Re: [PATCH v1] PCI: Make PCI_SCAN_ALL_PCIE_DEVS work for Root as well as Downstream Ports

[Christian Zigotzky]

Hi Bjorn,

Sorry for my late answer. The X1000 boots and works since yesterday. I think 
the following patch solved the issue: 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c591c2e36ccc9a08f265841d2fd68e35327ab3c4

Cheers,
Christian

Sent from my iPhone

> On 10. Feb 2018, at 16:43, Bjorn Helgaas  wrote:
> 
>> On Sat, Feb 10, 2018 at 09:05:40AM +0100, Christian Zigotzky wrote:
>> Hi All,
>> 
>> The AmigaOne X1000 doesn’t boot anymore since the PCI updates. I
>> have seen, that the PCI updates are different to the updates below.
>> The code below works but the latest not. Is there a problem with the
>> latest PCI updates currently?
> 
> I'm not aware of a problem, and it *looks* like the patch below is in
> Linus' tree (I'm looking at 9a61df9e5f74 ("Merge tag 'kbuild-v4.16-2'
> of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild")).
> 
> I assume you're still booting with "pci=pcie_scan_all", since I don't
> think we ever got a quirk to set PCI_SCAN_ALL_PCIE_DEVS automatically.
> 
> If AmigaOne X1000 doesn't boot with "pci=pcie_scan_all", can you diff
> the working only_one_child() with the current upstream?  I compared
> the version in my pci/enumeration branch with what's upstream, and
> they're identical.  So maybe the original patch I applied was wrong?
> 
> If you have a patch that works, can you post it and maybe I can sort
> out what's different?
> 
>> On 2. Dec 2017, at 20:18, Bjorn Helgaas  wrote:
>> 
>> On Fri, Dec 01, 2017 at 06:27:10PM -0600, Bjorn Helgaas wrote:
>> From: Bjorn Helgaas 
>> 
>> PCIe Downstream Ports normally have only a Device 0 below them.  To
>> optimize enumeration, we don't scan for other devices *unless* the
>> PCI_SCAN_ALL_PCIE_DEVS flag is set by set by quirks or the
>> "pci=pcie_scan_all" kernel parameter.
>> 
>> Previously PCI_SCAN_ALL_PCIE_DEVS only affected scanning below Switch
>> Downstream Ports, not Root Ports.
>> 
>> But the "Nemo" system, also known as the AmigaOne X1000, has a PA Semi Root
>> Port whose link leads to an AMD/ATI SB600 South Bridge.  The Root Port is a
>> PCIe device, of course, but the SB600 contains only conventional PCI
>> devices with no visible PCIe port.
>> 
>> Simplify and restructure only_one_child() so that we scan for all possible
>> devices below Root Ports as well as Switch Downstream Ports when
>> PCI_SCAN_ALL_PCIE_DEVS is set.
>> 
>> This is enough to make Nemo work with "pci=pcie_scan_all".  We would also
>> like to add a quirk to set PCI_SCAN_ALL_PCIE_DEVS automatically on Nemo so
>> users wouldn't have to use the "pci=pcie_scan_all" parameter, but we don't
>> have that yet.
>> 
>> Link: 
>> https://lkml.kernel.org/r/CAErSpo55Q8Q=5p6_+uu7ahnw+53ibvdnrxxrzrv9qnur_9e...@mail.gmail.com
>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=198057
>> Reported-and-Tested-by: Christian Zigotzky 
>> Signed-off-by: Bjorn Helgaas 
>> 
>> Applied to pci/enumeration for v4.16.
>> 
>> ---
>> drivers/pci/probe.c |   25 +++--
>> 1 file changed, 15 insertions(+), 10 deletions(-)
>> 
>> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
>> index 14e0ea1ff38b..303c0cb0550c 100644
>> --- a/drivers/pci/probe.c
>> +++ b/drivers/pci/probe.c
>> @@ -2215,22 +2215,27 @@ static unsigned next_fn(struct pci_bus *bus, struct 
>> pci_dev *dev, unsigned fn)
>> 
>> static int only_one_child(struct pci_bus *bus)
>> {
>> -struct pci_dev *parent = bus->self;
>> +struct pci_dev *bridge = bus->self;
>> 
>> -if (!parent || !pci_is_pcie(parent))
>> +/*
>> + * Systems with unusual topologies set PCI_SCAN_ALL_PCIE_DEVS so
>> + * we scan for all possible devices, not just Device 0.
>> + */
>> +if (pci_has_flag(PCI_SCAN_ALL_PCIE_DEVS))
>>   return 0;
>> -if (pci_pcie_type(parent) == PCI_EXP_TYPE_ROOT_PORT)
>> -return 1;
>> 
>>   /*
>> - * PCIe downstream ports are bridges that normally lead to only a
>> - * device 0, but if PCI_SCAN_ALL_PCIE_DEVS is set, scan all
>> - * possible devices, not just device 0.  See PCIe spec r3.0,
>> - * sec 7.3.1.
>> + * A PCIe Downstream Port normally leads to a Link with only Device
>> + * 0 on it (PCIe spec r3.1, sec 7.3.1).  As an optimization, scan
>> + * only for Device 0 in that situation.
>> + *
>> + * Checking has_secondary_link is a hack to identify Downstream
>> + * Ports because sometimes Switches are configured such that the
>> + * PCIe Port Type labels are backwards.
>>*/
>> -if (parent->has_secondary_link &&
>> -!pci_has_flag(PCI_SCAN_ALL_PCIE_DEVS))
>> +if (bridge && pci_is_pcie(bridge) && bridge->has_secondary_link)
>>   return 1;
>> +
>>   return 0;
>> }
>> 

Re: [PATCH v1] PCI: Make PCI_SCAN_ALL_PCIE_DEVS work for Root as well as Downstream Ports

[Bjorn Helgaas]

On Sat, Feb 10, 2018 at 09:05:40AM +0100, Christian Zigotzky wrote:
> Hi All,
> 
> The AmigaOne X1000 doesn’t boot anymore since the PCI updates. I
> have seen, that the PCI updates are different to the updates below.
> The code below works but the latest not. Is there a problem with the
> latest PCI updates currently?

I'm not aware of a problem, and it *looks* like the patch below is in
Linus' tree (I'm looking at 9a61df9e5f74 ("Merge tag 'kbuild-v4.16-2'
of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild")).

I assume you're still booting with "pci=pcie_scan_all", since I don't
think we ever got a quirk to set PCI_SCAN_ALL_PCIE_DEVS automatically.

If AmigaOne X1000 doesn't boot with "pci=pcie_scan_all", can you diff
the working only_one_child() with the current upstream?  I compared
the version in my pci/enumeration branch with what's upstream, and
they're identical.  So maybe the original patch I applied was wrong?

If you have a patch that works, can you post it and maybe I can sort
out what's different?

> On 2. Dec 2017, at 20:18, Bjorn Helgaas  wrote:
> 
> On Fri, Dec 01, 2017 at 06:27:10PM -0600, Bjorn Helgaas wrote:
> From: Bjorn Helgaas 
> 
> PCIe Downstream Ports normally have only a Device 0 below them.  To
> optimize enumeration, we don't scan for other devices *unless* the
> PCI_SCAN_ALL_PCIE_DEVS flag is set by set by quirks or the
> "pci=pcie_scan_all" kernel parameter.
> 
> Previously PCI_SCAN_ALL_PCIE_DEVS only affected scanning below Switch
> Downstream Ports, not Root Ports.
> 
> But the "Nemo" system, also known as the AmigaOne X1000, has a PA Semi Root
> Port whose link leads to an AMD/ATI SB600 South Bridge.  The Root Port is a
> PCIe device, of course, but the SB600 contains only conventional PCI
> devices with no visible PCIe port.
> 
> Simplify and restructure only_one_child() so that we scan for all possible
> devices below Root Ports as well as Switch Downstream Ports when
> PCI_SCAN_ALL_PCIE_DEVS is set.
> 
> This is enough to make Nemo work with "pci=pcie_scan_all".  We would also
> like to add a quirk to set PCI_SCAN_ALL_PCIE_DEVS automatically on Nemo so
> users wouldn't have to use the "pci=pcie_scan_all" parameter, but we don't
> have that yet.
> 
> Link: 
> https://lkml.kernel.org/r/CAErSpo55Q8Q=5p6_+uu7ahnw+53ibvdnrxxrzrv9qnur_9e...@mail.gmail.com
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=198057
> Reported-and-Tested-by: Christian Zigotzky 
> Signed-off-by: Bjorn Helgaas 
> 
> Applied to pci/enumeration for v4.16.
> 
> ---
> drivers/pci/probe.c |   25 +++--
> 1 file changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 14e0ea1ff38b..303c0cb0550c 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -2215,22 +2215,27 @@ static unsigned next_fn(struct pci_bus *bus, struct 
> pci_dev *dev, unsigned fn)
> 
> static int only_one_child(struct pci_bus *bus)
> {
> -struct pci_dev *parent = bus->self;
> +struct pci_dev *bridge = bus->self;
> 
> -if (!parent || !pci_is_pcie(parent))
> +/*
> + * Systems with unusual topologies set PCI_SCAN_ALL_PCIE_DEVS so
> + * we scan for all possible devices, not just Device 0.
> + */
> +if (pci_has_flag(PCI_SCAN_ALL_PCIE_DEVS))
>return 0;
> -if (pci_pcie_type(parent) == PCI_EXP_TYPE_ROOT_PORT)
> -return 1;
> 
>/*
> - * PCIe downstream ports are bridges that normally lead to only a
> - * device 0, but if PCI_SCAN_ALL_PCIE_DEVS is set, scan all
> - * possible devices, not just device 0.  See PCIe spec r3.0,
> - * sec 7.3.1.
> + * A PCIe Downstream Port normally leads to a Link with only Device
> + * 0 on it (PCIe spec r3.1, sec 7.3.1).  As an optimization, scan
> + * only for Device 0 in that situation.
> + *
> + * Checking has_secondary_link is a hack to identify Downstream
> + * Ports because sometimes Switches are configured such that the
> + * PCIe Port Type labels are backwards.
> */
> -if (parent->has_secondary_link &&
> -!pci_has_flag(PCI_SCAN_ALL_PCIE_DEVS))
> +if (bridge && pci_is_pcie(bridge) && bridge->has_secondary_link)
>return 1;
> +
>return 0;
> }
> 

Re: [PATCH v1] PCI: Make PCI_SCAN_ALL_PCIE_DEVS work for Root as well as Downstream Ports

[Christian Zigotzky]

Hi All,

The AmigaOne X1000 doesn’t boot anymore since the PCI updates. I have seen, 
that the PCI updates are different to the updates below. The code below works 
but the latest not. Is there a problem with the latest PCI updates currently?

Thanks,
Christian

Sent from my iPhone

On 2. Dec 2017, at 20:18, Bjorn Helgaas  wrote:

On Fri, Dec 01, 2017 at 06:27:10PM -0600, Bjorn Helgaas wrote:
From: Bjorn Helgaas 

PCIe Downstream Ports normally have only a Device 0 below them.  To
optimize enumeration, we don't scan for other devices *unless* the
PCI_SCAN_ALL_PCIE_DEVS flag is set by set by quirks or the
"pci=pcie_scan_all" kernel parameter.

Previously PCI_SCAN_ALL_PCIE_DEVS only affected scanning below Switch
Downstream Ports, not Root Ports.

But the "Nemo" system, also known as the AmigaOne X1000, has a PA Semi Root
Port whose link leads to an AMD/ATI SB600 South Bridge.  The Root Port is a
PCIe device, of course, but the SB600 contains only conventional PCI
devices with no visible PCIe port.

Simplify and restructure only_one_child() so that we scan for all possible
devices below Root Ports as well as Switch Downstream Ports when
PCI_SCAN_ALL_PCIE_DEVS is set.

This is enough to make Nemo work with "pci=pcie_scan_all".  We would also
like to add a quirk to set PCI_SCAN_ALL_PCIE_DEVS automatically on Nemo so
users wouldn't have to use the "pci=pcie_scan_all" parameter, but we don't
have that yet.

Link: 
https://lkml.kernel.org/r/CAErSpo55Q8Q=5p6_+uu7ahnw+53ibvdnrxxrzrv9qnur_9e...@mail.gmail.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=198057
Reported-and-Tested-by: Christian Zigotzky 
Signed-off-by: Bjorn Helgaas 

Applied to pci/enumeration for v4.16.

---
drivers/pci/probe.c |   25 +++--
1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 14e0ea1ff38b..303c0cb0550c 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2215,22 +2215,27 @@ static unsigned next_fn(struct pci_bus *bus, struct 
pci_dev *dev, unsigned fn)

static int only_one_child(struct pci_bus *bus)
{
-struct pci_dev *parent = bus->self;
+struct pci_dev *bridge = bus->self;

-if (!parent || !pci_is_pcie(parent))
+/*
+ * Systems with unusual topologies set PCI_SCAN_ALL_PCIE_DEVS so
+ * we scan for all possible devices, not just Device 0.
+ */
+if (pci_has_flag(PCI_SCAN_ALL_PCIE_DEVS))
   return 0;
-if (pci_pcie_type(parent) == PCI_EXP_TYPE_ROOT_PORT)
-return 1;

   /*
- * PCIe downstream ports are bridges that normally lead to only a
- * device 0, but if PCI_SCAN_ALL_PCIE_DEVS is set, scan all
- * possible devices, not just device 0.  See PCIe spec r3.0,
- * sec 7.3.1.
+ * A PCIe Downstream Port normally leads to a Link with only Device
+ * 0 on it (PCIe spec r3.1, sec 7.3.1).  As an optimization, scan
+ * only for Device 0 in that situation.
+ *
+ * Checking has_secondary_link is a hack to identify Downstream
+ * Ports because sometimes Switches are configured such that the
+ * PCIe Port Type labels are backwards.
*/
-if (parent->has_secondary_link &&
-!pci_has_flag(PCI_SCAN_ALL_PCIE_DEVS))
+if (bridge && pci_is_pcie(bridge) && bridge->has_secondary_link)
   return 1;
+
   return 0;
}

Re: [PATCH v1] PCI: Make PCI_SCAN_ALL_PCIE_DEVS work for Root as well as Downstream Ports

[Michael Ellerman]

Bjorn Helgaas  writes:

> On Fri, Dec 01, 2017 at 06:27:10PM -0600, Bjorn Helgaas wrote:
>> From: Bjorn Helgaas 
>> 
>> PCIe Downstream Ports normally have only a Device 0 below them.  To
>> optimize enumeration, we don't scan for other devices *unless* the
>> PCI_SCAN_ALL_PCIE_DEVS flag is set by set by quirks or the
>> "pci=pcie_scan_all" kernel parameter.
>> 
>> Previously PCI_SCAN_ALL_PCIE_DEVS only affected scanning below Switch
>> Downstream Ports, not Root Ports.
>> 
>> But the "Nemo" system, also known as the AmigaOne X1000, has a PA Semi Root
>> Port whose link leads to an AMD/ATI SB600 South Bridge.  The Root Port is a
>> PCIe device, of course, but the SB600 contains only conventional PCI
>> devices with no visible PCIe port.
>> 
>> Simplify and restructure only_one_child() so that we scan for all possible
>> devices below Root Ports as well as Switch Downstream Ports when
>> PCI_SCAN_ALL_PCIE_DEVS is set.
>> 
>> This is enough to make Nemo work with "pci=pcie_scan_all".  We would also
>> like to add a quirk to set PCI_SCAN_ALL_PCIE_DEVS automatically on Nemo so
>> users wouldn't have to use the "pci=pcie_scan_all" parameter, but we don't
>> have that yet.
>> 
>> Link: 
>> https://lkml.kernel.org/r/CAErSpo55Q8Q=5p6_+uu7ahnw+53ibvdnrxxrzrv9qnur_9e...@mail.gmail.com
>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=198057
>> Reported-and-Tested-by: Christian Zigotzky 
>> Signed-off-by: Bjorn Helgaas 
>
> Applied to pci/enumeration for v4.16.

Thanks Bjorn.

cheers

Re: [PATCH v1] PCI: Make PCI_SCAN_ALL_PCIE_DEVS work for Root as well as Downstream Ports

[Bjorn Helgaas]

On Fri, Dec 01, 2017 at 06:27:10PM -0600, Bjorn Helgaas wrote:
> From: Bjorn Helgaas 
> 
> PCIe Downstream Ports normally have only a Device 0 below them.  To
> optimize enumeration, we don't scan for other devices *unless* the
> PCI_SCAN_ALL_PCIE_DEVS flag is set by set by quirks or the
> "pci=pcie_scan_all" kernel parameter.
> 
> Previously PCI_SCAN_ALL_PCIE_DEVS only affected scanning below Switch
> Downstream Ports, not Root Ports.
> 
> But the "Nemo" system, also known as the AmigaOne X1000, has a PA Semi Root
> Port whose link leads to an AMD/ATI SB600 South Bridge.  The Root Port is a
> PCIe device, of course, but the SB600 contains only conventional PCI
> devices with no visible PCIe port.
> 
> Simplify and restructure only_one_child() so that we scan for all possible
> devices below Root Ports as well as Switch Downstream Ports when
> PCI_SCAN_ALL_PCIE_DEVS is set.
> 
> This is enough to make Nemo work with "pci=pcie_scan_all".  We would also
> like to add a quirk to set PCI_SCAN_ALL_PCIE_DEVS automatically on Nemo so
> users wouldn't have to use the "pci=pcie_scan_all" parameter, but we don't
> have that yet.
> 
> Link: 
> https://lkml.kernel.org/r/CAErSpo55Q8Q=5p6_+uu7ahnw+53ibvdnrxxrzrv9qnur_9e...@mail.gmail.com
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=198057
> Reported-and-Tested-by: Christian Zigotzky 
> Signed-off-by: Bjorn Helgaas 

Applied to pci/enumeration for v4.16.

> ---
>  drivers/pci/probe.c |   25 +++--
>  1 file changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 14e0ea1ff38b..303c0cb0550c 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -2215,22 +2215,27 @@ static unsigned next_fn(struct pci_bus *bus, struct 
> pci_dev *dev, unsigned fn)
>  
>  static int only_one_child(struct pci_bus *bus)
>  {
> - struct pci_dev *parent = bus->self;
> + struct pci_dev *bridge = bus->self;
>  
> - if (!parent || !pci_is_pcie(parent))
> + /*
> +  * Systems with unusual topologies set PCI_SCAN_ALL_PCIE_DEVS so
> +  * we scan for all possible devices, not just Device 0.
> +  */
> + if (pci_has_flag(PCI_SCAN_ALL_PCIE_DEVS))
>   return 0;
> - if (pci_pcie_type(parent) == PCI_EXP_TYPE_ROOT_PORT)
> - return 1;
>  
>   /*
> -  * PCIe downstream ports are bridges that normally lead to only a
> -  * device 0, but if PCI_SCAN_ALL_PCIE_DEVS is set, scan all
> -  * possible devices, not just device 0.  See PCIe spec r3.0,
> -  * sec 7.3.1.
> +  * A PCIe Downstream Port normally leads to a Link with only Device
> +  * 0 on it (PCIe spec r3.1, sec 7.3.1).  As an optimization, scan
> +  * only for Device 0 in that situation.
> +  *
> +  * Checking has_secondary_link is a hack to identify Downstream
> +  * Ports because sometimes Switches are configured such that the
> +  * PCIe Port Type labels are backwards.
>*/
> - if (parent->has_secondary_link &&
> - !pci_has_flag(PCI_SCAN_ALL_PCIE_DEVS))
> + if (bridge && pci_is_pcie(bridge) && bridge->has_secondary_link)
>   return 1;
> +
>   return 0;
>  }
>  
> 

[PATCH v1] PCI: Make PCI_SCAN_ALL_PCIE_DEVS work for Root as well as Downstream Ports

[Bjorn Helgaas]

From: Bjorn Helgaas 

PCIe Downstream Ports normally have only a Device 0 below them.  To
optimize enumeration, we don't scan for other devices *unless* the
PCI_SCAN_ALL_PCIE_DEVS flag is set by set by quirks or the
"pci=pcie_scan_all" kernel parameter.

Previously PCI_SCAN_ALL_PCIE_DEVS only affected scanning below Switch
Downstream Ports, not Root Ports.

But the "Nemo" system, also known as the AmigaOne X1000, has a PA Semi Root
Port whose link leads to an AMD/ATI SB600 South Bridge.  The Root Port is a
PCIe device, of course, but the SB600 contains only conventional PCI
devices with no visible PCIe port.

Simplify and restructure only_one_child() so that we scan for all possible
devices below Root Ports as well as Switch Downstream Ports when
PCI_SCAN_ALL_PCIE_DEVS is set.

This is enough to make Nemo work with "pci=pcie_scan_all".  We would also
like to add a quirk to set PCI_SCAN_ALL_PCIE_DEVS automatically on Nemo so
users wouldn't have to use the "pci=pcie_scan_all" parameter, but we don't
have that yet.

Link: 
https://lkml.kernel.org/r/CAErSpo55Q8Q=5p6_+uu7ahnw+53ibvdnrxxrzrv9qnur_9e...@mail.gmail.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=198057
Reported-and-Tested-by: Christian Zigotzky 
Signed-off-by: Bjorn Helgaas 
---
 drivers/pci/probe.c |   25 +++--
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 14e0ea1ff38b..303c0cb0550c 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2215,22 +2215,27 @@ static unsigned next_fn(struct pci_bus *bus, struct 
pci_dev *dev, unsigned fn)
 
 static int only_one_child(struct pci_bus *bus)
 {
-   struct pci_dev *parent = bus->self;
+   struct pci_dev *bridge = bus->self;
 
-   if (!parent || !pci_is_pcie(parent))
+   /*
+* Systems with unusual topologies set PCI_SCAN_ALL_PCIE_DEVS so
+* we scan for all possible devices, not just Device 0.
+*/
+   if (pci_has_flag(PCI_SCAN_ALL_PCIE_DEVS))
return 0;
-   if (pci_pcie_type(parent) == PCI_EXP_TYPE_ROOT_PORT)
-   return 1;
 
/*
-* PCIe downstream ports are bridges that normally lead to only a
-* device 0, but if PCI_SCAN_ALL_PCIE_DEVS is set, scan all
-* possible devices, not just device 0.  See PCIe spec r3.0,
-* sec 7.3.1.
+* A PCIe Downstream Port normally leads to a Link with only Device
+* 0 on it (PCIe spec r3.1, sec 7.3.1).  As an optimization, scan
+* only for Device 0 in that situation.
+*
+* Checking has_secondary_link is a hack to identify Downstream
+* Ports because sometimes Switches are configured such that the
+* PCIe Port Type labels are backwards.
 */
-   if (parent->has_secondary_link &&
-   !pci_has_flag(PCI_SCAN_ALL_PCIE_DEVS))
+   if (bridge && pci_is_pcie(bridge) && bridge->has_secondary_link)
return 1;
+
return 0;
 }