[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