Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1341596 > unrolled thread

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

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  Re: [PATCH 0/5] Modularize PCI_DW related drivers. Kishon Vijay Abraham I <kishon@ti.com> - 2016-02-24 07:20 +0100
    Re: [PATCH 0/5] Modularize PCI_DW related drivers. Arnd Bergmann <arnd@arndb.de> - 2016-02-24 10:10 +0100
      Re: [PATCH 0/5] Modularize PCI_DW related drivers. Kishon Vijay Abraham I <kishon@ti.com> - 2016-02-25 09:20 +0100
        Re: [PATCH 0/5] Modularize PCI_DW related drivers. Arnd Bergmann <arnd@arndb.de> - 2016-02-25 09:40 +0100
          Re: [PATCH 0/5] Modularize PCI_DW related drivers. Kishon Vijay Abraham I <kishon@ti.com> - 2016-02-29 10:40 +0100
            Re: [PATCH 0/5] Modularize PCI_DW related drivers. Arnd Bergmann <arnd@arndb.de> - 2016-03-01 22:40 +0100

#1341596 — Re: [PATCH 0/5] Modularize PCI_DW related drivers.

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
> 

[toc] | [next] | [standalone]

#1341678

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

[toc] | [prev] | [next] | [standalone]

#1342953

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

[toc] | [prev] | [next] | [standalone]

#1342973

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

[toc] | [prev] | [next] | [standalone]

#1345605

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

[toc] | [prev] | [next] | [standalone]

#1347045

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

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web