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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Faraday Technology FTTMR010 timer driver
4 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
5 *
6 * Based on a rewrite of arch/arm/mach-gemini/timer.c:
7 * Copyright (C) 2001-2006 Storlink, Corp.
8 * Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
9 */
10#include <linux/interrupt.h>
11#include <linux/io.h>
12#include <linux/of.h>
13#include <linux/of_address.h>
14#include <linux/of_irq.h>
15#include <linux/clockchips.h>
16#include <linux/clocksource.h>
17#include <linux/sched_clock.h>
18#include <linux/clk.h>
19#include <linux/slab.h>
20#include <linux/bitops.h>
21#include <linux/delay.h>
22
23/*
24 * Register definitions common for all the timer variants.
25 */
26#define TIMER1_COUNT (0x00)
27#define TIMER1_LOAD (0x04)
28#define TIMER1_MATCH1 (0x08)
29#define TIMER1_MATCH2 (0x0c)
30#define TIMER2_COUNT (0x10)
31#define TIMER2_LOAD (0x14)
32#define TIMER2_MATCH1 (0x18)
33#define TIMER2_MATCH2 (0x1c)
34#define TIMER3_COUNT (0x20)
35#define TIMER3_LOAD (0x24)
36#define TIMER3_MATCH1 (0x28)
37#define TIMER3_MATCH2 (0x2c)
38#define TIMER_CR (0x30)
39
40/*
41 * Control register (TMC30) bit fields for fttmr010/gemini/moxart timers.
42 */
43#define TIMER_1_CR_ENABLE BIT(0)
44#define TIMER_1_CR_CLOCK BIT(1)
45#define TIMER_1_CR_INT BIT(2)
46#define TIMER_2_CR_ENABLE BIT(3)
47#define TIMER_2_CR_CLOCK BIT(4)
48#define TIMER_2_CR_INT BIT(5)
49#define TIMER_3_CR_ENABLE BIT(6)
50#define TIMER_3_CR_CLOCK BIT(7)
51#define TIMER_3_CR_INT BIT(8)
52#define TIMER_1_CR_UPDOWN BIT(9)
53#define TIMER_2_CR_UPDOWN BIT(10)
54#define TIMER_3_CR_UPDOWN BIT(11)
55
56/*
57 * Control register (TMC30) bit fields for aspeed ast2400/ast2500 timers.
58 * The aspeed timers move bits around in the control register and lacks
59 * bits for setting the timer to count upwards.
60 */
61#define TIMER_1_CR_ASPEED_ENABLE BIT(0)
62#define TIMER_1_CR_ASPEED_CLOCK BIT(1)
63#define TIMER_1_CR_ASPEED_INT BIT(2)
64#define TIMER_2_CR_ASPEED_ENABLE BIT(4)
65#define TIMER_2_CR_ASPEED_CLOCK BIT(5)
66#define TIMER_2_CR_ASPEED_INT BIT(6)
67#define TIMER_3_CR_ASPEED_ENABLE BIT(8)
68#define TIMER_3_CR_ASPEED_CLOCK BIT(9)
69#define TIMER_3_CR_ASPEED_INT BIT(10)
70
71/*
72 * Interrupt status/mask register definitions for fttmr010/gemini/moxart
73 * timers.
74 * The registers don't exist and they are not needed on aspeed timers
75 * because:
76 * - aspeed timer overflow interrupt is controlled by bits in Control
77 * Register (TMC30).
78 * - aspeed timers always generate interrupt when either one of the
79 * Match registers equals to Status register.
80 */
81#define TIMER_INTR_STATE (0x34)
82#define TIMER_INTR_MASK (0x38)
83#define TIMER_1_INT_MATCH1 BIT(0)
84#define TIMER_1_INT_MATCH2 BIT(1)
85#define TIMER_1_INT_OVERFLOW BIT(2)
86#define TIMER_2_INT_MATCH1 BIT(3)
87#define TIMER_2_INT_MATCH2 BIT(4)
88#define TIMER_2_INT_OVERFLOW BIT(5)
89#define TIMER_3_INT_MATCH1 BIT(6)
90#define TIMER_3_INT_MATCH2 BIT(7)
91#define TIMER_3_INT_OVERFLOW BIT(8)
92#define TIMER_INT_ALL_MASK 0x1ff
93
94struct fttmr010 {
95 void __iomem *base;
96 unsigned int tick_rate;
97 bool is_aspeed;
98 u32 t1_enable_val;
99 struct clock_event_device clkevt;
100#ifdef CONFIG_ARM
101 struct delay_timer delay_timer;
102#endif
103};
104
105/*
106 * A local singleton used by sched_clock and delay timer reads, which are
107 * fast and stateless
108 */
109static struct fttmr010 *local_fttmr;
110
111static inline struct fttmr010 *to_fttmr010(struct clock_event_device *evt)
112{
113 return container_of(evt, struct fttmr010, clkevt);
114}
115
116static unsigned long fttmr010_read_current_timer_up(void)
117{
118 return readl(local_fttmr->base + TIMER2_COUNT);
119}
120
121static unsigned long fttmr010_read_current_timer_down(void)
122{
123 return ~readl(local_fttmr->base + TIMER2_COUNT);
124}
125
126static u64 notrace fttmr010_read_sched_clock_up(void)
127{
128 return fttmr010_read_current_timer_up();
129}
130
131static u64 notrace fttmr010_read_sched_clock_down(void)
132{
133 return fttmr010_read_current_timer_down();
134}
135
136static int fttmr010_timer_set_next_event(unsigned long cycles,
137 struct clock_event_device *evt)
138{
139 struct fttmr010 *fttmr010 = to_fttmr010(evt);
140 u32 cr;
141
142 /* Stop */
143 cr = readl(fttmr010->base + TIMER_CR);
144 cr &= ~fttmr010->t1_enable_val;
145 writel(cr, fttmr010->base + TIMER_CR);
146
147 if (fttmr010->is_aspeed) {
148 /*
149 * ASPEED Timer Controller will load TIMER1_LOAD register
150 * into TIMER1_COUNT register when the timer is re-enabled.
151 */
152 writel(cycles, fttmr010->base + TIMER1_LOAD);
153 } else {
154 /* Setup the match register forward in time */
155 cr = readl(fttmr010->base + TIMER1_COUNT);
156 writel(cr + cycles, fttmr010->base + TIMER1_MATCH1);
157 }
158
159 /* Start */
160 cr = readl(fttmr010->base + TIMER_CR);
161 cr |= fttmr010->t1_enable_val;
162 writel(cr, fttmr010->base + TIMER_CR);
163
164 return 0;
165}
166
167static int fttmr010_timer_shutdown(struct clock_event_device *evt)
168{
169 struct fttmr010 *fttmr010 = to_fttmr010(evt);
170 u32 cr;
171
172 /* Stop */
173 cr = readl(fttmr010->base + TIMER_CR);
174 cr &= ~fttmr010->t1_enable_val;
175 writel(cr, fttmr010->base + TIMER_CR);
176
177 return 0;
178}
179
180static int fttmr010_timer_set_oneshot(struct clock_event_device *evt)
181{
182 struct fttmr010 *fttmr010 = to_fttmr010(evt);
183 u32 cr;
184
185 /* Stop */
186 cr = readl(fttmr010->base + TIMER_CR);
187 cr &= ~fttmr010->t1_enable_val;
188 writel(cr, fttmr010->base + TIMER_CR);
189
190 /* Setup counter start from 0 or ~0 */
191 writel(0, fttmr010->base + TIMER1_COUNT);
192 if (fttmr010->is_aspeed) {
193 writel(~0, fttmr010->base + TIMER1_LOAD);
194 } else {
195 writel(0, fttmr010->base + TIMER1_LOAD);
196
197 /* Enable interrupt */
198 cr = readl(fttmr010->base + TIMER_INTR_MASK);
199 cr &= ~(TIMER_1_INT_OVERFLOW | TIMER_1_INT_MATCH2);
200 cr |= TIMER_1_INT_MATCH1;
201 writel(cr, fttmr010->base + TIMER_INTR_MASK);
202 }
203
204 return 0;
205}
206
207static int fttmr010_timer_set_periodic(struct clock_event_device *evt)
208{
209 struct fttmr010 *fttmr010 = to_fttmr010(evt);
210 u32 period = DIV_ROUND_CLOSEST(fttmr010->tick_rate, HZ);
211 u32 cr;
212
213 /* Stop */
214 cr = readl(fttmr010->base + TIMER_CR);
215 cr &= ~fttmr010->t1_enable_val;
216 writel(cr, fttmr010->base + TIMER_CR);
217
218 /* Setup timer to fire at 1/HZ intervals. */
219 if (fttmr010->is_aspeed) {
220 writel(period, fttmr010->base + TIMER1_LOAD);
221 } else {
222 cr = 0xffffffff - (period - 1);
223 writel(cr, fttmr010->base + TIMER1_COUNT);
224 writel(cr, fttmr010->base + TIMER1_LOAD);
225
226 /* Enable interrupt on overflow */
227 cr = readl(fttmr010->base + TIMER_INTR_MASK);
228 cr &= ~(TIMER_1_INT_MATCH1 | TIMER_1_INT_MATCH2);
229 cr |= TIMER_1_INT_OVERFLOW;
230 writel(cr, fttmr010->base + TIMER_INTR_MASK);
231 }
232
233 /* Start the timer */
234 cr = readl(fttmr010->base + TIMER_CR);
235 cr |= fttmr010->t1_enable_val;
236 writel(cr, fttmr010->base + TIMER_CR);
237
238 return 0;
239}
240
241/*
242 * IRQ handler for the timer
243 */
244static irqreturn_t fttmr010_timer_interrupt(int irq, void *dev_id)
245{
246 struct clock_event_device *evt = dev_id;
247
248 evt->event_handler(evt);
249 return IRQ_HANDLED;
250}
251
252static int __init fttmr010_common_init(struct device_node *np, bool is_aspeed)
253{
254 struct fttmr010 *fttmr010;
255 int irq;
256 struct clk *clk;
257 int ret;
258 u32 val;
259
260 /*
261 * These implementations require a clock reference.
262 * FIXME: we currently only support clocking using PCLK
263 * and using EXTCLK is not supported in the driver.
264 */
265 clk = of_clk_get_by_name(np, "PCLK");
266 if (IS_ERR(clk)) {
267 pr_err("could not get PCLK\n");
268 return PTR_ERR(clk);
269 }
270 ret = clk_prepare_enable(clk);
271 if (ret) {
272 pr_err("failed to enable PCLK\n");
273 return ret;
274 }
275
276 fttmr010 = kzalloc(sizeof(*fttmr010), GFP_KERNEL);
277 if (!fttmr010) {
278 ret = -ENOMEM;
279 goto out_disable_clock;
280 }
281 fttmr010->tick_rate = clk_get_rate(clk);
282
283 fttmr010->base = of_iomap(np, 0);
284 if (!fttmr010->base) {
285 pr_err("Can't remap registers\n");
286 ret = -ENXIO;
287 goto out_free;
288 }
289 /* IRQ for timer 1 */
290 irq = irq_of_parse_and_map(np, 0);
291 if (irq <= 0) {
292 pr_err("Can't parse IRQ\n");
293 ret = -EINVAL;
294 goto out_unmap;
295 }
296
297 /*
298 * The Aspeed timers move bits around in the control register.
299 */
300 if (is_aspeed) {
301 fttmr010->t1_enable_val = TIMER_1_CR_ASPEED_ENABLE |
302 TIMER_1_CR_ASPEED_INT;
303 fttmr010->is_aspeed = true;
304 } else {
305 fttmr010->t1_enable_val = TIMER_1_CR_ENABLE | TIMER_1_CR_INT;
306
307 /*
308 * Reset the interrupt mask and status
309 */
310 writel(TIMER_INT_ALL_MASK, fttmr010->base + TIMER_INTR_MASK);
311 writel(0, fttmr010->base + TIMER_INTR_STATE);
312 }
313
314 /*
315 * Enable timer 1 count up, timer 2 count up, except on Aspeed,
316 * where everything just counts down.
317 */
318 if (is_aspeed)
319 val = TIMER_2_CR_ASPEED_ENABLE;
320 else {
321 val = TIMER_2_CR_ENABLE | TIMER_1_CR_UPDOWN |
322 TIMER_2_CR_UPDOWN;
323 }
324 writel(val, fttmr010->base + TIMER_CR);
325
326 /*
327 * Setup free-running clocksource timer (interrupts
328 * disabled.)
329 */
330 local_fttmr = fttmr010;
331 writel(0, fttmr010->base + TIMER2_COUNT);
332 writel(0, fttmr010->base + TIMER2_MATCH1);
333 writel(0, fttmr010->base + TIMER2_MATCH2);
334
335 if (fttmr010->is_aspeed) {
336 writel(~0, fttmr010->base + TIMER2_LOAD);
337 clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
338 "FTTMR010-TIMER2",
339 fttmr010->tick_rate,
340 300, 32, clocksource_mmio_readl_down);
341 sched_clock_register(fttmr010_read_sched_clock_down, 32,
342 fttmr010->tick_rate);
343 } else {
344 writel(0, fttmr010->base + TIMER2_LOAD);
345 clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
346 "FTTMR010-TIMER2",
347 fttmr010->tick_rate,
348 300, 32, clocksource_mmio_readl_up);
349 sched_clock_register(fttmr010_read_sched_clock_up, 32,
350 fttmr010->tick_rate);
351 }
352
353 /*
354 * Setup clockevent timer (interrupt-driven) on timer 1.
355 */
356 writel(0, fttmr010->base + TIMER1_COUNT);
357 writel(0, fttmr010->base + TIMER1_LOAD);
358 writel(0, fttmr010->base + TIMER1_MATCH1);
359 writel(0, fttmr010->base + TIMER1_MATCH2);
360 ret = request_irq(irq, fttmr010_timer_interrupt, IRQF_TIMER,
361 "FTTMR010-TIMER1", &fttmr010->clkevt);
362 if (ret) {
363 pr_err("FTTMR010-TIMER1 no IRQ\n");
364 goto out_unmap;
365 }
366
367 fttmr010->clkevt.name = "FTTMR010-TIMER1";
368 /* Reasonably fast and accurate clock event */
369 fttmr010->clkevt.rating = 300;
370 fttmr010->clkevt.features = CLOCK_EVT_FEAT_PERIODIC |
371 CLOCK_EVT_FEAT_ONESHOT;
372 fttmr010->clkevt.set_next_event = fttmr010_timer_set_next_event;
373 fttmr010->clkevt.set_state_shutdown = fttmr010_timer_shutdown;
374 fttmr010->clkevt.set_state_periodic = fttmr010_timer_set_periodic;
375 fttmr010->clkevt.set_state_oneshot = fttmr010_timer_set_oneshot;
376 fttmr010->clkevt.tick_resume = fttmr010_timer_shutdown;
377 fttmr010->clkevt.cpumask = cpumask_of(0);
378 fttmr010->clkevt.irq = irq;
379 clockevents_config_and_register(&fttmr010->clkevt,
380 fttmr010->tick_rate,
381 1, 0xffffffff);
382
383#ifdef CONFIG_ARM
384 /* Also use this timer for delays */
385 if (fttmr010->is_aspeed)
386 fttmr010->delay_timer.read_current_timer =
387 fttmr010_read_current_timer_down;
388 else
389 fttmr010->delay_timer.read_current_timer =
390 fttmr010_read_current_timer_up;
391 fttmr010->delay_timer.freq = fttmr010->tick_rate;
392 register_current_timer_delay(&fttmr010->delay_timer);
393#endif
394
395 return 0;
396
397out_unmap:
398 iounmap(fttmr010->base);
399out_free:
400 kfree(fttmr010);
401out_disable_clock:
402 clk_disable_unprepare(clk);
403
404 return ret;
405}
406
407static __init int aspeed_timer_init(struct device_node *np)
408{
409 return fttmr010_common_init(np, true);
410}
411
412static __init int fttmr010_timer_init(struct device_node *np)
413{
414 return fttmr010_common_init(np, false);
415}
416
417TIMER_OF_DECLARE(fttmr010, "faraday,fttmr010", fttmr010_timer_init);
418TIMER_OF_DECLARE(gemini, "cortina,gemini-timer", fttmr010_timer_init);
419TIMER_OF_DECLARE(moxart, "moxa,moxart-timer", fttmr010_timer_init);
420TIMER_OF_DECLARE(ast2400, "aspeed,ast2400-timer", aspeed_timer_init);
421TIMER_OF_DECLARE(ast2500, "aspeed,ast2500-timer", aspeed_timer_init);