I/OAT: Add support for version 2 of ioatdma device

Add support for version 2 of the ioatdma device.  This device handles
the descriptor chain and DCA services slightly differently:
 - Instead of moving the dma descriptors between a busy and an idle chain,
   this new version uses a single circular chain so that we don't have
   rewrite the next_descriptor pointers as we add new requests, and the
   device doesn't need to re-read the last descriptor.
 - The new device has the DCA tags defined internally instead of needing
   them defined statically.

Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Cc: "Williams, Dan J" <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/dma/ioat.c b/drivers/dma/ioat.c
index f204c39..16e0fd8 100644
--- a/drivers/dma/ioat.c
+++ b/drivers/dma/ioat.c
@@ -39,10 +39,14 @@
 MODULE_AUTHOR("Intel Corporation");
 
 static struct pci_device_id ioat_pci_tbl[] = {
+	/* I/OAT v1 platforms */
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_CNB)  },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_SCNB) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_UNISYS, PCI_DEVICE_ID_UNISYS_DMA_DIRECTOR) },
+
+	/* I/OAT v2 platforms */
+	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_SNB) },
 	{ 0, }
 };
 
@@ -74,10 +78,17 @@
 		if (device->dma && ioat_dca_enabled)
 			device->dca = ioat_dca_init(pdev, iobase);
 		break;
+	case IOAT_VER_2_0:
+		device->dma = ioat_dma_probe(pdev, iobase);
+		if (device->dma && ioat_dca_enabled)
+			device->dca = ioat2_dca_init(pdev, iobase);
+		break;
 	default:
 		err = -ENODEV;
 		break;
 	}
+	if (!device->dma)
+		err = -ENODEV;
 	return err;
 }