Hello Paul,

On Mon Feb 26 2024, Paul Menzel wrote:
> Dear Kurt,
>
>
> Thank you for the patch. Some nits from my side.
>
> Am 26.02.24 um 09:51 schrieb Kurt Kanzenbach:
>> Add support for offloading MQPRIO. The hardware has four priorities as well
>> as four queues. Each queue must be a assigned with a unique priority.
>> 
>> However, the priorities are only considered in TSN Tx mode. There are two
>> TSN Tx modes. In case of MQPRIO the Qbv capability is not
>> required. Therefore, use the legacy TSN Tx mode, which performs strict
>> priority arbitration.
>
> You could reflow this paragraph. The second line breaks too early.

Indeed, it does.

>
>> Example for mqprio with hardware offload:
>> 
>> |tc qdisc replace dev ${INTERFACE} handle 100 parent root mqprio num_tc 4 \
>> |   map 0 0 0 0 0 1 2 3 0 0 0 0 0 0 0 0 \
>> |   queues 1@0 1@1 1@2 1@3 \
>> |   hw 1
>
> Thank you for the example. How can you check that it actually works? No 
> errors are shown?

When using tc for setting up Qdisc(s) the command just returns without
any messages. In case there's an error the user will see messages
configured below with `extack`.

>
> Also, could you please mention the datasheet name, revision and section, 
> and on what exact device you tested this?

Sure.

>
>> Signed-off-by: Kurt Kanzenbach <[email protected]>
>> ---
>>   drivers/net/ethernet/intel/igc/igc.h         | 10 +++-
>>   drivers/net/ethernet/intel/igc/igc_defines.h |  9 ++++
>>   drivers/net/ethernet/intel/igc/igc_main.c    | 69 
>> +++++++++++++++++++++++++++
>>   drivers/net/ethernet/intel/igc/igc_regs.h    |  2 +
>>   drivers/net/ethernet/intel/igc/igc_tsn.c     | 71 
>> +++++++++++++++++++++++++++-
>>   5 files changed, 157 insertions(+), 4 deletions(-)
>> 
>> diff --git a/drivers/net/ethernet/intel/igc/igc.h 
>> b/drivers/net/ethernet/intel/igc/igc.h
>> index 45430e246e9c..c95919f085eb 100644
>> --- a/drivers/net/ethernet/intel/igc/igc.h
>> +++ b/drivers/net/ethernet/intel/igc/igc.h
>> @@ -227,6 +227,10 @@ struct igc_adapter {
>>       */
>>      spinlock_t qbv_tx_lock;
>>   
>> +    bool strict_priority_enable;
>> +    u8 num_tc;
>> +    u16 queue_per_tc[IGC_MAX_TX_QUEUES];
>> +
>>      /* OS defined structs */
>>      struct pci_dev *pdev;
>>      /* lock for statistics */
>> @@ -343,9 +347,11 @@ extern char igc_driver_name[];
>>   #define IGC_FLAG_RX_LEGACY         BIT(16)
>>   #define IGC_FLAG_TSN_QBV_ENABLED   BIT(17)
>>   #define IGC_FLAG_TSN_QAV_ENABLED   BIT(18)
>> +#define IGC_FLAG_TSN_LEGACY_ENABLED BIT(19)
>>   
>> -#define IGC_FLAG_TSN_ANY_ENABLED \
>> -    (IGC_FLAG_TSN_QBV_ENABLED | IGC_FLAG_TSN_QAV_ENABLED)
>> +#define IGC_FLAG_TSN_ANY_ENABLED                            \
>> +    (IGC_FLAG_TSN_QBV_ENABLED | IGC_FLAG_TSN_QAV_ENABLED |  \
>> +     IGC_FLAG_TSN_LEGACY_ENABLED)
>>   
>>   #define IGC_FLAG_RSS_FIELD_IPV4_UDP        BIT(6)
>>   #define IGC_FLAG_RSS_FIELD_IPV6_UDP        BIT(7)
>> diff --git a/drivers/net/ethernet/intel/igc/igc_defines.h 
>> b/drivers/net/ethernet/intel/igc/igc_defines.h
>> index 5f92b3c7c3d4..73502a0b4df7 100644
>> --- a/drivers/net/ethernet/intel/igc/igc_defines.h
>> +++ b/drivers/net/ethernet/intel/igc/igc_defines.h
>> @@ -547,6 +547,15 @@
>>   
>>   #define IGC_MAX_SR_QUEUES          2
>>   
>> +#define IGC_TXARB_TXQ_PRIO_0_SHIFT  0
>> +#define IGC_TXARB_TXQ_PRIO_1_SHIFT  2
>> +#define IGC_TXARB_TXQ_PRIO_2_SHIFT  4
>> +#define IGC_TXARB_TXQ_PRIO_3_SHIFT  6
>> +#define IGC_TXARB_TXQ_PRIO_0_MASK   GENMASK(1, 0)
>> +#define IGC_TXARB_TXQ_PRIO_1_MASK   GENMASK(3, 2)
>> +#define IGC_TXARB_TXQ_PRIO_2_MASK   GENMASK(5, 4)
>> +#define IGC_TXARB_TXQ_PRIO_3_MASK   GENMASK(7, 6)
>> +
>>   /* Receive Checksum Control */
>>   #define IGC_RXCSUM_CRCOFL  0x00000800   /* CRC32 offload enable */
>>   #define IGC_RXCSUM_PCSD            0x00002000   /* packet checksum 
>> disabled */
>> diff --git a/drivers/net/ethernet/intel/igc/igc_main.c 
>> b/drivers/net/ethernet/intel/igc/igc_main.c
>> index ba8d3fe186ae..c5d3cc3c4fa9 100644
>> --- a/drivers/net/ethernet/intel/igc/igc_main.c
>> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
>> @@ -6424,6 +6424,13 @@ static int igc_tc_query_caps(struct igc_adapter 
>> *adapter,
>>      struct igc_hw *hw = &adapter->hw;
>>   
>>      switch (base->type) {
>> +    case TC_SETUP_QDISC_MQPRIO: {
>> +            struct tc_mqprio_caps *caps = base->caps;
>> +
>> +            caps->validate_queue_counts = true;
>> +
>> +            return 0;
>> +    }
>>      case TC_SETUP_QDISC_TAPRIO: {
>>              struct tc_taprio_caps *caps = base->caps;
>>   
>> @@ -6441,6 +6448,65 @@ static int igc_tc_query_caps(struct igc_adapter 
>> *adapter,
>>      }
>>   }
>>   
>> +static void igc_save_mqprio_params(struct igc_adapter *adapter, u8 num_tc,
>> +                               u16 *offset)
>> +{
>> +    int i;
>> +
>> +    adapter->strict_priority_enable = true;
>> +    adapter->num_tc = num_tc;
>> +
>> +    for (i = 0; i < num_tc; i++)
>> +            adapter->queue_per_tc[i] = offset[i];
>> +}
>> +
>> +static int igc_tsn_enable_mqprio(struct igc_adapter *adapter,
>> +                             struct tc_mqprio_qopt_offload *mqprio)
>> +{
>> +    struct igc_hw *hw = &adapter->hw;
>> +    int i;
>> +
>> +    if (hw->mac.type != igc_i225)
>> +            return -EOPNOTSUPP;
>> +
>> +    if (!mqprio->qopt.num_tc) {
>> +            adapter->strict_priority_enable = false;
>> +            goto apply;
>> +    }
>> +
>> +    /* There are as many TCs as Tx queues. */
>> +    if (mqprio->qopt.num_tc != adapter->num_tx_queues) {
>> +            NL_SET_ERR_MSG_FMT_MOD(mqprio->extack,
>> +                                   "Only %d traffic classes supported",
>> +                                   adapter->num_tx_queues);
>
> I’d also log `mqprio->qopt.num_tc`.

num_tc is provided by the user.

>
>> +            return -EOPNOTSUPP;
>> +    }
>> +
>> +    /* Only one queue per TC is supported. */
>> +    for (i = 0; i < mqprio->qopt.num_tc; i++) {
>> +            if (mqprio->qopt.count[i] != 1) {
>> +                    NL_SET_ERR_MSG_MOD(mqprio->extack,
>> +                                       "Only one queue per TC supported");
>
> I’d also log the i and the count value.

Oki.

>
>> +                    return -EOPNOTSUPP;
>> +            }
>> +    }
>> +
>> +    /* Preemption is not supported yet. */
>> +    if (mqprio->preemptible_tcs) {
>> +            NL_SET_ERR_MSG_MOD(mqprio->extack,
>> +                               "Preemption is not supported yet");
>> +            return -EOPNOTSUPP;
>> +    }
>
> Please mention this in the commit message, maybe also included, if a 
> patch is coming soon, or what would need to be done to implement it.

Oki. At some point i'd like to see FPE implemented for igc :-).

Thanks,
Kurt

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