PPC: dbdma: Wait for DMA until we have data We should only start processing DMA requests when we have data to process. Hold off working through the DMA shuffling until the IDE core told us that it's ready. This is required because the guest can program the DMA engine or the IDE transfer first. Both are legal. Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/hw/ide/macio.c b/hw/ide/macio.c
index 126549d..2b1e51d 100644
--- a/hw/ide/macio.c
+++ b/hw/ide/macio.c

@@ -64,6 +64,14 @@
         goto done;
     }
 
+    if (!m->dma_active) {
+        MACIO_DPRINTF("waiting for data (%#x - %#x - %x)\n",
+                      s->nsector, io->len, s->status);
+        /* data not ready yet, wait for the channel to get restarted */
+        io->processing = false;
+        return;
+    }
+
     MACIO_DPRINTF("io_buffer_size = %#x\n", s->io_buffer_size);
 
     if (s->io_buffer_size > 0) {
@@ -80,6 +88,7 @@
     if (s->packet_transfer_size <= 0) {
         MACIO_DPRINTF("end of transfer\n");
         ide_atapi_cmd_ok(s);
+        m->dma_active = false;
     }
 
     if (io->len == 0) {
@@ -130,6 +139,14 @@
         goto done;
     }
 
+    if (!m->dma_active) {
+        MACIO_DPRINTF("waiting for data (%#x - %#x - %x)\n",
+                      s->nsector, io->len, s->status);
+        /* data not ready yet, wait for the channel to get restarted */
+        io->processing = false;
+        return;
+    }
+
     sector_num = ide_get_sector(s);
     MACIO_DPRINTF("io_buffer_size = %#x\n", s->io_buffer_size);
     if (s->io_buffer_size > 0) {
@@ -145,6 +162,7 @@
         MACIO_DPRINTF("end of transfer\n");
         s->status = READY_STAT | SEEK_STAT;
         ide_set_irq(s->bus);
+        m->dma_active = false;
     }
 
     if (io->len == 0) {
@@ -379,6 +397,7 @@
     MACIOIDEState *m = container_of(dma, MACIOIDEState, dma);
 
     MACIO_DPRINTF("\n");
+    m->dma_active = true;
     DBDMA_kick(m->dbdma);
 }
 

diff --git a/hw/ppc/mac.h b/hw/ppc/mac.h
index 27c4ca3..1e578dd 100644
--- a/hw/ppc/mac.h
+++ b/hw/ppc/mac.h

@@ -133,6 +133,7 @@
     BlockDriverAIOCB *aiocb;
     IDEDMA dma;
     void *dbdma;
+    bool dma_active;
 } MACIOIDEState;
 
 void macio_ide_init_drives(MACIOIDEState *ide, DriveInfo **hd_table);