/* Intel PRO/1000 Linux driver
 * Copyright(c) 1999 - 2015 Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * The full GNU General Public License is included in this distribution in
 * the file called "COPYING".
 *
 * Contact Information:
 * Linux NICS <linux.nics@intel.com>
 * e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 */

#include "e1000.h"

/**
 *  e1000_calculate_checksum - Calculate checksum for buffer
 *  @buffer: pointer to EEPROM
 *  @length: size of EEPROM to calculate a checksum for
 *
 *  Calculates the checksum for some buffer on a specified length.  The
 *  checksum calculated is returned.
 **/
static u8 e1000_calculate_checksum(u8 *buffer, u32 length)
{
	u32 i;
	u8 sum = 0;

	if (!buffer)
		return 0;

	for (i = 0; i < length; i++)
		sum += buffer[i];

	return (u8)(0 - sum);
}

/**
 *  e1000_mng_enable_host_if - Checks host interface is enabled
 *  @hw: pointer to the HW structure
 *
 *  Returns 0 upon success, else -E1000_ERR_HOST_INTERFACE_COMMAND
 *
 *  This function checks whether the HOST IF is enabled for command operation
 *  and also checks whether the previous command is completed.  It busy waits
 *  in case of previous command is not completed.
 **/
static s32 e1000_mng_enable_host_if(struct e1000_hw *hw)
{
	u32 hicr;
	u8 i;

	if (!hw->mac.arc_subsystem_valid) {
		e_dbg("ARC subsystem not valid.\n");
		return -E1000_ERR_HOST_INTERFACE_COMMAND;
	}

	/* Check that the host interface is enabled. */
	hicr = er32(HICR);
	if (!(hicr & E1000_HICR_EN)) {
		e_dbg("E1000_HOST_EN bit disabled.\n");
		return -E1000_ERR_HOST_INTERFACE_COMMAND;
	}
	/* check the previous command is completed */
	for (i = 0; i < E1000_MNG_DHCP_COMMAND_TIMEOUT; i++) {
		hicr = er32(HICR);
		if (!(hicr & E1000_HICR_C))
			break;
		mdelay(1);
	}

	if (i == E1000_MNG_DHCP_COMMAND_TIMEOUT) {
		e_dbg("Previous command timeout failed.\n");
		return -E1000_ERR_HOST_INTERFACE_COMMAND;
	}

	return 0;
}

/**
 *  e1000e_check_mng_mode_generic - Generic check management mode
 *  @hw: pointer to the HW structure
 *
 *  Reads the firmware semaphore register and returns true (>0) if
 *  manageability is enabled, else false (0).
 **/
bool e1000e_check_mng_mode_generic(struct e1000_hw *hw)
{
	u32 fwsm = er32(FWSM);

	return (fwsm & E1000_FWSM_MODE_MASK) ==
	    (E1000_MNG_IAMT_MODE << E1000_FWSM_MODE_SHIFT);
}

/**
 *  e1000e_enable_tx_pkt_filtering - Enable packet filtering on Tx
 *  @hw: pointer to the HW structure
 *
 *  Enables packet filtering on transmit packets if manageability is enabled
 *  and host interface is enabled.
 **/
bool e1000e_enable_tx_pkt_filtering(struct e1000_hw *hw)
{
	struct e1000_host_mng_dhcp_cookie *hdr = &hw->mng_cookie;
	u32 *buffer = (u32 *)&hw->mng_cookie;
	u32 offset;
	s32 ret_val, hdr_csum, csum;
	u8 i, len;

	hw->mac.tx_pkt_filtering = true;

	/* No manageability, no filtering */
	if (!hw->mac.ops.check_mng_mode(hw)) {
		hw->mac.tx_pkt_filtering = false;
		return hw->mac.tx_pkt_filtering;
	}

	/* If we can't read from the host interface for whatever
	 * reason, disable filtering.
	 */
	ret_val = e1000_mng_enable_host_if(hw);
	if (ret_val) {
		hw->mac.tx_pkt_filtering = false;
		return hw->mac.tx_pkt_filtering;
	}

	/* Read in the header.  Length and offset are in dwords. */
	len = E1000_MNG_DHCP_COOKIE_LENGTH >> 2;
	offset = E1000_MNG_DHCP_COOKIE_OFFSET >> 2;
	for (i = 0; i < len; i++)
		*(buffer + i) = E1000_READ_REG_ARRAY(hw, E1000_HOST_IF,
						     offset + i);
	hdr_csum = hdr->checksum;
	hdr->checksum = 0;
	csum = e1000_calculate_checksum((u8 *)hdr,
					E1000_MNG_DHCP_COOKIE_LENGTH);
	/* If either the checksums or signature don't match, then
	 * the cookie area isn't considered valid, in which case we
	 * take the safe route of assuming Tx filtering is enabled.
	 */
	if ((hdr_csum != csum) || (hdr->signature != E1000_IAMT_SIGNATURE)) {
		hw->mac.tx_pkt_filtering = true;
		return hw->mac.tx_pkt_filtering;
	}

	/* Cookie area is valid, make the final check for filtering. */
	if (!(hdr->status & E1000_MNG_DHCP_COOKIE_STATUS_PARSING))
		hw->mac.tx_pkt_filtering = false;

	return hw->mac.tx_pkt_filtering;
}

/**
 *  e1000_mng_write_cmd_header - Writes manageability command header
 *  @hw: pointer to the HW structure
 *  @hdr: pointer to the host interface command header
 *
 *  Writes the command header after does the checksum calculation.
 **/
static s32 e1000_mng_write_cmd_header(struct e1000_hw *hw,
				      struct e1000_host_mng_command_header *hdr)
{
	u16 i, length = sizeof(struct e1000_host_mng_command_header);

	/* Write the whole command header structure with new checksum. */

	hdr->checksum = e1000_calculate_checksum((u8 *)hdr, length);

	length >>= 2;
	/* Write the relevant command block into the ram area. */
	for (i = 0; i < length; i++) {
		E1000_WRITE_REG_ARRAY(hw, E1000_HOST_IF, i, *((u32 *)hdr + i));
		e1e_flush();
	}

	return 0;
}

/**
 *  e1000_mng_host_if_write - Write to the manageability host interface
 *  @hw: pointer to the HW structure
 *  @buffer: pointer to the host interface buffer
 *  @length: size of the buffer
 *  @offset: location in the buffer to write to
 *  @sum: sum of the data (not checksum)
 *
 *  This function writes the buffer content at the offset given on the host if.
 *  It also does alignment considerations to do the writes in most efficient
 *  way.  Also fills up the sum of the buffer in *buffer parameter.
 **/
static s32 e1000_mng_host_if_write(struct e1000_hw *hw, u8 *buffer,
				   u16 length, u16 offset, u8 *sum)
{
	u8 *tmp;
	u8 *bufptr = buffer;
	u32 data = 0;
	u16 remaining, i, j, prev_bytes;

	/* sum = only sum of the data and it is not checksum */

	if (length == 0 || offset + length > E1000_HI_MAX_MNG_DATA_LENGTH)
		return -E1000_ERR_PARAM;

	tmp = (u8 *)&data;
	prev_bytes = offset & 0x3;
	offset >>= 2;

	if (prev_bytes) {
		data = E1000_READ_REG_ARRAY(hw, E1000_HOST_IF, offset);
		for (j = prev_bytes; j < sizeof(u32); j++) {
			*(tmp + j) = *bufptr++;
			*sum += *(tmp + j);
		}
		E1000_WRITE_REG_ARRAY(hw, E1000_HOST_IF, offset, data);
		length -= j - prev_bytes;
		offset++;
	}

	remaining = length & 0x3;
	length -= remaining;

	/* Calculate length in DWORDs */
	length >>= 2;

	/* The device driver writes the relevant command block into the
	 * ram area.
	 */
	for (i = 0; i < length; i++) {
		for (j = 0; j < sizeof(u32); j++) {
			*(tmp + j) = *bufptr++;
			*sum += *(tmp + j);
		}

		E1000_WRITE_REG_ARRAY(hw, E1000_HOST_IF, offset + i, data);
	}
	if (remaining) {
		for (j = 0; j < sizeof(u32); j++) {
			if (j < remaining)
				*(tmp + j) = *bufptr++;
			else
				*(tmp + j) = 0;

			*sum += *(tmp + j);
		}
		E1000_WRITE_REG_ARRAY(hw, E1000_HOST_IF, offset + i, data);
	}

	return 0;
}

/**
 *  e1000e_mng_write_dhcp_info - Writes DHCP info to host interface
 *  @hw: pointer to the HW structure
 *  @buffer: pointer to the host interface
 *  @length: size of the buffer
 *
 *  Writes the DHCP information to the host interface.
 **/
s32 e1000e_mng_write_dhcp_info(struct e1000_hw *hw, u8 *buffer, u16 length)
{
	struct e1000_host_mng_command_header hdr;
	s32 ret_val;
	u32 hicr;

	hdr.command_id = E1000_MNG_DHCP_TX_PAYLOAD_CMD;
	hdr.command_length = length;
	hdr.reserved1 = 0;
	hdr.reserved2 = 0;
	hdr.checksum = 0;

	/* Enable the host interface */
	ret_val = e1000_mng_enable_host_if(hw);
	if (ret_val)
		return ret_val;

	/* Populate the host interface with the contents of "buffer". */
	ret_val = e1000_mng_host_if_write(hw, buffer, length,
					  sizeof(hdr), &(hdr.checksum));
	if (ret_val)
		return ret_val;

	/* Write the manageability command header */
	ret_val = e1000_mng_write_cmd_header(hw, &hdr);
	if (ret_val)
		return ret_val;

	/* Tell the ARC a new command is pending. */
	hicr = er32(HICR);
	ew32(HICR, hicr | E1000_HICR_C);

	return 0;
}

/**
 *  e1000e_enable_mng_pass_thru - Check if management passthrough is needed
 *  @hw: pointer to the HW structure
 *
 *  Verifies the hardware needs to leave interface enabled so that frames can
 *  be directed to and from the management interface.
 **/
bool e1000e_enable_mng_pass_thru(struct e1000_hw *hw)
{
	u32 manc;
	u32 fwsm, factps;

	manc = er32(MANC);

	if (!(manc & E1000_MANC_RCV_TCO_EN))
		return false;

	if (hw->mac.has_fwsm) {
		fwsm = er32(FWSM);
		factps = er32(FACTPS);

		if (!(factps & E1000_FACTPS_MNGCG) &&
		    ((fwsm & E1000_FWSM_MODE_MASK) ==
		     (e1000_mng_mode_pt << E1000_FWSM_MODE_SHIFT)))
			return true;
	} else if ((hw->mac.type == e1000_82574) ||
		   (hw->mac.type == e1000_82583)) {
		u16 data;
		s32 ret_val;

		factps = er32(FACTPS);
		ret_val = e1000_read_nvm(hw, NVM_INIT_CONTROL2_REG, 1, &data);
		if (ret_val)
			return false;

		if (!(factps & E1000_FACTPS_MNGCG) &&
		    ((data & E1000_NVM_INIT_CTRL2_MNGM) ==
		     (e1000_mng_mode_pt << 13)))
			return true;
	} else if ((manc & E1000_MANC_SMBUS_EN) &&
		   !(manc & E1000_MANC_ASF_EN)) {
		return true;
	}

	return false;
}