1 /*
2 * arch/arm/mach-netx/time.c
3 *
4 * Copyright (c) 2005 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2
8 * as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20 #include <linux/init.h>
21 #include <linux/interrupt.h>
22 #include <linux/irq.h>
23 #include <linux/clocksource.h>
24 #include <linux/clockchips.h>
25 #include <linux/io.h>
26
27 #include <mach/hardware.h>
28 #include <asm/mach/time.h>
29 #include <mach/netx-regs.h>
30
31 #define NETX_CLOCK_FREQ 100000000
32 #define NETX_LATCH DIV_ROUND_CLOSEST(NETX_CLOCK_FREQ, HZ)
33
34 #define TIMER_CLOCKEVENT 0
35 #define TIMER_CLOCKSOURCE 1
36
timer_shutdown(struct clock_event_device * evt)37 static inline void timer_shutdown(struct clock_event_device *evt)
38 {
39 /* disable timer */
40 writel(0, NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKEVENT));
41 }
42
netx_shutdown(struct clock_event_device * evt)43 static int netx_shutdown(struct clock_event_device *evt)
44 {
45 timer_shutdown(evt);
46
47 return 0;
48 }
49
netx_set_oneshot(struct clock_event_device * evt)50 static int netx_set_oneshot(struct clock_event_device *evt)
51 {
52 u32 tmode = NETX_GPIO_COUNTER_CTRL_IRQ_EN | NETX_GPIO_COUNTER_CTRL_RUN;
53
54 timer_shutdown(evt);
55 writel(0, NETX_GPIO_COUNTER_MAX(TIMER_CLOCKEVENT));
56 writel(tmode, NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKEVENT));
57
58 return 0;
59 }
60
netx_set_periodic(struct clock_event_device * evt)61 static int netx_set_periodic(struct clock_event_device *evt)
62 {
63 u32 tmode = NETX_GPIO_COUNTER_CTRL_RST_EN |
64 NETX_GPIO_COUNTER_CTRL_IRQ_EN | NETX_GPIO_COUNTER_CTRL_RUN;
65
66 timer_shutdown(evt);
67 writel(NETX_LATCH, NETX_GPIO_COUNTER_MAX(TIMER_CLOCKEVENT));
68 writel(tmode, NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKEVENT));
69
70 return 0;
71 }
72
netx_set_next_event(unsigned long evt,struct clock_event_device * clk)73 static int netx_set_next_event(unsigned long evt,
74 struct clock_event_device *clk)
75 {
76 writel(0 - evt, NETX_GPIO_COUNTER_CURRENT(TIMER_CLOCKEVENT));
77 return 0;
78 }
79
80 static struct clock_event_device netx_clockevent = {
81 .name = "netx-timer" __stringify(TIMER_CLOCKEVENT),
82 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
83 .set_next_event = netx_set_next_event,
84 .set_state_shutdown = netx_shutdown,
85 .set_state_periodic = netx_set_periodic,
86 .set_state_oneshot = netx_set_oneshot,
87 .tick_resume = netx_shutdown,
88 };
89
90 /*
91 * IRQ handler for the timer
92 */
93 static irqreturn_t
netx_timer_interrupt(int irq,void * dev_id)94 netx_timer_interrupt(int irq, void *dev_id)
95 {
96 struct clock_event_device *evt = &netx_clockevent;
97
98 /* acknowledge interrupt */
99 writel(COUNTER_BIT(0), NETX_GPIO_IRQ);
100
101 evt->event_handler(evt);
102
103 return IRQ_HANDLED;
104 }
105
106 static struct irqaction netx_timer_irq = {
107 .name = "NetX Timer Tick",
108 .flags = IRQF_TIMER | IRQF_IRQPOLL,
109 .handler = netx_timer_interrupt,
110 };
111
112 /*
113 * Set up timer interrupt
114 */
netx_timer_init(void)115 void __init netx_timer_init(void)
116 {
117 /* disable timer initially */
118 writel(0, NETX_GPIO_COUNTER_CTRL(0));
119
120 /* Reset the timer value to zero */
121 writel(0, NETX_GPIO_COUNTER_CURRENT(0));
122
123 writel(NETX_LATCH, NETX_GPIO_COUNTER_MAX(0));
124
125 /* acknowledge interrupt */
126 writel(COUNTER_BIT(0), NETX_GPIO_IRQ);
127
128 /* Enable the interrupt in the specific timer
129 * register and start timer
130 */
131 writel(COUNTER_BIT(0), NETX_GPIO_IRQ_ENABLE);
132 writel(NETX_GPIO_COUNTER_CTRL_IRQ_EN | NETX_GPIO_COUNTER_CTRL_RUN,
133 NETX_GPIO_COUNTER_CTRL(0));
134
135 setup_irq(NETX_IRQ_TIMER0, &netx_timer_irq);
136
137 /* Setup timer one for clocksource */
138 writel(0, NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKSOURCE));
139 writel(0, NETX_GPIO_COUNTER_CURRENT(TIMER_CLOCKSOURCE));
140 writel(0xffffffff, NETX_GPIO_COUNTER_MAX(TIMER_CLOCKSOURCE));
141
142 writel(NETX_GPIO_COUNTER_CTRL_RUN,
143 NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKSOURCE));
144
145 clocksource_mmio_init(NETX_GPIO_COUNTER_CURRENT(TIMER_CLOCKSOURCE),
146 "netx_timer", NETX_CLOCK_FREQ, 200, 32, clocksource_mmio_readl_up);
147
148 /* with max_delta_ns >= delta2ns(0x800) the system currently runs fine.
149 * Adding some safety ... */
150 netx_clockevent.cpumask = cpumask_of(0);
151 clockevents_config_and_register(&netx_clockevent, NETX_CLOCK_FREQ,
152 0xa00, 0xfffffffe);
153 }
154
