,
47 		       base + RDA_TIMER_IRQ_MASK_SET);
48 
49 	/* Write low 32 bits first, high 24 bits are with ctrl */
50 	writel_relaxed(load_l, base + RDA_OSTIMER_LOADVAL_L);
51 	writel_relaxed(ctrl, base + RDA_OSTIMER_CTRL);
52 
53 	return 0;
54 }
55 
56 static int rda_ostimer_stop(void __iomem *base)
57 {
58 	/* Disable ostimer interrupt first */
59 	writel_relaxed(RDA_TIMER_IRQ_MASK_OSTIMER,
60 		       base + RDA_TIMER_IRQ_MASK_CLR);
61 
62 	writel_relaxed(0, base + RDA_OSTIMER_CTRL);
63 
64 	return 0;
65 }
66 
67 static int rda_ostimer_set_state_shutdown(struct clock_event_device *evt)
68 {
69 	struct timer_of *to = to_timer_of(evt);
70 
71 	rda_ostimer_stop(timer_of_base(to));
72 
73 	return 0;
74 }
75 
76 static int rda_ostimer_set_state_oneshot(struct clock_event_device *evt)
77 {
78 	struct timer_of *to = to_timer_of(evt);
79 
80 	rda_ostimer_stop(timer_of_base(to));
81 
82 	return 0;
83 }
84 
85 static int rda_ostimer_set_state_periodic(struct clock_event_device *evt)
86 {
87 	struct timer_of *to = to_timer_of(evt);
88 	unsigned long cycles_per_jiffy;
89 
90 	rda_ostimer_stop(timer_of_base(to));
91 
92 	cycles_per_jiffy = ((unsigned long long)NSEC_PER_SEC / HZ *
93 			     evt->mult) >> evt->shift;
94 	rda_ostimer_start(timer_of_base(to), true, cycles_per_jiffy);
95 
96 	return 0;
97 }
98 
99 static int rda_ostimer_tick_resume(struct clock_event_device *evt)
100 {
101 	return 0;
102 }
103 
104 static int rda_ostimer_set_next_event(unsigned long evt,
105 				      struct clock_event_device *ev)
106 {
107 	struct timer_of *to = to_timer_of(ev);
108 
109 	rda_ostimer_start(timer_of_base(to), false, evt);
110 
111 	return 0;
112 }
113 
114 static irqreturn_t rda_ostimer_interrupt(int irq, void *dev_id)
115 {
116 	struct clock_event_device *evt = dev_id;
117 	struct timer_of *to = to_timer_of(evt);
118 
119 	/* clear timer int */
120 	writel_relaxed(RDA_TIMER_IRQ_CLR_OSTIMER,
121 		       timer_of_base(to) + RDA_TIMER_IRQ_CLR);
122 
123 	if (evt->event_handler)
124 		evt->event_handler(evt);
125 
126 	return IRQ_HANDLED;
127 }
128 
129 static struct timer_of rda_ostimer_of = {
130 	.flags = TIMER_OF_IRQ | TIMER_OF_BASE,
131 
132 	.clkevt = {
133 		.name = "rda-ostimer",
134 		.rating = 250,
135 		.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
136 			    CLOCK_EVT_FEAT_DYNIRQ,
137 		.set_state_shutdown = rda_ostimer_set_state_shutdown,
138 		.set_state_oneshot = rda_ostimer_set_state_oneshot,
139 		.set_state_periodic = rda_ostimer_set_state_periodic,
140 		.tick_resume = rda_ostimer_tick_resume,
141 		.set_next_event	= rda_ostimer_set_next_event,
142 	},
143 
144 	.of_base = {
145 		.name = "rda-timer",
146 		.index = 0,
147 	},
148 
149 	.of_irq = {
150 		.name = "ostimer",
151 		.handler = rda_ostimer_interrupt,
152 		.flags = IRQF_TIMER,
153 	},
154 };
155 
156 static u64 rda_hwtimer_read(struct clocksource *cs)
157 {
158 	void __iomem *base = timer_of_base(&rda_ostimer_of);
159 	u32 lo, hi;
160 
161 	/* Always read low 32 bits first */
162 	do {
163 		lo = readl_relaxed(base + RDA_HWTIMER_LOCKVAL_L);
164 		hi = readl_relaxed(base + RDA_HWTIMER_LOCKVAL_H);
165 	} while (hi != readl_relaxed(base + RDA_HWTIMER_LOCKVAL_H));
166 
167 	return ((u64)hi << 32) | lo;
168 }
169 
170 static struct clocksource rda_hwtimer_clocksource = {
171 	.name           = "rda-timer",
172 	.rating         = 400,
173 	.read           = rda_hwtimer_read,
174 	.mask           = CLOCKSOURCE_MASK(64),
175 	.flags          = CLOCK_SOURCE_IS_CONTINUOUS,
176 };
177 
178 static int __init rda_timer_init(struct device_node *np)
179 {
180 	unsigned long rate = 2000000;
181 	int ret;
182 
183 	ret = timer_of_init(np, &rda_ostimer_of);
184 	if (ret)
185 		return ret;
186 
187 	clocksource_register_hz(&rda_hwtimer_clocksource, rate);
188 
189 	clockevents_config_and_register(&rda_ostimer_of.clkevt, rate,
190 					0x2, UINT_MAX);
191 
192 	return 0;
193 }
194 
195 TIMER_OF_DECLARE(rda8810pl, "rda,8810pl-timer", rda_timer_init);
196