ice: move prefetch enable to ice_setup_rx_ctx

The ice_write_rxq_ctx() function is responsible for programming the Rx
Queue context into hardware. It receives the configuration in unpacked form
via the ice_rlan_ctx structure.

This function unconditionally modifies the context to set the prefetch
enable bit. This was done by commit c31a5c25bb19 ("ice: Always set prefena
when configuring an Rx queue"). Setting this bit makes sense, since
prefetching descriptors is almost always the preferred behavior.

However, the ice_write_rxq_ctx() function is not the place that actually
defines the queue context. We initialize the Rx Queue context in
ice_setup_rx_ctx(). It is surprising to have the Rx queue context changed
by a function who's responsibility is to program the given context to
hardware.

Following the principle of least surprise, move the setting of the prefetch
enable bit out of ice_write_rxq_ctx() and into the ice_setup_rx_ctx().

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20241210-packing-pack-fields-and-ice-implementation-v10-9-ee56a47479ac@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/intel/ice/ice_base.c b/drivers/net/ethernet/intel/ice/ice_base.c
index 5fe7b5a100202e6f0c33c617c604d45f9487b1f4..b2af8e3586f7620d372f2055e337485d102d3cbc 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_base.c
+++ b/drivers/net/ethernet/intel/ice/ice_base.c
@@ -454,6 +454,9 @@ static int ice_setup_rx_ctx(struct ice_rx_ring *ring)
        /* Rx queue threshold in units of 64 */
        rlan_ctx.lrxqthresh = 1;
 
+       /* Enable descriptor prefetch */
+       rlan_ctx.prefena = 1;
+
        /* PF acts as uplink for switchdev; set flex descriptor with src_vsi
         * metadata and flags to allow redirecting to PR netdev
         */

diff --git a/drivers/net/ethernet/intel/ice/ice_common.c b/drivers/net/ethernet/intel/ice/ice_common.c
index 8683c9ac6cedc5a6f9b34f347784c496ec08b840..4c6cc48aaef0c31eaa1d9de35effcd812933d270 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_common.c
+++ b/drivers/net/ethernet/intel/ice/ice_common.c
@@ -1433,14 +1433,13 @@ static void ice_pack_rxq_ctx(const struct ice_rlan_ctx *ctx,
 }
 
 /**
- * ice_write_rxq_ctx
+ * ice_write_rxq_ctx - Write Rx Queue context to hardware
  * @hw: pointer to the hardware structure
  * @rlan_ctx: pointer to the rxq context
  * @rxq_index: the index of the Rx queue
  *
- * Converts rxq context from sparse to dense structure and then writes
- * it to HW register space and enables the hardware to prefetch descriptors
- * instead of only fetching them on demand
+ * Pack the sparse Rx Queue context into dense hardware format and write it
+ * into the HW register space.
  */
 int ice_write_rxq_ctx(struct ice_hw *hw, struct ice_rlan_ctx *rlan_ctx,
                      u32 rxq_index)
@@ -1450,8 +1449,6 @@ int ice_write_rxq_ctx(struct ice_hw *hw, struct ice_rlan_ctx *rlan_ctx,
        if (!rlan_ctx)
                return -EINVAL;
 
-       rlan_ctx->prefena = 1;
-
        ice_pack_rxq_ctx(rlan_ctx, &buf);
 
        return ice_copy_rxq_ctx_to_hw(hw, &buf, rxq_index);