* Re: [PATCH] net: ethernet: ti: cpsw: Set max and min MTU sizes
[not found] <20220906113212.8680-1-alexandre.bard@netmodule.com>
@ 2023-02-03 10:23 ` Romain Naour
0 siblings, 0 replies; only message in thread
From: Romain Naour @ 2023-02-03 10:23 UTC (permalink / raw)
To: Alexandre Bard, grygorii.strashko
Cc: linux-omap, davem, edumazet, Jakub Kicinski, pabeni, ast, daniel,
hawk, john.fastabend, shaozhengchao, mw, wsa+renesas,
yangyingliang, chi.minghao, Alexandre Bard, netdev
Hello,
Adding missing ML and maintainers in Cc.
Le 06/09/2022 à 13:32, Alexandre Bard a écrit :
> These fields need to be set in order for the userspace or DSA drivers to
> change the MTU to bigger or smaller values. They default to 68 and 1500
> respectively. Since the hardware supports wider limits, it is all
> benefit to set them.
>
> Specially when connecting a DSA switch, the DSA code wants to set the
> MTU of the cpsw port to 1500 + tag size. This was failing without this
> change.
I had a similar issue with the cpsw_new driver (TI CPSW Switch Support with
switchdev):
eth0: mtu greater than device maximum
cpsw-switch 48484000.switch eth0: error -22 setting MTU to 1502 to include DSA
overhead
I did the same changes to allow setting the MTU on cpsw_new driver when used
with DSA switch.
Also I noticed that the am65-cpsw-nuss already initialize min_mtu and max_mtu [1].
[1]
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/drivers/net/ethernet/ti/am65-cpsw-nuss.c?h=linux-6.1.y#n1981
Best regards,
Romain
>
> Signed-off-by: Alexandre Bard <alexandre.bard@netmodule.com>
> ---
> drivers/net/ethernet/ti/cpsw.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
> index ed66c4d4d830..83d8c6a8a527 100644
> --- a/drivers/net/ethernet/ti/cpsw.c
> +++ b/drivers/net/ethernet/ti/cpsw.c
> @@ -1631,6 +1631,9 @@ static int cpsw_probe(struct platform_device *pdev)
>
> eth_hw_addr_set(ndev, priv->mac_addr);
>
> + ndev->min_mtu = CPSW_MIN_PACKET_SIZE;
> + ndev->max_mtu = CPSW_MAX_PACKET_SIZE;
> +
> cpsw->slaves[0].ndev = ndev;
>
> ndev->features |= NETIF_F_HW_VLAN_CTAG_FILTER | NETIF_F_HW_VLAN_CTAG_RX;
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2023-02-03 10:23 ` [PATCH] net: ethernet: ti: cpsw: Set max and min MTU sizes Romain Naour
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