On Tue, Jul 02, 2024 at 12:09:24AM -0400, Faizal Rahim wrote:
> Following the "igc: Fix TX Hang issue when QBV Gate is close" changes,
> remaining issues with the reset adapter logic in igc_tsn_offload_apply()
> have been observed:
>
> 1. The reset adapter logics for i225 and i226 differ, although they should
> be the same according to the guidelines in I225/6 HW Design Section
> 7.5.2.1 on software initialization during tx mode changes.
> 2. The i225 resets adapter every time, even though tx mode doesn't change.
> This occurs solely based on the condition igc_is_device_id_i225() when
> calling schedule_work().
> 3. i226 doesn't reset adapter for tsn->legacy tx mode changes. It only
> resets adapter for legacy->tsn tx mode transitions.
> 4. qbv_count introduced in the patch is actually not needed; in this
> context, a non-zero value of qbv_count is used to indicate if tx mode
> was unconditionally set to tsn in igc_tsn_enable_offload(). This could
> be replaced by checking the existing register
> IGC_TQAVCTRL_TRANSMIT_MODE_TSN bit.
>
> This patch resolves all issues and enters schedule_work() to reset the
> adapter only when changing tx mode. It also removes reliance on qbv_count.
>
> qbv_count field will be removed in a future patch.
>
> Test ran:
>
> 1. Verify reset adapter behaviour in i225/6:
> a) Enrol a new GCL
> Reset adapter observed (tx mode change legacy->tsn)
> b) Enrol a new GCL without deleting qdisc
> No reset adapter observed (tx mode remain tsn->tsn)
> c) Delete qdisc
> Reset adapter observed (tx mode change tsn->legacy)
>
> 2. Tested scenario from "igc: Fix TX Hang issue when QBV Gate is closed"
> to confirm it remains resolved.
>
> Fixes: 175c241288c0 ("igc: Fix TX Hang issue when QBV Gate is closed")
> Signed-off-by: Faizal Rahim <faizal.abdul.rahim@xxxxxxxxxxxxxxx>
Hi Faizal,
Nits below not withstahdning, this looks good to me.
Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
> ---
> drivers/net/ethernet/intel/igc/igc_tsn.c | 26 +++++++++++++++++++++---
> 1 file changed, 23 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c
> index 02dd41aff634..61f047ebf34d 100644
> --- a/drivers/net/ethernet/intel/igc/igc_tsn.c
> +++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
> @@ -49,6 +49,13 @@ static unsigned int igc_tsn_new_flags(struct igc_adapter *adapter)
> return new_flags;
> }
>
> +static bool igc_tsn_is_tx_mode_in_tsn(struct igc_adapter *adapter)
> +{
> + struct igc_hw *hw = &adapter->hw;
> +
> + return (bool)(rd32(IGC_TQAVCTRL) & IGC_TQAVCTRL_TRANSMIT_MODE_TSN);
Perhaps it is more a question of taste than anything else.
But my preference, FIIW, is to avoid casts.
And I think in this case using !! is a common pattern.
(Completely untested!)
return !!(rd32(IGC_TQAVCTRL) & IGC_TQAVCTRL_TRANSMIT_MODE_TSN);
> +}
> +
> void igc_tsn_adjust_txtime_offset(struct igc_adapter *adapter)
> {
> struct igc_hw *hw = &adapter->hw;
> @@ -334,15 +341,28 @@ int igc_tsn_reset(struct igc_adapter *adapter)
> return err;
> }
>
> +static bool igc_tsn_will_tx_mode_change(struct igc_adapter *adapter)
> +{
> + bool any_tsn_enabled = (bool)(igc_tsn_new_flags(adapter) &
> + IGC_FLAG_TSN_ANY_ENABLED);
Ditto.
> +
> + if ((any_tsn_enabled && !igc_tsn_is_tx_mode_in_tsn(adapter)) ||
> + (!any_tsn_enabled && igc_tsn_is_tx_mode_in_tsn(adapter)))
> + return true;
> + else
> + return false;
Likewise, this is probably more a matter of taste than anything else.
But I think this could be expressed as:
(Completely untested!)
return (any_tsn_enabled && !igc_tsn_is_tx_mode_in_tsn(adapter)) ||
(!any_tsn_enabled && igc_tsn_is_tx_mode_in_tsn(adapter));
Similarly in the previous patch of this series.
> +}
> +
> int igc_tsn_offload_apply(struct igc_adapter *adapter)
> {
> struct igc_hw *hw = &adapter->hw;
>
> - /* Per I225/6 HW Design Section 7.5.2.1, transmit mode
> - * cannot be changed dynamically. Require reset the adapter.
> + /* Per I225/6 HW Design Section 7.5.2.1 guideline, if tx mode change
> + * from legacy->tsn or tsn->legacy, then reset adapter is needed.
> */
> if (netif_running(adapter->netdev) &&
> - (igc_is_device_id_i225(hw) || !adapter->qbv_count)) {
> + (igc_is_device_id_i225(hw) || igc_is_device_id_i226(hw)) &&
> + igc_tsn_will_tx_mode_change(adapter)) {
> schedule_work(&adapter->reset_task);
> return 0;
> }
> --
> 2.25.1
>
>
