2 * Copyright (c) 2012, 2013 The FreeBSD Foundation
5 * This software was developed by Oleksandr Rybalko under sponsorship
6 * from the FreeBSD Foundation.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
33 #include <sys/param.h>
34 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 #include <sys/module.h>
38 #include <sys/malloc.h>
40 #include <sys/timeet.h>
41 #include <sys/timetc.h>
42 #include <sys/watchdog.h>
43 #include <machine/bus.h>
44 #include <machine/cpu.h>
45 #include <machine/intr.h>
47 #include <machine/fdt.h>
48 #include <dev/fdt/fdt_common.h>
49 #include <dev/ofw/openfirm.h>
50 #include <dev/ofw/ofw_bus.h>
51 #include <dev/ofw/ofw_bus_subr.h>
53 #include <arm/freescale/imx/imx_gptvar.h>
54 #include <arm/freescale/imx/imx_gptreg.h>
57 #include <arm/freescale/imx/imx_ccmvar.h>
59 #define WRITE4(_sc, _r, _v) \
60 bus_space_write_4((_sc)->sc_iot, (_sc)->sc_ioh, (_r), (_v))
61 #define READ4(_sc, _r) \
62 bus_space_read_4((_sc)->sc_iot, (_sc)->sc_ioh, (_r))
63 #define SET4(_sc, _r, _m) \
64 WRITE4((_sc), (_r), READ4((_sc), (_r)) | (_m))
65 #define CLEAR4(_sc, _r, _m) \
66 WRITE4((_sc), (_r), READ4((_sc), (_r)) & ~(_m))
68 static u_int imx_gpt_get_timecount(struct timecounter *);
69 static int imx_gpt_timer_start(struct eventtimer *, sbintime_t,
71 static int imx_gpt_timer_stop(struct eventtimer *);
73 static int imx_gpt_intr(void *);
74 static int imx_gpt_probe(device_t);
75 static int imx_gpt_attach(device_t);
77 static struct timecounter imx_gpt_timecounter = {
79 .tc_get_timecount = imx_gpt_get_timecount,
80 .tc_counter_mask = ~0u,
85 /* Global softc pointer for use in DELAY(). */
86 struct imx_gpt_softc *imx_gpt_sc = NULL;
89 * Hand-calibrated delay-loop counter. This was calibrated on an i.MX6 running
90 * at 792mhz. It will delay a bit too long on slower processors -- that's
91 * better than not delaying long enough. In practice this is unlikely to get
92 * used much since the clock driver is one of the first to start up, and once
93 * we're attached the delay loop switches to using the timer hardware.
95 static const int imx_gpt_delay_count = 78;
97 /* Try to divide down an available fast clock to this frequency. */
98 #define TARGET_FREQUENCY 1000000000
100 /* Don't try to set an event timer period smaller than this. */
101 #define MIN_ET_PERIOD 10LLU
104 static struct resource_spec imx_gpt_spec[] = {
105 { SYS_RES_MEMORY, 0, RF_ACTIVE },
106 { SYS_RES_IRQ, 0, RF_ACTIVE },
110 static struct ofw_compat_data compat_data[] = {
111 {"fsl,imx6q-gpt", 1},
112 {"fsl,imx53-gpt", 1},
113 {"fsl,imx51-gpt", 1},
114 {"fsl,imx31-gpt", 1},
115 {"fsl,imx27-gpt", 1},
116 {"fsl,imx25-gpt", 1},
121 imx_gpt_probe(device_t dev)
124 if (!ofw_bus_status_okay(dev))
127 if (ofw_bus_search_compatible(dev, compat_data)->ocd_data != 0) {
128 device_set_desc(dev, "Freescale i.MX GPT timer");
129 return (BUS_PROBE_DEFAULT);
136 imx_gpt_attach(device_t dev)
138 struct imx_gpt_softc *sc;
140 uint32_t basefreq, prescale;
142 sc = device_get_softc(dev);
144 if (bus_alloc_resources(dev, imx_gpt_spec, sc->res)) {
145 device_printf(dev, "could not allocate resources\n");
150 sc->sc_iot = rman_get_bustag(sc->res[0]);
151 sc->sc_ioh = rman_get_bushandle(sc->res[0]);
154 * For now, just automatically choose a good clock for the hardware
155 * we're running on. Eventually we could allow selection from the fdt;
156 * the code in this driver will cope with any clock frequency.
158 sc->sc_clksrc = GPT_CR_CLKSRC_IPG;
162 switch (sc->sc_clksrc) {
163 case GPT_CR_CLKSRC_32K:
166 case GPT_CR_CLKSRC_IPG:
167 basefreq = imx_ccm_ipg_hz();
169 case GPT_CR_CLKSRC_IPG_HIGH:
170 basefreq = imx_ccm_ipg_hz() * 2;
172 case GPT_CR_CLKSRC_24M:
173 ctlreg |= GPT_CR_24MEN;
176 case GPT_CR_CLKSRC_NONE:/* Can't run without a clock. */
177 case GPT_CR_CLKSRC_EXT: /* No way to get the freq of an ext clock. */
179 device_printf(dev, "Unsupported clock source '%d'\n",
185 * The following setup sequence is from the I.MX6 reference manual,
186 * "Selecting the clock source". First, disable the clock and
187 * interrupts. This also clears input and output mode bits and in
188 * general completes several of the early steps in the procedure.
190 WRITE4(sc, IMX_GPT_CR, 0);
191 WRITE4(sc, IMX_GPT_IR, 0);
193 /* Choose the clock and the power-saving behaviors. */
195 sc->sc_clksrc | /* Use selected clock */
196 GPT_CR_FRR | /* Just count (FreeRunner mode) */
197 GPT_CR_STOPEN | /* Run in STOP mode */
198 GPT_CR_DOZEEN | /* Run in DOZE mode */
199 GPT_CR_WAITEN | /* Run in WAIT mode */
200 GPT_CR_DBGEN; /* Run in DEBUG mode */
201 WRITE4(sc, IMX_GPT_CR, ctlreg);
204 * The datasheet says to do the software reset after choosing the clock
205 * source. It says nothing about needing to wait for the reset to
206 * complete, but the register description does document the fact that
207 * the reset isn't complete until the SWR bit reads 0, so let's be safe.
208 * The reset also clears all registers except for a few of the bits in
209 * CR, but we'll rewrite all the CR bits when we start the counter.
211 WRITE4(sc, IMX_GPT_CR, ctlreg | GPT_CR_SWR);
212 while (READ4(sc, IMX_GPT_CR) & GPT_CR_SWR)
215 /* Set a prescaler value that gets us near the target frequency. */
216 if (basefreq < TARGET_FREQUENCY) {
218 sc->clkfreq = basefreq;
220 prescale = basefreq / TARGET_FREQUENCY;
221 sc->clkfreq = basefreq / prescale;
222 prescale -= 1; /* 1..n range is 0..n-1 in hardware. */
224 WRITE4(sc, IMX_GPT_PR, prescale);
226 /* Clear the status register. */
227 WRITE4(sc, IMX_GPT_SR, GPT_IR_ALL);
229 /* Start the counter. */
230 WRITE4(sc, IMX_GPT_CR, ctlreg | GPT_CR_EN);
233 device_printf(dev, "Running on %dKHz clock, base freq %uHz CR=0x%08x, PR=0x%08x\n",
234 sc->clkfreq / 1000, basefreq, READ4(sc, IMX_GPT_CR), READ4(sc, IMX_GPT_PR));
236 /* Setup the timer interrupt. */
237 err = bus_setup_intr(dev, sc->res[1], INTR_TYPE_CLK, imx_gpt_intr,
238 NULL, sc, &sc->sc_ih);
240 bus_release_resources(dev, imx_gpt_spec, sc->res);
241 device_printf(dev, "Unable to setup the clock irq handler, "
246 /* Register as an eventtimer. */
247 sc->et.et_name = "iMXGPT";
248 sc->et.et_flags = ET_FLAGS_ONESHOT | ET_FLAGS_PERIODIC;
249 sc->et.et_quality = 800;
250 sc->et.et_frequency = sc->clkfreq;
251 sc->et.et_min_period = (MIN_ET_PERIOD << 32) / sc->et.et_frequency;
252 sc->et.et_max_period = (0xfffffffeLLU << 32) / sc->et.et_frequency;
253 sc->et.et_start = imx_gpt_timer_start;
254 sc->et.et_stop = imx_gpt_timer_stop;
256 et_register(&sc->et);
258 /* Register as a timecounter. */
259 imx_gpt_timecounter.tc_frequency = sc->clkfreq;
260 tc_init(&imx_gpt_timecounter);
262 /* If this is the first unit, store the softc for use in DELAY. */
263 if (device_get_unit(dev) == 0)
270 imx_gpt_timer_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
272 struct imx_gpt_softc *sc;
275 sc = (struct imx_gpt_softc *)et->et_priv;
278 sc->sc_period = ((uint32_t)et->et_frequency * period) >> 32;
279 /* Set expected value */
280 WRITE4(sc, IMX_GPT_OCR2, READ4(sc, IMX_GPT_CNT) + sc->sc_period);
281 /* Enable compare register 2 Interrupt */
282 SET4(sc, IMX_GPT_IR, GPT_IR_OF2);
284 } else if (first != 0) {
285 ticks = ((uint32_t)et->et_frequency * first) >> 32;
286 /* Do not disturb, otherwise event will be lost */
288 /* Set expected value */
289 WRITE4(sc, IMX_GPT_OCR3, READ4(sc, IMX_GPT_CNT) + ticks);
290 /* Enable compare register 1 Interrupt */
291 SET4(sc, IMX_GPT_IR, GPT_IR_OF3);
292 /* Now everybody can relax */
301 imx_gpt_timer_stop(struct eventtimer *et)
303 struct imx_gpt_softc *sc;
305 sc = (struct imx_gpt_softc *)et->et_priv;
307 /* Disable OF2 Interrupt */
308 CLEAR4(sc, IMX_GPT_IR, GPT_IR_OF2);
309 WRITE4(sc, IMX_GPT_SR, GPT_IR_OF2);
316 imx_gpt_get_timerfreq(struct imx_gpt_softc *sc)
319 return (sc->clkfreq);
323 imx_gpt_intr(void *arg)
325 struct imx_gpt_softc *sc;
328 sc = (struct imx_gpt_softc *)arg;
330 status = READ4(sc, IMX_GPT_SR);
333 * Clear interrupt status before invoking event callbacks. The callback
334 * often sets up a new one-shot timer event and if the interval is short
335 * enough it can fire before we get out of this function. If we cleared
336 * at the bottom we'd miss the interrupt and hang until the clock wraps.
338 WRITE4(sc, IMX_GPT_SR, status);
340 /* Handle one-shot timer events. */
341 if (status & GPT_IR_OF3) {
342 if (sc->et.et_active) {
343 sc->et.et_event_cb(&sc->et, sc->et.et_arg);
347 /* Handle periodic timer events. */
348 if (status & GPT_IR_OF2) {
349 if (sc->et.et_active)
350 sc->et.et_event_cb(&sc->et, sc->et.et_arg);
351 if (sc->sc_period != 0)
352 WRITE4(sc, IMX_GPT_OCR2, READ4(sc, IMX_GPT_CNT) +
356 return (FILTER_HANDLED);
360 imx_gpt_get_timecount(struct timecounter *tc)
363 if (imx_gpt_sc == NULL)
366 return (READ4(imx_gpt_sc, IMX_GPT_CNT));
369 static device_method_t imx_gpt_methods[] = {
370 DEVMETHOD(device_probe, imx_gpt_probe),
371 DEVMETHOD(device_attach, imx_gpt_attach),
376 static driver_t imx_gpt_driver = {
379 sizeof(struct imx_gpt_softc),
382 static devclass_t imx_gpt_devclass;
384 EARLY_DRIVER_MODULE(imx_gpt, simplebus, imx_gpt_driver, imx_gpt_devclass, 0,
390 uint64_t curcnt, endcnt, startcnt, ticks;
392 /* If the timer hardware is not accessible, just use a loop. */
393 if (imx_gpt_sc == NULL) {
395 for (ticks = 0; ticks < imx_gpt_delay_count; ++ticks)
401 * Calculate the tick count with 64-bit values so that it works for any
402 * clock frequency. Loop until the hardware count reaches start+ticks.
403 * If the 32-bit hardware count rolls over while we're looping, just
404 * manually do a carry into the high bits after each read; don't worry
405 * that doing this on each loop iteration is inefficient -- we're trying
406 * to waste time here.
408 ticks = 1 + ((uint64_t)usec * imx_gpt_sc->clkfreq) / 1000000;
409 curcnt = startcnt = READ4(imx_gpt_sc, IMX_GPT_CNT);
410 endcnt = startcnt + ticks;
411 while (curcnt < endcnt) {
412 curcnt = READ4(imx_gpt_sc, IMX_GPT_CNT);
413 if (curcnt < startcnt)
414 curcnt += 1ULL << 32;