[PATCH v1 1/6] net/r8169: disable RX CRC drop for RTL8125BP and later

[Howard Wang]

When RX drop CRC is enabled, the hardware will not DMA the RX CRC,
and the packet length in the RX descriptor will not include the CRC
length.
Other OS drivers might leave this feature enabled instead of disabling
it during their shutdown sequence. To avoid driver conflicts and
unexpected behavior upon reboot or driver reload, explicitly disable
this feature for RTL8125BP and all subsequent MAC versions.

Signed-off-by: Howard Wang <howard_wang at realsil.com.cn>
---
 drivers/net/r8169/r8169_compat.h |  1 +
 drivers/net/r8169/r8169_hw.c     | 25 +++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/drivers/net/r8169/r8169_compat.h b/drivers/net/r8169/r8169_compat.h
index 91c84c7633..28f0bfc246 100644
--- a/drivers/net/r8169/r8169_compat.h
+++ b/drivers/net/r8169/r8169_compat.h
@@ -347,6 +347,7 @@ enum RTL_register_content {
 	RxCfg_pause_slot_en = (1 << 11),
 	RxCfg_9356SEL       = (1 << 6),
 	EnableRxDescV4_0    = (1 << 1), /* Not in rcr */
+	RX_CRC_DROP_EN      = (1 << 0),
 
 	/* TX config bits */
 	TxInterFrameGapShift = 24,
diff --git a/drivers/net/r8169/r8169_hw.c b/drivers/net/r8169/r8169_hw.c
index 27d52c81c9..e5434165ba 100644
--- a/drivers/net/r8169/r8169_hw.c
+++ b/drivers/net/r8169/r8169_hw.c
@@ -911,6 +911,29 @@ rtl8125_set_rx_desc_type(struct rtl_hw *hw)
 	}
 }
 
+static void
+rtl8125_set_rx_crc_drop(struct rtl_hw *hw, bool enable)
+{
+	switch (hw->mcfg) {
+	case CFG_METHOD_54:
+	case CFG_METHOD_55:
+	case CFG_METHOD_56:
+	case CFG_METHOD_57:
+	case CFG_METHOD_58:
+	case CFG_METHOD_59:
+	case CFG_METHOD_60:
+	case CFG_METHOD_61:
+	case CFG_METHOD_70:
+	case CFG_METHOD_71:
+	case CFG_METHOD_91:
+		if (enable)
+			RTL_W8(hw, 0xD8, RTL_R8(hw, 0xD8) | RX_CRC_DROP_EN);
+		else
+			RTL_W8(hw, 0xD8, RTL_R8(hw, 0xD8) & ~RX_CRC_DROP_EN);
+		break;
+	}
+}
+
 static void
 rtl8125_hw_config(struct rtl_hw *hw)
 {
@@ -967,6 +990,8 @@ rtl8125_hw_config(struct rtl_hw *hw)
 
 	rtl8125_set_rx_desc_type(hw);
 
+	rtl8125_set_rx_crc_drop(hw, false);
+
 	if (hw->mcfg == CFG_METHOD_58 || hw->mcfg == CFG_METHOD_91) {
 		rtl_clear_mac_ocp_bit(hw, 0xE00C, BIT_12);
 		rtl_clear_mac_ocp_bit(hw, 0xC0C2, BIT_6);
-- 
2.43.0