1 /* $NetBSD: bcm2835_tmr.c,v 1.8 2017/09/21 19:28:14 skrll Exp $ */ 2 3 /*- 4 * Copyright (c) 2012 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Nick Hudson 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: bcm2835_tmr.c,v 1.8 2017/09/21 19:28:14 skrll Exp $"); 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/device.h> 38 #include <sys/kernel.h> 39 #include <sys/timetc.h> 40 #include <sys/bus.h> 41 42 #include <arm/broadcom/bcm_amba.h> 43 #include <arm/broadcom/bcm2835_intr.h> 44 #include <arm/broadcom/bcm2835reg.h> 45 46 #define BCM2835_STIMER_CS 0x00 47 #define BCM2835_STIMER_M0 __BIT(0) 48 #define BCM2835_STIMER_M1 __BIT(1) 49 #define BCM2835_STIMER_M2 __BIT(2) 50 #define BCM2835_STIMER_M3 __BIT(3) 51 #define BCM2835_STIMER_CLO 0x04 52 #define BCM2835_STIMER_CHI 0x08 53 #define BCM2835_STIMER_C0 0x0c 54 #define BCM2835_STIMER_C1 0x10 55 #define BCM2835_STIMER_C2 0x14 56 #define BCM2835_STIMER_C3 0x18 57 58 #define BCM2835_STIMER_HZ 1000000 59 60 static const uint32_t counts_per_usec = (BCM2835_STIMER_HZ / 1000000); 61 static uint32_t counts_per_hz = ~0; 62 63 struct bcm2835tmr_softc { 64 device_t sc_dev; 65 66 bus_space_tag_t sc_iot; 67 bus_space_handle_t sc_ioh; 68 }; 69 70 static int bcmtmr_match(device_t, cfdata_t, void *); 71 static void bcmtmr_attach(device_t, device_t, void *); 72 73 static int clockhandler(void *); 74 75 static u_int bcm2835tmr_get_timecount(struct timecounter *); 76 77 static struct bcm2835tmr_softc *bcm2835tmr_sc; 78 79 static struct timecounter bcm2835tmr_timecounter = { 80 .tc_get_timecount = bcm2835tmr_get_timecount, 81 .tc_poll_pps = 0, 82 .tc_counter_mask = ~0u, 83 .tc_frequency = BCM2835_STIMER_HZ, 84 .tc_name = NULL, /* set by attach */ 85 .tc_quality = 100, 86 .tc_priv = NULL, 87 .tc_next = NULL, 88 }; 89 90 CFATTACH_DECL_NEW(bcmtmr_amba, sizeof(struct bcm2835tmr_softc), 91 bcmtmr_match, bcmtmr_attach, NULL, NULL); 92 93 /* ARGSUSED */ 94 static int 95 bcmtmr_match(device_t parent, cfdata_t match, void *aux) 96 { 97 struct amba_attach_args *aaa = aux; 98 99 if (strcmp(aaa->aaa_name, "bcmtmr") != 0) 100 return 0; 101 102 return 1; 103 } 104 105 static void 106 bcmtmr_attach(device_t parent, device_t self, void *aux) 107 { 108 struct bcm2835tmr_softc *sc = device_private(self); 109 struct amba_attach_args *aaa = aux; 110 111 aprint_naive("\n"); 112 aprint_normal(": VC System Timer\n"); 113 114 if (bcm2835tmr_sc == NULL) 115 bcm2835tmr_sc = sc; 116 117 sc->sc_dev = self; 118 sc->sc_iot = aaa->aaa_iot; 119 120 if (bus_space_map(aaa->aaa_iot, aaa->aaa_addr, BCM2835_STIMER_SIZE, 0, 121 &sc->sc_ioh)) { 122 aprint_error_dev(sc->sc_dev, "unable to map device\n"); 123 return; 124 } 125 126 bcm2835tmr_timecounter.tc_name = device_xname(self); 127 } 128 129 void 130 cpu_initclocks(void) 131 { 132 struct bcm2835tmr_softc *sc = bcm2835tmr_sc; 133 void *clock_ih; 134 uint32_t stcl; 135 136 KASSERT(sc != NULL); 137 138 bcm2835tmr_timecounter.tc_priv = sc; 139 140 counts_per_hz = BCM2835_STIMER_HZ / hz; 141 142 stcl = bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CLO); 143 stcl += counts_per_hz; 144 145 bus_space_write_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_C3, stcl); 146 clock_ih = intr_establish(BCM2835_INT_TIMER3, IPL_CLOCK, IST_LEVEL, 147 clockhandler, NULL); 148 if (clock_ih == NULL) 149 panic("%s: unable to register timer interrupt", __func__); 150 151 tc_init(&bcm2835tmr_timecounter); 152 } 153 154 void 155 delay(unsigned int n) 156 { 157 struct bcm2835tmr_softc *sc = bcm2835tmr_sc; 158 uint32_t last, curr; 159 uint32_t delta, usecs; 160 161 KASSERT(sc != NULL); 162 163 last = bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CLO); 164 165 delta = usecs = 0; 166 while (n > usecs) { 167 curr = bus_space_read_4(sc->sc_iot, sc->sc_ioh, 168 BCM2835_STIMER_CLO); 169 170 /* Check to see if the timer has wrapped around. */ 171 if (curr < last) 172 delta += curr + (UINT32_MAX - last); 173 else 174 delta += curr - last; 175 176 last = curr; 177 178 if (delta >= counts_per_usec) { 179 usecs += delta / counts_per_usec; 180 delta %= counts_per_usec; 181 } 182 } 183 184 } 185 186 /* 187 * clockhandler: 188 * 189 * Handle the hardclock interrupt. 190 */ 191 static int 192 clockhandler(void *arg) 193 { 194 struct bcm2835tmr_softc *sc = bcm2835tmr_sc; 195 struct clockframe *frame = arg; 196 uint32_t curr, status; 197 198 status = bus_space_read_4(sc->sc_iot, sc->sc_ioh, 199 BCM2835_STIMER_CS); 200 201 if (!(status & BCM2835_STIMER_M3)) 202 return 0; 203 204 bus_space_write_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CS, 205 BCM2835_STIMER_M3); 206 207 hardclock(frame); 208 209 curr = bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CLO); 210 211 curr += counts_per_hz; 212 bus_space_write_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_C3, curr); 213 214 return 1; 215 } 216 217 void 218 setstatclockrate(int newhz) 219 { 220 } 221 222 static u_int 223 bcm2835tmr_get_timecount(struct timecounter *tc) 224 { 225 struct bcm2835tmr_softc *sc = tc->tc_priv; 226 227 return bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CLO); 228 } 229 230