[PATCH 0/5] Modularize PCI_DW related drivers.

[PATCH 0/5] Modularize PCI_DW related drivers.

[Paul Gortmaker]

In a recent patch series that aimed to remove code related to module
unload for PCI support that was simply non modular, the discussion
led to people wanting to keep the code and push towards taking the
steps needed to support moving it towards tristate instead[1].

Here, we take step one, which is simply making the Kconfig change
and then dealing with any build fallout or modpost fallout.  What
amounts to essentially a sanity build test.  To be clear, these
have not been runtime validated; that will need to be done by those
with access to real hardware.  However, the changes are not anything
that should disrupt any existing built-in validation, so real world
users should not be impacted by this change.

We start with a smaller family of drivers; those that actively select
PCI_DW, as a nice self contained group to test the waters and see if
everyone is still good with this approach before investing more time
on a wider scale to other pci/host/ code blocks.

As such the drivers here share a dependency on having the same group
of functions exported in order to successfully complete modpost.

In addition, we have to stray outside drivers/pci to add exports
in two places; once for an ARM fault handler, and once for an OF
variable.

The pci-keystone-dw.c instance was handled separately because it
consists of two source files that need their own group of driver
specific exports above and beyond the "shared" ones.

Then we convert the Kconfig for all remaining at once; we could have
done it on a per driver basis for ease of revert if anyone really
objects, but since it would be a one line change, that seemed like
not a real concern.

Build testing was done on the linux-next tree for arm allmodconfig.

[1] https://lkml.kernel.org/r/20160108203102.GH5354@localhost

-- 

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: devicetree@vger.kernel.org
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Murali Karicheri <m-karicheri2@ti.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Stanimir Varbanov <svarbanov@mm-sol.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arm-msm@vger.kernel.org
Cc: linux-pci@vger.kernel.org


Paul Gortmaker (5):
  ARM: add EXPORT_SYMBOL of hook_fault_code for PCI host modularization
  drivers/of: add EXPORT_SYMBOL to of_irq_count
  drivers/pci: export dw syms enabling board specific PCI code to be
    tristate
  drivers/pci: make host/pci-keystone-dw.c modular
  drivers/pci: make most of the PCI_DW drivers modular

 arch/arm/mm/fault.c                |  3 ++-
 drivers/of/irq.c                   |  1 +
 drivers/pci/host/Kconfig           | 16 ++++++++--------
 drivers/pci/host/pci-keystone-dw.c | 16 +++++++++++++++-
 drivers/pci/host/pcie-designware.c |  7 +++++++
 5 files changed, 33 insertions(+), 10 deletions(-)

-- 
2.6.1

[PATCH 2/5] drivers/of: add EXPORT_SYMBOL to of_irq_count

[Paul Gortmaker]

We would like to modularize some of the PCI platform specific
support code to keep multi platform bzImage sizes in check.

However, in a couple of the files we see this:

$ git grep -l of_irq_count drivers/pci
drivers/pci/host/pci-keystone.c
drivers/pci/host/pcie-iproc-msi.c

So, we export of_irq_count so we can make headway with the
modularization goal.

Cc: Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Frank Rowand <frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Grant Likely <grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Signed-off-by: Paul Gortmaker <paul.gortmaker-CWA4WttNNZF54TAoqtyWWQ@public.gmane.org>
---
 drivers/of/irq.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 7ee21ae305ae..0d714748a571 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -449,6 +449,7 @@ int of_irq_count(struct device_node *dev)
 
 	return nr;
 }
+EXPORT_SYMBOL(of_irq_count);
 
 /**
  * of_irq_to_resource_table - Fill in resource table with node's IRQ info
-- 
2.6.1

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Re: [PATCH 2/5] drivers/of: add EXPORT_SYMBOL to of_irq_count

[Arnd Bergmann]

On Sunday 07 February 2016 19:00:41 Paul Gortmaker wrote:
> diff --git a/drivers/of/irq.c b/drivers/of/irq.c
> index 7ee21ae305ae..0d714748a571 100644
> --- a/drivers/of/irq.c
> +++ b/drivers/of/irq.c
> @@ -449,6 +449,7 @@ int of_irq_count(struct device_node *dev)
>  
>         return nr;
>  }
> +EXPORT_SYMBOL(of_irq_count);
>  
>  /**
>   * of_irq_to_resource_table - Fill in resource table with node's IRQ info
> -- 
> 

I think the drivers should be changed to call platform_irq_count() instead.

	Arnd
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Re: [PATCH 2/5] drivers/of: add EXPORT_SYMBOL to of_irq_count

[Paul Gortmaker]

[Re: [PATCH 2/5] drivers/of: add EXPORT_SYMBOL to of_irq_count] On 08/02/2016 (Mon 10:56) Arnd Bergmann wrote:

> On Sunday 07 February 2016 19:00:41 Paul Gortmaker wrote:
> > diff --git a/drivers/of/irq.c b/drivers/of/irq.c
> > index 7ee21ae305ae..0d714748a571 100644
> > --- a/drivers/of/irq.c
> > +++ b/drivers/of/irq.c
> > @@ -449,6 +449,7 @@ int of_irq_count(struct device_node *dev)
> >  
> >         return nr;
> >  }
> > +EXPORT_SYMBOL(of_irq_count);
> >  
> >  /**
> >   * of_irq_to_resource_table - Fill in resource table with node's IRQ info
> > -- 
> > 
> 
> I think the drivers should be changed to call platform_irq_count() instead.

I'll look into that and see if it works.

P.

Re: [PATCH 0/5] Modularize PCI_DW related drivers.

[Kishon Vijay Abraham I]

Hi,

On Monday 08 February 2016 05:30 AM, Paul Gortmaker wrote:
> In a recent patch series that aimed to remove code related to module
> unload for PCI support that was simply non modular, the discussion
> led to people wanting to keep the code and push towards taking the
> steps needed to support moving it towards tristate instead[1].
> 
> Here, we take step one, which is simply making the Kconfig change
> and then dealing with any build fallout or modpost fallout.  What
> amounts to essentially a sanity build test.  To be clear, these
> have not been runtime validated; that will need to be done by those
> with access to real hardware.  However, the changes are not anything
> that should disrupt any existing built-in validation, so real world
> users should not be impacted by this change.
> 
> We start with a smaller family of drivers; those that actively select
> PCI_DW, as a nice self contained group to test the waters and see if
> everyone is still good with this approach before investing more time
> on a wider scale to other pci/host/ code blocks.
> 
> As such the drivers here share a dependency on having the same group
> of functions exported in order to successfully complete modpost.
> 
> In addition, we have to stray outside drivers/pci to add exports
> in two places; once for an ARM fault handler, and once for an OF
> variable.
> 
> The pci-keystone-dw.c instance was handled separately because it
> consists of two source files that need their own group of driver
> specific exports above and beyond the "shared" ones.
> 
> Then we convert the Kconfig for all remaining at once; we could have
> done it on a per driver basis for ease of revert if anyone really
> objects, but since it would be a one line change, that seemed like
> not a real concern.
> 
> Build testing was done on the linux-next tree for arm allmodconfig.

I took these patches and gave a test with DRA7xx board. As expected there was
no issues when the driver was built-in. However when I tried to rmmod/modprobe
I got this error [2].

Thanks
Kishon

[2] -> http://pastebin.ubuntu.com/15185894/
> 
> [1] https://lkml.kernel.org/r/20160108203102.GH5354@localhost
> 

Re: [PATCH 0/5] Modularize PCI_DW related drivers.

[Arnd Bergmann]

On Wednesday 24 February 2016 11:39:26 Kishon Vijay Abraham I wrote:
> Hi,
> 
> On Monday 08 February 2016 05:30 AM, Paul Gortmaker wrote:
> > In a recent patch series that aimed to remove code related to module
> > unload for PCI support that was simply non modular, the discussion
> > led to people wanting to keep the code and push towards taking the
> > steps needed to support moving it towards tristate instead[1].
> > 
> > Here, we take step one, which is simply making the Kconfig change
> > and then dealing with any build fallout or modpost fallout.  What
> > amounts to essentially a sanity build test.  To be clear, these
> > have not been runtime validated; that will need to be done by those
> > with access to real hardware.  However, the changes are not anything
> > that should disrupt any existing built-in validation, so real world
> > users should not be impacted by this change.
> > 
> > We start with a smaller family of drivers; those that actively select
> > PCI_DW, as a nice self contained group to test the waters and see if
> > everyone is still good with this approach before investing more time
> > on a wider scale to other pci/host/ code blocks.
> > 
> > As such the drivers here share a dependency on having the same group
> > of functions exported in order to successfully complete modpost.
> > 
> > In addition, we have to stray outside drivers/pci to add exports
> > in two places; once for an ARM fault handler, and once for an OF
> > variable.
> > 
> > The pci-keystone-dw.c instance was handled separately because it
> > consists of two source files that need their own group of driver
> > specific exports above and beyond the "shared" ones.
> > 
> > Then we convert the Kconfig for all remaining at once; we could have
> > done it on a per driver basis for ease of revert if anyone really
> > objects, but since it would be a one line change, that seemed like
> > not a real concern.
> > 
> > Build testing was done on the linux-next tree for arm allmodconfig.
> 
> I took these patches and gave a test with DRA7xx board. As expected there was
> no issues when the driver was built-in. However when I tried to rmmod/modprobe
> I got this error [2].

Thanks for testing this!

> [2] -> http://pastebin.ubuntu.com/15185894/

It looks like you are hitting the BUG_ON() in ioremap_pte_range()
that checks if a virtual address already has a page table entry,
which in turn is probably a result of dw_pcie_host_init()
calling pci_remap_iospace() again for the same memory area
it has called the last time, and no cleanup done inbetween.

Could you try adding a pci_unmap_iospace() and calling that
in the device remove function? Let me know if you need help
implementing it.

	Arnd

Re: [PATCH 0/5] Modularize PCI_DW related drivers.

[Kishon Vijay Abraham I]

Hi Arnd,

On Wednesday 24 February 2016 02:34 PM, Arnd Bergmann wrote:
> On Wednesday 24 February 2016 11:39:26 Kishon Vijay Abraham I wrote:
>> Hi,
>>
>> On Monday 08 February 2016 05:30 AM, Paul Gortmaker wrote:
>>> In a recent patch series that aimed to remove code related to module
>>> unload for PCI support that was simply non modular, the discussion
>>> led to people wanting to keep the code and push towards taking the
>>> steps needed to support moving it towards tristate instead[1].
>>>
>>> Here, we take step one, which is simply making the Kconfig change
>>> and then dealing with any build fallout or modpost fallout.  What
>>> amounts to essentially a sanity build test.  To be clear, these
>>> have not been runtime validated; that will need to be done by those
>>> with access to real hardware.  However, the changes are not anything
>>> that should disrupt any existing built-in validation, so real world
>>> users should not be impacted by this change.
>>>
>>> We start with a smaller family of drivers; those that actively select
>>> PCI_DW, as a nice self contained group to test the waters and see if
>>> everyone is still good with this approach before investing more time
>>> on a wider scale to other pci/host/ code blocks.
>>>
>>> As such the drivers here share a dependency on having the same group
>>> of functions exported in order to successfully complete modpost.
>>>
>>> In addition, we have to stray outside drivers/pci to add exports
>>> in two places; once for an ARM fault handler, and once for an OF
>>> variable.
>>>
>>> The pci-keystone-dw.c instance was handled separately because it
>>> consists of two source files that need their own group of driver
>>> specific exports above and beyond the "shared" ones.
>>>
>>> Then we convert the Kconfig for all remaining at once; we could have
>>> done it on a per driver basis for ease of revert if anyone really
>>> objects, but since it would be a one line change, that seemed like
>>> not a real concern.
>>>
>>> Build testing was done on the linux-next tree for arm allmodconfig.
>>
>> I took these patches and gave a test with DRA7xx board. As expected there was
>> no issues when the driver was built-in. However when I tried to rmmod/modprobe
>> I got this error [2].
> 
> Thanks for testing this!
> 
>> [2] -> http://pastebin.ubuntu.com/15185894/
> 
> It looks like you are hitting the BUG_ON() in ioremap_pte_range()
> that checks if a virtual address already has a page table entry,
> which in turn is probably a result of dw_pcie_host_init()
> calling pci_remap_iospace() again for the same memory area
> it has called the last time, and no cleanup done inbetween.
> 
> Could you try adding a pci_unmap_iospace() and calling that
> in the device remove function? Let me know if you need help
> implementing it.

That didn't look straight forward to me :-( I'll try to see this next week. Any
help from you will make it simpler for me.

Thanks
Kishon

Re: [PATCH 0/5] Modularize PCI_DW related drivers.

[Arnd Bergmann]

On Thursday 25 February 2016 13:43:48 Kishon Vijay Abraham I wrote:
> Hi Arnd,
> 
> On Wednesday 24 February 2016 02:34 PM, Arnd Bergmann wrote:
> > On Wednesday 24 February 2016 11:39:26 Kishon Vijay Abraham I wrote:
> >> Hi,
> >>
> >> On Monday 08 February 2016 05:30 AM, Paul Gortmaker wrote:
> >>> In a recent patch series that aimed to remove code related to module
> >>> unload for PCI support that was simply non modular, the discussion
> >>> led to people wanting to keep the code and push towards taking the
> >>> steps needed to support moving it towards tristate instead[1].
> >>>
> >>> Here, we take step one, which is simply making the Kconfig change
> >>> and then dealing with any build fallout or modpost fallout.  What
> >>> amounts to essentially a sanity build test.  To be clear, these
> >>> have not been runtime validated; that will need to be done by those
> >>> with access to real hardware.  However, the changes are not anything
> >>> that should disrupt any existing built-in validation, so real world
> >>> users should not be impacted by this change.
> >>>
> >>> We start with a smaller family of drivers; those that actively select
> >>> PCI_DW, as a nice self contained group to test the waters and see if
> >>> everyone is still good with this approach before investing more time
> >>> on a wider scale to other pci/host/ code blocks.
> >>>
> >>> As such the drivers here share a dependency on having the same group
> >>> of functions exported in order to successfully complete modpost.
> >>>
> >>> In addition, we have to stray outside drivers/pci to add exports
> >>> in two places; once for an ARM fault handler, and once for an OF
> >>> variable.
> >>>
> >>> The pci-keystone-dw.c instance was handled separately because it
> >>> consists of two source files that need their own group of driver
> >>> specific exports above and beyond the "shared" ones.
> >>>
> >>> Then we convert the Kconfig for all remaining at once; we could have
> >>> done it on a per driver basis for ease of revert if anyone really
> >>> objects, but since it would be a one line change, that seemed like
> >>> not a real concern.
> >>>
> >>> Build testing was done on the linux-next tree for arm allmodconfig.
> >>
> >> I took these patches and gave a test with DRA7xx board. As expected there was
> >> no issues when the driver was built-in. However when I tried to rmmod/modprobe
> >> I got this error [2].
> > 
> > Thanks for testing this!
> > 
> >> [2] -> http://pastebin.ubuntu.com/15185894/
> > 
> > It looks like you are hitting the BUG_ON() in ioremap_pte_range()
> > that checks if a virtual address already has a page table entry,
> > which in turn is probably a result of dw_pcie_host_init()
> > calling pci_remap_iospace() again for the same memory area
> > it has called the last time, and no cleanup done inbetween.
> > 
> > Could you try adding a pci_unmap_iospace() and calling that
> > in the device remove function? Let me know if you need help
> > implementing it.
> 
> That didn't look straight forward to me :-( I'll try to see this next week. Any
> help from you will make it simpler for me.

I tried writing the function now, and I think it's actually quite easy:

void pci_unmap_iospace(const struct resource *res)
{
#if defined(PCI_IOBASE) && defined(CONFIG_MMU)
        return iounmap(PCI_IOBASE + res->start);
#endif
}

You just need to pass the same resource in here htat you pass into
pci_remap_iospace().

	Arnd

Re: [PATCH 0/5] Modularize PCI_DW related drivers.

[Kishon Vijay Abraham I]

Hi Arnd,

On Thursday 25 February 2016 02:05 PM, Arnd Bergmann wrote:
> On Thursday 25 February 2016 13:43:48 Kishon Vijay Abraham I wrote:
>> Hi Arnd,
>>
>> On Wednesday 24 February 2016 02:34 PM, Arnd Bergmann wrote:
>>> On Wednesday 24 February 2016 11:39:26 Kishon Vijay Abraham I wrote:
>>>> Hi,
>>>>
>>>> On Monday 08 February 2016 05:30 AM, Paul Gortmaker wrote:
>>>>> In a recent patch series that aimed to remove code related to module
>>>>> unload for PCI support that was simply non modular, the discussion
>>>>> led to people wanting to keep the code and push towards taking the
>>>>> steps needed to support moving it towards tristate instead[1].
>>>>>
>>>>> Here, we take step one, which is simply making the Kconfig change
>>>>> and then dealing with any build fallout or modpost fallout.  What
>>>>> amounts to essentially a sanity build test.  To be clear, these
>>>>> have not been runtime validated; that will need to be done by those
>>>>> with access to real hardware.  However, the changes are not anything
>>>>> that should disrupt any existing built-in validation, so real world
>>>>> users should not be impacted by this change.
>>>>>
>>>>> We start with a smaller family of drivers; those that actively select
>>>>> PCI_DW, as a nice self contained group to test the waters and see if
>>>>> everyone is still good with this approach before investing more time
>>>>> on a wider scale to other pci/host/ code blocks.
>>>>>
>>>>> As such the drivers here share a dependency on having the same group
>>>>> of functions exported in order to successfully complete modpost.
>>>>>
>>>>> In addition, we have to stray outside drivers/pci to add exports
>>>>> in two places; once for an ARM fault handler, and once for an OF
>>>>> variable.
>>>>>
>>>>> The pci-keystone-dw.c instance was handled separately because it
>>>>> consists of two source files that need their own group of driver
>>>>> specific exports above and beyond the "shared" ones.
>>>>>
>>>>> Then we convert the Kconfig for all remaining at once; we could have
>>>>> done it on a per driver basis for ease of revert if anyone really
>>>>> objects, but since it would be a one line change, that seemed like
>>>>> not a real concern.
>>>>>
>>>>> Build testing was done on the linux-next tree for arm allmodconfig.
>>>>
>>>> I took these patches and gave a test with DRA7xx board. As expected there was
>>>> no issues when the driver was built-in. However when I tried to rmmod/modprobe
>>>> I got this error [2].
>>>
>>> Thanks for testing this!
>>>
>>>> [2] -> http://pastebin.ubuntu.com/15185894/
>>>
>>> It looks like you are hitting the BUG_ON() in ioremap_pte_range()
>>> that checks if a virtual address already has a page table entry,
>>> which in turn is probably a result of dw_pcie_host_init()
>>> calling pci_remap_iospace() again for the same memory area
>>> it has called the last time, and no cleanup done inbetween.
>>>
>>> Could you try adding a pci_unmap_iospace() and calling that
>>> in the device remove function? Let me know if you need help
>>> implementing it.
>>
>> That didn't look straight forward to me :-( I'll try to see this next week. Any
>> help from you will make it simpler for me.
> 
> I tried writing the function now, and I think it's actually quite easy:
> 
> void pci_unmap_iospace(const struct resource *res)
> {
> #if defined(PCI_IOBASE) && defined(CONFIG_MMU)
>         return iounmap(PCI_IOBASE + res->start);
> #endif
> }
> 
> You just need to pass the same resource in here htat you pass into
> pci_remap_iospace().

I still seem to get the abort in ioremap_page_range().

Here's the patch I used [3] and here's the kernel log [4].

[3] -> http://pastebin.ubuntu.com/15241614/
[4] -> http://pastebin.ubuntu.com/15241637/

Thanks
Kishon

Re: [PATCH 0/5] Modularize PCI_DW related drivers.

[Arnd Bergmann]

On Monday 29 February 2016 14:59:35 Kishon Vijay Abraham I wrote:
> > }
> > 
> > You just need to pass the same resource in here htat you pass into
> > pci_remap_iospace().
> 
> I still seem to get the abort in ioremap_page_range().
> 
> Here's the patch I used [3] and here's the kernel log [4].
> 
> [3] -> http://pastebin.ubuntu.com/15241614/
> [4] -> http://pastebin.ubuntu.com/15241637/
> 
> 

Sorry, I'm out of ideas here. The patch looks right to me, but the problem
looks unchanged.

	Arnd

Re: [PATCH 0/5] Modularize PCI_DW related drivers.

[Murali Karicheri]

On 03/01/2016 04:35 PM, Arnd Bergmann wrote:
> On Monday 29 February 2016 14:59:35 Kishon Vijay Abraham I wrote:
>>> }
>>>
>>> You just need to pass the same resource in here htat you pass into
>>> pci_remap_iospace().
>>
>> I still seem to get the abort in ioremap_page_range().
>>
>> Here's the patch I used [3] and here's the kernel log [4].
>>
>> [3] -> http://pastebin.ubuntu.com/15241614/
>> [4] -> http://pastebin.ubuntu.com/15241637/
>>
>>
> 
> Sorry, I'm out of ideas here. The patch looks right to me, but the problem
> looks unchanged.
> 
> 	Arnd
> 

Was there any progress since this last response from Arnd? or is it a TBD?

-- 
Murali Karicheri
Linux Kernel, Keystone