PROBLEM: pcie imx6 link problem after a random number of reboot

[Ivan Grimaldi]

Hi,

  i have enabled early printk and after a random number of restart the
kernel hangs occurs later in the log (Below kernel log).

...
imx6q-pcie 1ffc000.pcie: Link up, Gen=2
imx6q-pcie 1ffc000.pcie: PCI host bridge to bus 0000:00
pci_bus 0000:00: root bus resource [io  0x1000-0xffff]
pci_bus 0000:00: root bus resource [mem 0x01000000-0x01efffff]
pci_bus 0000:00: root bus resource [bus 00-ff]
pci_bus 0000:00: scanning bus
pci 0000:00:00.0: [16c3:abcd] type 01 class 0x060400
pci 0000:00:00.0: reg 0x10: [mem 0x00000000-0x000fffff]
pci 0000:00:00.0: reg 0x38: [mem 0x00000000-0x0000ffff pref]
pci 0000:00:00.0: calling pci_fixup_ide_bases+0x0/0x4c
pci 0000:00:00.0: supports D1
pci 0000:00:00.0: PME# supported from D0 D1 D3hot D3cold
pci 0000:00:00.0: PME# disabled
pci_bus 0000:00: fixups for bus
PCI: bus0: Fast back to back transfers disabled
pci 0000:00:00.0: scanning [bus 01-01] behind bridge, pass 0
pci 0000:00:00.0: scanning [bus 00-00] behind bridge, pass 1
pci_bus 0000:01: scanning bus



IVan


2016-07-18 9:38 GMT+02:00 Richard Zhu <hongxing.zhu at nxp.com>:
> Hi Ivan:
>
>
>> -----Original Message-----
>> From: Ivan Grimaldi [mailto:grimaldi.ivan at gmail.com]
>> Sent: Friday, July 15, 2016 9:55 PM
>> To: Richard Zhu <hongxing.zhu at nxp.com>
>> Cc: r65037 at freescale.com; l.stach at pengutronix.de; linux-pci at vger.kernel.org;
>> bhelgaas at google.com; linux-arm-kernel at lists.infradead.org
>> Subject: Re: PROBLEM: pcie imx6 link problem after a random number of
>> reboot
>>
>> Hi ,
>>
>>  i have aligned pci-imx.c file with SHA
>> "b2d7a9cd3ff8ec561348267c2ef7d47b2b91e801" (same of kernel 4.6) and after
>> a random number of restart the kernel hangs (below the kernel log). From log,
>> as you see, the U-Boot haven't problem with PCI.
> [Zhu hongxing] The link training of kernel pcie would be impacted by the the link up state of
>  the uboot pcie.
>>
>> ...
>> U-Boot 2015.01-ge2977fb-dirty (Jul 15 2016 - 11:28:42)
>>
>> CPU:   Freescale i.MX6DL rev1.1 at 792 MHz
>> Reset cause: WDOG
>>        Watchdog enabled
>> DRAM:  1 GiB
>> Flash: 96 MiB
>> MMC:   FSL_SDHC: 0
>> WARNING: Make sure the PCIe #PERST line is connected!
>>   00:01.0     - 16c3:abcd - Bridge device
>>    01:00.0    - 14e4:b242 - Network controller
>> In:    serial
>> Out:   serial
>> Err:   serial
>> Net:   FEC [PRIME]
>> Hit any key to stop autoboot:  0
>> Booting from NFS...
>> Using FEC device
>> TFTP from server 192.168.74.130; our IP address is 192.168.74.235 Filename
>> 'ags20.dtb'.
>> Load address: 0x12000000
>> Loading: ###
>>          3.2 MiB/s
>> done
>> Bytes transferred = 29921 (74e1 hex)
>> Using FEC device
>> TFTP from server 192.168.74.130; our IP address is 192.168.74.235 Filename
>> 'zImage'.
>> Load address: 0x12100000
>> Loading:
>> ################################################################
>> #
>>
>> ################################################################
>> #
>>
>> ################################################################
>> #
>>          ##########################################
>>          3.9 MiB/s
>> done
>> Bytes transferred = 3472120 (34faf8 hex) Kernel image @ 0x12100000
>> [ 0x000000 - 0x34faf8 ] ## Flattened Device Tree blob at 12000000
>>    Booting using the fdt blob at 0x12000000
>>    Loading Device Tree to 4f530000, end 4f53a4e0 ... OK
>>
>> Starting kernel ...
>>
> [Zhu hongxing] It seems that the kernel is hang.
> Most possible reason is that pcie register is accessed, but the clks is not configured properly.
> Can you enable the " CONFIG_EARLY_PRINTK", and debug into it?
>
>>
>>
>> Best regards
>> IVan
>>
> Snip...
>
> Best Regards
> hongxing zhu
> Linux BSP team
> Office: 86-21-28937189
> Email: hongxing.zhu at nxp.com
>