[PATCH] chelsio: add MSI support

Using MSI can avoid sharing IRQ and associated overhead.
Tested on PCI-X.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 17 insertions, 3 deletions

diff --git a/drivers/net/chelsio/cxgb2.c b/drivers/net/chelsio/cxgb2.c
index 571aa06ddfd4..0ca5b07c1a6b 100644
--- a/drivers/net/chelsio/cxgb2.c
+++ b/drivers/net/chelsio/cxgb2.c
@@ -107,6 +107,10 @@ static int t1powersave = 1;	/* HW default is powersave mode. */
 module_param(t1powersave, int, 0);
 MODULE_PARM_DESC(t1powersave, "Enable/Disable T1 powersaving mode");
 
+static int disable_msi = 0;
+module_param(disable_msi, int, 0);
+MODULE_PARM_DESC(disable_msi, "Disable Message Signaled Interrupt (MSI)");
+
 static const char pci_speed[][4] = {
         "33", "66", "100", "133"
 };
@@ -215,11 +219,19 @@ static int cxgb_up(struct adapter *adapter)
         }
 
         t1_interrupts_clear(adapter);
-        if ((err = request_irq(adapter->pdev->irq,
-                               t1_select_intr_handler(adapter), IRQF_SHARED,
-                               adapter->name, adapter))) {
+
+        adapter->params.has_msi = !disable_msi && pci_enable_msi(adapter->pdev) == 0;
+        err = request_irq(adapter->pdev->irq,
+                          t1_select_intr_handler(adapter),
+                          adapter->params.has_msi ? 0 : IRQF_SHARED,
+                          adapter->name, adapter);
+        if (err) {
+                if (adapter->params.has_msi)
+                        pci_disable_msi(adapter->pdev);
+
                 goto out_err;
         }
+
         t1_sge_start(adapter->sge);
         t1_interrupts_enable(adapter);
  out_err:
@@ -234,6 +246,8 @@ static void cxgb_down(struct adapter *adapter)
         t1_sge_stop(adapter->sge);
         t1_interrupts_disable(adapter);
         free_irq(adapter->pdev->irq, adapter);
+        if (adapter->params.has_msi)
+                pci_disable_msi(adapter->pdev);
 }
 
 static int cxgb_open(struct net_device *dev)