1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Mediatek SoCs General-Purpose Timer handling.
4  *
5  * Copyright (C) 2014 Matthias Brugger
6  *
7  * Matthias Brugger <matthias.bgg@gmail.com>
8  */
9 
10 #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
11 
12 #include <linux/clockchips.h>
13 #include <linux/clocksource.h>
14 #include <linux/interrupt.h>
15 #include <linux/irqreturn.h>
16 #include <linux/sched_clock.h>
17 #include <linux/slab.h>
18 #include "timer-of.h"
19 
20 #define TIMER_CLK_EVT           (1)
21 #define TIMER_CLK_SRC           (2)
22 
23 #define TIMER_SYNC_TICKS        (3)
24 
25 /* gpt */
26 #define GPT_IRQ_EN_REG          0x00
27 #define GPT_IRQ_ENABLE(val)     BIT((val) - 1)
28 #define GPT_IRQ_ACK_REG	        0x08
29 #define GPT_IRQ_ACK(val)        BIT((val) - 1)
30 
31 #define GPT_CTRL_REG(val)       (0x10 * (val))
32 #define GPT_CTRL_OP(val)        (((val) & 0x3) << 4)
33 #define GPT_CTRL_OP_ONESHOT     (0)
34 #define GPT_CTRL_OP_REPEAT      (1)
35 #define GPT_CTRL_OP_FREERUN     (3)
36 #define GPT_CTRL_CLEAR          (2)
37 #define GPT_CTRL_ENABLE         (1)
38 #define GPT_CTRL_DISABLE        (0)
39 
40 #define GPT_CLK_REG(val)        (0x04 + (0x10 * (val)))
41 #define GPT_CLK_SRC(val)        (((val) & 0x1) << 4)
42 #define GPT_CLK_SRC_SYS13M      (0)
43 #define GPT_CLK_SRC_RTC32K      (1)
44 #define GPT_CLK_DIV1            (0x0)
45 #define GPT_CLK_DIV2            (0x1)
46 
47 #define GPT_CNT_REG(val)        (0x08 + (0x10 * (val)))
48 #define GPT_CMP_REG(val)        (0x0C + (0x10 * (val)))
49 
50 /* system timer */
51 #define SYST_BASE               (0x40)
52 
53 #define SYST_CON                (SYST_BASE + 0x0)
54 #define SYST_VAL                (SYST_BASE + 0x4)
55 
56 #define SYST_CON_REG(to)        (timer_of_base(to) + SYST_CON)
57 #define SYST_VAL_REG(to)        (timer_of_base(to) + SYST_VAL)
58 
59 /*
60  * SYST_CON_EN: Clock enable. Shall be set to
61  *   - Start timer countdown.
62  *   - Allow timeout ticks being updated.
63  *   - Allow changing interrupt functions.
64  *
65  * SYST_CON_IRQ_EN: Set to allow interrupt.
66  *
67  * SYST_CON_IRQ_CLR: Set to clear interrupt.
68  */
69 #define SYST_CON_EN              BIT(0)
70 #define SYST_CON_IRQ_EN          BIT(1)
71 #define SYST_CON_IRQ_CLR         BIT(4)
72 
73 static void __iomem *gpt_sched_reg __read_mostly;
74 
75 static void mtk_syst_ack_irq(struct timer_of *to)
76 {
77 	/* Clear and disable interrupt */
78 	writel(SYST_CON_IRQ_CLR | SYST_CON_EN, SYST_CON_REG(to));
79 }
80 
81 static irqreturn_t mtk_syst_handler(int irq, void *dev_id)
82 {
83 	struct clock_event_device *clkevt = dev_id;
84 	struct timer_of *to = to_timer_of(clkevt);
85 
86 	mtk_syst_ack_irq(to);
87 	clkevt->event_handler(clkevt);
88 
89 	return IRQ_HANDLED;
90 }
91 
92 static int mtk_syst_clkevt_next_event(unsigned long ticks,
93 				      struct clock_event_device *clkevt)
94 {
95 	struct timer_of *to = to_timer_of(clkevt);
96 
97 	/* Enable clock to allow timeout tick update later */
98 	writel(SYST_CON_EN, SYST_CON_REG(to));
99 
100 	/*
101 	 * Write new timeout ticks. Timer shall start countdown
102 	 * after timeout ticks are updated.
103 	 */
104 	writel(ticks, SYST_VAL_REG(to));
105 
106 	/* Enable interrupt */
107 	writel(SYST_CON_EN | SYST_CON_IRQ_EN, SYST_CON_REG(to));
108 
109 	return 0;
110 }
111 
112 static int mtk_syst_clkevt_shutdown(struct clock_event_device *clkevt)
113 {
114 	/* Disable timer */
115 	writel(0, SYST_CON_REG(to_timer_of(clkevt)));
116 
117 	return 0;
118 }
119 
120 static int mtk_syst_clkevt_resume(struct clock_event_device *clkevt)
121 {
122 	return mtk_syst_clkevt_shutdown(clkevt);
123 }
124 
125 static int mtk_syst_clkevt_oneshot(struct clock_event_device *clkevt)
126 {
127 	return 0;
128 }
129 
130 static u64 notrace mtk_gpt_read_sched_clock(void)
131 {
132 	return readl_relaxed(gpt_sched_reg);
133 }
134 
135 static void mtk_gpt_clkevt_time_stop(struct timer_of *to, u8 timer)
136 {
137 	u32 val;
138 
139 	val = readl(timer_of_base(to) + GPT_CTRL_REG(timer));
140 	writel(val & ~GPT_CTRL_ENABLE, timer_of_base(to) +
141 	       GPT_CTRL_REG(timer));
142 }
143 
144 static void mtk_gpt_clkevt_time_setup(struct timer_of *to,
145 				      unsigned long delay, u8 timer)
146 {
147 	writel(delay, timer_of_base(to) + GPT_CMP_REG(timer));
148 }
149 
150 static void mtk_gpt_clkevt_time_start(struct timer_of *to,
151 				      bool periodic, u8 timer)
152 {
153 	u32 val;
154 
155 	/* Acknowledge interrupt */
156 	writel(GPT_IRQ_ACK(timer), timer_of_base(to) + GPT_IRQ_ACK_REG);
157 
158 	val = readl(timer_of_base(to) + GPT_CTRL_REG(timer));
159 
160 	/* Clear 2 bit timer operation mode field */
161 	val &= ~GPT_CTRL_OP(0x3);
162 
163 	if (periodic)
164 		val |= GPT_CTRL_OP(GPT_CTRL_OP_REPEAT);
165 	else
166 		val |= GPT_CTRL_OP(GPT_CTRL_OP_ONESHOT);
167 
168 	writel(val | GPT_CTRL_ENABLE | GPT_CTRL_CLEAR,
169 	       timer_of_base(to) + GPT_CTRL_REG(timer));
170 }
171 
172 static int mtk_gpt_clkevt_shutdown(struct clock_event_device *clk)
173 {
174 	mtk_gpt_clkevt_time_stop(to_timer_of(clk), TIMER_CLK_EVT);
175 
176 	return 0;
177 }
178 
179 static int mtk_gpt_clkevt_set_periodic(struct clock_event_device *clk)
180 {
181 	struct timer_of *to = to_timer_of(clk);
182 
183 	mtk_gpt_clkevt_time_stop(to, TIMER_CLK_EVT);
184 	mtk_gpt_clkevt_time_setup(to, to->of_clk.period, TIMER_CLK_EVT);
185 	mtk_gpt_clkevt_time_start(to, true, TIMER_CLK_EVT);
186 
187 	return 0;
188 }
189 
190 static int mtk_gpt_clkevt_next_event(unsigned long event,
191 				     struct clock_event_device *clk)
192 {
193 	struct timer_of *to = to_timer_of(clk);
194 
195 	mtk_gpt_clkevt_time_stop(to, TIMER_CLK_EVT);
196 	mtk_gpt_clkevt_time_setup(to, event, TIMER_CLK_EVT);
197 	mtk_gpt_clkevt_time_start(to, false, TIMER_CLK_EVT);
198 
199 	return 0;
200 }
201 
202 static irqreturn_t mtk_gpt_interrupt(int irq, void *dev_id)
203 {
204 	struct clock_event_device *clkevt = (struct clock_event_device *)dev_id;
205 	struct timer_of *to = to_timer_of(clkevt);
206 
207 	/* Acknowledge timer0 irq */
208 	writel(GPT_IRQ_ACK(TIMER_CLK_EVT), timer_of_base(to) + GPT_IRQ_ACK_REG);
209 	clkevt->event_handler(clkevt);
210 
211 	return IRQ_HANDLED;
212 }
213 
214 static void
215 __init mtk_gpt_setup(struct timer_of *to, u8 timer, u8 option)
216 {
217 	writel(GPT_CTRL_CLEAR | GPT_CTRL_DISABLE,
218 	       timer_of_base(to) + GPT_CTRL_REG(timer));
219 
220 	writel(GPT_CLK_SRC(GPT_CLK_SRC_SYS13M) | GPT_CLK_DIV1,
221 	       timer_of_base(to) + GPT_CLK_REG(timer));
222 
223 	writel(0x0, timer_of_base(to) + GPT_CMP_REG(timer));
224 
225 	writel(GPT_CTRL_OP(option) | GPT_CTRL_ENABLE,
226 	       timer_of_base(to) + GPT_CTRL_REG(timer));
227 }
228 
229 static void mtk_gpt_enable_irq(struct timer_of *to, u8 timer)
230 {
231 	u32 val;
232 
233 	/* Disable all interrupts */
234 	writel(0x0, timer_of_base(to) + GPT_IRQ_EN_REG);
235 
236 	/* Acknowledge all spurious pending interrupts */
237 	writel(0x3f, timer_of_base(to) + GPT_IRQ_ACK_REG);
238 
239 	val = readl(timer_of_base(to) + GPT_IRQ_EN_REG);
240 	writel(val | GPT_IRQ_ENABLE(timer),
241 	       timer_of_base(to) + GPT_IRQ_EN_REG);
242 }
243 
244 static void mtk_gpt_resume(struct clock_event_device *clk)
245 {
246 	struct timer_of *to = to_timer_of(clk);
247 
248 	mtk_gpt_enable_irq(to, TIMER_CLK_EVT);
249 }
250 
251 static void mtk_gpt_suspend(struct clock_event_device *clk)
252 {
253 	struct timer_of *to = to_timer_of(clk);
254 
255 	/* Disable all interrupts */
256 	writel(0x0, timer_of_base(to) + GPT_IRQ_EN_REG);
257 
258 	/*
259 	 * This is called with interrupts disabled,
260 	 * so we need to ack any interrupt that is pending
261 	 * or for example ATF will prevent a suspend from completing.
262 	 */
263 	writel(0x3f, timer_of_base(to) + GPT_IRQ_ACK_REG);
264 }
265 
266 static struct timer_of to = {
267 	.flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,
268 
269 	.clkevt = {
270 		.name = "mtk-clkevt",
271 		.rating = 300,
272 		.cpumask = cpu_possible_mask,
273 	},
274 
275 	.of_irq = {
276 		.flags = IRQF_TIMER | IRQF_IRQPOLL,
277 	},
278 };
279 
280 static int __init mtk_syst_init(struct device_node *node)
281 {
282 	int ret;
283 
284 	to.clkevt.features = CLOCK_EVT_FEAT_DYNIRQ | CLOCK_EVT_FEAT_ONESHOT;
285 	to.clkevt.set_state_shutdown = mtk_syst_clkevt_shutdown;
286 	to.clkevt.set_state_oneshot = mtk_syst_clkevt_oneshot;
287 	to.clkevt.tick_resume = mtk_syst_clkevt_resume;
288 	to.clkevt.set_next_event = mtk_syst_clkevt_next_event;
289 	to.of_irq.handler = mtk_syst_handler;
290 
291 	ret = timer_of_init(node, &to);
292 	if (ret)
293 		return ret;
294 
295 	clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
296 					TIMER_SYNC_TICKS, 0xffffffff);
297 
298 	return 0;
299 }
300 
301 static int __init mtk_gpt_init(struct device_node *node)
302 {
303 	int ret;
304 
305 	to.clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
306 	to.clkevt.set_state_shutdown = mtk_gpt_clkevt_shutdown;
307 	to.clkevt.set_state_periodic = mtk_gpt_clkevt_set_periodic;
308 	to.clkevt.set_state_oneshot = mtk_gpt_clkevt_shutdown;
309 	to.clkevt.tick_resume = mtk_gpt_clkevt_shutdown;
310 	to.clkevt.set_next_event = mtk_gpt_clkevt_next_event;
311 	to.clkevt.suspend = mtk_gpt_suspend;
312 	to.clkevt.resume = mtk_gpt_resume;
313 	to.of_irq.handler = mtk_gpt_interrupt;
314 
315 	ret = timer_of_init(node, &to);
316 	if (ret)
317 		return ret;
318 
319 	/* Configure clock source */
320 	mtk_gpt_setup(&to, TIMER_CLK_SRC, GPT_CTRL_OP_FREERUN);
321 	clocksource_mmio_init(timer_of_base(&to) + GPT_CNT_REG(TIMER_CLK_SRC),
322 			      node->name, timer_of_rate(&to), 300, 32,
323 			      clocksource_mmio_readl_up);
324 	gpt_sched_reg = timer_of_base(&to) + GPT_CNT_REG(TIMER_CLK_SRC);
325 	sched_clock_register(mtk_gpt_read_sched_clock, 32, timer_of_rate(&to));
326 
327 	/* Configure clock event */
328 	mtk_gpt_setup(&to, TIMER_CLK_EVT, GPT_CTRL_OP_REPEAT);
329 	clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
330 					TIMER_SYNC_TICKS, 0xffffffff);
331 
332 	mtk_gpt_enable_irq(&to, TIMER_CLK_EVT);
333 
334 	return 0;
335 }
336 TIMER_OF_DECLARE(mtk_mt6577, "mediatek,mt6577-timer", mtk_gpt_init);
337 TIMER_OF_DECLARE(mtk_mt6765, "mediatek,mt6765-timer", mtk_syst_init);
338