[PATCH v2 1/1] xHCI: supporting MSI/MSI-X

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>From f00f3c5df2393291a20f8b515d79d2d5638a85d1 Mon Sep 17 00:00:00 2001
From: Dong Nguyen <Dong.Nguyen@xxxxxxx>
Date: Mon, 10 May 2010 18:35:39 +0800
Subject: [PATCH] xHCI: supporting MSI/MSI-X

Enable MSI/MSI-X supporting in xhci driver.

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

Signed-off-by: Dong Nguyen <Dong.Nguyen@xxxxxxx>
Signed-off-by: Andiry Xu <andiry.xu@xxxxxxx>
---
 drivers/usb/host/xhci-pci.c |    1 -
 drivers/usb/host/xhci.c     |  152 ++++++++++++++++++++++++++++++++----------
 drivers/usb/host/xhci.h     |    2 +-
 3 files changed, 117 insertions(+), 38 deletions(-)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 9714db9..f319112 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -113,7 +113,6 @@ static const struct hc_driver xhci_pci_hc_driver = {
 	/*
 	 * generic hardware linkage
 	 */
-	.irq =			xhci_irq,
 	.flags =		HCD_MEMORY | HCD_USB3,
 
 	/*
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index a22a1e6..43d7fc4 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>
@@ -33,6 +34,7 @@
 
 /* Some 0.95 hardware can't handle the chain bit on a Link TRB being cleared */
 static int link_quirk;
+static irqreturn_t xhci_msi_irq(int irq, struct usb_hcd *hcd);
 module_param(link_quirk, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(link_quirk, "Don't clear the chain bit on a link TRB");
 
@@ -133,22 +135,78 @@ int xhci_reset(struct xhci_hcd *xhci)
 	return handshake(xhci, &xhci->op_regs->command, CMD_RESET, 0, 250 * 1000);
 }
 
+/*
+ * 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);
+
+	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 {
+		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;
+}
 
-#if 0
-/* Set up MSI-X table for entry 0 (may claim other entries later) */
+/*
+ * Set up MSI-X
+ */
 static int xhci_setup_msix(struct xhci_hcd *xhci)
 {
-	int ret;
+	int	i, ret = 0;
+	int	cpus = num_online_cpus();
+	int	msix_vecs, max_vecs;
 	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);
+	xhci->msix_entries = NULL;
+	max_vecs = HCS_MAX_INTRS(xhci->hcs_params1);
+	msix_vecs = min(cpus + 1, max_vecs);
+	xhci->msix_count = msix_vecs;
+
+	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) {
@@ -156,20 +214,18 @@ 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);
@@ -177,21 +233,23 @@ 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).
@@ -314,6 +372,16 @@ hw_died:
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t xhci_msi_irq(int irq, struct usb_hcd *hcd)
+{
+	irqreturn_t ret;
+
+	clear_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
+
+	ret = xhci_irq(hcd);
+	return ret;
+}
+
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 void xhci_event_ring_work(unsigned long arg)
 {
@@ -385,21 +453,35 @@ 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(hcd->self.controller);
 	void (*doorbell)(struct xhci_hcd *) = NULL;
 
 	hcd->uses_new_polling = 1;
 	hcd->poll_rh = 0;
 
 	xhci_dbg(xhci, "xhci_run\n");
-#if 0	/* FIXME: MSI not setup yet */
+
 	/* Do this at the very last minute */
 	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 IRQ */
+		ret = request_irq(pdev->irq,
+					(irq_handler_t)xhci_irq,
+					IRQF_SHARED,
+					"xhci_hcd",
+					xhci_to_hcd(xhci));
+		if (ret) {
+			xhci_err(xhci,
+				"Failed to request irq interrupt\n");
+				return ret;
+		}
+	}
 
-	return -ENOSYS;
-#endif
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 	init_timer(&xhci->event_ring_timer);
 	xhci->event_ring_timer.data = (unsigned long) xhci;
@@ -483,9 +565,8 @@ void xhci_stop(struct usb_hcd *hcd)
 	xhci_reset(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;
@@ -521,9 +602,7 @@ void xhci_shutdown(struct usb_hcd *hcd)
 	xhci_halt(xhci);
 	spin_unlock_irq(&xhci->lock);
 
-#if 0
 	xhci_cleanup_msix(xhci);
-#endif
 
 	xhci_dbg(xhci, "xhci_shutdown completed - status = %x\n",
 		    xhci_readl(xhci, &xhci->op_regs->status));
@@ -803,6 +882,7 @@ int xhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 
 	xhci = hcd_to_xhci(hcd);
 	spin_lock_irqsave(&xhci->lock, flags);
+
 	/* Make sure the URB hasn't completed or been unlinked already */
 	ret = usb_hcd_check_unlink_urb(hcd, urb, status);
 	if (ret || !urb->hcpriv)
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index fb3440b..a32f644 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1121,7 +1121,7 @@ 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 */
-- 
1.6.3.3




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