1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2014-2018 Nuvoton Technologies tomer.maimon@nuvoton.com
4  * All rights reserved.
5  *
6  * Copyright 2017 Google, Inc.
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/sched.h>
11 #include <linux/init.h>
12 #include <linux/interrupt.h>
13 #include <linux/err.h>
14 #include <linux/clk.h>
15 #include <linux/io.h>
16 #include <linux/clockchips.h>
17 #include <linux/of_irq.h>
18 #include <linux/of_address.h>
19 #include "timer-of.h"
20 
21 /* Timers registers */
22 #define NPCM7XX_REG_TCSR0	0x0 /* Timer 0 Control and Status Register */
23 #define NPCM7XX_REG_TICR0	0x8 /* Timer 0 Initial Count Register */
24 #define NPCM7XX_REG_TCSR1	0x4 /* Timer 1 Control and Status Register */
25 #define NPCM7XX_REG_TICR1	0xc /* Timer 1 Initial Count Register */
26 #define NPCM7XX_REG_TDR1	0x14 /* Timer 1 Data Register */
27 #define NPCM7XX_REG_TISR	0x18 /* Timer Interrupt Status Register */
28 
29 /* Timers control */
30 #define NPCM7XX_Tx_RESETINT		0x1f
31 #define NPCM7XX_Tx_PERIOD		BIT(27)
32 #define NPCM7XX_Tx_INTEN		BIT(29)
33 #define NPCM7XX_Tx_COUNTEN		BIT(30)
34 #define NPCM7XX_Tx_ONESHOT		0x0
35 #define NPCM7XX_Tx_OPER			GENMASK(28, 27)
36 #define NPCM7XX_Tx_MIN_PRESCALE		0x1
37 #define NPCM7XX_Tx_TDR_MASK_BITS	24
38 #define NPCM7XX_Tx_MAX_CNT		0xFFFFFF
39 #define NPCM7XX_T0_CLR_INT		0x1
40 #define NPCM7XX_Tx_CLR_CSR		0x0
41 
42 /* Timers operating mode */
43 #define NPCM7XX_START_PERIODIC_Tx (NPCM7XX_Tx_PERIOD | NPCM7XX_Tx_COUNTEN | \
44 					NPCM7XX_Tx_INTEN | \
45 					NPCM7XX_Tx_MIN_PRESCALE)
46 
47 #define NPCM7XX_START_ONESHOT_Tx (NPCM7XX_Tx_ONESHOT | NPCM7XX_Tx_COUNTEN | \
48 					NPCM7XX_Tx_INTEN | \
49 					NPCM7XX_Tx_MIN_PRESCALE)
50 
51 #define NPCM7XX_START_Tx (NPCM7XX_Tx_COUNTEN | NPCM7XX_Tx_PERIOD | \
52 				NPCM7XX_Tx_MIN_PRESCALE)
53 
54 #define NPCM7XX_DEFAULT_CSR (NPCM7XX_Tx_CLR_CSR | NPCM7XX_Tx_MIN_PRESCALE)
55 
56 static int npcm7xx_timer_resume(struct clock_event_device *evt)
57 {
58 	struct timer_of *to = to_timer_of(evt);
59 	u32 val;
60 
61 	val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
62 	val |= NPCM7XX_Tx_COUNTEN;
63 	writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
64 
65 	return 0;
66 }
67 
68 static int npcm7xx_timer_shutdown(struct clock_event_device *evt)
69 {
70 	struct timer_of *to = to_timer_of(evt);
71 	u32 val;
72 
73 	val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
74 	val &= ~NPCM7XX_Tx_COUNTEN;
75 	writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
76 
77 	return 0;
78 }
79 
80 static int npcm7xx_timer_oneshot(struct clock_event_device *evt)
81 {
82 	struct timer_of *to = to_timer_of(evt);
83 	u32 val;
84 
85 	val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
86 	val &= ~NPCM7XX_Tx_OPER;
87 	val |= NPCM7XX_START_ONESHOT_Tx;
88 	writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
89 
90 	return 0;
91 }
92 
93 static int npcm7xx_timer_periodic(struct clock_event_device *evt)
94 {
95 	struct timer_of *to = to_timer_of(evt);
96 	u32 val;
97 
98 	writel(timer_of_period(to), timer_of_base(to) + NPCM7XX_REG_TICR0);
99 
100 	val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
101 	val &= ~NPCM7XX_Tx_OPER;
102 	val |= NPCM7XX_START_PERIODIC_Tx;
103 	writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
104 
105 	return 0;
106 }
107 
108 static int npcm7xx_clockevent_set_next_event(unsigned long evt,
109 		struct clock_event_device *clk)
110 {
111 	struct timer_of *to = to_timer_of(clk);
112 	u32 val;
113 
114 	writel(evt, timer_of_base(to) + NPCM7XX_REG_TICR0);
115 	val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
116 	val |= NPCM7XX_START_Tx;
117 	writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
118 
119 	return 0;
120 }
121 
122 static irqreturn_t npcm7xx_timer0_interrupt(int irq, void *dev_id)
123 {
124 	struct clock_event_device *evt = (struct clock_event_device *)dev_id;
125 	struct timer_of *to = to_timer_of(evt);
126 
127 	writel(NPCM7XX_T0_CLR_INT, timer_of_base(to) + NPCM7XX_REG_TISR);
128 
129 	evt->event_handler(evt);
130 
131 	return IRQ_HANDLED;
132 }
133 
134 static struct timer_of npcm7xx_to = {
135 	.flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,
136 
137 	.clkevt = {
138 		.name		    = "npcm7xx-timer0",
139 		.features	    = CLOCK_EVT_FEAT_PERIODIC |
140 				      CLOCK_EVT_FEAT_ONESHOT,
141 		.set_next_event	    = npcm7xx_clockevent_set_next_event,
142 		.set_state_shutdown = npcm7xx_timer_shutdown,
143 		.set_state_periodic = npcm7xx_timer_periodic,
144 		.set_state_oneshot  = npcm7xx_timer_oneshot,
145 		.tick_resume	    = npcm7xx_timer_resume,
146 		.rating		    = 300,
147 	},
148 
149 	.of_irq = {
150 		.handler = npcm7xx_timer0_interrupt,
151 		.flags = IRQF_TIMER | IRQF_IRQPOLL,
152 	},
153 };
154 
155 static void __init npcm7xx_clockevents_init(void)
156 {
157 	writel(NPCM7XX_DEFAULT_CSR,
158 		timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TCSR0);
159 
160 	writel(NPCM7XX_Tx_RESETINT,
161 		timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TISR);
162 
163 	npcm7xx_to.clkevt.cpumask = cpumask_of(0);
164 	clockevents_config_and_register(&npcm7xx_to.clkevt,
165 					timer_of_rate(&npcm7xx_to),
166 					0x1, NPCM7XX_Tx_MAX_CNT);
167 }
168 
169 static void __init npcm7xx_clocksource_init(void)
170 {
171 	u32 val;
172 
173 	writel(NPCM7XX_DEFAULT_CSR,
174 		timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TCSR1);
175 	writel(NPCM7XX_Tx_MAX_CNT,
176 		timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TICR1);
177 
178 	val = readl(timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TCSR1);
179 	val |= NPCM7XX_START_Tx;
180 	writel(val, timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TCSR1);
181 
182 	clocksource_mmio_init(timer_of_base(&npcm7xx_to) +
183 				NPCM7XX_REG_TDR1,
184 				"npcm7xx-timer1", timer_of_rate(&npcm7xx_to),
185 				200, (unsigned int)NPCM7XX_Tx_TDR_MASK_BITS,
186 				clocksource_mmio_readl_down);
187 }
188 
189 static int __init npcm7xx_timer_init(struct device_node *np)
190 {
191 	int ret;
192 
193 	ret = timer_of_init(np, &npcm7xx_to);
194 	if (ret)
195 		return ret;
196 
197 	/* Clock input is divided by PRESCALE + 1 before it is fed */
198 	/* to the counter */
199 	npcm7xx_to.of_clk.rate = npcm7xx_to.of_clk.rate /
200 		(NPCM7XX_Tx_MIN_PRESCALE + 1);
201 
202 	npcm7xx_clocksource_init();
203 	npcm7xx_clockevents_init();
204 
205 	pr_info("Enabling NPCM7xx clocksource timer base: %px, IRQ: %d ",
206 		timer_of_base(&npcm7xx_to), timer_of_irq(&npcm7xx_to));
207 
208 	return 0;
209 }
210 
211 TIMER_OF_DECLARE(npcm7xx, "nuvoton,npcm750-timer", npcm7xx_timer_init);
212 
213