On Thu, Apr 26, 2012 at 9:35 PM, Wei Yang <weiyang.kernel@xxxxxxxxx> wrote:
> Bjorn
>
> One question, both Upstream and DownStream port is represented by
> pci_dev in kernel?
Yes.
> 2012/4/26 Bjorn Helgaas <bhelgaas@xxxxxxxxxx>:
>> 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-[0000:03]--+-00.0
>> \-01.0-[0000:xx]--+-[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@xxxxxxxxxx>
>> CC: Don Dutile <ddutile@xxxxxxxxxx>
>> CC: James Paradis <jim.paradis@xxxxxxxxxxx>
>> CC: Matthew Wilcox <matthew.wilcox@xxxxxxxxxxxxxxx>
>> CC: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
>> CC: Prarit Bhargava <prarit@xxxxxxxxxx>
>> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>> ---
>> Documentation/kernel-parameters.txt | 3 +++
>> arch/x86/pci/common.c | 16 ++++++++++++++++
>> drivers/pci/pci.c | 3 +++
>> drivers/pci/probe.c | 8 ++++++--
>> include/asm-generic/pci-bridge.h | 6 ++++++
>> 5 files changed, 34 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
>> index c1601e5..57c3870 100644
>> --- a/Documentation/kernel-parameters.txt
>> +++ b/Documentation/kernel-parameters.txt
>> @@ -2161,6 +2161,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>> 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 @@ static int __devinit assign_all_busses(const struct dmi_system_id *d)
>> }
>> #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 @@ static const struct dmi_system_id __devinitconst pciprobe_dmi_table[] = {
>> 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 9e31c0a..8f16900 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"
>>
>> @@ -3900,6 +3901,8 @@ static int __init pci_setup(char *str)
>> 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 5e1ca3c..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 unsigned no_next_fn(struct pci_dev *dev, unsigned fn)
>> 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 @@ enum {
>> 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
>>
>> --
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>
>
>
> --
> Richard Yang
> Help You, Help Me
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