2 files changed, 78 insertions, 2 deletions

diff --git a/hw/fsi/lbus.c b/hw/fsi/lbus.c
index 44d2319087..20495f42fd 100644
--- a/hw/fsi/lbus.c
+++ b/hw/fsi/lbus.c
@@ -8,11 +8,12 @@
 #include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "hw/fsi/lbus.h"
-
 #include "hw/qdev-properties.h"
-
+#include "qemu/log.h"
 #include "trace.h"
 
+#define TO_REG(offset) ((offset) >> 2)
+
 static void fsi_lbus_init(Object *o)
 {
     FSILBus *lbus = FSI_LBUS(o);
@@ -34,10 +35,83 @@ static const TypeInfo fsi_lbus_device_type_info = {
     .abstract = true,
 };
 
+static uint64_t fsi_scratchpad_read(void *opaque, hwaddr addr, unsigned size)
+{
+    FSIScratchPad *s = SCRATCHPAD(opaque);
+    int reg = TO_REG(addr);
+
+    trace_fsi_scratchpad_read(addr, size);
+
+    if (reg >= FSI_SCRATCHPAD_NR_REGS) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Out-of-bounds read at offset 0x%" HWADDR_PRIx "\n",
+                      __func__, addr);
+        return 0;
+    }
+
+    return s->regs[reg];
+}
+
+static void fsi_scratchpad_write(void *opaque, hwaddr addr, uint64_t data,
+                                 unsigned size)
+{
+    FSIScratchPad *s = SCRATCHPAD(opaque);
+
+    trace_fsi_scratchpad_write(addr, size, data);
+    int reg = TO_REG(addr);
+
+    if (reg >= FSI_SCRATCHPAD_NR_REGS) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Out-of-bounds write at offset 0x%" HWADDR_PRIx "\n",
+                      __func__, addr);
+        return;
+    }
+
+    s->regs[reg] = data;
+}
+
+static const struct MemoryRegionOps scratchpad_ops = {
+    .read = fsi_scratchpad_read,
+    .write = fsi_scratchpad_write,
+    .endianness = DEVICE_BIG_ENDIAN,
+};
+
+static void fsi_scratchpad_realize(DeviceState *dev, Error **errp)
+{
+    FSILBusDevice *ldev = FSI_LBUS_DEVICE(dev);
+
+    memory_region_init_io(&ldev->iomem, OBJECT(ldev), &scratchpad_ops,
+                          ldev, TYPE_FSI_SCRATCHPAD, 0x400);
+}
+
+static void fsi_scratchpad_reset(DeviceState *dev)
+{
+    FSIScratchPad *s = SCRATCHPAD(dev);
+
+    memset(s->regs, 0, sizeof(s->regs));
+}
+
+static void fsi_scratchpad_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->bus_type = TYPE_FSI_LBUS;
+    dc->realize = fsi_scratchpad_realize;
+    dc->reset = fsi_scratchpad_reset;
+}
+
+static const TypeInfo fsi_scratchpad_info = {
+    .name = TYPE_FSI_SCRATCHPAD,
+    .parent = TYPE_FSI_LBUS_DEVICE,
+    .instance_size = sizeof(FSIScratchPad),
+    .class_init = fsi_scratchpad_class_init,
+};
+
 static void fsi_lbus_register_types(void)
 {
     type_register_static(&fsi_lbus_info);
     type_register_static(&fsi_lbus_device_type_info);
+    type_register_static(&fsi_scratchpad_info);
 }
 
 type_init(fsi_lbus_register_types);
diff --git a/hw/fsi/trace-events b/hw/fsi/trace-events
index e69de29bb2..c5753e2791 100644
--- a/hw/fsi/trace-events
+++ b/hw/fsi/trace-events
@@ -0,0 +1,2 @@
+fsi_scratchpad_read(uint64_t addr, uint32_t size) "@0x%" PRIx64 " size=%d"
+fsi_scratchpad_write(uint64_t addr, uint32_t size, uint64_t data) "@0x%" PRIx64 " size=%d value=0x%"PRIx64