commit 28760489a3f1e136c5ae8581c0fa8f63511f2f4c
author Eric W. Biederman <ebiederm@aristanetworks.com> Wed Sep 09 14:09:24 2009 -0700
committer Jesse Barnes <jbarnes@virtuousgeek.org> Wed Sep 09 14:10:24 2009 -0700
tree a3c890e9c8d9e98385691d56f5c007d280514fe5
parent 0ba379ec0fb182a87b8891c5754abbcd9c035b4f

PCI: pcie: Ensure hotplug ports have a minimum number of resources

In general a BIOS may goof or we may hotplug in a hotplug controller.
In either case the kernel needs to reserve resources for plugging
in more devices in the future instead of creating a minimal resource
assignment.

We already do this for cardbus bridges I am just adding a variant
for pcie bridges.

v2: Make testing for pcie hotplug bridges based on a flag.

    So far we only set the flag for pcie but a header_quirk
    could easily be added for the non-standard pci hotplug
    bridges.

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/probe.c

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ab52840f..882383b 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -697,6 +697,23 @@
 	pdev->pcie_type = (reg16 & PCI_EXP_FLAGS_TYPE) >> 4;
 }
 
+static void set_pcie_hotplug_bridge(struct pci_dev *pdev)
+{
+	int pos;
+	u16 reg16;
+	u32 reg32;
+
+	pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
+	if (!pos)
+		return;
+	pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, &reg16);
+	if (!(reg16 & PCI_EXP_FLAGS_SLOT))
+		return;
+	pci_read_config_dword(pdev, pos + PCI_EXP_SLTCAP, &reg32);
+	if (reg32 & PCI_EXP_SLTCAP_HPC)
+		pdev->is_hotplug_bridge = 1;
+}
+
 #define LEGACY_IO_RESOURCE	(IORESOURCE_IO | IORESOURCE_PCI_FIXED)
 
 /**
@@ -804,6 +821,7 @@
 		pci_read_irq(dev);
 		dev->transparent = ((dev->class & 0xff) == 1);
 		pci_read_bases(dev, 2, PCI_ROM_ADDRESS1);
+		set_pcie_hotplug_bridge(dev);
 		break;
 
 	case PCI_HEADER_TYPE_CARDBUS:		    /* CardBus bridge header */