Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * linux/arch/arm/common/timer-sp.c
3 *
4 * Copyright (C) 1999 - 2003 ARM Limited
5 * Copyright (C) 2000 Deep Blue Solutions Ltd
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21#include <linux/clk.h>
22#include <linux/clocksource.h>
23#include <linux/clockchips.h>
24#include <linux/err.h>
25#include <linux/interrupt.h>
26#include <linux/irq.h>
27#include <linux/io.h>
28
29#include <asm/hardware/arm_timer.h>
30
31static long __init sp804_get_clock_rate(const char *name)
32{
33 struct clk *clk;
34 long rate;
35 int err;
36
37 clk = clk_get_sys("sp804", name);
38 if (IS_ERR(clk)) {
39 pr_err("sp804: %s clock not found: %d\n", name,
40 (int)PTR_ERR(clk));
41 return PTR_ERR(clk);
42 }
43
44 err = clk_prepare(clk);
45 if (err) {
46 pr_err("sp804: %s clock failed to prepare: %d\n", name, err);
47 clk_put(clk);
48 return err;
49 }
50
51 err = clk_enable(clk);
52 if (err) {
53 pr_err("sp804: %s clock failed to enable: %d\n", name, err);
54 clk_unprepare(clk);
55 clk_put(clk);
56 return err;
57 }
58
59 rate = clk_get_rate(clk);
60 if (rate < 0) {
61 pr_err("sp804: %s clock failed to get rate: %ld\n", name, rate);
62 clk_disable(clk);
63 clk_unprepare(clk);
64 clk_put(clk);
65 }
66
67 return rate;
68}
69
70void __init sp804_clocksource_init(void __iomem *base, const char *name)
71{
72 long rate = sp804_get_clock_rate(name);
73
74 if (rate < 0)
75 return;
76
77 /* setup timer 0 as free-running clocksource */
78 writel(0, base + TIMER_CTRL);
79 writel(0xffffffff, base + TIMER_LOAD);
80 writel(0xffffffff, base + TIMER_VALUE);
81 writel(TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC,
82 base + TIMER_CTRL);
83
84 clocksource_mmio_init(base + TIMER_VALUE, name,
85 rate, 200, 32, clocksource_mmio_readl_down);
86}
87
88
89static void __iomem *clkevt_base;
90static unsigned long clkevt_reload;
91
92/*
93 * IRQ handler for the timer
94 */
95static irqreturn_t sp804_timer_interrupt(int irq, void *dev_id)
96{
97 struct clock_event_device *evt = dev_id;
98
99 /* clear the interrupt */
100 writel(1, clkevt_base + TIMER_INTCLR);
101
102 evt->event_handler(evt);
103
104 return IRQ_HANDLED;
105}
106
107static void sp804_set_mode(enum clock_event_mode mode,
108 struct clock_event_device *evt)
109{
110 unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE;
111
112 writel(ctrl, clkevt_base + TIMER_CTRL);
113
114 switch (mode) {
115 case CLOCK_EVT_MODE_PERIODIC:
116 writel(clkevt_reload, clkevt_base + TIMER_LOAD);
117 ctrl |= TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
118 break;
119
120 case CLOCK_EVT_MODE_ONESHOT:
121 /* period set, and timer enabled in 'next_event' hook */
122 ctrl |= TIMER_CTRL_ONESHOT;
123 break;
124
125 case CLOCK_EVT_MODE_UNUSED:
126 case CLOCK_EVT_MODE_SHUTDOWN:
127 default:
128 break;
129 }
130
131 writel(ctrl, clkevt_base + TIMER_CTRL);
132}
133
134static int sp804_set_next_event(unsigned long next,
135 struct clock_event_device *evt)
136{
137 unsigned long ctrl = readl(clkevt_base + TIMER_CTRL);
138
139 writel(next, clkevt_base + TIMER_LOAD);
140 writel(ctrl | TIMER_CTRL_ENABLE, clkevt_base + TIMER_CTRL);
141
142 return 0;
143}
144
145static struct clock_event_device sp804_clockevent = {
146 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
147 .set_mode = sp804_set_mode,
148 .set_next_event = sp804_set_next_event,
149 .rating = 300,
150 .cpumask = cpu_all_mask,
151};
152
153static struct irqaction sp804_timer_irq = {
154 .name = "timer",
155 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
156 .handler = sp804_timer_interrupt,
157 .dev_id = &sp804_clockevent,
158};
159
160void __init sp804_clockevents_init(void __iomem *base, unsigned int irq,
161 const char *name)
162{
163 struct clock_event_device *evt = &sp804_clockevent;
164 long rate = sp804_get_clock_rate(name);
165
166 if (rate < 0)
167 return;
168
169 clkevt_base = base;
170 clkevt_reload = DIV_ROUND_CLOSEST(rate, HZ);
171 evt->name = name;
172 evt->irq = irq;
173
174 setup_irq(irq, &sp804_timer_irq);
175 clockevents_config_and_register(evt, rate, 0xf, 0xffffffff);
176}