linux-kernel - Re: net: stmmac: dwmac-rk: fixes for Wake-on-Lan on RK3288

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Message-ID: <CAP_ceTweCVNsLONayu6woxyK7p1975w-t0LU4VUjwkqp+1G13A@mail.gmail.com>
Date:	Thu, 16 Jun 2016 07:51:01 -0700
From:	Vincent Palatin <vpalatin@...omium.org>
To:	Giuseppe CAVALLARO <peppe.cavallaro@...com>
Cc:	netdev@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
	Andrew Lunn <andrew@...n.ch>,
	Douglas Anderson <dianders@...omium.org>,
	Heiko Stübner <heiko@...ech.de>,
	Shunqian Zheng <zhengsq@...k-chips.com>,
	David Miller <davem@...emloft.net>
Subject: Re: net: stmmac: dwmac-rk: fixes for Wake-on-Lan on RK3288

Hi Giuseppe,

On Thu, Jun 16, 2016 at 6:37 AM, Giuseppe CAVALLARO
<peppe.cavallaro@...com> wrote:
>
> Hi Vincent
>
>
> On 6/15/2016 7:04 PM, Vincent Palatin wrote:
>>
>> On Sun, Jun 12, 2016 at 11:46 PM, Giuseppe CAVALLARO
>> <peppe.cavallaro@...com> wrote:
>>>
>>> On 6/11/2016 3:00 AM, Vincent Palatin wrote:
>>>>
>>>>
>>>> In order to support Wake-On-Lan when using the RK3288 integrated MAC
>>>> (with an external RGMII PHY), we need to avoid shutting down the regulator
>>>> of the external PHY when the MAC is suspended as it's currently done in
>>>> the MAC
>>>> platform code.
>>>> As a first step, create independant callbacks for suspend/resume rather
>>>> than
>>>> re-using exit/init callbacks. So the dwmac platform driver can behave
>>>> differently
>>>> on suspend where it might skip shutting the PHY and at module unloading.
>>>> Then update the dwmac-rk driver to switch off the PHY regulator only if we
>>>> are
>>>> not planning to wake up from the LAN.
>>>> Finally add the PMT interrupt to the MAC device tree configuration, so we
>>>> can
>>>> wake up the core from it when the PHY has received the magic packet.
>>>
>>>
>>>
>>> IMO these could be sent for net-next and also other glue logic
>>> files should be reworked in order to use the new API for coherence.
>>
>>
>> Given they will have the same set of functions for exit/init and
>> suspend/resume, you mean duplicating the callbacks like this :
>> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-sti.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-sti.c
>> @@ -359,6 +359,8 @@ static int sti_dwmac_probe(struct platform_device *pdev)
>>         plat_dat->bsp_priv = dwmac;
>>         plat_dat->init = sti_dwmac_init;
>>         plat_dat->exit = sti_dwmac_exit;
>> +       plat_dat->suspend = sti_dwmac_exit;
>> +       plat_dat->resume = sti_dwmac_init;
>>         plat_dat->fix_mac_speed = data->fix_retime_src;
>>
>>         ret = sti_dwmac_init(pdev, plat_dat->bsp_priv);
>>
>> Is this anyhow useful ?
>
>
> I think this is mandatory otherwise you are not guaranteeing the PM
> stuff working on the rest of the glue-logics (not only sti); because
> init/exit calls won't be called anymore.


As mentioned in the PATCH 1/3 description: "If the driver does not
provide the suspend or resume callback, we fall
back to the old behavior trying to use exit or init. [...]"
ie.
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -411,7 +411,9 @@ static int stmmac_pltfr_suspend(struct device *dev)
        struct platform_device *pdev = to_platform_device(dev);

        ret = stmmac_suspend(dev);
-       if (priv->plat->exit)
+       if (priv->plat->suspend)
+               priv->plat->suspend(pdev, priv->plat->bsp_priv);
+       else if (priv->plat->exit)
                priv->plat->exit(pdev, priv->plat->bsp_priv);

        return ret;
@@ -430,7 +432,9 @@ static int stmmac_pltfr_resume(struct device *dev)
        struct stmmac_priv *priv = netdev_priv(ndev);
        struct platform_device *pdev = to_platform_device(dev);

-       if (priv->plat->init)
+       if (priv->plat->resume)
+               priv->plat->resume(pdev, priv->plat->bsp_priv);
+       else if (priv->plat->init)
                priv->plat->init(pdev, priv->plat->bsp_priv);

        return stmmac_resume(dev);

So I was under the impression that everything should continue working
as before for drivers only providing init/exit,
by falling back on calling ->exit() if there is no suspend() callback
initialized for the PM calls.
You think that won't work ?

>
> So I kindly ask you to
> propagate the fix and send the V3.  The implementation above is ok for
> me.
>
> peppe
>