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
|
/*
* Integrator/AP timer driver
* Copyright (C) 2000-2003 Deep Blue Solutions Ltd
* Copyright (c) 2014, Linaro Limited
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/clk.h>
#include <linux/clocksource.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/sched_clock.h>
#include "timer-sp.h"
static void __iomem * sched_clk_base;
static u64 notrace integrator_read_sched_clock(void)
{
return -readl(sched_clk_base + TIMER_VALUE);
}
static void integrator_clocksource_init(unsigned long inrate,
void __iomem *base)
{
u32 ctrl = TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC;
unsigned long rate = inrate;
if (rate >= 1500000) {
rate /= 16;
ctrl |= TIMER_CTRL_DIV16;
}
writel(0xffff, base + TIMER_LOAD);
writel(ctrl, base + TIMER_CTRL);
clocksource_mmio_init(base + TIMER_VALUE, "timer2",
rate, 200, 16, clocksource_mmio_readl_down);
sched_clk_base = base;
sched_clock_register(integrator_read_sched_clock, 16, rate);
}
static unsigned long timer_reload;
static void __iomem * clkevt_base;
/*
* IRQ handler for the timer
*/
static irqreturn_t integrator_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
/* clear the interrupt */
writel(1, clkevt_base + TIMER_INTCLR);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static void clkevt_set_mode(enum clock_event_mode mode, struct clock_event_device *evt)
{
u32 ctrl = readl(clkevt_base + TIMER_CTRL) & ~TIMER_CTRL_ENABLE;
/* Disable timer */
writel(ctrl, clkevt_base + TIMER_CTRL);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
/* Enable the timer and start the periodic tick */
writel(timer_reload, clkevt_base + TIMER_LOAD);
ctrl |= TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
writel(ctrl, clkevt_base + TIMER_CTRL);
break;
case CLOCK_EVT_MODE_ONESHOT:
/* Leave the timer disabled, .set_next_event will enable it */
ctrl &= ~TIMER_CTRL_PERIODIC;
writel(ctrl, clkevt_base + TIMER_CTRL);
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_RESUME:
default:
/* Just leave in disabled state */
break;
}
}
static int clkevt_set_next_event(unsigned long next, struct clock_event_device *evt)
{
unsigned long ctrl = readl(clkevt_base + TIMER_CTRL);
writel(ctrl & ~TIMER_CTRL_ENABLE, clkevt_base + TIMER_CTRL);
writel(next, clkevt_base + TIMER_LOAD);
writel(ctrl | TIMER_CTRL_ENABLE, clkevt_base + TIMER_CTRL);
return 0;
}
static struct clock_event_device integrator_clockevent = {
.name = "timer1",
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.set_mode = clkevt_set_mode,
.set_next_event = clkevt_set_next_event,
.rating = 300,
};
static struct irqaction integrator_timer_irq = {
.name = "timer",
.flags = IRQF_TIMER | IRQF_IRQPOLL,
.handler = integrator_timer_interrupt,
.dev_id = &integrator_clockevent,
};
static void integrator_clockevent_init(unsigned long inrate,
void __iomem *base, int irq)
{
unsigned long rate = inrate;
unsigned int ctrl = 0;
clkevt_base = base;
/* Calculate and program a divisor */
if (rate > 0x100000 * HZ) {
rate /= 256;
ctrl |= TIMER_CTRL_DIV256;
} else if (rate > 0x10000 * HZ) {
rate /= 16;
ctrl |= TIMER_CTRL_DIV16;
}
timer_reload = rate / HZ;
writel(ctrl, clkevt_base + TIMER_CTRL);
setup_irq(irq, &integrator_timer_irq);
clockevents_config_and_register(&integrator_clockevent,
rate,
1,
0xffffU);
}
static void __init integrator_ap_timer_init_of(struct device_node *node)
{
const char *path;
void __iomem *base;
int err;
int irq;
struct clk *clk;
unsigned long rate;
struct device_node *pri_node;
struct device_node *sec_node;
base = of_io_request_and_map(node, 0, "integrator-timer");
if (!base)
return;
clk = of_clk_get(node, 0);
if (IS_ERR(clk)) {
pr_err("No clock for %s\n", node->name);
return;
}
clk_prepare_enable(clk);
rate = clk_get_rate(clk);
writel(0, base + TIMER_CTRL);
err = of_property_read_string(of_aliases,
"arm,timer-primary", &path);
if (WARN_ON(err))
return;
pri_node = of_find_node_by_path(path);
err = of_property_read_string(of_aliases,
"arm,timer-secondary", &path);
if (WARN_ON(err))
return;
sec_node = of_find_node_by_path(path);
if (node == pri_node) {
/* The primary timer lacks IRQ, use as clocksource */
integrator_clocksource_init(rate, base);
return;
}
if (node == sec_node) {
/* The secondary timer will drive the clock event */
irq = irq_of_parse_and_map(node, 0);
integrator_clockevent_init(rate, base, irq);
return;
}
pr_info("Timer @%p unused\n", base);
clk_disable_unprepare(clk);
}
CLOCKSOURCE_OF_DECLARE(integrator_ap_timer, "arm,integrator-timer",
integrator_ap_timer_init_of);
|
