[PATCH] sky2: support msi interrupt (revised)

This hardware supports Message Signaled interrupts.
When setting up, use software interrupt to check for bad hardware.

Signed-off-by: Stephen Hemminger <shemminger @osdl.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

2 files changed, 78 insertions, 0 deletions

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index 62733a6ec758..8ed4bd17c0cf 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -101,6 +101,10 @@ static int copybreak __read_mostly = 256;
 module_param(copybreak, int, 0);
 MODULE_PARM_DESC(copybreak, "Receive copy threshold");
 
+static int disable_msi = 0;
+module_param(disable_msi, int, 0);
+MODULE_PARM_DESC(disable_msi, "Disable Message Signaled Interrupt (MSI)");
+
 static const struct pci_device_id sky2_id_table[] = {
         { PCI_DEVICE(PCI_VENDOR_ID_SYSKONNECT, 0x9000) },
         { PCI_DEVICE(PCI_VENDOR_ID_SYSKONNECT, 0x9E00) },
@@ -3064,6 +3068,61 @@ static void __devinit sky2_show_addr(struct net_device *dev)
                        dev->dev_addr[3], dev->dev_addr[4], dev->dev_addr[5]);
 }
 
+/* Handle software interrupt used during MSI test */
+static irqreturn_t __devinit sky2_test_intr(int irq, void *dev_id,
+                                            struct pt_regs *regs)
+{
+        struct sky2_hw *hw = dev_id;
+        u32 status = sky2_read32(hw, B0_Y2_SP_ISRC2);
+
+        if (status == 0)
+                return IRQ_NONE;
+
+        if (status & Y2_IS_IRQ_SW) {
+                sky2_write8(hw, B0_CTST, CS_CL_SW_IRQ);
+                hw->msi = 1;
+        }
+        sky2_write32(hw, B0_Y2_SP_ICR, 2);
+
+        sky2_read32(hw, B0_IMSK);
+        return IRQ_HANDLED;
+}
+
+/* Test interrupt path by forcing a a software IRQ */
+static int __devinit sky2_test_msi(struct sky2_hw *hw)
+{
+        struct pci_dev *pdev = hw->pdev;
+        int i, err;
+
+        sky2_write32(hw, B0_IMSK, Y2_IS_IRQ_SW);
+
+        err = request_irq(pdev->irq, sky2_test_intr, SA_SHIRQ, DRV_NAME, hw);
+        if (err) {
+                printk(KERN_ERR PFX "%s: cannot assign irq %d\n",
+                       pci_name(pdev), pdev->irq);
+                return err;
+        }
+
+        sky2_write8(hw, B0_CTST, CS_ST_SW_IRQ);
+        wmb();
+
+        for (i = 0; i < 10; i++) {
+                barrier();
+                if (hw->msi)
+                        goto found;
+                mdelay(1);
+        }
+
+        err = -EOPNOTSUPP;
+        sky2_write8(hw, B0_CTST, CS_CL_SW_IRQ);
+ found:
+        sky2_write32(hw, B0_IMSK, 0);
+
+        free_irq(pdev->irq, hw);
+
+        return err;
+}
+
 static int __devinit sky2_probe(struct pci_dev *pdev,
                                 const struct pci_device_id *ent)
 {
@@ -3184,6 +3243,20 @@ static int __devinit sky2_probe(struct pci_dev *pdev,
                 }
         }
 
+        if (!disable_msi && pci_enable_msi(pdev) == 0) {
+                err = sky2_test_msi(hw);
+                if (err == -EOPNOTSUPP) {
+                        /* MSI test failed, go back to INTx mode */
+                        printk(KERN_WARNING PFX "%s: No interrupt was generated using MSI, "
+                               "switching to INTx mode. Please report this failure to "
+                               "the PCI maintainer and include system chipset information.\n",
+                               pci_name(pdev));
+                        pci_disable_msi(pdev);
+                }
+                else if (err)
+                        goto err_out_unregister;
+        }
+
         err = request_irq(pdev->irq, sky2_intr, SA_SHIRQ | SA_SAMPLE_RANDOM,
                           DRV_NAME, hw);
         if (err) {
@@ -3200,6 +3273,8 @@ static int __devinit sky2_probe(struct pci_dev *pdev,
         return 0;
 
 err_out_unregister:
+        if (hw->msi)
+                pci_disable_msi(pdev);
         if (dev1) {
                 unregister_netdev(dev1);
                 free_netdev(dev1);
@@ -3242,6 +3317,8 @@ static void __devexit sky2_remove(struct pci_dev *pdev)
         sky2_read8(hw, B0_CTST);
 
         free_irq(pdev->irq, hw);
+        if (hw->msi)
+                pci_disable_msi(pdev);
         pci_free_consistent(pdev, STATUS_LE_BYTES, hw->st_le, hw->st_dma);
         pci_release_regions(pdev);
         pci_disable_device(pdev);
diff --git a/drivers/net/sky2.h b/drivers/net/sky2.h
index 70525ac501de..fd12c289a238 100644
--- a/drivers/net/sky2.h
+++ b/drivers/net/sky2.h
@@ -1841,6 +1841,7 @@ struct sky2_hw {
         struct net_device    *dev[2];
 
         int                  pm_cap;
+        int                  msi;
         u8                   chip_id;
         u8                   chip_rev;
         u8                   copper;