1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Allwinner SoCs hstimer driver.
4  *
5  * Copyright (C) 2013 Maxime Ripard
6  *
7  * Maxime Ripard <maxime.ripard@free-electrons.com>
8  */
9 
10 #include <linux/clk.h>
11 #include <linux/clockchips.h>
12 #include <linux/clocksource.h>
13 #include <linux/delay.h>
14 #include <linux/interrupt.h>
15 #include <linux/irq.h>
16 #include <linux/irqreturn.h>
17 #include <linux/reset.h>
18 #include <linux/slab.h>
19 #include <linux/of.h>
20 #include <linux/of_address.h>
21 #include <linux/of_irq.h>
22 
23 #define TIMER_IRQ_EN_REG		0x00
24 #define TIMER_IRQ_EN(val)			BIT(val)
25 #define TIMER_IRQ_ST_REG		0x04
26 #define TIMER_CTL_REG(val)		(0x20 * (val) + 0x10)
27 #define TIMER_CTL_ENABLE			BIT(0)
28 #define TIMER_CTL_RELOAD			BIT(1)
29 #define TIMER_CTL_CLK_PRES(val)			(((val) & 0x7) << 4)
30 #define TIMER_CTL_ONESHOT			BIT(7)
31 #define TIMER_INTVAL_LO_REG(val)	(0x20 * (val) + 0x14)
32 #define TIMER_INTVAL_HI_REG(val)	(0x20 * (val) + 0x18)
33 #define TIMER_CNTVAL_LO_REG(val)	(0x20 * (val) + 0x1c)
34 #define TIMER_CNTVAL_HI_REG(val)	(0x20 * (val) + 0x20)
35 
36 #define TIMER_SYNC_TICKS	3
37 
38 struct sun5i_timer {
39 	void __iomem		*base;
40 	struct clk		*clk;
41 	struct notifier_block	clk_rate_cb;
42 	u32			ticks_per_jiffy;
43 };
44 
45 #define to_sun5i_timer(x) \
46 	container_of(x, struct sun5i_timer, clk_rate_cb)
47 
48 struct sun5i_timer_clksrc {
49 	struct sun5i_timer	timer;
50 	struct clocksource	clksrc;
51 };
52 
53 #define to_sun5i_timer_clksrc(x) \
54 	container_of(x, struct sun5i_timer_clksrc, clksrc)
55 
56 struct sun5i_timer_clkevt {
57 	struct sun5i_timer		timer;
58 	struct clock_event_device	clkevt;
59 };
60 
61 #define to_sun5i_timer_clkevt(x) \
62 	container_of(x, struct sun5i_timer_clkevt, clkevt)
63 
64 /*
65  * When we disable a timer, we need to wait at least for 2 cycles of
66  * the timer source clock. We will use for that the clocksource timer
67  * that is already setup and runs at the same frequency than the other
68  * timers, and we never will be disabled.
69  */
70 static void sun5i_clkevt_sync(struct sun5i_timer_clkevt *ce)
71 {
72 	u32 old = readl(ce->timer.base + TIMER_CNTVAL_LO_REG(1));
73 
74 	while ((old - readl(ce->timer.base + TIMER_CNTVAL_LO_REG(1))) < TIMER_SYNC_TICKS)
75 		cpu_relax();
76 }
77 
78 static void sun5i_clkevt_time_stop(struct sun5i_timer_clkevt *ce, u8 timer)
79 {
80 	u32 val = readl(ce->timer.base + TIMER_CTL_REG(timer));
81 	writel(val & ~TIMER_CTL_ENABLE, ce->timer.base + TIMER_CTL_REG(timer));
82 
83 	sun5i_clkevt_sync(ce);
84 }
85 
86 static void sun5i_clkevt_time_setup(struct sun5i_timer_clkevt *ce, u8 timer, u32 delay)
87 {
88 	writel(delay, ce->timer.base + TIMER_INTVAL_LO_REG(timer));
89 }
90 
91 static void sun5i_clkevt_time_start(struct sun5i_timer_clkevt *ce, u8 timer, bool periodic)
92 {
93 	u32 val = readl(ce->timer.base + TIMER_CTL_REG(timer));
94 
95 	if (periodic)
96 		val &= ~TIMER_CTL_ONESHOT;
97 	else
98 		val |= TIMER_CTL_ONESHOT;
99 
100 	writel(val | TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
101 	       ce->timer.base + TIMER_CTL_REG(timer));
102 }
103 
104 static int sun5i_clkevt_shutdown(struct clock_event_device *clkevt)
105 {
106 	struct sun5i_timer_clkevt *ce = to_sun5i_timer_clkevt(clkevt);
107 
108 	sun5i_clkevt_time_stop(ce, 0);
109 	return 0;
110 }
111 
112 static int sun5i_clkevt_set_oneshot(struct clock_event_device *clkevt)
113 {
114 	struct sun5i_timer_clkevt *ce = to_sun5i_timer_clkevt(clkevt);
115 
116 	sun5i_clkevt_time_stop(ce, 0);
117 	sun5i_clkevt_time_start(ce, 0, false);
118 	return 0;
119 }
120 
121 static int sun5i_clkevt_set_periodic(struct clock_event_device *clkevt)
122 {
123 	struct sun5i_timer_clkevt *ce = to_sun5i_timer_clkevt(clkevt);
124 
125 	sun5i_clkevt_time_stop(ce, 0);
126 	sun5i_clkevt_time_setup(ce, 0, ce->timer.ticks_per_jiffy);
127 	sun5i_clkevt_time_start(ce, 0, true);
128 	return 0;
129 }
130 
131 static int sun5i_clkevt_next_event(unsigned long evt,
132 				   struct clock_event_device *clkevt)
133 {
134 	struct sun5i_timer_clkevt *ce = to_sun5i_timer_clkevt(clkevt);
135 
136 	sun5i_clkevt_time_stop(ce, 0);
137 	sun5i_clkevt_time_setup(ce, 0, evt - TIMER_SYNC_TICKS);
138 	sun5i_clkevt_time_start(ce, 0, false);
139 
140 	return 0;
141 }
142 
143 static irqreturn_t sun5i_timer_interrupt(int irq, void *dev_id)
144 {
145 	struct sun5i_timer_clkevt *ce = dev_id;
146 
147 	writel(0x1, ce->timer.base + TIMER_IRQ_ST_REG);
148 	ce->clkevt.event_handler(&ce->clkevt);
149 
150 	return IRQ_HANDLED;
151 }
152 
153 static u64 sun5i_clksrc_read(struct clocksource *clksrc)
154 {
155 	struct sun5i_timer_clksrc *cs = to_sun5i_timer_clksrc(clksrc);
156 
157 	return ~readl(cs->timer.base + TIMER_CNTVAL_LO_REG(1));
158 }
159 
160 static int sun5i_rate_cb_clksrc(struct notifier_block *nb,
161 				unsigned long event, void *data)
162 {
163 	struct clk_notifier_data *ndata = data;
164 	struct sun5i_timer *timer = to_sun5i_timer(nb);
165 	struct sun5i_timer_clksrc *cs = container_of(timer, struct sun5i_timer_clksrc, timer);
166 
167 	switch (event) {
168 	case PRE_RATE_CHANGE:
169 		clocksource_unregister(&cs->clksrc);
170 		break;
171 
172 	case POST_RATE_CHANGE:
173 		clocksource_register_hz(&cs->clksrc, ndata->new_rate);
174 		break;
175 
176 	default:
177 		break;
178 	}
179 
180 	return NOTIFY_DONE;
181 }
182 
183 static int __init sun5i_setup_clocksource(struct device_node *node,
184 					  void __iomem *base,
185 					  struct clk *clk, int irq)
186 {
187 	struct sun5i_timer_clksrc *cs;
188 	unsigned long rate;
189 	int ret;
190 
191 	cs = kzalloc(sizeof(*cs), GFP_KERNEL);
192 	if (!cs)
193 		return -ENOMEM;
194 
195 	ret = clk_prepare_enable(clk);
196 	if (ret) {
197 		pr_err("Couldn't enable parent clock\n");
198 		goto err_free;
199 	}
200 
201 	rate = clk_get_rate(clk);
202 	if (!rate) {
203 		pr_err("Couldn't get parent clock rate\n");
204 		ret = -EINVAL;
205 		goto err_disable_clk;
206 	}
207 
208 	cs->timer.base = base;
209 	cs->timer.clk = clk;
210 	cs->timer.clk_rate_cb.notifier_call = sun5i_rate_cb_clksrc;
211 	cs->timer.clk_rate_cb.next = NULL;
212 
213 	ret = clk_notifier_register(clk, &cs->timer.clk_rate_cb);
214 	if (ret) {
215 		pr_err("Unable to register clock notifier.\n");
216 		goto err_disable_clk;
217 	}
218 
219 	writel(~0, base + TIMER_INTVAL_LO_REG(1));
220 	writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
221 	       base + TIMER_CTL_REG(1));
222 
223 	cs->clksrc.name = node->name;
224 	cs->clksrc.rating = 340;
225 	cs->clksrc.read = sun5i_clksrc_read;
226 	cs->clksrc.mask = CLOCKSOURCE_MASK(32);
227 	cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
228 
229 	ret = clocksource_register_hz(&cs->clksrc, rate);
230 	if (ret) {
231 		pr_err("Couldn't register clock source.\n");
232 		goto err_remove_notifier;
233 	}
234 
235 	return 0;
236 
237 err_remove_notifier:
238 	clk_notifier_unregister(clk, &cs->timer.clk_rate_cb);
239 err_disable_clk:
240 	clk_disable_unprepare(clk);
241 err_free:
242 	kfree(cs);
243 	return ret;
244 }
245 
246 static int sun5i_rate_cb_clkevt(struct notifier_block *nb,
247 				unsigned long event, void *data)
248 {
249 	struct clk_notifier_data *ndata = data;
250 	struct sun5i_timer *timer = to_sun5i_timer(nb);
251 	struct sun5i_timer_clkevt *ce = container_of(timer, struct sun5i_timer_clkevt, timer);
252 
253 	if (event == POST_RATE_CHANGE) {
254 		clockevents_update_freq(&ce->clkevt, ndata->new_rate);
255 		ce->timer.ticks_per_jiffy = DIV_ROUND_UP(ndata->new_rate, HZ);
256 	}
257 
258 	return NOTIFY_DONE;
259 }
260 
261 static int __init sun5i_setup_clockevent(struct device_node *node, void __iomem *base,
262 					 struct clk *clk, int irq)
263 {
264 	struct sun5i_timer_clkevt *ce;
265 	unsigned long rate;
266 	int ret;
267 	u32 val;
268 
269 	ce = kzalloc(sizeof(*ce), GFP_KERNEL);
270 	if (!ce)
271 		return -ENOMEM;
272 
273 	ret = clk_prepare_enable(clk);
274 	if (ret) {
275 		pr_err("Couldn't enable parent clock\n");
276 		goto err_free;
277 	}
278 
279 	rate = clk_get_rate(clk);
280 	if (!rate) {
281 		pr_err("Couldn't get parent clock rate\n");
282 		ret = -EINVAL;
283 		goto err_disable_clk;
284 	}
285 
286 	ce->timer.base = base;
287 	ce->timer.ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
288 	ce->timer.clk = clk;
289 	ce->timer.clk_rate_cb.notifier_call = sun5i_rate_cb_clkevt;
290 	ce->timer.clk_rate_cb.next = NULL;
291 
292 	ret = clk_notifier_register(clk, &ce->timer.clk_rate_cb);
293 	if (ret) {
294 		pr_err("Unable to register clock notifier.\n");
295 		goto err_disable_clk;
296 	}
297 
298 	ce->clkevt.name = node->name;
299 	ce->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
300 	ce->clkevt.set_next_event = sun5i_clkevt_next_event;
301 	ce->clkevt.set_state_shutdown = sun5i_clkevt_shutdown;
302 	ce->clkevt.set_state_periodic = sun5i_clkevt_set_periodic;
303 	ce->clkevt.set_state_oneshot = sun5i_clkevt_set_oneshot;
304 	ce->clkevt.tick_resume = sun5i_clkevt_shutdown;
305 	ce->clkevt.rating = 340;
306 	ce->clkevt.irq = irq;
307 	ce->clkevt.cpumask = cpu_possible_mask;
308 
309 	/* Enable timer0 interrupt */
310 	val = readl(base + TIMER_IRQ_EN_REG);
311 	writel(val | TIMER_IRQ_EN(0), base + TIMER_IRQ_EN_REG);
312 
313 	clockevents_config_and_register(&ce->clkevt, rate,
314 					TIMER_SYNC_TICKS, 0xffffffff);
315 
316 	ret = request_irq(irq, sun5i_timer_interrupt, IRQF_TIMER | IRQF_IRQPOLL,
317 			  "sun5i_timer0", ce);
318 	if (ret) {
319 		pr_err("Unable to register interrupt\n");
320 		goto err_remove_notifier;
321 	}
322 
323 	return 0;
324 
325 err_remove_notifier:
326 	clk_notifier_unregister(clk, &ce->timer.clk_rate_cb);
327 err_disable_clk:
328 	clk_disable_unprepare(clk);
329 err_free:
330 	kfree(ce);
331 	return ret;
332 }
333 
334 static int __init sun5i_timer_init(struct device_node *node)
335 {
336 	struct reset_control *rstc;
337 	void __iomem *timer_base;
338 	struct clk *clk;
339 	int irq, ret;
340 
341 	timer_base = of_io_request_and_map(node, 0, of_node_full_name(node));
342 	if (IS_ERR(timer_base)) {
343 		pr_err("Can't map registers\n");
344 		return PTR_ERR(timer_base);
345 	}
346 
347 	irq = irq_of_parse_and_map(node, 0);
348 	if (irq <= 0) {
349 		pr_err("Can't parse IRQ\n");
350 		return -EINVAL;
351 	}
352 
353 	clk = of_clk_get(node, 0);
354 	if (IS_ERR(clk)) {
355 		pr_err("Can't get timer clock\n");
356 		return PTR_ERR(clk);
357 	}
358 
359 	rstc = of_reset_control_get(node, NULL);
360 	if (!IS_ERR(rstc))
361 		reset_control_deassert(rstc);
362 
363 	ret = sun5i_setup_clocksource(node, timer_base, clk, irq);
364 	if (ret)
365 		return ret;
366 
367 	return sun5i_setup_clockevent(node, timer_base, clk, irq);
368 }
369 TIMER_OF_DECLARE(sun5i_a13, "allwinner,sun5i-a13-hstimer",
370 			   sun5i_timer_init);
371 TIMER_OF_DECLARE(sun7i_a20, "allwinner,sun7i-a20-hstimer",
372 			   sun5i_timer_init);
373