bcm2835_tmr.c revision 1.9
1 /* $NetBSD: bcm2835_tmr.c,v 1.9 2017/12/10 21:38:26 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 1.9 2017/12/10 21:38:26 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/bcm2835_intr.h> 43 #include <arm/broadcom/bcm2835reg.h> 44 #include <arm/broadcom/bcm2835var.h> 45 46 #include <dev/fdt/fdtvar.h> 47 48 #include <arm/fdt/arm_fdtvar.h> 49 50 /* Use the 3rd timer*/ 51 #define BCMTIMER 3 52 53 #define BCM2835_STIMER_CS 0x00 54 #define BCM2835_STIMER_M0 __BIT(0) 55 #define BCM2835_STIMER_M1 __BIT(1) 56 #define BCM2835_STIMER_M2 __BIT(2) 57 #define BCM2835_STIMER_M3 __BIT(3) 58 #define BCM2835_STIMER_CLO 0x04 59 #define BCM2835_STIMER_CHI 0x08 60 #define BCM2835_STIMER_C0 0x0c 61 #define BCM2835_STIMER_C1 0x10 62 #define BCM2835_STIMER_C2 0x14 63 #define BCM2835_STIMER_C3 0x18 64 65 #define BCM2835_STIMER_HZ 1000000 66 67 static const uint32_t counts_per_usec = (BCM2835_STIMER_HZ / 1000000); 68 static uint32_t counts_per_hz = ~0; 69 70 struct bcm2835tmr_softc { 71 device_t sc_dev; 72 73 bus_space_tag_t sc_iot; 74 bus_space_handle_t sc_ioh; 75 76 void *sc_ih; 77 }; 78 79 static int bcmtmr_match(device_t, cfdata_t, void *); 80 static void bcmtmr_attach(device_t, device_t, void *); 81 82 static int clockhandler(void *); 83 84 static u_int bcm2835tmr_get_timecount(struct timecounter *); 85 void bcm2835_tmr_setstatclockrate(int); 86 87 static struct bcm2835tmr_softc *bcm2835tmr_sc; 88 89 static struct timecounter bcm2835tmr_timecounter = { 90 .tc_get_timecount = bcm2835tmr_get_timecount, 91 .tc_poll_pps = 0, 92 .tc_counter_mask = ~0u, 93 .tc_frequency = BCM2835_STIMER_HZ, 94 .tc_name = NULL, /* set by attach */ 95 .tc_quality = 100, 96 .tc_priv = NULL, 97 .tc_next = NULL, 98 }; 99 100 CFATTACH_DECL_NEW(bcmtmr_fdt, sizeof(struct bcm2835tmr_softc), 101 bcmtmr_match, bcmtmr_attach, NULL, NULL); 102 103 /* ARGSUSED */ 104 static int 105 bcmtmr_match(device_t parent, cfdata_t match, void *aux) 106 { 107 const char * const compatible[] = { 108 "brcm,bcm2835-system-timer", 109 NULL 110 }; 111 struct fdt_attach_args * const faa = aux; 112 return of_match_compatible(faa->faa_phandle, compatible); 113 } 114 115 static void 116 bcmtmr_attach(device_t parent, device_t self, void *aux) 117 { 118 struct bcm2835tmr_softc *sc = device_private(self); 119 struct fdt_attach_args * const faa = aux; 120 121 aprint_naive("\n"); 122 aprint_normal(": VC System Timer\n"); 123 124 if (bcm2835tmr_sc == NULL) 125 bcm2835tmr_sc = sc; 126 127 sc->sc_dev = self; 128 sc->sc_iot = faa->faa_bst; 129 const int phandle = faa->faa_phandle; 130 131 bus_addr_t addr; 132 bus_size_t size; 133 134 if (fdtbus_get_reg(phandle, 0, &addr, &size) != 0) { 135 aprint_error(": missing 'reg' property\n"); 136 return; 137 } 138 139 if (bus_space_map(sc->sc_iot, addr, size, 0, &sc->sc_ioh) != 0) { 140 aprint_error_dev(sc->sc_dev, "unable to map device\n"); 141 return; 142 } 143 144 char intrstr[128]; 145 if (!fdtbus_intr_str(phandle, BCMTIMER, intrstr, sizeof(intrstr))) { 146 aprint_error(": failed to decode interrupt\n"); 147 return; 148 } 149 150 sc->sc_ih = fdtbus_intr_establish(phandle, BCMTIMER, IPL_CLOCK, 151 FDT_INTR_MPSAFE, clockhandler, NULL); 152 if (sc->sc_ih == NULL) { 153 aprint_error(": failed to establish interrupt on %s\n", 154 intrstr); 155 return; 156 } 157 aprint_normal_dev(self, "interrupting on %s\n", intrstr); 158 159 bcm2835tmr_timecounter.tc_name = device_xname(self); 160 } 161 162 void 163 cpu_initclocks(void) 164 { 165 struct bcm2835tmr_softc *sc = bcm2835tmr_sc; 166 uint32_t stcl; 167 168 KASSERT(sc != NULL); 169 170 bcm2835tmr_timecounter.tc_priv = sc; 171 172 counts_per_hz = BCM2835_STIMER_HZ / hz; 173 174 stcl = bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CLO); 175 stcl += counts_per_hz; 176 177 bus_space_write_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_C3, stcl); 178 179 tc_init(&bcm2835tmr_timecounter); 180 } 181 182 void 183 bcm2835_tmr_delay(unsigned int n) 184 { 185 struct bcm2835tmr_softc *sc = bcm2835tmr_sc; 186 uint32_t last, curr; 187 uint32_t delta, usecs; 188 189 KASSERT(sc != NULL); 190 191 last = bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CLO); 192 193 delta = usecs = 0; 194 while (n > usecs) { 195 curr = bus_space_read_4(sc->sc_iot, sc->sc_ioh, 196 BCM2835_STIMER_CLO); 197 198 /* Check to see if the timer has wrapped around. */ 199 if (curr < last) 200 delta += curr + (UINT32_MAX - last); 201 else 202 delta += curr - last; 203 204 last = curr; 205 206 if (delta >= counts_per_usec) { 207 usecs += delta / counts_per_usec; 208 delta %= counts_per_usec; 209 } 210 } 211 212 } 213 214 /* 215 * clockhandler: 216 * 217 * Handle the hardclock interrupt. 218 */ 219 static int 220 clockhandler(void *arg) 221 { 222 struct bcm2835tmr_softc *sc = bcm2835tmr_sc; 223 struct clockframe *frame = arg; 224 uint32_t curr, status; 225 226 status = bus_space_read_4(sc->sc_iot, sc->sc_ioh, 227 BCM2835_STIMER_CS); 228 229 if (!(status & BCM2835_STIMER_M3)) 230 return 0; 231 232 bus_space_write_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CS, 233 BCM2835_STIMER_M3); 234 235 hardclock(frame); 236 237 curr = bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CLO); 238 239 curr += counts_per_hz; 240 bus_space_write_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_C3, curr); 241 242 return 1; 243 } 244 245 void 246 setstatclockrate(int newhz) 247 { 248 } 249 250 static u_int 251 bcm2835tmr_get_timecount(struct timecounter *tc) 252 { 253 struct bcm2835tmr_softc *sc = tc->tc_priv; 254 255 return bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CLO); 256 } 257 258
Indexes created Tue Sep 30 11:09:46 GMT 2025