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_enable(clk);
45 if (err) {
46 pr_err("sp804: %s clock failed to enable: %d\n", name, err);
47 clk_put(clk);
48 return err;
49 }
50
51 rate = clk_get_rate(clk);
52 if (rate < 0) {
53 pr_err("sp804: %s clock failed to get rate: %ld\n", name, rate);
54 clk_disable(clk);
55 clk_put(clk);
56 }
57
58 return rate;
59}
60
61void __init sp804_clocksource_init(void __iomem *base, const char *name)
62{
63 long rate = sp804_get_clock_rate(name);
64
65 if (rate < 0)
66 return;
67
68 /* setup timer 0 as free-running clocksource */
69 writel(0, base + TIMER_CTRL);
70 writel(0xffffffff, base + TIMER_LOAD);
71 writel(0xffffffff, base + TIMER_VALUE);
72 writel(TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC,
73 base + TIMER_CTRL);
74
75 clocksource_mmio_init(base + TIMER_VALUE, name,
76 rate, 200, 32, clocksource_mmio_readl_down);
77}
78
79
80static void __iomem *clkevt_base;
81static unsigned long clkevt_reload;
82
83/*
84 * IRQ handler for the timer
85 */
86static irqreturn_t sp804_timer_interrupt(int irq, void *dev_id)
87{
88 struct clock_event_device *evt = dev_id;
89
90 /* clear the interrupt */
91 writel(1, clkevt_base + TIMER_INTCLR);
92
93 evt->event_handler(evt);
94
95 return IRQ_HANDLED;
96}
97
98static void sp804_set_mode(enum clock_event_mode mode,
99 struct clock_event_device *evt)
100{
101 unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE;
102
103 writel(ctrl, clkevt_base + TIMER_CTRL);
104
105 switch (mode) {
106 case CLOCK_EVT_MODE_PERIODIC:
107 writel(clkevt_reload, clkevt_base + TIMER_LOAD);
108 ctrl |= TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
109 break;
110
111 case CLOCK_EVT_MODE_ONESHOT:
112 /* period set, and timer enabled in 'next_event' hook */
113 ctrl |= TIMER_CTRL_ONESHOT;
114 break;
115
116 case CLOCK_EVT_MODE_UNUSED:
117 case CLOCK_EVT_MODE_SHUTDOWN:
118 default:
119 break;
120 }
121
122 writel(ctrl, clkevt_base + TIMER_CTRL);
123}
124
125static int sp804_set_next_event(unsigned long next,
126 struct clock_event_device *evt)
127{
128 unsigned long ctrl = readl(clkevt_base + TIMER_CTRL);
129
130 writel(next, clkevt_base + TIMER_LOAD);
131 writel(ctrl | TIMER_CTRL_ENABLE, clkevt_base + TIMER_CTRL);
132
133 return 0;
134}
135
136static struct clock_event_device sp804_clockevent = {
137 .shift = 32,
138 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
139 .set_mode = sp804_set_mode,
140 .set_next_event = sp804_set_next_event,
141 .rating = 300,
142 .cpumask = cpu_all_mask,
143};
144
145static struct irqaction sp804_timer_irq = {
146 .name = "timer",
147 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
148 .handler = sp804_timer_interrupt,
149 .dev_id = &sp804_clockevent,
150};
151
152void __init sp804_clockevents_init(void __iomem *base, unsigned int irq,
153 const char *name)
154{
155 struct clock_event_device *evt = &sp804_clockevent;
156 long rate = sp804_get_clock_rate(name);
157
158 if (rate < 0)
159 return;
160
161 clkevt_base = base;
162 clkevt_reload = DIV_ROUND_CLOSEST(rate, HZ);
163
164 evt->name = name;
165 evt->irq = irq;
166 evt->mult = div_sc(rate, NSEC_PER_SEC, evt->shift);
167 evt->max_delta_ns = clockevent_delta2ns(0xffffffff, evt);
168 evt->min_delta_ns = clockevent_delta2ns(0xf, evt);
169
170 setup_irq(irq, &sp804_timer_irq);
171 clockevents_register_device(evt);
172}