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Address mapping question

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arnaudNL:
Chris,


I told you that twice, the host interface registers are on the PCIe BAR, the host interface is not reachable from the StellarIP side, all addresses are "reserved" so you need to communicate with the PCIe BAR, through an API and a device driver... Maybe PCIe BAR is confusing you? The PCIe BAR is a value pointing to a hardware memory mapped to the system memory by the BIOS. You cannot write that directly from user space and that's why we have an API and a device driver.


In order to reset the fabric, you need to write to PCIe BAR + 0, 4fm_write_anyreg.exe PC720 0 0 1


In order to configure other stars, you are then using 4fm_write_sysreg.exe.


Best Regards,
Arnaud

arnaudNL:

Dear Chris,


Was the information sufficient, may I close the topic? Feel free to open any new topic after that.


Best Regards,
Arnaud

strusc:
I understand what BAR is, my confusion comes from your documentation of the IF star. With your comments I now understand the 2 tables in the documentation are (the Pci bar address and the 7 stellar addresses).  It's still a bit nebulous why the CID table defines a 3rd set of addresses starting at  x"00012404" but the software times out trying to get a response.

We are still having issues adding additional stars and being able to communicate with them via the stellar register reads but that will have to be another forum post.

Chris

arnaudNL:
Dear Chris,


Its not nebulous, look at the source code, you will understand nothing is implemented in the host interface star at these addresses but the designer made provision for the future with some registers configured in StellarIP, this is "reserved" as per the documentation, generally reserved means "cannot use" and therefor it is to be expected you cannot use these addresses or have expectations on how they should behave. I assume these are planned to be used to map monitoring devices on the host interface stellarIP address range, this makes perfect sense and is more flexible than adding registers to the BAR and changing the driver/API.


I hope having informed you sufficiently. And yes, feel free to open other topics for the remaining issues,


Best Regards,
Arnaud

arnaudNL:
This topic is being closed because the issue is considered as resolved by 4DSP. Feel free to create a new topic for any further inquiries.

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