1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2012 Damjan Marion <dmarion@Freebsd.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD: stable/12/sys/arm/ti/am335x/am335x_dmtimer.c 326258 2017-11-27 15:04:10Z pfg $");
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/bus.h>
35 #include <sys/kernel.h>
36 #include <sys/module.h>
37 #include <sys/malloc.h>
38 #include <sys/rman.h>
39 #include <sys/timeet.h>
40 #include <sys/timetc.h>
41 #include <machine/bus.h>
42
43 #include <machine/machdep.h> /* For arm_set_delay */
44
45 #include <dev/ofw/openfirm.h>
46 #include <dev/ofw/ofw_bus.h>
47 #include <dev/ofw/ofw_bus_subr.h>
48
49 #include <arm/ti/ti_prcm.h>
50 #include <arm/ti/ti_hwmods.h>
51
52 #include "am335x_dmtreg.h"
53
54 struct am335x_dmtimer_softc {
55 device_t dev;
56 int tmr_mem_rid;
57 struct resource * tmr_mem_res;
58 int tmr_irq_rid;
59 struct resource * tmr_irq_res;
60 void *tmr_irq_handler;
61 uint32_t sysclk_freq;
62 uint32_t tclr; /* Cached TCLR register. */
63 union {
64 struct timecounter tc;
65 struct eventtimer et;
66 } func;
67 int tmr_num; /* Hardware unit number. */
68 char tmr_name[12]; /* "DMTimerN", N = tmr_num */
69 };
70
71 static struct am335x_dmtimer_softc *am335x_dmtimer_et_sc = NULL;
72 static struct am335x_dmtimer_softc *am335x_dmtimer_tc_sc = NULL;
73
74 static void am335x_dmtimer_delay(int, void *);
75
76 /*
77 * We use dmtimer2 for eventtimer and dmtimer3 for timecounter.
78 */
79 #define ET_TMR_NUM 2
80 #define TC_TMR_NUM 3
81
82 /* List of compatible strings for FDT tree */
83 static struct ofw_compat_data compat_data[] = {
84 {"ti,am335x-timer", 1},
85 {"ti,am335x-timer-1ms", 1},
86 {NULL, 0},
87 };
88
89 #define DMTIMER_READ4(sc, reg) bus_read_4((sc)->tmr_mem_res, (reg))
90 #define DMTIMER_WRITE4(sc, reg, val) bus_write_4((sc)->tmr_mem_res, (reg), (val))
91
92 static int
am335x_dmtimer_et_start(struct eventtimer * et,sbintime_t first,sbintime_t period)93 am335x_dmtimer_et_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
94 {
95 struct am335x_dmtimer_softc *sc;
96 uint32_t initial_count, reload_count;
97
98 sc = et->et_priv;
99
100 /*
101 * Stop the timer before changing it. This routine will often be called
102 * while the timer is still running, to either lengthen or shorten the
103 * current event time. We need to ensure the timer doesn't expire while
104 * we're working with it.
105 *
106 * Also clear any pending interrupt status, because it's at least
107 * theoretically possible that we're running in a primary interrupt
108 * context now, and a timer interrupt could be pending even before we
109 * stopped the timer. The more likely case is that we're being called
110 * from the et_event_cb() routine dispatched from our own handler, but
111 * it's not clear to me that that's the only case possible.
112 */
113 sc->tclr &= ~(DMT_TCLR_START | DMT_TCLR_AUTOLOAD);
114 DMTIMER_WRITE4(sc, DMT_TCLR, sc->tclr);
115 DMTIMER_WRITE4(sc, DMT_IRQSTATUS, DMT_IRQ_OVF);
116
117 if (period != 0) {
118 reload_count = ((uint32_t)et->et_frequency * period) >> 32;
119 sc->tclr |= DMT_TCLR_AUTOLOAD;
120 } else {
121 reload_count = 0;
122 }
123
124 if (first != 0)
125 initial_count = ((uint32_t)et->et_frequency * first) >> 32;
126 else
127 initial_count = reload_count;
128
129 /*
130 * Set auto-reload and current-count values. This timer hardware counts
131 * up from the initial/reload value and interrupts on the zero rollover.
132 */
133 DMTIMER_WRITE4(sc, DMT_TLDR, 0xFFFFFFFF - reload_count);
134 DMTIMER_WRITE4(sc, DMT_TCRR, 0xFFFFFFFF - initial_count);
135
136 /* Enable overflow interrupt, and start the timer. */
137 DMTIMER_WRITE4(sc, DMT_IRQENABLE_SET, DMT_IRQ_OVF);
138 sc->tclr |= DMT_TCLR_START;
139 DMTIMER_WRITE4(sc, DMT_TCLR, sc->tclr);
140
141 return (0);
142 }
143
144 static int
am335x_dmtimer_et_stop(struct eventtimer * et)145 am335x_dmtimer_et_stop(struct eventtimer *et)
146 {
147 struct am335x_dmtimer_softc *sc;
148
149 sc = et->et_priv;
150
151 /* Stop timer, disable and clear interrupt. */
152 sc->tclr &= ~(DMT_TCLR_START | DMT_TCLR_AUTOLOAD);
153 DMTIMER_WRITE4(sc, DMT_TCLR, sc->tclr);
154 DMTIMER_WRITE4(sc, DMT_IRQENABLE_CLR, DMT_IRQ_OVF);
155 DMTIMER_WRITE4(sc, DMT_IRQSTATUS, DMT_IRQ_OVF);
156 return (0);
157 }
158
159 static int
am335x_dmtimer_et_intr(void * arg)160 am335x_dmtimer_et_intr(void *arg)
161 {
162 struct am335x_dmtimer_softc *sc;
163
164 sc = arg;
165
166 /* Ack the interrupt, and invoke the callback if it's still enabled. */
167 DMTIMER_WRITE4(sc, DMT_IRQSTATUS, DMT_IRQ_OVF);
168 if (sc->func.et.et_active)
169 sc->func.et.et_event_cb(&sc->func.et, sc->func.et.et_arg);
170
171 return (FILTER_HANDLED);
172 }
173
174 static int
am335x_dmtimer_et_init(struct am335x_dmtimer_softc * sc)175 am335x_dmtimer_et_init(struct am335x_dmtimer_softc *sc)
176 {
177 KASSERT(am335x_dmtimer_et_sc == NULL, ("already have an eventtimer"));
178
179 /*
180 * Setup eventtimer interrupt handling. Panic if anything goes wrong,
181 * because the system just isn't going to run without an eventtimer.
182 */
183 sc->tmr_irq_res = bus_alloc_resource_any(sc->dev, SYS_RES_IRQ,
184 &sc->tmr_irq_rid, RF_ACTIVE);
185 if (sc->tmr_irq_res == NULL)
186 panic("am335x_dmtimer: could not allocate irq resources");
187 if (bus_setup_intr(sc->dev, sc->tmr_irq_res, INTR_TYPE_CLK,
188 am335x_dmtimer_et_intr, NULL, sc, &sc->tmr_irq_handler) != 0)
189 panic("am335x_dmtimer: count not setup irq handler");
190
191 sc->func.et.et_name = sc->tmr_name;
192 sc->func.et.et_flags = ET_FLAGS_PERIODIC | ET_FLAGS_ONESHOT;
193 sc->func.et.et_quality = 500;
194 sc->func.et.et_frequency = sc->sysclk_freq;
195 sc->func.et.et_min_period =
196 ((0x00000005LLU << 32) / sc->func.et.et_frequency);
197 sc->func.et.et_max_period =
198 (0xfffffffeLLU << 32) / sc->func.et.et_frequency;
199 sc->func.et.et_start = am335x_dmtimer_et_start;
200 sc->func.et.et_stop = am335x_dmtimer_et_stop;
201 sc->func.et.et_priv = sc;
202
203 am335x_dmtimer_et_sc = sc;
204 et_register(&sc->func.et);
205
206 return (0);
207 }
208
209 static unsigned
am335x_dmtimer_tc_get_timecount(struct timecounter * tc)210 am335x_dmtimer_tc_get_timecount(struct timecounter *tc)
211 {
212 struct am335x_dmtimer_softc *sc;
213
214 sc = tc->tc_priv;
215
216 return (DMTIMER_READ4(sc, DMT_TCRR));
217 }
218
219 static int
am335x_dmtimer_tc_init(struct am335x_dmtimer_softc * sc)220 am335x_dmtimer_tc_init(struct am335x_dmtimer_softc *sc)
221 {
222 KASSERT(am335x_dmtimer_tc_sc == NULL, ("already have a timecounter"));
223
224 /* Set up timecounter, start it, register it. */
225 DMTIMER_WRITE4(sc, DMT_TSICR, DMT_TSICR_RESET);
226 while (DMTIMER_READ4(sc, DMT_TIOCP_CFG) & DMT_TIOCP_RESET)
227 continue;
228
229 sc->tclr |= DMT_TCLR_START | DMT_TCLR_AUTOLOAD;
230 DMTIMER_WRITE4(sc, DMT_TLDR, 0);
231 DMTIMER_WRITE4(sc, DMT_TCRR, 0);
232 DMTIMER_WRITE4(sc, DMT_TCLR, sc->tclr);
233
234 sc->func.tc.tc_name = sc->tmr_name;
235 sc->func.tc.tc_get_timecount = am335x_dmtimer_tc_get_timecount;
236 sc->func.tc.tc_counter_mask = ~0u;
237 sc->func.tc.tc_frequency = sc->sysclk_freq;
238 sc->func.tc.tc_quality = 500;
239 sc->func.tc.tc_priv = sc;
240
241 am335x_dmtimer_tc_sc = sc;
242 tc_init(&sc->func.tc);
243
244 arm_set_delay(am335x_dmtimer_delay, sc);
245
246 return (0);
247 }
248
249 static int
am335x_dmtimer_probe(device_t dev)250 am335x_dmtimer_probe(device_t dev)
251 {
252 char strbuf[32];
253 int tmr_num;
254
255 if (!ofw_bus_status_okay(dev))
256 return (ENXIO);
257
258 if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
259 return (ENXIO);
260
261 /*
262 * Get the hardware unit number (the N from ti,hwmods="timerN").
263 * If this isn't the hardware unit we're going to use for either the
264 * eventtimer or the timecounter, no point in instantiating the device.
265 */
266 tmr_num = ti_hwmods_get_unit(dev, "timer");
267 if (tmr_num != ET_TMR_NUM && tmr_num != TC_TMR_NUM)
268 return (ENXIO);
269
270 snprintf(strbuf, sizeof(strbuf), "AM335x DMTimer%d", tmr_num);
271 device_set_desc_copy(dev, strbuf);
272
273 return(BUS_PROBE_DEFAULT);
274 }
275
276 static int
am335x_dmtimer_attach(device_t dev)277 am335x_dmtimer_attach(device_t dev)
278 {
279 struct am335x_dmtimer_softc *sc;
280 clk_ident_t timer_id;
281 int err;
282
283 sc = device_get_softc(dev);
284 sc->dev = dev;
285
286 /* Get the base clock frequency. */
287 if ((err = ti_prcm_clk_get_source_freq(SYS_CLK, &sc->sysclk_freq)) != 0)
288 return (err);
289
290 /* Enable clocks and power on the device. */
291 if ((timer_id = ti_hwmods_get_clock(dev)) == INVALID_CLK_IDENT)
292 return (ENXIO);
293 if ((err = ti_prcm_clk_set_source(timer_id, SYSCLK_CLK)) != 0)
294 return (err);
295 if ((err = ti_prcm_clk_enable(timer_id)) != 0)
296 return (err);
297
298 /* Request the memory resources. */
299 sc->tmr_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY,
300 &sc->tmr_mem_rid, RF_ACTIVE);
301 if (sc->tmr_mem_res == NULL) {
302 return (ENXIO);
303 }
304
305 sc->tmr_num = ti_hwmods_get_unit(dev, "timer");
306 snprintf(sc->tmr_name, sizeof(sc->tmr_name), "DMTimer%d", sc->tmr_num);
307
308 /*
309 * Go set up either a timecounter or eventtimer. We wouldn't have
310 * attached if we weren't one or the other.
311 */
312 if (sc->tmr_num == ET_TMR_NUM)
313 am335x_dmtimer_et_init(sc);
314 else if (sc->tmr_num == TC_TMR_NUM)
315 am335x_dmtimer_tc_init(sc);
316 else
317 panic("am335x_dmtimer: bad timer number %d", sc->tmr_num);
318
319 return (0);
320 }
321
322 static device_method_t am335x_dmtimer_methods[] = {
323 DEVMETHOD(device_probe, am335x_dmtimer_probe),
324 DEVMETHOD(device_attach, am335x_dmtimer_attach),
325 { 0, 0 }
326 };
327
328 static driver_t am335x_dmtimer_driver = {
329 "am335x_dmtimer",
330 am335x_dmtimer_methods,
331 sizeof(struct am335x_dmtimer_softc),
332 };
333
334 static devclass_t am335x_dmtimer_devclass;
335
336 DRIVER_MODULE(am335x_dmtimer, simplebus, am335x_dmtimer_driver, am335x_dmtimer_devclass, 0, 0);
337 MODULE_DEPEND(am335x_dmtimer, am335x_prcm, 1, 1, 1);
338
339 static void
am335x_dmtimer_delay(int usec,void * arg)340 am335x_dmtimer_delay(int usec, void *arg)
341 {
342 struct am335x_dmtimer_softc *sc = arg;
343 int32_t counts;
344 uint32_t first, last;
345
346 /* Get the number of times to count */
347 counts = (usec + 1) * (sc->sysclk_freq / 1000000);
348
349 first = DMTIMER_READ4(sc, DMT_TCRR);
350
351 while (counts > 0) {
352 last = DMTIMER_READ4(sc, DMT_TCRR);
353 if (last > first) {
354 counts -= (int32_t)(last - first);
355 } else {
356 counts -= (int32_t)((0xFFFFFFFF - first) + last);
357 }
358 first = last;
359 }
360 }
361