hw/mips: add initial Cluster Power Controller support

Cluster Power Controller (CPC) is responsible for power management in
multiprocessing system. It provides registers to control the power and the
clock frequency of the individual elements in the system.

This patch implements only three registers that are used to control the
power state of each VP on a single core:
* VP Run is a write-only register used to set each VP to the run state
* VP Stop is a write-only register used to set each VP to the suspend state
* VP Running is a read-only register indicating the run state of each VP

Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>

3 files changed, 225 insertions, 0 deletions

diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
index b00a5d00d0..78052625b5 100644
--- a/hw/misc/Makefile.objs
+++ b/hw/misc/Makefile.objs
@@ -44,6 +44,7 @@ obj-$(CONFIG_ZYNQ) += zynq_slcr.o
 obj-$(CONFIG_ZYNQ) += zynq-xadc.o
 obj-$(CONFIG_STM32F2XX_SYSCFG) += stm32f2xx_syscfg.o
 obj-$(CONFIG_MIPS_CPS) += mips_cmgcr.o
+obj-$(CONFIG_MIPS_CPS) += mips_cpc.o
 
 obj-$(CONFIG_PVPANIC) += pvpanic.o
 obj-$(CONFIG_EDU) += edu.o
diff --git a/hw/misc/mips_cpc.c b/hw/misc/mips_cpc.c
new file mode 100644
index 0000000000..d2b8e42da7
--- /dev/null
+++ b/hw/misc/mips_cpc.c
@@ -0,0 +1,177 @@
+/*
+ * Cluster Power Controller emulation
+ *
+ * Copyright (c) 2016 Imagination Technologies
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "hw/sysbus.h"
+
+#include "hw/misc/mips_cpc.h"
+
+static inline uint64_t cpc_vp_run_mask(MIPSCPCState *cpc)
+{
+    return (1ULL << cpc->num_vp) - 1;
+}
+
+static void cpc_run_vp(MIPSCPCState *cpc, uint64_t vp_run)
+{
+    CPUState *cs = first_cpu;
+
+    CPU_FOREACH(cs) {
+        uint64_t i = 1ULL << cs->cpu_index;
+        if (i & vp_run & ~cpc->vp_running) {
+            cpu_interrupt(cs, CPU_INTERRUPT_WAKE);
+            cpc->vp_running |= i;
+        }
+    }
+}
+
+static void cpc_stop_vp(MIPSCPCState *cpc, uint64_t vp_stop)
+{
+    CPUState *cs = first_cpu;
+
+    CPU_FOREACH(cs) {
+        uint64_t i = 1ULL << cs->cpu_index;
+        if (i & vp_stop & cpc->vp_running) {
+            cs->halted = 1;
+            cpu_reset_interrupt(cs, CPU_INTERRUPT_WAKE);
+            cpc->vp_running &= ~i;
+        }
+    }
+}
+
+static void cpc_write(void *opaque, hwaddr offset, uint64_t data,
+                      unsigned size)
+{
+    MIPSCPCState *s = opaque;
+
+    switch (offset) {
+    case CPC_CL_BASE_OFS + CPC_VP_RUN_OFS:
+    case CPC_CO_BASE_OFS + CPC_VP_RUN_OFS:
+        cpc_run_vp(s, data & cpc_vp_run_mask(s));
+        break;
+    case CPC_CL_BASE_OFS + CPC_VP_STOP_OFS:
+    case CPC_CO_BASE_OFS + CPC_VP_STOP_OFS:
+        cpc_stop_vp(s, data & cpc_vp_run_mask(s));
+        break;
+    default:
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: Bad offset 0x%x\n",  __func__, (int)offset);
+        break;
+    }
+
+    return;
+}
+
+static uint64_t cpc_read(void *opaque, hwaddr offset, unsigned size)
+{
+    MIPSCPCState *s = opaque;
+
+    switch (offset) {
+    case CPC_CL_BASE_OFS + CPC_VP_RUNNING_OFS:
+    case CPC_CO_BASE_OFS + CPC_VP_RUNNING_OFS:
+        return s->vp_running;
+    default:
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: Bad offset 0x%x\n",  __func__, (int)offset);
+        return 0;
+    }
+}
+
+static const MemoryRegionOps cpc_ops = {
+    .read = cpc_read,
+    .write = cpc_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .impl = {
+        .max_access_size = 8,
+    },
+};
+
+static void mips_cpc_init(Object *obj)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    MIPSCPCState *s = MIPS_CPC(obj);
+
+    memory_region_init_io(&s->mr, OBJECT(s), &cpc_ops, s, "mips-cpc",
+                          CPC_ADDRSPACE_SZ);
+    sysbus_init_mmio(sbd, &s->mr);
+}
+
+static void mips_cpc_realize(DeviceState *dev, Error **errp)
+{
+    MIPSCPCState *s = MIPS_CPC(dev);
+
+    if (s->vp_start_running > cpc_vp_run_mask(s)) {
+        error_setg(errp,
+                   "incorrect vp_start_running 0x%" PRIx64 " for num_vp = %d",
+                   s->vp_running, s->num_vp);
+        return;
+    }
+}
+
+static void mips_cpc_reset(DeviceState *dev)
+{
+    MIPSCPCState *s = MIPS_CPC(dev);
+
+    /* Reflect the fact that all VPs are halted on reset */
+    s->vp_running = 0;
+
+    /* Put selected VPs into run state */
+    cpc_run_vp(s, s->vp_start_running);
+}
+
+static const VMStateDescription vmstate_mips_cpc = {
+    .name = "mips-cpc",
+    .version_id = 0,
+    .minimum_version_id = 0,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(vp_running, MIPSCPCState),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
+static Property mips_cpc_properties[] = {
+    DEFINE_PROP_UINT32("num-vp", MIPSCPCState, num_vp, 0x1),
+    DEFINE_PROP_UINT64("vp-start-running", MIPSCPCState, vp_start_running, 0x1),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void mips_cpc_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = mips_cpc_realize;
+    dc->reset = mips_cpc_reset;
+    dc->vmsd = &vmstate_mips_cpc;
+    dc->props = mips_cpc_properties;
+}
+
+static const TypeInfo mips_cpc_info = {
+    .name          = TYPE_MIPS_CPC,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(MIPSCPCState),
+    .instance_init = mips_cpc_init,
+    .class_init    = mips_cpc_class_init,
+};
+
+static void mips_cpc_register_types(void)
+{
+    type_register_static(&mips_cpc_info);
+}
+
+type_init(mips_cpc_register_types)
diff --git a/include/hw/misc/mips_cpc.h b/include/hw/misc/mips_cpc.h
new file mode 100644
index 0000000000..72c834e039
--- /dev/null
+++ b/include/hw/misc/mips_cpc.h
@@ -0,0 +1,47 @@
+/*
+ * Cluster Power Controller emulation
+ *
+ * Copyright (c) 2016 Imagination Technologies
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef MIPS_CPC_H
+#define MIPS_CPC_H
+
+#define CPC_ADDRSPACE_SZ    0x6000
+
+/* CPC blocks offsets relative to base address */
+#define CPC_CL_BASE_OFS     0x2000
+#define CPC_CO_BASE_OFS     0x4000
+
+/* CPC register offsets relative to block offsets */
+#define CPC_VP_STOP_OFS     0x20
+#define CPC_VP_RUN_OFS      0x28
+#define CPC_VP_RUNNING_OFS  0x30
+
+#define TYPE_MIPS_CPC "mips-cpc"
+#define MIPS_CPC(obj) OBJECT_CHECK(MIPSCPCState, (obj), TYPE_MIPS_CPC)
+
+typedef struct MIPSCPCState {
+    SysBusDevice parent_obj;
+
+    uint32_t num_vp;
+    uint64_t vp_start_running; /* VPs running from restart */
+
+    MemoryRegion mr;
+    uint64_t vp_running; /* Indicates which VPs are in the run state */
+} MIPSCPCState;
+
+#endif /* MIPS_CPC_H */