[SCSI] megaraid_sas: Fix probe_one to clear MSI-X flags in kdump

The following patch for megaraid_sas fixes megasas_probe_one() to
clear MSI-X flags in kdump when the 'reset_devices' kernel parameter
is passed in.

Signed-off-by: Adam Radford <aradford@gmail.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

2 files changed, 21 insertions, 1 deletions

diff --git a/drivers/scsi/megaraid/megaraid_sas.h b/drivers/scsi/megaraid/megaraid_sas.h
index 1b5e375732c0..e00ee4afdbc7 100644
--- a/drivers/scsi/megaraid/megaraid_sas.h
+++ b/drivers/scsi/megaraid/megaraid_sas.h
@@ -1477,4 +1477,7 @@ struct megasas_mgmt_info {
         int max_index;
 };
 
+#define msi_control_reg(base) (base + PCI_MSI_FLAGS)
+#define PCI_MSIX_FLAGS_ENABLE (1 << 15)
+
 #endif                          /*LSI_MEGARAID_SAS_H */
diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 050ec1694e68..a521e1afd738 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -3901,9 +3901,26 @@ fail_set_dma_mask:
 static int __devinit
 megasas_probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
 {
-        int rval;
+        int rval, pos;
         struct Scsi_Host *host;
         struct megasas_instance *instance;
+        u16 control = 0;
+
+        /* Reset MSI-X in the kdump kernel */
+        if (reset_devices) {
+                pos = pci_find_capability(pdev, PCI_CAP_ID_MSIX);
+                if (pos) {
+                        pci_read_config_word(pdev, msi_control_reg(pos),
+                                             &control);
+                        if (control & PCI_MSIX_FLAGS_ENABLE) {
+                                dev_info(&pdev->dev, "resetting MSI-X\n");
+                                pci_write_config_word(pdev,
+                                                      msi_control_reg(pos),
+                                                      control &
+                                                      ~PCI_MSIX_FLAGS_ENABLE);
+                        }
+                }
+        }
 
         /*
          * Announce PCI information