linux-kernel - Re: [PATCH v2 4/4] net: macb: Add support for suspend/resume with full power down

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Message-ID: <c844298e-d997-940f-be85-fd3442d01be5@microchip.com>
Date:   Mon, 26 Nov 2018 14:46:50 +0000
From:   <Claudiu.Beznea@...rochip.com>
To:     <harini.katakam@...inx.com>, <Nicolas.Ferre@...rochip.com>,
        <davem@...emloft.net>
CC:     <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <michal.simek@...inx.com>, <harinikatakamlinux@...il.com>,
        <appanad@...inx.com>
Subject: Re: [PATCH v2 4/4] net: macb: Add support for suspend/resume with
 full power down



On 26.11.2018 09:07, Harini Katakam wrote:
> When macb device is suspended and system is powered down, the clocks
> are removed and hence macb should be closed gracefully and restored
> upon resume. This patch does the same by switching off the net device,
> suspending phy and performing necessary cleanup of interrupts and BDs.
> Upon resume, all these are reinitialized again.
> 
> Reset of macb device is done only when GEM is not a wake device.
> Even when gem is a wake device, tx queues can be stopped and ptp device
> can be closed (tsu clock will be disabled in pm_runtime_suspend) as
> wake event detection has no dependency on this.
> 
> Signed-off-by: Kedareswara rao Appana <appanad@...inx.com>
> Signed-off-by: Harini Katakam <harini.katakam@...inx.com>
> ---
> v2 changes:
> Fixed parameter passed to phy calls.
> 
>  drivers/net/ethernet/cadence/macb_main.c | 38 ++++++++++++++++++++++++++++++--
>  1 file changed, 36 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index 4b85ad7..dcb0194 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -4249,16 +4249,33 @@ static int __maybe_unused macb_suspend(struct device *dev)
>  {
>  	struct net_device *netdev = dev_get_drvdata(dev);
>  	struct macb *bp = netdev_priv(netdev);
> +	struct macb_queue *queue = bp->queues;
> +	unsigned long flags;
> +	unsigned int q;
> +
> +	if (!netif_running(netdev))
> +		return 0;
>  
> -	netif_carrier_off(netdev);
> -	netif_device_detach(netdev);

Is it necessary to remove this from here and have it on every if branch?

>  
>  	if (bp->wol & MACB_WOL_ENABLED) {
>  		macb_writel(bp, IER, MACB_BIT(WOL));
>  		macb_writel(bp, WOL, MACB_BIT(MAG));
>  		enable_irq_wake(bp->queues[0].irq);
> +		netif_device_detach(netdev);
> +	} else {
> +		netif_device_detach(netdev);
> +		for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue)
> +			napi_disable(&queue->napi);
> +		phy_stop(netdev->phydev);
> +		phy_suspend(netdev->phydev);
> +		spin_lock_irqsave(&bp->lock, flags);
> +		macb_reset_hw(bp);
> +		spin_unlock_irqrestore(&bp->lock, flags);

In the previous version you said you encountered some crashes while
stressing this part if macb_open()/macb_close() was used in here. Could you
share the tests so that I can debug it on my side?

>  	}
>  
> +	netif_carrier_off(netdev);
> +	if (bp->ptp_info)
> +		bp->ptp_info->ptp_remove(netdev);
>  	pm_runtime_force_suspend(dev);
>  
>  	return 0;
> @@ -4268,6 +4285,11 @@ static int __maybe_unused macb_resume(struct device *dev)
>  {
>  	struct net_device *netdev = dev_get_drvdata(dev);
>  	struct macb *bp = netdev_priv(netdev);
> +	struct macb_queue *queue = bp->queues;
> +	unsigned int q;
> +
> +	if (!netif_running(netdev))
> +		return 0;
>  
>  	pm_runtime_force_resume(dev);
>  
> @@ -4275,9 +4297,21 @@ static int __maybe_unused macb_resume(struct device *dev)
>  		macb_writel(bp, IDR, MACB_BIT(WOL));
>  		macb_writel(bp, WOL, 0);
>  		disable_irq_wake(bp->queues[0].irq);
> +	} else {
> +		macb_writel(bp, NCR, MACB_BIT(MPE));

Just asking... shouldn't other registers be restored here after SoC power
is cut off?

Thank you,
Claudiu Beznea

> +		for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue)
> +			napi_enable(&queue->napi);
> +		phy_resume(netdev->phydev);
> +		phy_init_hw(netdev->phydev);
> +		phy_start(netdev->phydev);
>  	}
>  
> +	bp->macbgem_ops.mog_init_rings(bp);
> +	macb_init_hw(bp);
> +	macb_set_rx_mode(netdev);
>  	netif_device_attach(netdev);
> +	if (bp->ptp_info)
> +		bp->ptp_info->ptp_init(netdev);
>  
>  	return 0;
>  }
>