xref: /netbsd-src/sys/dev/pci/igc/igc_mac.c (revision fb38d839b48b9b6204dbbee1672454d6e719ba01)

/*	$NetBSD: igc_mac.c,v 1.2 2023/10/04 07:35:27 rin Exp $	*/
/*	$OpenBSD: igc_mac.c,v 1.1 2021/10/31 14:52:57 patrick Exp $	*/
/*-
 * Copyright 2021 Intel Corp
 * Copyright 2021 Rubicon Communications, LLC (Netgate)
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: igc_mac.c,v 1.2 2023/10/04 07:35:27 rin Exp $");

#include <dev/pci/igc/igc_api.h>
#include <dev/mii/mii.h>

/**
 *  igc_init_mac_ops_generic - Initialize MAC function pointers
 *  @hw: pointer to the HW structure
 *
 *  Setups up the function pointers to no-op functions
 **/
void
igc_init_mac_ops_generic(struct igc_hw *hw)
{
	struct igc_mac_info *mac = &hw->mac;
	DEBUGFUNC("igc_init_mac_ops_generic");

	/* General Setup */
	mac->ops.init_params = igc_null_ops_generic;
	mac->ops.config_collision_dist = igc_config_collision_dist_generic;
	mac->ops.rar_set = igc_rar_set_generic;
}

/**
 *  igc_null_ops_generic - No-op function, returns 0
 *  @hw: pointer to the HW structure
 **/
int
igc_null_ops_generic(struct igc_hw IGC_UNUSEDARG *hw)
{
	DEBUGFUNC("igc_null_ops_generic");
	return IGC_SUCCESS;
}

/**
 *  igc_write_vfta_generic - Write value to VLAN filter table
 *  @hw: pointer to the HW structure
 *  @offset: register offset in VLAN filter table
 *  @value: register value written to VLAN filter table
 *
 *  Writes value at the given offset in the register array which stores
 *  the VLAN filter table.
 **/
void
igc_write_vfta_generic(struct igc_hw *hw, uint32_t offset, uint32_t value)
{
	DEBUGFUNC("igc_write_vfta_generic");

	IGC_WRITE_REG_ARRAY(hw, IGC_VFTA, offset, value);
	IGC_WRITE_FLUSH(hw);
}

/**
 *  igc_init_rx_addrs_generic - Initialize receive address's
 *  @hw: pointer to the HW structure
 *  @rar_count: receive address registers
 *
 *  Setup the receive address registers by setting the base receive address
 *  register to the devices MAC address and clearing all the other receive
 *  address registers to 0.
 **/
void
igc_init_rx_addrs_generic(struct igc_hw *hw, uint16_t rar_count)
{
	uint32_t i;
	uint8_t mac_addr[ETHER_ADDR_LEN] = {0};

	DEBUGFUNC("igc_init_rx_addrs_generic");

	/* Setup the receive address */
	DEBUGOUT("Programming MAC Address into RAR[0]\n");

	hw->mac.ops.rar_set(hw, hw->mac.addr, 0);

	/* Zero out the other (rar_entry_count - 1) receive addresses */
	DEBUGOUT1("Clearing RAR[1-%u]\n", rar_count-1);
	for (i = 1; i < rar_count; i++)
		hw->mac.ops.rar_set(hw, mac_addr, i);
}

/**
 *  igc_check_alt_mac_addr_generic - Check for alternate MAC addr
 *  @hw: pointer to the HW structure
 *
 *  Checks the nvm for an alternate MAC address.  An alternate MAC address
 *  can be setup by pre-boot software and must be treated like a permanent
 *  address and must override the actual permanent MAC address. If an
 *  alternate MAC address is found it is programmed into RAR0, replacing
 *  the permanent address that was installed into RAR0 by the Si on reset.
 *  This function will return SUCCESS unless it encounters an error while
 *  reading the EEPROM.
 **/
int
igc_check_alt_mac_addr_generic(struct igc_hw *hw)
{
	uint32_t i;
	int ret_val;
	uint16_t offset, nvm_alt_mac_addr_offset, nvm_data;
	uint8_t alt_mac_addr[ETHER_ADDR_LEN];

	DEBUGFUNC("igc_check_alt_mac_addr_generic");

	ret_val = hw->nvm.ops.read(hw, NVM_COMPAT, 1, &nvm_data);
	if (ret_val)
		return ret_val;

	ret_val = hw->nvm.ops.read(hw, NVM_ALT_MAC_ADDR_PTR, 1,
	    &nvm_alt_mac_addr_offset);
	if (ret_val) {
		DEBUGOUT("NVM Read Error\n");
		return ret_val;
	}

	if ((nvm_alt_mac_addr_offset == 0xFFFF) ||
	    (nvm_alt_mac_addr_offset == 0x0000))
		/* There is no Alternate MAC Address */
		return IGC_SUCCESS;

	if (hw->bus.func == IGC_FUNC_1)
		nvm_alt_mac_addr_offset += IGC_ALT_MAC_ADDRESS_OFFSET_LAN1;
	for (i = 0; i < ETHER_ADDR_LEN; i += 2) {
		offset = nvm_alt_mac_addr_offset + (i >> 1);
		ret_val = hw->nvm.ops.read(hw, offset, 1, &nvm_data);
		if (ret_val) {
			DEBUGOUT("NVM Read Error\n");
			return ret_val;
		}

		alt_mac_addr[i] = (uint8_t)(nvm_data & 0xFF);
		alt_mac_addr[i + 1] = (uint8_t)(nvm_data >> 8);
	}

	/* if multicast bit is set, the alternate address will not be used */
	if (alt_mac_addr[0] & 0x01) {
		DEBUGOUT("Ignoring Alternate Mac Address with MC bit set\n");
		return IGC_SUCCESS;
	}

	/* We have a valid alternate MAC address, and we want to treat it the
	 * same as the normal permanent MAC address stored by the HW into the
	 * RAR. Do this by mapping this address into RAR0.
	 */
	hw->mac.ops.rar_set(hw, alt_mac_addr, 0);

	return IGC_SUCCESS;
}

/**
 *  igc_rar_set_generic - Set receive address register
 *  @hw: pointer to the HW structure
 *  @addr: pointer to the receive address
 *  @index: receive address array register
 *
 *  Sets the receive address array register at index to the address passed
 *  in by addr.
 **/
int
igc_rar_set_generic(struct igc_hw *hw, uint8_t *addr, uint32_t index)
{
	uint32_t rar_low, rar_high;

	DEBUGFUNC("igc_rar_set_generic");

	/* HW expects these in little endian so we reverse the byte order
	 * from network order (big endian) to little endian
	 */
	rar_low = ((uint32_t) addr[0] | ((uint32_t) addr[1] << 8) |
	    ((uint32_t) addr[2] << 16) | ((uint32_t) addr[3] << 24));

	rar_high = ((uint32_t) addr[4] | ((uint32_t) addr[5] << 8));

	/* If MAC address zero, no need to set the AV bit */
	if (rar_low || rar_high)
		rar_high |= IGC_RAH_AV;

	/* Some bridges will combine consecutive 32-bit writes into
	 * a single burst write, which will malfunction on some parts.
	 * The flushes avoid this.
	 */
	IGC_WRITE_REG(hw, IGC_RAL(index), rar_low);
	IGC_WRITE_FLUSH(hw);
	IGC_WRITE_REG(hw, IGC_RAH(index), rar_high);
	IGC_WRITE_FLUSH(hw);

	return IGC_SUCCESS;
}

/**
 *  igc_hash_mc_addr_generic - Generate a multicast hash value
 *  @hw: pointer to the HW structure
 *  @mc_addr: pointer to a multicast address
 *
 *  Generates a multicast address hash value which is used to determine
 *  the multicast filter table array address and new table value.
 **/
int
igc_hash_mc_addr_generic(struct igc_hw *hw, uint8_t *mc_addr)
{
	uint32_t hash_value, hash_mask;
	uint8_t bit_shift = 0;

	DEBUGFUNC("igc_hash_mc_addr_generic");

	/* Register count multiplied by bits per register */
	hash_mask = (hw->mac.mta_reg_count * 32) - 1;

	/* For a mc_filter_type of 0, bit_shift is the number of left-shifts
	 * where 0xFF would still fall within the hash mask.
	 */
	while (hash_mask >> bit_shift != 0xFF)
		bit_shift++;

	/* The portion of the address that is used for the hash table
	 * is determined by the mc_filter_type setting.
	 * The algorithm is such that there is a total of 8 bits of shifting.
	 * The bit_shift for a mc_filter_type of 0 represents the number of
	 * left-shifts where the MSB of mc_addr[5] would still fall within
	 * the hash_mask.  Case 0 does this exactly.  Since there are a total
	 * of 8 bits of shifting, then mc_addr[4] will shift right the
	 * remaining number of bits. Thus 8 - bit_shift.  The rest of the
	 * cases are a variation of this algorithm...essentially raising the
	 * number of bits to shift mc_addr[5] left, while still keeping the
	 * 8-bit shifting total.
	 *
	 * For example, given the following Destination MAC Address and an
	 * mta register count of 128 (thus a 4096-bit vector and 0xFFF mask),
	 * we can see that the bit_shift for case 0 is 4.  These are the hash
	 * values resulting from each mc_filter_type...
	 * [0] [1] [2] [3] [4] [5]
	 * 01  AA  00  12  34  56
	 * LSB		 MSB
	 *
	 * case 0: hash_value = ((0x34 >> 4) | (0x56 << 4)) & 0xFFF = 0x563
	 * case 1: hash_value = ((0x34 >> 3) | (0x56 << 5)) & 0xFFF = 0xAC6
	 * case 2: hash_value = ((0x34 >> 2) | (0x56 << 6)) & 0xFFF = 0x163
	 * case 3: hash_value = ((0x34 >> 0) | (0x56 << 8)) & 0xFFF = 0x634
	 */
	switch (hw->mac.mc_filter_type) {
	default:
	case 0:
		break;
	case 1:
		bit_shift += 1;
		break;
	case 2:
		bit_shift += 2;
		break;
	case 3:
		bit_shift += 4;
		break;
	}

	hash_value = hash_mask & (((mc_addr[4] >> (8 - bit_shift)) |
	    (((uint16_t) mc_addr[5]) << bit_shift)));

	return hash_value;
}

/**
 *  igc_update_mc_addr_list_generic - Update Multicast addresses
 *  @hw: pointer to the HW structure
 *  @mc_addr_list: array of multicast addresses to program
 *  @mc_addr_count: number of multicast addresses to program
 *
 *  Updates entire Multicast Table Array.
 *  The caller must have a packed mc_addr_list of multicast addresses.
 **/
void
igc_update_mc_addr_list_generic(struct igc_hw *hw, uint8_t *mc_addr_list,
    uint32_t mc_addr_count)
{
	uint32_t hash_value, hash_bit, hash_reg;
	int i;

	DEBUGFUNC("igc_update_mc_addr_list_generic");

	/* clear mta_shadow */
	memset(&hw->mac.mta_shadow, 0, sizeof(hw->mac.mta_shadow));

	/* update mta_shadow from mc_addr_list */
	for (i = 0; (uint32_t)i < mc_addr_count; i++) {
		hash_value = igc_hash_mc_addr_generic(hw, mc_addr_list);

		hash_reg = (hash_value >> 5) & (hw->mac.mta_reg_count - 1);
		hash_bit = hash_value & 0x1F;

		hw->mac.mta_shadow[hash_reg] |= (1 << hash_bit);
		mc_addr_list += (ETHER_ADDR_LEN);
	}

	/* replace the entire MTA table */
	for (i = hw->mac.mta_reg_count - 1; i >= 0; i--)
		IGC_WRITE_REG_ARRAY(hw, IGC_MTA, i, hw->mac.mta_shadow[i]);
	IGC_WRITE_FLUSH(hw);
}

/**
 *  igc_clear_hw_cntrs_base_generic - Clear base hardware counters
 *  @hw: pointer to the HW structure
 *
 *  Clears the base hardware counters by reading the counter registers.
 **/
void
igc_clear_hw_cntrs_base_generic(struct igc_hw *hw)
{
	DEBUGFUNC("igc_clear_hw_cntrs_base_generic");

	IGC_READ_REG(hw, IGC_CRCERRS);
	IGC_READ_REG(hw, IGC_ALGNERRC);
	IGC_READ_REG(hw, IGC_MPC);
	IGC_READ_REG(hw, IGC_SCC);
	IGC_READ_REG(hw, IGC_ECOL);
	IGC_READ_REG(hw, IGC_MCC);
	IGC_READ_REG(hw, IGC_LATECOL);
	IGC_READ_REG(hw, IGC_COLC);
	IGC_READ_REG(hw, IGC_RERC);
	IGC_READ_REG(hw, IGC_DC);
	IGC_READ_REG(hw, IGC_TNCRS);
	IGC_READ_REG(hw, IGC_HTDPMC);
	IGC_READ_REG(hw, IGC_RLEC);
	IGC_READ_REG(hw, IGC_XONRXC);
	IGC_READ_REG(hw, IGC_XONTXC);
	IGC_READ_REG(hw, IGC_XOFFRXC);
	IGC_READ_REG(hw, IGC_XOFFTXC);
	IGC_READ_REG(hw, IGC_FCRUC);
	IGC_READ_REG(hw, IGC_PRC64);
	IGC_READ_REG(hw, IGC_PRC127);
	IGC_READ_REG(hw, IGC_PRC255);
	IGC_READ_REG(hw, IGC_PRC511);
	IGC_READ_REG(hw, IGC_PRC1023);
	IGC_READ_REG(hw, IGC_PRC1522);
	IGC_READ_REG(hw, IGC_GPRC);
	IGC_READ_REG(hw, IGC_BPRC);
	IGC_READ_REG(hw, IGC_MPRC);
	IGC_READ_REG(hw, IGC_GPTC);
	IGC_READ_REG(hw, IGC_GORCL);
	IGC_READ_REG(hw, IGC_GORCH);
	IGC_READ_REG(hw, IGC_GOTCL);
	IGC_READ_REG(hw, IGC_GOTCH);
	IGC_READ_REG(hw, IGC_RNBC);
	IGC_READ_REG(hw, IGC_RUC);
	IGC_READ_REG(hw, IGC_RFC);
	IGC_READ_REG(hw, IGC_ROC);
	IGC_READ_REG(hw, IGC_RJC);
	IGC_READ_REG(hw, IGC_MGTPRC);
	IGC_READ_REG(hw, IGC_MGTPDC);
	IGC_READ_REG(hw, IGC_MGTPTC);
	IGC_READ_REG(hw, IGC_TORL);
	IGC_READ_REG(hw, IGC_TORH);
	IGC_READ_REG(hw, IGC_TOTL);
	IGC_READ_REG(hw, IGC_TOTH);
	IGC_READ_REG(hw, IGC_TPR);
	IGC_READ_REG(hw, IGC_TPT);
	IGC_READ_REG(hw, IGC_PTC64);
	IGC_READ_REG(hw, IGC_PTC127);
	IGC_READ_REG(hw, IGC_PTC255);
	IGC_READ_REG(hw, IGC_PTC511);
	IGC_READ_REG(hw, IGC_PTC1023);
	IGC_READ_REG(hw, IGC_PTC1522);
	IGC_READ_REG(hw, IGC_MPTC);
	IGC_READ_REG(hw, IGC_BPTC);
	IGC_READ_REG(hw, IGC_TSCTC);
	IGC_READ_REG(hw, IGC_IAC);
	IGC_READ_REG(hw, IGC_RXDMTC);
	IGC_READ_REG(hw, IGC_HGORCL);
	IGC_READ_REG(hw, IGC_HGORCH);
	IGC_READ_REG(hw, IGC_HGOTCL);
	IGC_READ_REG(hw, IGC_HGOTCH);
	IGC_READ_REG(hw, IGC_LENERRS);
	IGC_READ_REG(hw, IGC_TLPIC);
	IGC_READ_REG(hw, IGC_RLPIC);
}

/**
 *  igc_setup_link_generic - Setup flow control and link settings
 *  @hw: pointer to the HW structure
 *
 *  Determines which flow control settings to use, then configures flow
 *  control.  Calls the appropriate media-specific link configuration
 *  function.  Assuming the adapter has a valid link partner, a valid link
 *  should be established.  Assumes the hardware has previously been reset
 *  and the transmitter and receiver are not enabled.
 **/
int
igc_setup_link_generic(struct igc_hw *hw)
{
	int ret_val;

	DEBUGFUNC("igc_setup_link_generic");

	/* In the case of the phy reset being blocked, we already have a link.
	 * We do not need to set it up again.
	 */
	if (hw->phy.ops.check_reset_block && hw->phy.ops.check_reset_block(hw))
		return IGC_SUCCESS;

	/* If requested flow control is set to default, set flow control
	 * for both 'rx' and 'tx' pause frames.
	 */
	if (hw->fc.requested_mode == igc_fc_default) {
		hw->fc.requested_mode = igc_fc_full;
	}

	/* Save off the requested flow control mode for use later.  Depending
	 * on the link partner's capabilities, we may or may not use this mode.
	 */
	hw->fc.current_mode = hw->fc.requested_mode;

	DEBUGOUT1("After fix-ups FlowControl is now = %x\n",
	    hw->fc.current_mode);

	/* Call the necessary media_type subroutine to configure the link. */
	ret_val = hw->mac.ops.setup_physical_interface(hw);
	if (ret_val)
		return ret_val;

	/* Initialize the flow control address, type, and PAUSE timer
	 * registers to their default values.  This is done even if flow
	 * control is disabled, because it does not hurt anything to
	 * initialize these registers.
	 */
	IGC_WRITE_REG(hw, IGC_FCT, FLOW_CONTROL_TYPE);
	IGC_WRITE_REG(hw, IGC_FCAH, FLOW_CONTROL_ADDRESS_HIGH);
	IGC_WRITE_REG(hw, IGC_FCAL, FLOW_CONTROL_ADDRESS_LOW);

	IGC_WRITE_REG(hw, IGC_FCTTV, hw->fc.pause_time);

	return igc_set_fc_watermarks_generic(hw);
}

/**
 *  igc_config_collision_dist_generic - Configure collision distance
 *  @hw: pointer to the HW structure
 *
 *  Configures the collision distance to the default value and is used
 *  during link setup.
 **/
void
igc_config_collision_dist_generic(struct igc_hw *hw)
{
	uint32_t tctl;

	DEBUGFUNC("igc_config_collision_dist_generic");

	tctl = IGC_READ_REG(hw, IGC_TCTL);

	tctl &= ~IGC_TCTL_COLD;
	tctl |= IGC_COLLISION_DISTANCE << IGC_COLD_SHIFT;

	IGC_WRITE_REG(hw, IGC_TCTL, tctl);
	IGC_WRITE_FLUSH(hw);
}

/**
 *  igc_set_fc_watermarks_generic - Set flow control high/low watermarks
 *  @hw: pointer to the HW structure
 *
 *  Sets the flow control high/low threshold (watermark) registers.  If
 *  flow control XON frame transmission is enabled, then set XON frame
 *  transmission as well.
 **/
int
igc_set_fc_watermarks_generic(struct igc_hw *hw)
{
	uint32_t fcrtl = 0, fcrth = 0;

	DEBUGFUNC("igc_set_fc_watermarks_generic");

	/* Set the flow control receive threshold registers.  Normally,
	 * these registers will be set to a default threshold that may be
	 * adjusted later by the driver's runtime code.  However, if the
	 * ability to transmit pause frames is not enabled, then these
	 * registers will be set to 0.
	 */
	if (hw->fc.current_mode & igc_fc_tx_pause) {
		/* We need to set up the Receive Threshold high and low water
		 * marks as well as (optionally) enabling the transmission of
		 * XON frames.
		 */
		fcrtl = hw->fc.low_water;
		if (hw->fc.send_xon)
			fcrtl |= IGC_FCRTL_XONE;

		fcrth = hw->fc.high_water;
	}
	IGC_WRITE_REG(hw, IGC_FCRTL, fcrtl);
	IGC_WRITE_REG(hw, IGC_FCRTH, fcrth);

	return IGC_SUCCESS;
}

/**
 *  igc_force_mac_fc_generic - Force the MAC's flow control settings
 *  @hw: pointer to the HW structure
 *
 *  Force the MAC's flow control settings.  Sets the TFCE and RFCE bits in the
 *  device control register to reflect the adapter settings.  TFCE and RFCE
 *  need to be explicitly set by software when a copper PHY is used because
 *  autonegotiation is managed by the PHY rather than the MAC.  Software must
 *  also configure these bits when link is forced on a fiber connection.
 **/
int
igc_force_mac_fc_generic(struct igc_hw *hw)
{
	uint32_t ctrl;

	DEBUGFUNC("igc_force_mac_fc_generic");

	ctrl = IGC_READ_REG(hw, IGC_CTRL);

	/* Because we didn't get link via the internal auto-negotiation
	 * mechanism (we either forced link or we got link via PHY
	 * auto-neg), we have to manually enable/disable transmit an
	 * receive flow control.
	 *
	 * The "Case" statement below enables/disable flow control
	 * according to the "hw->fc.current_mode" parameter.
	 *
	 * The possible values of the "fc" parameter are:
	 *      0:  Flow control is completely disabled
	 *      1:  Rx flow control is enabled (we can receive pause
	 *          frames but not send pause frames).
	 *      2:  Tx flow control is enabled (we can send pause frames
	 *          frames but we do not receive pause frames).
	 *      3:  Both Rx and Tx flow control (symmetric) is enabled.
	 *  other:  No other values should be possible at this point.
	 */
	DEBUGOUT1("hw->fc.current_mode = %u\n", hw->fc.current_mode);

	switch (hw->fc.current_mode) {
	case igc_fc_none:
		ctrl &= (~(IGC_CTRL_TFCE | IGC_CTRL_RFCE));
		break;
	case igc_fc_rx_pause:
		ctrl &= (~IGC_CTRL_TFCE);
		ctrl |= IGC_CTRL_RFCE;
		break;
	case igc_fc_tx_pause:
		ctrl &= (~IGC_CTRL_RFCE);
		ctrl |= IGC_CTRL_TFCE;
		break;
	case igc_fc_full:
		ctrl |= (IGC_CTRL_TFCE | IGC_CTRL_RFCE);
		break;
	default:
		DEBUGOUT("Flow control param set incorrectly\n");
		return -IGC_ERR_CONFIG;
	}

	IGC_WRITE_REG(hw, IGC_CTRL, ctrl);

	return IGC_SUCCESS;
}

/**
 *  igc_config_fc_after_link_up_generic - Configures flow control after link
 *  @hw: pointer to the HW structure
 *
 *  Checks the status of auto-negotiation after link up to ensure that the
 *  speed and duplex were not forced.  If the link needed to be forced, then
 *  flow control needs to be forced also.  If auto-negotiation is enabled
 *  and did not fail, then we configure flow control based on our link
 *  partner.
 **/
int
igc_config_fc_after_link_up_generic(struct igc_hw *hw)
{
	struct igc_mac_info *mac = &hw->mac;
	uint16_t mii_status_reg, mii_nway_adv_reg, mii_nway_lp_ability_reg;
	uint16_t speed, duplex;
	int ret_val = IGC_SUCCESS;

	DEBUGFUNC("igc_config_fc_after_link_up_generic");

	if (ret_val) {
		DEBUGOUT("Error forcing flow control settings\n");
		return ret_val;
	}

	/* Check for the case where we have copper media and auto-neg is
	 * enabled.  In this case, we need to check and see if Auto-Neg
	 * has completed, and if so, how the PHY and link partner has
	 * flow control configured.
	 */
	if (mac->autoneg) {
		/* Read the MII Status Register and check to see if AutoNeg
		 * has completed.  We read this twice because this reg has
		 * some "sticky" (latched) bits.
		 */
		ret_val = hw->phy.ops.read_reg(hw, MII_BMSR, &mii_status_reg);
		if (ret_val)
			return ret_val;
		ret_val = hw->phy.ops.read_reg(hw, MII_BMSR, &mii_status_reg);
		if (ret_val)
			return ret_val;

		if (!(mii_status_reg & MII_SR_AUTONEG_COMPLETE))
			return ret_val;

		/* The AutoNeg process has completed, so we now need to
		 * read both the Auto Negotiation Advertisement
		 * Register (Address 4) and the Auto_Negotiation Base
		 * Page Ability Register (Address 5) to determine how
		 * flow control was negotiated.
		 */
		ret_val = hw->phy.ops.read_reg(hw, PHY_AUTONEG_ADV,
		    &mii_nway_adv_reg);
		if (ret_val)
			return ret_val;
		ret_val = hw->phy.ops.read_reg(hw, PHY_LP_ABILITY,
		    &mii_nway_lp_ability_reg);
		if (ret_val)
			return ret_val;

		/* Two bits in the Auto Negotiation Advertisement Register
		 * (Address 4) and two bits in the Auto Negotiation Base
		 * Page Ability Register (Address 5) determine flow control
		 * for both the PHY and the link partner.  The following
		 * table, taken out of the IEEE 802.3ab/D6.0 dated March 25,
		 * 1999, describes these PAUSE resolution bits and how flow
		 * control is determined based upon these settings.
		 * NOTE:  DC = Don't Care
		 *
		 *   LOCAL DEVICE  |   LINK PARTNER
		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | NIC Resolution
		 *-------|---------|-------|---------|--------------------
		 *   0   |    0    |  DC   |   DC    | igc_fc_none
		 *   0   |    1    |   0   |   DC    | igc_fc_none
		 *   0   |    1    |   1   |    0    | igc_fc_none
		 *   0   |    1    |   1   |    1    | igc_fc_tx_pause
		 *   1   |    0    |   0   |   DC    | igc_fc_none
		 *   1   |   DC    |   1   |   DC    | igc_fc_full
		 *   1   |    1    |   0   |    0    | igc_fc_none
		 *   1   |    1    |   0   |    1    | igc_fc_rx_pause
		 *
		 * Are both PAUSE bits set to 1?  If so, this implies
		 * Symmetric Flow Control is enabled at both ends.  The
		 * ASM_DIR bits are irrelevant per the spec.
		 *
		 * For Symmetric Flow Control:
		 *
		 *   LOCAL DEVICE  |   LINK PARTNER
		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | Result
		 *-------|---------|-------|---------|--------------------
		 *   1   |   DC    |   1   |   DC    | IGC_fc_full
		 *
		 */
		if ((mii_nway_adv_reg & NWAY_AR_PAUSE) &&
		    (mii_nway_lp_ability_reg & NWAY_LPAR_PAUSE)) {
			/* Now we need to check if the user selected Rx ONLY
			 * of pause frames.  In this case, we had to advertise
			 * FULL flow control because we could not advertise Rx
			 * ONLY. Hence, we must now check to see if we need to
			 * turn OFF the TRANSMISSION of PAUSE frames.
			 */
			if (hw->fc.requested_mode == igc_fc_full)
				hw->fc.current_mode = igc_fc_full;
			else
				hw->fc.current_mode = igc_fc_rx_pause;
		}
		/* For receiving PAUSE frames ONLY.
		 *
		 *   LOCAL DEVICE  |   LINK PARTNER
		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | Result
		 *-------|---------|-------|---------|--------------------
		 *   0   |    1    |   1   |    1    | igc_fc_tx_pause
		 */
		else if (!(mii_nway_adv_reg & NWAY_AR_PAUSE) &&
			  (mii_nway_adv_reg & NWAY_AR_ASM_DIR) &&
			  (mii_nway_lp_ability_reg & NWAY_LPAR_PAUSE) &&
			  (mii_nway_lp_ability_reg & NWAY_LPAR_ASM_DIR)) {
				hw->fc.current_mode = igc_fc_tx_pause;
		}
		/* For transmitting PAUSE frames ONLY.
		 *
		 *   LOCAL DEVICE  |   LINK PARTNER
		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | Result
		 *-------|---------|-------|---------|--------------------
		 *   1   |    1    |   0   |    1    | igc_fc_rx_pause
		 */
		else if ((mii_nway_adv_reg & NWAY_AR_PAUSE) &&
			 (mii_nway_adv_reg & NWAY_AR_ASM_DIR) &&
			 !(mii_nway_lp_ability_reg & NWAY_LPAR_PAUSE) &&
			 (mii_nway_lp_ability_reg & NWAY_LPAR_ASM_DIR)) {
				hw->fc.current_mode = igc_fc_rx_pause;
		} else {
			/* Per the IEEE spec, at this point flow control
			 * should be disabled.
			 */
			hw->fc.current_mode = igc_fc_none;
			DEBUGOUT("Flow Control = NONE.\n");
		}

		/* Now we need to do one last check...  If we auto-
		 * negotiated to HALF DUPLEX, flow control should not be
		 * enabled per IEEE 802.3 spec.
		 */
		ret_val = mac->ops.get_link_up_info(hw, &speed, &duplex);
		if (ret_val) {
			DEBUGOUT("Error getting link speed and duplex\n");
			return ret_val;
		}

		if (duplex == HALF_DUPLEX)
			hw->fc.current_mode = igc_fc_none;

		/* Now we call a subroutine to actually force the MAC
		 * controller to use the correct flow control settings.
		 */
		ret_val = igc_force_mac_fc_generic(hw);
		if (ret_val) {
			DEBUGOUT("Error forcing flow control settings\n");
			return ret_val;
		}
	}

	return IGC_SUCCESS;
}

/**
 *  igc_get_speed_and_duplex_copper_generic - Retrieve current speed/duplex
 *  @hw: pointer to the HW structure
 *  @speed: stores the current speed
 *  @duplex: stores the current duplex
 *
 *  Read the status register for the current speed/duplex and store the current
 *  speed and duplex for copper connections.
 **/
int
igc_get_speed_and_duplex_copper_generic(struct igc_hw *hw, uint16_t *speed,
    uint16_t *duplex)
{
	uint32_t status;

	DEBUGFUNC("igc_get_speed_and_duplex_copper_generic");

	status = IGC_READ_REG(hw, IGC_STATUS);
	if (status & IGC_STATUS_SPEED_1000) {
		/* For I225, STATUS will indicate 1G speed in both 1 Gbps
		 * and 2.5 Gbps link modes. An additional bit is used
		 * to differentiate between 1 Gbps and 2.5 Gbps.
		 */
		if ((hw->mac.type == igc_i225) &&
		    (status & IGC_STATUS_SPEED_2500)) {
			*speed = SPEED_2500;
			DEBUGOUT("2500 Mbs, ");
		} else {
			*speed = SPEED_1000;
			DEBUGOUT("1000 Mbs, ");
		}
	} else if (status & IGC_STATUS_SPEED_100) {
		*speed = SPEED_100;
		DEBUGOUT("100 Mbs, ");
	} else {
		*speed = SPEED_10;
		DEBUGOUT("10 Mbs, ");
	}

	if (status & IGC_STATUS_FD) {
		*duplex = FULL_DUPLEX;
		DEBUGOUT("Full Duplex\n");
	} else {
		*duplex = HALF_DUPLEX;
		DEBUGOUT("Half Duplex\n");
	}

	return IGC_SUCCESS;
}

/**
 *  igc_put_hw_semaphore_generic - Release hardware semaphore
 *  @hw: pointer to the HW structure
 *
 *  Release hardware semaphore used to access the PHY or NVM
 **/
void
igc_put_hw_semaphore_generic(struct igc_hw *hw)
{
	uint32_t swsm;

        DEBUGFUNC("igc_put_hw_semaphore_generic");

	swsm = IGC_READ_REG(hw, IGC_SWSM);
	swsm &= ~(IGC_SWSM_SMBI | IGC_SWSM_SWESMBI);

	IGC_WRITE_REG(hw, IGC_SWSM, swsm);
}

/**
 *  igc_get_auto_rd_done_generic - Check for auto read completion
 *  @hw: pointer to the HW structure
 *
 *  Check EEPROM for Auto Read done bit.
 **/
int
igc_get_auto_rd_done_generic(struct igc_hw *hw)
{
	int i = 0;

	DEBUGFUNC("igc_get_auto_rd_done_generic");

	while (i < AUTO_READ_DONE_TIMEOUT) {
		if (IGC_READ_REG(hw, IGC_EECD) & IGC_EECD_AUTO_RD)
			break;
		msec_delay(1);
		i++;
	}

	if (i == AUTO_READ_DONE_TIMEOUT) {
		DEBUGOUT("Auto read by HW from NVM has not completed.\n");
		return -IGC_ERR_RESET;
	}

	return IGC_SUCCESS;
}

/**
 *  igc_disable_pcie_master_generic - Disables PCI-express master access
 *  @hw: pointer to the HW structure
 *
 *  Returns IGC_SUCCESS if successful, else returns -10
 *  (-IGC_ERR_MASTER_REQUESTS_PENDING) if master disable bit has not caused
 *  the master requests to be disabled.
 *
 *  Disables PCI-Express master access and verifies there are no pending
 *  requests.
 **/
int
igc_disable_pcie_master_generic(struct igc_hw *hw)
{
	uint32_t ctrl;
	int timeout = MASTER_DISABLE_TIMEOUT;

	DEBUGFUNC("igc_disable_pcie_master_generic");

	ctrl = IGC_READ_REG(hw, IGC_CTRL);
	ctrl |= IGC_CTRL_GIO_MASTER_DISABLE;
	IGC_WRITE_REG(hw, IGC_CTRL, ctrl);

	while (timeout) {
		if (!(IGC_READ_REG(hw, IGC_STATUS) &
		    IGC_STATUS_GIO_MASTER_ENABLE))
			break;
		DELAY(100);
		timeout--;
	}

	if (!timeout) {
		DEBUGOUT("Master requests are pending.\n");
		return -IGC_ERR_MASTER_REQUESTS_PENDING;
	}

	return IGC_SUCCESS;
}