netdev - Re: [RFC PATCH 4/5] net: macb: Add support for suspend/resume with full power down

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Date:   Thu, 3 May 2018 16:50:00 +0530
From:   Harini Katakam <harinik@...inx.com>
To:     Claudiu Beznea <Claudiu.Beznea@...rochip.com>
Cc:     Nicolas Ferre <nicolas.ferre@...el.com>,
        David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, michals@...inx.com,
        appanad@...inx.com
Subject: Re: [RFC PATCH 4/5] net: macb: Add support for suspend/resume with
 full power down

Hi Claudiu,

On Thu, May 3, 2018 at 3:39 PM, Claudiu Beznea
<Claudiu.Beznea@...rochip.com> wrote:
>
>
> On 22.03.2018 15:51, harinikatakamlinux@...il.com wrote:
>> From: Harini Katakam <harinik@...inx.com>
>>
>> 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.
>
> Is this a power saving mode which shut down the core?

The Ethernet IP is suspended and a majority of the SoC is shut down, yes.

<snip>
>> +             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);
>
> Wouldn't be simple to just call macb_close() here?

<snip>
>
> Wouln't be simpler to call macb_open() here?

No, I think that would be excessive for suspend. This does just
enough to put the IP into suspend and cut off clocks.
For ex., the RX and TX buffers are not freed and allocated again
in this cycle, just the buffer descriptors.

Regards,
Harini