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Date:   Tue, 11 May 2021 14:37:45 +0200
From:   Ansuel Smith <ansuelsmth@gmail.com>
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     Matthew Wilcox <willy@infradead.org>,
        Russell King <linux@armlinux.org.uk>,
        Jonathan Corbet <corbet@lwn.net>,
        Linus Walleij <linus.walleij@linaro.org>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Abbott Liu <liuwenliang@huawei.com>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Palmer Dabbelt <palmerdabbelt@google.com>,
        Linux Doc Mailing List <linux-doc@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] arm: Enlarge IO_SPACE_LIMIT needed for some SoC
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On Tue, May 11, 2021 at 02:30:36PM +0200, Ard Biesheuvel wrote:
> On Tue, 11 May 2021 at 14:15, Ansuel Smith <ansuelsmth@gmail.com> wrote:
> >
> > On Tue, May 11, 2021 at 06:26:28AM +0200, Ard Biesheuvel wrote:
> > > On Tue, 11 May 2021 at 04:32, Ansuel Smith <ansuelsmth@gmail.com> wrote:
> > > >
> > > > On Tue, May 11, 2021 at 03:24:29AM +0100, Matthew Wilcox wrote:
> > > > > On Tue, May 11, 2021 at 04:16:54AM +0200, Ansuel Smith wrote:
> > > > > > Ipq8064 SoC requires larger IO_SPACE_LIMIT on second and third pci port.
> > > > >
> > > > > Do you really?  I mean, yes, theoretically, I understand it, the
> > > > > hardware supports 64kB of I/O port space per root port.  But I/O
> > > > > port space is rather deprecated these days.  My laptop has precisely
> > > > > two devices with I/O ports, one with 64 bytes and the other with 32
> > > > > bytes.  Would you really suffer by allocating 16kB of I/O port
> > > > > space to each root port?
> > > >
> > > > We were talking about this in the other wrong patch. I also think this
> > > > much space looks wrong. The current ipq806x dts have this space so it's
> > > > actually broken from a long time. The only reason pci worked before was
> > > > because the pci driver didn't actually check if the settings were right.
> > > > New kernel introduced more checks and this problem showed up. (to be
> > > > more precise, the pci port are commonly used by the ath10k wifi and the
> > > > second ath10k wifi fails to init because of this problem)
> > > > If you can give me any hint on how to check if the space can be reduced
> > > > I would be very happy to investigate it.
> > > > In the driver I notice that the max buffer is set to 2k, could be this a
> > > > hint?
> > > >
> > >
> > > Could you share the output of lspci -vv from such a system?
> > >
> > > I agree with Matthew that fiddling with the size of the I/O space
> > > range probably papers over another problem, and with the odd
> > > exception, no PCIe card used on ARM systems actually uses their I/O
> > > BARs, even when they have them. (I used to carry a PCIe serial port
> > > card to UEFI plugfests because that was the only thing that would stop
> > > working if a system configured its I/O resource window incorrectly)
> >
> > Here is the output of lspci -vv
> >
> > 0000:00:00.0 PCI bridge: Qualcomm Device 0101 (prog-if 00 [Normal decode])
> >         Bus: primary=00, secondary=01, subordinate=ff, sec-latency=0
> >         I/O behind bridge: [disabled]
> >         Memory behind bridge: 08000000-081fffff [size=2M]
> >         Prefetchable memory behind bridge: [disabled]
> 
> So this a MMIO window to the endpoint
> 
> ...
> 
> >
> > 0000:01:00.0 Network controller: Qualcomm Atheros QCA9984 802.11ac Wave 2 Wireless Network Adapter
> >         Region 0: Memory at 08000000 (64-bit, non-prefetchable) [size=2M]
> 
> ... and the endpoint has a single *MMIO* BAR of size 2 MiB.
> 
> This has *nothing* to do with port I/O, which is what you are
> modifying with your patch.
> 
> Did you check that the problem exists without the patch, and that the
> patch makes it go away?
> 
>

Yes without the change to IO_SPACE_LIMIT, the ath10k driver fails to
init as it can't access the reg. Only the first pci wifi works but the
second one fails to init. By increasing the limit all comes back to
normal. What I really can't understand is if the big IO space set in the
ipq8064 dtsi was wrong from the start and the ath10k fails to init just
because is missconfigured. Any idea how to find the appropriate max IO space
for the pci? 

> 
> >         Capabilities: [40] Power Management version 3
> >                 Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
> >                 Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
> >         Capabilities: [50] MSI: Enable+ Count=1/32 Maskable+ 64bit+
> >                 Address: 000000004361bc88  Data: 0001
> >                 Masking: fffffffe  Pending: 00000000
> >         Capabilities: [70] Express (v2) Endpoint, MSI 00
> >                 DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s unlimited, L1 unlimited
> >                         ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset- SlotPowerLimit 0.000W
> >                 DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
> >                         RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop-
> >                         MaxPayload 128 bytes, MaxReadReq 128 bytes
> >                 DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr+ TransPend-
> >                 LnkCap: Port #0, Speed 5GT/s, Width x1, ASPM not supported
> >                         ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+
> >                 LnkCtl: ASPM Disabled; RCB 64 bytes, Disabled- CommClk-
> >                         ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
> >                 LnkSta: Speed 5GT/s (ok), Width x1 (ok)
> >                         TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
> >                 DevCap2: Completion Timeout: Range ABCD, TimeoutDis+ NROPrPrP- LTR+
> >                          10BitTagComp- 10BitTagReq- OBFF Not Supported, ExtFmt- EETLPPrefix-
> >                          EmergencyPowerReduction Not Supported, EmergencyPowerReductionInit-
> >                          FRS- TPHComp- ExtTPHComp-
> >                          AtomicOpsCap: 32bit- 64bit- 128bitCAS-
> >                 DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis- LTR- OBFF Disabled,
> >                          AtomicOpsCtl: ReqEn-
> >                 LnkCap2: Supported Link Speeds: 2.5-5GT/s, Crosslink- Retimer- 2Retimers- DRS-
> >                 LnkCtl2: Target Link Speed: 5GT/s, EnterCompliance- SpeedDis-
> >                          Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
> >                          Compliance De-emphasis: -6dB
> >                 LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete- EqualizationPhase1-
> >                          EqualizationPhase2- EqualizationPhase3- LinkEqualizationRequest-
> >                          Retimer- 2Retimers- CrosslinkRes: unsupported
> >         Capabilities: [100 v2] Advanced Error Reporting
> >                 UESta:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
> >                 UEMsk:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
> >                 UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
> >                 CESta:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr-
> >                 CEMsk:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
> >                 AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn-
> >                         MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap-
> >                 HeaderLog: 00000000 00000000 00000000 00000000
> >         Capabilities: [148 v1] Device Serial Number 00-00-00-00-00-00-00-00
> >         Capabilities: [158 v1] Latency Tolerance Reporting
> >                 Max snoop latency: 0ns
> >                 Max no snoop latency: 0ns
> >         Capabilities: [160 v1] L1 PM Substates
> >                 L1SubCap: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2- ASPM_L1.1- L1_PM_Substates-
> >                 L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2- ASPM_L1.1-
> >                 L1SubCtl2:
> >         Kernel driver in use: ath10k_pci
> >
> > 0001:00:00.0 PCI bridge: Qualcomm Device 0101 (prog-if 00 [Normal decode])
> >         Device tree node: /sys/firmware/devicetree/base/soc/pci@1b700000/bridge@0,0
> >         Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr+ Stepping- SERR+ FastB2B- DisINTx+
> >         Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
> >         Latency: 0, Cache Line Size: 64 bytes
> >         Interrupt: pin A routed to IRQ 46
> >         Bus: primary=00, secondary=01, subordinate=ff, sec-latency=0
> >         I/O behind bridge: [disabled]
> >         Memory behind bridge: 2e000000-2e1fffff [size=2M]
> >         Prefetchable memory behind bridge: [disabled]
> >         Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- <SERR- <PERR-
> >         BridgeCtl: Parity+ SERR+ NoISA- VGA- VGA16- MAbort- >Reset- FastB2B-
> >                 PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn-
> >         Capabilities: [40] Power Management version 3
> >                 Flags: PMEClk- DSI- D1+ D2- AuxCurrent=375mA PME(D0+,D1+,D2-,D3hot+,D3cold-)
> >                 Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
> >         Capabilities: [50] MSI: Enable+ Count=1/1 Maskable- 64bit+
> >                 Address: 00000000435e8688  Data: 0000
> >         Capabilities: [70] Express (v2) Root Port (Slot-), MSI 00
> >                 DevCap: MaxPayload 128 bytes, PhantFunc 0
> >                         ExtTag- RBE+
> >                 DevCtl: CorrErr+ NonFatalErr+ FatalErr+ UnsupReq+
> >                         RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop-
> >                         MaxPayload 128 bytes, MaxReadReq 128 bytes
> >                 DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr- TransPend-
> >                 LnkCap: Port #0, Speed 5GT/s, Width x4, ASPM L0s L1, Exit Latency L0s <1us, L1 <16us
> >                         ClockPM- Surprise- LLActRep+ BwNot+ ASPMOptComp+
> >                 LnkCtl: ASPM Disabled; RCB 64 bytes, Disabled- CommClk-
> >                         ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
> >                 LnkSta: Speed 2.5GT/s (downgraded), Width x1 (downgraded)
> >                         TrErr- Train- SlotClk+ DLActive+ BWMgmt- ABWMgmt-
> >                 RootCap: CRSVisible-
> >                 RootCtl: ErrCorrectable- ErrNon-Fatal- ErrFatal- PMEIntEna- CRSVisible-
> >                 RootSta: PME ReqID 0000, PMEStatus- PMEPending-
> >                 DevCap2: Completion Timeout: Not Supported, TimeoutDis+ NROPrPrP+ LTR-
> >                          10BitTagComp- 10BitTagReq- OBFF Not Supported, ExtFmt- EETLPPrefix-
> >                          EmergencyPowerReduction Not Supported, EmergencyPowerReductionInit-
> >                          FRS- LN System CLS Not Supported, TPHComp- ExtTPHComp- ARIFwd-
> >                          AtomicOpsCap: Routing- 32bit- 64bit- 128bitCAS-
> >                 DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis- LTR- OBFF Disabled, ARIFwd-
> >                          AtomicOpsCtl: ReqEn- EgressBlck-
> >                 LnkCap2: Supported Link Speeds: 2.5-5GT/s, Crosslink- Retimer- 2Retimers- DRS-
> >                 LnkCtl2: Target Link Speed: 2.5GT/s, EnterCompliance- SpeedDis-
> >                          Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
> >                          Compliance De-emphasis: -6dB
> >                 LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete- EqualizationPhase1-
> >                          EqualizationPhase2- EqualizationPhase3- LinkEqualizationRequest-
> >                          Retimer- 2Retimers- CrosslinkRes: unsupported
> >         Capabilities: [100 v1] Advanced Error Reporting
> >                 UESta:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
> >                 UEMsk:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
> >                 UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
> >                 CESta:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr-
> >                 CEMsk:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
> >                 AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn-
> >                         MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap-
> >                 HeaderLog: 00000000 00000000 00000000 00000000
> >                 RootCmd: CERptEn+ NFERptEn+ FERptEn+
> >                 RootSta: CERcvd- MultCERcvd- UERcvd- MultUERcvd-
> >                          FirstFatal- NonFatalMsg- FatalMsg- IntMsg 0
> >                 ErrorSrc: ERR_COR: 0000 ERR_FATAL/NONFATAL: 0000
> >         Kernel driver in use: pcieport
> >
> > 0001:01:00.0 Network controller: Qualcomm Atheros QCA9984 802.11ac Wave 2 Wireless Network Adapter
> >         Subsystem: Qualcomm Atheros Device cafe
> >         Device tree node: /sys/firmware/devicetree/base/soc/pci@1b700000/bridge@0,0/wifi@1,0
> >         Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr+ Stepping- SERR+ FastB2B- DisINTx+
> >         Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
> >         Latency: 0, Cache Line Size: 64 bytes
> >         Interrupt: pin A routed to IRQ 54
> >         Region 0: Memory at 2e000000 (64-bit, non-prefetchable) [size=2M]
> >         Capabilities: [40] Power Management version 3
> >                 Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
> >                 Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
> >         Capabilities: [50] MSI: Enable+ Count=1/32 Maskable+ 64bit+
> >                 Address: 00000000435e8688  Data: 0001
> >                 Masking: fffffffe  Pending: 00000000
> >         Capabilities: [70] Express (v2) Endpoint, MSI 00
> >                 DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s unlimited, L1 unlimited
> >                         ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset- SlotPowerLimit 0.000W
> >                 DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
> >                         RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop-
> >                         MaxPayload 128 bytes, MaxReadReq 128 bytes
> >                 DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr+ TransPend-
> >                 LnkCap: Port #0, Speed 5GT/s, Width x1, ASPM not supported
> >                         ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+
> >                 LnkCtl: ASPM Disabled; RCB 64 bytes, Disabled- CommClk-
> >                         ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
> >                 LnkSta: Speed 2.5GT/s (downgraded), Width x1 (ok)
> >                         TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
> >                 DevCap2: Completion Timeout: Range ABCD, TimeoutDis+ NROPrPrP- LTR+
> >                          10BitTagComp- 10BitTagReq- OBFF Not Supported, ExtFmt- EETLPPrefix-
> >                          EmergencyPowerReduction Not Supported, EmergencyPowerReductionInit-
> >                          FRS- TPHComp- ExtTPHComp-
> >                          AtomicOpsCap: 32bit- 64bit- 128bitCAS-
> >                 DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis- LTR- OBFF Disabled,
> >                          AtomicOpsCtl: ReqEn-
> >                 LnkCap2: Supported Link Speeds: 2.5-5GT/s, Crosslink- Retimer- 2Retimers- DRS-
> >                 LnkCtl2: Target Link Speed: 5GT/s, EnterCompliance- SpeedDis-
> >                          Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
> >                          Compliance De-emphasis: -6dB
> >                 LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete- EqualizationPhase1-
> >                          EqualizationPhase2- EqualizationPhase3- LinkEqualizationRequest-
> >                          Retimer- 2Retimers- CrosslinkRes: unsupported
> >         Capabilities: [100 v2] Advanced Error Reporting
> >                 UESta:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
> >                 UEMsk:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
> >                 UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
> >                 CESta:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr-
> >                 CEMsk:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
> >                 AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn-
> >                         MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap-
> >                 HeaderLog: 00000000 00000000 00000000 00000000
> >         Capabilities: [148 v1] Device Serial Number 00-00-00-00-00-00-00-00
> >         Capabilities: [158 v1] Latency Tolerance Reporting
> >                 Max snoop latency: 0ns
> >                 Max no snoop latency: 0ns
> >         Capabilities: [160 v1] L1 PM Substates
> >                 L1SubCap: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2- ASPM_L1.1- L1_PM_Substates-
> >                 L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2- ASPM_L1.1-
> >                 L1SubCtl2:
> >         Kernel driver in use: ath10k_pci