I would like to propose a new command for U-Boot's fuse programming
functionality to address the challenges posed by the current
implementation. While the existing fuse prog command works well for
programming individual fuse values, it becomes cumbersome especially
when dealing with large-scale programming requirements.
Current Command: fuse prog [-y] <bank> <word> <hexval> [<hexval>...]
This command programs one or more fuse words starting from a specific
<bank> and <word> with the hex values given as input.
While functional, it lacks the efficiency and robustness needed for
programming a significant number of fuses or handling structured fuse
configuration data. Repeatedly specifying values for each fuse bank and
word is not only time-consuming but also prone to errors during manual
input or scripting. This approach does not leverage the ability to
process pre-structured data in memory. For users with complex
programming needs, the current method becomes an obstacle rather than a
tool.
Proposed Command: fuse writebuff
NAME
fuse writebuff - Program fuse data using a memory-based structured buffer.
SYNOPSIS
fuse writebuff <command_id> <addr>
DESCRIPTION
The fuse writebuff command provides a new method for programming fuses
by leveraging a structured buffer in memory. Instead of requiring
explicit <bank> and <word> parameters for each fuse word, this command
operates on a structured buffer in memory at <addr>, that contains all
the necessary data and programming details, allowing bulk or structured
programming in a single operation. This approach simplifies workflows,
reduces manual input, and improves flexibility for complex programming
scenarios.
PARAMETERS
• <command_id>
Specifies the programming mode or indicates how the buffer data should
be interpreted. This parameter is a u32 value that identifies the
operational context or configuration for the programming process.
Examples of command_id usage might include:
• A programming mode
• A specific interpretation of the buffer layout.
• A mode for validating the buffer before programming.
• <addr>
The starting memory address of the buffer containing the structured fuse
programming data. This parameter is of type ulong and points to a block
of memory where the programming data and any associated metadata reside.
USAGE
The fuse writebuff command reads the buffer at <addr> and interprets it
according to the specified <command_id>. The structure of the buffer
should contain all necessary details for programming fuses, such as the
values to be written to the fuse, optional metadata for validation or
programming constraints and any configuration data required for the
operation.
EXAMPLES
1. fuse writebuff 1 0x80000000
In this example:
• command_id is 1, specifying a particular programming mode or a
buffer format.
• addr is 0x80000000, pointing to the starting memory address where
the structured buffer resides.
RETURN VALUES
• 0: The operation was successful.
• Non-zero: An error occurred during the operation. Errors may include
invalid command_id, inaccessible memory at <addr>, or issues with the
buffer contents.
The corresponding function, fuse_writebuff(u32 command_id, ulong addr),
would process this data in a single invocation. This approach
significantly streamlines and simplifies workflows where fuse
programming involves predefined rules or structured data, enabling users
to prepare a struct buffer in memory that encapsulates the entire fuse
programming configuration. I believe fuse writebuff simplifies
workflows, reduces error risks, and provides the extensibility needed
for advanced usage scenarios like programming large or complex fuse
configurations.
Request for Feedback
Does this proposal look good? If so, I will start to work on an RFC
patch to implement the proposed changes.
Best regards,
Harsha Vardhan V M
[email protected]
