From 9a8648cce8d8a4a7770b45239912e20edb9736ad Mon Sep 17 00:00:00 2001 From: Jacob Keller Date: Thu, 1 Jun 2023 14:15:06 -0700 Subject: ice: trigger PFINT_OICR_TSYN_TX interrupt instead of polling In ice_misc_intr_thread_fn(), if we do not complete all Tx timestamp work, the thread function will poll continuously forever. For E822 hardware, this wastes time as the return value from ice_ptp_process_ts() is accurate and always reports correctly that the PHY actually has new timestamp data. In addition, if we receive enough timestamps with the right pacing, we may never exit this polling. Should this occur, other tasks handled by the ice_misc_intr_thread_fn() will never be processed. Fix this by instead writing to PFINT_OICR, causing an emulated interrupt to be triggered immediately. This does take slightly more processing than just re-checking the timestamps. However, it allows all of the other interrupt causes a chance to be processed first in the hard IRQ function. Note that the OICR interrupt is configured to be throttled to no more than once every 124 microseconds. This gives an effective interrupt rate of ~8000 interrupts per second. This should thus not cause a significant increase in overall CPU usage when compared to sleeping. Signed-off-by: Jacob Keller Tested-by: Arpana Arland (A Contingent worker at Intel) Signed-off-by: Tony Nguyen --- drivers/net/ethernet/intel/ice/ice_main.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'drivers/net/ethernet') diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c index 6811e2a3c154..2665f72b5461 100644 --- a/drivers/net/ethernet/intel/ice/ice_main.c +++ b/drivers/net/ethernet/intel/ice/ice_main.c @@ -3202,8 +3202,15 @@ static irqreturn_t ice_misc_intr_thread_fn(int __always_unused irq, void *data) ice_ptp_extts_event(pf); if (test_and_clear_bit(ICE_MISC_THREAD_TX_TSTAMP, pf->misc_thread)) { - while (ice_ptp_process_ts(pf) == ICE_TX_TSTAMP_WORK_PENDING) - usleep_range(50, 100); + struct ice_hw *hw = &pf->hw; + + /* Process outstanding Tx timestamps. If there is more work, + * re-arm the interrupt to trigger again. + */ + if (ice_ptp_process_ts(pf) == ICE_TX_TSTAMP_WORK_PENDING) { + wr32(hw, PFINT_OICR, PFINT_OICR_TSYN_TX_M); + ice_flush(hw); + } } return IRQ_HANDLED; -- cgit v1.2.3