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/sched_clock.h>
30#include <asm/hardware/arm_timer.h>
31
32static long __init sp804_get_clock_rate(const char *name)
33{
34 struct clk *clk;
35 long rate;
36 int err;
37
38 clk = clk_get_sys("sp804", name);
39 if (IS_ERR(clk)) {
40 pr_err("sp804: %s clock not found: %d\n", name,
41 (int)PTR_ERR(clk));
42 return PTR_ERR(clk);
43 }
44
45 err = clk_prepare(clk);
46 if (err) {
47 pr_err("sp804: %s clock failed to prepare: %d\n", name, err);
48 clk_put(clk);
49 return err;
50 }
51
52 err = clk_enable(clk);
53 if (err) {
54 pr_err("sp804: %s clock failed to enable: %d\n", name, err);
55 clk_unprepare(clk);
56 clk_put(clk);
57 return err;
58 }
59
60 rate = clk_get_rate(clk);
61 if (rate < 0) {
62 pr_err("sp804: %s clock failed to get rate: %ld\n", name, rate);
63 clk_disable(clk);
64 clk_unprepare(clk);
65 clk_put(clk);
66 }
67
68 return rate;
69}
70
71static void __iomem *sched_clock_base;
72
73static u32 sp804_read(void)
74{
75 return ~readl_relaxed(sched_clock_base + TIMER_VALUE);
76}
77
78void __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
79 const char *name,
80 int use_sched_clock)
81{
82 long rate = sp804_get_clock_rate(name);
83
84 if (rate < 0)
85 return;
86
87 /* setup timer 0 as free-running clocksource */
88 writel(0, base + TIMER_CTRL);
89 writel(0xffffffff, base + TIMER_LOAD);
90 writel(0xffffffff, base + TIMER_VALUE);
91 writel(TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC,
92 base + TIMER_CTRL);
93
94 clocksource_mmio_init(base + TIMER_VALUE, name,
95 rate, 200, 32, clocksource_mmio_readl_down);
96
97 if (use_sched_clock) {
98 sched_clock_base = base;
99 setup_sched_clock(sp804_read, 32, rate);
100 }
101}
102
103
104static void __iomem *clkevt_base;
105static unsigned long clkevt_reload;
106
107/*
108 * IRQ handler for the timer
109 */
110static irqreturn_t sp804_timer_interrupt(int irq, void *dev_id)
111{
112 struct clock_event_device *evt = dev_id;
113
114 /* clear the interrupt */
115 writel(1, clkevt_base + TIMER_INTCLR);
116
117 evt->event_handler(evt);
118
119 return IRQ_HANDLED;
120}
121
122static void sp804_set_mode(enum clock_event_mode mode,
123 struct clock_event_device *evt)
124{
125 unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE;
126
127 writel(ctrl, clkevt_base + TIMER_CTRL);
128
129 switch (mode) {
130 case CLOCK_EVT_MODE_PERIODIC:
131 writel(clkevt_reload, clkevt_base + TIMER_LOAD);
132 ctrl |= TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
133 break;
134
135 case CLOCK_EVT_MODE_ONESHOT:
136 /* period set, and timer enabled in 'next_event' hook */
137 ctrl |= TIMER_CTRL_ONESHOT;
138 break;
139
140 case CLOCK_EVT_MODE_UNUSED:
141 case CLOCK_EVT_MODE_SHUTDOWN:
142 default:
143 break;
144 }
145
146 writel(ctrl, clkevt_base + TIMER_CTRL);
147}
148
149static int sp804_set_next_event(unsigned long next,
150 struct clock_event_device *evt)
151{
152 unsigned long ctrl = readl(clkevt_base + TIMER_CTRL);
153
154 writel(next, clkevt_base + TIMER_LOAD);
155 writel(ctrl | TIMER_CTRL_ENABLE, clkevt_base + TIMER_CTRL);
156
157 return 0;
158}
159
160static struct clock_event_device sp804_clockevent = {
161 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
162 .set_mode = sp804_set_mode,
163 .set_next_event = sp804_set_next_event,
164 .rating = 300,
165 .cpumask = cpu_all_mask,
166};
167
168static struct irqaction sp804_timer_irq = {
169 .name = "timer",
170 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
171 .handler = sp804_timer_interrupt,
172 .dev_id = &sp804_clockevent,
173};
174
175void __init sp804_clockevents_init(void __iomem *base, unsigned int irq,
176 const char *name)
177{
178 struct clock_event_device *evt = &sp804_clockevent;
179 long rate = sp804_get_clock_rate(name);
180
181 if (rate < 0)
182 return;
183
184 clkevt_base = base;
185 clkevt_reload = DIV_ROUND_CLOSEST(rate, HZ);
186 evt->name = name;
187 evt->irq = irq;
188
189 setup_irq(irq, &sp804_timer_irq);
190 clockevents_config_and_register(evt, rate, 0xf, 0xffffffff);
191}