[Intel-wired-lan] [PATCH S22 04/16] ice: Always set prefena when configuring an Rx queue

[Tony Nguyen]

From: Brett Creeley <brett.creeley at intel.com>

Currently we are always setting prefena to 0. This is causing the
hardware to only fetch descriptors when there are none free in the cache
for a received packet instead of prefetching when it has used the last
descriptor regardless of incoming packets. Fix this by allowing the
hardware to prefetch Rx descriptors.

Signed-off-by: Brett Creeley <brett.creeley at intel.com>
---
 drivers/net/ethernet/intel/ice/ice_common.c    | 9 ++++++++-
 drivers/net/ethernet/intel/ice/ice_lan_tx_rx.h | 1 +
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_common.c b/drivers/net/ethernet/intel/ice/ice_common.c
index 4be3559de207..01e5ecaaa322 100644
--- a/drivers/net/ethernet/intel/ice/ice_common.c
+++ b/drivers/net/ethernet/intel/ice/ice_common.c
@@ -1078,6 +1078,7 @@ static const struct ice_ctx_ele ice_rlan_ctx_info[] = {
 	ICE_CTX_STORE(ice_rlan_ctx, tphdata_ena,	1,	195),
 	ICE_CTX_STORE(ice_rlan_ctx, tphhead_ena,	1,	196),
 	ICE_CTX_STORE(ice_rlan_ctx, lrxqthresh,		3,	198),
+	ICE_CTX_STORE(ice_rlan_ctx, prefena,		1,	201),
 	{ 0 }
 };
 
@@ -1088,7 +1089,8 @@ static const struct ice_ctx_ele ice_rlan_ctx_info[] = {
  * @rxq_index: the index of the Rx queue
  *
  * Converts rxq context from sparse to dense structure and then writes
- * it to HW register space
+ * it to HW register space and enables the hardware to prefetch descriptors
+ * instead of only fetching them on demand
  */
 enum ice_status
 ice_write_rxq_ctx(struct ice_hw *hw, struct ice_rlan_ctx *rlan_ctx,
@@ -1096,6 +1098,11 @@ ice_write_rxq_ctx(struct ice_hw *hw, struct ice_rlan_ctx *rlan_ctx,
 {
 	u8 ctx_buf[ICE_RXQ_CTX_SZ] = { 0 };
 
+	if (!rlan_ctx)
+		return ICE_ERR_BAD_PTR;
+
+	rlan_ctx->prefena = 1;
+
 	ice_set_ctx((u8 *)rlan_ctx, ctx_buf, ice_rlan_ctx_info);
 	return ice_copy_rxq_ctx_to_hw(hw, ctx_buf, rxq_index);
 }
diff --git a/drivers/net/ethernet/intel/ice/ice_lan_tx_rx.h b/drivers/net/ethernet/intel/ice/ice_lan_tx_rx.h
index 510a8c900e61..57ea6811fe2c 100644
--- a/drivers/net/ethernet/intel/ice/ice_lan_tx_rx.h
+++ b/drivers/net/ethernet/intel/ice/ice_lan_tx_rx.h
@@ -290,6 +290,7 @@ struct ice_rlan_ctx {
 	u8 tphdata_ena;
 	u8 tphhead_ena;
 	u16 lrxqthresh; /* bigger than needed, see above for reason */
+	u8 prefena;	/* NOTE: normally must be set to 1 at init */
 };
 
 struct ice_ctx_ele {
-- 
2.20.1