/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2012, 2013 The FreeBSD Foundation * * This software was developed by Oleksandr Rybalko under sponsorship * from the FreeBSD Foundation. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include #include #include #include #include #include #include #include #include #include #include /* For arm_set_delay */ #include #include #include #include #include #define WRITE4(_sc, _r, _v) \ bus_space_write_4((_sc)->sc_iot, (_sc)->sc_ioh, (_r), (_v)) #define READ4(_sc, _r) \ bus_space_read_4((_sc)->sc_iot, (_sc)->sc_ioh, (_r)) #define SET4(_sc, _r, _m) \ WRITE4((_sc), (_r), READ4((_sc), (_r)) | (_m)) #define CLEAR4(_sc, _r, _m) \ WRITE4((_sc), (_r), READ4((_sc), (_r)) & ~(_m)) static u_int imx_gpt_get_timecount(struct timecounter *); static int imx_gpt_timer_start(struct eventtimer *, sbintime_t, sbintime_t); static int imx_gpt_timer_stop(struct eventtimer *); static void imx_gpt_do_delay(int, void *); static int imx_gpt_intr(void *); static int imx_gpt_probe(device_t); static int imx_gpt_attach(device_t); static struct timecounter imx_gpt_timecounter = { .tc_name = "iMXGPT", .tc_get_timecount = imx_gpt_get_timecount, .tc_counter_mask = ~0u, .tc_frequency = 0, .tc_quality = 1000, }; struct imx_gpt_softc { device_t sc_dev; struct resource * res[2]; bus_space_tag_t sc_iot; bus_space_handle_t sc_ioh; void * sc_ih; /* interrupt handler */ uint32_t sc_period; uint32_t sc_clksrc; uint32_t clkfreq; uint32_t ir_reg; struct eventtimer et; }; /* Try to divide down an available fast clock to this frequency. */ #define TARGET_FREQUENCY 1000000000 static struct resource_spec imx_gpt_spec[] = { { SYS_RES_MEMORY, 0, RF_ACTIVE }, { SYS_RES_IRQ, 0, RF_ACTIVE }, { -1, 0 } }; static struct ofw_compat_data compat_data[] = { {"fsl,imx6dl-gpt", 1}, {"fsl,imx6q-gpt", 1}, {"fsl,imx6ul-gpt", 1}, {"fsl,imx53-gpt", 1}, {"fsl,imx51-gpt", 1}, {"fsl,imx31-gpt", 1}, {"fsl,imx27-gpt", 1}, {"fsl,imx25-gpt", 1}, {NULL, 0} }; static int imx_gpt_probe(device_t dev) { if (!ofw_bus_status_okay(dev)) return (ENXIO); /* * We only support a single unit, because the only thing this driver * does with the complex timer hardware is supply the system * timecounter and eventtimer. There is nothing useful we can do with * the additional device instances that exist in some chips. */ if (device_get_unit(dev) > 0) return (ENXIO); if (ofw_bus_search_compatible(dev, compat_data)->ocd_data != 0) { device_set_desc(dev, "Freescale i.MX GPT timer"); return (BUS_PROBE_DEFAULT); } return (ENXIO); } static int imx_gpt_attach(device_t dev) { struct imx_gpt_softc *sc; int ctlreg, err; uint32_t basefreq, prescale, setup_ticks, t1, t2; sc = device_get_softc(dev); if (bus_alloc_resources(dev, imx_gpt_spec, sc->res)) { device_printf(dev, "could not allocate resources\n"); return (ENXIO); } sc->sc_dev = dev; sc->sc_iot = rman_get_bustag(sc->res[0]); sc->sc_ioh = rman_get_bushandle(sc->res[0]); /* * For now, just automatically choose a good clock for the hardware * we're running on. Eventually we could allow selection from the fdt; * the code in this driver will cope with any clock frequency. */ sc->sc_clksrc = GPT_CR_CLKSRC_IPG; ctlreg = 0; switch (sc->sc_clksrc) { case GPT_CR_CLKSRC_32K: basefreq = 32768; break; case GPT_CR_CLKSRC_IPG: basefreq = imx_ccm_ipg_hz(); break; case GPT_CR_CLKSRC_IPG_HIGH: basefreq = imx_ccm_ipg_hz() * 2; break; case GPT_CR_CLKSRC_24M: ctlreg |= GPT_CR_24MEN; basefreq = 24000000; break; case GPT_CR_CLKSRC_NONE:/* Can't run without a clock. */ case GPT_CR_CLKSRC_EXT: /* No way to get the freq of an ext clock. */ default: device_printf(dev, "Unsupported clock source '%d'\n", sc->sc_clksrc); return (EINVAL); } /* * The following setup sequence is from the I.MX6 reference manual, * "Selecting the clock source". First, disable the clock and * interrupts. This also clears input and output mode bits and in * general completes several of the early steps in the procedure. */ WRITE4(sc, IMX_GPT_CR, 0); WRITE4(sc, IMX_GPT_IR, 0); /* Choose the clock and the power-saving behaviors. */ ctlreg |= sc->sc_clksrc | /* Use selected clock */ GPT_CR_FRR | /* Just count (FreeRunner mode) */ GPT_CR_STOPEN | /* Run in STOP mode */ GPT_CR_DOZEEN | /* Run in DOZE mode */ GPT_CR_WAITEN | /* Run in WAIT mode */ GPT_CR_DBGEN; /* Run in DEBUG mode */ WRITE4(sc, IMX_GPT_CR, ctlreg); /* * The datasheet says to do the software reset after choosing the clock * source. It says nothing about needing to wait for the reset to * complete, but the register description does document the fact that * the reset isn't complete until the SWR bit reads 0, so let's be safe. * The reset also clears all registers except for a few of the bits in * CR, but we'll rewrite all the CR bits when we start the counter. */ WRITE4(sc, IMX_GPT_CR, ctlreg | GPT_CR_SWR); while (READ4(sc, IMX_GPT_CR) & GPT_CR_SWR) continue; /* Set a prescaler value that gets us near the target frequency. */ if (basefreq < TARGET_FREQUENCY) { prescale = 0; sc->clkfreq = basefreq; } else { prescale = basefreq / TARGET_FREQUENCY; sc->clkfreq = basefreq / prescale; prescale -= 1; /* 1..n range is 0..n-1 in hardware. */ } WRITE4(sc, IMX_GPT_PR, prescale); /* Clear the status register. */ WRITE4(sc, IMX_GPT_SR, GPT_IR_ALL); /* Start the counter. */ WRITE4(sc, IMX_GPT_CR, ctlreg | GPT_CR_EN); if (bootverbose) device_printf(dev, "Running on %dKHz clock, base freq %uHz CR=0x%08x, PR=0x%08x\n", sc->clkfreq / 1000, basefreq, READ4(sc, IMX_GPT_CR), READ4(sc, IMX_GPT_PR)); /* Setup the timer interrupt. */ err = bus_setup_intr(dev, sc->res[1], INTR_TYPE_CLK, imx_gpt_intr, NULL, sc, &sc->sc_ih); if (err != 0) { bus_release_resources(dev, imx_gpt_spec, sc->res); device_printf(dev, "Unable to setup the clock irq handler, " "err = %d\n", err); return (ENXIO); } /* * Measure how many clock ticks it takes to setup a one-shot event (it's * longer than you might think, due to wait states in accessing gpt * registers). Scale up the result by a factor of 1.5 to be safe, * and use that to set the minimum eventtimer period we can schedule. In * the real world, the value works out to about 750ns on imx5 hardware. */ t1 = READ4(sc, IMX_GPT_CNT); WRITE4(sc, IMX_GPT_OCR3, 0); t2 = READ4(sc, IMX_GPT_CNT); setup_ticks = ((t2 - t1 + 1) * 3) / 2; /* Register as an eventtimer. */ sc->et.et_name = "iMXGPT"; sc->et.et_flags = ET_FLAGS_ONESHOT | ET_FLAGS_PERIODIC; sc->et.et_quality = 800; sc->et.et_frequency = sc->clkfreq; sc->et.et_min_period = ((uint64_t)setup_ticks << 32) / sc->clkfreq; sc->et.et_max_period = ((uint64_t)0xfffffffe << 32) / sc->clkfreq; sc->et.et_start = imx_gpt_timer_start; sc->et.et_stop = imx_gpt_timer_stop; sc->et.et_priv = sc; et_register(&sc->et); /* Register as a timecounter. */ imx_gpt_timecounter.tc_frequency = sc->clkfreq; imx_gpt_timecounter.tc_priv = sc; tc_init(&imx_gpt_timecounter); /* If this is the first unit, store the softc for use in DELAY. */ if (device_get_unit(dev) == 0) { arm_set_delay(imx_gpt_do_delay, sc); } return (0); } static int imx_gpt_timer_start(struct eventtimer *et, sbintime_t first, sbintime_t period) { struct imx_gpt_softc *sc; uint32_t ticks; sc = (struct imx_gpt_softc *)et->et_priv; if (period != 0) { sc->sc_period = ((uint32_t)et->et_frequency * period) >> 32; /* Set expected value */ WRITE4(sc, IMX_GPT_OCR2, READ4(sc, IMX_GPT_CNT) + sc->sc_period); /* Enable compare register 2 Interrupt */ sc->ir_reg |= GPT_IR_OF2; WRITE4(sc, IMX_GPT_IR, sc->ir_reg); return (0); } else if (first != 0) { /* Enable compare register 3 interrupt if not already on. */ if ((sc->ir_reg & GPT_IR_OF3) == 0) { sc->ir_reg |= GPT_IR_OF3; WRITE4(sc, IMX_GPT_IR, sc->ir_reg); } ticks = ((uint32_t)et->et_frequency * first) >> 32; /* Do not disturb, otherwise event will be lost */ spinlock_enter(); /* Set expected value */ WRITE4(sc, IMX_GPT_OCR3, READ4(sc, IMX_GPT_CNT) + ticks); /* Now everybody can relax */ spinlock_exit(); return (0); } return (EINVAL); } static int imx_gpt_timer_stop(struct eventtimer *et) { struct imx_gpt_softc *sc; sc = (struct imx_gpt_softc *)et->et_priv; /* Disable interrupts and clear any pending status. */ sc->ir_reg &= ~(GPT_IR_OF2 | GPT_IR_OF3); WRITE4(sc, IMX_GPT_IR, sc->ir_reg); WRITE4(sc, IMX_GPT_SR, GPT_IR_OF2 | GPT_IR_OF3); sc->sc_period = 0; return (0); } static int imx_gpt_intr(void *arg) { struct imx_gpt_softc *sc; uint32_t status; sc = (struct imx_gpt_softc *)arg; status = READ4(sc, IMX_GPT_SR); /* * Clear interrupt status before invoking event callbacks. The callback * often sets up a new one-shot timer event and if the interval is short * enough it can fire before we get out of this function. If we cleared * at the bottom we'd miss the interrupt and hang until the clock wraps. */ WRITE4(sc, IMX_GPT_SR, status); /* Handle one-shot timer events. */ if (status & GPT_IR_OF3) { if (sc->et.et_active) { sc->et.et_event_cb(&sc->et, sc->et.et_arg); } } /* Handle periodic timer events. */ if (status & GPT_IR_OF2) { if (sc->et.et_active) sc->et.et_event_cb(&sc->et, sc->et.et_arg); if (sc->sc_period != 0) WRITE4(sc, IMX_GPT_OCR2, READ4(sc, IMX_GPT_CNT) + sc->sc_period); } return (FILTER_HANDLED); } static u_int imx_gpt_get_timecount(struct timecounter *tc) { struct imx_gpt_softc *sc; sc = tc->tc_priv; return (READ4(sc, IMX_GPT_CNT)); } static device_method_t imx_gpt_methods[] = { DEVMETHOD(device_probe, imx_gpt_probe), DEVMETHOD(device_attach, imx_gpt_attach), DEVMETHOD_END }; static driver_t imx_gpt_driver = { "imx_gpt", imx_gpt_methods, sizeof(struct imx_gpt_softc), }; EARLY_DRIVER_MODULE(imx_gpt, simplebus, imx_gpt_driver, 0, 0, BUS_PASS_TIMER); static void imx_gpt_do_delay(int usec, void *arg) { struct imx_gpt_softc *sc = arg; uint64_t curcnt, endcnt, startcnt, ticks; /* * Calculate the tick count with 64-bit values so that it works for any * clock frequency. Loop until the hardware count reaches start+ticks. * If the 32-bit hardware count rolls over while we're looping, just * manually do a carry into the high bits after each read; don't worry * that doing this on each loop iteration is inefficient -- we're trying * to waste time here. */ ticks = 1 + ((uint64_t)usec * sc->clkfreq) / 1000000; curcnt = startcnt = READ4(sc, IMX_GPT_CNT); endcnt = startcnt + ticks; while (curcnt < endcnt) { curcnt = READ4(sc, IMX_GPT_CNT); if (curcnt < startcnt) curcnt += 1ULL << 32; } }