PCI: work around Stratus ftServer broken PCIe hierarchy
A PCIe downstream port is a P2P bridge. Its secondary interface is
a link that should lead only to device 0 (unless ARI is enabled)[1], so
we don't probe for non-zero device numbers.
Some Stratus ftServer systems have a PCIe downstream port (02:00.0) that
leads to both an upstream port (03:00.0) and a downstream port (03:01.0),
and 03:01.0 has important devices below it:
[0000:02]-+-00.0-[03-3c]--+-00.0-[04-09]--...
\-01.0-[0a-0d]--+-[USB]
+-[NIC]
+-...
Previously, we didn't enumerate device 03:01.0, so USB and the network
didn't work. This patch adds a DMI quirk to scan all device numbers,
not just 0, below a downstream port.
Based on a patch by Prarit Bhargava.
[1] PCIe spec r3.0, sec 7.3.1
CC: Myron Stowe <mstowe@redhat.com>
CC: Don Dutile <ddutile@redhat.com>
CC: James Paradis <james.paradis@stratus.com>
CC: Matthew Wilcox <matthew.r.wilcox@intel.com>
CC: Jesse Barnes <jbarnes@virtuousgeek.org>
CC: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c1601e5..f995195 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2161,6 +2161,9 @@
on: Turn realloc on
realloc same as realloc=on
noari do not use PCIe ARI.
+ pcie_scan_all Scan all possible PCIe devices. Otherwise we
+ only look for one device below a PCIe downstream
+ port.
pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
Management.
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index 323481e..16c5d78 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -11,6 +11,7 @@
#include <linux/dmi.h>
#include <linux/slab.h>
+#include <asm-generic/pci-bridge.h>
#include <asm/acpi.h>
#include <asm/segment.h>
#include <asm/io.h>
@@ -229,6 +230,14 @@
}
#endif
+static int __devinit set_scan_all(const struct dmi_system_id *d)
+{
+ printk(KERN_INFO "PCI: %s detected, enabling pci=pcie_scan_all\n",
+ d->ident);
+ pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS);
+ return 0;
+}
+
static const struct dmi_system_id __devinitconst pciprobe_dmi_table[] = {
#ifdef __i386__
/*
@@ -420,6 +429,13 @@
DMI_MATCH(DMI_PRODUCT_NAME, "ProLiant DL585 G2"),
},
},
+ {
+ .callback = set_scan_all,
+ .ident = "Stratus/NEC ftServer",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "ftServer"),
+ },
+ },
{}
};
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 111569c..8e6c388 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -22,6 +22,7 @@
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/pm_runtime.h>
+#include <asm-generic/pci-bridge.h>
#include <asm/setup.h>
#include "pci.h"
@@ -3893,6 +3894,8 @@
pcie_bus_config = PCIE_BUS_PERFORMANCE;
} else if (!strncmp(str, "pcie_bus_peer2peer", 18)) {
pcie_bus_config = PCIE_BUS_PEER2PEER;
+ } else if (!strncmp(str, "pcie_scan_all", 13)) {
+ pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS);
} else {
printk(KERN_ERR "PCI: Unknown option `%s'\n",
str);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 5e1ca3c5..2dc8675 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -10,6 +10,7 @@
#include <linux/module.h>
#include <linux/cpumask.h>
#include <linux/pci-aspm.h>
+#include <asm-generic/pci-bridge.h>
#include "pci.h"
#define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */
@@ -1395,10 +1396,13 @@
static int only_one_child(struct pci_bus *bus)
{
struct pci_dev *parent = bus->self;
+
if (!parent || !pci_is_pcie(parent))
return 0;
- if (parent->pcie_type == PCI_EXP_TYPE_ROOT_PORT ||
- parent->pcie_type == PCI_EXP_TYPE_DOWNSTREAM)
+ if (parent->pcie_type == PCI_EXP_TYPE_ROOT_PORT)
+ return 1;
+ if (parent->pcie_type == PCI_EXP_TYPE_DOWNSTREAM &&
+ !pci_has_flag(PCI_SCAN_ALL_PCIE_DEVS))
return 1;
return 0;
}
diff --git a/include/asm-generic/pci-bridge.h b/include/asm-generic/pci-bridge.h
index a5b5d5a..20db2e5 100644
--- a/include/asm-generic/pci-bridge.h
+++ b/include/asm-generic/pci-bridge.h
@@ -30,6 +30,12 @@
PCI_ENABLE_PROC_DOMAINS = 0x00000010,
/* ... except for domain 0 */
PCI_COMPAT_DOMAIN_0 = 0x00000020,
+
+ /* PCIe downstream ports are bridges that normally lead to only a
+ * device 0, but if this is set, we scan all possible devices, not
+ * just device 0.
+ */
+ PCI_SCAN_ALL_PCIE_DEVS = 0x00000040,
};
#ifdef CONFIG_PCI