Requesting Solution for Probably Hidden Errata (?) of PTM in i.MX 6 SoloX Sabre Development Board

[hjkim2]

I've already posted about the PTM problem of i.MX 6 Solox SDB.

Out team confirmed that PTM works on i.MX 6QuadPlus SABRE Development Board with emulated JTAG_CLK with same methodology.

By the way, we could get a Cortex-A9 PTM Trace too. Connecting J-Link JTAG Emulator to the board, we could get a normal trace from ETB. It seems that connection to JTAG port, and some stages that J-Link Commander do are important for getting PTM Trace.

And I think it's kind of hidden errata in this board. Because, its behavior is similar to PTM errata in i.MX 6 QuadPlus, but can be cleared with different method; JTAG Connection + Some Communication with J-Link Commander.

But we need to get PTM Trace without connection with J-Link JTAG Emulator. So I want to know the exact condition that makes PTM work on i.MX 6 Solox SDB.

Thank you :smileyhappy:

[jamesbone]

Hi,

Quoting from the ARM documentation link:

ARM Information Center

"The PTM compresses the trace information and exports it to a CoreSight trace capture subsystem. The CoreSight trace capture subsystem either:

• Exports the trace through a trace port. An external Trace Port Analyzer (TPA) captures the trace information.

• Writes the trace directly to an on-chip Embedded Trace Buffer (ETB). When the trace capture is complete, the trace is read out at low speed, typically using a JTAG or Serial Wire interface."

And from the schematic of i.MX 6 Solox SDB, it looks like there is no TPA provided. So we can read out the trace from ETB using JTAG or Serial Wire interface.

As we do not want to use JTAG, only way that's left is reading from ETB using Serial wire interface.

Have a great day,
TIC

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[hjkim2]

Yes. But our team want to read data from ETB just inside linux on i.MXSoloX (without JTAG or Serial Wire Interface Connection). And it's possible to dump trace file with Linux PTM driver.

But sadly, PTM doesn't work well without JTAG connection. It just output dummy data.

But after connecting J-Link JTAG Emulator and executing 'connect' command. PTM work well even after disconnecting JTAG Emulator. It seems that this connection enables something inside board and makes PTM work.

If so, is there any method to find out this condition for enabling PTM? or is it just some kind of errata like one in i.MX6Q?

Thank you :smileyhappy: