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

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Message-ID: <28fcf690-74cb-b7cd-a53b-e54be71457b9@gmail.com>
Date:   Tue, 11 Feb 2020 18:04:50 +0100
From:   Matthias Brugger <matthias.bgg@...il.com>
To:     Weiyi Lu <weiyi.lu@...iatek.com>,
        Nicolas Boichat <drinkcat@...omium.org>,
        Rob Herring <robh@...nel.org>,
        Sascha Hauer <kernel@...gutronix.de>
Cc:     James Liao <jamesjj.liao@...iatek.com>,
        Fan Chen <fan.chen@...iatek.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-mediatek@...ts.infradead.org, srv_heupstream@...iatek.com
Subject: Re: [PATCH v11 07/10] soc: mediatek: Add extra sram control



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.

>  	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?

> +	}
> +
> +	val = readl(ctl_addr) | scpd->data->sram_pdn_bits;
>  	writel(val, ctl_addr);
>  
>  	/* Either wait until SRAM_PDN_ACK all 1 or 0 */
>