Re: [PATCH] i.MX6 PCIe: Fix imx6_pcie_deassert_core_reset() polarity

From: Roberto Fichera
Date: Wed Mar 30 2016 - 04:01:00 EST

On 03/29/2016 07:31 PM, Tim Harvey wrote:
> On Tue, Mar 29, 2016 at 9:44 AM, Roberto Fichera <kernel@xxxxxxxxxxxxx> wrote:
>>>
>>> Roberto,
>>>
>>> What board/platform is this and what does /proc/interrupts look like?
>> It's a custom board
>>
>> root@voneus-janas-imx6q:~# cat /proc/interrupts
>> CPU0 CPU1 CPU2 CPU3
>> 16: 936 637 2057 938 GIC 29 Edge twd
>> 17: 0 0 0 0 GPC 55 Level i.MX Timer Tick
>> 22: 247 0 0 0 GPC 26 Level 2020000.serial
>> 34: 0 0 0 0 gpio-mxc 6 Edge Factory Reset Button
>> 267: 0 0 0 0 GPC 49 Level imx_thermal
>> 272: 0 0 0 0 GPC 19 Level rtc alarm
>> 278: 0 0 0 0 GPC 2 Level sdma
>> 281: 361 0 0 0 GIC 150 Level 2188000.ethernet
>> 282: 0 0 0 0 GIC 151 Level 2188000.ethernet
>> 283: 2882 0 0 0 GPC 25 Level mmc0
>> 284: 95 0 0 0 GPC 37 Level 21a4000.i2c
>> 290: 36546 0 0 0 GPC 123 Level PCIe PME, b4xxp
>> 291: 2 0 0 0 GIC 137 Level 2101000.jr0
>> 292: 0 0 0 0 GIC 138 Level 2102000.jr1
>> IPI0: 0 0 0 0 CPU wakeup interrupts
>> IPI1: 0 0 0 0 Timer broadcast interrupts
>> IPI2: 1642 1038 1626 1781 Rescheduling interrupts
>> IPI3: 95 95 122 119 Function call interrupts
>> IPI4: 3 0 2 0 Single function call interrupts
>> IPI5: 0 0 0 0 CPU stop interrupts
>> IPI6: 0 0 0 0 IRQ work interrupts
>> IPI7: 0 0 0 0 completion interrupts
>> Err: 0
>>
>>
>>> This sounds like what would happen if the downstream interrupts on the
>>> PCIe-to-PCI bridge are not mapped properly as was the case with a
>>> board I support (in which case I had to work out a bootloader fixup
>>> that placed a non-standard interrupt-map in the device-tree for the
>>> bridge). What bridge are you using?
>> PCIe-to-PCI bridge is a Ti XIO2001 where we are using INTA/B only wired 1:1
>>
> Roberto,
>
> That's right, we've talked about your bridge on IMX community.
>
> I don't see anything in your proc/interrupts other than GPC 123 - you
> probably only had one device populated when you did that.

Yep! That was the case

> Put devices
> in all for slots then show me 'cat /proc/interrupts' as well as 'lspci
> -vv' (so that I can see what interrupt was given to pin1 and what
> interrupt that maps to on the IMX6).

GPC 123 is serving J2 and J1, and looks ok

root@voneus-janas-imx6q:~# cat /proc/interrupts
CPU0 CPU1 CPU2 CPU3
16: 7409 25043 2869 71444 GIC 29 Edge twd
17: 0 0 0 0 GPC 55 Level i.MX Timer Tick
22: 526 0 0 0 GPC 26 Level 2020000.serial
34: 0 0 0 0 gpio-mxc 6 Edge Factory Reset Button
267: 0 0 0 0 GPC 49 Level imx_thermal
272: 0 0 0 0 GPC 19 Level rtc alarm
278: 0 0 0 0 GPC 2 Level sdma
281: 8808 0 0 0 GIC 150 Level 2188000.ethernet
282: 0 0 0 0 GIC 151 Level 2188000.ethernet
283: 2529 0 0 0 GPC 25 Level mmc0
284: 95 0 0 0 GPC 37 Level 21a4000.i2c
290: 2391578 0 0 0 GPC 123 Level PCIe PME, b4xxp, b4xxp
291: 2 0 0 0 GIC 137 Level 2101000.jr0
292: 0 0 0 0 GIC 138 Level 2102000.jr1
IPI0: 0 0 0 0 CPU wakeup interrupts
IPI1: 0 0 0 0 Timer broadcast interrupts
IPI2: 1122 3838 2051 9631 Rescheduling interrupts
IPI3: 60 56 48 54 Function call interrupts
IPI4: 2 1 2 3 Single function call interrupts
IPI5: 0 0 0 0 CPU stop interrupts
IPI6: 0 0 0 0 IRQ work interrupts
IPI7: 0 0 0 0 completion interrupts
Err: 0


root@voneus-janas-imx6q:~# lspci -vv -s 02:
02:00.0 ISDN controller: Cologne Chip Designs GmbH ISDN network Controller [HFC-4S] (rev 01)
Subsystem: Cologne Chip Designs GmbH HFC-4S [OpenVox B200P / B400P]
Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr+ Stepping- SERR+ FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Interrupt: pin A routed to IRQ 290
Region 0: I/O ports at 1000 [size=8]
Region 1: Memory at 01100000 (32-bit, non-prefetchable) [size=4K]
Capabilities: [40] Power Management version 2
Flags: PMEClk- DSI+ D1+ D2+ AuxCurrent=0mA PME(D0+,D1+,D2+,D3hot+,D3cold-)
Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
Kernel driver in use: wcb4xxp
Kernel modules: wcb4xxp

02:04.0 ISDN controller: Cologne Chip Designs GmbH ISDN network Controller [HFC-4S] (rev 01)
Subsystem: Cologne Chip Designs GmbH HFC-4S [OpenVox B200P / B400P]
Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr+ Stepping- SERR+ FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Interrupt: pin A routed to IRQ 290
Region 0: I/O ports at 1008 [size=8]
Region 1: Memory at 01101000 (32-bit, non-prefetchable) [size=4K]
Capabilities: [40] Power Management version 2
Flags: PMEClk- DSI+ D1+ D2+ AuxCurrent=0mA PME(D0+,D1+,D2+,D3hot+,D3cold-)
Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
Kernel driver in use: wcb4xxp
Kernel modules: wcb4xxp


>
> Check your XIO2001 routing and insure the following for proper IRQ mapping:
> Slot12: IDSEL A28: socket INTA = XIO2001 INTA
> Slot13: IDSEL A29: socket INTA = XIO2001 INTB
> Slot14: IDSEL A30: socket INTA = XIO2001 INTC
> Slot15: IDSEL A31: socket INTA = XIO2001 INTD

After crosschecking with our hardware designer the PCB IRQ mapping is the following:

J2 : IDSEL A16: => Device 0 : socket INTA = XIO2001 INTA
J3 : IDSEL A18: => Device 2 : socket INTA = XIO2001 INTA* **(This should be INTC)*
J11: IDSEL A20: => Device 4 : socket INTA = XIO2001 INTA

The interrupt routing for J3 is wrong. The XIO2001 driver may expect Device 2 to interrupt on INTC - but it will
interrupt on INTA.

>
> The relationship between slot number of IDSEL is based on the PCI
> specification. The XIO2001 int mapping to socket mapping is based on
> Table 2 in the XIO2001 implementation guide. In my case what the
> hardware designer flipped the IDSEL mappings above such that slot12's
> idsel was hooked to A31 (so it was really slot15) etc, which created a
> non-standard mapping that required what ended up being a very time
> consuming and difficult to figure out software fixup (to say the
> least).

Yep! I have read it

>
> Tim
>