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>

drivers/net/ethernet/intel/i40e/i40e_ethtool.c

@@ -2315,8 +2315,8 @@ static void i40e_set_itr_per_queue(struct i40e_vsi *vsi,
 
 	intrl = i40e_intrl_usec_to_reg(vsi->int_rate_limit);
 
-	rx_ring->itr_setting = ec->rx_coalesce_usecs;
-	tx_ring->itr_setting = ec->tx_coalesce_usecs;
+	rx_ring->itr_setting = ITR_REG_ALIGN(ec->rx_coalesce_usecs);
+	tx_ring->itr_setting = ITR_REG_ALIGN(ec->tx_coalesce_usecs);
 
 	if (ec->use_adaptive_rx_coalesce)
 		rx_ring->itr_setting |= I40E_ITR_DYNAMIC;
@@ -2396,7 +2396,7 @@ static int __i40e_set_coalesce(struct net_device *netdev,
 		return -EINVAL;
 	}
 
-	if (ec->rx_coalesce_usecs > (I40E_MAX_ITR << 1)) {
+	if (ec->rx_coalesce_usecs > I40E_MAX_ITR) {
 		netif_info(pf, drv, netdev, "Invalid value, rx-usecs range is 0-8160\n");
 		return -EINVAL;
 	}
@@ -2407,16 +2407,16 @@ static int __i40e_set_coalesce(struct net_device *netdev,
 		return -EINVAL;
 	}
 
-	if (ec->tx_coalesce_usecs > (I40E_MAX_ITR << 1)) {
+	if (ec->tx_coalesce_usecs > I40E_MAX_ITR) {
 		netif_info(pf, drv, netdev, "Invalid value, tx-usecs range is 0-8160\n");
 		return -EINVAL;
 	}
 
 	if (ec->use_adaptive_rx_coalesce && !cur_rx_itr)
-		ec->rx_coalesce_usecs = I40E_MIN_ITR << 1;
+		ec->rx_coalesce_usecs = I40E_MIN_ITR;
 
 	if (ec->use_adaptive_tx_coalesce && !cur_tx_itr)
-		ec->tx_coalesce_usecs = I40E_MIN_ITR << 1;
+		ec->tx_coalesce_usecs = I40E_MIN_ITR;
 
 	intrl_reg = i40e_intrl_usec_to_reg(ec->rx_coalesce_usecs_high);
 	vsi->int_rate_limit = INTRL_REG_TO_USEC(intrl_reg);

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;
 }

drivers/net/ethernet/intel/i40e/i40e_txrx.h

@@ -30,32 +30,37 @@
 #include <net/xdp.h>
 
 /* Interrupt Throttling and Rate Limiting Goodies */
-
-#define I40E_MAX_ITR               0x0FF0  /* reg uses 2 usec resolution */
-#define I40E_MIN_ITR               0x0001  /* reg uses 2 usec resolution */
-#define I40E_ITR_100K              0x0005
-#define I40E_ITR_50K               0x000A
-#define I40E_ITR_20K               0x0019
-#define I40E_ITR_18K               0x001B
-#define I40E_ITR_8K                0x003E
-#define I40E_ITR_4K                0x007A
-#define I40E_MAX_INTRL             0x3B    /* reg uses 4 usec resolution */
-#define I40E_ITR_RX_DEF            (ITR_REG_TO_USEC(I40E_ITR_20K) | \
-				    I40E_ITR_DYNAMIC)
-#define I40E_ITR_TX_DEF            (ITR_REG_TO_USEC(I40E_ITR_20K) | \
-				    I40E_ITR_DYNAMIC)
-#define I40E_ITR_DYNAMIC           0x8000  /* use top bit as a flag */
-#define I40E_MIN_INT_RATE          250     /* ~= 1000000 / (I40E_MAX_ITR * 2) */
-#define I40E_MAX_INT_RATE          500000  /* == 1000000 / (I40E_MIN_ITR * 2) */
 #define I40E_DEFAULT_IRQ_WORK      256
-#define ITR_TO_REG(setting) ((setting & ~I40E_ITR_DYNAMIC) >> 1)
-#define ITR_IS_DYNAMIC(setting) (!!(setting & I40E_ITR_DYNAMIC))
-#define ITR_REG_TO_USEC(itr_reg) (itr_reg << 1)
+
+/* The datasheet for the X710 and XL710 indicate that the maximum value for
+ * the ITR is 8160usec which is then called out as 0xFF0 with a 2usec
+ * resolution. 8160 is 0x1FE0 when written out in hex. So instead of storing
+ * the register value which is divided by 2 lets use the actual values and
+ * avoid an excessive amount of translation.
+ */
+#define I40E_ITR_DYNAMIC	0x8000	/* use top bit as a flag */
+#define I40E_ITR_MASK		0x1FFE	/* mask for ITR register value */
+#define I40E_MIN_ITR		     2	/* reg uses 2 usec resolution */
+#define I40E_ITR_100K		    10	/* all values below must be even */
+#define I40E_ITR_50K		    20
+#define I40E_ITR_20K		    50
+#define I40E_ITR_18K		    60
+#define I40E_ITR_8K		   122
+#define I40E_MAX_ITR		  8160	/* maximum value as per datasheet */
+#define ITR_TO_REG(setting) ((setting) & ~I40E_ITR_DYNAMIC)
+#define ITR_REG_ALIGN(setting) __ALIGN_MASK(setting, ~I40E_ITR_MASK)
+#define ITR_IS_DYNAMIC(setting) (!!((setting) & I40E_ITR_DYNAMIC))
+
+#define I40E_ITR_RX_DEF		(I40E_ITR_20K | I40E_ITR_DYNAMIC)
+#define I40E_ITR_TX_DEF		(I40E_ITR_20K | I40E_ITR_DYNAMIC)
+
 /* 0x40 is the enable bit for interrupt rate limiting, and must be set if
  * the value of the rate limit is non-zero
  */
 #define INTRL_ENA                  BIT(6)
+#define I40E_MAX_INTRL             0x3B    /* reg uses 4 usec resolution */
 #define INTRL_REG_TO_USEC(intrl) ((intrl & ~INTRL_ENA) << 2)
+
 /**
  * i40e_intrl_usec_to_reg - convert interrupt rate limit to register
  * @intrl: interrupt rate limit to convert

drivers/net/ethernet/intel/i40evf/i40e_txrx.c

@@ -1460,7 +1460,7 @@ 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;
 
@@ -1473,10 +1473,17 @@ 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_VFINT_DYN_CTLN1_INTENA_MASK |
 	      (type << I40E_VFINT_DYN_CTLN1_ITR_INDX_SHIFT) |
-	      (itr << I40E_VFINT_DYN_CTLN1_INTERVAL_SHIFT);
+	      (itr << (I40E_VFINT_DYN_CTLN1_INTERVAL_SHIFT - 1));
 
 	return val;
 }

drivers/net/ethernet/intel/i40evf/i40e_txrx.h

@@ -28,31 +28,35 @@
 #define _I40E_TXRX_H_
 
 /* Interrupt Throttling and Rate Limiting Goodies */
-
-#define I40E_MAX_ITR               0x0FF0  /* reg uses 2 usec resolution */
-#define I40E_MIN_ITR               0x0001  /* reg uses 2 usec resolution */
-#define I40E_ITR_100K              0x0005
-#define I40E_ITR_50K               0x000A
-#define I40E_ITR_20K               0x0019
-#define I40E_ITR_18K               0x001B
-#define I40E_ITR_8K                0x003E
-#define I40E_ITR_4K                0x007A
-#define I40E_MAX_INTRL             0x3B    /* reg uses 4 usec resolution */
-#define I40E_ITR_RX_DEF            (ITR_REG_TO_USEC(I40E_ITR_20K) | \
-				    I40E_ITR_DYNAMIC)
-#define I40E_ITR_TX_DEF            (ITR_REG_TO_USEC(I40E_ITR_20K) | \
-				    I40E_ITR_DYNAMIC)
-#define I40E_ITR_DYNAMIC           0x8000  /* use top bit as a flag */
-#define I40E_MIN_INT_RATE          250     /* ~= 1000000 / (I40E_MAX_ITR * 2) */
-#define I40E_MAX_INT_RATE          500000  /* == 1000000 / (I40E_MIN_ITR * 2) */
 #define I40E_DEFAULT_IRQ_WORK      256
-#define ITR_TO_REG(setting) ((setting & ~I40E_ITR_DYNAMIC) >> 1)
-#define ITR_IS_DYNAMIC(setting) (!!(setting & I40E_ITR_DYNAMIC))
-#define ITR_REG_TO_USEC(itr_reg) (itr_reg << 1)
+
+/* The datasheet for the X710 and XL710 indicate that the maximum value for
+ * the ITR is 8160usec which is then called out as 0xFF0 with a 2usec
+ * resolution. 8160 is 0x1FE0 when written out in hex. So instead of storing
+ * the register value which is divided by 2 lets use the actual values and
+ * avoid an excessive amount of translation.
+ */
+#define I40E_ITR_DYNAMIC	0x8000	/* use top bit as a flag */
+#define I40E_ITR_MASK		0x1FFE	/* mask for ITR register value */
+#define I40E_MIN_ITR		     2	/* reg uses 2 usec resolution */
+#define I40E_ITR_100K		    10	/* all values below must be even */
+#define I40E_ITR_50K		    20
+#define I40E_ITR_20K		    50
+#define I40E_ITR_18K		    60
+#define I40E_ITR_8K		   122
+#define I40E_MAX_ITR		  8160	/* maximum value as per datasheet */
+#define ITR_TO_REG(setting) ((setting) & ~I40E_ITR_DYNAMIC)
+#define ITR_REG_ALIGN(setting) __ALIGN_MASK(setting, ~I40E_ITR_MASK)
+#define ITR_IS_DYNAMIC(setting) (!!((setting) & I40E_ITR_DYNAMIC))
+
+#define I40E_ITR_RX_DEF		(I40E_ITR_20K | I40E_ITR_DYNAMIC)
+#define I40E_ITR_TX_DEF		(I40E_ITR_20K | I40E_ITR_DYNAMIC)
+
 /* 0x40 is the enable bit for interrupt rate limiting, and must be set if
  * the value of the rate limit is non-zero
  */
 #define INTRL_ENA                  BIT(6)
+#define I40E_MAX_INTRL             0x3B    /* reg uses 4 usec resolution */
 #define INTRL_REG_TO_USEC(intrl) ((intrl & ~INTRL_ENA) << 2)
 #define INTRL_USEC_TO_REG(set) ((set) ? ((set) >> 2) | INTRL_ENA : 0)
 #define I40E_INTRL_8K              125     /* 8000 ints/sec */

drivers/net/ethernet/intel/i40evf/i40evf_ethtool.c

@@ -517,8 +517,8 @@ static void i40evf_set_itr_per_queue(struct i40evf_adapter *adapter,
 	struct i40e_hw *hw = &adapter->hw;
 	struct i40e_q_vector *q_vector;
 
-	rx_ring->itr_setting = ec->rx_coalesce_usecs;
-	tx_ring->itr_setting = ec->tx_coalesce_usecs;
+	rx_ring->itr_setting = ITR_REG_ALIGN(ec->rx_coalesce_usecs);
+	tx_ring->itr_setting = ITR_REG_ALIGN(ec->tx_coalesce_usecs);
 
 	rx_ring->itr_setting |= I40E_ITR_DYNAMIC;
 	if (!ec->use_adaptive_rx_coalesce)
@@ -563,8 +563,8 @@ static int __i40evf_set_coalesce(struct net_device *netdev,
 	if (ec->rx_coalesce_usecs == 0) {
 		if (ec->use_adaptive_rx_coalesce)
 			netif_info(adapter, drv, netdev, "rx-usecs=0, need to disable adaptive-rx for a complete disable\n");
-	} else if ((ec->rx_coalesce_usecs < (I40E_MIN_ITR << 1)) ||
-		   (ec->rx_coalesce_usecs > (I40E_MAX_ITR << 1))) {
+	} else if ((ec->rx_coalesce_usecs < I40E_MIN_ITR) ||
+		   (ec->rx_coalesce_usecs > I40E_MAX_ITR)) {
 		netif_info(adapter, drv, netdev, "Invalid value, rx-usecs range is 0-8160\n");
 		return -EINVAL;
 	}
@@ -573,8 +573,8 @@ static int __i40evf_set_coalesce(struct net_device *netdev,
 	if (ec->tx_coalesce_usecs == 0) {
 		if (ec->use_adaptive_tx_coalesce)
 			netif_info(adapter, drv, netdev, "tx-usecs=0, need to disable adaptive-tx for a complete disable\n");
-	} else if ((ec->tx_coalesce_usecs < (I40E_MIN_ITR << 1)) ||
-		   (ec->tx_coalesce_usecs > (I40E_MAX_ITR << 1))) {
+	} else if ((ec->tx_coalesce_usecs < I40E_MIN_ITR) ||
+		   (ec->tx_coalesce_usecs > I40E_MAX_ITR)) {
 		netif_info(adapter, drv, netdev, "Invalid value, tx-usecs range is 0-8160\n");
 		return -EINVAL;
 	}