Re: [PATCH] soc: imx6qp: Use GENPD_FLAG_ALWAYS_ON for PU errata

[Lucas Stach]

Am Freitag, den 13.07.2018, 13:01 +0300 schrieb Leonard Crestez:
> This is functionally identical but simpler and slightly faster.
> 
> The PU domain is turned on at boot time and never turned off. In the
> current implementation the pm core will repeatedly call power_off when
> the domain is unused and get -EBUSY back. If the domain is marked as
> "always on" instead the pm core won't even attempt to turn it off.
> 
> In theory on 6qp it is safe to turn PU off in suspend, however that is
> best accomplished with a new core flag.
> 
> Signed-off-by: Leonard Crestez <leonard.crestez@xxxxxxx>

Reviewed-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>

> ---
> Âdrivers/soc/imx/gpc.c | 8 ++------
> Â1 file changed, 2 insertions(+), 6 deletions(-)
> 
> Previous discussion:
> * https://lkml.org/lkml/2018/7/11/431
> * https://lkml.org/lkml/2018/7/10/103
> 
> Attempt at turning PU off in suspend:
> * https://lkml.org/lkml/2018/7/6/698
> 
> diff --git a/drivers/soc/imx/gpc.c b/drivers/soc/imx/gpc.c
> index faf13a0b85d6..f31978e5af20 100644
> --- a/drivers/soc/imx/gpc.c
> +++ b/drivers/soc/imx/gpc.c
> @@ -45,11 +45,10 @@ struct imx_pm_domain {
> > Â	struct clk *clk[GPC_CLK_MAX];
> > Â	int num_clks;
> > Â	unsigned int reg_offs;
> > Â	signed char cntr_pdn_bit;
> > Â	unsigned int ipg_rate_mhz;
> > -	unsigned int flags;
> Â};
> Â
> Âstatic inline struct imx_pm_domain *
> Âto_imx_pm_domain(struct generic_pm_domain *genpd)
> Â{
> @@ -60,13 +59,10 @@ static int imx6_pm_domain_power_off(struct generic_pm_domain *genpd)
> Â{
> > Â	struct imx_pm_domain *pd = to_imx_pm_domain(genpd);
> > Â	int iso, iso2sw;
> > Â	u32 val;
> Â
> > -	if (pd->flags & PGC_DOMAIN_FLAG_NO_PD)
> > -		return -EBUSY;
> -
> > Â	/* Read ISO and ISO2SW power down delays */
> > Â	regmap_read(pd->regmap, pd->reg_offs + GPC_PGC_PUPSCR_OFFS, &val);
> > Â	iso = val & 0x3f;
> > Â	iso2sw = (val >> 8) & 0x3f;
> Â
> @@ -419,12 +415,12 @@ static int imx_gpc_probe(struct platform_device *pdev)
> > Â		return ret;
> > Â	}
> Â
> > Â	/* Disable PU power down in normal operation if ERR009619 is present */
> > Â	if (of_id_data->err009619_present)
> > -		imx_gpc_domains[GPC_PGC_DOMAIN_PU].flags |=
> > -				PGC_DOMAIN_FLAG_NO_PD;
> > +		imx_gpc_domains[GPC_PGC_DOMAIN_PU].base.flags |=
> > +				GENPD_FLAG_ALWAYS_ON;
> Â
> > Â	/* Keep DISP always on if ERR006287 is present */
> > Â	if (of_id_data->err006287_present)
> > Â		imx_gpc_domains[GPC_PGC_DOMAIN_DISPLAY].base.flags |=
> > Â				GENPD_FLAG_ALWAYS_ON;