Overriding/concatenating kernel command-line with bootargs from dtb?

Nicolas Pitre nico at fluxnic.net
Fri Jun 8 17:49:20 EDT 2012

On Fri, 8 Jun 2012, Florian Fainelli wrote:

> Hi all,
> I have a specific use case, where two boards using the same SoC have different 
> UART speeds, which is something that I have specified in their corresponding 
> dts files. In order to make sure people don't mess up the configuration, I 
> prefer not to rely on the bootloader-supplied kernel-command line.
> I was kind of expecting that ARM_ATAG_DTB_COMPAT + CMDLINE_EXTEND would 
> actually concatenate the kernel command-line with the bootargs provided from 
> dtb.
> Is this something someone else would need? If so, shall we just make that 
> happen when the two config symbols mentionned above are enabled, or shall we 
> introduce a 4th kernel command line handling strategy?

The former please.  The logic in parse_tag_cmdline() needs to be 
duplicated in early_init_dt_scan_chosen().  CONFIG_CMDLINE_FORCE is 
already implemented, so only CONFIG_CMDLINE_EXTEND is missing.


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