// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 1999 - 2008 Intel Corporation. */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include "ixgb_hw.h"
#include "ixgb_ee.h"
/* Local prototypes */
static u16 ixgb_shift_in_bits(struct ixgb_hw *hw);

static void ixgb_shift_out_bits(struct ixgb_hw *hw,
                                u16 data,
                                u16 count);
static void ixgb_standby_eeprom(struct ixgb_hw *hw);

static bool ixgb_wait_eeprom_command(struct ixgb_hw *hw);

static void ixgb_cleanup_eeprom(struct ixgb_hw *hw);

/******************************************************************************
 * Raises the EEPROM's clock input.
 *
 * hw - Struct containing variables accessed by shared code
 * eecd_reg - EECD's current value
 *****************************************************************************/
static void
ixgb_raise_clock(struct ixgb_hw *hw,
                  u32 *eecd_reg)
{
        /* Raise the clock input to the EEPROM (by setting the SK bit), and then
         *  wait 50 microseconds.
         */
        *eecd_reg = *eecd_reg | IXGB_EECD_SK;
        IXGB_WRITE_REG(hw, EECD, *eecd_reg);
        IXGB_WRITE_FLUSH(hw);
        udelay(50);
}

/******************************************************************************
 * Lowers the EEPROM's clock input.
 *
 * hw - Struct containing variables accessed by shared code
 * eecd_reg - EECD's current value
 *****************************************************************************/
static void
ixgb_lower_clock(struct ixgb_hw *hw,
                  u32 *eecd_reg)
{
        /* Lower the clock input to the EEPROM (by clearing the SK bit), and then
         * wait 50 microseconds.
         */
        *eecd_reg = *eecd_reg & ~IXGB_EECD_SK;
        IXGB_WRITE_REG(hw, EECD, *eecd_reg);
        IXGB_WRITE_FLUSH(hw);
        udelay(50);
}

/******************************************************************************
 * Shift data bits out to the EEPROM.
 *
 * hw - Struct containing variables accessed by shared code
 * data - data to send to the EEPROM
 * count - number of bits to shift out
 *****************************************************************************/
static void
ixgb_shift_out_bits(struct ixgb_hw *hw,
                                         u16 data,
                                         u16 count)
{
        u32 eecd_reg;
        u32 mask;

        /* We need to shift "count" bits out to the EEPROM. So, value in the
         * "data" parameter will be shifted out to the EEPROM one bit at a time.
         * In order to do this, "data" must be broken down into bits.
         */
        mask = 0x01 << (count - 1);
        eecd_reg = IXGB_READ_REG(hw, EECD);
        eecd_reg &= ~(IXGB_EECD_DO | IXGB_EECD_DI);
        do {
                /* A "1" is shifted out to the EEPROM by setting bit "DI" to a "1",
                 * and then raising and then lowering the clock (the SK bit controls
                 * the clock input to the EEPROM).  A "0" is shifted out to the EEPROM
                 * by setting "DI" to "0" and then raising and then lowering the clock.
                 */
                eecd_reg &= ~IXGB_EECD_DI;

                if (data & mask)
                        eecd_reg |= IXGB_EECD_DI;

                IXGB_WRITE_REG(hw, EECD, eecd_reg);
                IXGB_WRITE_FLUSH(hw);

                udelay(50);

                ixgb_raise_clock(hw, &eecd_reg);
                ixgb_lower_clock(hw, &eecd_reg);

                mask = mask >> 1;

        } while (mask);

        /* We leave the "DI" bit set to "0" when we leave this routine. */
        eecd_reg &= ~IXGB_EECD_DI;
        IXGB_WRITE_REG(hw, EECD, eecd_reg);
}

/******************************************************************************
 * Shift data bits in from the EEPROM
 *
 * hw - Struct containing variables accessed by shared code
 *****************************************************************************/
static u16
ixgb_shift_in_bits(struct ixgb_hw *hw)
{
        u32 eecd_reg;
        u32 i;
        u16 data;

        /* In order to read a register from the EEPROM, we need to shift 16 bits
         * in from the EEPROM. Bits are "shifted in" by raising the clock input to
         * the EEPROM (setting the SK bit), and then reading the value of the "DO"
         * bit.  During this "shifting in" process the "DI" bit should always be
         * clear..
         */

        eecd_reg = IXGB_READ_REG(hw, EECD);

        eecd_reg &= ~(IXGB_EECD_DO | IXGB_EECD_DI);
        data = 0;

        for (i = 0; i < 16; i++) {
                data = data << 1;
                ixgb_raise_clock(hw, &eecd_reg);

                eecd_reg = IXGB_READ_REG(hw, EECD);

                eecd_reg &= ~(IXGB_EECD_DI);
                if (eecd_reg & IXGB_EECD_DO)
                        data |= 1;

                ixgb_lower_clock(hw, &eecd_reg);
        }

        return data;
}

/******************************************************************************
 * Prepares EEPROM for access
 *
 * hw - Struct containing variables accessed by shared code
 *
 * Lowers EEPROM clock. Clears input pin. Sets the chip select pin. This
 * function should be called before issuing a command to the EEPROM.
 *****************************************************************************/
static void
ixgb_setup_eeprom(struct ixgb_hw *hw)
{
        u32 eecd_reg;

        eecd_reg = IXGB_READ_REG(hw, EECD);

        /*  Clear SK and DI  */
        eecd_reg &= ~(IXGB_EECD_SK | IXGB_EECD_DI);
        IXGB_WRITE_REG(hw, EECD, eecd_reg);

        /*  Set CS  */
        eecd_reg |= IXGB_EECD_CS;
        IXGB_WRITE_REG(hw, EECD, eecd_reg);
}

/******************************************************************************
 * Returns EEPROM to a "standby" state
 *
 * hw - Struct containing variables accessed by shared code
 *****************************************************************************/
static void
ixgb_standby_eeprom(struct ixgb_hw *hw)
{
        u32 eecd_reg;

        eecd_reg = IXGB_READ_REG(hw, EECD);

        /*  Deselect EEPROM  */
        eecd_reg &= ~(IXGB_EECD_CS | IXGB_EECD_SK);
        IXGB_WRITE_REG(hw, EECD, eecd_reg);
        IXGB_WRITE_FLUSH(hw);
        udelay(50);

        /*  Clock high  */
        eecd_reg |= IXGB_EECD_SK;
        IXGB_WRITE_REG(hw, EECD, eecd_reg);
        IXGB_WRITE_FLUSH(hw);
        udelay(50);

        /*  Select EEPROM  */
        eecd_reg |= IXGB_EECD_CS;
        IXGB_WRITE_REG(hw, EECD, eecd_reg);
        IXGB_WRITE_FLUSH(hw);
        udelay(50);

        /*  Clock low  */
        eecd_reg &= ~IXGB_EECD_SK;
        IXGB_WRITE_REG(hw, EECD, eecd_reg);
        IXGB_WRITE_FLUSH(hw);
        udelay(50);
}

/******************************************************************************
 * Raises then lowers the EEPROM's clock pin
 *
 * hw - Struct containing variables accessed by shared code
 *****************************************************************************/
static void
ixgb_clock_eeprom(struct ixgb_hw *hw)
{
        u32 eecd_reg;

        eecd_reg = IXGB_READ_REG(hw, EECD);

        /*  Rising edge of clock  */
        eecd_reg |= IXGB_EECD_SK;
        IXGB_WRITE_REG(hw, EECD, eecd_reg);
        IXGB_WRITE_FLUSH(hw);
        udelay(50);

        /*  Falling edge of clock  */
        eecd_reg &= ~IXGB_EECD_SK;
        IXGB_WRITE_REG(hw, EECD, eecd_reg);
        IXGB_WRITE_FLUSH(hw);
        udelay(50);
}

/******************************************************************************
 * Terminates a command by lowering the EEPROM's chip select pin
 *
 * hw - Struct containing variables accessed by shared code
 *****************************************************************************/
static void
ixgb_cleanup_eeprom(struct ixgb_hw *hw)
{
        u32 eecd_reg;

        eecd_reg = IXGB_READ_REG(hw, EECD);

        eecd_reg &= ~(IXGB_EECD_CS | IXGB_EECD_DI);

        IXGB_WRITE_REG(hw, EECD, eecd_reg);

        ixgb_clock_eeprom(hw);
}

/******************************************************************************
 * Waits for the EEPROM to finish the current command.
 *
 * hw - Struct containing variables accessed by shared code
 *
 * The command is done when the EEPROM's data out pin goes high.
 *
 * Returns:
 *      true: EEPROM data pin is high before timeout.
 *      false:  Time expired.
 *****************************************************************************/
static bool
ixgb_wait_eeprom_command(struct ixgb_hw *hw)
{
        u32 eecd_reg;
        u32 i;

        /* Toggle the CS line.  This in effect tells to EEPROM to actually execute
         * the command in question.
         */
        ixgb_standby_eeprom(hw);

        /* Now read DO repeatedly until is high (equal to '1').  The EEPROM will
         * signal that the command has been completed by raising the DO signal.
         * If DO does not go high in 10 milliseconds, then error out.
         */
        for (i = 0; i < 200; i++) {
                eecd_reg = IXGB_READ_REG(hw, EECD);

                if (eecd_reg & IXGB_EECD_DO)
                        return true;

                udelay(50);
        }
        ASSERT(0);
        return false;
}

/******************************************************************************
 * Verifies that the EEPROM has a valid checksum
 *
 * hw - Struct containing variables accessed by shared code
 *
 * Reads the first 64 16 bit words of the EEPROM and sums the values read.
 * If the sum of the 64 16 bit words is 0xBABA, the EEPROM's checksum is
 * valid.
 *
 * Returns:
 *  true: Checksum is valid
 *  false: Checksum is not valid.
 *****************************************************************************/
bool
ixgb_validate_eeprom_checksum(struct ixgb_hw *hw)
{
        u16 checksum = 0;
        u16 i;

        for (i = 0; i < (EEPROM_CHECKSUM_REG + 1); i++)
                checksum += ixgb_read_eeprom(hw, i);

        if (checksum == (u16) EEPROM_SUM)
                return true;
        else
                return false;
}

/******************************************************************************
 * Calculates the EEPROM checksum and writes it to the EEPROM
 *
 * hw - Struct containing variables accessed by shared code
 *
 * Sums the first 63 16 bit words of the EEPROM. Subtracts the sum from 0xBABA.
 * Writes the difference to word offset 63 of the EEPROM.
 *****************************************************************************/
void
ixgb_update_eeprom_checksum(struct ixgb_hw *hw)
{
        u16 checksum = 0;
        u16 i;

        for (i = 0; i < EEPROM_CHECKSUM_REG; i++)
                checksum += ixgb_read_eeprom(hw, i);

        checksum = (u16) EEPROM_SUM - checksum;

        ixgb_write_eeprom(hw, EEPROM_CHECKSUM_REG, checksum);
}

/******************************************************************************
 * Writes a 16 bit word to a given offset in the EEPROM.
 *
 * hw - Struct containing variables accessed by shared code
 * reg - offset within the EEPROM to be written to
 * data - 16 bit word to be written to the EEPROM
 *
 * If ixgb_update_eeprom_checksum is not called after this function, the
 * EEPROM will most likely contain an invalid checksum.
 *
 *****************************************************************************/
void
ixgb_write_eeprom(struct ixgb_hw *hw, u16 offset, u16 data)
{
        struct ixgb_ee_map_type *ee_map = (struct ixgb_ee_map_type *)hw->eeprom;

        /* Prepare the EEPROM for writing */
        ixgb_setup_eeprom(hw);

        /*  Send the 9-bit EWEN (write enable) command to the EEPROM (5-bit opcode
         *  plus 4-bit dummy).  This puts the EEPROM into write/erase mode.
         */
        ixgb_shift_out_bits(hw, EEPROM_EWEN_OPCODE, 5);
        ixgb_shift_out_bits(hw, 0, 4);

        /*  Prepare the EEPROM  */
        ixgb_standby_eeprom(hw);

        /*  Send the Write command (3-bit opcode + 6-bit addr)  */
        ixgb_shift_out_bits(hw, EEPROM_WRITE_OPCODE, 3);
        ixgb_shift_out_bits(hw, offset, 6);

        /*  Send the data  */
        ixgb_shift_out_bits(hw, data, 16);

        ixgb_wait_eeprom_command(hw);

        /*  Recover from write  */
        ixgb_standby_eeprom(hw);

        /* Send the 9-bit EWDS (write disable) command to the EEPROM (5-bit
         * opcode plus 4-bit dummy).  This takes the EEPROM out of write/erase
         * mode.
         */
        ixgb_shift_out_bits(hw, EEPROM_EWDS_OPCODE, 5);
        ixgb_shift_out_bits(hw, 0, 4);

        /*  Done with writing  */
        ixgb_cleanup_eeprom(hw);

        /* clear the init_ctrl_reg_1 to signify that the cache is invalidated */
        ee_map->init_ctrl_reg_1 = cpu_to_le16(EEPROM_ICW1_SIGNATURE_CLEAR);
}

/******************************************************************************
 * Reads a 16 bit word from the EEPROM.
 *
 * hw - Struct containing variables accessed by shared code
 * offset - offset of 16 bit word in the EEPROM to read
 *
 * Returns:
 *  The 16-bit value read from the eeprom
 *****************************************************************************/
u16
ixgb_read_eeprom(struct ixgb_hw *hw,
                  u16 offset)
{
        u16 data;

        /*  Prepare the EEPROM for reading  */
        ixgb_setup_eeprom(hw);

        /*  Send the READ command (opcode + addr)  */
        ixgb_shift_out_bits(hw, EEPROM_READ_OPCODE, 3);
        /*
         * We have a 64 word EEPROM, there are 6 address bits
         */
        ixgb_shift_out_bits(hw, offset, 6);

        /*  Read the data  */
        data = ixgb_shift_in_bits(hw);

        /*  End this read operation  */
        ixgb_standby_eeprom(hw);

        return data;
}

/******************************************************************************
 * Reads eeprom and stores data in shared structure.
 * Validates eeprom checksum and eeprom signature.
 *
 * hw - Struct containing variables accessed by shared code
 *
 * Returns:
 *      true: if eeprom read is successful
 *      false: otherwise.
 *****************************************************************************/
bool
ixgb_get_eeprom_data(struct ixgb_hw *hw)
{
        u16 i;
        u16 checksum = 0;
        struct ixgb_ee_map_type *ee_map;

        ENTER();

        ee_map = (struct ixgb_ee_map_type *)hw->eeprom;

        pr_debug("Reading eeprom data\n");
        for (i = 0; i < IXGB_EEPROM_SIZE ; i++) {
                u16 ee_data;
                ee_data = ixgb_read_eeprom(hw, i);
                checksum += ee_data;
                hw->eeprom[i] = cpu_to_le16(ee_data);
        }

        if (checksum != (u16) EEPROM_SUM) {
                pr_debug("Checksum invalid\n");
                /* clear the init_ctrl_reg_1 to signify that the cache is
                 * invalidated */
                ee_map->init_ctrl_reg_1 = cpu_to_le16(EEPROM_ICW1_SIGNATURE_CLEAR);
                return false;
        }

        if ((ee_map->init_ctrl_reg_1 & cpu_to_le16(EEPROM_ICW1_SIGNATURE_MASK))
                 != cpu_to_le16(EEPROM_ICW1_SIGNATURE_VALID)) {
                pr_debug("Signature invalid\n");
                return false;
        }

        return true;
}

/******************************************************************************
 * Local function to check if the eeprom signature is good
 * If the eeprom signature is good, calls ixgb)get_eeprom_data.
 *
 * hw - Struct containing variables accessed by shared code
 *
 * Returns:
 *      true: eeprom signature was good and the eeprom read was successful
 *      false: otherwise.
 ******************************************************************************/
static bool
ixgb_check_and_get_eeprom_data (struct ixgb_hw* hw)
{
        struct ixgb_ee_map_type *ee_map = (struct ixgb_ee_map_type *)hw->eeprom;

        if ((ee_map->init_ctrl_reg_1 & cpu_to_le16(EEPROM_ICW1_SIGNATURE_MASK))
            == cpu_to_le16(EEPROM_ICW1_SIGNATURE_VALID)) {
                return true;
        } else {
                return ixgb_get_eeprom_data(hw);
        }
}

/******************************************************************************
 * return a word from the eeprom
 *
 * hw - Struct containing variables accessed by shared code
 * index - Offset of eeprom word
 *
 * Returns:
 *          Word at indexed offset in eeprom, if valid, 0 otherwise.
 ******************************************************************************/
__le16
ixgb_get_eeprom_word(struct ixgb_hw *hw, u16 index)
{

        if (index < IXGB_EEPROM_SIZE && ixgb_check_and_get_eeprom_data(hw))
                return hw->eeprom[index];

        return 0;
}

/******************************************************************************
 * return the mac address from EEPROM
 *
 * hw       - Struct containing variables accessed by shared code
 * mac_addr - Ethernet Address if EEPROM contents are valid, 0 otherwise
 *
 * Returns: None.
 ******************************************************************************/
void
ixgb_get_ee_mac_addr(struct ixgb_hw *hw,
                        u8 *mac_addr)
{
        int i;
        struct ixgb_ee_map_type *ee_map = (struct ixgb_ee_map_type *)hw->eeprom;

        ENTER();

        if (ixgb_check_and_get_eeprom_data(hw)) {
                for (i = 0; i < ETH_ALEN; i++) {
                        mac_addr[i] = ee_map->mac_addr[i];
                }
                pr_debug("eeprom mac address = %pM\n", mac_addr);
        }
}


/******************************************************************************
 * return the Printed Board Assembly number from EEPROM
 *
 * hw - Struct containing variables accessed by shared code
 *
 * Returns:
 *          PBA number if EEPROM contents are valid, 0 otherwise
 ******************************************************************************/
u32
ixgb_get_ee_pba_number(struct ixgb_hw *hw)
{
        if (ixgb_check_and_get_eeprom_data(hw))
                return le16_to_cpu(hw->eeprom[EEPROM_PBA_1_2_REG])
                        | (le16_to_cpu(hw->eeprom[EEPROM_PBA_3_4_REG])<<16);

        return 0;
}


/******************************************************************************
 * return the Device Id from EEPROM
 *
 * hw - Struct containing variables accessed by shared code
 *
 * Returns:
 *          Device Id if EEPROM contents are valid, 0 otherwise
 ******************************************************************************/
u16
ixgb_get_ee_device_id(struct ixgb_hw *hw)
{
        struct ixgb_ee_map_type *ee_map = (struct ixgb_ee_map_type *)hw->eeprom;

        if (ixgb_check_and_get_eeprom_data(hw))
                return le16_to_cpu(ee_map->device_id);

        return 0;
}