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igc: Lift TAPRIO schedule restriction
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Add support for Qbv schedules where one queue stays open
in consecutive entries. Currently that's not supported.

Example schedule:

|tc qdisc replace dev ${INTERFACE} handle 100 parent root taprio num_tc 3 \
|   map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 \
|   queues 1@0 1@1 2@2 \
|   base-time ${BASETIME} \
|   sched-entry S 0x01 300000 \ # Stream High/Low
|   sched-entry S 0x06 500000 \ # Management and Best Effort
|   sched-entry S 0x04 200000 \ # Best Effort
|   flags 0x02

Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Reviewed-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
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shifty91 authored and anguy11 committed Jul 18, 2022
1 parent 6e693a1 commit a5fd394
Showing 1 changed file with 17 additions and 6 deletions.
23 changes: 17 additions & 6 deletions drivers/net/ethernet/intel/igc/igc_main.c
Original file line number Diff line number Diff line change
Expand Up @@ -5813,9 +5813,10 @@ static bool validate_schedule(struct igc_adapter *adapter,
return false;

for (n = 0; n < qopt->num_entries; n++) {
const struct tc_taprio_sched_entry *e;
const struct tc_taprio_sched_entry *e, *prev;
int i;

prev = n ? &qopt->entries[n - 1] : NULL;
e = &qopt->entries[n];

/* i225 only supports "global" frame preemption
Expand All @@ -5828,7 +5829,12 @@ static bool validate_schedule(struct igc_adapter *adapter,
if (e->gate_mask & BIT(i))
queue_uses[i]++;

if (queue_uses[i] > 1)
/* There are limitations: A single queue cannot be
* opened and closed multiple times per cycle unless the
* gate stays open. Check for it.
*/
if (queue_uses[i] > 1 &&
!(prev->gate_mask & BIT(i)))
return false;
}
}
Expand Down Expand Up @@ -5872,6 +5878,7 @@ static int igc_tsn_clear_schedule(struct igc_adapter *adapter)
static int igc_save_qbv_schedule(struct igc_adapter *adapter,
struct tc_taprio_qopt_offload *qopt)
{
bool queue_configured[IGC_MAX_TX_QUEUES] = { };
u32 start_time = 0, end_time = 0;
size_t n;

Expand All @@ -5887,9 +5894,6 @@ static int igc_save_qbv_schedule(struct igc_adapter *adapter,
adapter->cycle_time = qopt->cycle_time;
adapter->base_time = qopt->base_time;

/* FIXME: be a little smarter about cases when the gate for a
* queue stays open for more than one entry.
*/
for (n = 0; n < qopt->num_entries; n++) {
struct tc_taprio_sched_entry *e = &qopt->entries[n];
int i;
Expand All @@ -5902,8 +5906,15 @@ static int igc_save_qbv_schedule(struct igc_adapter *adapter,
if (!(e->gate_mask & BIT(i)))
continue;

ring->start_time = start_time;
/* Check whether a queue stays open for more than one
* entry. If so, keep the start and advance the end
* time.
*/
if (!queue_configured[i])
ring->start_time = start_time;
ring->end_time = end_time;

queue_configured[i] = true;
}

start_time += e->interval;
Expand Down

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