[PATCH 2/3] Add hook for BSP to act when time is set

[Chris Johns]

On 4/10/19 3:10 pm, Sebastian Huber wrote:
> On 04/10/2019 04:44, Chris Johns wrote:
>> Is this only useful for virtual BSPs and is it always a requirement to implement
>> this call in those environments?
>>
>> Would this call be useful to a non-virtual BSP, for example one with a battery
>> backed RTC device?
>>
>> Would a hook API along the lines of ....
>>
>> typedef int (*_TOD_Set_Handler)(const struct timespec *tod);
>>   _TOD_Set_Handler _TOD_Set_hook(_TOD_Set_Handler handler);
>>
>> ... be more flexible?
> 
> Yes, I think this should be generalized to allow RTC drivers to use this API as
> well. I think it should be possible to install (and remove) more than one hook,
> e.g.
> 
> typedef enum {
>   TOD_ACTION_SET_CLOCK
> } TOD_Action;

Nice.

> typedef struct TOD_Hook {
>   Chain_Node Node;
>   int (*handler)(struct TOD_Handler *, TOD_Action, const struct timespec *);
> } TOD_Hook;

I like the simpler interface of returning the current hook and specifying those
who obtain a hook call the returned hook pointer if it is not NULL. This way we
only need to hold a single pointer and there is no complexity around locking etc
to update a list as the hook holder has to deal with that locally.

Chris