1 /*
2 * Marvell Orion SoC timer handling.
3 *
4 * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
5 *
6 * This file is licensed under the terms of the GNU General Public
7 * License version 2. This program is licensed "as is" without any
8 * warranty of any kind, whether express or implied.
9 *
10 * Timer 0 is used as free-running clocksource, while timer 1 is
11 * used as clock_event_device.
12 */
13
14 #include <linux/kernel.h>
15 #include <linux/bitops.h>
16 #include <linux/clk.h>
17 #include <linux/clockchips.h>
18 #include <linux/interrupt.h>
19 #include <linux/of_address.h>
20 #include <linux/of_irq.h>
21 #include <linux/spinlock.h>
22 #include <linux/sched_clock.h>
23
24 #define TIMER_CTRL 0x00
25 #define TIMER0_EN BIT(0)
26 #define TIMER0_RELOAD_EN BIT(1)
27 #define TIMER1_EN BIT(2)
28 #define TIMER1_RELOAD_EN BIT(3)
29 #define TIMER0_RELOAD 0x10
30 #define TIMER0_VAL 0x14
31 #define TIMER1_RELOAD 0x18
32 #define TIMER1_VAL 0x1c
33
34 #define ORION_ONESHOT_MIN 1
35 #define ORION_ONESHOT_MAX 0xfffffffe
36
37 static void __iomem *timer_base;
38
39 /*
40 * Free-running clocksource handling.
41 */
orion_read_sched_clock(void)42 static u64 notrace orion_read_sched_clock(void)
43 {
44 return ~readl(timer_base + TIMER0_VAL);
45 }
46
47 /*
48 * Clockevent handling.
49 */
50 static u32 ticks_per_jiffy;
51
orion_clkevt_next_event(unsigned long delta,struct clock_event_device * dev)52 static int orion_clkevt_next_event(unsigned long delta,
53 struct clock_event_device *dev)
54 {
55 /* setup and enable one-shot timer */
56 writel(delta, timer_base + TIMER1_VAL);
57 atomic_io_modify(timer_base + TIMER_CTRL,
58 TIMER1_RELOAD_EN | TIMER1_EN, TIMER1_EN);
59
60 return 0;
61 }
62
orion_clkevt_mode(enum clock_event_mode mode,struct clock_event_device * dev)63 static void orion_clkevt_mode(enum clock_event_mode mode,
64 struct clock_event_device *dev)
65 {
66 if (mode == CLOCK_EVT_MODE_PERIODIC) {
67 /* setup and enable periodic timer at 1/HZ intervals */
68 writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD);
69 writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL);
70 atomic_io_modify(timer_base + TIMER_CTRL,
71 TIMER1_RELOAD_EN | TIMER1_EN,
72 TIMER1_RELOAD_EN | TIMER1_EN);
73 } else {
74 /* disable timer */
75 atomic_io_modify(timer_base + TIMER_CTRL,
76 TIMER1_RELOAD_EN | TIMER1_EN, 0);
77 }
78 }
79
80 static struct clock_event_device orion_clkevt = {
81 .name = "orion_event",
82 .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
83 .shift = 32,
84 .rating = 300,
85 .set_next_event = orion_clkevt_next_event,
86 .set_mode = orion_clkevt_mode,
87 };
88
orion_clkevt_irq_handler(int irq,void * dev_id)89 static irqreturn_t orion_clkevt_irq_handler(int irq, void *dev_id)
90 {
91 orion_clkevt.event_handler(&orion_clkevt);
92 return IRQ_HANDLED;
93 }
94
95 static struct irqaction orion_clkevt_irq = {
96 .name = "orion_event",
97 .flags = IRQF_TIMER,
98 .handler = orion_clkevt_irq_handler,
99 };
100
orion_timer_init(struct device_node * np)101 static void __init orion_timer_init(struct device_node *np)
102 {
103 struct clk *clk;
104 int irq;
105
106 /* timer registers are shared with watchdog timer */
107 timer_base = of_iomap(np, 0);
108 if (!timer_base)
109 panic("%s: unable to map resource\n", np->name);
110
111 clk = of_clk_get(np, 0);
112 if (IS_ERR(clk))
113 panic("%s: unable to get clk\n", np->name);
114 clk_prepare_enable(clk);
115
116 /* we are only interested in timer1 irq */
117 irq = irq_of_parse_and_map(np, 1);
118 if (irq <= 0)
119 panic("%s: unable to parse timer1 irq\n", np->name);
120
121 /* setup timer0 as free-running clocksource */
122 writel(~0, timer_base + TIMER0_VAL);
123 writel(~0, timer_base + TIMER0_RELOAD);
124 atomic_io_modify(timer_base + TIMER_CTRL,
125 TIMER0_RELOAD_EN | TIMER0_EN,
126 TIMER0_RELOAD_EN | TIMER0_EN);
127 clocksource_mmio_init(timer_base + TIMER0_VAL, "orion_clocksource",
128 clk_get_rate(clk), 300, 32,
129 clocksource_mmio_readl_down);
130 sched_clock_register(orion_read_sched_clock, 32, clk_get_rate(clk));
131
132 /* setup timer1 as clockevent timer */
133 if (setup_irq(irq, &orion_clkevt_irq))
134 panic("%s: unable to setup irq\n", np->name);
135
136 ticks_per_jiffy = (clk_get_rate(clk) + HZ/2) / HZ;
137 orion_clkevt.cpumask = cpumask_of(0);
138 orion_clkevt.irq = irq;
139 clockevents_config_and_register(&orion_clkevt, clk_get_rate(clk),
140 ORION_ONESHOT_MIN, ORION_ONESHOT_MAX);
141 }
142 CLOCKSOURCE_OF_DECLARE(orion_timer, "marvell,orion-timer", orion_timer_init);
143