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10#include <linux/errno.h>
11#include <linux/kernel.h>
12#include <linux/interrupt.h>
13#include <linux/init.h>
14#include <linux/clockchips.h>
15#include <linux/clk.h>
16#include <linux/io.h>
17#include <linux/of.h>
18#include <linux/of_address.h>
19#include <linux/of_irq.h>
20
21#define _8TCR 0
22#define _8TCSR 2
23#define TCORA 4
24#define TCORB 6
25#define _8TCNT 8
26
27#define CMIEA 6
28#define CMFA 6
29
30#define FLAG_STARTED (1 << 3)
31
32#define SCALE 64
33
34#define bset(b, a) iowrite8(ioread8(a) | (1 << (b)), (a))
35#define bclr(b, a) iowrite8(ioread8(a) & ~(1 << (b)), (a))
36
37struct timer8_priv {
38 struct clock_event_device ced;
39 void __iomem *mapbase;
40 unsigned long flags;
41 unsigned int rate;
42};
43
44static irqreturn_t timer8_interrupt(int irq, void *dev_id)
45{
46 struct timer8_priv *p = dev_id;
47
48 if (clockevent_state_oneshot(&p->ced))
49 iowrite16be(0x0000, p->mapbase + _8TCR);
50
51 p->ced.event_handler(&p->ced);
52
53 bclr(CMFA, p->mapbase + _8TCSR);
54
55 return IRQ_HANDLED;
56}
57
58static void timer8_set_next(struct timer8_priv *p, unsigned long delta)
59{
60 if (delta >= 0x10000)
61 pr_warn("delta out of range\n");
62 bclr(CMIEA, p->mapbase + _8TCR);
63 iowrite16be(delta, p->mapbase + TCORA);
64 iowrite16be(0x0000, p->mapbase + _8TCNT);
65 bclr(CMFA, p->mapbase + _8TCSR);
66 bset(CMIEA, p->mapbase + _8TCR);
67}
68
69static int timer8_enable(struct timer8_priv *p)
70{
71 iowrite16be(0xffff, p->mapbase + TCORA);
72 iowrite16be(0x0000, p->mapbase + _8TCNT);
73 iowrite16be(0x0c02, p->mapbase + _8TCR);
74
75 return 0;
76}
77
78static int timer8_start(struct timer8_priv *p)
79{
80 int ret;
81
82 if ((p->flags & FLAG_STARTED))
83 return 0;
84
85 ret = timer8_enable(p);
86 if (!ret)
87 p->flags |= FLAG_STARTED;
88
89 return ret;
90}
91
92static void timer8_stop(struct timer8_priv *p)
93{
94 iowrite16be(0x0000, p->mapbase + _8TCR);
95}
96
97static inline struct timer8_priv *ced_to_priv(struct clock_event_device *ced)
98{
99 return container_of(ced, struct timer8_priv, ced);
100}
101
102static void timer8_clock_event_start(struct timer8_priv *p, unsigned long delta)
103{
104 timer8_start(p);
105 timer8_set_next(p, delta);
106}
107
108static int timer8_clock_event_shutdown(struct clock_event_device *ced)
109{
110 timer8_stop(ced_to_priv(ced));
111 return 0;
112}
113
114static int timer8_clock_event_periodic(struct clock_event_device *ced)
115{
116 struct timer8_priv *p = ced_to_priv(ced);
117
118 pr_info("%s: used for periodic clock events\n", ced->name);
119 timer8_stop(p);
120 timer8_clock_event_start(p, (p->rate + HZ/2) / HZ);
121
122 return 0;
123}
124
125static int timer8_clock_event_oneshot(struct clock_event_device *ced)
126{
127 struct timer8_priv *p = ced_to_priv(ced);
128
129 pr_info("%s: used for oneshot clock events\n", ced->name);
130 timer8_stop(p);
131 timer8_clock_event_start(p, 0x10000);
132
133 return 0;
134}
135
136static int timer8_clock_event_next(unsigned long delta,
137 struct clock_event_device *ced)
138{
139 struct timer8_priv *p = ced_to_priv(ced);
140
141 BUG_ON(!clockevent_state_oneshot(ced));
142 timer8_set_next(p, delta - 1);
143
144 return 0;
145}
146
147static struct timer8_priv timer8_priv = {
148 .ced = {
149 .name = "h8300_8timer",
150 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
151 .rating = 200,
152 .set_next_event = timer8_clock_event_next,
153 .set_state_shutdown = timer8_clock_event_shutdown,
154 .set_state_periodic = timer8_clock_event_periodic,
155 .set_state_oneshot = timer8_clock_event_oneshot,
156 },
157};
158
159static int __init h8300_8timer_init(struct device_node *node)
160{
161 void __iomem *base;
162 int irq, ret;
163 struct clk *clk;
164
165 clk = of_clk_get(node, 0);
166 if (IS_ERR(clk)) {
167 pr_err("failed to get clock for clockevent\n");
168 return PTR_ERR(clk);
169 }
170
171 ret = ENXIO;
172 base = of_iomap(node, 0);
173 if (!base) {
174 pr_err("failed to map registers for clockevent\n");
175 goto free_clk;
176 }
177
178 ret = -EINVAL;
179 irq = irq_of_parse_and_map(node, 0);
180 if (!irq) {
181 pr_err("failed to get irq for clockevent\n");
182 goto unmap_reg;
183 }
184
185 timer8_priv.mapbase = base;
186
187 timer8_priv.rate = clk_get_rate(clk) / SCALE;
188 if (!timer8_priv.rate) {
189 pr_err("Failed to get rate for the clocksource\n");
190 goto unmap_reg;
191 }
192
193 if (request_irq(irq, timer8_interrupt, IRQF_TIMER,
194 timer8_priv.ced.name, &timer8_priv) < 0) {
195 pr_err("failed to request irq %d for clockevent\n", irq);
196 goto unmap_reg;
197 }
198
199 clockevents_config_and_register(&timer8_priv.ced,
200 timer8_priv.rate, 1, 0x0000ffff);
201
202 return 0;
203unmap_reg:
204 iounmap(base);
205free_clk:
206 clk_put(clk);
207 return ret;
208}
209
210CLOCKSOURCE_OF_DECLARE(h8300_8bit, "renesas,8bit-timer", h8300_8timer_init);
211
