Re: [PATCH v2] OMAP: hwmod: Update the sysc_cache in case module context is lost

[Kevin Hilman <khilman@deeprootsystems.com>]

Rajendra Nayak <rnayak@ti.com> writes:

> Do not skip the sysc programming in the hmwod framework based
> on the cached value alone, since at times the module might have lost
> context (due to the Powerdomain in which the module belongs
> transitions to either Open Switch RET or OFF).
>
> Identifying if a module has lost context requires atleast one
> register read, and since a register read has more latency than
> a write, it makes sense to do a blind write always.
>
> Signed-off-by: Rajendra Nayak <rnayak@ti.com>
> Cc: Paul Walmsley <paul@pwsan.com>
> Cc: Benoit Cousson <b-cousson@ti.com>
> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
> Cc: Kevin Hilman <khilman@deeprootsystems.com>

Acked-by: Kevin Hilman <khilman@deeprootsystems.com>

> ---
>  arch/arm/mach-omap2/omap_hwmod.c |    7 +++----
>  1 files changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
> index 5a30658..aadd6dc 100644
> --- a/arch/arm/mach-omap2/omap_hwmod.c
> +++ b/arch/arm/mach-omap2/omap_hwmod.c
> @@ -209,10 +209,9 @@ static void _write_sysconfig(u32 v, struct omap_hwmod *oh)
>  
>  	/* XXX ensure module interface clock is up */
>  
> -	if (oh->_sysc_cache != v) {
> -		oh->_sysc_cache = v;
> -		omap_hwmod_write(v, oh, oh->class->sysc->sysc_offs);
> -	}
> +	/* Module might have lost context, always update cache and register */
> +	oh->_sysc_cache = v;
> +	omap_hwmod_write(v, oh, oh->class->sysc->sysc_offs);
>  }
>  
>  /**