LS1046A RGMII->SGMII PHY linux device tree customization

[kristof_tunner]

Dear all!

I have three PCB boards setup seen in the picture below. I have two ls1046a processors and they are connected via an sgmii link through a backplane. On the control board a marvell 88e1512 phy is connected to the EC2 RGMII interface of the processor which converts the rgmii->sgmii. On the DSP board this sgmii interface is connected to the lane D of the first serdes block of the processor.

kristof_tunner_0-1601616639077.png

I have setup the RCW serdes protocol bits to 3333 according to the table 31-1 of the ls1046 reference manual.

kristof_tunner_1-1601616971566.png

 My question is that how should I setup the linux device tree entries in order to get this setup work?

Thanks in advance!

Kristóf

[bpe]

SGMII is a MAC-PHY interface by it's definition. If you connect something else, the only available option is a fixed-link. In this mode, no externally connected PHY initialization is done, but the on-chip SerDes still expects that the connected device behaves as an SGMII  PHY in terms of autonegotiation. If the connected device does not respond as a PHY, the link may fail. Changes in the driver code are required to adjust for other autonegotiation options. Details can be found in LS1046ARM, Section 31.8.1

Best Regards,
Platon

[kristof_tunner]

So you mean, that, if I would like to use the PHY in this configuration(explained in my post), then I have to hack the fman driver?

[bpe]

Yes, to support  non-SGMII-PHY link partner you have to alter the driver code. Not exactly FMAN, but mEMAC driver.

Regards,
Platon

[kristof_tunner]

What is the current linux branch on which this driver can be compiled, because on branch:LSDK-20.04-V5.4-update-290520 I have an error during compilation:

/home/tunnerk/nxp/layerscape/flexbuild_lsdk2004_update_290520/packages/linux/linux/drivers/net/ethernet/freescale/sdk_fman/src/inc/wrapper/lnxwrp_fsl_fman.h:46:10: fatal error: dpaa_integration_ext.h: No such file or directory
 #include "dpaa_integration_ext.h"

 In the menuconfig I choose the "Device drivers->Network device support->Ethernet driver support->Fman support" menuconfig option as built-in to compile the driver.

Regards,

Kristóf

[kristof_tunner]

Thanks!

Do you have any relevant application notes or reference manual for this topic?

Regards,

Kristóf