at91_pit.c revision 330897
1/*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2009 Gallon Sylvestre. All rights reserved. 5 * Copyright (c) 2010 Greg Ansley. 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 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 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 "opt_platform.h" 30 31#include <sys/cdefs.h> 32__FBSDID("$FreeBSD: stable/11/sys/arm/at91/at91_pit.c 330897 2018-03-14 03:19:51Z eadler $"); 33 34#include <sys/param.h> 35#include <sys/bus.h> 36#include <sys/kernel.h> 37#include <sys/module.h> 38#include <sys/resource.h> 39#include <sys/systm.h> 40#include <sys/rman.h> 41#include <sys/time.h> 42#include <sys/timetc.h> 43#include <sys/watchdog.h> 44 45#include <machine/bus.h> 46#include <machine/cpu.h> 47#include <machine/frame.h> 48#include <machine/intr.h> 49#include <machine/resource.h> 50 51#include <arm/at91/at91var.h> 52#include <arm/at91/at91_pitreg.h> 53 54#ifdef FDT 55#include <dev/fdt/fdt_common.h> 56#include <dev/ofw/ofw_bus.h> 57#include <dev/ofw/ofw_bus_subr.h> 58#endif 59 60#ifndef PIT_PRESCALE 61#define PIT_PRESCALE (16) 62#endif 63 64static struct pit_softc { 65 struct resource *mem_res; /* Memory resource */ 66 void *intrhand; /* Interrupt handle */ 67 device_t sc_dev; 68} *sc; 69 70static uint32_t timecount = 0; 71static unsigned at91_pit_get_timecount(struct timecounter *tc); 72static int pit_intr(void *arg); 73 74static inline uint32_t 75RD4(struct pit_softc *sc, bus_size_t off) 76{ 77 78 return (bus_read_4(sc->mem_res, off)); 79} 80 81static inline void 82WR4(struct pit_softc *sc, bus_size_t off, uint32_t val) 83{ 84 85 bus_write_4(sc->mem_res, off, val); 86} 87 88void 89at91_pit_delay(int us) 90{ 91 int32_t cnt, last, piv; 92 uint64_t pit_freq; 93 const uint64_t mhz = 1E6; 94 95 if (sc == NULL) 96 return; 97 98 last = PIT_PIV(RD4(sc, PIT_PIIR)); 99 100 /* Max delay ~= 260s. @ 133Mhz */ 101 pit_freq = at91_master_clock / PIT_PRESCALE; 102 cnt = howmany(pit_freq * us, mhz); 103 cnt = (cnt <= 0) ? 1 : cnt; 104 105 while (cnt > 0) { 106 piv = PIT_PIV(RD4(sc, PIT_PIIR)); 107 cnt -= piv - last ; 108 if (piv < last) 109 cnt -= PIT_PIV(~0u) - last; 110 last = piv; 111 } 112} 113 114static struct timecounter at91_pit_timecounter = { 115 at91_pit_get_timecount, /* get_timecount */ 116 NULL, /* no poll_pps */ 117 0xffffffff, /* counter mask */ 118 0 / PIT_PRESCALE, /* frequency */ 119 "AT91SAM9 timer", /* name */ 120 1000 /* quality */ 121}; 122 123static int 124at91_pit_probe(device_t dev) 125{ 126#ifdef FDT 127 if (!ofw_bus_is_compatible(dev, "atmel,at91sam9260-pit")) 128 return (ENXIO); 129#endif 130 device_set_desc(dev, "AT91SAM9 PIT"); 131 return (0); 132} 133 134static int 135at91_pit_attach(device_t dev) 136{ 137 void *ih; 138 int rid, err = 0; 139 struct resource *irq; 140 141 sc = device_get_softc(dev); 142 sc->sc_dev = dev; 143 144 rid = 0; 145 sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, 146 RF_ACTIVE); 147 148 if (sc->mem_res == NULL) 149 panic("couldn't allocate register resources"); 150 151 rid = 0; 152 irq = bus_alloc_resource(dev, SYS_RES_IRQ, &rid, 1, 1, 1, 153 RF_ACTIVE | RF_SHAREABLE); 154 if (!irq) { 155 device_printf(dev, "could not allocate interrupt resources.\n"); 156 err = ENOMEM; 157 goto out; 158 } 159 160 /* Activate the interrupt. */ 161 err = bus_setup_intr(dev, irq, INTR_TYPE_CLK, pit_intr, NULL, NULL, 162 &ih); 163 164 at91_pit_timecounter.tc_frequency = at91_master_clock / PIT_PRESCALE; 165 tc_init(&at91_pit_timecounter); 166 167 /* Enable the PIT here. */ 168 WR4(sc, PIT_MR, PIT_PIV(at91_master_clock / PIT_PRESCALE / hz) | 169 PIT_EN | PIT_IEN); 170out: 171 return (err); 172} 173 174 175static int 176pit_intr(void *arg) 177{ 178 struct trapframe *fp = arg; 179 uint32_t icnt; 180 181 if (RD4(sc, PIT_SR) & PIT_PITS_DONE) { 182 icnt = RD4(sc, PIT_PIVR) >> 20; 183 184 /* Just add in the overflows we just read */ 185 timecount += PIT_PIV(RD4(sc, PIT_MR)) * icnt; 186 187 hardclock(TRAPF_USERMODE(fp), TRAPF_PC(fp)); 188 return (FILTER_HANDLED); 189 } 190 return (FILTER_STRAY); 191} 192 193static unsigned 194at91_pit_get_timecount(struct timecounter *tc) 195{ 196 uint32_t piir, icnt; 197 198 piir = RD4(sc, PIT_PIIR); /* Current count | over flows */ 199 icnt = piir >> 20; /* Overflows */ 200 return (timecount + PIT_PIV(piir) + PIT_PIV(RD4(sc, PIT_MR)) * icnt); 201} 202 203static device_method_t at91_pit_methods[] = { 204 DEVMETHOD(device_probe, at91_pit_probe), 205 DEVMETHOD(device_attach, at91_pit_attach), 206 DEVMETHOD_END 207}; 208 209static driver_t at91_pit_driver = { 210 "at91_pit", 211 at91_pit_methods, 212 sizeof(struct pit_softc), 213}; 214 215static devclass_t at91_pit_devclass; 216 217#ifdef FDT 218EARLY_DRIVER_MODULE(at91_pit, simplebus, at91_pit_driver, at91_pit_devclass, 219 NULL, NULL, BUS_PASS_TIMER); 220#else 221EARLY_DRIVER_MODULE(at91_pit, atmelarm, at91_pit_driver, at91_pit_devclass, 222 NULL, NULL, BUS_PASS_TIMER); 223#endif 224