> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-boun...@osuosl.org> On Behalf Of
> Kurt Kanzenbach
> Sent: Monday, February 24, 2025 11:05 AM
> To: Nguyen, Anthony L <anthony.l.ngu...@intel.com>; Kitszel, Przemyslaw
> <przemyslaw.kits...@intel.com>; Faizal Rahim
> <faizal.abdul.ra...@linux.intel.com>
> Cc: Andrew Lunn <andrew+net...@lunn.ch>; David S. Miller
> <da...@davemloft.net>; Eric Dumazet <eduma...@google.com>; Jakub
> Kicinski <k...@kernel.org>; Paolo Abeni <pab...@redhat.com>; Sebastian
> Andrzej Siewior <bige...@linutronix.de>; intel-wired-...@lists.osuosl.org;
> net...@vger.kernel.org; Kurt Kanzenbach <k...@linutronix.de>
> Subject: [Intel-wired-lan] [PATCH iwl-next v2] igc: Change Tx mode for
> MQPRIO offloading
>
> The current MQPRIO offload implementation uses the legacy TSN Tx mode. In
> this mode the hardware uses four packet buffers and considers queue
> priorities.
>
> In order to harmonize the TAPRIO implementation with MQPRIO, switch to
> the regular TSN Tx mode. In addition to the legacy mode, transmission is
> always coupled to Qbv. The driver already has mechanisms to use a dummy
> schedule of 1 second with all gates open for ETF. Simply use this for MQPRIO
> too.
>
> This reduces code and makes it easier to add support for frame preemption
> later.
>
> While at it limit the netdev_tc calls to MQPRIO only.
>
> Tested on i225 with real time application using high priority queue, iperf3
> using low priority queue and network TAP device.
>
> Signed-off-by: Kurt Kanzenbach <k...@linutronix.de>
> ---
> Changes in v2:
> - Add comma to commit message (Faizal)
> - Simplify if condition (Faizal)
> - Link to v1: https://lore.kernel.org/r/20250217-igc_mqprio_tx_mode-v1-1-
> 3a402fe1f...@linutronix.de
> ---
> drivers/net/ethernet/intel/igc/igc.h | 4 +---
> drivers/net/ethernet/intel/igc/igc_main.c | 18 +++++++++++++-
> drivers/net/ethernet/intel/igc/igc_tsn.c | 40 ++-----------------------------
> 3 files changed, 20 insertions(+), 42 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/igc/igc.h
> b/drivers/net/ethernet/intel/igc/igc.h
> index
> cd1d7b6c1782352094f6867a31b6958c929bbbf4..16d85bdf55a7e9c412c4
> 7acf727bca6bc7154c61 100644
> --- a/drivers/net/ethernet/intel/igc/igc.h
> +++ b/drivers/net/ethernet/intel/igc/igc.h
> @@ -388,11 +388,9 @@ 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 |
> \
> - IGC_FLAG_TSN_LEGACY_ENABLED)
> + (IGC_FLAG_TSN_QBV_ENABLED | IGC_FLAG_TSN_QAV_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_main.c
> b/drivers/net/ethernet/intel/igc/igc_main.c
> index
> 3044392e8ded8619434040b9ccaa6b1babdbf685..0f44b0a6c166ae8aa798
> 93ea87f706be5d94397c 100644
> --- a/drivers/net/ethernet/intel/igc/igc_main.c
> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
> @@ -6678,13 +6678,14 @@ static int igc_tsn_enable_mqprio(struct
> igc_adapter *adapter,
> struct tc_mqprio_qopt_offload *mqprio) {
> struct igc_hw *hw = &adapter->hw;
> - int i;
> + int err, i;
>
> if (hw->mac.type != igc_i225)
> return -EOPNOTSUPP;
>
> if (!mqprio->qopt.num_tc) {
> adapter->strict_priority_enable = false;
> + netdev_reset_tc(adapter->netdev);
> goto apply;
> }
>
> @@ -6715,6 +6716,21 @@ static int igc_tsn_enable_mqprio(struct
> igc_adapter *adapter,
> igc_save_mqprio_params(adapter, mqprio->qopt.num_tc,
> mqprio->qopt.offset);
>
> + err = netdev_set_num_tc(adapter->netdev, adapter->num_tc);
> + if (err)
> + return err;
> +
> + for (i = 0; i < adapter->num_tc; i++) {
> + err = netdev_set_tc_queue(adapter->netdev, i, 1,
> + adapter->queue_per_tc[i]);
> + if (err)
> + return err;
> + }
> +
> + /* In case the card is configured with less than four queues. */
> + for (; i < IGC_MAX_TX_QUEUES; i++)
> + adapter->queue_per_tc[i] = i;
> +
> mqprio->qopt.hw = TC_MQPRIO_HW_OFFLOAD_TCS;
>
> apply:
> diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c
> b/drivers/net/ethernet/intel/igc/igc_tsn.c
> index
> 1e44374ca1ffbb86e9893266c590f318984ef574..7c28f3e7bb576f0e6a21c8
> 83e934ede4d53096f4 100644
> --- a/drivers/net/ethernet/intel/igc/igc_tsn.c
> +++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
> @@ -37,18 +37,13 @@ static unsigned int igc_tsn_new_flags(struct
> igc_adapter *adapter) {
> unsigned int new_flags = adapter->flags &
> ~IGC_FLAG_TSN_ANY_ENABLED;
>
> - if (adapter->taprio_offload_enable)
> - new_flags |= IGC_FLAG_TSN_QBV_ENABLED;
> -
> - if (is_any_launchtime(adapter))
> + if (adapter->taprio_offload_enable || is_any_launchtime(adapter) ||
> + adapter->strict_priority_enable)
Isn't sequence of:
if (adapter->taprio_offload_enable || adapter->strict_priority_enable ||
is_any_launchtime(adapter))
faster statistically?
> new_flags |= IGC_FLAG_TSN_QBV_ENABLED;
>
> if (is_cbs_enabled(adapter))
> new_flags |= IGC_FLAG_TSN_QAV_ENABLED;
>
> - if (adapter->strict_priority_enable)
> - new_flags |= IGC_FLAG_TSN_LEGACY_ENABLED;
> -
> return new_flags;
> }
>
> @@ -157,16 +152,12 @@ static int igc_tsn_disable_offload(struct
> igc_adapter *adapter)
> wr32(IGC_QBVCYCLET_S, 0);
> wr32(IGC_QBVCYCLET, NSEC_PER_SEC);
>
> - /* Reset mqprio TC configuration. */
> - netdev_reset_tc(adapter->netdev);
> -
> /* Restore the default Tx arbitration: Priority 0 has the highest
> * priority and is assigned to queue 0 and so on and so forth.
> */
> igc_tsn_tx_arb(adapter, queue_per_tc);
>
> adapter->flags &= ~IGC_FLAG_TSN_QBV_ENABLED;
> - adapter->flags &= ~IGC_FLAG_TSN_LEGACY_ENABLED;
>
> return 0;
> }
> @@ -206,37 +197,10 @@ static int igc_tsn_enable_offload(struct igc_adapter
> *adapter)
> igc_tsn_set_retx_qbvfullthreshold(adapter);
>
> if (adapter->strict_priority_enable) {
> - int err;
> -
> - err = netdev_set_num_tc(adapter->netdev, adapter-
> >num_tc);
> - if (err)
> - return err;
> -
> - for (i = 0; i < adapter->num_tc; i++) {
> - err = netdev_set_tc_queue(adapter->netdev, i, 1,
> - adapter->queue_per_tc[i]);
> - if (err)
> - return err;
> - }
> -
> - /* In case the card is configured with less than four queues. */
> - for (; i < IGC_MAX_TX_QUEUES; i++)
> - adapter->queue_per_tc[i] = i;
> -
> /* Configure queue priorities according to the user provided
> * mapping.
> */
> igc_tsn_tx_arb(adapter, adapter->queue_per_tc);
> -
> - /* Enable legacy TSN mode which will do strict priority without
> - * any other TSN features.
> - */
> - tqavctrl = rd32(IGC_TQAVCTRL);
> - tqavctrl |= IGC_TQAVCTRL_TRANSMIT_MODE_TSN;
> - tqavctrl &= ~IGC_TQAVCTRL_ENHANCED_QAV;
> - wr32(IGC_TQAVCTRL, tqavctrl);
> -
> - return 0;
> }
>
> for (i = 0; i < adapter->num_tx_queues; i++) {
>
> ---
> base-commit: b66e19dcf684b21b6d3a1844807bd1df97ad197a
> change-id: 20250214-igc_mqprio_tx_mode-22c19c564605
>
> Best regards,
> --
> Kurt Kanzenbach
> Linutronix GmbH | Bahnhofstraße 3 | D-88690 Uhldingen-Mühlhofen
> Phone: +49 7556 25 999 27; Fax.: +49 7556 25 999 99
>
> Hinweise zum Datenschutz finden Sie hier (Informations on data privacy can
> be found here): https://linutronix.de/legal/data-protection.php
>
> Linutronix GmbH | Firmensitz (Registered Office): Uhldingen-Mühlhofen |
> Registergericht (Registration Court): Amtsgericht Freiburg i.Br., HRB700
> 806 | Geschäftsführer (Managing Directors): Heinz Egger, Thomas Gleixner
> Tiffany Silva, Sean Fennelly, Jeffrey Schneiderman
