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
npcm7xx_timer_resume(struct clock_event_device * evt)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
npcm7xx_timer_shutdown(struct clock_event_device * evt)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
npcm7xx_timer_oneshot(struct clock_event_device * evt)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
npcm7xx_timer_periodic(struct clock_event_device * evt)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
npcm7xx_clockevent_set_next_event(unsigned long evt,struct clock_event_device * clk)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
npcm7xx_timer0_interrupt(int irq,void * dev_id)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
npcm7xx_clockevents_init(void)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
npcm7xx_clocksource_init(void)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
npcm7xx_timer_init(struct device_node * np)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