ata: Fix bus master direction flag

! ata: Bit 3 in the Bus Master IDE Command Register is set if the DMA
  transfer is a bus master write, i.e. read from disk and write to
  memory. Current code got that wrong and sets it for writes to the
  disk.
Signed-off-by: Kevin Wolf <kevin@tyndur.org>

ata/device.h

@@ -116,7 +116,7 @@
 
 // Bits im Busmaster Command Register
 #define BMR_CMD_START           (1 << 0)
-#define BMR_CMD_WRITE           (1 << 3)
+#define BMR_CMD_READ            (1 << 3)
 
 // Bits im Busmaster Status Register
 #define BMR_STATUS_ERROR        (1 << 1)

ata/request.c

@@ -461,10 +461,11 @@ static int ata_protocol_dma(struct ata_request* request)
     // aus, dass es notwendig ist.
     cdi_inb(ctrl->port_bmr_base + BMR_COMMAND);
     cdi_inb(ctrl->port_bmr_base + BMR_STATUS);
+
     // Busmastering starten
-    if (request->flags.direction != READ) {
-        cdi_outb(ctrl->port_bmr_base + BMR_COMMAND, BMR_CMD_START |
-            BMR_CMD_WRITE);
+    if (request->flags.direction == READ) {
+        cdi_outb(ctrl->port_bmr_base + BMR_COMMAND,
+            BMR_CMD_START | BMR_CMD_READ);
     } else {
         cdi_outb(ctrl->port_bmr_base + BMR_COMMAND, BMR_CMD_START);
     }