linux-kernel - Re: [PATCH 4/4] soc: renesas: rcar-sysc: Fix power domain control after system resume

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Date:   Wed, 5 Dec 2018 13:21:17 -0800
From:   Simon Horman <horms@...ge.net.au>
To:     Geert Uytterhoeven <geert+renesas@...der.be>
Cc:     Magnus Damm <magnus.damm@...il.com>,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        linux-renesas-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/4] soc: renesas: rcar-sysc: Fix power domain control
 after system resume

On Wed, Dec 05, 2018 at 04:39:45PM +0100, Geert Uytterhoeven wrote:
> To control power to a power domain, the System Controller (SYSC) needs
> the corresponding interrupt source to be enabled, but masked, to prevent
> the CPU from receiving it.
> 
> Currently this is handled in the driver's probe() routine, and set up
> for every domain present, even if it will not be controlled directly by
> SYSC (CPU domains are powered through the APMU on R-Car Gen2 and later).
> 
> On R-Car Gen3, PSCI powers down the SoC during system suspend, thus
> loosing any configured interrupt state.  Hence after system resume, power
> domains not controlled through the APMU (e.g. A3IR, A3VC, A3VP) fail to
> power up.

I corrected the spelling of losing when applying this patch.

> 
> Fix this by replacing the global interrupt setup in the probe() routine
> by a domain-specific interrupt setup in rcar_sysc_power(), where the
> domain's power is actually controlled.  This brings the code more in
> line with the flowchart in the Hardware User's Manual.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
> ---
>  drivers/soc/renesas/rcar-sysc.c | 28 +++++++++-------------------
>  1 file changed, 9 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/soc/renesas/rcar-sysc.c b/drivers/soc/renesas/rcar-sysc.c
> index 123e553510e826f5..0c80fab4f8de6bc8 100644
> --- a/drivers/soc/renesas/rcar-sysc.c
> +++ b/drivers/soc/renesas/rcar-sysc.c
> @@ -105,6 +105,15 @@ static int rcar_sysc_power(const struct rcar_sysc_ch *sysc_ch, bool on)
>  
>  	spin_lock_irqsave(&rcar_sysc_lock, flags);
>  
> +	/*
> +	 * The interrupt source needs to be enabled, but masked, to prevent the
> +	 * CPU from receiving it.
> +	 */
> +	iowrite32(ioread32(rcar_sysc_base + SYSCIMR) | isr_mask,
> +		  rcar_sysc_base + SYSCIMR);
> +	iowrite32(ioread32(rcar_sysc_base + SYSCIER) | isr_mask,
> +		  rcar_sysc_base + SYSCIER);
> +
>  	iowrite32(isr_mask, rcar_sysc_base + SYSCISCR);
>  
>  	/* Submit power shutoff or resume request until it was accepted */
> @@ -324,7 +333,6 @@ static int __init rcar_sysc_pd_init(void)
>  	const struct of_device_id *match;
>  	struct rcar_pm_domains *domains;
>  	struct device_node *np;
> -	u32 syscier, syscimr;
>  	void __iomem *base;
>  	unsigned int i;
>  	int error;
> @@ -363,24 +371,6 @@ static int __init rcar_sysc_pd_init(void)
>  	domains->onecell_data.num_domains = ARRAY_SIZE(domains->domains);
>  	rcar_sysc_onecell_data = &domains->onecell_data;
>  
> -	for (i = 0, syscier = 0; i < info->num_areas; i++)
> -		syscier |= BIT(info->areas[i].isr_bit);
> -
> -	/*
> -	 * Mask all interrupt sources to prevent the CPU from receiving them.
> -	 * Make sure not to clear reserved bits that were set before.
> -	 */
> -	syscimr = ioread32(base + SYSCIMR);
> -	syscimr |= syscier;
> -	pr_debug("%pOF: syscimr = 0x%08x\n", np, syscimr);
> -	iowrite32(syscimr, base + SYSCIMR);
> -
> -	/*
> -	 * SYSC needs all interrupt sources enabled to control power.
> -	 */
> -	pr_debug("%pOF: syscier = 0x%08x\n", np, syscier);
> -	iowrite32(syscier, base + SYSCIER);
> -
>  	for (i = 0; i < info->num_areas; i++) {
>  		const struct rcar_sysc_area *area = &info->areas[i];
>  		struct rcar_sysc_pd *pd;
> -- 
> 2.17.1
>