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, 11 insertions, 6 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.h b/drivers/net/ethernet/intel/ice/ice_txrx.h
index 839fd9ff6043..a9b92974e041 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx.h
+++ b/drivers/net/ethernet/intel/ice/ice_txrx.h
@@ -104,10 +104,16 @@ enum ice_rx_dtype {
 #define ICE_RX_ITR	ICE_IDX_ITR0
 #define ICE_TX_ITR	ICE_IDX_ITR1
 #define ICE_ITR_DYNAMIC	0x8000  /* use top bit as a flag */
-#define ICE_ITR_8K	0x003E
+#define ICE_ITR_8K	125
+#define ICE_DFLT_TX_ITR	ICE_ITR_8K
+#define ICE_DFLT_RX_ITR	ICE_ITR_8K
+/* apply ITR granularity translation to program the register. itr_gran is either
+ * 2 or 4 usecs so we need to divide by 2 first then shift by that value
+ */
+#define ITR_TO_REG(val, itr_gran) (((val) & ~ICE_ITR_DYNAMIC) >> \
+				   ((itr_gran) / 2))
 
-/* apply ITR HW granularity translation to program the HW registers */
-#define ITR_TO_REG(val, itr_gran) (((val) & ~ICE_ITR_DYNAMIC) >> (itr_gran))
+#define ICE_DFLT_INTRL	0
 
 /* Legacy or Advanced Mode Queue */
 #define ICE_TX_ADVANCED	0
@@ -130,12 +136,11 @@ struct ice_ring {
 	u32 txq_teid;			/* Added Tx queue TEID */
 
 	/* high bit set means dynamic, use accessor routines to read/write.
-	 * hardware supports 2us/1us resolution for the ITR registers.
+	 * hardware supports 4us/2us resolution for the ITR registers.
 	 * these values always store the USER setting, and must be converted
 	 * before programming to a register.
 	 */
-	u16 rx_itr_setting;
-	u16 tx_itr_setting;
+	u16 itr_setting;
 
 	u16 count;			/* Number of descriptors */
 	u16 reg_idx;			/* HW register index of the ring */