[dpdk-dev] [PATCH 05/28] fm10k: Add support for ITR scaling based on PCIe link speed

[Wang Xiao W <xiao.w.wang@intel.com>]

Red Rock Canyon's interrupt throttle timers are based on the PCIe link
speed. Because of this, the value being programmed into the ITR
registers must be scaled.

For the PF, this is as simple as reading the PCIe link speed and storing
the result. However, in the case of SR-IOV, the VF's interrupt throttle
timers are based on the link speed of the PF. However, the VF is unable
to get the link speed information from its configuration space, so the
PF must inform it of what scale to use.

Rather than passing this scale via mailbox message, we take advantage of
unused bits in the TDLEN register to pass the scale. It is the
responsibility of the PF to program this for the VF while setting up the
VF queues and the responsibility of the VF to get the information
accordingly. This is preferable because it allows the VF to set up the
interrupts properly during initialization and matches how the MAC
address is passed in the TDBAL/TDBAH registers.

Signed-off-by: Wang Xiao W <xiao.w.wang@intel.com>
---
 drivers/net/fm10k/base/fm10k_pf.c   | 16 +++++++++++++++-
 drivers/net/fm10k/base/fm10k_type.h |  6 ++++++
 drivers/net/fm10k/base/fm10k_vf.c   |  5 ++++-
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/net/fm10k/base/fm10k_pf.c b/drivers/net/fm10k/base/fm10k_pf.c
index bf331fc..5b66960 100644
--- a/drivers/net/fm10k/base/fm10k_pf.c
+++ b/drivers/net/fm10k/base/fm10k_pf.c
@@ -169,16 +169,21 @@ STATIC s32 fm10k_init_hw_pf(struct fm10k_hw *hw)
 				FM10K_TPH_RXCTRL_HDR_WROEN);
 	}
 
-	/* set max hold interval to align with 1.024 usec in all modes */
+	/* set max hold interval to align with 1.024 usec in all modes and
+	 * store ITR scale
+	 */
 	switch (hw->bus.speed) {
 	case fm10k_bus_speed_2500:
 		dma_ctrl = FM10K_DMA_CTRL_MAX_HOLD_1US_GEN1;
+		hw->mac.itr_scale = FM10K_TDLEN_ITR_SCALE_GEN1;
 		break;
 	case fm10k_bus_speed_5000:
 		dma_ctrl = FM10K_DMA_CTRL_MAX_HOLD_1US_GEN2;
+		hw->mac.itr_scale = FM10K_TDLEN_ITR_SCALE_GEN2;
 		break;
 	case fm10k_bus_speed_8000:
 		dma_ctrl = FM10K_DMA_CTRL_MAX_HOLD_1US_GEN3;
+		hw->mac.itr_scale = FM10K_TDLEN_ITR_SCALE_GEN3;
 		break;
 	default:
 		dma_ctrl = 0;
@@ -947,6 +952,12 @@ STATIC s32 fm10k_iov_assign_default_mac_vlan_pf(struct fm10k_hw *hw,
 	FM10K_WRITE_REG(hw, FM10K_TDBAL(vf_q_idx), tdbal);
 	FM10K_WRITE_REG(hw, FM10K_TDBAH(vf_q_idx), tdbah);
 
+	/* Provide the VF the ITR scale, using software-defined fields in TDLEN
+	 * to pass the information during VF initialization
+	 */
+	FM10K_WRITE_REG(hw, FM10K_TDLEN(vf_q_idx), hw->mac.itr_scale <<
+						   FM10K_TDLEN_ITR_SCALE_SHIFT);
+
 err_out:
 	/* configure Queue control register */
 	txqctl = ((u32)vf_vid << FM10K_TXQCTL_VID_SHIFT) &
@@ -1079,6 +1090,9 @@ STATIC s32 fm10k_iov_reset_resources_pf(struct fm10k_hw *hw,
 	for (i = queues_per_pool; i--;) {
 		FM10K_WRITE_REG(hw, FM10K_TDBAL(vf_q_idx + i), tdbal);
 		FM10K_WRITE_REG(hw, FM10K_TDBAH(vf_q_idx + i), tdbah);
+		FM10K_WRITE_REG(hw, FM10K_TDLEN(vf_q_idx + i),
+				hw->mac.itr_scale <<
+				FM10K_TDLEN_ITR_SCALE_SHIFT);
 		FM10K_WRITE_REG(hw, FM10K_TQMAP(qmap_idx + i), vf_q_idx + i);
 		FM10K_WRITE_REG(hw, FM10K_RQMAP(qmap_idx + i), vf_q_idx + i);
 	}
diff --git a/drivers/net/fm10k/base/fm10k_type.h b/drivers/net/fm10k/base/fm10k_type.h
index 534fab4..a0e5f79 100644
--- a/drivers/net/fm10k/base/fm10k_type.h
+++ b/drivers/net/fm10k/base/fm10k_type.h
@@ -344,6 +344,11 @@ struct fm10k_hw;
 #define FM10K_TDBAL(_n)		((0x40 * (_n)) + 0x8000)
 #define FM10K_TDBAH(_n)		((0x40 * (_n)) + 0x8001)
 #define FM10K_TDLEN(_n)		((0x40 * (_n)) + 0x8002)
+#define FM10K_TDLEN_ITR_SCALE_SHIFT		9
+#define FM10K_TDLEN_ITR_SCALE_MASK		0x00000E00
+#define FM10K_TDLEN_ITR_SCALE_GEN1		4
+#define FM10K_TDLEN_ITR_SCALE_GEN2		2
+#define FM10K_TDLEN_ITR_SCALE_GEN3		1
 #define FM10K_TPH_TXCTRL(_n)	((0x40 * (_n)) + 0x8003)
 #define FM10K_TPH_TXCTRL_DESC_TPHEN		0x00000020
 #define FM10K_TPH_TXCTRL_DESC_RROEN		0x00000200
@@ -680,6 +685,7 @@ struct fm10k_mac_info {
 	bool get_host_state;
 	bool tx_ready;
 	u32 dglort_map;
+	u8 itr_scale;
 };
 
 struct fm10k_swapi_table_info {
diff --git a/drivers/net/fm10k/base/fm10k_vf.c b/drivers/net/fm10k/base/fm10k_vf.c
index 76be9ab..ce42189 100644
--- a/drivers/net/fm10k/base/fm10k_vf.c
+++ b/drivers/net/fm10k/base/fm10k_vf.c
@@ -143,9 +143,12 @@ STATIC s32 fm10k_init_hw_vf(struct fm10k_hw *hw)
 	/* record maximum queue count */
 	hw->mac.max_queues = i;
 
-	/* fetch default VLAN */
+	/* fetch default VLAN and ITR scale */
 	hw->mac.default_vid = (FM10K_READ_REG(hw, FM10K_TXQCTL(0)) &
 			       FM10K_TXQCTL_VID_MASK) >> FM10K_TXQCTL_VID_SHIFT;
+	hw->mac.itr_scale = (FM10K_READ_REG(hw, FM10K_TDLEN(0)) &
+			     FM10K_TDLEN_ITR_SCALE_MASK) >>
+			    FM10K_TDLEN_ITR_SCALE_SHIFT;
 
 	return FM10K_SUCCESS;
 }
-- 
1.9.3