topic Re: PCI-E Loopback Mode in i.MX Processors

PCI-E Loopback Mode

harrytan — Tue, 06 Feb 2018 09:29:09 GMT

Hi,

I am using iMX6 Solo processor and I want to have signal sent out through PCI-E Tx lane get loopback to the Rx lane. This means that Tx and Rx lanes should have the same signal. Is this done by setting the bit 2 (Loopback_Enable) of Port Link Control Register (PCIE_PL_PLCR)? Thanks.

Re: PCI-E Loopback Mode

igorpadykov — Wed, 07 Feb 2018 02:33:01 GMT

Hi Harry

yes this bit is used as part of Local PIPE Loopback procedure usually used

during production test. NXP software BSPs do not use this procedure.

Best regards
igor
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Re: PCI-E Loopback Mode

harrytan — Thu, 08 Feb 2018 08:52:48 GMT

Hi igor,

I have enabled the Loopback_Enable bit and did not get the same signal on both Tx and Rx lanes. The data is sent from a FPGA to the iMX6 processor (Tx lane of FPGA to Rx lane of processor) and I probed on Tx lane of processor using oscilloscope. I expect to get the same signal on both lanes.

I further read bit[54] (mac_phy_txdetectrx_loop PIPE receiver detect/loopback request) of DEBUG 1 (PCIE_PL_DEBUG1) register and this bit is '0'. Does this mean that the PHY did not get loopback request? Please advice, thanks.

Re: PCI-E Loopback Mode

harrytan — Mon, 12 Feb 2018 06:43:13 GMT

Hi Igor,

Do you have any thought on this? Thanks.

Regards,

Harry

Re: PCI-E Loopback Mode

igorpadykov — Mon, 12 Feb 2018 10:04:07 GMT

Hi Harry

please look at IP vendor documentation

DesignWare Dual Mode Controller IP for PCI Express

Best regards
igor

Re: PCI-E Loopback Mode

Pavan_chate — Tue, 05 Dec 2023 14:11:42 GMT

Hi ,

I am also trying to enable the loopback of bit 2. I am using LX208A and I need to enable it by using code warrior in PBL mode.
could you please explain the detailed procedure that how you have enabled the loopback from starting onward?

Re: PCI-E Loopback Mode

Pavan_chate — Tue, 12 Dec 2023 06:30:36 GMT

Hi harrytan,

could you please explain here the procedure how you did enable the loopback and all using code warrior? I need to check the loopback in PBL mode using code warrior.

Thanks and regards,

Pavan