On 17/06/2024 20:38, Sergey Shtylyov wrote:
> On 6/15/24 1:30 PM, Paul Barker wrote:
>
>> The datasheets for all SoCs using the GbEth IP specify a maximum
>> transmission frame size of 1.5 kByte. I've confirmed through internal
>> discussions that support for 1522 byte frames has been validated, which
>> allows us to support the default MTU of 1500 bytes after reserving space
>> for the Ethernet header, frame checksums and an optional VLAN tag.
>>
>> Fixes: 2e95e08ac009 ("ravb: Add rx_max_buf_size to struct ravb_hw_info")
>> Signed-off-by: Paul Barker <paul.barker.ct@xxxxxxxxxxxxxx>
> [...]
>
> Reviewed-by: Sergey Shtylyov <s.shtylyov@xxxxxx>
>
>> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
>> index c1546b916e4e..02cbf850bd85 100644
>> --- a/drivers/net/ethernet/renesas/ravb_main.c
>> +++ b/drivers/net/ethernet/renesas/ravb_main.c
>> @@ -2664,6 +2664,7 @@ static const struct ravb_hw_info ravb_gen3_hw_info = {
>> .net_features = NETIF_F_RXCSUM,
>> .stats_len = ARRAY_SIZE(ravb_gstrings_stats),
>> .tccr_mask = TCCR_TSRQ0 | TCCR_TSRQ1 | TCCR_TSRQ2 | TCCR_TSRQ3,
>> + .tx_max_frame_size = SZ_2K,
>
> The R-Car gen3 manual says 2047... Typo? :-)
Apologies for the late response.
The maximum MTU is currently based on rx_max_frame_size which is SZ_2K
for the R-Car gen3 devices. So this should be addressed in two commits:
* This commit to address the GbEth MTU, leaving the R-Car gen3 MTU
incorrect.
* A second commit to address the R-Car gen3 MTU.
Unfortunately I have no test environment where I can properly
investigate jumbo packet behaviour with a R-Car gen3 boards so I
recommend the second commit is sent by someone who can test it fully.
Thanks,
--
Paul Barker
