From: Stefan Agner <stefan@agner.ch>
To: Leonard Crestez <leonard.crestez@nxp.com>, l.stach@pengutronix.de
Cc: lorenzo.pieralisi@arm.com, Trent Piepho <tpiepho@impinj.com>,
Richard Zhu <hongxing.zhu@nxp.com>,
linux-kernel@vger.kernel.org, jingoohan1@gmail.com,
gustavo.pimentel@synopsys.com, andrew.smirnov@gmail.com,
linux-pci@vger.kernel.org, bhelgaas@google.com
Subject: Re: [PATCH v3 2/2] PCI: imx6: limit DBI register length
Date: Wed, 28 Nov 2018 18:36:48 +0100 [thread overview]
Message-ID: <fd74de3125bf7df8789e83f2e0631157@agner.ch> (raw)
In-Reply-To: <fd07b82d2473d5d7db9826142e79b00a@agner.ch>
On 28.11.2018 13:19, Stefan Agner wrote:
> On 21.11.2018 14:47, Leonard Crestez wrote:
>> On 11/20/2018 11:28 PM, Trent Piepho wrote:
>>> On Tue, 2018-11-20 at 21:42 +0100, Stefan Agner wrote:
>>>> On 20.11.2018 20:13, Trent Piepho wrote:
>>
>>>>> It also seems to me that this doesn't need to be in the internal pci
>>>>> config access functions. The driver shouldn't be reading registers
>>>>> that don't exist anyway. It's really about trying to fix sysfs access
>>>>> to registers that don't exist. So maybe it should be done there.
>>>>
>>>> That was my first approach, see:
>>>
>>> Yes, but that just used the pci device id which applies to every IMX
>>> design.
>>>
>>> It's also not totally correct, as it seems real registers after 0x200
>>> do work on imx6, and that would prevent access to them.
>>
>> I see that Lorenzo already accepted the patch in pci/dwc:
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/pci.git/commit/?h=pci/dwc&id=f14eaec153aaebbe940ddd21e4198cc2abc927c2
>>
>> My tests show that this series breaks pci cards on 6qdl and I think it
>> should be reverted until a fix is found. Are you OK with this?
>>
>> Fixing might require an entirely different approach.
>
> I tried to reproduce this issue on Apalis iMX6 (i.MX 6Q) with a ath9k
> PCIe WiFi card, the issue you are seeing did not happen. My lspci looks
> as follows:
>
> root@ea210c63d739:/# lspci -v
> 00:00.0 PCI bridge: Synopsys, Inc. Device abcd (rev 01) (prog-if 00
> [Normal decode])
> Flags: bus master, fast devsel, latency 0, IRQ 255
> Memory at 01000000 (32-bit, non-prefetchable) [size=1M]
> Bus: primary=00, secondary=01, subordinate=ff, sec-latency=0
> Memory behind bridge: 01100000-011fffff
> [virtual] Expansion ROM at 01200000 [disabled] [size=64K]
> Capabilities: [40] Power Management version 3
> Capabilities: [50] MSI: Enable- Count=1/1 Maskable+ 64bit+
> Capabilities: [70] Express Root Port (Slot-), MSI 00
> Capabilities: [100] Advanced Error Reporting
> Capabilities: [140] Virtual Channel
> lspci: Unable to load libkmod resources: error -12
>
> 01:00.0 Network controller: Qualcomm Atheros AR928X Wireless Network
> Adapter (PCI-Express) (rev 01)
> Subsystem: Foxconn International, Inc. Device e007
> Flags: bus master, fast devsel, latency 0, IRQ 312
> Memory at 01100000 (64-bit, non-prefetchable) [size=64K]
> Capabilities: [40] Power Management version 2
> Capabilities: [50] MSI: Enable- Count=1/1 Maskable- 64bit-
> Capabilities: [60] Express Legacy Endpoint, MSI 00
> Capabilities: [90] MSI-X: Enable- Count=1 Masked-
> Capabilities: [100] Advanced Error Reporting
> Capabilities: [140] Virtual Channel
> Capabilities: [160] Device Serial Number 00-00-00-00-00-00-00-00
> Kernel driver in use: ath9k
>
>
> I did also setup a WiFi network and transmitted some packages, but I did
> not get a nobody carred message. Do you have an idea why that might be?
>
> # cat /proc/interrupts
> ...
> 312: 10967 0 0 0 GPC 123 Level
> ath9k
> ...
>
>
> Your conclusion in this thread seem reasonable, hence reverting the
> issue does. However, I still would like to reproduce the issue so I can
> make sure that future patches don't break it :-)
Hm, I realized that I need to enable CONFIG_PCIEPORTBUS and set
ath9k.use_msi=1 to get MSI for that card. However, it seems that ath9k
does not behave well in that setup. It does get interrupts, and seems to
work to some degree, but I was not successful in transmitting data over
WiFi, but that might be an entirly different thing.
However, what I noticed is that when CONFIG_PCIEPORTBUS and
CONFIG_PCI_MSI is enabled, MSI works but legacy interrupt seem not to
fire anymore. That is true for ath9k as well as e1000e (using
e1000e.IntMode=0 to force legacy). Is that a known issue/limitation with
i.MX 6 PCIe?
--
Stefan
next prev parent reply other threads:[~2018-11-28 17:36 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-20 16:56 [PATCH v3 1/2] PCI: imx6: introduce drvdata Stefan Agner
2018-11-20 16:56 ` [PATCH v3 2/2] PCI: imx6: limit DBI register length Stefan Agner
2018-11-20 18:19 ` Leonard Crestez
2018-11-20 19:13 ` Trent Piepho
2018-11-20 20:42 ` Stefan Agner
2018-11-20 21:28 ` Trent Piepho
2018-11-21 13:47 ` Leonard Crestez
2018-11-21 14:17 ` Lorenzo Pieralisi
2018-11-28 12:19 ` Stefan Agner
2018-11-28 17:36 ` Stefan Agner [this message]
2018-11-28 17:50 ` Lucas Stach
2018-11-28 17:56 ` Stefan Agner
2018-11-28 18:01 ` Leonard Crestez
2018-11-26 10:16 ` Leonard Crestez
2018-11-26 16:34 ` Trent Piepho
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