// address.
 // A write transaction to clear registered higher 4 bytes of destination address
 // has an effect to suppress asynchronous transaction from device.
-static void ff800_handle_midi_msg(struct snd_ff *ff, unsigned int offset,
-                                 __le32 *buf, size_t length)
+static void ff800_handle_midi_msg(struct snd_ff *ff, unsigned int offset, const __le32 *buf,
+                                 size_t length)
 {
        int i;
 
 }
 
 const struct snd_ff_protocol snd_ff_protocol_ff800 = {
-       .handle_midi_msg        = ff800_handle_midi_msg,
+       .handle_msg             = ff800_handle_midi_msg,
        .fill_midi_msg          = former_fill_midi_msg,
        .get_clock              = former_get_clock,
        .switch_fetching_mode   = former_switch_fetching_mode,
 // input attenuation. This driver allocates destination address with '0000'0000
 // in its lower offset and expects userspace application to configure the
 // register for it.
-static void ff400_handle_midi_msg(struct snd_ff *ff, unsigned int offset,
-                                 __le32 *buf, size_t length)
+static void ff400_handle_msg(struct snd_ff *ff, unsigned int offset, const __le32 *buf,
+                            size_t length)
 {
        int i;
 
 }
 
 const struct snd_ff_protocol snd_ff_protocol_ff400 = {
-       .handle_midi_msg        = ff400_handle_midi_msg,
+       .handle_msg             = ff400_handle_msg,
        .fill_midi_msg          = former_fill_midi_msg,
        .get_clock              = former_get_clock,
        .switch_fetching_mode   = former_switch_fetching_mode,
 
 // input attenuation. This driver allocates for the first option
 // (0x'....'....'0000'0000) and expects userspace application to configure the
 // register for it.
-static void latter_handle_midi_msg(struct snd_ff *ff, unsigned int offset,
-                                  __le32 *buf, size_t length)
+static void latter_handle_midi_msg(struct snd_ff *ff, unsigned int offset, const __le32 *buf,
+                                  size_t length)
 {
        u32 data = le32_to_cpu(*buf);
        unsigned int index = (data & 0x000000f0) >> 4;
 }
 
 const struct snd_ff_protocol snd_ff_protocol_latter = {
-       .handle_midi_msg        = latter_handle_midi_msg,
+       .handle_msg             = latter_handle_midi_msg,
        .fill_midi_msg          = latter_fill_midi_msg,
        .get_clock              = latter_get_clock,
        .switch_fetching_mode   = latter_switch_fetching_mode,
 
        transmit_midi_msg(ff, 1);
 }
 
-static void handle_midi_msg(struct fw_card *card, struct fw_request *request,
-                           int tcode, int destination, int source,
-                           int generation, unsigned long long offset,
-                           void *data, size_t length, void *callback_data)
+static void handle_msg(struct fw_card *card, struct fw_request *request, int tcode,
+                      int destination, int source, int generation, unsigned long long offset,
+                      void *data, size_t length, void *callback_data)
 {
        struct snd_ff *ff = callback_data;
        __le32 *buf = data;
        fw_send_response(card, request, RCODE_COMPLETE);
 
        offset -= ff->async_handler.offset;
-       ff->spec->protocol->handle_midi_msg(ff, (unsigned int)offset, buf,
-                                           length);
+       ff->spec->protocol->handle_msg(ff, (unsigned int)offset, buf, length);
 }
 
 static int allocate_own_address(struct snd_ff *ff, int i)
        int err;
 
        ff->async_handler.length = ff->spec->midi_addr_range;
-       ff->async_handler.address_callback = handle_midi_msg;
+       ff->async_handler.address_callback = handle_msg;
        ff->async_handler.callback_data = ff;
 
        midi_msg_region.start = 0x000100000000ull * i;
 
 };
 
 struct snd_ff_protocol {
-       void (*handle_midi_msg)(struct snd_ff *ff, unsigned int offset,
-                               __le32 *buf, size_t length);
+       void (*handle_msg)(struct snd_ff *ff, unsigned int offset, const __le32 *buf,
+                          size_t length);
        int (*fill_midi_msg)(struct snd_ff *ff,
                             struct snd_rawmidi_substream *substream,
                             unsigned int port);