diff --git a/hiomap.cpp b/hiomap.cpp
new file mode 100644
index 0000000..f623e61
--- /dev/null
+++ b/hiomap.cpp
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright (C) 2018 IBM Corp.
+
+#include "config.h"
+
+#include "hiomap.hpp"
+
+#include <endian.h>
+#include <host-ipmid/ipmid-api.h>
+#include <string.h>
+#include <systemd/sd-bus.h>
+
+#include <fstream>
+#include <sdbusplus/bus.hpp>
+#include <sdbusplus/exception.hpp>
+
+using namespace sdbusplus;
+
+static void register_openpower_hiomap_commands() __attribute__((constructor));
+
+namespace openpower
+{
+namespace flash
+{
+
+/* TODO: Replace get/put with packed structs and direct assignment */
+template <typename T> static inline T get(void *buf)
+{
+    T t;
+    memcpy(&t, buf, sizeof(t));
+    return t;
+}
+
+template <typename T> static inline void put(void *buf, T &&t)
+{
+    memcpy(buf, &t, sizeof(t));
+}
+
+typedef ipmi_ret_t (*hiomap_command)(ipmi_request_t req, ipmi_response_t resp,
+                                     ipmi_data_len_t data_len,
+                                     ipmi_context_t context);
+
+struct errno_cc_entry
+{
+    int err;
+    int cc;
+};
+
+static const errno_cc_entry errno_cc_map[] = {
+    {0, IPMI_CC_OK},
+    {EBUSY, IPMI_CC_BUSY},
+    {ENOTSUP, IPMI_CC_INVALID},
+    {ETIMEDOUT, 0xc3}, /* FIXME: Replace when defined in ipmid-api.h */
+    {ENOSPC, 0xc4},    /* FIXME: Replace when defined in ipmid-api.h */
+    {EINVAL, IPMI_CC_PARM_OUT_OF_RANGE},
+    {ENODEV, IPMI_CC_SENSOR_INVALID},
+    {EPERM, IPMI_CC_INSUFFICIENT_PRIVILEGE},
+    {EACCES, IPMI_CC_INSUFFICIENT_PRIVILEGE},
+    {-1, IPMI_CC_UNSPECIFIED_ERROR},
+};
+
+static int hiomap_xlate_errno(int err)
+{
+    const errno_cc_entry *entry = &errno_cc_map[0];
+
+    while (!(entry->err == err || entry->err == -1))
+    {
+        entry++;
+    }
+
+    return entry->cc;
+}
+
+static ipmi_ret_t hiomap_get_info(ipmi_request_t request,
+                                  ipmi_response_t response,
+                                  ipmi_data_len_t data_len,
+                                  ipmi_context_t context)
+{
+    if (*data_len < 1)
+    {
+        return IPMI_CC_REQ_DATA_LEN_INVALID;
+    }
+
+    uint8_t *reqdata = (uint8_t *)request;
+    auto b = bus::new_system();
+    auto m = b.new_method_call(
+        "xyz.openbmc_project.Hiomapd", "/xyz/openbmc_project/Hiomapd",
+        "xyz.openbmc_project.Hiomapd.Protocol", "GetInfo");
+    m.append(reqdata[0]);
+
+    try
+    {
+        auto reply = b.call(m);
+
+        uint8_t version;
+        uint8_t blockSizeShift;
+        uint16_t timeout;
+        reply.read(version, blockSizeShift, timeout);
+
+        uint8_t *respdata = (uint8_t *)response;
+
+        /* FIXME: Assumes v2! */
+        put(&respdata[0], version);
+        put(&respdata[1], blockSizeShift);
+        put(&respdata[2], htole16(timeout));
+
+        *data_len = 4;
+    }
+    catch (const exception::SdBusError &e)
+    {
+        return hiomap_xlate_errno(e.get_errno());
+    }
+
+    return IPMI_CC_OK;
+}
+
+static const hiomap_command hiomap_commands[] = {
+    [0] = NULL, /* 0 is an invalid command ID */
+    [1] = NULL, /* RESET */
+    [2] = hiomap_get_info,
+};
+
+/* FIXME: Define this in the "right" place, wherever that is */
+/* FIXME: Double evaluation */
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+static ipmi_ret_t hiomap_dispatch(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
+                                  ipmi_request_t request,
+                                  ipmi_response_t response,
+                                  ipmi_data_len_t data_len,
+                                  ipmi_context_t context)
+{
+    if (*data_len < 2)
+    {
+        *data_len = 0;
+        return IPMI_CC_REQ_DATA_LEN_INVALID;
+    }
+
+    uint8_t *ipmi_req = (uint8_t *)request;
+    uint8_t *ipmi_resp = (uint8_t *)response;
+    uint8_t hiomap_cmd = ipmi_req[0];
+
+    if (hiomap_cmd == 0 || hiomap_cmd > ARRAY_SIZE(hiomap_commands) - 1)
+    {
+        *data_len = 0;
+        return IPMI_CC_PARM_OUT_OF_RANGE;
+    }
+    uint8_t *flash_req = ipmi_req + 2;
+    size_t flash_len = *data_len - 2;
+    uint8_t *flash_resp = ipmi_resp + 2;
+
+    ipmi_ret_t cc =
+        hiomap_commands[hiomap_cmd](flash_req, flash_resp, &flash_len, context);
+    if (cc != IPMI_CC_OK)
+    {
+        *data_len = 0;
+        return cc;
+    }
+
+    /* Populate the response command and sequence */
+    put(&ipmi_resp[0], ipmi_req[0]);
+    put(&ipmi_resp[1], ipmi_req[1]);
+
+    *data_len = flash_len + 2;
+
+    return cc;
+}
+} // namespace flash
+} // namespace openpower
+
+static void register_openpower_hiomap_commands()
+{
+    ipmi_register_callback(NETFUN_IBM_OEM, IPMI_CMD_HIOMAP, NULL,
+                           openpower::flash::hiomap_dispatch, SYSTEM_INTERFACE);
+}