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
37static void __iomem *timer_base;
38
39/*
40 * Free-running clocksource handling.
41 */
42static u64 notrace orion_read_sched_clock(void)
43{
44	return ~readl(timer_base + TIMER0_VAL);
45}
46
47/*
48 * Clockevent handling.
49 */
50static u32 ticks_per_jiffy;
51
52static 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
63static 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
80static 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
89static 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
95static struct irqaction orion_clkevt_irq = {
96	.name		= "orion_event",
97	.flags		= IRQF_TIMER,
98	.handler	= orion_clkevt_irq_handler,
99};
100
101static 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}
142CLOCKSOURCE_OF_DECLARE(orion_timer, "marvell,orion-timer", orion_timer_init);
143