diff --git a/devices/common/dmacore.h b/devices/common/dmacore.h
index 72bedb8..5737cd2 100644
--- a/devices/common/dmacore.h
+++ b/devices/common/dmacore.h
@@ -33,7 +33,16 @@ enum DmaPullResult : int {
 
 class DmaOutChannel {
 public:
-    virtual bool            is_active() = 0;
+    virtual bool            is_active() { return true; };
+    virtual DmaPullResult   pull_data(uint32_t req_len, uint32_t *avail_len,
+                                      uint8_t **p_data) = 0;
+};
+
+// Base class for bidirectional DMA channels.
+class DmaBidirChannel {
+public:
+    virtual bool            is_active() { return true; };
+    virtual int             push_data(const char* src_ptr, int len) = 0;
     virtual DmaPullResult   pull_data(uint32_t req_len, uint32_t *avail_len,
                                       uint8_t **p_data) = 0;
 };
diff --git a/devices/floppy/swim3.h b/devices/floppy/swim3.h
index 2b5a154..05acf8e 100644
--- a/devices/floppy/swim3.h
+++ b/devices/floppy/swim3.h
@@ -24,6 +24,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #ifndef SWIM3_H
 #define SWIM3_H
 
+#include <devices/common/dmacore.h>
 #include <devices/common/hwcomponent.h>
 #include <devices/common/hwinterrupt.h>
 #include <devices/floppy/superdrive.h>
@@ -78,6 +79,10 @@ public:
     uint8_t read(uint8_t reg_offset);
     void    write(uint8_t reg_offset, uint8_t value);
 
+    void set_dma_channel(DmaBidirChannel *dma_ch) {
+        this->dma_ch = dma_ch;
+    };
+
 protected:
     void update_irq();
     void start_stepping();
@@ -89,6 +94,8 @@ protected:
 private:
     std::unique_ptr<MacSuperdrive::MacSuperDrive> int_drive;
 
+    DmaBidirChannel*    dma_ch;
+
     uint8_t setup_reg;
     uint8_t mode_reg;
     uint8_t error;