1 /* $NetBSD: gtmr.c,v 1.3 2013/09/07 01:42:44 matt 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 Matt Thomas 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: gtmr.c,v 1.3 2013/09/07 01:42:44 matt Exp $"); 34 35 #include <sys/param.h> 36 #include <sys/bus.h> 37 #include <sys/device.h> 38 #include <sys/intr.h> 39 #include <sys/kernel.h> 40 #include <sys/proc.h> 41 #include <sys/systm.h> 42 #include <sys/timetc.h> 43 44 #include <prop/proplib.h> 45 46 #include <arm/cortex/gtmr_var.h> 47 48 #include <arm/cortex/mpcore_var.h> 49 50 static int gtmr_match(device_t, cfdata_t, void *); 51 static void gtmr_attach(device_t, device_t, void *); 52 53 static int clockhandler(void *); 54 55 static u_int gtmr_get_timecount(struct timecounter *); 56 57 static struct gtmr_softc gtmr_sc; 58 59 static struct timecounter gtmr_timecounter = { 60 .tc_get_timecount = gtmr_get_timecount, 61 .tc_poll_pps = 0, 62 .tc_counter_mask = ~0u, 63 .tc_frequency = 0, /* set by cpu_initclocks() */ 64 .tc_name = NULL, /* set by attach */ 65 .tc_quality = 500, 66 .tc_priv = >mr_sc, 67 .tc_next = NULL, 68 }; 69 70 CFATTACH_DECL_NEW(armgtmr, 0, gtmr_match, gtmr_attach, NULL, NULL); 71 72 /* ARGSUSED */ 73 static int 74 gtmr_match(device_t parent, cfdata_t cf, void *aux) 75 { 76 struct mpcore_attach_args * const mpcaa = aux; 77 78 if (gtmr_sc.sc_dev != NULL) 79 return 0; 80 81 if ((armreg_pfr1_read() & ARM_PFR1_GTIMER_MASK) == 0) 82 return 0; 83 84 if (strcmp(mpcaa->mpcaa_name, cf->cf_name) != 0) 85 return 0; 86 87 return 1; 88 } 89 90 static void 91 gtmr_attach(device_t parent, device_t self, void *aux) 92 { 93 struct gtmr_softc *sc = >mr_sc; 94 prop_dictionary_t dict = device_properties(self); 95 char freqbuf[sizeof("X.XXX SHz")]; 96 97 /* 98 * This runs at a fixed frequency of 1 to 50MHz. 99 */ 100 prop_dictionary_get_uint32(dict, "frequency", &sc->sc_freq); 101 102 humanize_number(freqbuf, sizeof(freqbuf), sc->sc_freq, "Hz", 1000); 103 104 aprint_naive("\n"); 105 aprint_normal(": ARMv7 Generic 64-bit Timer (%s)\n", freqbuf); 106 107 /* 108 * Enable the virtual counter to be accessed from usermode. 109 */ 110 armreg_cntk_ctl_write(armreg_cntk_ctl_read() | ARM_CNTKCTL_PL0VCTEN); 111 112 113 self->dv_private = sc; 114 sc->sc_dev = self; 115 116 evcnt_attach_dynamic(&sc->sc_ev_missing_ticks, EVCNT_TYPE_MISC, NULL, 117 device_xname(self), "missing interrupts"); 118 119 sc->sc_global_ih = intr_establish(IRQ_GTMR_PPI_VTIMER, IPL_CLOCK, 120 IST_EDGE, clockhandler, NULL); 121 if (sc->sc_global_ih == NULL) 122 panic("%s: unable to register timer interrupt", __func__); 123 aprint_normal_dev(sc->sc_dev, "interrupting on irq %d\n", 124 IRQ_GTMR_PPI_VTIMER); 125 } 126 127 void 128 gtmr_init_cpu_clock(struct cpu_info *ci) 129 { 130 struct gtmr_softc * const sc = >mr_sc; 131 132 KASSERT(ci == curcpu()); 133 134 int s = splsched(); 135 /* 136 * enable timer and stop masking the timer. 137 */ 138 armreg_cntv_ctl_write(ARM_CNTCTL_ENABLE); 139 140 /* 141 * Get now and update the compare timer. 142 */ 143 ci->ci_lastintr = armreg_cntv_ct_read(); 144 armreg_cntv_tval_write(sc->sc_autoinc); 145 #if 0 146 printf("%s: %s: delta cval = %"PRIu64"\n", 147 __func__, ci->ci_data.cpu_name, 148 armreg_cntv_cval_read() - ci->ci_lastintr); 149 #endif 150 splx(s); 151 #if 0 152 printf("%s: %s: ctl %#x cmp %#"PRIx64" now %#"PRIx64"\n", 153 __func__, ci->ci_data.cpu_name, armreg_cntv_ctl_read(), 154 armreg_cntv_cval_read(), armreg_cntv_ct_read()); 155 156 s = splsched(); 157 158 uint64_t now64; 159 uint64_t start64 = armreg_cntv_ct_read(); 160 do { 161 now64 = armreg_cntv_ct_read(); 162 } while (start64 == now64); 163 start64 = now64; 164 uint64_t end64 = start64 + 64; 165 uint32_t start32 = armreg_pmccntr_read(); 166 do { 167 now64 = armreg_cntv_ct_read(); 168 } while (end64 != now64); 169 uint32_t end32 = armreg_pmccntr_read(); 170 171 uint32_t diff32 = end64 - start64; 172 printf("%s: %s: %u cycles per tick\n", 173 __func__, ci->ci_data.cpu_name, (end32 - start32) / diff32); 174 175 printf("%s: %s: status %#x cmp %#"PRIx64" now %#"PRIx64"\n", 176 __func__, ci->ci_data.cpu_name, armreg_cntv_ctl_read(), 177 armreg_cntv_cval_read(), armreg_cntv_ct_read()); 178 splx(s); 179 #elif 0 180 delay(1000000 / hz + 1000); 181 #endif 182 } 183 184 void 185 cpu_initclocks(void) 186 { 187 struct gtmr_softc * const sc = >mr_sc; 188 189 KASSERT(sc->sc_dev != NULL); 190 KASSERT(sc->sc_freq != 0); 191 192 sc->sc_autoinc = sc->sc_freq / hz; 193 194 gtmr_init_cpu_clock(curcpu()); 195 196 gtmr_timecounter.tc_name = device_xname(sc->sc_dev); 197 gtmr_timecounter.tc_frequency = sc->sc_freq; 198 199 tc_init(>mr_timecounter); 200 } 201 202 void 203 gtmr_delay(unsigned int n) 204 { 205 struct gtmr_softc * const sc = >mr_sc; 206 207 KASSERT(sc != NULL); 208 209 uint32_t freq = sc->sc_freq ? sc->sc_freq : curcpu()->ci_data.cpu_cc_freq / 2; 210 KASSERT(freq != 0); 211 212 /* 213 * not quite divide by 1000000 but close enough 214 * (higher by 1.3% which means we wait 1.3% longer). 215 */ 216 const uint64_t incr_per_us = (freq >> 20) + (freq >> 24); 217 218 const uint64_t delta = n * incr_per_us; 219 const uint64_t base = armreg_cntv_ct_read(); 220 const uint64_t finish = base + delta; 221 222 while (armreg_cntv_ct_read() < finish) { 223 /* spin */ 224 } 225 } 226 227 /* 228 * clockhandler: 229 * 230 * Handle the hardclock interrupt. 231 */ 232 static int 233 clockhandler(void *arg) 234 { 235 struct clockframe * const cf = arg; 236 struct gtmr_softc * const sc = >mr_sc; 237 struct cpu_info * const ci = curcpu(); 238 239 const uint64_t now = armreg_cntv_ct_read(); 240 uint64_t delta = now - ci->ci_lastintr; 241 242 #ifdef DIAGNOSTIC 243 const uint64_t then = armreg_cntv_cval_read(); 244 KASSERTMSG(then <= now, "%"PRId64, now - then); 245 KASSERTMSG(then - ci->ci_lastintr >= sc->sc_autoinc, "%"PRId64, 246 then - ci->ci_lastintr - sc->sc_autoinc); 247 #endif 248 249 #if 0 250 printf("%s(%p): %s: now %#"PRIx64" delta %"PRIu64"\n", 251 __func__, cf, ci->ci_data.cpu_name, now, delta); 252 #endif 253 KASSERTMSG(delta > sc->sc_autoinc / 100, 254 "%s: interrupting too quickly (delta=%"PRIu64") autoinc=%lu", 255 ci->ci_data.cpu_name, delta, sc->sc_autoinc); 256 257 /* 258 * If we got interrutped too soon (delta < sc->sc_autoinc) or 259 * we missed a tick (delta >= 2 * sc->sc_autoinc), don't try to 260 * adjust for jitter. 261 */ 262 delta -= sc->sc_autoinc; 263 if (delta < 0 || delta >= sc->sc_autoinc) { 264 delta = 0; 265 } 266 armreg_cntv_tval_write(sc->sc_autoinc - delta); 267 268 ci->ci_lastintr = now - delta; 269 270 hardclock(cf); 271 272 if (delta > 2 * sc->sc_autoinc) 273 sc->sc_ev_missing_ticks.ev_count += (delta / sc->sc_autoinc) - 1; 274 275 return 1; 276 } 277 278 void 279 setstatclockrate(int newhz) 280 { 281 } 282 283 static u_int 284 gtmr_get_timecount(struct timecounter *tc) 285 { 286 287 return (u_int) (armreg_cntv_ct_read()); 288 } 289