On Mon Aug 24 2020, Vinicius Costa Gomes wrote:
> Hi Kurt,
>
> Kurt Kanzenbach <kurt@xxxxxxxxxxxxx> writes:
>
>>>> +static void hellcreek_setup_tc_mapping(struct hellcreek *hellcreek,
>>>> + struct net_device *netdev)
>>>> +{
>>>> + int i, j;
>>>> +
>>>> + /* Setup mapping between traffic classes and port queues. */
>>>> + for (i = 0; i < netdev_get_num_tc(netdev); ++i) {
>>>> + for (j = 0; j < netdev->tc_to_txq[i].count; ++j) {
>>>> + const int queue = j + netdev->tc_to_txq[i].offset;
>>>> +
>>>> + hellcreek_select_prio(hellcreek, i);
>>>> + hellcreek_write(hellcreek,
>>>> + queue << HR_PRTCCFG_PCP_TC_MAP_SHIFT,
>>>> + HR_PRTCCFG);
>>>> + }
>>>> + }
>>>> +}
>>>
>>> What other driver have you seen that does this?
>>>
>>
>> Probably none.
>>
>> With TAPRIO traffic classes and the mapping to queues can be
>> configured. The switch can also map traffic classes. That sounded like a
>> good match to me.
>
> The only reason I could think that you would need this that *right now*
> taprio has pretty glaring oversight: that in the offload parameters each entry
> 'gate_mask' reference the "Traffic Class" (i.e. bit 0 is Traffic Class
> 0), and it really should be the HW queue.
>
> I have a patch that does the conversion on taprio before talking to the
> driver. Do you think it would help you avoid doing this on the driver
> side?
I think so. As Vladimir pointed out, the driver should setup an identity
mapping which I already did by default.
Can you point me your patch?
Thanks,
Kurt
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