hw/riscv/sifive_clint.c

   1 /*
   2  * SiFive CLINT (Core Local Interruptor)
   3  *
   4  * Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu
   5  * Copyright (c) 2017 SiFive, Inc.
   6  *
   7  * This provides real-time clock, timer and interprocessor interrupts.
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms and conditions of the GNU General Public License,
  11  * version 2 or later, as published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope it will be useful, but WITHOUT
  14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  16  * more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along with
  19  * this program.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include "qemu/osdep.h"
  23 #include "qemu/error-report.h"
  24 #include "hw/sysbus.h"
  25 #include "target/riscv/cpu.h"
  26 #include "hw/riscv/sifive_clint.h"
  27 #include "qemu/timer.h"
  28
  29 /* See: riscv-pk/machine/sbi_entry.S and arch/riscv/kernel/time.c */
  30 #define TIMER_FREQ (10 * 1000 * 1000)
  31
  32 static uint64_t cpu_riscv_read_rtc(void)
  33 {
  34     return muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL), TIMER_FREQ,
  35                     NANOSECONDS_PER_SECOND);
  36 }
  37
  38 /*
  39  * Called when timecmp is written to update the QEMU timer or immediately
  40  * trigger timer interrupt if mtimecmp <= current timer value.
  41  */
  42 static void sifive_clint_write_timecmp(RISCVCPU *cpu, uint64_t value)
  43 {
  44     uint64_t next;
  45     uint64_t diff;
  46
  47     uint64_t rtc_r = cpu_riscv_read_rtc();
  48
  49     cpu->env.timecmp = value;
  50     if (cpu->env.timecmp <= rtc_r) {
  51         /* if we're setting an MTIMECMP value in the "past",
  52            immediately raise the timer interrupt */
  53         riscv_set_local_interrupt(cpu, MIP_MTIP, 1);
  54         return;
  55     }
  56
  57     /* otherwise, set up the future timer interrupt */
  58     riscv_set_local_interrupt(cpu, MIP_MTIP, 0);
  59     diff = cpu->env.timecmp - rtc_r;
  60     /* back to ns (note args switched in muldiv64) */
  61     next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
  62         muldiv64(diff, NANOSECONDS_PER_SECOND, TIMER_FREQ);
  63     timer_mod(cpu->env.timer, next);
  64 }
  65
  66 /*
  67  * Callback used when the timer set using timer_mod expires.
  68  * Should raise the timer interrupt line
  69  */
  70 static void sifive_clint_timer_cb(void *opaque)
  71 {
  72     RISCVCPU *cpu = opaque;
  73     riscv_set_local_interrupt(cpu, MIP_MTIP, 1);
  74 }
  75
  76 /* CPU wants to read rtc or timecmp register */
  77 static uint64_t sifive_clint_read(void *opaque, hwaddr addr, unsigned size)
  78 {
  79     SiFiveCLINTState *clint = opaque;
  80     if (addr >= clint->sip_base &&
  81         addr < clint->sip_base + (clint->num_harts << 2)) {
  82         size_t hartid = (addr - clint->sip_base) >> 2;
  83         CPUState *cpu = qemu_get_cpu(hartid);
  84         CPURISCVState *env = cpu ? cpu->env_ptr : NULL;
  85         if (!env) {
  86             error_report("clint: invalid timecmp hartid: %zu", hartid);
  87         } else if ((addr & 0x3) == 0) {
  88             return (env->mip & MIP_MSIP) > 0;
  89         } else {
  90             error_report("clint: invalid read: %08x", (uint32_t)addr);
  91             return 0;
  92         }
  93     } else if (addr >= clint->timecmp_base &&
  94         addr < clint->timecmp_base + (clint->num_harts << 3)) {
  95         size_t hartid = (addr - clint->timecmp_base) >> 3;
  96         CPUState *cpu = qemu_get_cpu(hartid);
  97         CPURISCVState *env = cpu ? cpu->env_ptr : NULL;
  98         if (!env) {
  99             error_report("clint: invalid timecmp hartid: %zu", hartid);
 100         } else if ((addr & 0x7) == 0) {
 101             /* timecmp_lo */
 102             uint64_t timecmp = env->timecmp;
 103             return timecmp & 0xFFFFFFFF;
 104         } else if ((addr & 0x7) == 4) {
 105             /* timecmp_hi */
 106             uint64_t timecmp = env->timecmp;
 107             return (timecmp >> 32) & 0xFFFFFFFF;
 108         } else {
 109             error_report("clint: invalid read: %08x", (uint32_t)addr);
 110             return 0;
 111         }
 112     } else if (addr == clint->time_base) {
 113         /* time_lo */
 114         return cpu_riscv_read_rtc() & 0xFFFFFFFF;
 115     } else if (addr == clint->time_base + 4) {
 116         /* time_hi */
 117         return (cpu_riscv_read_rtc() >> 32) & 0xFFFFFFFF;
 118     }
 119
 120     error_report("clint: invalid read: %08x", (uint32_t)addr);
 121     return 0;
 122 }
 123
 124 /* CPU wrote to rtc or timecmp register */
 125 static void sifive_clint_write(void *opaque, hwaddr addr, uint64_t value,
 126         unsigned size)
 127 {
 128     SiFiveCLINTState *clint = opaque;
 129
 130     if (addr >= clint->sip_base &&
 131         addr < clint->sip_base + (clint->num_harts << 2)) {
 132         size_t hartid = (addr - clint->sip_base) >> 2;
 133         CPUState *cpu = qemu_get_cpu(hartid);
 134         CPURISCVState *env = cpu ? cpu->env_ptr : NULL;
 135         if (!env) {
 136             error_report("clint: invalid timecmp hartid: %zu", hartid);
 137         } else if ((addr & 0x3) == 0) {
 138             riscv_set_local_interrupt(RISCV_CPU(cpu), MIP_MSIP, value != 0);
 139         } else {
 140             error_report("clint: invalid sip write: %08x", (uint32_t)addr);
 141         }
 142         return;
 143     } else if (addr >= clint->timecmp_base &&
 144         addr < clint->timecmp_base + (clint->num_harts << 3)) {
 145         size_t hartid = (addr - clint->timecmp_base) >> 3;
 146         CPUState *cpu = qemu_get_cpu(hartid);
 147         CPURISCVState *env = cpu ? cpu->env_ptr : NULL;
 148         if (!env) {
 149             error_report("clint: invalid timecmp hartid: %zu", hartid);
 150         } else if ((addr & 0x7) == 0) {
 151             /* timecmp_lo */
 152             uint64_t timecmp = env->timecmp;
 153             sifive_clint_write_timecmp(RISCV_CPU(cpu),
 154                 timecmp << 32 | (value & 0xFFFFFFFF));
 155             return;
 156         } else if ((addr & 0x7) == 4) {
 157             /* timecmp_hi */
 158             uint64_t timecmp = env->timecmp;
 159             sifive_clint_write_timecmp(RISCV_CPU(cpu),
 160                 value << 32 | (timecmp & 0xFFFFFFFF));
 161         } else {
 162             error_report("clint: invalid timecmp write: %08x", (uint32_t)addr);
 163         }
 164         return;
 165     } else if (addr == clint->time_base) {
 166         /* time_lo */
 167         error_report("clint: time_lo write not implemented");
 168         return;
 169     } else if (addr == clint->time_base + 4) {
 170         /* time_hi */
 171         error_report("clint: time_hi write not implemented");
 172         return;
 173     }
 174
 175     error_report("clint: invalid write: %08x", (uint32_t)addr);
 176 }
 177
 178 static const MemoryRegionOps sifive_clint_ops = {
 179     .read = sifive_clint_read,
 180     .write = sifive_clint_write,
 181     .endianness = DEVICE_LITTLE_ENDIAN,
 182     .valid = {
 183         .min_access_size = 4,
 184         .max_access_size = 4
 185     }
 186 };
 187
 188 static Property sifive_clint_properties[] = {
 189     DEFINE_PROP_UINT32("num-harts", SiFiveCLINTState, num_harts, 0),
 190     DEFINE_PROP_UINT32("sip-base", SiFiveCLINTState, sip_base, 0),
 191     DEFINE_PROP_UINT32("timecmp-base", SiFiveCLINTState, timecmp_base, 0),
 192     DEFINE_PROP_UINT32("time-base", SiFiveCLINTState, time_base, 0),
 193     DEFINE_PROP_UINT32("aperture-size", SiFiveCLINTState, aperture_size, 0),
 194     DEFINE_PROP_END_OF_LIST(),
 195 };
 196
 197 static void sifive_clint_realize(DeviceState *dev, Error **errp)
 198 {
 199     SiFiveCLINTState *s = SIFIVE_CLINT(dev);
 200     memory_region_init_io(&s->mmio, OBJECT(dev), &sifive_clint_ops, s,
 201                           TYPE_SIFIVE_CLINT, s->aperture_size);
 202     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->mmio);
 203 }
 204
 205 static void sifive_clint_class_init(ObjectClass *klass, void *data)
 206 {
 207     DeviceClass *dc = DEVICE_CLASS(klass);
 208     dc->realize = sifive_clint_realize;
 209     dc->props = sifive_clint_properties;
 210 }
 211
 212 static const TypeInfo sifive_clint_info = {
 213     .name          = TYPE_SIFIVE_CLINT,
 214     .parent        = TYPE_SYS_BUS_DEVICE,
 215     .instance_size = sizeof(SiFiveCLINTState),
 216     .class_init    = sifive_clint_class_init,
 217 };
 218
 219 static void sifive_clint_register_types(void)
 220 {
 221     type_register_static(&sifive_clint_info);
 222 }
 223
 224 type_init(sifive_clint_register_types)
 225
 226
 227 /*
 228  * Create CLINT device.
 229  */
 230 DeviceState *sifive_clint_create(hwaddr addr, hwaddr size, uint32_t num_harts,
 231     uint32_t sip_base, uint32_t timecmp_base, uint32_t time_base)
 232 {
 233     int i;
 234     for (i = 0; i < num_harts; i++) {
 235         CPUState *cpu = qemu_get_cpu(i);
 236         CPURISCVState *env = cpu ? cpu->env_ptr : NULL;
 237         if (!env) {
 238             continue;
 239         }
 240         env->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
 241                                   &sifive_clint_timer_cb, cpu);
 242         env->timecmp = 0;
 243     }
 244
 245     DeviceState *dev = qdev_create(NULL, TYPE_SIFIVE_CLINT);
 246     qdev_prop_set_uint32(dev, "num-harts", num_harts);
 247     qdev_prop_set_uint32(dev, "sip-base", sip_base);
 248     qdev_prop_set_uint32(dev, "timecmp-base", timecmp_base);
 249     qdev_prop_set_uint32(dev, "time-base", time_base);
 250     qdev_prop_set_uint32(dev, "aperture-size", size);
 251     qdev_init_nofail(dev);
 252     sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, addr);
 253     return dev;
 254 }