Re: [PATCH v3 3/3] of: support passing console options with stdout-path

From: Peter Hurley
Date: Thu Feb 26 2015 - 09:10:09 EST


Hi Andrew,

On 02/26/2015 08:46 AM, Andrew Lunn wrote:
> On Thu, Feb 26, 2015 at 06:55:22AM -0500, Peter Hurley wrote:
>> On 11/27/2014 12:56 PM, Leif Lindholm wrote:
>>> Support specifying console options (like with console=ttyXN,<options>)
>>> by appending them to the stdout-path property after a separating ':'.
>>>
>>> Example:
>>> stdout-path = "uart0:115200";
>>
>> This format breaks DT earlycon because libfdt doesn't recognize ':' as a
>> path terminator.
>>
>> It's simple enough to fix this directly in early_init_dt_scan_chosen_serial()
>> but perhaps it would better to teach fdt_path_offset() to recognize ':'?
>
> Hi Peter
>
> ePAPR says for stdout-path in Chosen:
>
> A string that specifies the full path to the node representing the
> device to be used for boot console output. If the character ":" is
> present in the value it terminates the path. The value may be an
> alias.
>
> So it is probably wise to implement this properly.

Sorry if I was unclear. My question was not _whether_ to fix this
for earlycon, but rather _how_.

IOW, is the ':' character accepted as a path terminator for
1. all nodes, so fix this in fdt_path_offset();
2. only chosen nodes;
3. unique to stdout-path, so fix this in early_init_dt_scan_chosen_serial()?

Regards,
Peter Hurley

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