1 /*
2  * Marvell Armada 370/XP SoC timer handling.
3  *
4  * Copyright (C) 2012 Marvell
5  *
6  * Lior Amsalem <alior@marvell.com>
7  * Gregory CLEMENT <gregory.clement@free-electrons.com>
8  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
9  *
10  * This file is licensed under the terms of the GNU General Public
11  * License version 2.  This program is licensed "as is" without any
12  * warranty of any kind, whether express or implied.
13  *
14  * Timer 0 is used as free-running clocksource, while timer 1 is
15  * used as clock_event_device.
16  *
17  * ---
18  * Clocksource driver for Armada 370 and Armada XP SoC.
19  * This driver implements one compatible string for each SoC, given
20  * each has its own characteristics:
21  *
22  *   * Armada 370 has no 25 MHz fixed timer.
23  *
24  *   * Armada XP cannot work properly without such 25 MHz fixed timer as
25  *     doing otherwise leads to using a clocksource whose frequency varies
26  *     when doing cpufreq frequency changes.
27  *
28  * See Documentation/devicetree/bindings/timer/marvell,armada-370-xp-timer.txt
29  */
30 
31 #include <linux/init.h>
32 #include <linux/platform_device.h>
33 #include <linux/kernel.h>
34 #include <linux/clk.h>
35 #include <linux/cpu.h>
36 #include <linux/timer.h>
37 #include <linux/clockchips.h>
38 #include <linux/interrupt.h>
39 #include <linux/of.h>
40 #include <linux/of_irq.h>
41 #include <linux/of_address.h>
42 #include <linux/irq.h>
43 #include <linux/module.h>
44 #include <linux/sched_clock.h>
45 #include <linux/percpu.h>
46 #include <linux/syscore_ops.h>
47 
48 #include <asm/delay.h>
49 
50 /*
51  * Timer block registers.
52  */
53 #define TIMER_CTRL_OFF		0x0000
54 #define  TIMER0_EN		 BIT(0)
55 #define  TIMER0_RELOAD_EN	 BIT(1)
56 #define  TIMER0_25MHZ            BIT(11)
57 #define  TIMER0_DIV(div)         ((div) << 19)
58 #define  TIMER1_EN		 BIT(2)
59 #define  TIMER1_RELOAD_EN	 BIT(3)
60 #define  TIMER1_25MHZ            BIT(12)
61 #define  TIMER1_DIV(div)         ((div) << 22)
62 #define TIMER_EVENTS_STATUS	0x0004
63 #define  TIMER0_CLR_MASK         (~0x1)
64 #define  TIMER1_CLR_MASK         (~0x100)
65 #define TIMER0_RELOAD_OFF	0x0010
66 #define TIMER0_VAL_OFF		0x0014
67 #define TIMER1_RELOAD_OFF	0x0018
68 #define TIMER1_VAL_OFF		0x001c
69 
70 #define LCL_TIMER_EVENTS_STATUS	0x0028
71 /* Global timers are connected to the coherency fabric clock, and the
72    below divider reduces their incrementing frequency. */
73 #define TIMER_DIVIDER_SHIFT     5
74 #define TIMER_DIVIDER           (1 << TIMER_DIVIDER_SHIFT)
75 
76 /*
77  * SoC-specific data.
78  */
79 static void __iomem *timer_base, *local_base;
80 static unsigned int timer_clk;
81 static bool timer25Mhz = true;
82 static u32 enable_mask;
83 
84 /*
85  * Number of timer ticks per jiffy.
86  */
87 static u32 ticks_per_jiffy;
88 
89 static struct clock_event_device __percpu *armada_370_xp_evt;
90 
91 static void local_timer_ctrl_clrset(u32 clr, u32 set)
92 {
93 	writel((readl(local_base + TIMER_CTRL_OFF) & ~clr) | set,
94 		local_base + TIMER_CTRL_OFF);
95 }
96 
97 static u64 notrace armada_370_xp_read_sched_clock(void)
98 {
99 	return ~readl(timer_base + TIMER0_VAL_OFF);
100 }
101 
102 /*
103  * Clockevent handling.
104  */
105 static int
106 armada_370_xp_clkevt_next_event(unsigned long delta,
107 				struct clock_event_device *dev)
108 {
109 	/*
110 	 * Clear clockevent timer interrupt.
111 	 */
112 	writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
113 
114 	/*
115 	 * Setup new clockevent timer value.
116 	 */
117 	writel(delta, local_base + TIMER0_VAL_OFF);
118 
119 	/*
120 	 * Enable the timer.
121 	 */
122 	local_timer_ctrl_clrset(TIMER0_RELOAD_EN, enable_mask);
123 	return 0;
124 }
125 
126 static int armada_370_xp_clkevt_shutdown(struct clock_event_device *evt)
127 {
128 	/*
129 	 * Disable timer.
130 	 */
131 	local_timer_ctrl_clrset(TIMER0_EN, 0);
132 
133 	/*
134 	 * ACK pending timer interrupt.
135 	 */
136 	writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
137 	return 0;
138 }
139 
140 static int armada_370_xp_clkevt_set_periodic(struct clock_event_device *evt)
141 {
142 	/*
143 	 * Setup timer to fire at 1/HZ intervals.
144 	 */
145 	writel(ticks_per_jiffy - 1, local_base + TIMER0_RELOAD_OFF);
146 	writel(ticks_per_jiffy - 1, local_base + TIMER0_VAL_OFF);
147 
148 	/*
149 	 * Enable timer.
150 	 */
151 	local_timer_ctrl_clrset(0, TIMER0_RELOAD_EN | enable_mask);
152 	return 0;
153 }
154 
155 static int armada_370_xp_clkevt_irq;
156 
157 static irqreturn_t armada_370_xp_timer_interrupt(int irq, void *dev_id)
158 {
159 	/*
160 	 * ACK timer interrupt and call event handler.
161 	 */
162 	struct clock_event_device *evt = dev_id;
163 
164 	writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
165 	evt->event_handler(evt);
166 
167 	return IRQ_HANDLED;
168 }
169 
170 /*
171  * Setup the local clock events for a CPU.
172  */
173 static int armada_370_xp_timer_starting_cpu(unsigned int cpu)
174 {
175 	struct clock_event_device *evt = per_cpu_ptr(armada_370_xp_evt, cpu);
176 	u32 clr = 0, set = 0;
177 
178 	if (timer25Mhz)
179 		set = TIMER0_25MHZ;
180 	else
181 		clr = TIMER0_25MHZ;
182 	local_timer_ctrl_clrset(clr, set);
183 
184 	evt->name		= "armada_370_xp_per_cpu_tick",
185 	evt->features		= CLOCK_EVT_FEAT_ONESHOT |
186 				  CLOCK_EVT_FEAT_PERIODIC;
187 	evt->shift		= 32,
188 	evt->rating		= 300,
189 	evt->set_next_event	= armada_370_xp_clkevt_next_event,
190 	evt->set_state_shutdown	= armada_370_xp_clkevt_shutdown;
191 	evt->set_state_periodic	= armada_370_xp_clkevt_set_periodic;
192 	evt->set_state_oneshot	= armada_370_xp_clkevt_shutdown;
193 	evt->tick_resume	= armada_370_xp_clkevt_shutdown;
194 	evt->irq		= armada_370_xp_clkevt_irq;
195 	evt->cpumask		= cpumask_of(cpu);
196 
197 	clockevents_config_and_register(evt, timer_clk, 1, 0xfffffffe);
198 	enable_percpu_irq(evt->irq, 0);
199 
200 	return 0;
201 }
202 
203 static int armada_370_xp_timer_dying_cpu(unsigned int cpu)
204 {
205 	struct clock_event_device *evt = per_cpu_ptr(armada_370_xp_evt, cpu);
206 
207 	evt->set_state_shutdown(evt);
208 	disable_percpu_irq(evt->irq);
209 	return 0;
210 }
211 
212 static u32 timer0_ctrl_reg, timer0_local_ctrl_reg;
213 
214 static int armada_370_xp_timer_suspend(void)
215 {
216 	timer0_ctrl_reg = readl(timer_base + TIMER_CTRL_OFF);
217 	timer0_local_ctrl_reg = readl(local_base + TIMER_CTRL_OFF);
218 	return 0;
219 }
220 
221 static void armada_370_xp_timer_resume(void)
222 {
223 	writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
224 	writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
225 	writel(timer0_ctrl_reg, timer_base + TIMER_CTRL_OFF);
226 	writel(timer0_local_ctrl_reg, local_base + TIMER_CTRL_OFF);
227 }
228 
229 static struct syscore_ops armada_370_xp_timer_syscore_ops = {
230 	.suspend	= armada_370_xp_timer_suspend,
231 	.resume		= armada_370_xp_timer_resume,
232 };
233 
234 static unsigned long armada_370_delay_timer_read(void)
235 {
236 	return ~readl(timer_base + TIMER0_VAL_OFF);
237 }
238 
239 static struct delay_timer armada_370_delay_timer = {
240 	.read_current_timer = armada_370_delay_timer_read,
241 };
242 
243 static int __init armada_370_xp_timer_common_init(struct device_node *np)
244 {
245 	u32 clr = 0, set = 0;
246 	int res;
247 
248 	timer_base = of_iomap(np, 0);
249 	if (!timer_base) {
250 		pr_err("Failed to iomap\n");
251 		return -ENXIO;
252 	}
253 
254 	local_base = of_iomap(np, 1);
255 	if (!local_base) {
256 		pr_err("Failed to iomap\n");
257 		return -ENXIO;
258 	}
259 
260 	if (timer25Mhz) {
261 		set = TIMER0_25MHZ;
262 		enable_mask = TIMER0_EN;
263 	} else {
264 		clr = TIMER0_25MHZ;
265 		enable_mask = TIMER0_EN | TIMER0_DIV(TIMER_DIVIDER_SHIFT);
266 	}
267 	atomic_io_modify(timer_base + TIMER_CTRL_OFF, clr | set, set);
268 	local_timer_ctrl_clrset(clr, set);
269 
270 	/*
271 	 * We use timer 0 as clocksource, and private(local) timer 0
272 	 * for clockevents
273 	 */
274 	armada_370_xp_clkevt_irq = irq_of_parse_and_map(np, 4);
275 
276 	ticks_per_jiffy = (timer_clk + HZ / 2) / HZ;
277 
278 	/*
279 	 * Setup free-running clocksource timer (interrupts
280 	 * disabled).
281 	 */
282 	writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
283 	writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
284 
285 	atomic_io_modify(timer_base + TIMER_CTRL_OFF,
286 		TIMER0_RELOAD_EN | enable_mask,
287 		TIMER0_RELOAD_EN | enable_mask);
288 
289 	armada_370_delay_timer.freq = timer_clk;
290 	register_current_timer_delay(&armada_370_delay_timer);
291 
292 	/*
293 	 * Set scale and timer for sched_clock.
294 	 */
295 	sched_clock_register(armada_370_xp_read_sched_clock, 32, timer_clk);
296 
297 	res = clocksource_mmio_init(timer_base + TIMER0_VAL_OFF,
298 				    "armada_370_xp_clocksource",
299 				    timer_clk, 300, 32, clocksource_mmio_readl_down);
300 	if (res) {
301 		pr_err("Failed to initialize clocksource mmio\n");
302 		return res;
303 	}
304 
305 	armada_370_xp_evt = alloc_percpu(struct clock_event_device);
306 	if (!armada_370_xp_evt)
307 		return -ENOMEM;
308 
309 	/*
310 	 * Setup clockevent timer (interrupt-driven).
311 	 */
312 	res = request_percpu_irq(armada_370_xp_clkevt_irq,
313 				armada_370_xp_timer_interrupt,
314 				"armada_370_xp_per_cpu_tick",
315 				armada_370_xp_evt);
316 	/* Immediately configure the timer on the boot CPU */
317 	if (res) {
318 		pr_err("Failed to request percpu irq\n");
319 		return res;
320 	}
321 
322 	res = cpuhp_setup_state(CPUHP_AP_ARMADA_TIMER_STARTING,
323 				"clockevents/armada:starting",
324 				armada_370_xp_timer_starting_cpu,
325 				armada_370_xp_timer_dying_cpu);
326 	if (res) {
327 		pr_err("Failed to setup hotplug state and timer\n");
328 		return res;
329 	}
330 
331 	register_syscore_ops(&armada_370_xp_timer_syscore_ops);
332 
333 	return 0;
334 }
335 
336 static int __init armada_xp_timer_init(struct device_node *np)
337 {
338 	struct clk *clk = of_clk_get_by_name(np, "fixed");
339 	int ret;
340 
341 	if (IS_ERR(clk)) {
342 		pr_err("Failed to get clock\n");
343 		return PTR_ERR(clk);
344 	}
345 
346 	ret = clk_prepare_enable(clk);
347 	if (ret)
348 		return ret;
349 
350 	timer_clk = clk_get_rate(clk);
351 
352 	return armada_370_xp_timer_common_init(np);
353 }
354 TIMER_OF_DECLARE(armada_xp, "marvell,armada-xp-timer",
355 		       armada_xp_timer_init);
356 
357 static int __init armada_375_timer_init(struct device_node *np)
358 {
359 	struct clk *clk;
360 	int ret;
361 
362 	clk = of_clk_get_by_name(np, "fixed");
363 	if (!IS_ERR(clk)) {
364 		ret = clk_prepare_enable(clk);
365 		if (ret)
366 			return ret;
367 		timer_clk = clk_get_rate(clk);
368 	} else {
369 
370 		/*
371 		 * This fallback is required in order to retain proper
372 		 * devicetree backwards compatibility.
373 		 */
374 		clk = of_clk_get(np, 0);
375 
376 		/* Must have at least a clock */
377 		if (IS_ERR(clk)) {
378 			pr_err("Failed to get clock\n");
379 			return PTR_ERR(clk);
380 		}
381 
382 		ret = clk_prepare_enable(clk);
383 		if (ret)
384 			return ret;
385 
386 		timer_clk = clk_get_rate(clk) / TIMER_DIVIDER;
387 		timer25Mhz = false;
388 	}
389 
390 	return armada_370_xp_timer_common_init(np);
391 }
392 TIMER_OF_DECLARE(armada_375, "marvell,armada-375-timer",
393 		       armada_375_timer_init);
394 
395 static int __init armada_370_timer_init(struct device_node *np)
396 {
397 	struct clk *clk;
398 	int ret;
399 
400 	clk = of_clk_get(np, 0);
401 	if (IS_ERR(clk)) {
402 		pr_err("Failed to get clock\n");
403 		return PTR_ERR(clk);
404 	}
405 
406 	ret = clk_prepare_enable(clk);
407 	if (ret)
408 		return ret;
409 
410 	timer_clk = clk_get_rate(clk) / TIMER_DIVIDER;
411 	timer25Mhz = false;
412 
413 	return armada_370_xp_timer_common_init(np);
414 }
415 TIMER_OF_DECLARE(armada_370, "marvell,armada-370-timer",
416 		       armada_370_timer_init);
417