[Skiboot] [PATCH] powerpc/powernv: handle OPAL_SUCCESS return in opal_sensor_read

[Stewart Smith]

Cédric Le Goater <clg at fr.ibm.com> writes:
> Currently, when a sensor value is read, the kernel calls OPAL, which in
> turn builds a message for the FSP, and waits for a message back. 
>
> The new device tree for OPAL sensors [1] adds new sensors that can be 
> read synchronously (core temperatures for instance) and that don't need 
> to wait for a response.
>
> This patch modifies the opal call to accept an OPAL_SUCCESS return value
> and cover the case above.
>
> [1] https://lists.ozlabs.org/pipermail/skiboot/2015-March/000639.html
>
> Signed-off-by: Cédric Le Goater <clg at fr.ibm.com>
> ---
>
>  We still uselessly reserve a token (for the response) and take a
>  lock, which might raise the need of a new 'opal_sensor_read_sync' 
>  call.

Actually.... why do we take a lock around the OPAL calls at all?