[PATCH net] net: lan743x: Add set RFE read fifo threshold for PCI1x1x chips

[Raju Lakkaraju <Raju.Lakkaraju@microchip.com>]

The RFE (Receive Filtering Engine) read fifo threshold hardware default should
be overwritten to 3 for PCI1x1x Rev B0 devices to prevent lockup during some
stress tests using frames that include VLAN tags.
Rev C0 and later hardware already defaults to 3.

Fixes: bb4f6bffe33c ("net: lan743x: Add PCI11010 / PCI11414 device IDs")
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microchip.com>
---
 drivers/net/ethernet/microchip/lan743x_main.c | 17 +++++++++++++++++
 drivers/net/ethernet/microchip/lan743x_main.h |  5 +++++
 2 files changed, 22 insertions(+)

diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c
index 45e209a7d083..aec2d100ab87 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.c
+++ b/drivers/net/ethernet/microchip/lan743x_main.c
@@ -3272,6 +3272,22 @@ static void lan743x_full_cleanup(struct lan743x_adapter *adapter)
 	lan743x_pci_cleanup(adapter);
 }
 
+static int pci11x1x_set_rfe_rd_fifo_threshold(struct lan743x_adapter *adapter)
+{
+	u16 rev = adapter->csr.id_rev & ID_REV_CHIP_REV_MASK_;
+
+	if (rev == ID_REV_CHIP_REV_PCI11X1X_B0_) {
+		int misc_ctl;
+
+		misc_ctl = lan743x_csr_read(adapter, MISC_CTL_0);
+		misc_ctl &= ~MISC_CTL_0_RFE_READ_FIFO_MASK_;
+		misc_ctl |= (0x3 << MISC_CTL_0_RFE_READ_FIFO_SHIFT_);
+		lan743x_csr_write(adapter, MISC_CTL_0, misc_ctl);
+	}
+
+	return 0;
+}
+
 static int lan743x_hardware_init(struct lan743x_adapter *adapter,
 				 struct pci_dev *pdev)
 {
@@ -3287,6 +3303,7 @@ static int lan743x_hardware_init(struct lan743x_adapter *adapter,
 		pci11x1x_strap_get_status(adapter);
 		spin_lock_init(&adapter->eth_syslock_spinlock);
 		mutex_init(&adapter->sgmii_rw_lock);
+		pci11x1x_set_rfe_rd_fifo_threshold(adapter);
 	} else {
 		adapter->max_tx_channels = LAN743X_MAX_TX_CHANNELS;
 		adapter->used_tx_channels = LAN743X_USED_TX_CHANNELS;
diff --git a/drivers/net/ethernet/microchip/lan743x_main.h b/drivers/net/ethernet/microchip/lan743x_main.h
index be79cb0ae5af..be0fe52e2ae1 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.h
+++ b/drivers/net/ethernet/microchip/lan743x_main.h
@@ -26,6 +26,7 @@
 #define ID_REV_CHIP_REV_MASK_		(0x0000FFFF)
 #define ID_REV_CHIP_REV_A0_		(0x00000000)
 #define ID_REV_CHIP_REV_B0_		(0x00000010)
+#define ID_REV_CHIP_REV_PCI11X1X_B0_	(0x000000B0)
 
 #define FPGA_REV			(0x04)
 #define FPGA_REV_GET_MINOR_(fpga_rev)	(((fpga_rev) >> 8) & 0x000000FF)
@@ -311,6 +312,10 @@
 #define SGMII_CTL_LINK_STATUS_SOURCE_	BIT(8)
 #define SGMII_CTL_SGMII_POWER_DN_	BIT(1)
 
+#define MISC_CTL_0			(0x920)
+#define MISC_CTL_0_RFE_READ_FIFO_MASK_	GENMASK(6, 4)
+#define MISC_CTL_0_RFE_READ_FIFO_SHIFT_	(4)
+
 /* Vendor Specific SGMII MMD details */
 #define SR_VSMMD_PCS_ID1		0x0004
 #define SR_VSMMD_PCS_ID2		0x0005
-- 
2.34.1