linux-kernel - [PATCH 2/8] PCI PCIe portdrv: Aviod using service devices with wrong interrupts

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Message-Id: <200901042350.00158.rjw@sisk.pl>
Date:	Sun, 4 Jan 2009 23:49:59 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Jesse Barnes <jbarnes@...tuousgeek.org>
Cc:	Linux PCI <linux-pci@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/8] PCI PCIe portdrv: Aviod using service devices with wrong interrupts

From: Rafael J. Wysocki <rjw@...k.pl>

The PCI Express port driver should not attempt to register service
devices that require the ability to generate interrupts if generating
interrupts is not possible.  Namely, if the port has no interrupt pin
configured and we cannot set up MSI or MSI-X for it, there is no way
it can generate interrupts and in such a case the port services that
rely on interrupts (PME, PCIe HP, AER) should not be enabled for it.

Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
---
 drivers/pci/pcie/portdrv_core.c |   40 +++++++++++++++++++++++++++-------------
 include/linux/pcieport_if.h     |    1 +
 2 files changed, 28 insertions(+), 13 deletions(-)

Index: linux-2.6/include/linux/pcieport_if.h
===================================================================
--- linux-2.6.orig/include/linux/pcieport_if.h
+++ linux-2.6/include/linux/pcieport_if.h
@@ -22,6 +22,7 @@
 #define PCIE_PORT_SERVICE_VC		8	/* Virtual Channel */
 
 /* Root/Upstream/Downstream Port's Interrupt Mode */
+#define PCIE_PORT_NO_IRQ		(-1)
 #define PCIE_PORT_INTx_MODE		0
 #define PCIE_PORT_MSI_MODE		1
 #define PCIE_PORT_MSIX_MODE		2
Index: linux-2.6/drivers/pci/pcie/portdrv_core.c
===================================================================
--- linux-2.6.orig/drivers/pci/pcie/portdrv_core.c
+++ linux-2.6/drivers/pci/pcie/portdrv_core.c
@@ -41,13 +41,15 @@ static void release_pcie_device(struct d
 static int assign_interrupt_mode(struct pci_dev *dev, int *vectors, int mask)
 {
 	int i, pos, nvec, status = -EINVAL;
-	int interrupt_mode = PCIE_PORT_INTx_MODE;
+	int interrupt_mode = PCIE_PORT_NO_IRQ;
 
 	/* Set INTx as default */
 	for (i = 0, nvec = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
 		if (mask & (1 << i)) 
 			nvec++;
 		vectors[i] = dev->irq;
+		if (dev->pin)
+			interrupt_mode = PCIE_PORT_INTx_MODE;
 	}
 
 	/* Select MSI-X over MSI if supported */		
@@ -137,7 +139,7 @@ static void pcie_device_init(struct pci_
 	dev->id.vendor = parent->vendor;
 	dev->id.device = parent->device;
 	dev->id.port_type = port_type;
-	dev->id.service_type = (1 << service_type);
+	dev->id.service_type = service_type;
 
 	/* Initialize generic device interface */
 	device = &dev->device;
@@ -227,23 +229,35 @@ int pcie_port_device_register(struct pci
 	/* Allocate child services if any */
 	for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
 		struct pcie_device *child;
+		int service = 1 << i;
+
+		if (!(capabilities & service))
+			continue;
 
-		if (capabilities & (1 << i)) {
-			child = alloc_pcie_device(
+		/*
+		 * Don't use service devices that require interrupts if there is
+		 * no way to generate them.
+		 */
+		if (irq_mode == PCIE_PORT_NO_IRQ
+		    && service != PCIE_PORT_SERVICE_VC)
+			continue;
+
+		child = alloc_pcie_device(
 				dev, 		/* parent */
 				type,		/* port type */
-				i,		/* service type */
+				service,	/* service type */
 				vectors[i],	/* irq */
 				irq_mode	/* interrupt mode */);
-			if (child) {
-				status = device_register(&child->device);
-				if (status) {
-					kfree(child);
-					continue;
-				}
-				get_device(&child->device);
-			}
+		if (!child)
+			continue;
+
+		status = device_register(&child->device);
+		if (status) {
+			kfree(child);
+			continue;
 		}
+
+		get_device(&child->device);
 	}
 	return 0;
 }

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