[PATCH v5] RISC-V: Update Kconfig to better handle CMDLINE

[palmer@sifive.com (Palmer Dabbelt)]

On Mon, 19 Nov 2018 14:37:40 PST (-0800), atish.patra at wdc.com wrote:
> On 11/19/18 1:10 PM, Palmer Dabbelt wrote:
>> From: Nick Kossifidis <mick@ics.forth.gr>
>>
>> Added a menu to choose how the built-in command line will be
>> used and CMDLINE_EXTEND for compatibility with FDT code.
>>
>> v2: Improved help messages, removed references to bootloader
>> and made them more descriptive. I also asked help from a
>> friend who's a language expert just in case.
>>
>> v3: This time used the corrected text
>>
>> v4: Copy the config strings from the arm32 port.
>>
>> v5: Actually copy the config strings from the arm32 port.
>
> Why not use CMDLINE_FROM_BOOTLOADER instead of CMDLINE_FALLBACK in that
> case? To my ears, CMDLINE_FROM_BOOTLOADER made more sense given the
> description. If CMDLINE_FALLBACK is retained intentionally, then it's ok.

I don't really care that much about the names, so I just picked what Nick did.  
In this case I think "fallback" is better than "from bootloader", as when the 
config is appended it's also taken from the bootloader.

If you feel strongly then you're welcome to submit a v6... :)

>
> Regards,
> Atish
>>
>> Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
>> Signed-off-by: Debbie Maliotaki <dmaliotaki@gmail.com>
>> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
>> ---
>>   arch/riscv/Kconfig | 57 +++++++++++++++++++++++++++-------------------
>>   1 file changed, 33 insertions(+), 24 deletions(-)
>>
>> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
>> index 55da93f4e818..23ac6d6f9ab2 100644
>> --- a/arch/riscv/Kconfig
>> +++ b/arch/riscv/Kconfig
>> @@ -227,39 +227,48 @@ endmenu
>>
>>   menu "Boot options"
>>
>> -config CMDLINE_BOOL
>> -	bool "Built-in kernel command line"
>> +config CMDLINE
>> +	string "Built-in kernel command line"
>>   	help
>> -	  For most platforms, it is firmware or second stage bootloader
>> -	  that by default specifies the kernel command line options.
>> -	  However, it might be necessary or advantageous to either override
>> -	  the default kernel command line or add a few extra options to it.
>> -	  For such cases, this option allows hardcoding command line options
>> -	  directly into the kernel.
>> +	  For most platforms, the arguments for the kernel's command line
>> +	  are provided at run-time, during boot. However, there are cases
>> +	  where either no arguments are being provided or the provided
>> +	  arguments are insufficient or even invalid.
>>
>> -	  For that, choose 'Y' here and fill in the extra boot parameters
>> -	  in CONFIG_CMDLINE.
>> +	  When that occurs, it is possible to define a built-in command
>> +	  line here and choose how the kernel should use it later on.
>>
>> -	  The built-in options will be concatenated to the default command
>> -	  line if CMDLINE_FORCE is set to 'N'. Otherwise, the default
>> -	  command line will be ignored and replaced by the built-in string.
>> +choice
>> +	prompt "Built-in command line usage" if CMDLINE != ""
>> +	default CMDLINE_FALLBACK
>> +	help
>> +	  Choose how the kernel will handle the provided built-in command
>> +	  line.
>>
>> -config CMDLINE
>> -	string "Built-in kernel command string"
>> -	depends on CMDLINE_BOOL
>> -	default ""
>> +config CMDLINE_FALLBACK
>> +	bool "Use bootloader kernel arguments if available"
>>   	help
>> -	  Supply command-line options at build time by entering them here.
>> +	  Use the built-in command line as fallback in case we get nothing
>> +	  during boot. This is the default behaviour.
>>
>> +config CMDLINE_EXTEND
>> +	bool "Extend bootloader kernel arguments"
>> +	help
>> +	  The command-line arguments provided during boot will be
>> +	  appended to the built-in command line. This is useful in
>> +	  cases where the provided arguments are insufficient and
>> +	  you don't want to or cannot modify them.
>> +
>>
>>   config CMDLINE_FORCE
>> -	bool "Built-in command line overrides bootloader arguments"
>> -	depends on CMDLINE_BOOL
>> +	bool "Always use the default kernel command string"
>>   	help
>> -	  Set this option to 'Y' to have the kernel ignore the bootloader
>> -	  or firmware command line.  Instead, the built-in command line
>> -	  will be used exclusively.
>> +	  Always use the built-in command line, even if we get one during
>> +	  boot. This is useful in case you need to override the provided
>> +	  command line on systems where you don't have or want control
>> +	  over it.
>>
>> -	  If you don't know what to do here, say N.
>> +endchoice
>>
>>   endmenu
>>
>>