Author: ian
Date: Sun Jun 18 18:22:52 2017
New Revision: 320076
URL: https://svnweb.freebsd.org/changeset/base/320076
Log:
Add a driver for the imx6 EPIT timer that can be used as the system
timecounter instead of the GPT timer, freeing up the more flexible GPT
hardware for other uses. The EPIT driver is a standard (always in the
kernel) driver, and the existing GPT driver is now optional and included
only if you ask for device imx_gpt.
Added:
head/sys/arm/freescale/imx/imx_epit.c (contents, props changed)
Modified:
head/sys/arm/freescale/imx/files.imx6
head/sys/arm/freescale/imx/imx6_ccm.c
head/sys/arm/freescale/imx/imx6_ccmreg.h
Modified: head/sys/arm/freescale/imx/files.imx6
==============================================================================
--- head/sys/arm/freescale/imx/files.imx6 Sun Jun 18 18:09:31 2017
(r320075)
+++ head/sys/arm/freescale/imx/files.imx6 Sun Jun 18 18:22:52 2017
(r320076)
@@ -15,9 +15,10 @@ arm/freescale/imx/imx6_machdep.c standard
arm/freescale/imx/imx6_mp.c optional smp
arm/freescale/imx/imx6_pl310.c standard
arm/freescale/imx/imx6_src.c standard
+arm/freescale/imx/imx_epit.c standard
arm/freescale/imx/imx_iomux.c standard
arm/freescale/imx/imx_machdep.c standard
-arm/freescale/imx/imx_gpt.c standard
+arm/freescale/imx/imx_gpt.c optional imx_gpt
arm/freescale/imx/imx_gpio.c optional gpio
arm/freescale/imx/imx_i2c.c optional fsliic
arm/freescale/imx/imx6_sdma.c optional sdma
Modified: head/sys/arm/freescale/imx/imx6_ccm.c
==============================================================================
--- head/sys/arm/freescale/imx/imx6_ccm.c Sun Jun 18 18:09:31 2017
(r320075)
+++ head/sys/arm/freescale/imx/imx6_ccm.c Sun Jun 18 18:22:52 2017
(r320076)
@@ -94,8 +94,8 @@ ccm_init_gates(struct ccm_softc *sc)
reg = CCGR0_AIPS_TZ1 | CCGR0_AIPS_TZ2 | CCGR0_ABPHDMA;
WR4(sc, CCM_CCGR0, reg);
- /* gpt, enet */
- reg = CCGR1_ENET | CCGR1_GPT;
+ /* enet, epit, gpt */
+ reg = CCGR1_ENET | CCGR1_EPIT1 | CCGR1_GPT;
WR4(sc, CCM_CCGR1, reg);
/* ipmux & ipsync (bridges), iomux, i2c */
Modified: head/sys/arm/freescale/imx/imx6_ccmreg.h
==============================================================================
--- head/sys/arm/freescale/imx/imx6_ccmreg.h Sun Jun 18 18:09:31 2017
(r320075)
+++ head/sys/arm/freescale/imx/imx6_ccmreg.h Sun Jun 18 18:22:52 2017
(r320076)
@@ -79,7 +79,10 @@
#define CCGR0_ABPHDMA (0x3 << 4)
#define CCM_CCGR1 0x06C
#define CCGR1_ENET (0x3 << 10)
+#define CCGR1_EPIT1 (0x3 << 12)
+#define CCGR1_EPIT2 (0x3 << 14)
#define CCGR1_GPT (0x3 << 20)
+#define CCGR1_GPT_SERIAL (0x3 << 22)
#define CCM_CCGR2 0x070
#define CCGR2_HDMI_TX (0x3 << 0)
#define CCGR2_HDMI_TX_ISFR (0x3 << 4)
Added: head/sys/arm/freescale/imx/imx_epit.c
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ head/sys/arm/freescale/imx/imx_epit.c Sun Jun 18 18:22:52 2017
(r320076)
@@ -0,0 +1,528 @@
+/*-
+ * Copyright (c) 2017 Ian Lepore <[email protected]>
+ * All rights reserved.
+ *
+ * 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 <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+/*
+ * Driver for imx Enhanced Programmable Interval Timer, a simple free-running
+ * counter device that can be used as the system timecounter. On imx5 a second
+ * instance of the device is used as the system eventtimer.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+#include <sys/malloc.h>
+#include <sys/rman.h>
+#include <sys/timeet.h>
+#include <sys/timetc.h>
+#include <sys/watchdog.h>
+#include <machine/bus.h>
+#include <machine/cpu.h>
+#include <machine/intr.h>
+#include <machine/machdep.h>
+
+#include <dev/fdt/fdt_common.h>
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/ofw_bus.h>
+#include <dev/ofw/ofw_bus_subr.h>
+
+#include <arm/freescale/imx/imx_ccmvar.h>
+#include <arm/freescale/imx/imx_machdep.h>
+
+#define EPIT_CR 0x00 /* Control
register */
+#define EPIT_CR_CLKSRC_SHIFT 24
+#define EPIT_CR_CLKSRC_OFF 0
+#define EPIT_CR_CLKSRC_IPG 1
+#define EPIT_CR_CLKSRC_HFCLK 2
+#define EPIT_CR_CLKSRC_LFCLK 3
+#define EPIT_CR_STOPEN (1u << 21)
+#define EPIT_CR_WAITEN (1u << 19)
+#define EPIT_CR_DBGEN (1u << 18)
+#define EPIT_CR_IOVW (1u << 17)
+#define EPIT_CR_SWR (1u << 16)
+#define EPIT_CR_RLD (1u << 3)
+#define EPIT_CR_OCIEN (1u << 2)
+#define EPIT_CR_ENMOD (1u << 1)
+#define EPIT_CR_EN (1u << 0)
+
+#define EPIT_SR 0x04 /* Status
register */
+#define EPIT_SR_OCIF (1u << 0)
+
+#define EPIT_LR 0x08 /* Load
register */
+#define EPIT_CMPR 0x0c /* Compare
register */
+#define EPIT_CNR 0x10 /* Counter
register */
+
+/*
+ * Define event timer limits.
+ *
+ * In theory our minimum period is 1 tick, because to setup a oneshot we don't
+ * need a read-modify-write sequence to calculate and set a compare register
+ * value while the counter is running. In practice the waveform diagrams in
the
+ * manual make it appear that a setting of 1 might cause it to miss the event,
+ * so I'm setting the lower limit to 2 ticks.
+ */
+#define ET_MIN_TICKS 2
+#define ET_MAX_TICKS 0xfffffffe
+
+static u_int epit_tc_get_timecount(struct timecounter *tc);
+
+struct epit_softc {
+ device_t dev;
+ struct resource * memres;
+ struct resource * intres;
+ void * inthandle;
+ uint32_t clkfreq;
+ uint32_t ctlreg;
+ uint32_t period;
+ struct timecounter tc;
+ struct eventtimer et;
+ bool oneshot;
+};
+
+#ifndef MULTIDELAY
+/* Global softc pointer for use in DELAY(). */
+static struct epit_softc *epit_sc;
+#endif
+
+/*
+ * Probe data. For some reason, the standard linux dts files don't have
+ * compatible properties on the epit devices (other properties are missing too,
+ * like clocks, but we don't care as much about that). So our probe routine
+ * uses the name of the node (must contain "epit") and the address of the
+ * registers as identifying marks.
+ */
+static const uint32_t imx51_epit_ioaddr[2] = {0x73fac000, 0x73fb0000};
+static const uint32_t imx53_epit_ioaddr[2] = {0x53fac000, 0x53fb0000};
+static const uint32_t imx6_epit_ioaddr[2] = {0x020d0000, 0x020d4000};
+
+/* ocd_data is number of units to instantiate on the platform */
+static struct ofw_compat_data compat_data[] = {
+ {"fsl,imx6ul-epit", 1},
+ {"fsl,imx6sx-epit", 1},
+ {"fsl,imx6q-epit", 1},
+ {"fsl,imx6dl-epit", 1},
+ {"fsl,imx53-epit", 2},
+ {"fsl,imx51-epit", 2},
+ {"fsl,imx31-epit", 2},
+ {"fsl,imx27-epit", 2},
+ {"fsl,imx25-epit", 2},
+ {NULL, 0}
+};
+
+static inline uint32_t
+RD4(struct epit_softc *sc, bus_size_t offset)
+{
+
+ return (bus_read_4(sc->memres, offset));
+}
+
+static inline void
+WR4(struct epit_softc *sc, bus_size_t offset, uint32_t value)
+{
+
+ bus_write_4(sc->memres, offset, value);
+}
+
+static inline void
+WR4B(struct epit_softc *sc, bus_size_t offset, uint32_t value)
+{
+
+ bus_write_4(sc->memres, offset, value);
+ bus_barrier(sc->memres, offset, 4, BUS_SPACE_BARRIER_WRITE);
+}
+
+static u_int
+epit_read_counter(struct epit_softc *sc)
+{
+
+ /*
+ * Hardware is a downcounter, adjust to look like it counts up for use
+ * with timecounter and DELAY.
+ */
+ return (0xffffffff - RD4(sc, EPIT_CNR));
+}
+
+static void
+epit_do_delay(int usec, void *arg)
+{
+ struct epit_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 = epit_read_counter(sc);
+ endcnt = startcnt + ticks;
+ while (curcnt < endcnt) {
+ curcnt = epit_read_counter(sc);
+ if (curcnt < startcnt)
+ curcnt += 1ULL << 32;
+ }
+}
+
+static u_int
+epit_tc_get_timecount(struct timecounter *tc)
+{
+
+ return (epit_read_counter(tc->tc_priv));
+}
+
+static int
+epit_tc_attach(struct epit_softc *sc)
+{
+
+ /* When the counter hits zero, reload with 0xffffffff. Start it. */
+ WR4(sc, EPIT_LR, 0xffffffff);
+ WR4(sc, EPIT_CR, sc->ctlreg | EPIT_CR_EN);
+
+ /* Register as a timecounter. */
+ sc->tc.tc_name = "EPIT";
+ sc->tc.tc_quality = 1000;
+ sc->tc.tc_frequency = sc->clkfreq;
+ sc->tc.tc_counter_mask = 0xffffffff;
+ sc->tc.tc_get_timecount = epit_tc_get_timecount;
+ sc->tc.tc_priv = sc;
+ tc_init(&sc->tc);
+
+ /* We are the DELAY() implementation. */
+#ifdef MULTIDELAY
+ arm_set_delay(epit_do_delay, sc);
+#else
+ epit_sc = sc;
+#endif
+ return (0);
+}
+
+static int
+epit_et_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
+{
+ struct epit_softc *sc;
+ uint32_t ticks;
+
+ sc = (struct epit_softc *)et->et_priv;
+
+ /*
+ * Disable the timer and clear any pending status. The timer may be
+ * running or may have just expired if we're called to reschedule the
+ * next event before the previous event time arrives.
+ */
+ WR4(sc, EPIT_CR, sc->ctlreg);
+ WR4(sc, EPIT_SR, EPIT_SR_OCIF);
+ if (period != 0) {
+ sc->oneshot = false;
+ ticks = ((uint32_t)et->et_frequency * period) >> 32;
+ } else if (first != 0) {
+ sc->oneshot = true;
+ ticks = ((uint32_t)et->et_frequency * first) >> 32;
+ } else {
+ return (EINVAL);
+ }
+
+ /* Set the countdown load register and start the timer. */
+ WR4(sc, EPIT_LR, ticks);
+ WR4B(sc, EPIT_CR, sc->ctlreg | EPIT_CR_EN);
+
+ return (0);
+}
+
+static int
+epit_et_stop(struct eventtimer *et)
+{
+ struct epit_softc *sc;
+
+ sc = (struct epit_softc *)et->et_priv;
+
+ /* Disable the timer and clear any pending status. */
+ WR4(sc, EPIT_CR, sc->ctlreg);
+ WR4B(sc, EPIT_SR, EPIT_SR_OCIF);
+
+ return (0);
+}
+
+static int
+epit_intr(void *arg)
+{
+ struct epit_softc *sc;
+ uint32_t status;
+
+ sc = arg;
+
+ /*
+ * Disable a one-shot timer until a new event is scheduled so that the
+ * counter doesn't wrap and fire again. Do this before clearing the
+ * status since a short period would make it fire again really soon.
+ *
+ * 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.
+ */
+ if (sc->oneshot)
+ WR4(sc, EPIT_CR, sc->ctlreg);
+
+ status = RD4(sc, EPIT_SR);
+ WR4B(sc, EPIT_SR, status);
+
+ if ((status & EPIT_SR_OCIF) == 0)
+ return (FILTER_STRAY);
+
+ if (sc->et.et_active)
+ sc->et.et_event_cb(&sc->et, sc->et.et_arg);
+
+ return (FILTER_HANDLED);
+}
+
+static int
+epit_et_attach(struct epit_softc *sc)
+{
+ int err, rid;
+
+ rid = 0;
+ sc->intres = bus_alloc_resource_any(sc->dev, SYS_RES_IRQ, &rid,
+ RF_ACTIVE);
+ if (sc->intres == NULL) {
+ device_printf(sc->dev, "could not allocate interrupt\n");
+ return (ENXIO);
+ }
+
+ err = bus_setup_intr(sc->dev, sc->intres, INTR_TYPE_CLK | INTR_MPSAFE,
+ epit_intr, NULL, sc, &sc->inthandle);
+ if (err != 0) {
+ device_printf(sc->dev, "unable to setup the irq handler\n");
+ return (err);
+ }
+
+ /* To be an eventtimer, we need interrupts enabled. */
+ sc->ctlreg |= EPIT_CR_OCIEN;
+
+ /* Register as an eventtimer. */
+ sc->et.et_name = "EPIT";
+ sc->et.et_flags = ET_FLAGS_ONESHOT | ET_FLAGS_PERIODIC;
+ sc->et.et_quality = 1000;
+ sc->et.et_frequency = sc->clkfreq;
+ sc->et.et_min_period = ((uint64_t)ET_MIN_TICKS << 32) / sc->clkfreq;
+ sc->et.et_max_period = ((uint64_t)ET_MAX_TICKS << 32) / sc->clkfreq;
+ sc->et.et_start = epit_et_start;
+ sc->et.et_stop = epit_et_stop;
+ sc->et.et_priv = sc;
+ et_register(&sc->et);
+
+ return (0);
+}
+
+static int
+epit_probe(device_t dev)
+{
+ struct resource *memres;
+ rman_res_t ioaddr;
+ int num_units, rid, unit;
+
+ if (!ofw_bus_status_okay(dev))
+ return (ENXIO);
+
+ /*
+ * The FDT data for imx5 and imx6 EPIT hardware is missing or broken,
+ * but it may get fixed some day, so first just do a normal check. We
+ * return success if the compatible string matches and we haven't
+ * already instantiated the number of units needed on this platform.
+ */
+ unit = device_get_unit(dev);
+ num_units = ofw_bus_search_compatible(dev, compat_data)->ocd_data;
+ if (unit < num_units) {
+ device_set_desc(dev, "i.MX EPIT timer");
+ return (BUS_PROBE_DEFAULT);
+ }
+
+ /*
+ * No compat string match, but for imx6 all the data we need is in the
+ * node except the compat string, so do our own compatibility check
+ * using the device name of the node and the register block address.
+ */
+ if (strstr(ofw_bus_get_name(dev), "epit") == NULL)
+ return (ENXIO);
+
+ rid = 0;
+ memres = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_UNMAPPED);
+ if (memres == NULL)
+ return (ENXIO);
+ ioaddr = rman_get_start(memres);
+ bus_free_resource(dev, SYS_RES_MEMORY, memres);
+
+ if (imx_soc_family() == 6) {
+ if (unit > 0)
+ return (ENXIO);
+ if (ioaddr != imx6_epit_ioaddr[unit])
+ return (ENXIO);
+ } else {
+ if (unit > 1)
+ return (ENXIO);
+ switch (imx_soc_type()) {
+ case IMXSOC_51:
+ if (ioaddr != imx51_epit_ioaddr[unit])
+ return (ENXIO);
+ break;
+ case IMXSOC_53:
+ if (ioaddr != imx53_epit_ioaddr[unit])
+ return (ENXIO);
+ break;
+ default:
+ return (ENXIO);
+ }
+ /*
+ * XXX Right now we have no way to handle the fact that the
+ * entire EPIT node is missing, which means no interrupt data.
+ */
+ return (ENXIO);
+ }
+
+ device_set_desc(dev, "i.MX EPIT timer");
+ return (BUS_PROBE_DEFAULT);
+}
+
+static int
+epit_attach(device_t dev)
+{
+ struct epit_softc *sc;
+ int err, rid;
+ uint32_t clksrc;
+
+ sc = device_get_softc(dev);
+ sc->dev = dev;
+
+ rid = 0;
+ sc->memres = bus_alloc_resource_any(sc->dev, SYS_RES_MEMORY, &rid,
+ RF_ACTIVE);
+ if (sc->memres == NULL) {
+ device_printf(sc->dev, "could not allocate registers\n");
+ return (ENXIO);
+ }
+
+ /*
+ * For now, use ipg (66 MHz). Some day we should get this from fdt.
+ */
+ clksrc = EPIT_CR_CLKSRC_IPG;
+
+ switch (clksrc) {
+ default:
+ device_printf(dev,
+ "Unsupported clock source '%d', using IPG\n", clksrc);
+ /* FALLTHROUGH */
+ case EPIT_CR_CLKSRC_IPG:
+ sc->clkfreq = imx_ccm_ipg_hz();
+ break;
+ case EPIT_CR_CLKSRC_HFCLK:
+ sc->clkfreq = imx_ccm_perclk_hz();
+ break;
+ case EPIT_CR_CLKSRC_LFCLK:
+ sc->clkfreq = 32768;
+ break;
+ }
+
+ /*
+ * Init: stop operations and clear all options, then set up options and
+ * clock source, then do a soft-reset and wait for it to complete.
+ */
+ WR4(sc, EPIT_CR, 0);
+
+ sc->ctlreg =
+ (clksrc << EPIT_CR_CLKSRC_SHIFT) | /* Use selected clock */
+ EPIT_CR_ENMOD | /* Reload counter on enable */
+ EPIT_CR_RLD | /* Reload counter from LR */
+ EPIT_CR_STOPEN | /* Run in STOP mode */
+ EPIT_CR_WAITEN | /* Run in WAIT mode */
+ EPIT_CR_DBGEN; /* Run in DEBUG mode */
+
+ WR4B(sc, EPIT_CR, sc->ctlreg | EPIT_CR_SWR);
+ while (RD4(sc, EPIT_CR) & EPIT_CR_SWR)
+ continue;
+
+ /*
+ * Unit 0 is the timecounter, 1 (if instantiated) is the eventtimer.
+ */
+ if (device_get_unit(sc->dev) == 0)
+ err = epit_tc_attach(sc);
+ else
+ err = epit_et_attach(sc);
+
+ return (err);
+}
+
+static device_method_t epit_methods[] = {
+ DEVMETHOD(device_probe, epit_probe),
+ DEVMETHOD(device_attach, epit_attach),
+
+ DEVMETHOD_END
+};
+
+static driver_t epit_driver = {
+ "imx_epit",
+ epit_methods,
+ sizeof(struct epit_softc),
+};
+
+static devclass_t epit_devclass;
+
+EARLY_DRIVER_MODULE(imx_epit, simplebus, epit_driver, epit_devclass, 0,
+ 0, BUS_PASS_TIMER);
+
+#ifndef MULTIDELAY
+
+/*
+ * Hand-calibrated delay-loop counter. This was calibrated on an i.MX6 running
+ * at 792mhz. It will delay a bit too long on slower processors -- that's
+ * better than not delaying long enough. In practice this is unlikely to get
+ * used much since the clock driver is one of the first to start up, and once
+ * we're attached the delay loop switches to using the timer hardware.
+ */
+static const int epit_delay_count = 78;
+
+void
+DELAY(int usec)
+{
+ uint64_t ticks;
+
+ /* If the timer hardware is not accessible, just use a loop. */
+ if (epit_sc == NULL) {
+ while (usec-- > 0)
+ for (ticks = 0; ticks < epit_delay_count; ++ticks)
+ cpufunc_nullop();
+ return;
+ } else {
+ epit_do_delay(usec, epit_sc);
+ }
+}
+
+#endif
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