hw/misc/armsse-mhu.c: Model the SSE-200 Message Handling Unit

Implement a model of the Message Handling Unit (MHU) found in
the Arm SSE-200. This is a simple device which just contains
some registers which allow the two cores of the SSE-200
to raise interrupts on each other.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20190219125808.25174-2-peter.maydell@linaro.org

3 files changed, 203 insertions, 0 deletions

diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
index 74c91d250c..c71e07ae35 100644
--- a/hw/misc/Makefile.objs
+++ b/hw/misc/Makefile.objs
@@ -70,6 +70,7 @@ obj-$(CONFIG_IOTKIT_SECCTL) += iotkit-secctl.o
 obj-$(CONFIG_IOTKIT_SYSCTL) += iotkit-sysctl.o
 obj-$(CONFIG_IOTKIT_SYSINFO) += iotkit-sysinfo.o
 obj-$(CONFIG_ARMSSE_CPUID) += armsse-cpuid.o
+obj-$(CONFIG_ARMSSE_MHU) += armsse-mhu.o
 
 obj-$(CONFIG_PVPANIC) += pvpanic.o
 obj-$(CONFIG_AUX) += auxbus.o
diff --git a/hw/misc/armsse-mhu.c b/hw/misc/armsse-mhu.c
new file mode 100644
index 0000000000..9ebca32e9a
--- /dev/null
+++ b/hw/misc/armsse-mhu.c
@@ -0,0 +1,198 @@
+/*
+ * ARM SSE-200 Message Handling Unit (MHU)
+ *
+ * Copyright (c) 2019 Linaro Limited
+ * Written by Peter Maydell
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 or
+ *  (at your option) any later version.
+ */
+
+/*
+ * This is a model of the Message Handling Unit (MHU) which is part of the
+ * Arm SSE-200 and documented in
+ * http://infocenter.arm.com/help/topic/com.arm.doc.101104_0100_00_en/corelink_sse200_subsystem_for_embedded_technical_reference_manual_101104_0100_00_en.pdf
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "trace.h"
+#include "qapi/error.h"
+#include "sysemu/sysemu.h"
+#include "hw/sysbus.h"
+#include "hw/registerfields.h"
+#include "hw/misc/armsse-mhu.h"
+
+REG32(CPU0INTR_STAT, 0x0)
+REG32(CPU0INTR_SET, 0x4)
+REG32(CPU0INTR_CLR, 0x8)
+REG32(CPU1INTR_STAT, 0x10)
+REG32(CPU1INTR_SET, 0x14)
+REG32(CPU1INTR_CLR, 0x18)
+REG32(PID4, 0xfd0)
+REG32(PID5, 0xfd4)
+REG32(PID6, 0xfd8)
+REG32(PID7, 0xfdc)
+REG32(PID0, 0xfe0)
+REG32(PID1, 0xfe4)
+REG32(PID2, 0xfe8)
+REG32(PID3, 0xfec)
+REG32(CID0, 0xff0)
+REG32(CID1, 0xff4)
+REG32(CID2, 0xff8)
+REG32(CID3, 0xffc)
+
+/* Valid bits in the interrupt registers. If any are set the IRQ is raised */
+#define INTR_MASK 0xf
+
+/* PID/CID values */
+static const int armsse_mhu_id[] = {
+    0x04, 0x00, 0x00, 0x00, /* PID4..PID7 */
+    0x56, 0xb8, 0x0b, 0x00, /* PID0..PID3 */
+    0x0d, 0xf0, 0x05, 0xb1, /* CID0..CID3 */
+};
+
+static void armsse_mhu_update(ARMSSEMHU *s)
+{
+    qemu_set_irq(s->cpu0irq, s->cpu0intr != 0);
+    qemu_set_irq(s->cpu1irq, s->cpu1intr != 0);
+}
+
+static uint64_t armsse_mhu_read(void *opaque, hwaddr offset, unsigned size)
+{
+    ARMSSEMHU *s = ARMSSE_MHU(opaque);
+    uint64_t r;
+
+    switch (offset) {
+    case A_CPU0INTR_STAT:
+        r = s->cpu0intr;
+        break;
+
+    case A_CPU1INTR_STAT:
+        r = s->cpu1intr;
+        break;
+
+    case A_PID4 ... A_CID3:
+        r = armsse_mhu_id[(offset - A_PID4) / 4];
+        break;
+
+    case A_CPU0INTR_SET:
+    case A_CPU0INTR_CLR:
+    case A_CPU1INTR_SET:
+    case A_CPU1INTR_CLR:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "SSE MHU: read of write-only register at offset 0x%x\n",
+                      (int)offset);
+        r = 0;
+        break;
+
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "SSE MHU read: bad offset 0x%x\n", (int)offset);
+        r = 0;
+        break;
+    }
+    trace_armsse_mhu_read(offset, r, size);
+    return r;
+}
+
+static void armsse_mhu_write(void *opaque, hwaddr offset,
+                             uint64_t value, unsigned size)
+{
+    ARMSSEMHU *s = ARMSSE_MHU(opaque);
+
+    trace_armsse_mhu_write(offset, value, size);
+
+    switch (offset) {
+    case A_CPU0INTR_SET:
+        s->cpu0intr |= (value & INTR_MASK);
+        break;
+    case A_CPU0INTR_CLR:
+        s->cpu0intr &= ~(value & INTR_MASK);
+        break;
+    case A_CPU1INTR_SET:
+        s->cpu1intr |= (value & INTR_MASK);
+        break;
+    case A_CPU1INTR_CLR:
+        s->cpu1intr &= ~(value & INTR_MASK);
+        break;
+
+    case A_CPU0INTR_STAT:
+    case A_CPU1INTR_STAT:
+    case A_PID4 ... A_CID3:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "SSE MHU: write to read-only register at offset 0x%x\n",
+                      (int)offset);
+        break;
+
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "SSE MHU write: bad offset 0x%x\n", (int)offset);
+        break;
+    }
+
+    armsse_mhu_update(s);
+}
+
+static const MemoryRegionOps armsse_mhu_ops = {
+    .read = armsse_mhu_read,
+    .write = armsse_mhu_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid.min_access_size = 4,
+    .valid.max_access_size = 4,
+};
+
+static void armsse_mhu_reset(DeviceState *dev)
+{
+    ARMSSEMHU *s = ARMSSE_MHU(dev);
+
+    s->cpu0intr = 0;
+    s->cpu1intr = 0;
+}
+
+static const VMStateDescription armsse_mhu_vmstate = {
+    .name = "armsse-mhu",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(cpu0intr, ARMSSEMHU),
+        VMSTATE_UINT32(cpu1intr, ARMSSEMHU),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
+static void armsse_mhu_init(Object *obj)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    ARMSSEMHU *s = ARMSSE_MHU(obj);
+
+    memory_region_init_io(&s->iomem, obj, &armsse_mhu_ops,
+                          s, "armsse-mhu", 0x1000);
+    sysbus_init_mmio(sbd, &s->iomem);
+    sysbus_init_irq(sbd, &s->cpu0irq);
+    sysbus_init_irq(sbd, &s->cpu1irq);
+}
+
+static void armsse_mhu_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->reset = armsse_mhu_reset;
+    dc->vmsd = &armsse_mhu_vmstate;
+}
+
+static const TypeInfo armsse_mhu_info = {
+    .name = TYPE_ARMSSE_MHU,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(ARMSSEMHU),
+    .instance_init = armsse_mhu_init,
+    .class_init = armsse_mhu_class_init,
+};
+
+static void armsse_mhu_register_types(void)
+{
+    type_register_static(&armsse_mhu_info);
+}
+
+type_init(armsse_mhu_register_types);
diff --git a/hw/misc/trace-events b/hw/misc/trace-events
index b0701bddd3..c1795bb54b 100644
--- a/hw/misc/trace-events
+++ b/hw/misc/trace-events
@@ -136,3 +136,7 @@ iotkit_sysctl_reset(void) "IoTKit SysCtl: reset"
 # hw/misc/armsse-cpuid.c
 armsse_cpuid_read(uint64_t offset, uint64_t data, unsigned size) "SSE-200 CPU_IDENTITY read: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
 armsse_cpuid_write(uint64_t offset, uint64_t data, unsigned size) "SSE-200 CPU_IDENTITY write: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
+
+# hw/misc/armsse-mhu.c
+armsse_mhu_read(uint64_t offset, uint64_t data, unsigned size) "SSE-200 MHU read: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
+armsse_mhu_write(uint64_t offset, uint64_t data, unsigned size) "SSE-200 MHU write: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"