Firmware <-> User Space Communication

JuliaComputing / xtrx_julia

XTRX LiteX/LitePCIe based design for Julia Computing

BSD 2-Clause "Simplified" License

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Firmware <-> User Space Communication #91

Closed sjkelly closed 2 years ago

sjkelly commented 2 years ago

In order to increase the sample rate, we suspect that a combination of DAC tuning for the VCTCXO and PMIC voltages will need to be adjusted. Currently the firmware controls the I2C bus. Getting data out of the firmware into a user-space readable CSR is fine as shown in https://github.com/JuliaComputing/xtrx_julia/pull/84.

However, it is not clear to me the ideal way to write a value from user space (over PCIe) into the firmware.

enjoy-digital commented 2 years ago

@sjkelly: The firmware is only configuring the I2C peripherals at startup. For user space control, the I2C could also be directly bit-banged from user space and we could just add a lock mechanism to avoid firmware/user space conflicts.