[opentitantool] Add FPGA bkdr_loader TAP definition & initial commands#30474
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[opentitantool] Add FPGA bkdr_loader TAP definition & initial commands#30474AlexJones0 wants to merge 3 commits into
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Signed-off-by: Alex Jones <alex.jones@lowrisc.org>
When we're doing lots of DMI operations, these become very noisy. They make much more sense to exist at a "Debug" logging level. Signed-off-by: Alex Jones <alex.jones@lowrisc.org>
This commit implements the initial logic for integrating the FPGA backdoor loader into OpenTitanLib & OpenTitanTool. It provides interfaces for connecting to the bkdr_loader TAP via OpenOCD, entering the backdoor loader (applying the TAP strapping and resetting), and for enumerating/discovering the target information from the CSRs. A new `opentitantool bkdr` command is implemented for using this functionality, with 3 subcommands - `enter` to enter the backdoor loader, `exit` to finish using it and take OT out of reset, and `info` to list info about the available targets (or a specific target). As part of this, there is some logic for looking up a target by its unique ID. Note that we return handles for each of the different targets which simply wrap the `BackdoorTargetInfo` - these will be extended in future commits to allow operations on the various targets. Signed-off-by: Alex Jones <alex.jones@lowrisc.org>
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Add a new
opentitantool bkdrcommand with some initial subcommands:opentitantool bkdr enter- apply the TAP strapping and reset the chip to enter into the bkdr_loader'sPRELOADmode.opentitantool bkdr exit- communicate to the bkdr_loader that we are finished loading memories and so it should enterMISSIONmode - i.e. take the system out of reset and forward JTAG to regular downstream JTAG again. This is terminal until the next reset.opentitantool bkdr info- query the bkdr_loader target information registers to determine what target memories are available via the bkdr_loader, and information about these targets.To use these commands, a definition of the FPGA bkdr_loader TAP is added to opentitanlib. OpenOCD (and any relevant JTAG configuration options) are needed for all operations except entry to communicate with the DMI in the bkdr_loader, and so the JTAG parameters are included on the base
bkdrcommand.Note:
Backdoor::Targetreturning aBackdoorTargetinstead ofBackdoorTargetInfois somewhat redundant at this point, but is kept because it is intended to be used later on as a handle to add read/write commands, which will be added by future PRs.See the commit messages for more information.