i40e/i40evf: Use usec value instead of reg value for ITR defines

Instead of using the register value for the defines when setting up the
ring ITR we can just use the actual values and avoid the use of shifts and
macros to translate between the values we have and the values we want.

This helps to make the code more readable as we can quickly translate from
one value to the other.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index ac1fa9e3c04f..ade3e17fba6c 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -2277,7 +2277,7 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
 	return failure ? budget : (int)total_rx_packets;
 }
 
-static u32 i40e_buildreg_itr(const int type, const u16 itr)
+static inline u32 i40e_buildreg_itr(const int type, u16 itr)
 {
 	u32 val;
 
@@ -2290,10 +2290,17 @@ static u32 i40e_buildreg_itr(const int type, const u16 itr)
 	 * xxINT_DYN_CTLx CSR with INTENA_MSK (bit 31) set to 0 will clear
 	 * an event in the PBA anyway so we need to rely on the automask
 	 * to hold pending events for us until the interrupt is re-enabled
+	 *
+	 * The itr value is reported in microseconds, and the register
+	 * value is recorded in 2 microsecond units. For this reason we
+	 * only need to shift by the interval shift - 1 instead of the
+	 * full value.
 	 */
+	itr &= I40E_ITR_MASK;
+
 	val = I40E_PFINT_DYN_CTLN_INTENA_MASK |
 	      (type << I40E_PFINT_DYN_CTLN_ITR_INDX_SHIFT) |
-	      (itr << I40E_PFINT_DYN_CTLN_INTERVAL_SHIFT);
+	      (itr << (I40E_PFINT_DYN_CTLN_INTERVAL_SHIFT - 1));
 
 	return val;
 }