[SCSI] stex: add MSI support

This adds the MSI support (default 0=off)

Signed-off-by: Ed Lin <ed.lin@promise.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 43 insertions, 5 deletions

diff --git a/drivers/scsi/stex.c b/drivers/scsi/stex.c
index de6c30e37463..c4eb5c1cc1bc 100644
--- a/drivers/scsi/stex.c
+++ b/drivers/scsi/stex.c
@@ -292,11 +292,15 @@ struct st_hba {
         struct st_ccb *wait_ccb;
 
         unsigned int mu_status;
-        int out_req_cnt;
-
         unsigned int cardtype;
+        int msi_enabled;
+        int out_req_cnt;
 };
 
+static int msi;
+module_param(msi, int, 0);
+MODULE_PARM_DESC(msi, "Enable Message Signaled Interrupts(0=off, 1=on)");
+
 static const char console_inq_page[] =
 {
         0x03,0x00,0x03,0x03,0xFA,0x00,0x00,0x30,
@@ -1041,6 +1045,40 @@ static int stex_set_dma_mask(struct pci_dev * pdev)
         return ret;
 }
 
+static int stex_request_irq(struct st_hba *hba)
+{
+        struct pci_dev *pdev = hba->pdev;
+        int status;
+
+        if (msi) {
+                status = pci_enable_msi(pdev);
+                if (status != 0)
+                        printk(KERN_ERR DRV_NAME
+                                "(%s): error %d setting up MSI\n",
+                                pci_name(pdev), status);
+                else
+                        hba->msi_enabled = 1;
+        } else
+                hba->msi_enabled = 0;
+
+        status = request_irq(pdev->irq, stex_intr, IRQF_SHARED, DRV_NAME, hba);
+
+        if (status != 0) {
+                if (hba->msi_enabled)
+                        pci_disable_msi(pdev);
+        }
+        return status;
+}
+
+static void stex_free_irq(struct st_hba *hba)
+{
+        struct pci_dev *pdev = hba->pdev;
+
+        free_irq(pdev->irq, hba);
+        if (hba->msi_enabled)
+                pci_disable_msi(pdev);
+}
+
 static int __devinit
 stex_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
@@ -1125,7 +1163,7 @@ stex_probe(struct pci_dev *pdev, const struct pci_device_id *id)
         hba->host = host;
         hba->pdev = pdev;
 
-        err = request_irq(pdev->irq, stex_intr, IRQF_SHARED, DRV_NAME, hba);
+        err = stex_request_irq(hba);
         if (err) {
                 printk(KERN_ERR DRV_NAME "(%s): request irq failed\n",
                         pci_name(pdev));
@@ -1157,7 +1195,7 @@ stex_probe(struct pci_dev *pdev, const struct pci_device_id *id)
         return 0;
 
 out_free_irq:
-        free_irq(pdev->irq, hba);
+        stex_free_irq(hba);
 out_pci_free:
         dma_free_coherent(&pdev->dev, hba->dma_size,
                           hba->dma_mem, hba->dma_handle);
@@ -1216,7 +1254,7 @@ static void stex_hba_stop(struct st_hba *hba)
 
 static void stex_hba_free(struct st_hba *hba)
 {
-        free_irq(hba->pdev->irq, hba);
+        stex_free_irq(hba);
 
         iounmap(hba->mmio_base);