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:
- 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.
- 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().
- i226 doesn't reset adapter for tsn->legacy tx mode changes. It only resets adapter for legacy->tsn tx mode transitions.
- 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:
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)
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@linux.intel.com
Hi Faizal,
Nits below not withstahdning, this looks good to me.
Reviewed-by: Simon Horman horms@kernel.org
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.
(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)) {-- 2.25.1