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, 4 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
index fc6bc1233f10..0b269c470343 100644
--- a/drivers/net/ethernet/intel/ice/ice.h
+++ b/drivers/net/ethernet/intel/ice/ice.h
@@ -230,6 +230,10 @@ struct ice_q_vector {
         u8 num_ring_tx;                 /* total number of tx rings in vector */
         u8 num_ring_rx;                 /* total number of rx rings in vector */
         char name[ICE_INT_NAME_STR_LEN];
+        /* in usecs, need to use ice_intrl_to_usecs_reg() before writing this
+         * value to the device
+         */
+        u8 intrl;
 } ____cacheline_internodealigned_in_smp;
 
 enum ice_pf_flags {