SiFive RISC-V PRCI Block

Simple model of the PRCI  (Power, Reset, Clock, Interrupt) to emulate
register reads made by the SDK BSP.

Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Michael Clark <mjc@sifive.com>

hw/riscv/sifive_prci.c

@@ -0,0 +1,89 @@
+/*
+ * QEMU SiFive PRCI (Power, Reset, Clock, Interrupt)
+ *
+ * Copyright (c) 2017 SiFive, Inc.
+ *
+ * Simple model of the PRCI to emulate register reads made by the SDK BSP
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/sysbus.h"
+#include "target/riscv/cpu.h"
+#include "hw/riscv/sifive_prci.h"
+
+/* currently implements enough to mock freedom-e-sdk BSP clock programming */
+
+static uint64_t sifive_prci_read(void *opaque, hwaddr addr, unsigned int size)
+{
+    if (addr == 0 /* PRCI_HFROSCCFG */) {
+        return 1 << 31; /* ROSC_RDY */
+    }
+    if (addr == 8 /* PRCI_PLLCFG    */) {
+        return 1 << 31; /* PLL_LOCK */
+    }
+    hw_error("%s: read: addr=0x%x\n", __func__, (int)addr);
+    return 0;
+}
+
+static void sifive_prci_write(void *opaque, hwaddr addr,
+           uint64_t val64, unsigned int size)
+{
+    /* discard writes */
+}
+
+static const MemoryRegionOps sifive_prci_ops = {
+    .read = sifive_prci_read,
+    .write = sifive_prci_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4
+    }
+};
+
+static void sifive_prci_init(Object *obj)
+{
+    SiFivePRCIState *s = SIFIVE_PRCI(obj);
+
+    memory_region_init_io(&s->mmio, obj, &sifive_prci_ops, s,
+                          TYPE_SIFIVE_PRCI, 0x8000);
+    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
+}
+
+static const TypeInfo sifive_prci_info = {
+    .name          = TYPE_SIFIVE_PRCI,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(SiFivePRCIState),
+    .instance_init = sifive_prci_init,
+};
+
+static void sifive_prci_register_types(void)
+{
+    type_register_static(&sifive_prci_info);
+}
+
+type_init(sifive_prci_register_types)
+
+
+/*
+ * Create PRCI device.
+ */
+DeviceState *sifive_prci_create(hwaddr addr)
+{
+    DeviceState *dev = qdev_create(NULL, TYPE_SIFIVE_PRCI);
+    qdev_init_nofail(dev);
+    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, addr);
+    return dev;
+}

include/hw/riscv/sifive_prci.h

@@ -0,0 +1,37 @@
+/*
+ * QEMU SiFive PRCI (Power, Reset, Clock, Interrupt) interface
+ *
+ * Copyright (c) 2017 SiFive, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef HW_SIFIVE_PRCI_H
+#define HW_SIFIVE_PRCI_H
+
+#define TYPE_SIFIVE_PRCI "riscv.sifive.prci"
+
+#define SIFIVE_PRCI(obj) \
+    OBJECT_CHECK(SiFivePRCIState, (obj), TYPE_SIFIVE_PRCI)
+
+typedef struct SiFivePRCIState {
+    /*< private >*/
+    SysBusDevice parent_obj;
+
+    /*< public >*/
+    MemoryRegion mmio;
+} SiFivePRCIState;
+
+DeviceState *sifive_prci_create(hwaddr addr);
+
+#endif