[PATCH 5.15 599/731] igc: Lift TAPRIO schedule restriction

Greg Kroah-Hartman
2022-12-28T15:46:40Z

From: Kurt Kanzenbach <kurt@linutronix.de>

[ Upstream commit a5fd39464a4081ce11c801d7e20c4551ba7cb983 ]

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>
Stable-dep-of: 72abeedd8398 ("igc: Set Qbv start_time and end_time to end_time if not being configured in GCL")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/intel/igc/igc_main.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index df78aa4fb44b..791f59d09d28 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -5919,9 +5919,10 @@ 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
@@ -5934,7 +5935,12 @@ 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;
}
}
@@ -5978,6 +5984,7 @@ 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;

@@ -5998,9 +6005,6 @@ 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;
@@ -6028,8 +6032,15 @@ 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;
--
2.35.1