openrisc/ompic: Add OpenRISC Multicore PIC (OMPIC)

Add OpenRISC Multicore PIC which handles inter processor interrupts
(IPI) between cores.  In OpenRISC all device interrupts are routed to
each core enabling this device to be simple.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Stafford Horne <shorne@gmail.com>

3 files changed, 181 insertions, 0 deletions

diff --git a/default-configs/or1k-softmmu.mak b/default-configs/or1k-softmmu.mak
index 10bfa7abb8..6f5824fd48 100644
--- a/default-configs/or1k-softmmu.mak
+++ b/default-configs/or1k-softmmu.mak
@@ -2,3 +2,4 @@
 
 CONFIG_SERIAL=y
 CONFIG_OPENCORES_ETH=y
+CONFIG_OMPIC=y
diff --git a/hw/intc/Makefile.objs b/hw/intc/Makefile.objs
index 78426a7daf..ae358569a1 100644
--- a/hw/intc/Makefile.objs
+++ b/hw/intc/Makefile.objs
@@ -43,3 +43,4 @@ obj-$(CONFIG_ASPEED_SOC) += aspeed_vic.o
 obj-$(CONFIG_ARM_GIC) += arm_gicv3_cpuif.o
 obj-$(CONFIG_MIPS_CPS) += mips_gic.o
 obj-$(CONFIG_NIOS2) += nios2_iic.o
+obj-$(CONFIG_OMPIC) += ompic.o
diff --git a/hw/intc/ompic.c b/hw/intc/ompic.c
new file mode 100644
index 0000000000..c0e34d1268
--- /dev/null
+++ b/hw/intc/ompic.c
@@ -0,0 +1,179 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Authors: Stafford Horne <shorne@gmail.com>
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "qapi/error.h"
+#include "hw/hw.h"
+#include "hw/sysbus.h"
+#include "exec/memory.h"
+
+#define TYPE_OR1K_OMPIC "or1k-ompic"
+#define OR1K_OMPIC(obj) OBJECT_CHECK(OR1KOMPICState, (obj), TYPE_OR1K_OMPIC)
+
+#define OMPIC_CTRL_IRQ_ACK  (1 << 31)
+#define OMPIC_CTRL_IRQ_GEN  (1 << 30)
+#define OMPIC_CTRL_DST(cpu) (((cpu) >> 16) & 0x3fff)
+
+#define OMPIC_REG(addr)     (((addr) >> 2) & 0x1)
+#define OMPIC_SRC_CPU(addr) (((addr) >> 3) & 0x4f)
+#define OMPIC_DST_CPU(addr) (((addr) >> 3) & 0x4f)
+
+#define OMPIC_STATUS_IRQ_PENDING (1 << 30)
+#define OMPIC_STATUS_SRC(cpu)    (((cpu) & 0x3fff) << 16)
+#define OMPIC_STATUS_DATA(data)  ((data) & 0xffff)
+
+#define OMPIC_CONTROL 0
+#define OMPIC_STATUS  1
+
+#define OMPIC_MAX_CPUS 4 /* Real max is much higher, but dont waste memory */
+#define OMPIC_ADDRSPACE_SZ (OMPIC_MAX_CPUS * 2 * 4) /* 2 32-bit regs per cpu */
+
+typedef struct OR1KOMPICState OR1KOMPICState;
+typedef struct OR1KOMPICCPUState OR1KOMPICCPUState;
+
+struct OR1KOMPICCPUState {
+    qemu_irq irq;
+    uint32_t status;
+    uint32_t control;
+};
+
+struct OR1KOMPICState {
+    SysBusDevice parent_obj;
+    MemoryRegion mr;
+
+    OR1KOMPICCPUState cpus[OMPIC_MAX_CPUS];
+
+    uint32_t num_cpus;
+};
+
+static uint64_t ompic_read(void *opaque, hwaddr addr, unsigned size)
+{
+    OR1KOMPICState *s = opaque;
+    int src_cpu = OMPIC_SRC_CPU(addr);
+
+    /* We can only write to control control, write control + update status */
+    if (OMPIC_REG(addr) == OMPIC_CONTROL) {
+        return s->cpus[src_cpu].control;
+    } else {
+        return s->cpus[src_cpu].status;
+   }
+
+}
+
+static void ompic_write(void *opaque, hwaddr addr, uint64_t data, unsigned size)
+{
+    OR1KOMPICState *s = opaque;
+    /* We can only write to control control, write control + update status */
+    if (OMPIC_REG(addr) == OMPIC_CONTROL) {
+        int src_cpu = OMPIC_SRC_CPU(addr);
+
+        s->cpus[src_cpu].control = data;
+
+        if (data & OMPIC_CTRL_IRQ_GEN) {
+            int dst_cpu = OMPIC_CTRL_DST(data);
+
+            s->cpus[dst_cpu].status = OMPIC_STATUS_IRQ_PENDING |
+                OMPIC_STATUS_SRC(src_cpu) |
+                OMPIC_STATUS_DATA(data);
+
+            qemu_irq_raise(s->cpus[dst_cpu].irq);
+        }
+        if (data & OMPIC_CTRL_IRQ_ACK) {
+            s->cpus[src_cpu].status &= ~OMPIC_STATUS_IRQ_PENDING;
+            qemu_irq_lower(s->cpus[src_cpu].irq);
+        }
+    }
+}
+
+static const MemoryRegionOps ompic_ops = {
+    .read = ompic_read,
+    .write = ompic_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .impl = {
+        .max_access_size = 8,
+    },
+};
+
+static void or1k_ompic_init(Object *obj)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    OR1KOMPICState *s = OR1K_OMPIC(obj);
+
+    memory_region_init_io(&s->mr, OBJECT(s), &ompic_ops, s,
+                          "or1k-ompic", OMPIC_ADDRSPACE_SZ);
+    sysbus_init_mmio(sbd, &s->mr);
+}
+
+static void or1k_ompic_realize(DeviceState *dev, Error **errp)
+{
+    OR1KOMPICState *s = OR1K_OMPIC(dev);
+    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+    int i;
+
+    if (s->num_cpus > OMPIC_MAX_CPUS) {
+        error_setg(errp, "Exceeded maximum CPUs %d", s->num_cpus);
+        return;
+    }
+    /* Init IRQ sources for all CPUs */
+    for (i = 0; i < s->num_cpus; i++) {
+        sysbus_init_irq(sbd, &s->cpus[i].irq);
+    }
+}
+
+static Property or1k_ompic_properties[] = {
+    DEFINE_PROP_UINT32("num-cpus", OR1KOMPICState, num_cpus, 1),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static const VMStateDescription vmstate_or1k_ompic_cpu = {
+    .name = "or1k_ompic_cpu",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+         VMSTATE_UINT32(status, OR1KOMPICCPUState),
+         VMSTATE_UINT32(control, OR1KOMPICCPUState),
+         VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_or1k_ompic = {
+    .name = TYPE_OR1K_OMPIC,
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+         VMSTATE_STRUCT_ARRAY(cpus, OR1KOMPICState, OMPIC_MAX_CPUS, 1,
+             vmstate_or1k_ompic_cpu, OR1KOMPICCPUState),
+         VMSTATE_UINT32(num_cpus, OR1KOMPICState),
+         VMSTATE_END_OF_LIST()
+    }
+};
+
+static void or1k_ompic_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->props = or1k_ompic_properties;
+    dc->realize = or1k_ompic_realize;
+    dc->vmsd = &vmstate_or1k_ompic;
+}
+
+static const TypeInfo or1k_ompic_info = {
+    .name          = TYPE_OR1K_OMPIC,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(OR1KOMPICState),
+    .instance_init = or1k_ompic_init,
+    .class_init    = or1k_ompic_class_init,
+};
+
+static void or1k_ompic_register_types(void)
+{
+    type_register_static(&or1k_ompic_info);
+}
+
+type_init(or1k_ompic_register_types)