USB: xHCI: Supporting MSI/MSI-X

Enable MSI/MSI-X supporting in xhci driver.

Provide the mechanism to fall back using MSI and Legacy IRQs
if MSI-X IRQs register failed.

Signed-off-by: Dong Nguyen <Dong.Nguyen@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>,
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 128 insertions, 41 deletions

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index c5753c797735..5cca00a6d09d 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2085,6 +2085,7 @@ irqreturn_t usb_hcd_irq (int irq, void *__hcd)
         local_irq_restore(flags);
         return rc;
 }
+EXPORT_SYMBOL_GPL(usb_hcd_irq);
 
 /*-------------------------------------------------------------------------*/
 
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 5e73386b3899..3106d22ae053 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -20,6 +20,7 @@
  * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#include <linux/pci.h>
 #include <linux/irq.h>
 #include <linux/log2.h>
 #include <linux/module.h>
@@ -171,22 +172,95 @@ int xhci_reset(struct xhci_hcd *xhci)
         return handshake(xhci, &xhci->op_regs->status, STS_CNR, 0, 250 * 1000);
 }
 
+static irqreturn_t xhci_msi_irq(int irq, struct usb_hcd *hcd)
+{
+        irqreturn_t ret;
 
-#if 0
-/* Set up MSI-X table for entry 0 (may claim other entries later) */
-static int xhci_setup_msix(struct xhci_hcd *xhci)
+        set_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
+
+        ret = xhci_irq(hcd);
+
+        return ret;
+}
+
+/*
+ * Free IRQs
+ * free all IRQs request
+ */
+static void xhci_free_irq(struct xhci_hcd *xhci)
+{
+        int i;
+        struct pci_dev *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
+
+        /* return if using legacy interrupt */
+        if (xhci_to_hcd(xhci)->irq >= 0)
+                return;
+
+        if (xhci->msix_entries) {
+                for (i = 0; i < xhci->msix_count; i++)
+                        if (xhci->msix_entries[i].vector)
+                                free_irq(xhci->msix_entries[i].vector,
+                                                xhci_to_hcd(xhci));
+        } else if (pdev->irq >= 0)
+                free_irq(pdev->irq, xhci_to_hcd(xhci));
+
+        return;
+}
+
+/*
+ * Set up MSI
+ */
+static int xhci_setup_msi(struct xhci_hcd *xhci)
 {
         int ret;
+        struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
+
+        ret = pci_enable_msi(pdev);
+        if (ret) {
+                xhci_err(xhci, "failed to allocate MSI entry\n");
+                return ret;
+        }
+
+        ret = request_irq(pdev->irq, (irq_handler_t)xhci_msi_irq,
+                                0, "xhci_hcd", xhci_to_hcd(xhci));
+        if (ret) {
+                xhci_err(xhci, "disable MSI interrupt\n");
+                pci_disable_msi(pdev);
+        }
+
+        return ret;
+}
+
+/*
+ * Set up MSI-X
+ */
+static int xhci_setup_msix(struct xhci_hcd *xhci)
+{
+        int i, ret = 0;
         struct pci_dev *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
 
-        xhci->msix_count = 0;
-        /* XXX: did I do this right?  ixgbe does kcalloc for more than one */
-        xhci->msix_entries = kmalloc(sizeof(struct msix_entry), GFP_KERNEL);
+        /*
+         * calculate number of msi-x vectors supported.
+         * - HCS_MAX_INTRS: the max number of interrupts the host can handle,
+         *   with max number of interrupters based on the xhci HCSPARAMS1.
+         * - num_online_cpus: maximum msi-x vectors per CPUs core.
+         *   Add additional 1 vector to ensure always available interrupt.
+         */
+        xhci->msix_count = min(num_online_cpus() + 1,
+                                HCS_MAX_INTRS(xhci->hcs_params1));
+
+        xhci->msix_entries =
+                kmalloc((sizeof(struct msix_entry))*xhci->msix_count,
+                                GFP_KERNEL);
         if (!xhci->msix_entries) {
                 xhci_err(xhci, "Failed to allocate MSI-X entries\n");
                 return -ENOMEM;
         }
-        xhci->msix_entries[0].entry = 0;
+
+        for (i = 0; i < xhci->msix_count; i++) {
+                xhci->msix_entries[i].entry = i;
+                xhci->msix_entries[i].vector = 0;
+        }
 
         ret = pci_enable_msix(pdev, xhci->msix_entries, xhci->msix_count);
         if (ret) {
@@ -194,20 +268,19 @@ static int xhci_setup_msix(struct xhci_hcd *xhci)
                 goto free_entries;
         }
 
-        /*
-         * Pass the xhci pointer value as the request_irq "cookie".
-         * If more irqs are added, this will need to be unique for each one.
-         */
-        ret = request_irq(xhci->msix_entries[0].vector, &xhci_irq, 0,
-                        "xHCI", xhci_to_hcd(xhci));
-        if (ret) {
-                xhci_err(xhci, "Failed to allocate MSI-X interrupt\n");
-                goto disable_msix;
+        for (i = 0; i < xhci->msix_count; i++) {
+                ret = request_irq(xhci->msix_entries[i].vector,
+                                (irq_handler_t)xhci_msi_irq,
+                                0, "xhci_hcd", xhci_to_hcd(xhci));
+                if (ret)
+                        goto disable_msix;
         }
-        xhci_dbg(xhci, "Finished setting up MSI-X\n");
-        return 0;
+
+        return ret;
 
 disable_msix:
+        xhci_err(xhci, "disable MSI-X interrupt\n");
+        xhci_free_irq(xhci);
         pci_disable_msix(pdev);
 free_entries:
         kfree(xhci->msix_entries);
@@ -215,21 +288,23 @@ free_entries:
         return ret;
 }
 
-/* XXX: code duplication; can xhci_setup_msix call this? */
 /* Free any IRQs and disable MSI-X */
 static void xhci_cleanup_msix(struct xhci_hcd *xhci)
 {
         struct pci_dev *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-        if (!xhci->msix_entries)
-                return;
 
-        free_irq(xhci->msix_entries[0].vector, xhci);
-        pci_disable_msix(pdev);
-        kfree(xhci->msix_entries);
-        xhci->msix_entries = NULL;
-        xhci_dbg(xhci, "Finished cleaning up MSI-X\n");
+        xhci_free_irq(xhci);
+
+        if (xhci->msix_entries) {
+                pci_disable_msix(pdev);
+                kfree(xhci->msix_entries);
+                xhci->msix_entries = NULL;
+        } else {
+                pci_disable_msi(pdev);
+        }
+
+        return;
 }
-#endif
 
 /*
  * Initialize memory for HCD and xHC (one-time init).
@@ -423,20 +498,36 @@ int xhci_run(struct usb_hcd *hcd)
 {
         u32 temp;
         u64 temp_64;
+        u32 ret;
         struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+        struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
         void (*doorbell)(struct xhci_hcd *) = NULL;
 
         hcd->uses_new_polling = 1;
 
         xhci_dbg(xhci, "xhci_run\n");
-#if 0   /* FIXME: MSI not setup yet */
-        /* Do this at the very last minute */
+        /* unregister the legacy interrupt */
+        if (hcd->irq)
+                free_irq(hcd->irq, hcd);
+        hcd->irq = -1;
+
         ret = xhci_setup_msix(xhci);
-        if (!ret)
-                return ret;
+        if (ret)
+                /* fall back to msi*/
+                ret = xhci_setup_msi(xhci);
+
+        if (ret) {
+                /* fall back to legacy interrupt*/
+                ret = request_irq(pdev->irq, &usb_hcd_irq, IRQF_SHARED,
+                                        hcd->irq_descr, hcd);
+                if (ret) {
+                        xhci_err(xhci, "request interrupt %d failed\n",
+                                        pdev->irq);
+                        return ret;
+                }
+                hcd->irq = pdev->irq;
+        }
 
-        return -ENOSYS;
-#endif
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
         init_timer(&xhci->event_ring_timer);
         xhci->event_ring_timer.data = (unsigned long) xhci;
@@ -520,11 +611,9 @@ void xhci_stop(struct usb_hcd *hcd)
         spin_lock_irq(&xhci->lock);
         xhci_halt(xhci);
         xhci_reset(xhci);
+        xhci_cleanup_msix(xhci);
         spin_unlock_irq(&xhci->lock);
 
-#if 0   /* No MSI yet */
-        xhci_cleanup_msix(xhci);
-#endif
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
         /* Tell the event ring poll function not to reschedule */
         xhci->zombie = 1;
@@ -558,11 +647,8 @@ void xhci_shutdown(struct usb_hcd *hcd)
 
         spin_lock_irq(&xhci->lock);
         xhci_halt(xhci);
-        spin_unlock_irq(&xhci->lock);
-
-#if 0
         xhci_cleanup_msix(xhci);
-#endif
+        spin_unlock_irq(&xhci->lock);
 
         xhci_dbg(xhci, "xhci_shutdown completed - status = %x\n",
                     xhci_readl(xhci, &xhci->op_regs->status));
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 6c7e3430ec93..5bc03d1c2beb 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1130,7 +1130,7 @@ struct xhci_hcd {
         int             page_size;
         /* Valid values are 12 to 20, inclusive */
         int             page_shift;
-        /* only one MSI vector for now, but might need more later */
+        /* msi-x vectors */
         int             msix_count;
         struct msix_entry       *msix_entries;
         /* data structures */