How to force iMX6 PCIe into Gen 1 mode @ imx_4.9.88_2.0.0_ga

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How to force iMX6 PCIe into Gen 1 mode @ imx_4.9.88_2.0.0_ga

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Contributor I

Hello!

We running IMX8MQ on the imx_4.9.88_2.0.0_ga release, and we need to use PCIe GEN1 mode only
(despite the fact the link can be established in Gen2 mode)

We found a solution applicable to the older kernel which could be helpful:

https://community.nxp.com/t5/i-MX-Processors/How-to-force-iMX6-PCIe-into-Gen-1-mode/m-p/264957#M2738...

Is there any way to port this patch to the newer release?

Is there any simpler way to force the Gen1 mode?

 

The DTS param "fsl,max-link-speed <0x1>" does not help: despite the fact that the Gen2 mode is disabled the driver establishes the link in Gen2 mode

[    0.967444] imx6q-pcie 33c00000.pcie: Link: Gen2 disabled
[    0.967449] imx6q-pcie 33c00000.pcie: Link up, Gen2
[    0.968851] imx6q-pcie 33c00000.pcie: PCI host bridge to bus 0001:00
[    0.968888] pci_bus 0001:00: root bus resource [bus 00-ff]
[    0.968897] pci_bus 0001:00: root bus resource [io  0x10000-0x1ffff] (bus address [0x0000-0xffff])
[    0.968904] pci_bus 0001:00: root bus resource [mem 0x20000000-0x27efffff]
[    0.968926] pci 0001:00:00.0: [16c3:abcd] type 01 class 0x060400

 

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4 Replies

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Contributor I

Does NXP provide any PCIe calibration and/or tuning tools (like DDR calibration tool)?

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87 Views
NXP TechSupport
NXP TechSupport

We have no tool for PCIe calibration.
Sorry for the inconvenience.

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78 Views
Contributor I

Hello! 

Ok, the Errata says that the SerDes has an embedded mechanism to estimate the eye diagram:

andrewbushuev_0-1601061888223.png

 

How I can obtain the results of this mechanism in Linux?

Thanks in advance.

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98 Views
NXP TechSupport
NXP TechSupport

Sorry, we have no such solution for later BSP.

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