[PATCH 04/23] staging/rdma/hfi1: Implement time-out for send context halt recovery

[ira.weiny@xxxxxxxxx]

From: Vennila Megavannan <vennila.megavannan@xxxxxxxxx>

This patch increases the timout for packet egress to 500 us and timer
resets to zero if the packet occupancy changes. Also we bounce the link
on time out.

Reviewed-by: Dean Luick <dean.luick@xxxxxxxxx>
Signed-off-by: Vennila Megavannan <vennila.megavannan@xxxxxxxxx>
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
---
 drivers/staging/rdma/hfi1/pio.c  | 14 +++++++++++---
 drivers/staging/rdma/hfi1/sdma.c | 15 ++++++++++++---
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/rdma/hfi1/pio.c b/drivers/staging/rdma/hfi1/pio.c
index 67dd93a6888c..e5c32db4bc67 100644
--- a/drivers/staging/rdma/hfi1/pio.c
+++ b/drivers/staging/rdma/hfi1/pio.c
@@ -922,10 +922,12 @@ void sc_disable(struct send_context *sc)
 static void sc_wait_for_packet_egress(struct send_context *sc, int pause)
 {
 	struct hfi1_devdata *dd = sc->dd;
-	u64 reg;
+	u64 reg = 0;
+	u64 reg_prev;
 	u32 loop = 0;
 
 	while (1) {
+		reg_prev = reg;
 		reg = read_csr(dd, sc->hw_context * 8 +
 			       SEND_EGRESS_CTXT_STATUS);
 		/* done if egress is stopped */
@@ -934,11 +936,17 @@ static void sc_wait_for_packet_egress(struct send_context *sc, int pause)
 		reg = packet_occupancy(reg);
 		if (reg == 0)
 			break;
-		if (loop > 100) {
+		/* counter is reset if occupancy count changes */
+		if (reg != reg_prev)
+			loop = 0;
+		if (loop > 500) {
+			/* timed out - bounce the link */
 			dd_dev_err(dd,
-				"%s: context %u(%u) timeout waiting for packets to egress, remaining count %u\n",
+				"%s: context %u(%u) timeout waiting for packets to egress, remaining count %u, bouncing link\n",
 				__func__, sc->sw_index,
 				sc->hw_context, (u32)reg);
+			queue_work(dd->pport->hfi1_wq,
+				&dd->pport->link_bounce_work);
 			break;
 		}
 		loop++;
diff --git a/drivers/staging/rdma/hfi1/sdma.c b/drivers/staging/rdma/hfi1/sdma.c
index 63ab72102183..d57531796723 100644
--- a/drivers/staging/rdma/hfi1/sdma.c
+++ b/drivers/staging/rdma/hfi1/sdma.c
@@ -303,17 +303,26 @@ static void sdma_wait_for_packet_egress(struct sdma_engine *sde,
 	u64 off = 8 * sde->this_idx;
 	struct hfi1_devdata *dd = sde->dd;
 	int lcnt = 0;
+	u64 reg_prev;
+	u64 reg = 0;
 
 	while (1) {
-		u64 reg = read_csr(dd, off + SEND_EGRESS_SEND_DMA_STATUS);
+		reg_prev = reg;
+		reg = read_csr(dd, off + SEND_EGRESS_SEND_DMA_STATUS);
 
 		reg &= SDMA_EGRESS_PACKET_OCCUPANCY_SMASK;
 		reg >>= SDMA_EGRESS_PACKET_OCCUPANCY_SHIFT;
 		if (reg == 0)
 			break;
-		if (lcnt++ > 100) {
-			dd_dev_err(dd, "%s: engine %u timeout waiting for packets to egress, remaining count %u\n",
+		/* counter is reest if accupancy count changes */
+		if (reg != reg_prev)
+			lcnt = 0;
+		if (lcnt++ > 500) {
+			/* timed out - bounce the link */
+			dd_dev_err(dd, "%s: engine %u timeout waiting for packets to egress, remaining count %u, bouncing link\n",
 				  __func__, sde->this_idx, (u32)reg);
+			queue_work(dd->pport->hfi1_wq,
+				&dd->pport->link_bounce_work);
 			break;
 		}
 		udelay(1);
-- 
1.8.2

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