netdev - Re: [PATCH] Revert "ravb: add workaround for clock when resuming with WoL enabled"

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Date:   Mon, 11 Dec 2017 14:55:52 +0100
From:   "Niklas Söderlund" <niklas.soderlund@...natech.se>
To:     Geert Uytterhoeven <geert+renesas@...der.be>
Cc:     Sergei Shtylyov <sergei.shtylyov@...entembedded.com>,
        "David S . Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH] Revert "ravb: add workaround for clock when resuming
 with WoL enabled"

Hi Geert,

Thanks for your patch.

Feels good to get rid of this hack :-)

On 2017-12-11 09:54:09 +0100, Geert Uytterhoeven wrote:
> This reverts commit fbf3d034f2ff6264183cfa6845770e8cc2a986c8.
> 
> As of commit 560869100b99a3da ("clk: renesas: cpg-mssr: Restore module
> clocks during resume"), the workaround is no longer needed.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>

Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@...natech.se>

> ---
>  drivers/net/ethernet/renesas/ravb_main.c | 27 ++-------------------------
>  1 file changed, 2 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index 2b962d349f5f415b..009780df664b4a09 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> @@ -2308,32 +2308,9 @@ static int __maybe_unused ravb_resume(struct device *dev)
>  	struct ravb_private *priv = netdev_priv(ndev);
>  	int ret = 0;
>  
> -	if (priv->wol_enabled) {
> -		/* Reduce the usecount of the clock to zero and then
> -		 * restore it to its original value. This is done to force
> -		 * the clock to be re-enabled which is a workaround
> -		 * for renesas-cpg-mssr driver which do not enable clocks
> -		 * when resuming from PSCI suspend/resume.
> -		 *
> -		 * Without this workaround the driver fails to communicate
> -		 * with the hardware if WoL was enabled when the system
> -		 * entered PSCI suspend. This is due to that if WoL is enabled
> -		 * we explicitly keep the clock from being turned off when
> -		 * suspending, but in PSCI sleep power is cut so the clock
> -		 * is disabled anyhow, the clock driver is not aware of this
> -		 * so the clock is not turned back on when resuming.
> -		 *
> -		 * TODO: once the renesas-cpg-mssr suspend/resume is working
> -		 *       this clock dance should be removed.
> -		 */
> -		clk_disable(priv->clk);
> -		clk_disable(priv->clk);
> -		clk_enable(priv->clk);
> -		clk_enable(priv->clk);
> -
> -		/* Set reset mode to rearm the WoL logic */
> +	/* If WoL is enabled set reset mode to rearm the WoL logic */
> +	if (priv->wol_enabled)
>  		ravb_write(ndev, CCC_OPC_RESET, CCC);
> -	}
>  
>  	/* All register have been reset to default values.
>  	 * Restore all registers which where setup at probe time and
> -- 
> 2.7.4
> 

-- 
Regards,
Niklas Söderlund