ide: add IDE_HFLAG_SERIALIZE_DMA host flag

* Add IDE_HFLAG_SERIALIZE_DMA host flag to serialize ports
  if DMA is available and handle it in ide_init_port().

* Convert sl82c105 host driver to use this new flag.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

3 files changed, 9 insertions, 5 deletions

diff --git a/drivers/ide/ide-probe.c b/drivers/ide/ide-probe.c
index e0316869eb6f..b58eb792172e 100644
--- a/drivers/ide/ide-probe.c
+++ b/drivers/ide/ide-probe.c
@@ -1367,8 +1367,11 @@ static void ide_init_port(ide_hwif_t *hwif, unsigned int port,
         if (hwif->chipset != ide_dtc2278 || hwif->channel == 0)
                 hwif->port_ops = d->port_ops;
 
-        if ((d->host_flags & IDE_HFLAG_SERIALIZE) && hwif->mate)
-                hwif->mate->serialized = hwif->serialized = 1;
+        if ((d->host_flags & IDE_HFLAG_SERIALIZE) ||
+            ((d->host_flags & IDE_HFLAG_SERIALIZE_DMA) && hwif->dma_base)) {
+                if (hwif->mate)
+                        hwif->mate->serialized = hwif->serialized = 1;
+        }
 
         hwif->swdma_mask = d->swdma_mask;
         hwif->mwdma_mask = d->mwdma_mask;
diff --git a/drivers/ide/pci/sl82c105.c b/drivers/ide/pci/sl82c105.c
index 2c2fe59a0d9e..c2127cbdecd3 100644
--- a/drivers/ide/pci/sl82c105.c
+++ b/drivers/ide/pci/sl82c105.c
@@ -296,9 +296,6 @@ static void __devinit init_hwif_sl82c105(ide_hwif_t *hwif)
         hwif->dma_start                 = &sl82c105_dma_start;
         hwif->ide_dma_end               = &sl82c105_dma_end;
         hwif->dma_timeout               = &sl82c105_dma_timeout;
-
-        if (hwif->mate)
-                hwif->serialized = hwif->mate->serialized = 1;
 }
 
 static const struct ide_port_ops sl82c105_port_ops = {
@@ -319,6 +316,7 @@ static const struct ide_port_info sl82c105_chipset __devinitdata = {
 #if defined(CONFIG_LOPEC) || defined(CONFIG_SANDPOINT)
                           IDE_HFLAG_FORCE_LEGACY_IRQS |
 #endif
+                          IDE_HFLAG_SERIALIZE_DMA |
                           IDE_HFLAG_NO_AUTODMA,
         .pio_mask       = ATA_PIO5,
         .mwdma_mask     = ATA_MWDMA2,
@@ -338,6 +336,7 @@ static int __devinit sl82c105_init_one(struct pci_dev *dev, const struct pci_dev
                                  "revision %d, BM-DMA disabled\n", rev);
                 d.init_hwif = NULL;
                 d.mwdma_mask = 0;
+                d.host_flags &= ~IDE_HFLAG_SERIALIZE_DMA;
         }
 
         return ide_setup_pci_device(dev, &d);
diff --git a/include/linux/ide.h b/include/linux/ide.h
index 2da46af64604..e5f41741ba91 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -1087,6 +1087,8 @@ enum {
         /* unmask IRQs */
         IDE_HFLAG_UNMASK_IRQS           = (1 << 25),
         IDE_HFLAG_ABUSE_SET_DMA_MODE    = (1 << 26),
+        /* serialize ports if DMA is possible (for sl82c105) */
+        IDE_HFLAG_SERIALIZE_DMA         = (1 << 27),
         /* force host out of "simplex" mode */
         IDE_HFLAG_CLEAR_SIMPLEX         = (1 << 28),
         /* DSC overlap is unsupported */