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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/drivers/clocksource/zevio-timer.c
4 *
5 * Copyright (C) 2013 Daniel Tang <[email protected]>
6 */
7
8#include <linux/io.h>
9#include <linux/irq.h>
10#include <linux/of.h>
11#include <linux/of_address.h>
12#include <linux/of_irq.h>
13#include <linux/clk.h>
14#include <linux/clockchips.h>
15#include <linux/cpumask.h>
16#include <linux/interrupt.h>
17#include <linux/slab.h>
18
19#define IO_CURRENT_VAL 0x00
20#define IO_DIVIDER 0x04
21#define IO_CONTROL 0x08
22
23#define IO_TIMER1 0x00
24#define IO_TIMER2 0x0C
25
26#define IO_MATCH_BEGIN 0x18
27#define IO_MATCH(x) (IO_MATCH_BEGIN + ((x) << 2))
28
29#define IO_INTR_STS 0x00
30#define IO_INTR_ACK 0x00
31#define IO_INTR_MSK 0x04
32
33#define CNTL_STOP_TIMER (1 << 4)
34#define CNTL_RUN_TIMER (0 << 4)
35
36#define CNTL_INC (1 << 3)
37#define CNTL_DEC (0 << 3)
38
39#define CNTL_TOZERO 0
40#define CNTL_MATCH(x) ((x) + 1)
41#define CNTL_FOREVER 7
42
43/* There are 6 match registers but we only use one. */
44#define TIMER_MATCH 0
45
46#define TIMER_INTR_MSK (1 << (TIMER_MATCH))
47#define TIMER_INTR_ALL 0x3F
48
49struct zevio_timer {
50 void __iomem *base;
51 void __iomem *timer1, *timer2;
52 void __iomem *interrupt_regs;
53
54 struct clk *clk;
55 struct clock_event_device clkevt;
56
57 char clocksource_name[64];
58 char clockevent_name[64];
59};
60
61static int zevio_timer_set_event(unsigned long delta,
62 struct clock_event_device *dev)
63{
64 struct zevio_timer *timer = container_of(dev, struct zevio_timer,
65 clkevt);
66
67 writel(delta, timer->timer1 + IO_CURRENT_VAL);
68 writel(CNTL_RUN_TIMER | CNTL_DEC | CNTL_MATCH(TIMER_MATCH),
69 timer->timer1 + IO_CONTROL);
70
71 return 0;
72}
73
74static int zevio_timer_shutdown(struct clock_event_device *dev)
75{
76 struct zevio_timer *timer = container_of(dev, struct zevio_timer,
77 clkevt);
78
79 /* Disable timer interrupts */
80 writel(0, timer->interrupt_regs + IO_INTR_MSK);
81 writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK);
82 /* Stop timer */
83 writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL);
84 return 0;
85}
86
87static int zevio_timer_set_oneshot(struct clock_event_device *dev)
88{
89 struct zevio_timer *timer = container_of(dev, struct zevio_timer,
90 clkevt);
91
92 /* Enable timer interrupts */
93 writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_MSK);
94 writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK);
95 return 0;
96}
97
98static irqreturn_t zevio_timer_interrupt(int irq, void *dev_id)
99{
100 struct zevio_timer *timer = dev_id;
101 u32 intr;
102
103 intr = readl(timer->interrupt_regs + IO_INTR_ACK);
104 if (!(intr & TIMER_INTR_MSK))
105 return IRQ_NONE;
106
107 writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_ACK);
108 writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL);
109
110 if (timer->clkevt.event_handler)
111 timer->clkevt.event_handler(&timer->clkevt);
112
113 return IRQ_HANDLED;
114}
115
116static int __init zevio_timer_add(struct device_node *node)
117{
118 struct zevio_timer *timer;
119 struct resource res;
120 int irqnr, ret;
121
122 timer = kzalloc_obj(*timer);
123 if (!timer)
124 return -ENOMEM;
125
126 timer->base = of_iomap(node, 0);
127 if (!timer->base) {
128 ret = -EINVAL;
129 goto error_free;
130 }
131 timer->timer1 = timer->base + IO_TIMER1;
132 timer->timer2 = timer->base + IO_TIMER2;
133
134 timer->clk = of_clk_get(node, 0);
135 if (IS_ERR(timer->clk)) {
136 ret = PTR_ERR(timer->clk);
137 pr_err("Timer clock not found! (error %d)\n", ret);
138 goto error_unmap;
139 }
140
141 timer->interrupt_regs = of_iomap(node, 1);
142 irqnr = irq_of_parse_and_map(node, 0);
143
144 of_address_to_resource(node, 0, &res);
145 scnprintf(timer->clocksource_name, sizeof(timer->clocksource_name),
146 "%llx.%pOFn_clocksource",
147 (unsigned long long)res.start, node);
148
149 scnprintf(timer->clockevent_name, sizeof(timer->clockevent_name),
150 "%llx.%pOFn_clockevent",
151 (unsigned long long)res.start, node);
152
153 if (timer->interrupt_regs && irqnr) {
154 timer->clkevt.name = timer->clockevent_name;
155 timer->clkevt.set_next_event = zevio_timer_set_event;
156 timer->clkevt.set_state_shutdown = zevio_timer_shutdown;
157 timer->clkevt.set_state_oneshot = zevio_timer_set_oneshot;
158 timer->clkevt.tick_resume = zevio_timer_set_oneshot;
159 timer->clkevt.rating = 200;
160 timer->clkevt.cpumask = cpu_possible_mask;
161 timer->clkevt.features = CLOCK_EVT_FEAT_ONESHOT;
162 timer->clkevt.irq = irqnr;
163
164 writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL);
165 writel(0, timer->timer1 + IO_DIVIDER);
166
167 /* Start with timer interrupts disabled */
168 writel(0, timer->interrupt_regs + IO_INTR_MSK);
169 writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK);
170
171 /* Interrupt to occur when timer value matches 0 */
172 writel(0, timer->base + IO_MATCH(TIMER_MATCH));
173
174 if (request_irq(irqnr, zevio_timer_interrupt,
175 IRQF_TIMER | IRQF_IRQPOLL,
176 timer->clockevent_name, timer)) {
177 pr_err("%s: request_irq() failed\n",
178 timer->clockevent_name);
179 }
180
181 clockevents_config_and_register(&timer->clkevt,
182 clk_get_rate(timer->clk), 0x0001, 0xffff);
183 pr_info("Added %s as clockevent\n", timer->clockevent_name);
184 }
185
186 writel(CNTL_STOP_TIMER, timer->timer2 + IO_CONTROL);
187 writel(0, timer->timer2 + IO_CURRENT_VAL);
188 writel(0, timer->timer2 + IO_DIVIDER);
189 writel(CNTL_RUN_TIMER | CNTL_FOREVER | CNTL_INC,
190 timer->timer2 + IO_CONTROL);
191
192 clocksource_mmio_init(timer->timer2 + IO_CURRENT_VAL,
193 timer->clocksource_name,
194 clk_get_rate(timer->clk),
195 200, 16,
196 clocksource_mmio_readw_up);
197
198 pr_info("Added %s as clocksource\n", timer->clocksource_name);
199
200 return 0;
201error_unmap:
202 iounmap(timer->base);
203error_free:
204 kfree(timer);
205 return ret;
206}
207
208static int __init zevio_timer_init(struct device_node *node)
209{
210 return zevio_timer_add(node);
211}
212
213TIMER_OF_DECLARE(zevio_timer, "lsi,zevio-timer", zevio_timer_init);