1/*
2 * Allwinner SoCs hstimer driver.
3 *
4 * Copyright (C) 2013 Maxime Ripard
5 *
6 * Maxime Ripard <maxime.ripard@free-electrons.com>
7 *
8 * This file is licensed under the terms of the GNU General Public
9 * License version 2. This program is licensed "as is" without any
10 * warranty of any kind, whether express or implied.
11 */
12
13#include <linux/clk.h>
14#include <linux/clockchips.h>
15#include <linux/clocksource.h>
16#include <linux/delay.h>
17#include <linux/interrupt.h>
18#include <linux/irq.h>
19#include <linux/irqreturn.h>
20#include <linux/reset.h>
21#include <linux/slab.h>
22#include <linux/of.h>
23#include <linux/of_address.h>
24#include <linux/of_irq.h>
25
26#define TIMER_IRQ_EN_REG 0x00
27#define TIMER_IRQ_EN(val) BIT(val)
28#define TIMER_IRQ_ST_REG 0x04
29#define TIMER_CTL_REG(val) (0x20 * (val) + 0x10)
30#define TIMER_CTL_ENABLE BIT(0)
31#define TIMER_CTL_RELOAD BIT(1)
32#define TIMER_CTL_CLK_PRES(val) (((val) & 0x7) << 4)
33#define TIMER_CTL_ONESHOT BIT(7)
34#define TIMER_INTVAL_LO_REG(val) (0x20 * (val) + 0x14)
35#define TIMER_INTVAL_HI_REG(val) (0x20 * (val) + 0x18)
36#define TIMER_CNTVAL_LO_REG(val) (0x20 * (val) + 0x1c)
37#define TIMER_CNTVAL_HI_REG(val) (0x20 * (val) + 0x20)
38
39#define TIMER_SYNC_TICKS 3
40
41struct sun5i_timer {
42 void __iomem *base;
43 struct clk *clk;
44 struct notifier_block clk_rate_cb;
45 u32 ticks_per_jiffy;
46};
47
48#define to_sun5i_timer(x) \
49 container_of(x, struct sun5i_timer, clk_rate_cb)
50
51struct sun5i_timer_clksrc {
52 struct sun5i_timer timer;
53 struct clocksource clksrc;
54};
55
56#define to_sun5i_timer_clksrc(x) \
57 container_of(x, struct sun5i_timer_clksrc, clksrc)
58
59struct sun5i_timer_clkevt {
60 struct sun5i_timer timer;
61 struct clock_event_device clkevt;
62};
63
64#define to_sun5i_timer_clkevt(x) \
65 container_of(x, struct sun5i_timer_clkevt, clkevt)
66
67/*
68 * When we disable a timer, we need to wait at least for 2 cycles of
69 * the timer source clock. We will use for that the clocksource timer
70 * that is already setup and runs at the same frequency than the other
71 * timers, and we never will be disabled.
72 */
73static void sun5i_clkevt_sync(struct sun5i_timer_clkevt *ce)
74{
75 u32 old = readl(ce->timer.base + TIMER_CNTVAL_LO_REG(1));
76
77 while ((old - readl(ce->timer.base + TIMER_CNTVAL_LO_REG(1))) < TIMER_SYNC_TICKS)
78 cpu_relax();
79}
80
81static void sun5i_clkevt_time_stop(struct sun5i_timer_clkevt *ce, u8 timer)
82{
83 u32 val = readl(ce->timer.base + TIMER_CTL_REG(timer));
84 writel(val & ~TIMER_CTL_ENABLE, ce->timer.base + TIMER_CTL_REG(timer));
85
86 sun5i_clkevt_sync(ce);
87}
88
89static void sun5i_clkevt_time_setup(struct sun5i_timer_clkevt *ce, u8 timer, u32 delay)
90{
91 writel(delay, ce->timer.base + TIMER_INTVAL_LO_REG(timer));
92}
93
94static void sun5i_clkevt_time_start(struct sun5i_timer_clkevt *ce, u8 timer, bool periodic)
95{
96 u32 val = readl(ce->timer.base + TIMER_CTL_REG(timer));
97
98 if (periodic)
99 val &= ~TIMER_CTL_ONESHOT;
100 else
101 val |= TIMER_CTL_ONESHOT;
102
103 writel(val | TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
104 ce->timer.base + TIMER_CTL_REG(timer));
105}
106
107static int sun5i_clkevt_shutdown(struct clock_event_device *clkevt)
108{
109 struct sun5i_timer_clkevt *ce = to_sun5i_timer_clkevt(clkevt);
110
111 sun5i_clkevt_time_stop(ce, 0);
112 return 0;
113}
114
115static int sun5i_clkevt_set_oneshot(struct clock_event_device *clkevt)
116{
117 struct sun5i_timer_clkevt *ce = to_sun5i_timer_clkevt(clkevt);
118
119 sun5i_clkevt_time_stop(ce, 0);
120 sun5i_clkevt_time_start(ce, 0, false);
121 return 0;
122}
123
124static int sun5i_clkevt_set_periodic(struct clock_event_device *clkevt)
125{
126 struct sun5i_timer_clkevt *ce = to_sun5i_timer_clkevt(clkevt);
127
128 sun5i_clkevt_time_stop(ce, 0);
129 sun5i_clkevt_time_setup(ce, 0, ce->timer.ticks_per_jiffy);
130 sun5i_clkevt_time_start(ce, 0, true);
131 return 0;
132}
133
134static int sun5i_clkevt_next_event(unsigned long evt,
135 struct clock_event_device *clkevt)
136{
137 struct sun5i_timer_clkevt *ce = to_sun5i_timer_clkevt(clkevt);
138
139 sun5i_clkevt_time_stop(ce, 0);
140 sun5i_clkevt_time_setup(ce, 0, evt - TIMER_SYNC_TICKS);
141 sun5i_clkevt_time_start(ce, 0, false);
142
143 return 0;
144}
145
146static irqreturn_t sun5i_timer_interrupt(int irq, void *dev_id)
147{
148 struct sun5i_timer_clkevt *ce = (struct sun5i_timer_clkevt *)dev_id;
149
150 writel(0x1, ce->timer.base + TIMER_IRQ_ST_REG);
151 ce->clkevt.event_handler(&ce->clkevt);
152
153 return IRQ_HANDLED;
154}
155
156static u64 sun5i_clksrc_read(struct clocksource *clksrc)
157{
158 struct sun5i_timer_clksrc *cs = to_sun5i_timer_clksrc(clksrc);
159
160 return ~readl(cs->timer.base + TIMER_CNTVAL_LO_REG(1));
161}
162
163static int sun5i_rate_cb_clksrc(struct notifier_block *nb,
164 unsigned long event, void *data)
165{
166 struct clk_notifier_data *ndata = data;
167 struct sun5i_timer *timer = to_sun5i_timer(nb);
168 struct sun5i_timer_clksrc *cs = container_of(timer, struct sun5i_timer_clksrc, timer);
169
170 switch (event) {
171 case PRE_RATE_CHANGE:
172 clocksource_unregister(&cs->clksrc);
173 break;
174
175 case POST_RATE_CHANGE:
176 clocksource_register_hz(&cs->clksrc, ndata->new_rate);
177 break;
178
179 default:
180 break;
181 }
182
183 return NOTIFY_DONE;
184}
185
186static int __init sun5i_setup_clocksource(struct device_node *node,
187 void __iomem *base,
188 struct clk *clk, int irq)
189{
190 struct sun5i_timer_clksrc *cs;
191 unsigned long rate;
192 int ret;
193
194 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
195 if (!cs)
196 return -ENOMEM;
197
198 ret = clk_prepare_enable(clk);
199 if (ret) {
200 pr_err("Couldn't enable parent clock\n");
201 goto err_free;
202 }
203
204 rate = clk_get_rate(clk);
205 if (!rate) {
206 pr_err("Couldn't get parent clock rate\n");
207 ret = -EINVAL;
208 goto err_disable_clk;
209 }
210
211 cs->timer.base = base;
212 cs->timer.clk = clk;
213 cs->timer.clk_rate_cb.notifier_call = sun5i_rate_cb_clksrc;
214 cs->timer.clk_rate_cb.next = NULL;
215
216 ret = clk_notifier_register(clk, &cs->timer.clk_rate_cb);
217 if (ret) {
218 pr_err("Unable to register clock notifier.\n");
219 goto err_disable_clk;
220 }
221
222 writel(~0, base + TIMER_INTVAL_LO_REG(1));
223 writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
224 base + TIMER_CTL_REG(1));
225
226 cs->clksrc.name = node->name;
227 cs->clksrc.rating = 340;
228 cs->clksrc.read = sun5i_clksrc_read;
229 cs->clksrc.mask = CLOCKSOURCE_MASK(32);
230 cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
231
232 ret = clocksource_register_hz(&cs->clksrc, rate);
233 if (ret) {
234 pr_err("Couldn't register clock source.\n");
235 goto err_remove_notifier;
236 }
237
238 return 0;
239
240err_remove_notifier:
241 clk_notifier_unregister(clk, &cs->timer.clk_rate_cb);
242err_disable_clk:
243 clk_disable_unprepare(clk);
244err_free:
245 kfree(cs);
246 return ret;
247}
248
249static int sun5i_rate_cb_clkevt(struct notifier_block *nb,
250 unsigned long event, void *data)
251{
252 struct clk_notifier_data *ndata = data;
253 struct sun5i_timer *timer = to_sun5i_timer(nb);
254 struct sun5i_timer_clkevt *ce = container_of(timer, struct sun5i_timer_clkevt, timer);
255
256 if (event == POST_RATE_CHANGE) {
257 clockevents_update_freq(&ce->clkevt, ndata->new_rate);
258 ce->timer.ticks_per_jiffy = DIV_ROUND_UP(ndata->new_rate, HZ);
259 }
260
261 return NOTIFY_DONE;
262}
263
264static int __init sun5i_setup_clockevent(struct device_node *node, void __iomem *base,
265 struct clk *clk, int irq)
266{
267 struct sun5i_timer_clkevt *ce;
268 unsigned long rate;
269 int ret;
270 u32 val;
271
272 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
273 if (!ce)
274 return -ENOMEM;
275
276 ret = clk_prepare_enable(clk);
277 if (ret) {
278 pr_err("Couldn't enable parent clock\n");
279 goto err_free;
280 }
281
282 rate = clk_get_rate(clk);
283 if (!rate) {
284 pr_err("Couldn't get parent clock rate\n");
285 ret = -EINVAL;
286 goto err_disable_clk;
287 }
288
289 ce->timer.base = base;
290 ce->timer.ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
291 ce->timer.clk = clk;
292 ce->timer.clk_rate_cb.notifier_call = sun5i_rate_cb_clkevt;
293 ce->timer.clk_rate_cb.next = NULL;
294
295 ret = clk_notifier_register(clk, &ce->timer.clk_rate_cb);
296 if (ret) {
297 pr_err("Unable to register clock notifier.\n");
298 goto err_disable_clk;
299 }
300
301 ce->clkevt.name = node->name;
302 ce->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
303 ce->clkevt.set_next_event = sun5i_clkevt_next_event;
304 ce->clkevt.set_state_shutdown = sun5i_clkevt_shutdown;
305 ce->clkevt.set_state_periodic = sun5i_clkevt_set_periodic;
306 ce->clkevt.set_state_oneshot = sun5i_clkevt_set_oneshot;
307 ce->clkevt.tick_resume = sun5i_clkevt_shutdown;
308 ce->clkevt.rating = 340;
309 ce->clkevt.irq = irq;
310 ce->clkevt.cpumask = cpu_possible_mask;
311
312 /* Enable timer0 interrupt */
313 val = readl(base + TIMER_IRQ_EN_REG);
314 writel(val | TIMER_IRQ_EN(0), base + TIMER_IRQ_EN_REG);
315
316 clockevents_config_and_register(&ce->clkevt, rate,
317 TIMER_SYNC_TICKS, 0xffffffff);
318
319 ret = request_irq(irq, sun5i_timer_interrupt, IRQF_TIMER | IRQF_IRQPOLL,
320 "sun5i_timer0", ce);
321 if (ret) {
322 pr_err("Unable to register interrupt\n");
323 goto err_remove_notifier;
324 }
325
326 return 0;
327
328err_remove_notifier:
329 clk_notifier_unregister(clk, &ce->timer.clk_rate_cb);
330err_disable_clk:
331 clk_disable_unprepare(clk);
332err_free:
333 kfree(ce);
334 return ret;
335}
336
337static int __init sun5i_timer_init(struct device_node *node)
338{
339 struct reset_control *rstc;
340 void __iomem *timer_base;
341 struct clk *clk;
342 int irq, ret;
343
344 timer_base = of_io_request_and_map(node, 0, of_node_full_name(node));
345 if (IS_ERR(timer_base)) {
346 pr_err("Can't map registers\n");
347 return PTR_ERR(timer_base);
348 }
349
350 irq = irq_of_parse_and_map(node, 0);
351 if (irq <= 0) {
352 pr_err("Can't parse IRQ\n");
353 return -EINVAL;
354 }
355
356 clk = of_clk_get(node, 0);
357 if (IS_ERR(clk)) {
358 pr_err("Can't get timer clock\n");
359 return PTR_ERR(clk);
360 }
361
362 rstc = of_reset_control_get(node, NULL);
363 if (!IS_ERR(rstc))
364 reset_control_deassert(rstc);
365
366 ret = sun5i_setup_clocksource(node, timer_base, clk, irq);
367 if (ret)
368 return ret;
369
370 return sun5i_setup_clockevent(node, timer_base, clk, irq);
371}
372TIMER_OF_DECLARE(sun5i_a13, "allwinner,sun5i-a13-hstimer",
373 sun5i_timer_init);
374TIMER_OF_DECLARE(sun7i_a20, "allwinner,sun7i-a20-hstimer",
375 sun5i_timer_init);
376