Fix i217 PHY initialization

Add a workaround for a hardware bug were receiving of packets would stop
until the battery of the laptop was removed. The problem could be
triggered if the LAN cable was plugged in after the PHY had already been
initialized.

The workaround is already present in FreeBSD (e1000_ich8lan.c:
e1000_lv_jumbo_workaround_ich8lan()) and Linux. The commit messages of
b20a7744 and da1e2046 in Linux have some more details.

Found and ported from FreeBSD by Valentin Dornauer.

Tested by many.

ok deraadt@

1 files changed, 97 insertions, 1 deletions

diff --git a/sys/dev/pci/if_em_hw.c b/sys/dev/pci/if_em_hw.c
index 9e9eef946c2..5f279bcbd64 100644
--- a/sys/dev/pci/if_em_hw.c
+++ b/sys/dev/pci/if_em_hw.c
@@ -31,7 +31,7 @@
 
 *******************************************************************************/
 
-/* $OpenBSD: if_em_hw.c,v 1.86 2015/07/17 16:56:34 yuo Exp $ */
+/* $OpenBSD: if_em_hw.c,v 1.87 2015/08/05 18:31:14 sf Exp $ */
 /*
  * if_em_hw.c Shared functions for accessing and configuring the MAC
  */
@@ -91,6 +91,7 @@ static int32_t	em_id_led_init(struct em_hw *);
 static int32_t	em_init_lcd_from_nvm_config_region(struct em_hw *,  uint32_t,
 		    uint32_t);
 static int32_t	em_init_lcd_from_nvm(struct em_hw *);
+static int32_t	em_phy_no_cable_workaround(struct em_hw *);
 static void	em_init_rx_addrs(struct em_hw *);
 static void	em_initialize_hardware_bits(struct em_hw *);
 static boolean_t em_is_onboard_nvm_eeprom(struct em_hw *);
@@ -7018,6 +7019,96 @@ em_read_mac_addr(struct em_hw *hw)
 }
 
 /******************************************************************************
+ * Explicitly disables jumbo frames and resets some PHY registers back to hw-
+ * defaults. This is necessary in case the ethernet cable was inserted AFTER
+ * the firmware initialized the PHY. Otherwise it is left in a state where
+ * it is possible to transmit but not receive packets. Observed on I217-LM and
+ * fixed in FreeBSD's sys/dev/e1000/e1000_ich8lan.c.
+ *
+ * hw - Struct containing variables accessed by shared code
+ *****************************************************************************/
+STATIC int32_t
+em_phy_no_cable_workaround(struct em_hw *hw) {
+	int32_t ret_val, dft_ret_val;
+	uint32_t mac_reg;
+	uint16_t data, phy_reg;
+
+	/* disable Rx path while enabling workaround */
+	em_read_phy_reg(hw, I2_DFT_CTRL, &phy_reg);
+	ret_val = em_write_phy_reg(hw, I2_DFT_CTRL, phy_reg | (1 << 14));
+	if (ret_val)
+		return ret_val;
+
+	/* Write MAC register values back to h/w defaults */
+	mac_reg = E1000_READ_REG(hw, FFLT_DBG);
+	mac_reg &= ~(0xF << 14);
+	E1000_WRITE_REG(hw, FFLT_DBG, mac_reg);
+
+	mac_reg = E1000_READ_REG(hw, RCTL);
+	mac_reg &= ~E1000_RCTL_SECRC;
+	E1000_WRITE_REG(hw, RCTL, mac_reg);
+
+	ret_val = em_read_kmrn_reg(hw, E1000_KUMCTRLSTA_OFFSET_CTRL, &data);
+	if (ret_val)
+		goto out;
+	ret_val = em_write_kmrn_reg(hw, E1000_KUMCTRLSTA_OFFSET_CTRL,
+	    data & ~(1 << 0));
+	if (ret_val)
+		goto out;
+
+	ret_val = em_read_kmrn_reg(hw, E1000_KUMCTRLSTA_OFFSET_HD_CTRL, &data);
+	if (ret_val)
+		goto out;
+
+	data &= ~(0xF << 8);
+	data |= (0xB << 8);
+	ret_val = em_write_kmrn_reg(hw, E1000_KUMCTRLSTA_OFFSET_HD_CTRL, data);
+	if (ret_val)
+		goto out;
+
+	/* Write PHY register values back to h/w defaults */
+	em_read_phy_reg(hw, I2_SMBUS_CTRL, &data);
+	data &= ~(0x7F << 5);
+	ret_val = em_write_phy_reg(hw, I2_SMBUS_CTRL, data);
+	if (ret_val)
+		goto out;
+
+	em_read_phy_reg(hw, I2_MODE_CTRL, &data);
+	data |= (1 << 13);
+	ret_val = em_write_phy_reg(hw, I2_MODE_CTRL, data);
+	if (ret_val)
+		goto out;
+
+	/*
+	 * 776.20 and 776.23 are not documented in
+	 * i217-ethernet-controller-datasheet.pdf...
+	 */
+	em_read_phy_reg(hw, PHY_REG(776, 20), &data);
+	data &= ~(0x3FF << 2);
+	data |= (0x8 << 2);
+	ret_val = em_write_phy_reg(hw, PHY_REG(776, 20), data);
+	if (ret_val)
+		goto out;
+
+	ret_val = em_write_phy_reg(hw, PHY_REG(776, 23), 0x7E00);
+	if (ret_val)
+		goto out;
+
+	em_read_phy_reg(hw, I2_PCIE_POWER_CTRL, &data);
+	ret_val = em_write_phy_reg(hw, I2_PCIE_POWER_CTRL, data & ~(1 << 10));
+	if (ret_val)
+		goto out;
+
+out:
+	/* re-enable Rx path after enabling workaround */
+	dft_ret_val = em_write_phy_reg(hw, I2_DFT_CTRL, phy_reg & ~(1 << 14));
+	if (ret_val)
+		return ret_val;
+	else
+		return dft_ret_val;
+}
+
+/******************************************************************************
  * Initializes receive address filters.
  *
  * hw - Struct containing variables accessed by shared code
@@ -7033,6 +7124,11 @@ em_init_rx_addrs(struct em_hw *hw)
 	uint32_t rar_num;
 	DEBUGFUNC("em_init_rx_addrs");
 
+	if (hw->mac_type == em_pch_lpt || hw->mac_type == em_pch2lan)
+		if (em_phy_no_cable_workaround(hw))
+			printf(" ...failed to apply em_phy_no_cable_"
+			    "workaround.\n");
+
 	/* Setup the receive address. */
 	DEBUGOUT("Programming MAC Address into RAR[0]\n");