ice: Add support for dynamic interrupt moderation

Currently there is no support for dynamic interrupt moderation. This
patch adds some initial code to support this. The following changes
were made:

1. Currently we are using multiple members to store the interrupt
   granularity (itr_gran_25/50/100/200). This is not necessary because
   we can query the device to determine what the interrupt granularity
   should be set to, done by a new function ice_get_itr_intrl_gran.

2. Added intrl to ice_q_vector structure to support interrupt rate
   limiting.

3. Added the function ice_intrl_usecs_to_reg for converting to a value
   in usecs that the device understands.

4. Added call to write to the GLINT_RATE register. Disable intrl by
   default for now.

5. Changed rx/tx_itr_setting to itr_setting because having both seems
   redundant because a ring is either Tx or Rx.

6. Initialize itr_setting for both Tx/Rx rings in ice_vsi_alloc_rings()

Signed-off-by: Brett Creeley <brett.creeley@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 36 insertions, 5 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_common.c b/drivers/net/ethernet/intel/ice/ice_common.c
index 9ff291375869..68fbbb92d504 100644
--- a/drivers/net/ethernet/intel/ice/ice_common.c
+++ b/drivers/net/ethernet/intel/ice/ice_common.c
@@ -598,6 +598,39 @@ void ice_output_fw_log(struct ice_hw *hw, struct ice_aq_desc *desc, void *buf)
 }
 
 /**
+ * ice_get_itr_intrl_gran - determine int/intrl granularity
+ * @hw: pointer to the hw struct
+ *
+ * Determines the itr/intrl granularities based on the maximum aggregate
+ * bandwidth according to the device's configuration during power-on.
+ */
+static enum ice_status ice_get_itr_intrl_gran(struct ice_hw *hw)
+{
+        u8 max_agg_bw = (rd32(hw, GL_PWR_MODE_CTL) &
+                         GL_PWR_MODE_CTL_CAR_MAX_BW_M) >>
+                        GL_PWR_MODE_CTL_CAR_MAX_BW_S;
+
+        switch (max_agg_bw) {
+        case ICE_MAX_AGG_BW_200G:
+        case ICE_MAX_AGG_BW_100G:
+        case ICE_MAX_AGG_BW_50G:
+                hw->itr_gran = ICE_ITR_GRAN_ABOVE_25;
+                hw->intrl_gran = ICE_INTRL_GRAN_ABOVE_25;
+                break;
+        case ICE_MAX_AGG_BW_25G:
+                hw->itr_gran = ICE_ITR_GRAN_MAX_25;
+                hw->intrl_gran = ICE_INTRL_GRAN_MAX_25;
+                break;
+        default:
+                ice_debug(hw, ICE_DBG_INIT,
+                          "Failed to determine itr/intrl granularity\n");
+                return ICE_ERR_CFG;
+        }
+
+        return 0;
+}
+
+/**
  * ice_init_hw - main hardware initialization routine
  * @hw: pointer to the hardware structure
  */
@@ -621,11 +654,9 @@ enum ice_status ice_init_hw(struct ice_hw *hw)
         if (status)
                 return status;
 
-        /* set these values to minimum allowed */
-        hw->itr_gran_200 = ICE_ITR_GRAN_MIN_200;
-        hw->itr_gran_100 = ICE_ITR_GRAN_MIN_100;
-        hw->itr_gran_50 = ICE_ITR_GRAN_MIN_50;
-        hw->itr_gran_25 = ICE_ITR_GRAN_MIN_25;
+        status = ice_get_itr_intrl_gran(hw);
+        if (status)
+                return status;
 
         status = ice_init_all_ctrlq(hw);
         if (status)