at91_pit.c revision 331722
1/*- 2 * Copyright (c) 2009 Gallon Sylvestre. All rights reserved. 3 * Copyright (c) 2010 Greg Ansley. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include "opt_platform.h" 28 29#include <sys/cdefs.h> 30__FBSDID("$FreeBSD: stable/11/sys/arm/at91/at91_pit.c 331722 2018-03-29 02:50:57Z eadler $"); 31 32#include <sys/param.h> 33#include <sys/bus.h> 34#include <sys/kernel.h> 35#include <sys/module.h> 36#include <sys/resource.h> 37#include <sys/systm.h> 38#include <sys/rman.h> 39#include <sys/time.h> 40#include <sys/timetc.h> 41#include <sys/watchdog.h> 42 43#include <machine/bus.h> 44#include <machine/cpu.h> 45#include <machine/frame.h> 46#include <machine/intr.h> 47#include <machine/resource.h> 48 49#include <arm/at91/at91var.h> 50#include <arm/at91/at91_pitreg.h> 51 52#ifdef FDT 53#include <dev/fdt/fdt_common.h> 54#include <dev/ofw/ofw_bus.h> 55#include <dev/ofw/ofw_bus_subr.h> 56#endif 57 58#ifndef PIT_PRESCALE 59#define PIT_PRESCALE (16) 60#endif 61 62static struct pit_softc { 63 struct resource *mem_res; /* Memory resource */ 64 void *intrhand; /* Interrupt handle */ 65 device_t sc_dev; 66} *sc; 67 68static uint32_t timecount = 0; 69static unsigned at91_pit_get_timecount(struct timecounter *tc); 70static int pit_intr(void *arg); 71 72static inline uint32_t 73RD4(struct pit_softc *sc, bus_size_t off) 74{ 75 76 return (bus_read_4(sc->mem_res, off)); 77} 78 79static inline void 80WR4(struct pit_softc *sc, bus_size_t off, uint32_t val) 81{ 82 83 bus_write_4(sc->mem_res, off, val); 84} 85 86void 87at91_pit_delay(int us) 88{ 89 int32_t cnt, last, piv; 90 uint64_t pit_freq; 91 const uint64_t mhz = 1E6; 92 93 if (sc == NULL) 94 return; 95 96 last = PIT_PIV(RD4(sc, PIT_PIIR)); 97 98 /* Max delay ~= 260s. @ 133Mhz */ 99 pit_freq = at91_master_clock / PIT_PRESCALE; 100 cnt = howmany(pit_freq * us, mhz); 101 cnt = (cnt <= 0) ? 1 : cnt; 102 103 while (cnt > 0) { 104 piv = PIT_PIV(RD4(sc, PIT_PIIR)); 105 cnt -= piv - last ; 106 if (piv < last) 107 cnt -= PIT_PIV(~0u) - last; 108 last = piv; 109 } 110} 111 112static struct timecounter at91_pit_timecounter = { 113 at91_pit_get_timecount, /* get_timecount */ 114 NULL, /* no poll_pps */ 115 0xffffffff, /* counter mask */ 116 0 / PIT_PRESCALE, /* frequency */ 117 "AT91SAM9 timer", /* name */ 118 1000 /* quality */ 119}; 120 121static int 122at91_pit_probe(device_t dev) 123{ 124#ifdef FDT 125 if (!ofw_bus_is_compatible(dev, "atmel,at91sam9260-pit")) 126 return (ENXIO); 127#endif 128 device_set_desc(dev, "AT91SAM9 PIT"); 129 return (0); 130} 131 132static int 133at91_pit_attach(device_t dev) 134{ 135 void *ih; 136 int rid, err = 0; 137 struct resource *irq; 138 139 sc = device_get_softc(dev); 140 sc->sc_dev = dev; 141 142 rid = 0; 143 sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, 144 RF_ACTIVE); 145 146 if (sc->mem_res == NULL) 147 panic("couldn't allocate register resources"); 148 149 rid = 0; 150 irq = bus_alloc_resource(dev, SYS_RES_IRQ, &rid, 1, 1, 1, 151 RF_ACTIVE | RF_SHAREABLE); 152 if (!irq) { 153 device_printf(dev, "could not allocate interrupt resources.\n"); 154 err = ENOMEM; 155 goto out; 156 } 157 158 /* Activate the interrupt. */ 159 err = bus_setup_intr(dev, irq, INTR_TYPE_CLK, pit_intr, NULL, NULL, 160 &ih); 161 162 at91_pit_timecounter.tc_frequency = at91_master_clock / PIT_PRESCALE; 163 tc_init(&at91_pit_timecounter); 164 165 /* Enable the PIT here. */ 166 WR4(sc, PIT_MR, PIT_PIV(at91_master_clock / PIT_PRESCALE / hz) | 167 PIT_EN | PIT_IEN); 168out: 169 return (err); 170} 171 172 173static int 174pit_intr(void *arg) 175{ 176 struct trapframe *fp = arg; 177 uint32_t icnt; 178 179 if (RD4(sc, PIT_SR) & PIT_PITS_DONE) { 180 icnt = RD4(sc, PIT_PIVR) >> 20; 181 182 /* Just add in the overflows we just read */ 183 timecount += PIT_PIV(RD4(sc, PIT_MR)) * icnt; 184 185 hardclock(TRAPF_USERMODE(fp), TRAPF_PC(fp)); 186 return (FILTER_HANDLED); 187 } 188 return (FILTER_STRAY); 189} 190 191static unsigned 192at91_pit_get_timecount(struct timecounter *tc) 193{ 194 uint32_t piir, icnt; 195 196 piir = RD4(sc, PIT_PIIR); /* Current count | over flows */ 197 icnt = piir >> 20; /* Overflows */ 198 return (timecount + PIT_PIV(piir) + PIT_PIV(RD4(sc, PIT_MR)) * icnt); 199} 200 201static device_method_t at91_pit_methods[] = { 202 DEVMETHOD(device_probe, at91_pit_probe), 203 DEVMETHOD(device_attach, at91_pit_attach), 204 DEVMETHOD_END 205}; 206 207static driver_t at91_pit_driver = { 208 "at91_pit", 209 at91_pit_methods, 210 sizeof(struct pit_softc), 211}; 212 213static devclass_t at91_pit_devclass; 214 215#ifdef FDT 216EARLY_DRIVER_MODULE(at91_pit, simplebus, at91_pit_driver, at91_pit_devclass, 217 NULL, NULL, BUS_PASS_TIMER); 218#else 219EARLY_DRIVER_MODULE(at91_pit, atmelarm, at91_pit_driver, at91_pit_devclass, 220 NULL, NULL, BUS_PASS_TIMER); 221#endif 222