1 /*- 2 * Copyright (c) 2015-2024 Ruslan Bukin <br@bsdpad.com> 3 * All rights reserved. 4 * 5 * Portions of this software were developed by SRI International and the 6 * University of Cambridge Computer Laboratory under DARPA/AFRL contract 7 * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme. 8 * 9 * Portions of this software were developed by the University of Cambridge 10 * Computer Laboratory as part of the CTSRD Project, with support from the 11 * UK Higher Education Innovation Fund (HEIF). 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 /* 36 * RISC-V Timer 37 */ 38 39 #include "opt_platform.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/bus.h> 44 #include <sys/intr.h> 45 #include <sys/kernel.h> 46 #include <sys/module.h> 47 #include <sys/rman.h> 48 #include <sys/timeet.h> 49 #include <sys/timetc.h> 50 #include <sys/vdso.h> 51 #include <sys/watchdog.h> 52 53 #include <machine/cpufunc.h> 54 #include <machine/md_var.h> 55 #include <machine/sbi.h> 56 57 #include <dev/ofw/ofw_bus.h> 58 #include <dev/ofw/openfirm.h> 59 60 struct riscv_timer_softc { 61 struct resource *irq_res; 62 void *ih; 63 uint32_t clkfreq; 64 struct eventtimer et; 65 }; 66 static struct riscv_timer_softc *riscv_timer_sc = NULL; 67 68 static timecounter_get_t riscv_timer_tc_get_timecount; 69 static timecounter_fill_vdso_timehands_t riscv_timer_tc_fill_vdso_timehands; 70 71 static struct timecounter riscv_timer_timecount = { 72 .tc_name = "RISC-V Timecounter", 73 .tc_get_timecount = riscv_timer_tc_get_timecount, 74 .tc_poll_pps = NULL, 75 .tc_counter_mask = ~0u, 76 .tc_frequency = 0, 77 .tc_quality = 1000, 78 .tc_fill_vdso_timehands = riscv_timer_tc_fill_vdso_timehands, 79 }; 80 81 static inline uint64_t 82 get_timecount(void) 83 { 84 85 return (rdtime()); 86 } 87 88 static inline void 89 set_timecmp(uint64_t timecmp) 90 { 91 92 if (has_sstc) 93 csr_write(stimecmp, timecmp); 94 else 95 sbi_set_timer(timecmp); 96 } 97 98 static u_int 99 riscv_timer_tc_get_timecount(struct timecounter *tc __unused) 100 { 101 102 return (get_timecount()); 103 } 104 105 static uint32_t 106 riscv_timer_tc_fill_vdso_timehands(struct vdso_timehands *vdso_th, 107 struct timecounter *tc) 108 { 109 vdso_th->th_algo = VDSO_TH_ALGO_RISCV_RDTIME; 110 bzero(vdso_th->th_res, sizeof(vdso_th->th_res)); 111 return (1); 112 } 113 114 static int 115 riscv_timer_et_start(struct eventtimer *et, sbintime_t first, sbintime_t period) 116 { 117 uint64_t counts; 118 119 if (first != 0) { 120 counts = ((uint32_t)et->et_frequency * first) >> 32; 121 set_timecmp(get_timecount() + counts); 122 123 return (0); 124 } 125 126 return (EINVAL); 127 } 128 129 static int 130 riscv_timer_et_stop(struct eventtimer *et) 131 { 132 133 /* Disable timer interrupts. */ 134 csr_clear(sie, SIE_STIE); 135 136 return (0); 137 } 138 139 static int 140 riscv_timer_intr(void *arg) 141 { 142 struct riscv_timer_softc *sc; 143 144 sc = (struct riscv_timer_softc *)arg; 145 146 if (has_sstc) 147 csr_write(stimecmp, -1UL); 148 else 149 csr_clear(sip, SIP_STIP); 150 151 if (sc->et.et_active) 152 sc->et.et_event_cb(&sc->et, sc->et.et_arg); 153 154 return (FILTER_HANDLED); 155 } 156 157 static int 158 riscv_timer_get_timebase(device_t dev, uint32_t *freq) 159 { 160 phandle_t node; 161 int len; 162 163 node = OF_finddevice("/cpus"); 164 if (node == -1) { 165 if (bootverbose) 166 device_printf(dev, "Can't find cpus node.\n"); 167 return (ENXIO); 168 } 169 170 len = OF_getproplen(node, "timebase-frequency"); 171 if (len != 4) { 172 if (bootverbose) 173 device_printf(dev, 174 "Can't find timebase-frequency property.\n"); 175 return (ENXIO); 176 } 177 178 OF_getencprop(node, "timebase-frequency", freq, len); 179 180 return (0); 181 } 182 183 static int 184 riscv_timer_probe(device_t dev) 185 { 186 187 device_set_desc(dev, "RISC-V Timer"); 188 189 return (BUS_PROBE_DEFAULT); 190 } 191 192 static int 193 riscv_timer_attach(device_t dev) 194 { 195 struct riscv_timer_softc *sc; 196 int irq, rid, error; 197 phandle_t iparent; 198 pcell_t cell; 199 device_t rootdev; 200 201 sc = device_get_softc(dev); 202 if (riscv_timer_sc != NULL) 203 return (ENXIO); 204 205 if (device_get_unit(dev) != 0) 206 return (ENXIO); 207 208 if (riscv_timer_get_timebase(dev, &sc->clkfreq) != 0) { 209 device_printf(dev, "No clock frequency specified\n"); 210 return (ENXIO); 211 } 212 213 riscv_timer_sc = sc; 214 215 rootdev = intr_irq_root_device(INTR_ROOT_IRQ); 216 iparent = OF_xref_from_node(ofw_bus_get_node(rootdev)); 217 cell = IRQ_TIMER_SUPERVISOR; 218 irq = ofw_bus_map_intr(dev, iparent, 1, &cell); 219 error = bus_set_resource(dev, SYS_RES_IRQ, 0, irq, 1); 220 if (error != 0) { 221 device_printf(dev, "Unable to register IRQ resource\n"); 222 return (ENXIO); 223 } 224 225 rid = 0; 226 sc->irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid, 227 RF_ACTIVE); 228 if (sc->irq_res == NULL) { 229 device_printf(dev, "Unable to alloc IRQ resource\n"); 230 return (ENXIO); 231 } 232 233 /* Setup IRQs handler */ 234 error = bus_setup_intr(dev, sc->irq_res, INTR_TYPE_CLK, 235 riscv_timer_intr, NULL, sc, &sc->ih); 236 if (error != 0) { 237 device_printf(dev, "Unable to setup IRQ resource\n"); 238 return (ENXIO); 239 } 240 241 riscv_timer_timecount.tc_frequency = sc->clkfreq; 242 riscv_timer_timecount.tc_priv = sc; 243 tc_init(&riscv_timer_timecount); 244 245 sc->et.et_name = "RISC-V Eventtimer"; 246 sc->et.et_flags = ET_FLAGS_ONESHOT | ET_FLAGS_PERCPU; 247 sc->et.et_quality = 1000; 248 249 sc->et.et_frequency = sc->clkfreq; 250 sc->et.et_min_period = (0x00000002LLU << 32) / sc->et.et_frequency; 251 sc->et.et_max_period = (0xfffffffeLLU << 32) / sc->et.et_frequency; 252 sc->et.et_start = riscv_timer_et_start; 253 sc->et.et_stop = riscv_timer_et_stop; 254 sc->et.et_priv = sc; 255 et_register(&sc->et); 256 257 set_cputicker(get_timecount, sc->clkfreq, false); 258 259 return (0); 260 } 261 262 static device_method_t riscv_timer_methods[] = { 263 DEVMETHOD(device_probe, riscv_timer_probe), 264 DEVMETHOD(device_attach, riscv_timer_attach), 265 { 0, 0 } 266 }; 267 268 static driver_t riscv_timer_driver = { 269 "timer", 270 riscv_timer_methods, 271 sizeof(struct riscv_timer_softc), 272 }; 273 274 EARLY_DRIVER_MODULE(timer, nexus, riscv_timer_driver, 0, 0, 275 BUS_PASS_TIMER + BUS_PASS_ORDER_MIDDLE); 276 277 void 278 DELAY(int usec) 279 { 280 int64_t counts, counts_per_usec; 281 uint64_t first, last; 282 283 /* 284 * Check the timers are setup, if not just 285 * use a for loop for the meantime 286 */ 287 if (riscv_timer_sc == NULL) { 288 for (; usec > 0; usec--) 289 for (counts = 200; counts > 0; counts--) 290 /* 291 * Prevent the compiler from optimizing 292 * out the loop 293 */ 294 cpufunc_nullop(); 295 return; 296 } 297 TSENTER(); 298 299 /* Get the number of times to count */ 300 counts_per_usec = ((riscv_timer_timecount.tc_frequency / 1000000) + 1); 301 302 /* 303 * Clamp the timeout at a maximum value (about 32 seconds with 304 * a 66MHz clock). *Nobody* should be delay()ing for anywhere 305 * near that length of time and if they are, they should be hung 306 * out to dry. 307 */ 308 if (usec >= (0x80000000U / counts_per_usec)) 309 counts = (0x80000000U / counts_per_usec) - 1; 310 else 311 counts = usec * counts_per_usec; 312 313 first = get_timecount(); 314 315 while (counts > 0) { 316 last = get_timecount(); 317 counts -= (int64_t)(last - first); 318 first = last; 319 } 320 TSEXIT(); 321 } 322