Re: iMX6q PCIe phy link never came up on kernel v4.4.x

[Roberto Fichera <kernel@tekno-soft.it>]

On 03/03/2016 10:15 AM, Richard Zhu wrote:

Hi Richard,

>> -----Original Message-----
>> From: Bjorn Helgaas [mailto:helgaas@kernel.org]
>> Sent: Thursday, March 03, 2016 3:57 AM
>> To: Roberto Fichera
>> Cc: linux-pci@vger.kernel.org; Richard Zhu; Lucas Stach
>> Subject: Re: iMX6q PCIe phy link never came up on kernel v4.4.x
>>
>> [+cc Richard, Lucas]
>>
>> On Wed, Mar 02, 2016 at 06:13:11PM +0100, Roberto Fichera wrote:
>>> On 03/01/2016 07:47 PM, Roberto Fichera wrote:
>>>
>>> Sorry guy if I push a little bit about this, I've added some debugging code
>> regarding my issue:
>>> [    0.557268] imx6q-pcie 1ffc000.pcie: phy link never came up
>>> [    0.557290] imx6q-pcie 1ffc000.pcie: LTSSM current state: 0x3
>> (S_POLL_COMPLIANCE)
>>> [    0.557304] imx6q-pcie 1ffc000.pcie: PIPE transmit K indication: 1
>>> [    0.557318] imx6q-pcie 1ffc000.pcie: PIPE Transmit data: 0x4abc
>>> [    0.557332] imx6q-pcie 1ffc000.pcie: Receiver is receiving logical idle: no
>>> [    0.557345] imx6q-pcie 1ffc000.pcie: Second symbol is also idle (16-bit PHY
>> interface only): no
>>> [    0.557360] imx6q-pcie 1ffc000.pcie: Currently receiving k237 (PAD) in
>> place of link number: no
>>> [    0.557372] imx6q-pcie 1ffc000.pcie: Currently receiving k237 (PAD) in
>> place of lane number: no
>>> [    0.557385] imx6q-pcie 1ffc000.pcie: Link control bits advertised by link
>> partner: 0xa
>>> [    0.557398] imx6q-pcie 1ffc000.pcie: Receiver detected lane reversal: no
>>> [    0.557410] imx6q-pcie 1ffc000.pcie: TS2 training sequence received: no
>>> [    0.557422] imx6q-pcie 1ffc000.pcie: TS1 training sequence received: no
>>> [    0.557434] imx6q-pcie 1ffc000.pcie: Receiver reports skip reception: no
>>> [    0.557446] imx6q-pcie 1ffc000.pcie: LTSSM reports PHY link up: no
>>> [    0.557460] imx6q-pcie 1ffc000.pcie: A skip ordered set has been
>> transmitted: no
>>> [    0.557474] imx6q-pcie 1ffc000.pcie: Link number advertised/confirmed by
>> link partner: 68
>>> [    0.557487] imx6q-pcie 1ffc000.pcie: Application request to initiate training
>> reset: no
>>> [    0.557500] imx6q-pcie 1ffc000.pcie: PIPE transmit compliance request: no
>>> [    0.557512] imx6q-pcie 1ffc000.pcie: PIPE transmit electrical idle request:
>> no
>>> [    0.557524] imx6q-pcie 1ffc000.pcie: PIPE receiver detect/loopback request:
>> no
>>> [    0.557536] imx6q-pcie 1ffc000.pcie: LTSSM-negotiated link reset: yes
>>> [    0.557547] imx6q-pcie 1ffc000.pcie: LTSSM testing for polarity reversal: no
>>> [    0.557559] imx6q-pcie 1ffc000.pcie: LTSSM performing link training: no
>>> [    0.557572] imx6q-pcie 1ffc000.pcie: LTSSM in DISABLE state; link
>> inoperable: no
>>> [    0.557583] imx6q-pcie 1ffc000.pcie: Scrambling disabled for the link: no
>>> [    0.558156] imx6q-pcie 1ffc000.pcie: PCI host bridge to bus 0000:00
>>> [    0.558179] pci_bus 0000:00: root bus resource [bus 00-ff]
>>> [    0.558197] pci_bus 0000:00: root bus resource [??? 0x01f00000-0x01f7ffff
>> flags 0x0]
>>> [    0.558212] pci_bus 0000:00: root bus resource [io  0x0000-0xffff]
>>> [    0.558226] pci_bus 0000:00: root bus resource [mem 0x01000000-
>> 0x01efffff]
>>> [    0.558346] pci 0000:00:00.0: [16c3:abcd] type 01 class 0x060400
>>> [    0.558468] pci 0000:00:00.0: reg 0x10: [mem 0x00000000-0x000fffff]
>>> [    0.558510] pci 0000:00:00.0: reg 0x38: [mem 0x00000000-0x0000ffff pref]
>>> [    0.558708] pci 0000:00:00.0: supports D1
>>> [    0.558727] pci 0000:00:00.0: PME# supported from D0 D1 D3hot D3cold
>>> [    0.559495] PCI: bus0: Fast back to back transfers disabled
>>> [    0.559834] PCI: bus1: Fast back to back transfers enabled
>>> [    0.559997] pci 0000:00:00.0: BAR 0: assigned [mem 0x01000000-0x010fffff]
>>> [    0.560025] pci 0000:00:00.0: BAR 6: assigned [mem 0x01100000-0x0110ffff
>> pref]
>>> [    0.560047] pci 0000:00:00.0: PCI bridge to [bus 01]
>>> [    0.560812] pcieport 0000:00:00.0: Signaling PME through PCIe PME
>> interrupt
>>> [    0.560837] pcie_pme 0000:00:00.0:pcie01: service driver pcie_pme loaded
>>>
>>> Any idea what's going on?
>>>
>>> Thanks in advance,
>>> Roberto Fichera.
>>>
>>>> Hi There,
>>>>
>>>> Working on a custom iMX6q board I'm getting a PCIe phy link never
>>>> came up, even if uboot seems detecting everything ok. My DTS is
>>>> enabling PCIe with
>>>>
>>>> &pcie {
>>>>     pinctrl-names = "default";
>>>>     pinctrl-0 = <&pinctrl_pcie_reset>;
>>>>     reset-gpio = <&gpio7 12 0>;
>>>>     status = "okay";
>>>> };
>>>>
>>>> The PCIe is connected to a PCIe-to-PCI TI XIO2001. The XIO2001 power
>>>> is controlled by GPIO_9 and the corresponding fixed regulator is set
>>>> as
>>>>
>>>> 		reg_pcie: regulator@4 {
>>>> 			compatible = "regulator-fixed";
>>>> 			reg = <4>;
>>>> 			pinctrl-names = "default";
>>>> 			pinctrl-0 = <&pinctrl_pcie_reg>;
>>>> 			regulator-name = "MPCIE_3V3";
>>>> 			regulator-min-microvolt = <3300000>;
>>>> 			regulator-max-microvolt = <3300000>;
>>>> 			gpio = <&gpio1 9 0>;
>>>> 			regulator-always-on;
>>>> 			enable-active-high;
>>>> 		};
>>>>
>>>> so I'd like to know if there is any other special setup to do in order to get it
>> to work on a v4.4.x kernel.
>>>> Or anyway how to debug it.
>>>>
>>>> Any suggestion?
>>>>
> [Zhu hongxing] It seems that the link down is caused by the different initialization procedure.
> Can you take a try by the previouse kernel version?
> Or, you can dump and compare the register values just before the LTSSM_ENABLE is asserted between Linux and uboot.

Which register do you need to dump?

>>>> Thanks in advance,
>>>> Roberto Fichera.
>>>>
>>>> U-Boot 2014.04-imx_v2014.04_3.14.38_6qp_beta+g6e9282c (Feb 15 2016 -
>>>> 10:02:31)
>>>>
>>>> CPU:   Freescale i.MX6Q rev1.5 at 792 MHz
>>>> CPU:   Temperature 35 C, calibration data: 0x5664d569
>>>> Reset cause: POR
>>>> Board: Janas iMX6Q (ID:e315c064140749d4)
>>>> I2C:   ready
>>>> DRAM:  2 GiB
>>>> MMC:   FSL_SDHC: 0, FSL_SDHC: 1
>>>> *** Warning - bad CRC, using default environment
>>>>
>>>>   00:01.0     - 16c3:abcd - Bridge device
>>>>    01:00.0    - 104c:8240 - Bridge device
>>>>     02:04.0   - 1397:08b4 - Network controller
>>>> In:    serial
>>>> Out:   serial
>>>> Err:   serial
>>>> Found PFUZE100! deviceid=10,revid=21 mmc1(part 0) is current device
>>>> Net:   FEC [PRIME]
>>>> Warning: failed to set MAC address
>>>>
>>>> Normal Boot
>>>> ....
>>>> ....
>>>> [    0.236141] PCI host bridge /soc/pcie@0x01000000 ranges:
>>>> [    0.236162]   No bus range found for /soc/pcie@0x01000000, using [bus
>> 00-ff]
>>>> [    0.236213]   err 0x01f00000..0x01f7ffff -> 0x01f00000
>>>> [    0.236250]    IO 0x01f80000..0x01f8ffff -> 0x00000000
>>>> [    0.236330]   MEM 0x01000000..0x01efffff -> 0x01000000
>>>> -->>> [    0.546690] imx6q-pcie 1ffc000.pcie: phy link never came up
>>>> [    0.547263] imx6q-pcie 1ffc000.pcie: PCI host bridge to bus 0000:00
>>>> [    0.547287] pci_bus 0000:00: root bus resource [bus 00-ff]
>>>> [    0.547304] pci_bus 0000:00: root bus resource [??? 0x01f00000-
>> 0x01f7ffff flags 0x0]
>>>> [    0.547321] pci_bus 0000:00: root bus resource [io  0x0000-0xffff]
>>>> [    0.547335] pci_bus 0000:00: root bus resource [mem 0x01000000-
>> 0x01efffff]
>>>> [    0.548608] PCI: bus0: Fast back to back transfers disabled
>>>> [    0.548950] PCI: bus1: Fast back to back transfers enabled
>>>> [    0.549107] pci 0000:00:00.0: BAR 0: assigned [mem 0x01000000-
>> 0x010fffff]
>>>> [    0.549137] pci 0000:00:00.0: BAR 6: assigned [mem 0x01100000-
>> 0x0110ffff pref]
>>>> [    0.549159] pci 0000:00:00.0: PCI bridge to [bus 01]
>>>> [    0.549945] pcieport 0000:00:00.0: Signaling PME through PCIe PME
>> interrupt
>>>> ...
>>>>
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