linux-kernel - Re: [PATCH v11 07/10] soc: mediatek: Add extra sram control

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Message-ID: <1581476161.22901.36.camel@mtksdaap41>
Date:   Wed, 12 Feb 2020 10:56:01 +0800
From:   Weiyi Lu <weiyi.lu@...iatek.com>
To:     Matthias Brugger <matthias.bgg@...il.com>
CC:     Nicolas Boichat <drinkcat@...omium.org>,
        Rob Herring <robh@...nel.org>,
        Sascha Hauer <kernel@...gutronix.de>,
        James Liao <jamesjj.liao@...iatek.com>,
        <srv_heupstream@...iatek.com>, <linux-kernel@...r.kernel.org>,
        Fan Chen <fan.chen@...iatek.com>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v11 07/10] soc: mediatek: Add extra sram control

On Tue, 2020-02-11 at 18:04 +0100, Matthias Brugger wrote:
> 
> On 20/12/2019 04:46, Weiyi Lu wrote:
> > For some power domains like vpu_core on MT8183 whose sram need to
> > do clock and internal isolation while power on/off sram.
> > We add a flag "sram_iso_ctrl" in scp_domain_data to judge if we
> > need to do the extra sram isolation control or not.
> > 
> > Signed-off-by: Weiyi Lu <weiyi.lu@...iatek.com>
> > Reviewed-by: Nicolas Boichat <drinkcat@...omium.org>
> > ---
> >  drivers/soc/mediatek/mtk-scpsys.c | 24 ++++++++++++++++++++++--
> >  1 file changed, 22 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c
> > index 32be4b3..1972726 100644
> > --- a/drivers/soc/mediatek/mtk-scpsys.c
> > +++ b/drivers/soc/mediatek/mtk-scpsys.c
> > @@ -56,6 +56,8 @@
> >  #define PWR_ON_BIT			BIT(2)
> >  #define PWR_ON_2ND_BIT			BIT(3)
> >  #define PWR_CLK_DIS_BIT			BIT(4)
> > +#define PWR_SRAM_CLKISO_BIT		BIT(5)
> > +#define PWR_SRAM_ISOINT_B_BIT		BIT(6)
> >  
> >  #define PWR_STATUS_CONN			BIT(1)
> >  #define PWR_STATUS_DISP			BIT(3)
> > @@ -86,6 +88,8 @@
> >   * @name: The domain name.
> >   * @sta_mask: The mask for power on/off status bit.
> >   * @ctl_offs: The offset for main power control register.
> > + * @sram_iso_ctrl: The flag to judge if the power domain need to do
> > + *                 the extra sram isolation control.
> >   * @sram_pdn_bits: The mask for sram power control bits.
> >   * @sram_pdn_ack_bits: The mask for sram power control acked bits.
> >   * @basic_clk_name: The basic clocks required by this power domain.
> > @@ -98,6 +102,7 @@ struct scp_domain_data {
> >  	const char *name;
> >  	u32 sta_mask;
> >  	int ctl_offs;
> > +	bool sram_iso_ctrl;
> 
> Why don't we put that into the caps variable? We have plenty of space left there
> and if needed we can bump up its value from u8 to u32.
> 

Thanks for reminding, I'll put into caps in next version.

> >  	u32 sram_pdn_bits;
> >  	u32 sram_pdn_ack_bits;
> >  	const char *basic_clk_name[MAX_CLKS];
> > @@ -233,6 +238,14 @@ static int scpsys_sram_enable(struct scp_domain *scpd, void __iomem *ctl_addr)
> >  			return ret;
> >  	}
> >  
> > +	if (scpd->data->sram_iso_ctrl)	{
> > +		val = readl(ctl_addr) | PWR_SRAM_ISOINT_B_BIT;
> > +		writel(val, ctl_addr);
> > +		udelay(1);
> > +		val &= ~PWR_SRAM_CLKISO_BIT;
> > +		writel(val, ctl_addr);
> > +	}
> > +
> >  	return 0;
> >  }
> >  
> > @@ -242,8 +255,15 @@ static int scpsys_sram_disable(struct scp_domain *scpd, void __iomem *ctl_addr)
> >  	u32 pdn_ack = scpd->data->sram_pdn_ack_bits;
> >  	int tmp;
> >  
> > -	val = readl(ctl_addr);
> > -	val |= scpd->data->sram_pdn_bits;
> > +	if (scpd->data->sram_iso_ctrl)	{
> > +		val = readl(ctl_addr) | PWR_SRAM_CLKISO_BIT;
> > +		writel(val, ctl_addr);
> > +		val &= ~PWR_SRAM_ISOINT_B_BIT;
> > +		writel(val, ctl_addr);
> > +		udelay(1);
> 
> Why do we need to wait here?
> 

It's the restriction of sram isolation for both enable and disable stage
and we've confirmed 1us is safe.

> > +	}
> > +
> > +	val = readl(ctl_addr) | scpd->data->sram_pdn_bits;
> >  	writel(val, ctl_addr);
> >  
> >  	/* Either wait until SRAM_PDN_ACK all 1 or 0 */
> > 
> 
> _______________________________________________
> Linux-mediatek mailing list
> Linux-mediatek@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-mediatek

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