// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2020
 * Arthur Li, Cortina Access, arthur.li@cortina-access.com.
 */

#include <common.h>
#include <i2c.h>
#include <log.h>
#include <asm/io.h>
#include <dm.h>
#include <mapmem.h>
#include "i2c-cortina.h"

static void set_speed(struct i2c_regs *regs, int i2c_spd)
{
        union ca_biw_cfg i2c_cfg;

        i2c_cfg.wrd = readl(&regs->i2c_cfg);
        i2c_cfg.bf.core_en = 0;
        writel(i2c_cfg.wrd, &regs->i2c_cfg);

        switch (i2c_spd) {
        case IC_SPEED_MODE_FAST_PLUS:
                i2c_cfg.bf.prer = CORTINA_PER_IO_FREQ /
                                  (5 * I2C_SPEED_FAST_PLUS_RATE) - 1;
                break;

        case IC_SPEED_MODE_STANDARD:
                i2c_cfg.bf.prer = CORTINA_PER_IO_FREQ /
                                  (5 * I2C_SPEED_STANDARD_RATE) - 1;
                break;

        case IC_SPEED_MODE_FAST:
        default:
                i2c_cfg.bf.prer = CORTINA_PER_IO_FREQ /
                                  (5 * I2C_SPEED_FAST_RATE) - 1;
                break;
        }

        i2c_cfg.bf.core_en = 1;
        writel(i2c_cfg.wrd, &regs->i2c_cfg);
}

static int ca_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
{
        struct ca_i2c *priv = dev_get_priv(bus);
        int i2c_spd;

        if (speed >= I2C_SPEED_FAST_PLUS_RATE) {
                i2c_spd = IC_SPEED_MODE_FAST_PLUS;
                priv->speed = I2C_SPEED_FAST_PLUS_RATE;
        } else if (speed >= I2C_SPEED_FAST_RATE) {
                i2c_spd = IC_SPEED_MODE_FAST;
                priv->speed = I2C_SPEED_FAST_RATE;
        } else {
                i2c_spd = IC_SPEED_MODE_STANDARD;
                priv->speed = I2C_SPEED_STANDARD_RATE;
        }

        set_speed(priv->regs, i2c_spd);

        return 0;
}

static int ca_i2c_get_bus_speed(struct udevice *bus)
{
        struct ca_i2c *priv = dev_get_priv(bus);

        return priv->speed;
}

static void ca_i2c_init(struct i2c_regs *regs)
{
        union ca_biw_cfg i2c_cfg;

        i2c_cfg.wrd = readl(&regs->i2c_cfg);
        i2c_cfg.bf.core_en = 0;
        i2c_cfg.bf.biw_soft_reset = 1;
        writel(i2c_cfg.wrd, &regs->i2c_cfg);
        mdelay(10);
        i2c_cfg.bf.biw_soft_reset = 0;
        writel(i2c_cfg.wrd, &regs->i2c_cfg);

        set_speed(regs, IC_SPEED_MODE_STANDARD);

        i2c_cfg.wrd = readl(&regs->i2c_cfg);
        i2c_cfg.bf.core_en = 1;
        writel(i2c_cfg.wrd, &regs->i2c_cfg);
}

static int i2c_wait_complete(struct i2c_regs *regs)
{
        union ca_biw_ctrl i2c_ctrl;
        unsigned long start_time_bb = get_timer(0);

        i2c_ctrl.wrd = readl(&regs->i2c_ctrl);

        while (i2c_ctrl.bf.biwdone == 0) {
                i2c_ctrl.wrd = readl(&regs->i2c_ctrl);

                if (get_timer(start_time_bb) >
                   (unsigned long)(I2C_BYTE_TO_BB)) {
                        printf("%s not done!!!\n", __func__);
                        return -ETIMEDOUT;
                }
        }

        /* Clear done bit */
        writel(i2c_ctrl.wrd, &regs->i2c_ctrl);

        return 0;
}

static void i2c_setaddress(struct i2c_regs *regs, unsigned int i2c_addr,
                           int write_read)
{
        writel(i2c_addr | write_read, &regs->i2c_txr);

        writel(BIW_CTRL_START | BIW_CTRL_WRITE,
               &regs->i2c_ctrl);

        i2c_wait_complete(regs);
}

static int i2c_wait_for_bus_busy(struct i2c_regs *regs)
{
        union ca_biw_ack i2c_ack;
        unsigned long start_time_bb = get_timer(0);

        i2c_ack.wrd = readl(&regs->i2c_ack);

        while (i2c_ack.bf.biw_busy) {
                i2c_ack.wrd = readl(&regs->i2c_ack);

                if (get_timer(start_time_bb) >
                   (unsigned long)(I2C_BYTE_TO_BB)) {
                        printf("%s: timeout!\n", __func__);
                        return -ETIMEDOUT;
                }
        }

        return 0;
}

static int i2c_xfer_init(struct i2c_regs *regs, uint8_t chip, uint addr,
                         int alen, int write_read)
{
        int addr_len = alen;

        if (i2c_wait_for_bus_busy(regs))
                return 1;

        /* First cycle must write addr + offset */
        chip = ((chip & 0x7F) << 1);
        if (alen == 0 && write_read == I2C_CMD_RD)
                i2c_setaddress(regs, chip, I2C_CMD_RD);
        else
                i2c_setaddress(regs, chip, I2C_CMD_WT);

        while (alen) {
                alen--;
                writel(addr, &regs->i2c_txr);
                if (write_read == I2C_CMD_RD)
                        writel(BIW_CTRL_WRITE | BIW_CTRL_STOP,
                               &regs->i2c_ctrl);
                else
                        writel(BIW_CTRL_WRITE, &regs->i2c_ctrl);
                i2c_wait_complete(regs);
        }

        /* Send address again with Read flag if it's read command */
        if (write_read == I2C_CMD_RD && addr_len > 0)
                i2c_setaddress(regs, chip, I2C_CMD_RD);

        return 0;
}

static int i2c_xfer_finish(struct i2c_regs *regs)
{
        /* Dummy read makes bus free */
        writel(BIW_CTRL_READ | BIW_CTRL_STOP, &regs->i2c_ctrl);
        i2c_wait_complete(regs);

        if (i2c_wait_for_bus_busy(regs)) {
                printf("Timed out waiting for bus\n");
                return -ETIMEDOUT;
        }

        return 0;
}

static int ca_i2c_read(struct i2c_regs *regs, uint8_t chip, uint addr,
                       int alen, uint8_t *buffer, int len)
{
        unsigned long start_time_rx;
        int rc = 0;

        rc = i2c_xfer_init(regs, chip, addr, alen, I2C_CMD_RD);
        if (rc)
                return rc;

        start_time_rx = get_timer(0);
        while (len) {
                /* ACK_IN is ack value to send during read.
                 * ack high only on the very last byte!
                 */
                if (len == 1)
                        writel(BIW_CTRL_READ | BIW_CTRL_ACK_IN | BIW_CTRL_STOP,
                               &regs->i2c_ctrl);
                else
                        writel(BIW_CTRL_READ, &regs->i2c_ctrl);

                rc = i2c_wait_complete(regs);
                udelay(1);

                if (rc == 0) {
                        *buffer++ =
                                (uchar) readl(&regs->i2c_rxr);
                        len--;
                        start_time_rx = get_timer(0);

                } else if (get_timer(start_time_rx) > I2C_BYTE_TO) {
                        return -ETIMEDOUT;
                }
        }
        i2c_xfer_finish(regs);
        return rc;
}

static int ca_i2c_write(struct i2c_regs *regs, uint8_t chip, uint addr,
                        int alen, uint8_t *buffer, int len)
{
        int rc, nb = len;
        unsigned long start_time_tx;

        rc = i2c_xfer_init(regs, chip, addr, alen, I2C_CMD_WT);
        if (rc)
                return rc;

        start_time_tx = get_timer(0);
        while (len) {
                writel(*buffer, &regs->i2c_txr);
                if (len == 1)
                        writel(BIW_CTRL_WRITE | BIW_CTRL_STOP,
                               &regs->i2c_ctrl);
                else
                        writel(BIW_CTRL_WRITE, &regs->i2c_ctrl);

                rc = i2c_wait_complete(regs);

                if (rc == 0) {
                        len--;
                        buffer++;
                        start_time_tx = get_timer(0);
                } else if (get_timer(start_time_tx) > (nb * I2C_BYTE_TO)) {
                        return -ETIMEDOUT;
                }
        }

        return 0;
}

static int ca_i2c_probe_chip(struct udevice *bus, uint chip_addr,
                             uint chip_flags)
{
        struct ca_i2c *priv = dev_get_priv(bus);
        int ret;
        u32 tmp;

        /* Try to read the first location of the chip */
        ret = ca_i2c_read(priv->regs, chip_addr, 0, 1, (uchar *)&tmp, 1);
        if (ret)
                ca_i2c_init(priv->regs);

        return ret;
}

static int ca_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs)
{
        struct ca_i2c *priv = dev_get_priv(bus);
        int ret;

        debug("i2c_xfer: %d messages\n", nmsgs);
        for (; nmsgs > 0; nmsgs--, msg++) {
                debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
                if (msg->flags & I2C_M_RD)
                        ret = ca_i2c_read(priv->regs, msg->addr, 0, 0,
                                          msg->buf, msg->len);
                else
                        ret = ca_i2c_write(priv->regs, msg->addr, 0, 0,
                                           msg->buf, msg->len);

                if (ret) {
                        printf("i2c_xfer: %s error\n",
                               msg->flags & I2C_M_RD ? "read" : "write");
                        return ret;
                }
        }

        return 0;
}

static const struct dm_i2c_ops ca_i2c_ops = {
        .xfer           = ca_i2c_xfer,
        .probe_chip     = ca_i2c_probe_chip,
        .set_bus_speed  = ca_i2c_set_bus_speed,
        .get_bus_speed  = ca_i2c_get_bus_speed,
};

static const struct udevice_id ca_i2c_ids[] = {
        { .compatible = "cortina,ca-i2c", },
        { }
};

static int ca_i2c_probe(struct udevice *bus)
{
        struct ca_i2c *priv = dev_get_priv(bus);

        ca_i2c_init(priv->regs);

        return 0;
}

static int ca_i2c_of_to_plat(struct udevice *bus)
{
        struct ca_i2c *priv = dev_get_priv(bus);

        priv->regs = map_sysmem(dev_read_addr(bus), sizeof(struct i2c_regs));
        if (!priv->regs) {
                printf("I2C: base address is invalid\n");
                return -EINVAL;
        }

        return 0;
}

U_BOOT_DRIVER(i2c_cortina) = {
        .name   = "i2c_cortina",
        .id     = UCLASS_I2C,
        .of_match = ca_i2c_ids,
        .of_to_plat = ca_i2c_of_to_plat,
        .probe  = ca_i2c_probe,
        .priv_auto      = sizeof(struct ca_i2c),
        .ops    = &ca_i2c_ops,
        .flags  = DM_FLAG_PRE_RELOC,
};