Re: [PATCH] ftgmac100: Disable HW checksum generation on AST2500

[Vijay Khemka <vijaykhemka@fb.com>]

On 10/8/19, 9:37 PM, "Benjamin Herrenschmidt" <benh@kernel.crashing.org> wrote:

    On Wed, 2019-09-11 at 14:48 +0000, Joel Stanley wrote:
    > Hi Ben,
    > 
    > On Tue, 10 Sep 2019 at 22:05, Florian Fainelli <f.fainelli@gmail.com>
    > wrote:
    > > 
    > > On 9/10/19 2:37 PM, Vijay Khemka wrote:
    > > > HW checksum generation is not working for AST2500, specially with
    > > > IPV6
    > > > over NCSI. All TCP packets with IPv6 get dropped. By disabling
    > > > this
    > > > it works perfectly fine with IPV6.
    > > > 
    > > > Verified with IPV6 enabled and can do ssh.
    > > 
    > > How about IPv4, do these packets have problem? If not, can you
    > > continue
    > > advertising NETIF_F_IP_CSUM but take out NETIF_F_IPV6_CSUM?
    > > 
    > > > 
    > > > Signed-off-by: Vijay Khemka <vijaykhemka@fb.com>
    > > > ---
    > > >  drivers/net/ethernet/faraday/ftgmac100.c | 5 +++--
    > > >  1 file changed, 3 insertions(+), 2 deletions(-)
    > > > 
    > > > diff --git a/drivers/net/ethernet/faraday/ftgmac100.c
    > > > b/drivers/net/ethernet/faraday/ftgmac100.c
    > > > index 030fed65393e..591c9725002b 100644
    > > > --- a/drivers/net/ethernet/faraday/ftgmac100.c
    > > > +++ b/drivers/net/ethernet/faraday/ftgmac100.c
    > > > @@ -1839,8 +1839,9 @@ static int ftgmac100_probe(struct
    > > > platform_device *pdev)
    > > >       if (priv->use_ncsi)
    > > >               netdev->hw_features |= NETIF_F_HW_VLAN_CTAG_FILTER;
    > > > 
    > > > -     /* AST2400  doesn't have working HW checksum generation */
    > > > -     if (np && (of_device_is_compatible(np, "aspeed,ast2400-
    > > > mac")))
    > > > +     /* AST2400  and AST2500 doesn't have working HW checksum
    > > > generation */
    > > > +     if (np && (of_device_is_compatible(np, "aspeed,ast2400-
    > > > mac") ||
    > > > +                of_device_is_compatible(np, "aspeed,ast2500-
    > > > mac")))
    > 
    > Do you recall under what circumstances we need to disable hardware
    > checksumming?
    
    Any news on this ? AST2400 has no HW checksum logic in HW, AST2500
    should work for IPV4 fine, we should only selectively disable it for
    IPV6.

Ben, I have already sent v2 for this with requested change which only disable 
for IPV6 in AST2500. I can send it again.
    
    Can you do an updated patch ?
    
    Cheers,
    Ben.