Hi Sergey,
> Subject: Re: [RFC 07/12] ravb: Fillup ravb_rx_gbeth() stub
>
> On 10/8/21 8:59 PM, Sergey Shtylyov wrote:
> > On 10/8/21 9:46 AM, Biju Das wrote:
> >
> > [...]
> >>>>>>>>> Fillup ravb_rx_gbeth() function to support RZ/G2L.
> >>>>>>>>>
> >>>>>>>>> This patch also renames ravb_rcar_rx to ravb_rx_rcar to be
> >>>>>>>>> consistent with the naming convention used in sh_eth driver.
> >>>>>>>>>
> >>>>>>>>> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> >>>>>>>>> Reviewed-by: Lad Prabhakar
> >>>>>>>>> <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>[...]
> >>>>>>>>> diff --git a/drivers/net/ethernet/renesas/ravb_main.c
> >>>>>>>>> b/drivers/net/ethernet/renesas/ravb_main.c
> >>>>>>>>> index 37164a983156..42573eac82b9 100644
> >>>>>>>>> --- a/drivers/net/ethernet/renesas/ravb_main.c
> >>>>>>>>> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> >>>>>>>>> @@ -720,6 +720,23 @@ static void ravb_get_tx_tstamp(struct
> >>>>>>>>> net_device
> >>>>>>>> *ndev)
> >>>>>>>>> }
> >>>>>>>>> }
> >>>>>>>>>
> >>>>>>>>> +static void ravb_rx_csum_gbeth(struct sk_buff *skb) {
> >>>>>>>>> + u8 *hw_csum;
> >>>>>>>>> +
> >>>>>>>>> + /* The hardware checksum is contained in sizeof(__sum16) (2)
> >>>> bytes
> >>>>>>>>> + * appended to packet data
> >>>>>>>>> + */
> >>>>>>>>> + if (unlikely(skb->len < sizeof(__sum16)))
> >>>>>>>>> + return;
> >>>>>>>>> + hw_csum = skb_tail_pointer(skb) - sizeof(__sum16);
> > [...]
> >>>>> Please check the section 30.5.6.1 checksum calculation handling>
> >>>>> And figure 30.25 the field of checksum attaching field
> >>>>
> >>>> I have.
> >>>>
> >>>>> Also see Table 30.17 for checksum values for non-error conditions.
> >>>>
> >>>>> TCP/UDP/ICPM checksum is at last 2bytes.
> >>>>
> >>>> What are you arguing with then? :-)
> >>>> My point was that your code fetched the TCP/UDP/ICMP checksum
> >>>> ISO the IP checksum because it subtracts sizeof(__sum16), while
> >>>> should probably subtract sizeof(__wsum)
> >>>
> >>> Agreed. My code missed IP4 checksum result. May be we need to
> >>> extract 2 checksum info from last 4 bytes. First checksum(2bytes)
> >>> is IP4 header checksum and next checksum(2 bytes) for TCP/UDP/ICMP
> >>> and use this info finding the non error case mentioned in Table
> 30.17.
> >>>
> >>> For eg:-
> >>> IPV6 non error-condition --> "0xFFFF"-->IPV4HeaderCSum value and
> "0x0000"
> >>> TCP/UDP/ICMP CSUM value
> >>>
> >>> IPV4 non error-condition --> "0x0000"-->IPV4HeaderCSum value and
> "0x0000"
> >>> TCP/UDP/ICMP CSUM value
> >>>
> >>> Do you agree?
> >
> >> What I meant here is some thing like below, please let me know if you
> >> have any issues with this, otherwise I would like to send the patch
> with below changes.
> >>
> >> Further improvements can happen later.
> >>
> >> Please let me know.
> >>
> >> +/* Hardware checksum status */
> >> +#define IPV4_RX_CSUM_OK 0x00000000
> >> +#define IPV6_RX_CSUM_OK 0xFFFF0000
> >
> > Mhm, this should prolly come from the IP headers...
> >
> > [...]
> >> diff --git a/drivers/net/ethernet/renesas/ravb_main.c
> >> b/drivers/net/ethernet/renesas/ravb_main.c
> >> index bbb42e5328e4..d9201fbbd472 100644
> >> --- a/drivers/net/ethernet/renesas/ravb_main.c
> >> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> >> @@ -722,16 +722,18 @@ static void ravb_get_tx_tstamp(struct
> >> net_device *ndev)
> >>
> >> static void ravb_rx_csum_gbeth(struct sk_buff *skb) {
> >> - u16 *hw_csum;
> >> + u32 csum_result;
> >
> > This is not against the patch currently under investigation. :-)
> >
> >> + u8 *hw_csum;
> >>
> >> /* The hardware checksum is contained in sizeof(__sum16) (2)
> bytes
> >> * appended to packet data
> >> */
> >> - if (unlikely(skb->len < sizeof(__sum16)))
> >> + if (unlikely(skb->len < sizeof(__wsum)))
> >
> > I think this usage of __wsum is valid (I remember that I suggested
> it). We have 2 16-bit checksums here
>
> I meant "I don't think", of course. :-)
Ok will use 2 * sizeof(__sum16) instead and extract IPV4 header csum and TCP/UDP/ICMP csum result.
All error condition/unsupported cases will be passed to stack with CHECKSUM_NONE
and only non-error cases will be set as CHECKSUM_UNNCESSARY.
Does it sounds good to you?
Regards,
Biju
>
> [...]
>
> MBR, Sergey
