From: kishon@ti•com (Kishon Vijay Abraham I)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 0/5] Modularize PCI_DW related drivers.
Date: Mon, 29 Feb 2016 14:59:35 +0530 [thread overview]
Message-ID: <56D40F7F.5060204@ti.com> (raw)
In-Reply-To: <2837386.VTD89bjPJz@wuerfel>
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
next prev parent reply other threads:[~2016-02-29 9:29 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-08 0:00 [PATCH 0/5] Modularize PCI_DW related drivers Paul Gortmaker
2016-02-08 0:00 ` [PATCH 1/5] ARM: add EXPORT_SYMBOL of hook_fault_code for PCI host modularization Paul Gortmaker
2016-02-08 9:53 ` Arnd Bergmann
2016-02-08 16:39 ` Paul Gortmaker
2016-02-08 17:27 ` Russell King - ARM Linux
2016-02-08 17:34 ` Russell King - ARM Linux
2016-02-08 0:00 ` [PATCH 4/5] drivers/pci: make host/pci-keystone-dw.c modular Paul Gortmaker
2016-02-08 9:59 ` Arnd Bergmann
2016-02-08 15:53 ` Paul Gortmaker
2016-02-08 19:03 ` Murali Karicheri
2016-02-24 6:09 ` [PATCH 0/5] Modularize PCI_DW related drivers Kishon Vijay Abraham I
2016-02-24 9:04 ` Arnd Bergmann
2016-02-25 8:13 ` Kishon Vijay Abraham I
2016-02-25 8:35 ` Arnd Bergmann
2016-02-29 9:29 ` Kishon Vijay Abraham I [this message]
2016-03-01 21:35 ` Arnd Bergmann
2016-03-15 20:50 ` Murali Karicheri
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