Re: [PATCH v5 12/20] memory: mtk-smi: Add gals support

[Evan Green]

On Mon, Dec 31, 2018 at 7:58 PM Yong Wu <yong.wu@xxxxxxxxxxxx> wrote:
>
> In some SoCs like mt8183, SMI add GALS(Global Async Local Sync) module
> which can help synchronize for the modules in different clock frequency.
> It can be seen as a "asynchronous fifo". This is a example diagram:
>
>             M4U
>              |
>          ----------
>          |        |
>      gals0-rx   gals1-rx
>          |        |
>          |        |
>      gals0-tx   gals1-tx
>          |        |
>         ------------
>          SMI Common
>         ------------
>              |
>   +-----+--------+-----+- ...
>   |     |        |     |
>   |  gals-rx  gals-rx  |
>   |     |        |     |
>   |     |        |     |
>   |  gals-tx  gals-tx  |
>   |     |        |     |
> larb1 larb2   larb3  larb4
>
> GALS only help transfer the command/data while it doesn't have the
> configuring register, thus it has the special "smi" clock and doesn't
> have the "apb" clock. From the diagram above, we add "gals0" and
> "gals1" clocks for smi-common and add a "gals" clock for smi-larb.
>
> This patch adds gals clock supporting in the SMI. Note that some larbs
> may still don't have the "gals" clock like larb1 and larb4 above.
>
> This is also a preparing patch for mt8183 which has GALS.
>
> Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>

So really from a software perspective the gals are just a couple of
extra clocks that need to be turned on for certain larbs. Seems fine
to me.

Reviewed-by: Evan Green <evgreen@xxxxxxxxxxxx>