1 /*
2  * Copyright (C) 2007-2013 Michal Simek <monstr@monstr.eu>
3  * Copyright (C) 2012-2013 Xilinx, Inc.
4  * Copyright (C) 2007-2009 PetaLogix
5  * Copyright (C) 2006 Atmark Techno, Inc.
6  *
7  * This file is subject to the terms and conditions of the GNU General Public
8  * License. See the file "COPYING" in the main directory of this archive
9  * for more details.
10  */
11 
12 #include <linux/interrupt.h>
13 #include <linux/delay.h>
14 #include <linux/sched.h>
15 #include <linux/sched/clock.h>
16 #include <linux/sched_clock.h>
17 #include <linux/clk.h>
18 #include <linux/clockchips.h>
19 #include <linux/of_address.h>
20 #include <linux/of_irq.h>
21 #include <linux/timecounter.h>
22 #include <asm/cpuinfo.h>
23 
24 static void __iomem *timer_baseaddr;
25 
26 static unsigned int freq_div_hz;
27 static unsigned int timer_clock_freq;
28 
29 #define TCSR0	(0x00)
30 #define TLR0	(0x04)
31 #define TCR0	(0x08)
32 #define TCSR1	(0x10)
33 #define TLR1	(0x14)
34 #define TCR1	(0x18)
35 
36 #define TCSR_MDT	(1<<0)
37 #define TCSR_UDT	(1<<1)
38 #define TCSR_GENT	(1<<2)
39 #define TCSR_CAPT	(1<<3)
40 #define TCSR_ARHT	(1<<4)
41 #define TCSR_LOAD	(1<<5)
42 #define TCSR_ENIT	(1<<6)
43 #define TCSR_ENT	(1<<7)
44 #define TCSR_TINT	(1<<8)
45 #define TCSR_PWMA	(1<<9)
46 #define TCSR_ENALL	(1<<10)
47 
48 static unsigned int (*read_fn)(void __iomem *);
49 static void (*write_fn)(u32, void __iomem *);
50 
timer_write32(u32 val,void __iomem * addr)51 static void timer_write32(u32 val, void __iomem *addr)
52 {
53 	iowrite32(val, addr);
54 }
55 
timer_read32(void __iomem * addr)56 static unsigned int timer_read32(void __iomem *addr)
57 {
58 	return ioread32(addr);
59 }
60 
timer_write32_be(u32 val,void __iomem * addr)61 static void timer_write32_be(u32 val, void __iomem *addr)
62 {
63 	iowrite32be(val, addr);
64 }
65 
timer_read32_be(void __iomem * addr)66 static unsigned int timer_read32_be(void __iomem *addr)
67 {
68 	return ioread32be(addr);
69 }
70 
xilinx_timer0_stop(void)71 static inline void xilinx_timer0_stop(void)
72 {
73 	write_fn(read_fn(timer_baseaddr + TCSR0) & ~TCSR_ENT,
74 		 timer_baseaddr + TCSR0);
75 }
76 
xilinx_timer0_start_periodic(unsigned long load_val)77 static inline void xilinx_timer0_start_periodic(unsigned long load_val)
78 {
79 	if (!load_val)
80 		load_val = 1;
81 	/* loading value to timer reg */
82 	write_fn(load_val, timer_baseaddr + TLR0);
83 
84 	/* load the initial value */
85 	write_fn(TCSR_LOAD, timer_baseaddr + TCSR0);
86 
87 	/* see timer data sheet for detail
88 	 * !ENALL - don't enable 'em all
89 	 * !PWMA - disable pwm
90 	 * TINT - clear interrupt status
91 	 * ENT- enable timer itself
92 	 * ENIT - enable interrupt
93 	 * !LOAD - clear the bit to let go
94 	 * ARHT - auto reload
95 	 * !CAPT - no external trigger
96 	 * !GENT - no external signal
97 	 * UDT - set the timer as down counter
98 	 * !MDT0 - generate mode
99 	 */
100 	write_fn(TCSR_TINT|TCSR_ENIT|TCSR_ENT|TCSR_ARHT|TCSR_UDT,
101 		 timer_baseaddr + TCSR0);
102 }
103 
xilinx_timer0_start_oneshot(unsigned long load_val)104 static inline void xilinx_timer0_start_oneshot(unsigned long load_val)
105 {
106 	if (!load_val)
107 		load_val = 1;
108 	/* loading value to timer reg */
109 	write_fn(load_val, timer_baseaddr + TLR0);
110 
111 	/* load the initial value */
112 	write_fn(TCSR_LOAD, timer_baseaddr + TCSR0);
113 
114 	write_fn(TCSR_TINT|TCSR_ENIT|TCSR_ENT|TCSR_ARHT|TCSR_UDT,
115 		 timer_baseaddr + TCSR0);
116 }
117 
xilinx_timer_set_next_event(unsigned long delta,struct clock_event_device * dev)118 static int xilinx_timer_set_next_event(unsigned long delta,
119 					struct clock_event_device *dev)
120 {
121 	pr_debug("%s: next event, delta %x\n", __func__, (u32)delta);
122 	xilinx_timer0_start_oneshot(delta);
123 	return 0;
124 }
125 
xilinx_timer_shutdown(struct clock_event_device * evt)126 static int xilinx_timer_shutdown(struct clock_event_device *evt)
127 {
128 	pr_info("%s\n", __func__);
129 	xilinx_timer0_stop();
130 	return 0;
131 }
132 
xilinx_timer_set_periodic(struct clock_event_device * evt)133 static int xilinx_timer_set_periodic(struct clock_event_device *evt)
134 {
135 	pr_info("%s\n", __func__);
136 	xilinx_timer0_start_periodic(freq_div_hz);
137 	return 0;
138 }
139 
140 static struct clock_event_device clockevent_xilinx_timer = {
141 	.name			= "xilinx_clockevent",
142 	.features		= CLOCK_EVT_FEAT_ONESHOT |
143 				  CLOCK_EVT_FEAT_PERIODIC,
144 	.shift			= 8,
145 	.rating			= 300,
146 	.set_next_event		= xilinx_timer_set_next_event,
147 	.set_state_shutdown	= xilinx_timer_shutdown,
148 	.set_state_periodic	= xilinx_timer_set_periodic,
149 };
150 
timer_ack(void)151 static inline void timer_ack(void)
152 {
153 	write_fn(read_fn(timer_baseaddr + TCSR0), timer_baseaddr + TCSR0);
154 }
155 
timer_interrupt(int irq,void * dev_id)156 static irqreturn_t timer_interrupt(int irq, void *dev_id)
157 {
158 	struct clock_event_device *evt = &clockevent_xilinx_timer;
159 	timer_ack();
160 	evt->event_handler(evt);
161 	return IRQ_HANDLED;
162 }
163 
xilinx_clockevent_init(void)164 static __init int xilinx_clockevent_init(void)
165 {
166 	clockevent_xilinx_timer.mult =
167 		div_sc(timer_clock_freq, NSEC_PER_SEC,
168 				clockevent_xilinx_timer.shift);
169 	clockevent_xilinx_timer.max_delta_ns =
170 		clockevent_delta2ns((u32)~0, &clockevent_xilinx_timer);
171 	clockevent_xilinx_timer.max_delta_ticks = (u32)~0;
172 	clockevent_xilinx_timer.min_delta_ns =
173 		clockevent_delta2ns(1, &clockevent_xilinx_timer);
174 	clockevent_xilinx_timer.min_delta_ticks = 1;
175 	clockevent_xilinx_timer.cpumask = cpumask_of(0);
176 	clockevents_register_device(&clockevent_xilinx_timer);
177 
178 	return 0;
179 }
180 
xilinx_clock_read(void)181 static u64 xilinx_clock_read(void)
182 {
183 	return read_fn(timer_baseaddr + TCR1);
184 }
185 
xilinx_read(struct clocksource * cs)186 static u64 xilinx_read(struct clocksource *cs)
187 {
188 	/* reading actual value of timer 1 */
189 	return (u64)xilinx_clock_read();
190 }
191 
192 static struct timecounter xilinx_tc = {
193 	.cc = NULL,
194 };
195 
xilinx_cc_read(const struct cyclecounter * cc)196 static u64 xilinx_cc_read(const struct cyclecounter *cc)
197 {
198 	return xilinx_read(NULL);
199 }
200 
201 static struct cyclecounter xilinx_cc = {
202 	.read = xilinx_cc_read,
203 	.mask = CLOCKSOURCE_MASK(32),
204 	.shift = 8,
205 };
206 
init_xilinx_timecounter(void)207 static int __init init_xilinx_timecounter(void)
208 {
209 	xilinx_cc.mult = div_sc(timer_clock_freq, NSEC_PER_SEC,
210 				xilinx_cc.shift);
211 
212 	timecounter_init(&xilinx_tc, &xilinx_cc, sched_clock());
213 
214 	return 0;
215 }
216 
217 static struct clocksource clocksource_microblaze = {
218 	.name		= "xilinx_clocksource",
219 	.rating		= 300,
220 	.read		= xilinx_read,
221 	.mask		= CLOCKSOURCE_MASK(32),
222 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
223 };
224 
xilinx_clocksource_init(void)225 static int __init xilinx_clocksource_init(void)
226 {
227 	int ret;
228 
229 	ret = clocksource_register_hz(&clocksource_microblaze,
230 				      timer_clock_freq);
231 	if (ret) {
232 		pr_err("failed to register clocksource");
233 		return ret;
234 	}
235 
236 	/* stop timer1 */
237 	write_fn(read_fn(timer_baseaddr + TCSR1) & ~TCSR_ENT,
238 		 timer_baseaddr + TCSR1);
239 	/* start timer1 - up counting without interrupt */
240 	write_fn(TCSR_TINT|TCSR_ENT|TCSR_ARHT, timer_baseaddr + TCSR1);
241 
242 	/* register timecounter - for ftrace support */
243 	return init_xilinx_timecounter();
244 }
245 
xilinx_timer_init(struct device_node * timer)246 static int __init xilinx_timer_init(struct device_node *timer)
247 {
248 	struct clk *clk;
249 	static int initialized;
250 	u32 irq;
251 	u32 timer_num = 1;
252 	int ret;
253 
254 	/* If this property is present, the device is a PWM and not a timer */
255 	if (of_property_read_bool(timer, "#pwm-cells"))
256 		return 0;
257 
258 	if (initialized)
259 		return -EINVAL;
260 
261 	initialized = 1;
262 
263 	timer_baseaddr = of_iomap(timer, 0);
264 	if (!timer_baseaddr) {
265 		pr_err("ERROR: invalid timer base address\n");
266 		return -ENXIO;
267 	}
268 
269 	write_fn = timer_write32;
270 	read_fn = timer_read32;
271 
272 	write_fn(TCSR_MDT, timer_baseaddr + TCSR0);
273 	if (!(read_fn(timer_baseaddr + TCSR0) & TCSR_MDT)) {
274 		write_fn = timer_write32_be;
275 		read_fn = timer_read32_be;
276 	}
277 
278 	irq = irq_of_parse_and_map(timer, 0);
279 	if (irq <= 0) {
280 		pr_err("Failed to parse and map irq");
281 		return -EINVAL;
282 	}
283 
284 	of_property_read_u32(timer, "xlnx,one-timer-only", &timer_num);
285 	if (timer_num) {
286 		pr_err("Please enable two timers in HW\n");
287 		return -EINVAL;
288 	}
289 
290 	pr_info("%pOF: irq=%d\n", timer, irq);
291 
292 	clk = of_clk_get(timer, 0);
293 	if (IS_ERR(clk)) {
294 		pr_err("ERROR: timer CCF input clock not found\n");
295 		/* If there is clock-frequency property than use it */
296 		of_property_read_u32(timer, "clock-frequency",
297 				    &timer_clock_freq);
298 	} else {
299 		timer_clock_freq = clk_get_rate(clk);
300 	}
301 
302 	if (!timer_clock_freq) {
303 		pr_err("ERROR: Using CPU clock frequency\n");
304 		timer_clock_freq = cpuinfo.cpu_clock_freq;
305 	}
306 
307 	freq_div_hz = timer_clock_freq / HZ;
308 
309 	ret = request_irq(irq, timer_interrupt, IRQF_TIMER, "timer",
310 			  &clockevent_xilinx_timer);
311 	if (ret) {
312 		pr_err("Failed to setup IRQ");
313 		return ret;
314 	}
315 
316 	ret = xilinx_clocksource_init();
317 	if (ret)
318 		return ret;
319 
320 	ret = xilinx_clockevent_init();
321 	if (ret)
322 		return ret;
323 
324 	sched_clock_register(xilinx_clock_read, 32, timer_clock_freq);
325 
326 	return 0;
327 }
328 
329 TIMER_OF_DECLARE(xilinx_timer, "xlnx,xps-timer-1.00.a",
330 		       xilinx_timer_init);
331