PCI: skip ISA ioresource alignment on some systems

Skip ISA ioresource alignment on some systems

To conserve limited PCI i/o resource on some IBM multi-node systems, the
BIOS allocates (via _CRS) and expects the kernel to use addresses in
ranges currently excluded by pcibios_align_resource() [i386/pci/i386.c].
This change allows the kernel to use the currently excluded address
ranges on the IBM x3800, x3850, and x3950.

Signed-off-by: Gary Hade <gary.hade@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 42 insertions, 0 deletions

diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index bc8a44b..1dd6f3f 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -2,15 +2,57 @@
 #include <linux/acpi.h>
 #include <linux/init.h>
 #include <linux/irq.h>
+#include <linux/dmi.h>
 #include <asm/numa.h>
 #include "pci.h"
 
+static int __devinit can_skip_ioresource_align(struct dmi_system_id *d)
+{
+	pci_probe |= PCI_CAN_SKIP_ISA_ALIGN;
+	printk(KERN_INFO "PCI: %s detected, can skip ISA alignment\n", d->ident);
+	return 0;
+}
+
+static struct dmi_system_id acpi_pciprobe_dmi_table[] = {
+/*
+ * Systems where PCI IO resource ISA alignment can be skipped
+ * when the ISA enable bit in the bridge control is not set
+ */
+	{
+		.callback = can_skip_ioresource_align,
+		.ident = "IBM System x3800",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "x3800"),
+		},
+	},
+	{
+		.callback = can_skip_ioresource_align,
+		.ident = "IBM System x3850",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "x3850"),
+		},
+	},
+	{
+		.callback = can_skip_ioresource_align,
+		.ident = "IBM System x3950",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "x3950"),
+		},
+	},
+	{}
+};
+
 struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_device *device, int domain, int busnum)
 {
 	struct pci_bus *bus;
 	struct pci_sysdata *sd;
 	int pxm;
 
+	dmi_check_system(acpi_pciprobe_dmi_table);
+
 	/* Allocate per-root-bus (not per bus) arch-specific data.
 	 * TODO: leak; this memory is never freed.
 	 * It's arguable whether it's worth the trouble to care.