projects/linux·blob master · refs

434 lines · 11.5 KiB

1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Freescale General-purpose Timers Module
4 *
5 * Copyright (c) Freescale Semiconductor, Inc. 2006.
6 * Shlomi Gridish <[email protected]>
7 * Jerry Huang <[email protected]>
8 * Copyright (c) MontaVista Software, Inc. 2008.
9 * Anton Vorontsov <[email protected]>
10 */
11
12#include <linux/kernel.h>
13#include <linux/err.h>
14#include <linux/errno.h>
15#include <linux/list.h>
16#include <linux/io.h>
17#include <linux/of.h>
18#include <linux/of_address.h>
19#include <linux/of_irq.h>
20#include <linux/spinlock.h>
21#include <linux/bitops.h>
22#include <linux/slab.h>
23#include <linux/export.h>
24#include <asm/fsl_gtm.h>
25
26#define GTCFR_STP(x) ((x) & 1 ? 1 << 5 : 1 << 1)
27#define GTCFR_RST(x) ((x) & 1 ? 1 << 4 : 1 << 0)
28
29#define GTMDR_ICLK_MASK (3 << 1)
30#define GTMDR_ICLK_ICAS (0 << 1)
31#define GTMDR_ICLK_ICLK (1 << 1)
32#define GTMDR_ICLK_SLGO (2 << 1)
33#define GTMDR_FRR (1 << 3)
34#define GTMDR_ORI (1 << 4)
35#define GTMDR_SPS(x) ((x) << 8)
36
37struct gtm_timers_regs {
38 u8 gtcfr1; /* Timer 1, Timer 2 global config register */
39 u8 res0[0x3];
40 u8 gtcfr2; /* Timer 3, timer 4 global config register */
41 u8 res1[0xB];
42 __be16 gtmdr1; /* Timer 1 mode register */
43 __be16 gtmdr2; /* Timer 2 mode register */
44 __be16 gtrfr1; /* Timer 1 reference register */
45 __be16 gtrfr2; /* Timer 2 reference register */
46 __be16 gtcpr1; /* Timer 1 capture register */
47 __be16 gtcpr2; /* Timer 2 capture register */
48 __be16 gtcnr1; /* Timer 1 counter */
49 __be16 gtcnr2; /* Timer 2 counter */
50 __be16 gtmdr3; /* Timer 3 mode register */
51 __be16 gtmdr4; /* Timer 4 mode register */
52 __be16 gtrfr3; /* Timer 3 reference register */
53 __be16 gtrfr4; /* Timer 4 reference register */
54 __be16 gtcpr3; /* Timer 3 capture register */
55 __be16 gtcpr4; /* Timer 4 capture register */
56 __be16 gtcnr3; /* Timer 3 counter */
57 __be16 gtcnr4; /* Timer 4 counter */
58 __be16 gtevr1; /* Timer 1 event register */
59 __be16 gtevr2; /* Timer 2 event register */
60 __be16 gtevr3; /* Timer 3 event register */
61 __be16 gtevr4; /* Timer 4 event register */
62 __be16 gtpsr1; /* Timer 1 prescale register */
63 __be16 gtpsr2; /* Timer 2 prescale register */
64 __be16 gtpsr3; /* Timer 3 prescale register */
65 __be16 gtpsr4; /* Timer 4 prescale register */
66 u8 res2[0x40];
67} __attribute__ ((packed));
68
69struct gtm {
70 unsigned int clock;
71 struct gtm_timers_regs __iomem *regs;
72 struct gtm_timer timers[4];
73 spinlock_t lock;
74 struct list_head list_node;
75};
76
77static LIST_HEAD(gtms);
78
79/**
80 * gtm_get_timer16 - request GTM timer to use it with the rest of GTM API
81 * Context: non-IRQ
82 *
83 * This function reserves GTM timer for later use. It returns gtm_timer
84 * structure to use with the rest of GTM API, you should use timer->irq
85 * to manage timer interrupt.
86 */
87struct gtm_timer *gtm_get_timer16(void)
88{
89 struct gtm *gtm;
90 int i;
91
92 list_for_each_entry(gtm, &gtms, list_node) {
93 spin_lock_irq(&gtm->lock);
94
95 for (i = 0; i < ARRAY_SIZE(gtm->timers); i++) {
96 if (!gtm->timers[i].requested) {
97 gtm->timers[i].requested = true;
98 spin_unlock_irq(&gtm->lock);
99 return &gtm->timers[i];
100 }
101 }
102
103 spin_unlock_irq(&gtm->lock);
104 }
105
106 if (!list_empty(&gtms))
107 return ERR_PTR(-EBUSY);
108 return ERR_PTR(-ENODEV);
109}
110EXPORT_SYMBOL(gtm_get_timer16);
111
112/**
113 * gtm_get_specific_timer16 - request specific GTM timer
114 * @gtm: specific GTM, pass here GTM's device_node->data
115 * @timer: specific timer number, Timer1 is 0.
116 * Context: non-IRQ
117 *
118 * This function reserves GTM timer for later use. It returns gtm_timer
119 * structure to use with the rest of GTM API, you should use timer->irq
120 * to manage timer interrupt.
121 */
122struct gtm_timer *gtm_get_specific_timer16(struct gtm *gtm,
123 unsigned int timer)
124{
125 struct gtm_timer *ret = ERR_PTR(-EBUSY);
126
127 if (timer > 3)
128 return ERR_PTR(-EINVAL);
129
130 spin_lock_irq(&gtm->lock);
131
132 if (gtm->timers[timer].requested)
133 goto out;
134
135 ret = &gtm->timers[timer];
136 ret->requested = true;
137
138out:
139 spin_unlock_irq(&gtm->lock);
140 return ret;
141}
142EXPORT_SYMBOL(gtm_get_specific_timer16);
143
144/**
145 * gtm_put_timer16 - release 16 bits GTM timer
146 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer
147 * Context: any
148 *
149 * This function releases GTM timer so others may request it.
150 */
151void gtm_put_timer16(struct gtm_timer *tmr)
152{
153 gtm_stop_timer16(tmr);
154
155 spin_lock_irq(&tmr->gtm->lock);
156 tmr->requested = false;
157 spin_unlock_irq(&tmr->gtm->lock);
158}
159EXPORT_SYMBOL(gtm_put_timer16);
160
161/*
162 * This is back-end for the exported functions, it's used to reset single
163 * timer in reference mode.
164 */
165static int gtm_set_ref_timer16(struct gtm_timer *tmr, int frequency,
166 int reference_value, bool free_run)
167{
168 struct gtm *gtm = tmr->gtm;
169 int num = tmr - &gtm->timers[0];
170 unsigned int prescaler;
171 u8 iclk = GTMDR_ICLK_ICLK;
172 u8 psr;
173 u8 sps;
174 unsigned long flags;
175 int max_prescaler = 256 * 256 * 16;
176
177 /* CPM2 doesn't have primary prescaler */
178 if (!tmr->gtpsr)
179 max_prescaler /= 256;
180
181 prescaler = gtm->clock / frequency;
182 /*
183 * We have two 8 bit prescalers -- primary and secondary (psr, sps),
184 * plus "slow go" mode (clk / 16). So, total prescale value is
185 * 16 * (psr + 1) * (sps + 1). Though, for CPM2 GTMs we losing psr.
186 */
187 if (prescaler > max_prescaler)
188 return -EINVAL;
189
190 if (prescaler > max_prescaler / 16) {
191 iclk = GTMDR_ICLK_SLGO;
192 prescaler /= 16;
193 }
194
195 if (prescaler <= 256) {
196 psr = 0;
197 sps = prescaler - 1;
198 } else {
199 psr = 256 - 1;
200 sps = prescaler / 256 - 1;
201 }
202
203 spin_lock_irqsave(&gtm->lock, flags);
204
205 /*
206 * Properly reset timers: stop, reset, set up prescalers, reference
207 * value and clear event register.
208 */
209 clrsetbits_8(tmr->gtcfr, ~(GTCFR_STP(num) | GTCFR_RST(num)),
210 GTCFR_STP(num) | GTCFR_RST(num));
211
212 setbits8(tmr->gtcfr, GTCFR_STP(num));
213
214 if (tmr->gtpsr)
215 out_be16(tmr->gtpsr, psr);
216 clrsetbits_be16(tmr->gtmdr, 0xFFFF, iclk | GTMDR_SPS(sps) |
217 GTMDR_ORI | (free_run ? GTMDR_FRR : 0));
218 out_be16(tmr->gtcnr, 0);
219 out_be16(tmr->gtrfr, reference_value);
220 out_be16(tmr->gtevr, 0xFFFF);
221
222 /* Let it be. */
223 clrbits8(tmr->gtcfr, GTCFR_STP(num));
224
225 spin_unlock_irqrestore(&gtm->lock, flags);
226
227 return 0;
228}
229
230/**
231 * gtm_set_timer16 - (re)set 16 bit timer with arbitrary precision
232 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer
233 * @usec: timer interval in microseconds
234 * @reload: if set, the timer will reset upon expiry rather than
235 * continue running free.
236 * Context: any
237 *
238 * This function (re)sets the GTM timer so that it counts up to the requested
239 * interval value, and fires the interrupt when the value is reached. This
240 * function will reduce the precision of the timer as needed in order for the
241 * requested timeout to fit in a 16-bit register.
242 */
243int gtm_set_timer16(struct gtm_timer *tmr, unsigned long usec, bool reload)
244{
245 /* quite obvious, frequency which is enough for µSec precision */
246 int freq = 1000000;
247 unsigned int bit;
248
249 bit = fls_long(usec);
250 if (bit > 15) {
251 freq >>= bit - 15;
252 usec >>= bit - 15;
253 }
254
255 if (!freq)
256 return -EINVAL;
257
258 return gtm_set_ref_timer16(tmr, freq, usec, reload);
259}
260EXPORT_SYMBOL(gtm_set_timer16);
261
262/**
263 * gtm_set_exact_timer16 - (re)set 16 bits timer
264 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer
265 * @usec: timer interval in microseconds
266 * @reload: if set, the timer will reset upon expiry rather than
267 * continue running free.
268 * Context: any
269 *
270 * This function (re)sets GTM timer so that it counts up to the requested
271 * interval value, and fires the interrupt when the value is reached. If reload
272 * flag was set, timer will also reset itself upon reference value, otherwise
273 * it continues to increment.
274 *
275 * The _exact_ bit in the function name states that this function will not
276 * crop precision of the "usec" argument, thus usec is limited to 16 bits
277 * (single timer width).
278 */
279int gtm_set_exact_timer16(struct gtm_timer *tmr, u16 usec, bool reload)
280{
281 /* quite obvious, frequency which is enough for µSec precision */
282 const int freq = 1000000;
283
284 /*
285 * We can lower the frequency (and probably power consumption) by
286 * dividing both frequency and usec by 2 until there is no remainder.
287 * But we won't bother with this unless savings are measured, so just
288 * run the timer as is.
289 */
290
291 return gtm_set_ref_timer16(tmr, freq, usec, reload);
292}
293EXPORT_SYMBOL(gtm_set_exact_timer16);
294
295/**
296 * gtm_stop_timer16 - stop single timer
297 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer
298 * Context: any
299 *
300 * This function simply stops the GTM timer.
301 */
302void gtm_stop_timer16(struct gtm_timer *tmr)
303{
304 struct gtm *gtm = tmr->gtm;
305 int num = tmr - &gtm->timers[0];
306 unsigned long flags;
307
308 spin_lock_irqsave(&gtm->lock, flags);
309
310 setbits8(tmr->gtcfr, GTCFR_STP(num));
311 out_be16(tmr->gtevr, 0xFFFF);
312
313 spin_unlock_irqrestore(&gtm->lock, flags);
314}
315EXPORT_SYMBOL(gtm_stop_timer16);
316
317/**
318 * gtm_ack_timer16 - acknowledge timer event (free-run timers only)
319 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer
320 * @events: events mask to ack
321 * Context: any
322 *
323 * Thus function used to acknowledge timer interrupt event, use it inside the
324 * interrupt handler.
325 */
326void gtm_ack_timer16(struct gtm_timer *tmr, u16 events)
327{
328 out_be16(tmr->gtevr, events);
329}
330EXPORT_SYMBOL(gtm_ack_timer16);
331
332static void __init gtm_set_shortcuts(struct device_node *np,
333 struct gtm_timer *timers,
334 struct gtm_timers_regs __iomem *regs)
335{
336 /*
337 * Yeah, I don't like this either, but timers' registers a bit messed,
338 * so we have to provide shortcuts to write timer independent code.
339 * Alternative option is to create gt*() accessors, but that will be
340 * even uglier and cryptic.
341 */
342 timers[0].gtcfr = &regs->gtcfr1;
343 timers[0].gtmdr = &regs->gtmdr1;
344 timers[0].gtcnr = &regs->gtcnr1;
345 timers[0].gtrfr = &regs->gtrfr1;
346 timers[0].gtevr = &regs->gtevr1;
347
348 timers[1].gtcfr = &regs->gtcfr1;
349 timers[1].gtmdr = &regs->gtmdr2;
350 timers[1].gtcnr = &regs->gtcnr2;
351 timers[1].gtrfr = &regs->gtrfr2;
352 timers[1].gtevr = &regs->gtevr2;
353
354 timers[2].gtcfr = &regs->gtcfr2;
355 timers[2].gtmdr = &regs->gtmdr3;
356 timers[2].gtcnr = &regs->gtcnr3;
357 timers[2].gtrfr = &regs->gtrfr3;
358 timers[2].gtevr = &regs->gtevr3;
359
360 timers[3].gtcfr = &regs->gtcfr2;
361 timers[3].gtmdr = &regs->gtmdr4;
362 timers[3].gtcnr = &regs->gtcnr4;
363 timers[3].gtrfr = &regs->gtrfr4;
364 timers[3].gtevr = &regs->gtevr4;
365
366 /* CPM2 doesn't have primary prescaler */
367 if (!of_device_is_compatible(np, "fsl,cpm2-gtm")) {
368 timers[0].gtpsr = &regs->gtpsr1;
369 timers[1].gtpsr = &regs->gtpsr2;
370 timers[2].gtpsr = &regs->gtpsr3;
371 timers[3].gtpsr = &regs->gtpsr4;
372 }
373}
374
375static int __init fsl_gtm_init(void)
376{
377 struct device_node *np;
378
379 for_each_compatible_node(np, NULL, "fsl,gtm") {
380 int i;
381 struct gtm *gtm;
382 const u32 *clock;
383 int size;
384
385 gtm = kzalloc_obj(*gtm);
386 if (!gtm) {
387 pr_err("%pOF: unable to allocate memory\n",
388 np);
389 continue;
390 }
391
392 spin_lock_init(&gtm->lock);
393
394 clock = of_get_property(np, "clock-frequency", &size);
395 if (!clock || size != sizeof(*clock)) {
396 pr_err("%pOF: no clock-frequency\n", np);
397 goto err;
398 }
399 gtm->clock = *clock;
400
401 for (i = 0; i < ARRAY_SIZE(gtm->timers); i++) {
402 unsigned int irq;
403
404 irq = irq_of_parse_and_map(np, i);
405 if (!irq) {
406 pr_err("%pOF: not enough interrupts specified\n",
407 np);
408 goto err;
409 }
410 gtm->timers[i].irq = irq;
411 gtm->timers[i].gtm = gtm;
412 }
413
414 gtm->regs = of_iomap(np, 0);
415 if (!gtm->regs) {
416 pr_err("%pOF: unable to iomap registers\n",
417 np);
418 goto err;
419 }
420
421 gtm_set_shortcuts(np, gtm->timers, gtm->regs);
422 list_add(&gtm->list_node, &gtms);
423
424 /* We don't want to lose the node and its ->data */
425 np->data = gtm;
426 of_node_get(np);
427
428 continue;
429err:
430 kfree(gtm);
431 }
432 return 0;
433}
434arch_initcall(fsl_gtm_init);