hw/riscv/sifive_prci.c

   1 /*
   2  * QEMU SiFive PRCI (Power, Reset, Clock, Interrupt)
   3  *
   4  * Copyright (c) 2017 SiFive, Inc.
   5  *
   6  * Simple model of the PRCI to emulate register reads made by the SDK BSP
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2 or later, as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along with
  18  * this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "hw/sysbus.h"
  23 #include "qemu/module.h"
  24 #include "target/riscv/cpu.h"
  25 #include "hw/riscv/sifive_prci.h"
  26
  27 /* currently implements enough to mock freedom-e-sdk BSP clock programming */
  28
  29 static uint64_t sifive_prci_read(void *opaque, hwaddr addr, unsigned int size)
  30 {
  31     if (addr == 0 /* PRCI_HFROSCCFG */) {
  32         return 1 << 31; /* ROSC_RDY */
  33     }
  34     if (addr == 8 /* PRCI_PLLCFG    */) {
  35         return 1 << 31; /* PLL_LOCK */
  36     }
  37     hw_error("%s: read: addr=0x%x\n", __func__, (int)addr);
  38     return 0;
  39 }
  40
  41 static void sifive_prci_write(void *opaque, hwaddr addr,
  42            uint64_t val64, unsigned int size)
  43 {
  44     /* discard writes */
  45 }
  46
  47 static const MemoryRegionOps sifive_prci_ops = {
  48     .read = sifive_prci_read,
  49     .write = sifive_prci_write,
  50     .endianness = DEVICE_NATIVE_ENDIAN,
  51     .valid = {
  52         .min_access_size = 4,
  53         .max_access_size = 4
  54     }
  55 };
  56
  57 static void sifive_prci_init(Object *obj)
  58 {
  59     SiFivePRCIState *s = SIFIVE_PRCI(obj);
  60
  61     memory_region_init_io(&s->mmio, obj, &sifive_prci_ops, s,
  62                           TYPE_SIFIVE_PRCI, 0x8000);
  63     sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
  64 }
  65
  66 static const TypeInfo sifive_prci_info = {
  67     .name          = TYPE_SIFIVE_PRCI,
  68     .parent        = TYPE_SYS_BUS_DEVICE,
  69     .instance_size = sizeof(SiFivePRCIState),
  70     .instance_init = sifive_prci_init,
  71 };
  72
  73 static void sifive_prci_register_types(void)
  74 {
  75     type_register_static(&sifive_prci_info);
  76 }
  77
  78 type_init(sifive_prci_register_types)
  79
  80
  81 /*
  82  * Create PRCI device.
  83  */
  84 DeviceState *sifive_prci_create(hwaddr addr)
  85 {
  86     DeviceState *dev = qdev_create(NULL, TYPE_SIFIVE_PRCI);
  87     qdev_init_nofail(dev);
  88     sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, addr);
  89     return dev;
  90 }