net: aquantia: improve LRO configuration

Default LRO HW configuration was very conservative.

Low Number of Descriptors per LRO Sequence, small session
timeout, inefficient settings in interrupt generation logic.

Change max number of LRO descriptors from 2 to 16 to
increase performance. Increase maximum coalescing interval
in HW to 250uS. Tune up HW LRO interrupt generation setting
to prevent hw issues with long LRO sessions.
Signed-off-by: Nikita Danilov <nikita.danilov@aquantia.com>
Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c

@@ -259,7 +259,13 @@ static int hw_atl_b0_hw_offload_set(struct aq_hw_s *self,
 
 		hw_atl_rpo_lro_time_base_divider_set(self, 0x61AU);
 		hw_atl_rpo_lro_inactive_interval_set(self, 0);
-		hw_atl_rpo_lro_max_coalescing_interval_set(self, 2);
+		/* the LRO timebase divider is 5 uS (0x61a),
+		 * which is multiplied by 50(0x32)
+		 * to get a maximum coalescing interval of 250 uS,
+		 * which is the default value
+		 */
+		hw_atl_rpo_lro_max_coalescing_interval_set(self, 50);
+
 
 		hw_atl_rpo_lro_qsessions_lim_set(self, 1U);
 
@@ -273,6 +279,10 @@ static int hw_atl_b0_hw_offload_set(struct aq_hw_s *self,
 
 		hw_atl_rpo_lro_en_set(self,
 				      aq_nic_cfg->is_lro ? 0xFFFFFFFFU : 0U);
+		hw_atl_itr_rsc_en_set(self,
+				      aq_nic_cfg->is_lro ? 0xFFFFFFFFU : 0U);
+
+		hw_atl_itr_rsc_delay_set(self, 1U);
 	}
 	return aq_hw_err_from_flags(self);
 }

drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0_internal.h

@@ -78,7 +78,7 @@
 #define HW_ATL_B0_TC_MAX 1U
 #define HW_ATL_B0_RSS_MAX 8U
 
-#define HW_ATL_B0_LRO_RXD_MAX 2U
+#define HW_ATL_B0_LRO_RXD_MAX 16U
 #define HW_ATL_B0_RS_SLIP_ENABLED  0U
 
 /* (256k -1(max pay_len) - 54(header)) */

drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_llh.c

@@ -315,6 +315,21 @@ void hw_atl_itr_res_irq_set(struct aq_hw_s *aq_hw, u32 res_irq)
 			    HW_ATL_ITR_RES_SHIFT, res_irq);
 }
 
+/* set RSC interrupt */
+void hw_atl_itr_rsc_en_set(struct aq_hw_s *aq_hw, u32 enable)
+{
+	aq_hw_write_reg(aq_hw, HW_ATL_ITR_RSC_EN_ADR, enable);
+}
+
+/* set RSC delay */
+void hw_atl_itr_rsc_delay_set(struct aq_hw_s *aq_hw, u32 delay)
+{
+	aq_hw_write_reg_bit(aq_hw, HW_ATL_ITR_RSC_DELAY_ADR,
+			    HW_ATL_ITR_RSC_DELAY_MSK,
+			    HW_ATL_ITR_RSC_DELAY_SHIFT,
+			    delay);
+}
+
 /* rdm */
 void hw_atl_rdm_cpu_id_set(struct aq_hw_s *aq_hw, u32 cpuid, u32 dca)
 {

drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_llh.h

@@ -152,6 +152,12 @@ u32 hw_atl_itr_res_irq_get(struct aq_hw_s *aq_hw);
 /* set reset interrupt */
 void hw_atl_itr_res_irq_set(struct aq_hw_s *aq_hw, u32 res_irq);
 
+/* set RSC interrupt */
+void hw_atl_itr_rsc_en_set(struct aq_hw_s *aq_hw, u32 enable);
+
+/* set RSC delay */
+void hw_atl_itr_rsc_delay_set(struct aq_hw_s *aq_hw, u32 delay);
+
 /* rdm */
 
 /* set cpu id */

drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_llh_internal.h

@@ -95,6 +95,19 @@
 #define HW_ATL_ITR_RES_MSK 0x80000000
 /* lower bit position of bitfield itr_reset */
 #define HW_ATL_ITR_RES_SHIFT 31
+
+/* register address for bitfield  rsc_en */
+#define HW_ATL_ITR_RSC_EN_ADR 0x00002200
+
+/* register address for bitfield  rsc_delay */
+#define HW_ATL_ITR_RSC_DELAY_ADR 0x00002204
+/* bitmask for bitfield  rsc_delay */
+#define HW_ATL_ITR_RSC_DELAY_MSK 0x0000000f
+/* width of bitfield  rsc_delay */
+#define HW_ATL_ITR_RSC_DELAY_WIDTH 4
+/* lower bit position of bitfield  rsc_delay */
+#define HW_ATL_ITR_RSC_DELAY_SHIFT 0
+
 /* register address for bitfield dca{d}_cpuid[7:0] */
 #define HW_ATL_RDM_DCADCPUID_ADR(dca) (0x00006100 + (dca) * 0x4)
 /* bitmask for bitfield dca{d}_cpuid[7:0] */