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i.MX6 PCIe with external clock on linux kernel 4.1

Question asked by mahi on Feb 22, 2017
Latest reply on Nov 30, 2017 by jiang yaqiang

Hi Community,

 

I wondered If someone else has problems with external reference clock for PCIe with linux kernel 4.1.

 

Somewhere between kernel versions 3.14.52_1 and 4.1.15_1 the "ref_100m" clock was dropped from drivers/pci/host/pci-imx6.c. With internal clock as reference that may work, but with external reference clock it doesn't. The kernel freezes on the first time trying to read a PCIe register.

 

This issue seems to be addressed in 4.1.15_2 (where "ext_osc", "pcie_ext" and "pcie_ext_src" were introduced), but due to the lack of documentation, I could not find a working devicetree configuration with that kernel.

 

So I ended up in patching the "ref_100m" clock into the 4.1.15_1 kernel.

 

Is there any accessible information about the removal of the "ref_100m" and/or the introduction of the new clocks?

 

 

Best regards

 Martin

 

PS: I am working on a custom board with i.MX6DL.

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