ice: configure GLINT_ITR to always have an ITR gran of 2

Instead of hoping that our ITR granularity will be 2 usec program the
GLINT_CTL register to make sure the ITR granularity is always 2 usecs.

Now that we know what the ITR granularity will be get rid of the check
in ice_probe() to verify our previous assumption.

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>

4 files changed, 44 insertions, 18 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_hw_autogen.h b/drivers/net/ethernet/intel/ice/ice_hw_autogen.h
index 6bf5cc064270..24255ff64ab0 100644
--- a/drivers/net/ethernet/intel/ice/ice_hw_autogen.h
+++ b/drivers/net/ethernet/intel/ice/ice_hw_autogen.h
@@ -106,6 +106,16 @@
 #define VPGEN_VFRTRIG_VFSWR_M			BIT(0)
 #define PFHMC_ERRORDATA				0x00520500
 #define PFHMC_ERRORINFO				0x00520400
+#define GLINT_CTL				0x0016CC54
+#define GLINT_CTL_DIS_AUTOMASK_M		BIT(0)
+#define GLINT_CTL_ITR_GRAN_200_S		16
+#define GLINT_CTL_ITR_GRAN_200_M		ICE_M(0xF, 16)
+#define GLINT_CTL_ITR_GRAN_100_S		20
+#define GLINT_CTL_ITR_GRAN_100_M		ICE_M(0xF, 20)
+#define GLINT_CTL_ITR_GRAN_50_S			24
+#define GLINT_CTL_ITR_GRAN_50_M			ICE_M(0xF, 24)
+#define GLINT_CTL_ITR_GRAN_25_S			28
+#define GLINT_CTL_ITR_GRAN_25_M			ICE_M(0xF, 28)
 #define GLINT_DYN_CTL(_INT)			(0x00160000 + ((_INT) * 4))
 #define GLINT_DYN_CTL_INTENA_M			BIT(0)
 #define GLINT_DYN_CTL_CLEARPBA_M		BIT(1)
diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index 5215180d08a3..c6572f6fb488 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -1714,6 +1714,37 @@ static u32 ice_intrl_usec_to_reg(u8 intrl, u8 gran)
 }
 
 /**
+ * ice_cfg_itr_gran - set the ITR granularity to 2 usecs if not already set
+ * @hw: board specific structure
+ */
+static void ice_cfg_itr_gran(struct ice_hw *hw)
+{
+	u32 regval = rd32(hw, GLINT_CTL);
+
+	/* no need to update global register if ITR gran is already set */
+	if (!(regval & GLINT_CTL_DIS_AUTOMASK_M) &&
+	    (((regval & GLINT_CTL_ITR_GRAN_200_M) >>
+	     GLINT_CTL_ITR_GRAN_200_S) == ICE_ITR_GRAN_US) &&
+	    (((regval & GLINT_CTL_ITR_GRAN_100_M) >>
+	     GLINT_CTL_ITR_GRAN_100_S) == ICE_ITR_GRAN_US) &&
+	    (((regval & GLINT_CTL_ITR_GRAN_50_M) >>
+	     GLINT_CTL_ITR_GRAN_50_S) == ICE_ITR_GRAN_US) &&
+	    (((regval & GLINT_CTL_ITR_GRAN_25_M) >>
+	      GLINT_CTL_ITR_GRAN_25_S) == ICE_ITR_GRAN_US))
+		return;
+
+	regval = ((ICE_ITR_GRAN_US << GLINT_CTL_ITR_GRAN_200_S) &
+		  GLINT_CTL_ITR_GRAN_200_M) |
+		 ((ICE_ITR_GRAN_US << GLINT_CTL_ITR_GRAN_100_S) &
+		  GLINT_CTL_ITR_GRAN_100_M) |
+		 ((ICE_ITR_GRAN_US << GLINT_CTL_ITR_GRAN_50_S) &
+		  GLINT_CTL_ITR_GRAN_50_M) |
+		 ((ICE_ITR_GRAN_US << GLINT_CTL_ITR_GRAN_25_S) &
+		  GLINT_CTL_ITR_GRAN_25_M);
+	wr32(hw, GLINT_CTL, regval);
+}
+
+/**
  * ice_cfg_itr - configure the initial interrupt throttle values
  * @hw: pointer to the HW structure
  * @q_vector: interrupt vector that's being configured
@@ -1725,6 +1756,8 @@ static u32 ice_intrl_usec_to_reg(u8 intrl, u8 gran)
 static void
 ice_cfg_itr(struct ice_hw *hw, struct ice_q_vector *q_vector, u16 vector)
 {
+	ice_cfg_itr_gran(hw);
+
 	if (q_vector->num_ring_rx) {
 		struct ice_ring_container *rc = &q_vector->rx;
 
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index 8b4c64ef85ed..4dadf8edfd84 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -2033,23 +2033,6 @@ static int ice_init_interrupt_scheme(struct ice_pf *pf)
 }
 
 /**
- * ice_verify_itr_gran - verify driver's assumption of ITR granularity
- * @pf: pointer to the PF structure
- *
- * There is no error returned here because the driver will be able to handle a
- * different ITR granularity, but interrupt moderation will not be accurate if
- * the driver's assumptions are not verified. This assumption is made so we can
- * use constants in the hot path instead of accessing structure members.
- */
-static void ice_verify_itr_gran(struct ice_pf *pf)
-{
-	if (pf->hw.itr_gran != (ICE_ITR_GRAN_S << 1))
-		dev_warn(&pf->pdev->dev,
-			 "%d ITR granularity assumption is invalid, actual ITR granularity is %d. Interrupt moderation will be inaccurate!\n",
-			 (ICE_ITR_GRAN_S << 1), pf->hw.itr_gran);
-}
-
-/**
  * ice_verify_cacheline_size - verify driver's assumption of 64 Byte cache lines
  * @pf: pointer to the PF structure
  *
@@ -2212,7 +2195,6 @@ static int ice_probe(struct pci_dev *pdev,
 	mod_timer(&pf->serv_tmr, round_jiffies(jiffies + pf->serv_tmr_period));
 
 	ice_verify_cacheline_size(pf);
-	ice_verify_itr_gran(pf);
 
 	return 0;
 
diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.h b/drivers/net/ethernet/intel/ice/ice_txrx.h
index fc358ea81816..b7ff0ff82517 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx.h
+++ b/drivers/net/ethernet/intel/ice/ice_txrx.h
@@ -125,6 +125,7 @@ enum ice_rx_dtype {
 #define ITR_IS_DYNAMIC(setting) (!!((setting) & ICE_ITR_DYNAMIC))
 #define ITR_TO_REG(setting)	((setting) & ~ICE_ITR_DYNAMIC)
 #define ICE_ITR_GRAN_S		1	/* Assume ITR granularity is 2us */
+#define ICE_ITR_GRAN_US		BIT(ICE_ITR_GRAN_S)
 #define ICE_ITR_MASK		0x1FFE	/* ITR register value alignment mask */
 #define ITR_REG_ALIGN(setting)	__ALIGN_MASK(setting, ~ICE_ITR_MASK)