[rv_dm,dv] Avoid a fast JTAG clock #23363
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Honestly, this timeout mechanism doesn't make a huge amount of sense, but this workaround should sort things out at the rv_dm level. Signed-off-by: Rupert Swarbrick <rswarbrick@lowrisc.org>
If the JTAG clock runs much faster than the system clock then things can get a bit out of sync for DMI accesses. This is tracked in an issue in the pulp-dbg module that we vendor. Tightening the constraint slightly like this should avoid the issue that led to the problem in the first place (where the system clock was at 25MHz and the JTAG tck ran at about 100MHz). Signed-off-by: Rupert Swarbrick <rswarbrick@lowrisc.org>
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hcallahan-lowrisc
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May 30, 2024
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If the JTAG clock runs much faster than the system clock then things can get a bit out of sync for DMI accesses. This is tracked in an issue in the pulp-dbg module that we vendor.
Tightening the constraint slightly like this should avoid the issue that led to the problem in the first place (where the system clock was at 25MHz and the JTAG tck ran at about 100MHz).
The pulp-dbg issue is pulp-platform/riscv-dbg#163.