[PATCH v1 03/10] ufs: host: mediatek: Add memory barrier for ref-clk control

[Peter Wang (王信友)]

On Wed, 2025-07-16 at 08:26 -0700, Bart Van Assche wrote:
> 
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> 
> On 7/15/25 11:25 PM, peter.wang at mediatek.com wrote:
> > +     /*
> > +      * Make sure that ref-clk on/off control register
> > +      * is writed done before read it.
> > +      */
> > +     mb();
> 
> A memory barrier doesn't guarantee that an MMIO write has been
> completed. A memory barrier enforces ordering of MMIO writes but does
> not guarantee completion of MMIO writes. What you need is an MMIO
> read.
> See e.g. commit 4bf3855497b6 ("scsi: ufs: core: Perform read back
> after
> disabling UIC_COMMAND_COMPL").
> 
> Bart.


Hi Bart,

Understood, this seems to be unnecessary code and will be removed
in the next version.

Thanks.
Peter