ionic: missed doorbell workaround

In one version of the HW there is a remote possibility that it
will miss the doorbell ring.  This adds a bit of protection to
be sure we don't stall a queue from a missed doorbell.

Fixes: 0f3154e6bcb3 ("ionic: Add Tx and Rx handling")
Signed-off-by: Allen Hubbe <allen.hubbe@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_main.c b/drivers/net/ethernet/pensando/ionic/ionic_main.c
index a13530ec4dd8..08c42b039d92 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_main.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_main.c
@@ -289,6 +289,35 @@ static void ionic_adminq_cb(struct ionic_queue *q,
 	complete_all(&ctx->work);
 }
 
+bool ionic_adminq_poke_doorbell(struct ionic_queue *q)
+{
+	struct ionic_lif *lif = q->lif;
+	unsigned long now, then, dif;
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&lif->adminq_lock, irqflags);
+
+	if (q->tail_idx == q->head_idx) {
+		spin_unlock_irqrestore(&lif->adminq_lock, irqflags);
+		return false;
+	}
+
+	now = READ_ONCE(jiffies);
+	then = q->dbell_jiffies;
+	dif = now - then;
+
+	if (dif > q->dbell_deadline) {
+		ionic_dbell_ring(q->lif->kern_dbpage, q->hw_type,
+				 q->dbval | q->head_idx);
+
+		q->dbell_jiffies = now;
+	}
+
+	spin_unlock_irqrestore(&lif->adminq_lock, irqflags);
+
+	return true;
+}
+
 int ionic_adminq_post(struct ionic_lif *lif, struct ionic_admin_ctx *ctx)
 {
 	struct ionic_desc_info *desc_info;