libata: implement per-dev xfer masks, take#2

index f3c115b..1514cb5 100644
@@ -252,6 +252,29 @@ static unsigned int ata_pack_xfermask(un
 		((udma_mask << ATA_SHIFT_UDMA) & ATA_MASK_UDMA);
 }
 
+/**
+ *	ata_unpack_xfermask - Unpack xfer_mask into pio, mwdma and udma masks
+ *	@xfer_mask: xfer_mask to unpack
+ *	@pio_mask: resulting pio_mask
+ *	@mwdma_mask: resulting mwdma_mask
+ *	@udma_mask: resulting udma_mask
+ *
+ *	Unpack @xfer_mask into @pio_mask, @mwdma_mask and @udma_mask.
+ *	Any NULL distination masks will be ignored.
+ */
+static void ata_unpack_xfermask(unsigned int xfer_mask,
+				unsigned int *pio_mask,
+				unsigned int *mwdma_mask,
+				unsigned int *udma_mask)
+{
+	if (pio_mask)
+		*pio_mask = (xfer_mask & ATA_MASK_PIO) >> ATA_SHIFT_PIO;
+	if (mwdma_mask)
+		*mwdma_mask = (xfer_mask & ATA_MASK_MWDMA) >> ATA_SHIFT_MWDMA;
+	if (udma_mask)
+		*udma_mask = (xfer_mask & ATA_MASK_UDMA) >> ATA_SHIFT_UDMA;
+}
+
 static const struct ata_xfer_ent {
 	unsigned int shift, bits;
 	u8 base;

index 1514cb5..a87748b 100644
@@ -65,8 +65,7 @@ static unsigned int ata_dev_init_params(
 					struct ata_device *dev);
 static void ata_set_mode(struct ata_port *ap);
 static void ata_dev_set_xfermode(struct ata_port *ap, struct ata_device *dev);
-static unsigned int ata_dev_xfermask(struct ata_port *ap,
-				     struct ata_device *dev);
+static void ata_dev_xfermask(struct ata_port *ap, struct ata_device *dev);
 
 static unsigned int ata_unique_id = 1;
 static struct workqueue_struct *ata_wq;

@@ -1801,16 +1800,19 @@ static void ata_set_mode(struct ata_port
 	/* step 1: calculate xfer_mask */
 	for (i = 0; i < ATA_MAX_DEVICES; i++) {
 		struct ata_device *dev = &ap->device[i];
-		unsigned int xfer_mask;
+		unsigned int pio_mask, dma_mask;
 
 		if (!ata_dev_present(dev))
 			continue;
 
-		xfer_mask = ata_dev_xfermask(ap, dev);
+		ata_dev_xfermask(ap, dev);
 
-		dev->pio_mode = ata_xfer_mask2mode(xfer_mask & ATA_MASK_PIO);
-		dev->dma_mode = ata_xfer_mask2mode(xfer_mask & (ATA_MASK_MWDMA |
-								ATA_MASK_UDMA));
+		/* TODO: let LLDD filter dev->*_mask here */
+
+		pio_mask = ata_pack_xfermask(dev->pio_mask, 0, 0);
+		dma_mask = ata_pack_xfermask(0, dev->mwdma_mask, dev->udma_mask);
+		dev->pio_mode = ata_xfer_mask2mode(pio_mask);
+		dev->dma_mode = ata_xfer_mask2mode(dma_mask);
 	}
 
 	/* step 2: always set host PIO timings */

@@ -2653,18 +2655,15 @@ static int ata_dma_blacklisted(const str
  *	@ap: Port on which the device to compute xfermask for resides
  *	@dev: Device to compute xfermask for
  *
- *	Compute supported xfermask of @dev.  This function is
- *	responsible for applying all known limits including host
- *	controller limits, device blacklist, etc...
+ *	Compute supported xfermask of @dev and store it in
+ *	dev->*_mask.  This function is responsible for applying all
+ *	known limits including host controller limits, device
+ *	blacklist, etc...
  *
  *	LOCKING:
  *	None.
- *
- *	RETURNS:
- *	Computed xfermask.
  */
-static unsigned int ata_dev_xfermask(struct ata_port *ap,
-				     struct ata_device *dev)
+static void ata_dev_xfermask(struct ata_port *ap, struct ata_device *dev)
 {
 	unsigned long xfer_mask;
 	int i;

@@ -2677,6 +2676,8 @@ static unsigned int ata_dev_xfermask(str
 		struct ata_device *d = &ap->device[i];
 		if (!ata_dev_present(d))
 			continue;
+		xfer_mask &= ata_pack_xfermask(d->pio_mask, d->mwdma_mask,
+					       d->udma_mask);
 		xfer_mask &= ata_id_xfermask(d->id);
 		if (ata_dma_blacklisted(d))
 			xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA);

@@ -2686,7 +2687,8 @@ static unsigned int ata_dev_xfermask(str
 		printk(KERN_WARNING "ata%u: dev %u is on DMA blacklist, "
 		       "disabling DMA\n", ap->id, dev->devno);
 
-	return xfer_mask;
+	ata_unpack_xfermask(xfer_mask, &dev->pio_mask, &dev->mwdma_mask,
+			    &dev->udma_mask);
 }
 
 /**

@@ -4436,8 +4438,13 @@ static void ata_host_init(struct ata_por
 	INIT_WORK(&ap->port_task, NULL, NULL);
 	INIT_LIST_HEAD(&ap->eh_done_q);
 
-	for (i = 0; i < ATA_MAX_DEVICES; i++)
-		ap->device[i].devno = i;
+	for (i = 0; i < ATA_MAX_DEVICES; i++) {
+		struct ata_device *dev = &ap->device[i];
+		dev->devno = i;
+		dev->pio_mask = UINT_MAX;
+		dev->mwdma_mask = UINT_MAX;
+		dev->udma_mask = UINT_MAX;
+	}
 
 #ifdef ATA_IRQ_TRAP
 	ap->stats.unhandled_irq = 1;

index 7a54244..fbe8ba2 100644
@@ -358,6 +358,11 @@ struct ata_device {
 	unsigned int		max_sectors;	/* per-device max sectors */
 	unsigned int		cdb_len;
 
+	/* per-dev xfer mask */
+	unsigned int		pio_mask;
+	unsigned int		mwdma_mask;
+	unsigned int		udma_mask;
+
 	/* for CHS addressing */
 	u16			cylinders;	/* Number of cylinders */
 	u16			heads;		/* Number of heads */

index 0aff888..e4bd673 100644
@@ -2634,6 +2634,10 @@ static int ata_dma_blacklisted(const str
  *	known limits including host controller limits, device
  *	blacklist, etc...
  *
+ *	FIXME: The current implementation limits all transfer modes to
+ *	the fastest of the lowested device on the port.  This is not
+ *	required on most controllers. 
+ *
  *	LOCKING:
  *	None.
  */

index 1cb9813..8631056 100644
@@ -2635,7 +2635,7 @@ static int ata_dma_blacklisted(const str
  *
  *	FIXME: The current implementation limits all transfer modes to
  *	the fastest of the lowested device on the port.  This is not
- *	required on most controllers. 
+ *	required on most controllers.
  *
  *	LOCKING:
  *	None.

index a87748b..1063928 100644
@@ -1327,7 +1327,7 @@ static int ata_dev_configure(struct ata_
 		if (print_info)
 			printk(KERN_INFO "ata%u(%u): applying bridge limits\n",
 			       ap->id, dev->devno);
-		ap->udma_mask &= ATA_UDMA5;
+		dev->udma_mask &= ATA_UDMA5;
 		dev->max_sectors = ATA_MAX_SECTORS;
 	}
 

index 3e75d67..18c296c 100644
@@ -371,7 +371,7 @@ static void sil_dev_config(struct ata_po
 	if (quirks & SIL_QUIRK_UDMA5MAX) {
 		printk(KERN_INFO "ata%u(%u): applying Maxtor errata fix %s\n",
 		       ap->id, dev->devno, model_num);
-		ap->udma_mask &= ATA_UDMA5;
+		dev->udma_mask &= ATA_UDMA5;
 		return;
 	}
 }