[SCSI] megaraid_{mm,mbox}: 64-bit DMA capability checker

This patch contains
- a fix for 64-bit DMA capability check in megaraid_{mm,mbox} driver.
- includes changes (going back to 32-bit DMA mask if 64-bit DMA mask
failes) suggested by James with previous patch.
- addition of SATA 150-4/6 as commented by Vasily Averin.

With patch, the driver access PCIconfiguration space with dedicated
offset to read a signature. If the signature read, it means that the
controller has capability to handle 64-bit DMA.
Without this patch, the driver used to blindly claim 64-bit DMA
capability.
The issue has been reported by Vasily Averin [vvs@sw.ru].
Thank you Vasily for the reporting.

Signed-Off By: Seokmann Ju <seokmann.ju@lsil.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 28 insertions, 6 deletions

diff --git a/drivers/scsi/megaraid/megaraid_mbox.c b/drivers/scsi/megaraid/megaraid_mbox.c
index 92715130ac09..e671af0b4f58 100644
--- a/drivers/scsi/megaraid/megaraid_mbox.c
+++ b/drivers/scsi/megaraid/megaraid_mbox.c
@@ -10,7 +10,7 @@
  *	   2 of the License, or (at your option) any later version.
  *
  * FILE		: megaraid_mbox.c
- * Version	: v2.20.4.8 (Apr 11 2006)
+ * Version	: v2.20.4.9 (Jul 16 2006)
  *
  * Authors:
  * 	Atul Mukker		<Atul.Mukker@lsil.com>
@@ -720,6 +720,7 @@ megaraid_init_mbox(adapter_t *adapter)
 	struct pci_dev		*pdev;
 	mraid_device_t		*raid_dev;
 	int			i;
+	uint32_t		magic64;
 
 
 	adapter->ito	= MBOX_TIMEOUT;
@@ -863,12 +864,33 @@ megaraid_init_mbox(adapter_t *adapter)
 
 	// Set the DMA mask to 64-bit. All supported controllers as capable of
 	// DMA in this range
-	if (pci_set_dma_mask(adapter->pdev, DMA_64BIT_MASK) != 0) {
-
-		con_log(CL_ANN, (KERN_WARNING
-			"megaraid: could not set DMA mask for 64-bit.\n"));
+	pci_read_config_dword(adapter->pdev, PCI_CONF_AMISIG64, &magic64);
+
+	if (((magic64 == HBA_SIGNATURE_64_BIT) &&
+		((adapter->pdev->subsystem_device !=
+		PCI_SUBSYS_ID_MEGARAID_SATA_150_6) ||
+		(adapter->pdev->subsystem_device !=
+		PCI_SUBSYS_ID_MEGARAID_SATA_150_4))) ||
+		(adapter->pdev->vendor == PCI_VENDOR_ID_LSI_LOGIC &&
+		adapter->pdev->device == PCI_DEVICE_ID_VERDE) ||
+		(adapter->pdev->vendor == PCI_VENDOR_ID_LSI_LOGIC &&
+		adapter->pdev->device == PCI_DEVICE_ID_DOBSON) ||
+		(adapter->pdev->vendor == PCI_VENDOR_ID_LSI_LOGIC &&
+		adapter->pdev->device == PCI_DEVICE_ID_LINDSAY) ||
+		(adapter->pdev->vendor == PCI_VENDOR_ID_DELL &&
+		adapter->pdev->device == PCI_DEVICE_ID_PERC4_DI_EVERGLADES) ||
+		(adapter->pdev->vendor == PCI_VENDOR_ID_DELL &&
+		adapter->pdev->device == PCI_DEVICE_ID_PERC4E_DI_KOBUK)) {
+		if (pci_set_dma_mask(adapter->pdev, DMA_64BIT_MASK)) {
+			con_log(CL_ANN, (KERN_WARNING
+				"megaraid: DMA mask for 64-bit failed\n"));
 
-		goto out_free_sysfs_res;
+			if (pci_set_dma_mask (adapter->pdev, DMA_32BIT_MASK)) {
+				con_log(CL_ANN, (KERN_WARNING
+					"megaraid: 32-bit DMA mask failed\n"));
+				goto out_free_sysfs_res;
+			}
+		}
 	}
 
 	// setup tasklet for DPC