1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
/*
* linux/drivers/clocksource/zevio-timer.c
*
* Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2, as
* published by the Free Software Foundation.
*
*/
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/cpumask.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#define IO_CURRENT_VAL 0x00
#define IO_DIVIDER 0x04
#define IO_CONTROL 0x08
#define IO_TIMER1 0x00
#define IO_TIMER2 0x0C
#define IO_MATCH_BEGIN 0x18
#define IO_MATCH(x) (IO_MATCH_BEGIN + ((x) << 2))
#define IO_INTR_STS 0x00
#define IO_INTR_ACK 0x00
#define IO_INTR_MSK 0x04
#define CNTL_STOP_TIMER (1 << 4)
#define CNTL_RUN_TIMER (0 << 4)
#define CNTL_INC (1 << 3)
#define CNTL_DEC (0 << 3)
#define CNTL_TOZERO 0
#define CNTL_MATCH(x) ((x) + 1)
#define CNTL_FOREVER 7
/* There are 6 match registers but we only use one. */
#define TIMER_MATCH 0
#define TIMER_INTR_MSK (1 << (TIMER_MATCH))
#define TIMER_INTR_ALL 0x3F
struct zevio_timer {
void __iomem *base;
void __iomem *timer1, *timer2;
void __iomem *interrupt_regs;
struct clk *clk;
struct clock_event_device clkevt;
struct irqaction clkevt_irq;
char clocksource_name[64];
char clockevent_name[64];
};
static int zevio_timer_set_event(unsigned long delta,
struct clock_event_device *dev)
{
struct zevio_timer *timer = container_of(dev, struct zevio_timer,
clkevt);
writel(delta, timer->timer1 + IO_CURRENT_VAL);
writel(CNTL_RUN_TIMER | CNTL_DEC | CNTL_MATCH(TIMER_MATCH),
timer->timer1 + IO_CONTROL);
return 0;
}
static int zevio_timer_shutdown(struct clock_event_device *dev)
{
struct zevio_timer *timer = container_of(dev, struct zevio_timer,
clkevt);
/* Disable timer interrupts */
writel(0, timer->interrupt_regs + IO_INTR_MSK);
writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK);
/* Stop timer */
writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL);
return 0;
}
static int zevio_timer_set_oneshot(struct clock_event_device *dev)
{
struct zevio_timer *timer = container_of(dev, struct zevio_timer,
clkevt);
/* Enable timer interrupts */
writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_MSK);
writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK);
return 0;
}
static irqreturn_t zevio_timer_interrupt(int irq, void *dev_id)
{
struct zevio_timer *timer = dev_id;
u32 intr;
intr = readl(timer->interrupt_regs + IO_INTR_ACK);
if (!(intr & TIMER_INTR_MSK))
return IRQ_NONE;
writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_ACK);
writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL);
if (timer->clkevt.event_handler)
timer->clkevt.event_handler(&timer->clkevt);
return IRQ_HANDLED;
}
static int __init zevio_timer_add(struct device_node *node)
{
struct zevio_timer *timer;
struct resource res;
int irqnr, ret;
timer = kzalloc(sizeof(*timer), GFP_KERNEL);
if (!timer)
return -ENOMEM;
timer->base = of_iomap(node, 0);
if (!timer->base) {
ret = -EINVAL;
goto error_free;
}
timer->timer1 = timer->base + IO_TIMER1;
timer->timer2 = timer->base + IO_TIMER2;
timer->clk = of_clk_get(node, 0);
if (IS_ERR(timer->clk)) {
ret = PTR_ERR(timer->clk);
pr_err("Timer clock not found! (error %d)\n", ret);
goto error_unmap;
}
timer->interrupt_regs = of_iomap(node, 1);
irqnr = irq_of_parse_and_map(node, 0);
of_address_to_resource(node, 0, &res);
scnprintf(timer->clocksource_name, sizeof(timer->clocksource_name),
"%llx.%s_clocksource",
(unsigned long long)res.start, node->name);
scnprintf(timer->clockevent_name, sizeof(timer->clockevent_name),
"%llx.%s_clockevent",
(unsigned long long)res.start, node->name);
if (timer->interrupt_regs && irqnr) {
timer->clkevt.name = timer->clockevent_name;
timer->clkevt.set_next_event = zevio_timer_set_event;
timer->clkevt.set_state_shutdown = zevio_timer_shutdown;
timer->clkevt.set_state_oneshot = zevio_timer_set_oneshot;
timer->clkevt.tick_resume = zevio_timer_set_oneshot;
timer->clkevt.rating = 200;
timer->clkevt.cpumask = cpu_all_mask;
timer->clkevt.features = CLOCK_EVT_FEAT_ONESHOT;
timer->clkevt.irq = irqnr;
writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL);
writel(0, timer->timer1 + IO_DIVIDER);
/* Start with timer interrupts disabled */
writel(0, timer->interrupt_regs + IO_INTR_MSK);
writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK);
/* Interrupt to occur when timer value matches 0 */
writel(0, timer->base + IO_MATCH(TIMER_MATCH));
timer->clkevt_irq.name = timer->clockevent_name;
timer->clkevt_irq.handler = zevio_timer_interrupt;
timer->clkevt_irq.dev_id = timer;
timer->clkevt_irq.flags = IRQF_TIMER | IRQF_IRQPOLL;
setup_irq(irqnr, &timer->clkevt_irq);
clockevents_config_and_register(&timer->clkevt,
clk_get_rate(timer->clk), 0x0001, 0xffff);
pr_info("Added %s as clockevent\n", timer->clockevent_name);
}
writel(CNTL_STOP_TIMER, timer->timer2 + IO_CONTROL);
writel(0, timer->timer2 + IO_CURRENT_VAL);
writel(0, timer->timer2 + IO_DIVIDER);
writel(CNTL_RUN_TIMER | CNTL_FOREVER | CNTL_INC,
timer->timer2 + IO_CONTROL);
clocksource_mmio_init(timer->timer2 + IO_CURRENT_VAL,
timer->clocksource_name,
clk_get_rate(timer->clk),
200, 16,
clocksource_mmio_readw_up);
pr_info("Added %s as clocksource\n", timer->clocksource_name);
return 0;
error_unmap:
iounmap(timer->base);
error_free:
kfree(timer);
return ret;
}
static void __init zevio_timer_init(struct device_node *node)
{
BUG_ON(zevio_timer_add(node));
}
CLOCKSOURCE_OF_DECLARE(zevio_timer, "lsi,zevio-timer", zevio_timer_init);
|
