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Message-ID: <322c95f1-d42d-447d-89d1-7c61112b0cfd@tuxon.dev>
Date: Sun, 17 Dec 2023 16:34:33 +0200
From: claudiu beznea <claudiu.beznea@...on.dev>
To: Sergey Shtylyov <s.shtylyov@....ru>, davem@...emloft.net,
edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
richardcochran@...il.com, p.zabel@...gutronix.de,
yoshihiro.shimoda.uh@...esas.com, wsa+renesas@...g-engineering.com,
geert+renesas@...der.be
Cc: netdev@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
linux-kernel@...r.kernel.org,
Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH net-next v2 20/21] net: ravb: Do not apply RX CSUM
settings to hardware if the interface is down
On 16.12.2023 22:36, Sergey Shtylyov wrote:
> On 12/14/23 2:45 PM, Claudiu wrote:
>
>> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>>
>> Do not apply the RX CSUM settings to hardware if the interface is down. In
>> case runtime PM is enabled, and while the interface is down, the IP will be
>> in reset mode (as for some platforms disabling/enabling the clocks will
>> switch the IP to standby mode, which will lead to losing registers'
>
> To/From perhaps?
> And just "register".
>
>> content) and applying settings in reset mode is not an option. Instead,
>> cache the RX CSUM settings and apply them in ravb_open().
>
> Have this issue actually occurred for you?
Setting RX CSUM while the if is down? No.
>
>> Commit prepares for the addition of runtime PM.
>>
>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
> [...]
>
>> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
>> index 633346b6cd7c..9ff943dff522 100644
>> --- a/drivers/net/ethernet/renesas/ravb_main.c
>> +++ b/drivers/net/ethernet/renesas/ravb_main.c
>> @@ -1868,6 +1868,15 @@ static int ravb_open(struct net_device *ndev)
>> if (info->gptp || info->ccc_gac)
>> ravb_ptp_init(ndev, priv->pdev);
>>
>> + /* Apply features that might have been changed while the interface
>> + * was down.
>> + */
>> + if (ndev->hw_features & NETIF_F_RXCSUM) {
>
> I'm afraid this is a wrong field; we need ndev->features, no?
RX CSUM is not enabled for all ravb aware devices (see struct
ravb_hw_info::net_hw_features). We should be setting the ECMR only for
these ones. ravb_hw_info::net_hw_features is set in ndev->hw_features in
probe(). So here code checks if platforms supports RXCSUM and then below it
applies what has been requested though ndo_set_features(), if any.
>
>> + u32 val = (ndev->features & NETIF_F_RXCSUM) ? ECMR_RCSC : 0;
>> +
>> + ravb_modify(ndev, ECMR, ECMR_RCSC, val);
>> + }
>> +
>
> The ECMR setting is already done in ravb_emac_init_rcar(), no need
> to duplicate it here, I think...
Ok, it worth being moved there.
>
>> /* PHY control start */
>> error = ravb_phy_start(ndev);
>> if (error)
>> @@ -2337,6 +2346,9 @@ static void ravb_set_rx_csum(struct net_device *ndev, bool enable)
>> struct ravb_private *priv = netdev_priv(ndev);
>> unsigned long flags;
>>
>> + if (!netif_running(ndev))
>
> Racy as well...
It's also called with rtnl_mutex locked.
>
>> + return;
>> +
>
> Hm, sh_eth.c doesn't have such check -- perhaps should be fixed
> as well...
>
> [...]
>
> MBR, Sergey
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