// SPDX-License-Identifier: GPL-2.0+
/*
 * Driver for OMAP-UART controller.
 * Based on drivers/serial/8250.c
 *
 * Copyright (C) 2010 Texas Instruments.
 *
 * Authors:
 *      Govindraj R     <govindraj.raja@ti.com>
 *      Thara Gopinath  <thara@ti.com>
 *
 * Note: This driver is made separate from 8250 driver as we cannot
 * over load 8250 driver with omap platform specific configuration for
 * features like DMA, it makes easier to implement features like DMA and
 * hardware flow control and software flow control configuration with
 * this driver as required for the omap-platform.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/serial_reg.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/serial_core.h>
#include <linux/irq.h>
#include <linux/pm_runtime.h>
#include <linux/pm_wakeirq.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/gpio/consumer.h>
#include <linux/platform_data/serial-omap.h>

#define OMAP_MAX_HSUART_PORTS   10

#define UART_BUILD_REVISION(x, y)       (((x) << 8) | (y))

#define OMAP_UART_REV_42 0x0402
#define OMAP_UART_REV_46 0x0406
#define OMAP_UART_REV_52 0x0502
#define OMAP_UART_REV_63 0x0603

#define OMAP_UART_TX_WAKEUP_EN          BIT(7)

/* Feature flags */
#define OMAP_UART_WER_HAS_TX_WAKEUP     BIT(0)

#define UART_ERRATA_i202_MDR1_ACCESS    BIT(0)
#define UART_ERRATA_i291_DMA_FORCEIDLE  BIT(1)

#define DEFAULT_CLK_SPEED 48000000 /* 48Mhz */

/* SCR register bitmasks */
#define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK               (1 << 7)
#define OMAP_UART_SCR_TX_TRIG_GRANU1_MASK               (1 << 6)
#define OMAP_UART_SCR_TX_EMPTY                  (1 << 3)

/* FCR register bitmasks */
#define OMAP_UART_FCR_RX_FIFO_TRIG_MASK                 (0x3 << 6)
#define OMAP_UART_FCR_TX_FIFO_TRIG_MASK                 (0x3 << 4)

/* MVR register bitmasks */
#define OMAP_UART_MVR_SCHEME_SHIFT      30

#define OMAP_UART_LEGACY_MVR_MAJ_MASK   0xf0
#define OMAP_UART_LEGACY_MVR_MAJ_SHIFT  4
#define OMAP_UART_LEGACY_MVR_MIN_MASK   0x0f

#define OMAP_UART_MVR_MAJ_MASK          0x700
#define OMAP_UART_MVR_MAJ_SHIFT         8
#define OMAP_UART_MVR_MIN_MASK          0x3f

#define OMAP_UART_DMA_CH_FREE   -1

#define MSR_SAVE_FLAGS          UART_MSR_ANY_DELTA
#define OMAP_MODE13X_SPEED      230400

/* WER = 0x7F
 * Enable module level wakeup in WER reg
 */
#define OMAP_UART_WER_MOD_WKUP  0x7F

/* Enable XON/XOFF flow control on output */
#define OMAP_UART_SW_TX         0x08

/* Enable XON/XOFF flow control on input */
#define OMAP_UART_SW_RX         0x02

#define OMAP_UART_SW_CLR        0xF0

#define OMAP_UART_TCR_TRIG      0x0F

struct uart_omap_dma {
        u8                      uart_dma_tx;
        u8                      uart_dma_rx;
        int                     rx_dma_channel;
        int                     tx_dma_channel;
        dma_addr_t              rx_buf_dma_phys;
        dma_addr_t              tx_buf_dma_phys;
        unsigned int            uart_base;
        /*
         * Buffer for rx dma. It is not required for tx because the buffer
         * comes from port structure.
         */
        unsigned char           *rx_buf;
        unsigned int            prev_rx_dma_pos;
        int                     tx_buf_size;
        int                     tx_dma_used;
        int                     rx_dma_used;
        spinlock_t              tx_lock;
        spinlock_t              rx_lock;
        /* timer to poll activity on rx dma */
        struct timer_list       rx_timer;
        unsigned int            rx_buf_size;
        unsigned int            rx_poll_rate;
        unsigned int            rx_timeout;
};

struct uart_omap_port {
        struct uart_port        port;
        struct uart_omap_dma    uart_dma;
        struct device           *dev;
        int                     wakeirq;

        unsigned char           ier;
        unsigned char           lcr;
        unsigned char           mcr;
        unsigned char           fcr;
        unsigned char           efr;
        unsigned char           dll;
        unsigned char           dlh;
        unsigned char           mdr1;
        unsigned char           scr;
        unsigned char           wer;

        int                     use_dma;
        /*
         * Some bits in registers are cleared on a read, so they must
         * be saved whenever the register is read, but the bits will not
         * be immediately processed.
         */
        unsigned int            lsr_break_flag;
        unsigned char           msr_saved_flags;
        char                    name[20];
        unsigned long           port_activity;
        int                     context_loss_cnt;
        u32                     errata;
        u32                     features;

        struct gpio_desc        *rts_gpiod;

        struct pm_qos_request   pm_qos_request;
        u32                     latency;
        u32                     calc_latency;
        struct work_struct      qos_work;
        bool                    is_suspending;

        unsigned int            rs485_tx_filter_count;
};

#define to_uart_omap_port(p) ((container_of((p), struct uart_omap_port, port)))

static struct uart_omap_port *ui[OMAP_MAX_HSUART_PORTS];

/* Forward declaration of functions */
static void serial_omap_mdr1_errataset(struct uart_omap_port *up, u8 mdr1);

static inline unsigned int serial_in(struct uart_omap_port *up, int offset)
{
        offset <<= up->port.regshift;
        return readw(up->port.membase + offset);
}

static inline void serial_out(struct uart_omap_port *up, int offset, int value)
{
        offset <<= up->port.regshift;
        writew(value, up->port.membase + offset);
}

static inline void serial_omap_clear_fifos(struct uart_omap_port *up)
{
        serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
        serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
                       UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
        serial_out(up, UART_FCR, 0);
}

#ifdef CONFIG_PM
static int serial_omap_get_context_loss_count(struct uart_omap_port *up)
{
        struct omap_uart_port_info *pdata = dev_get_platdata(up->dev);

        if (!pdata || !pdata->get_context_loss_count)
                return -EINVAL;

        return pdata->get_context_loss_count(up->dev);
}

/* REVISIT: Remove this when omap3 boots in device tree only mode */
static void serial_omap_enable_wakeup(struct uart_omap_port *up, bool enable)
{
        struct omap_uart_port_info *pdata = dev_get_platdata(up->dev);

        if (!pdata || !pdata->enable_wakeup)
                return;

        pdata->enable_wakeup(up->dev, enable);
}
#endif /* CONFIG_PM */

/*
 * Calculate the absolute difference between the desired and actual baud
 * rate for the given mode.
 */
static inline int calculate_baud_abs_diff(struct uart_port *port,
                                unsigned int baud, unsigned int mode)
{
        unsigned int n = port->uartclk / (mode * baud);
        int abs_diff;

        if (n == 0)
                n = 1;

        abs_diff = baud - (port->uartclk / (mode * n));
        if (abs_diff < 0)
                abs_diff = -abs_diff;

        return abs_diff;
}

/*
 * serial_omap_baud_is_mode16 - check if baud rate is MODE16X
 * @port: uart port info
 * @baud: baudrate for which mode needs to be determined
 *
 * Returns true if baud rate is MODE16X and false if MODE13X
 * Original table in OMAP TRM named "UART Mode Baud Rates, Divisor Values,
 * and Error Rates" determines modes not for all common baud rates.
 * E.g. for 1000000 baud rate mode must be 16x, but according to that
 * table it's determined as 13x.
 */
static bool
serial_omap_baud_is_mode16(struct uart_port *port, unsigned int baud)
{
        int abs_diff_13 = calculate_baud_abs_diff(port, baud, 13);
        int abs_diff_16 = calculate_baud_abs_diff(port, baud, 16);

        return (abs_diff_13 >= abs_diff_16);
}

/*
 * serial_omap_get_divisor - calculate divisor value
 * @port: uart port info
 * @baud: baudrate for which divisor needs to be calculated.
 */
static unsigned int
serial_omap_get_divisor(struct uart_port *port, unsigned int baud)
{
        unsigned int mode;

        if (!serial_omap_baud_is_mode16(port, baud))
                mode = 13;
        else
                mode = 16;
        return port->uartclk/(mode * baud);
}

static void serial_omap_enable_ms(struct uart_port *port)
{
        struct uart_omap_port *up = to_uart_omap_port(port);

        dev_dbg(up->port.dev, "serial_omap_enable_ms+%d\n", up->port.line);

        up->ier |= UART_IER_MSI;
        serial_out(up, UART_IER, up->ier);
}

static void serial_omap_stop_tx(struct uart_port *port)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        int res;

        /* Handle RS-485 */
        if (port->rs485.flags & SER_RS485_ENABLED) {
                if (up->scr & OMAP_UART_SCR_TX_EMPTY) {
                        /* THR interrupt is fired when both TX FIFO and TX
                         * shift register are empty. This means there's nothing
                         * left to transmit now, so make sure the THR interrupt
                         * is fired when TX FIFO is below the trigger level,
                         * disable THR interrupts and toggle the RS-485 GPIO
                         * data direction pin if needed.
                         */
                        up->scr &= ~OMAP_UART_SCR_TX_EMPTY;
                        serial_out(up, UART_OMAP_SCR, up->scr);
                        res = (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) ?
                                1 : 0;
                        if (up->rts_gpiod &&
                            gpiod_get_value(up->rts_gpiod) != res) {
                                if (port->rs485.delay_rts_after_send > 0)
                                        mdelay(
                                        port->rs485.delay_rts_after_send);
                                gpiod_set_value(up->rts_gpiod, res);
                        }
                } else {
                        /* We're asked to stop, but there's still stuff in the
                         * UART FIFO, so make sure the THR interrupt is fired
                         * when both TX FIFO and TX shift register are empty.
                         * The next THR interrupt (if no transmission is started
                         * in the meantime) will indicate the end of a
                         * transmission. Therefore we _don't_ disable THR
                         * interrupts in this situation.
                         */
                        up->scr |= OMAP_UART_SCR_TX_EMPTY;
                        serial_out(up, UART_OMAP_SCR, up->scr);
                        return;
                }
        }

        if (up->ier & UART_IER_THRI) {
                up->ier &= ~UART_IER_THRI;
                serial_out(up, UART_IER, up->ier);
        }
}

static void serial_omap_stop_rx(struct uart_port *port)
{
        struct uart_omap_port *up = to_uart_omap_port(port);

        up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
        up->port.read_status_mask &= ~UART_LSR_DR;
        serial_out(up, UART_IER, up->ier);
}

static void transmit_chars(struct uart_omap_port *up, unsigned int lsr)
{
        struct circ_buf *xmit = &up->port.state->xmit;
        int count;

        if (up->port.x_char) {
                serial_out(up, UART_TX, up->port.x_char);
                up->port.icount.tx++;
                up->port.x_char = 0;
                if ((up->port.rs485.flags & SER_RS485_ENABLED) &&
                    !(up->port.rs485.flags & SER_RS485_RX_DURING_TX))
                        up->rs485_tx_filter_count++;

                return;
        }
        if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
                serial_omap_stop_tx(&up->port);
                return;
        }
        count = up->port.fifosize / 4;
        do {
                serial_out(up, UART_TX, xmit->buf[xmit->tail]);
                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                up->port.icount.tx++;
                if ((up->port.rs485.flags & SER_RS485_ENABLED) &&
                    !(up->port.rs485.flags & SER_RS485_RX_DURING_TX))
                        up->rs485_tx_filter_count++;

                if (uart_circ_empty(xmit))
                        break;
        } while (--count > 0);

        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
                uart_write_wakeup(&up->port);

        if (uart_circ_empty(xmit))
                serial_omap_stop_tx(&up->port);
}

static inline void serial_omap_enable_ier_thri(struct uart_omap_port *up)
{
        if (!(up->ier & UART_IER_THRI)) {
                up->ier |= UART_IER_THRI;
                serial_out(up, UART_IER, up->ier);
        }
}

static void serial_omap_start_tx(struct uart_port *port)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        int res;

        /* Handle RS-485 */
        if (port->rs485.flags & SER_RS485_ENABLED) {
                /* Fire THR interrupts when FIFO is below trigger level */
                up->scr &= ~OMAP_UART_SCR_TX_EMPTY;
                serial_out(up, UART_OMAP_SCR, up->scr);

                /* if rts not already enabled */
                res = (port->rs485.flags & SER_RS485_RTS_ON_SEND) ? 1 : 0;
                if (up->rts_gpiod && gpiod_get_value(up->rts_gpiod) != res) {
                        gpiod_set_value(up->rts_gpiod, res);
                        if (port->rs485.delay_rts_before_send > 0)
                                mdelay(port->rs485.delay_rts_before_send);
                }
        }

        if ((port->rs485.flags & SER_RS485_ENABLED) &&
            !(port->rs485.flags & SER_RS485_RX_DURING_TX))
                up->rs485_tx_filter_count = 0;

        serial_omap_enable_ier_thri(up);
}

static void serial_omap_throttle(struct uart_port *port)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        unsigned long flags;

        spin_lock_irqsave(&up->port.lock, flags);
        up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
        serial_out(up, UART_IER, up->ier);
        spin_unlock_irqrestore(&up->port.lock, flags);
}

static void serial_omap_unthrottle(struct uart_port *port)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        unsigned long flags;

        spin_lock_irqsave(&up->port.lock, flags);
        up->ier |= UART_IER_RLSI | UART_IER_RDI;
        serial_out(up, UART_IER, up->ier);
        spin_unlock_irqrestore(&up->port.lock, flags);
}

static unsigned int check_modem_status(struct uart_omap_port *up)
{
        unsigned int status;

        status = serial_in(up, UART_MSR);
        status |= up->msr_saved_flags;
        up->msr_saved_flags = 0;
        if ((status & UART_MSR_ANY_DELTA) == 0)
                return status;

        if (status & UART_MSR_ANY_DELTA && up->ier & UART_IER_MSI &&
            up->port.state != NULL) {
                if (status & UART_MSR_TERI)
                        up->port.icount.rng++;
                if (status & UART_MSR_DDSR)
                        up->port.icount.dsr++;
                if (status & UART_MSR_DDCD)
                        uart_handle_dcd_change
                                (&up->port, status & UART_MSR_DCD);
                if (status & UART_MSR_DCTS)
                        uart_handle_cts_change
                                (&up->port, status & UART_MSR_CTS);
                wake_up_interruptible(&up->port.state->port.delta_msr_wait);
        }

        return status;
}

static void serial_omap_rlsi(struct uart_omap_port *up, unsigned int lsr)
{
        unsigned int flag;

        /*
         * Read one data character out to avoid stalling the receiver according
         * to the table 23-246 of the omap4 TRM.
         */
        if (likely(lsr & UART_LSR_DR)) {
                serial_in(up, UART_RX);
                if ((up->port.rs485.flags & SER_RS485_ENABLED) &&
                    !(up->port.rs485.flags & SER_RS485_RX_DURING_TX) &&
                    up->rs485_tx_filter_count)
                        up->rs485_tx_filter_count--;
        }

        up->port.icount.rx++;
        flag = TTY_NORMAL;

        if (lsr & UART_LSR_BI) {
                flag = TTY_BREAK;
                lsr &= ~(UART_LSR_FE | UART_LSR_PE);
                up->port.icount.brk++;
                /*
                 * We do the SysRQ and SAK checking
                 * here because otherwise the break
                 * may get masked by ignore_status_mask
                 * or read_status_mask.
                 */
                if (uart_handle_break(&up->port))
                        return;

        }

        if (lsr & UART_LSR_PE) {
                flag = TTY_PARITY;
                up->port.icount.parity++;
        }

        if (lsr & UART_LSR_FE) {
                flag = TTY_FRAME;
                up->port.icount.frame++;
        }

        if (lsr & UART_LSR_OE)
                up->port.icount.overrun++;

#ifdef CONFIG_SERIAL_OMAP_CONSOLE
        if (up->port.line == up->port.cons->index) {
                /* Recover the break flag from console xmit */
                lsr |= up->lsr_break_flag;
        }
#endif
        uart_insert_char(&up->port, lsr, UART_LSR_OE, 0, flag);
}

static void serial_omap_rdi(struct uart_omap_port *up, unsigned int lsr)
{
        unsigned char ch = 0;
        unsigned int flag;

        if (!(lsr & UART_LSR_DR))
                return;

        ch = serial_in(up, UART_RX);
        if ((up->port.rs485.flags & SER_RS485_ENABLED) &&
            !(up->port.rs485.flags & SER_RS485_RX_DURING_TX) &&
            up->rs485_tx_filter_count) {
                up->rs485_tx_filter_count--;
                return;
        }

        flag = TTY_NORMAL;
        up->port.icount.rx++;

        if (uart_handle_sysrq_char(&up->port, ch))
                return;

        uart_insert_char(&up->port, lsr, UART_LSR_OE, ch, flag);
}

/**
 * serial_omap_irq() - This handles the interrupt from one port
 * @irq: uart port irq number
 * @dev_id: uart port info
 */
static irqreturn_t serial_omap_irq(int irq, void *dev_id)
{
        struct uart_omap_port *up = dev_id;
        unsigned int iir, lsr;
        unsigned int type;
        irqreturn_t ret = IRQ_NONE;
        int max_count = 256;

        spin_lock(&up->port.lock);

        do {
                iir = serial_in(up, UART_IIR);
                if (iir & UART_IIR_NO_INT)
                        break;

                ret = IRQ_HANDLED;
                lsr = serial_in(up, UART_LSR);

                /* extract IRQ type from IIR register */
                type = iir & 0x3e;

                switch (type) {
                case UART_IIR_MSI:
                        check_modem_status(up);
                        break;
                case UART_IIR_THRI:
                        transmit_chars(up, lsr);
                        break;
                case UART_IIR_RX_TIMEOUT:
                case UART_IIR_RDI:
                        serial_omap_rdi(up, lsr);
                        break;
                case UART_IIR_RLSI:
                        serial_omap_rlsi(up, lsr);
                        break;
                case UART_IIR_CTS_RTS_DSR:
                        /* simply try again */
                        break;
                case UART_IIR_XOFF:
                default:
                        break;
                }
        } while (max_count--);

        spin_unlock(&up->port.lock);

        tty_flip_buffer_push(&up->port.state->port);

        up->port_activity = jiffies;

        return ret;
}

static unsigned int serial_omap_tx_empty(struct uart_port *port)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        unsigned long flags;
        unsigned int ret = 0;

        dev_dbg(up->port.dev, "serial_omap_tx_empty+%d\n", up->port.line);
        spin_lock_irqsave(&up->port.lock, flags);
        ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
        spin_unlock_irqrestore(&up->port.lock, flags);

        return ret;
}

static unsigned int serial_omap_get_mctrl(struct uart_port *port)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        unsigned int status;
        unsigned int ret = 0;

        status = check_modem_status(up);

        dev_dbg(up->port.dev, "serial_omap_get_mctrl+%d\n", up->port.line);

        if (status & UART_MSR_DCD)
                ret |= TIOCM_CAR;
        if (status & UART_MSR_RI)
                ret |= TIOCM_RNG;
        if (status & UART_MSR_DSR)
                ret |= TIOCM_DSR;
        if (status & UART_MSR_CTS)
                ret |= TIOCM_CTS;
        return ret;
}

static void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        unsigned char mcr = 0, old_mcr, lcr;

        dev_dbg(up->port.dev, "serial_omap_set_mctrl+%d\n", up->port.line);
        if (mctrl & TIOCM_RTS)
                mcr |= UART_MCR_RTS;
        if (mctrl & TIOCM_DTR)
                mcr |= UART_MCR_DTR;
        if (mctrl & TIOCM_OUT1)
                mcr |= UART_MCR_OUT1;
        if (mctrl & TIOCM_OUT2)
                mcr |= UART_MCR_OUT2;
        if (mctrl & TIOCM_LOOP)
                mcr |= UART_MCR_LOOP;

        old_mcr = serial_in(up, UART_MCR);
        old_mcr &= ~(UART_MCR_LOOP | UART_MCR_OUT2 | UART_MCR_OUT1 |
                     UART_MCR_DTR | UART_MCR_RTS);
        up->mcr = old_mcr | mcr;
        serial_out(up, UART_MCR, up->mcr);

        /* Turn off autoRTS if RTS is lowered; restore autoRTS if RTS raised */
        lcr = serial_in(up, UART_LCR);
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
        if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
                up->efr |= UART_EFR_RTS;
        else
                up->efr &= ~UART_EFR_RTS;
        serial_out(up, UART_EFR, up->efr);
        serial_out(up, UART_LCR, lcr);
}

static void serial_omap_break_ctl(struct uart_port *port, int break_state)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        unsigned long flags;

        dev_dbg(up->port.dev, "serial_omap_break_ctl+%d\n", up->port.line);
        spin_lock_irqsave(&up->port.lock, flags);
        if (break_state == -1)
                up->lcr |= UART_LCR_SBC;
        else
                up->lcr &= ~UART_LCR_SBC;
        serial_out(up, UART_LCR, up->lcr);
        spin_unlock_irqrestore(&up->port.lock, flags);
}

static int serial_omap_startup(struct uart_port *port)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        unsigned long flags;
        int retval;

        /*
         * Allocate the IRQ
         */
        retval = request_irq(up->port.irq, serial_omap_irq, up->port.irqflags,
                                up->name, up);
        if (retval)
                return retval;

        /* Optional wake-up IRQ */
        if (up->wakeirq) {
                retval = dev_pm_set_dedicated_wake_irq(up->dev, up->wakeirq);
                if (retval) {
                        free_irq(up->port.irq, up);
                        return retval;
                }
        }

        dev_dbg(up->port.dev, "serial_omap_startup+%d\n", up->port.line);

        pm_runtime_get_sync(up->dev);
        /*
         * Clear the FIFO buffers and disable them.
         * (they will be reenabled in set_termios())
         */
        serial_omap_clear_fifos(up);

        /*
         * Clear the interrupt registers.
         */
        (void) serial_in(up, UART_LSR);
        if (serial_in(up, UART_LSR) & UART_LSR_DR)
                (void) serial_in(up, UART_RX);
        (void) serial_in(up, UART_IIR);
        (void) serial_in(up, UART_MSR);

        /*
         * Now, initialize the UART
         */
        serial_out(up, UART_LCR, UART_LCR_WLEN8);
        spin_lock_irqsave(&up->port.lock, flags);
        /*
         * Most PC uarts need OUT2 raised to enable interrupts.
         */
        up->port.mctrl |= TIOCM_OUT2;
        serial_omap_set_mctrl(&up->port, up->port.mctrl);
        spin_unlock_irqrestore(&up->port.lock, flags);

        up->msr_saved_flags = 0;
        /*
         * Finally, enable interrupts. Note: Modem status interrupts
         * are set via set_termios(), which will be occurring imminently
         * anyway, so we don't enable them here.
         */
        up->ier = UART_IER_RLSI | UART_IER_RDI;
        serial_out(up, UART_IER, up->ier);

        /* Enable module level wake up */
        up->wer = OMAP_UART_WER_MOD_WKUP;
        if (up->features & OMAP_UART_WER_HAS_TX_WAKEUP)
                up->wer |= OMAP_UART_TX_WAKEUP_EN;

        serial_out(up, UART_OMAP_WER, up->wer);

        up->port_activity = jiffies;
        return 0;
}

static void serial_omap_shutdown(struct uart_port *port)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        unsigned long flags;

        dev_dbg(up->port.dev, "serial_omap_shutdown+%d\n", up->port.line);

        /*
         * Disable interrupts from this port
         */
        up->ier = 0;
        serial_out(up, UART_IER, 0);

        spin_lock_irqsave(&up->port.lock, flags);
        up->port.mctrl &= ~TIOCM_OUT2;
        serial_omap_set_mctrl(&up->port, up->port.mctrl);
        spin_unlock_irqrestore(&up->port.lock, flags);

        /*
         * Disable break condition and FIFOs
         */
        serial_out(up, UART_LCR, serial_in(up, UART_LCR) & ~UART_LCR_SBC);
        serial_omap_clear_fifos(up);

        /*
         * Read data port to reset things, and then free the irq
         */
        if (serial_in(up, UART_LSR) & UART_LSR_DR)
                (void) serial_in(up, UART_RX);

        pm_runtime_put_sync(up->dev);
        free_irq(up->port.irq, up);
        dev_pm_clear_wake_irq(up->dev);
}

static void serial_omap_uart_qos_work(struct work_struct *work)
{
        struct uart_omap_port *up = container_of(work, struct uart_omap_port,
                                                qos_work);

        cpu_latency_qos_update_request(&up->pm_qos_request, up->latency);
}

static void
serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
                        struct ktermios *old)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        unsigned char cval = 0;
        unsigned long flags;
        unsigned int baud, quot;

        switch (termios->c_cflag & CSIZE) {
        case CS5:
                cval = UART_LCR_WLEN5;
                break;
        case CS6:
                cval = UART_LCR_WLEN6;
                break;
        case CS7:
                cval = UART_LCR_WLEN7;
                break;
        default:
        case CS8:
                cval = UART_LCR_WLEN8;
                break;
        }

        if (termios->c_cflag & CSTOPB)
                cval |= UART_LCR_STOP;
        if (termios->c_cflag & PARENB)
                cval |= UART_LCR_PARITY;
        if (!(termios->c_cflag & PARODD))
                cval |= UART_LCR_EPAR;
        if (termios->c_cflag & CMSPAR)
                cval |= UART_LCR_SPAR;

        /*
         * Ask the core to calculate the divisor for us.
         */

        baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/13);
        quot = serial_omap_get_divisor(port, baud);

        /* calculate wakeup latency constraint */
        up->calc_latency = (USEC_PER_SEC * up->port.fifosize) / (baud / 8);
        up->latency = up->calc_latency;
        schedule_work(&up->qos_work);

        up->dll = quot & 0xff;
        up->dlh = quot >> 8;
        up->mdr1 = UART_OMAP_MDR1_DISABLE;

        up->fcr = UART_FCR_R_TRIG_01 | UART_FCR_T_TRIG_01 |
                        UART_FCR_ENABLE_FIFO;

        /*
         * Ok, we're now changing the port state. Do it with
         * interrupts disabled.
         */
        spin_lock_irqsave(&up->port.lock, flags);

        /*
         * Update the per-port timeout.
         */
        uart_update_timeout(port, termios->c_cflag, baud);

        up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
        if (termios->c_iflag & INPCK)
                up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
        if (termios->c_iflag & (BRKINT | PARMRK))
                up->port.read_status_mask |= UART_LSR_BI;

        /*
         * Characters to ignore
         */
        up->port.ignore_status_mask = 0;
        if (termios->c_iflag & IGNPAR)
                up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
        if (termios->c_iflag & IGNBRK) {
                up->port.ignore_status_mask |= UART_LSR_BI;
                /*
                 * If we're ignoring parity and break indicators,
                 * ignore overruns too (for real raw support).
                 */
                if (termios->c_iflag & IGNPAR)
                        up->port.ignore_status_mask |= UART_LSR_OE;
        }

        /*
         * ignore all characters if CREAD is not set
         */
        if ((termios->c_cflag & CREAD) == 0)
                up->port.ignore_status_mask |= UART_LSR_DR;

        /*
         * Modem status interrupts
         */
        up->ier &= ~UART_IER_MSI;
        if (UART_ENABLE_MS(&up->port, termios->c_cflag))
                up->ier |= UART_IER_MSI;
        serial_out(up, UART_IER, up->ier);
        serial_out(up, UART_LCR, cval);         /* reset DLAB */
        up->lcr = cval;
        up->scr = 0;

        /* FIFOs and DMA Settings */

        /* FCR can be changed only when the
         * baud clock is not running
         * DLL_REG and DLH_REG set to 0.
         */
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
        serial_out(up, UART_DLL, 0);
        serial_out(up, UART_DLM, 0);
        serial_out(up, UART_LCR, 0);

        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);

        up->efr = serial_in(up, UART_EFR) & ~UART_EFR_ECB;
        up->efr &= ~UART_EFR_SCD;
        serial_out(up, UART_EFR, up->efr | UART_EFR_ECB);

        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
        up->mcr = serial_in(up, UART_MCR) & ~UART_MCR_TCRTLR;
        serial_out(up, UART_MCR, up->mcr | UART_MCR_TCRTLR);
        /* FIFO ENABLE, DMA MODE */

        up->scr |= OMAP_UART_SCR_RX_TRIG_GRANU1_MASK;
        /*
         * NOTE: Setting OMAP_UART_SCR_RX_TRIG_GRANU1_MASK
         * sets Enables the granularity of 1 for TRIGGER RX
         * level. Along with setting RX FIFO trigger level
         * to 1 (as noted below, 16 characters) and TLR[3:0]
         * to zero this will result RX FIFO threshold level
         * to 1 character, instead of 16 as noted in comment
         * below.
         */

        /* Set receive FIFO threshold to 16 characters and
         * transmit FIFO threshold to 32 spaces
         */
        up->fcr &= ~OMAP_UART_FCR_RX_FIFO_TRIG_MASK;
        up->fcr &= ~OMAP_UART_FCR_TX_FIFO_TRIG_MASK;
        up->fcr |= UART_FCR6_R_TRIGGER_16 | UART_FCR6_T_TRIGGER_24 |
                UART_FCR_ENABLE_FIFO;

        serial_out(up, UART_FCR, up->fcr);
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);

        serial_out(up, UART_OMAP_SCR, up->scr);

        /* Reset UART_MCR_TCRTLR: this must be done with the EFR_ECB bit set */
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
        serial_out(up, UART_MCR, up->mcr);
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
        serial_out(up, UART_EFR, up->efr);
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);

        /* Protocol, Baud Rate, and Interrupt Settings */

        if (up->errata & UART_ERRATA_i202_MDR1_ACCESS)
                serial_omap_mdr1_errataset(up, up->mdr1);
        else
                serial_out(up, UART_OMAP_MDR1, up->mdr1);

        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
        serial_out(up, UART_EFR, up->efr | UART_EFR_ECB);

        serial_out(up, UART_LCR, 0);
        serial_out(up, UART_IER, 0);
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);

        serial_out(up, UART_DLL, up->dll);      /* LS of divisor */
        serial_out(up, UART_DLM, up->dlh);      /* MS of divisor */

        serial_out(up, UART_LCR, 0);
        serial_out(up, UART_IER, up->ier);
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);

        serial_out(up, UART_EFR, up->efr);
        serial_out(up, UART_LCR, cval);

        if (!serial_omap_baud_is_mode16(port, baud))
                up->mdr1 = UART_OMAP_MDR1_13X_MODE;
        else
                up->mdr1 = UART_OMAP_MDR1_16X_MODE;

        if (up->errata & UART_ERRATA_i202_MDR1_ACCESS)
                serial_omap_mdr1_errataset(up, up->mdr1);
        else
                serial_out(up, UART_OMAP_MDR1, up->mdr1);

        /* Configure flow control */
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);

        /* XON1/XOFF1 accessible mode B, TCRTLR=0, ECB=0 */
        serial_out(up, UART_XON1, termios->c_cc[VSTART]);
        serial_out(up, UART_XOFF1, termios->c_cc[VSTOP]);

        /* Enable access to TCR/TLR */
        serial_out(up, UART_EFR, up->efr | UART_EFR_ECB);

        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
        serial_out(up, UART_MCR, up->mcr | UART_MCR_TCRTLR);

        serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_TRIG);

        up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF);

        if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) {
                /* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */
                up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
                up->efr |= UART_EFR_CTS;
        } else {
                /* Disable AUTORTS and AUTOCTS */
                up->efr &= ~(UART_EFR_CTS | UART_EFR_RTS);
        }

        if (up->port.flags & UPF_SOFT_FLOW) {
                /* clear SW control mode bits */
                up->efr &= OMAP_UART_SW_CLR;

                /*
                 * IXON Flag:
                 * Enable XON/XOFF flow control on input.
                 * Receiver compares XON1, XOFF1.
                 */
                if (termios->c_iflag & IXON)
                        up->efr |= OMAP_UART_SW_RX;

                /*
                 * IXOFF Flag:
                 * Enable XON/XOFF flow control on output.
                 * Transmit XON1, XOFF1
                 */
                if (termios->c_iflag & IXOFF) {
                        up->port.status |= UPSTAT_AUTOXOFF;
                        up->efr |= OMAP_UART_SW_TX;
                }

                /*
                 * IXANY Flag:
                 * Enable any character to restart output.
                 * Operation resumes after receiving any
                 * character after recognition of the XOFF character
                 */
                if (termios->c_iflag & IXANY)
                        up->mcr |= UART_MCR_XONANY;
                else
                        up->mcr &= ~UART_MCR_XONANY;
        }
        serial_out(up, UART_MCR, up->mcr);
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
        serial_out(up, UART_EFR, up->efr);
        serial_out(up, UART_LCR, up->lcr);

        serial_omap_set_mctrl(&up->port, up->port.mctrl);

        spin_unlock_irqrestore(&up->port.lock, flags);
        dev_dbg(up->port.dev, "serial_omap_set_termios+%d\n", up->port.line);
}

static void
serial_omap_pm(struct uart_port *port, unsigned int state,
               unsigned int oldstate)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        unsigned char efr;

        dev_dbg(up->port.dev, "serial_omap_pm+%d\n", up->port.line);

        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
        efr = serial_in(up, UART_EFR);
        serial_out(up, UART_EFR, efr | UART_EFR_ECB);
        serial_out(up, UART_LCR, 0);

        serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0);
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
        serial_out(up, UART_EFR, efr);
        serial_out(up, UART_LCR, 0);
}

static void serial_omap_release_port(struct uart_port *port)
{
        dev_dbg(port->dev, "serial_omap_release_port+\n");
}

static int serial_omap_request_port(struct uart_port *port)
{
        dev_dbg(port->dev, "serial_omap_request_port+\n");
        return 0;
}

static void serial_omap_config_port(struct uart_port *port, int flags)
{
        struct uart_omap_port *up = to_uart_omap_port(port);

        dev_dbg(up->port.dev, "serial_omap_config_port+%d\n",
                                                        up->port.line);
        up->port.type = PORT_OMAP;
        up->port.flags |= UPF_SOFT_FLOW | UPF_HARD_FLOW;
}

static int
serial_omap_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        /* we don't want the core code to modify any port params */
        dev_dbg(port->dev, "serial_omap_verify_port+\n");
        return -EINVAL;
}

static const char *
serial_omap_type(struct uart_port *port)
{
        struct uart_omap_port *up = to_uart_omap_port(port);

        dev_dbg(up->port.dev, "serial_omap_type+%d\n", up->port.line);
        return up->name;
}

#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)

static void __maybe_unused wait_for_xmitr(struct uart_omap_port *up)
{
        unsigned int status, tmout = 10000;

        /* Wait up to 10ms for the character(s) to be sent. */
        do {
                status = serial_in(up, UART_LSR);

                if (status & UART_LSR_BI)
                        up->lsr_break_flag = UART_LSR_BI;

                if (--tmout == 0)
                        break;
                udelay(1);
        } while ((status & BOTH_EMPTY) != BOTH_EMPTY);

        /* Wait up to 1s for flow control if necessary */
        if (up->port.flags & UPF_CONS_FLOW) {
                tmout = 1000000;
                for (tmout = 1000000; tmout; tmout--) {
                        unsigned int msr = serial_in(up, UART_MSR);

                        up->msr_saved_flags |= msr & MSR_SAVE_FLAGS;
                        if (msr & UART_MSR_CTS)
                                break;

                        udelay(1);
                }
        }
}

#ifdef CONFIG_CONSOLE_POLL

static void serial_omap_poll_put_char(struct uart_port *port, unsigned char ch)
{
        struct uart_omap_port *up = to_uart_omap_port(port);

        wait_for_xmitr(up);
        serial_out(up, UART_TX, ch);
}

static int serial_omap_poll_get_char(struct uart_port *port)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        unsigned int status;

        status = serial_in(up, UART_LSR);
        if (!(status & UART_LSR_DR)) {
                status = NO_POLL_CHAR;
                goto out;
        }

        status = serial_in(up, UART_RX);

out:
        return status;
}

#endif /* CONFIG_CONSOLE_POLL */

#ifdef CONFIG_SERIAL_OMAP_CONSOLE

#ifdef CONFIG_SERIAL_EARLYCON
static unsigned int omap_serial_early_in(struct uart_port *port, int offset)
{
        offset <<= port->regshift;
        return readw(port->membase + offset);
}

static void omap_serial_early_out(struct uart_port *port, int offset,
                                  int value)
{
        offset <<= port->regshift;
        writew(value, port->membase + offset);
}

static void omap_serial_early_putc(struct uart_port *port, int c)
{
        unsigned int status;

        for (;;) {
                status = omap_serial_early_in(port, UART_LSR);
                if ((status & BOTH_EMPTY) == BOTH_EMPTY)
                        break;
                cpu_relax();
        }
        omap_serial_early_out(port, UART_TX, c);
}

static void early_omap_serial_write(struct console *console, const char *s,
                                    unsigned int count)
{
        struct earlycon_device *device = console->data;
        struct uart_port *port = &device->port;

        uart_console_write(port, s, count, omap_serial_early_putc);
}

static int __init early_omap_serial_setup(struct earlycon_device *device,
                                          const char *options)
{
        struct uart_port *port = &device->port;

        if (!(device->port.membase || device->port.iobase))
                return -ENODEV;

        port->regshift = 2;
        device->con->write = early_omap_serial_write;
        return 0;
}

OF_EARLYCON_DECLARE(omapserial, "ti,omap2-uart", early_omap_serial_setup);
OF_EARLYCON_DECLARE(omapserial, "ti,omap3-uart", early_omap_serial_setup);
OF_EARLYCON_DECLARE(omapserial, "ti,omap4-uart", early_omap_serial_setup);
#endif /* CONFIG_SERIAL_EARLYCON */

static struct uart_omap_port *serial_omap_console_ports[OMAP_MAX_HSUART_PORTS];

static struct uart_driver serial_omap_reg;

static void serial_omap_console_putchar(struct uart_port *port, int ch)
{
        struct uart_omap_port *up = to_uart_omap_port(port);

        wait_for_xmitr(up);
        serial_out(up, UART_TX, ch);
}

static void
serial_omap_console_write(struct console *co, const char *s,
                unsigned int count)
{
        struct uart_omap_port *up = serial_omap_console_ports[co->index];
        unsigned long flags;
        unsigned int ier;
        int locked = 1;

        local_irq_save(flags);
        if (up->port.sysrq)
                locked = 0;
        else if (oops_in_progress)
                locked = spin_trylock(&up->port.lock);
        else
                spin_lock(&up->port.lock);

        /*
         * First save the IER then disable the interrupts
         */
        ier = serial_in(up, UART_IER);
        serial_out(up, UART_IER, 0);

        uart_console_write(&up->port, s, count, serial_omap_console_putchar);

        /*
         * Finally, wait for transmitter to become empty
         * and restore the IER
         */
        wait_for_xmitr(up);
        serial_out(up, UART_IER, ier);
        /*
         * The receive handling will happen properly because the
         * receive ready bit will still be set; it is not cleared
         * on read.  However, modem control will not, we must
         * call it if we have saved something in the saved flags
         * while processing with interrupts off.
         */
        if (up->msr_saved_flags)
                check_modem_status(up);

        if (locked)
                spin_unlock(&up->port.lock);
        local_irq_restore(flags);
}

static int __init
serial_omap_console_setup(struct console *co, char *options)
{
        struct uart_omap_port *up;
        int baud = 115200;
        int bits = 8;
        int parity = 'n';
        int flow = 'n';

        if (serial_omap_console_ports[co->index] == NULL)
                return -ENODEV;
        up = serial_omap_console_ports[co->index];

        if (options)
                uart_parse_options(options, &baud, &parity, &bits, &flow);

        return uart_set_options(&up->port, co, baud, parity, bits, flow);
}

static struct console serial_omap_console = {
        .name           = OMAP_SERIAL_NAME,
        .write          = serial_omap_console_write,
        .device         = uart_console_device,
        .setup          = serial_omap_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
        .data           = &serial_omap_reg,
};

static void serial_omap_add_console_port(struct uart_omap_port *up)
{
        serial_omap_console_ports[up->port.line] = up;
}

#define OMAP_CONSOLE    (&serial_omap_console)

#else

#define OMAP_CONSOLE    NULL

static inline void serial_omap_add_console_port(struct uart_omap_port *up)
{}

#endif

/* Enable or disable the rs485 support */
static int
serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485)
{
        struct uart_omap_port *up = to_uart_omap_port(port);
        unsigned int mode;
        int val;

        /* Disable interrupts from this port */
        mode = up->ier;
        up->ier = 0;
        serial_out(up, UART_IER, 0);

        /* Clamp the delays to [0, 100ms] */
        rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);
        rs485->delay_rts_after_send  = min(rs485->delay_rts_after_send, 100U);

        /* store new config */
        port->rs485 = *rs485;

        if (up->rts_gpiod) {
                /* enable / disable rts */
                val = (port->rs485.flags & SER_RS485_ENABLED) ?
                        SER_RS485_RTS_AFTER_SEND : SER_RS485_RTS_ON_SEND;
                val = (port->rs485.flags & val) ? 1 : 0;
                gpiod_set_value(up->rts_gpiod, val);
        }

        /* Enable interrupts */
        up->ier = mode;
        serial_out(up, UART_IER, up->ier);

        /* If RS-485 is disabled, make sure the THR interrupt is fired when
         * TX FIFO is below the trigger level.
         */
        if (!(port->rs485.flags & SER_RS485_ENABLED) &&
            (up->scr & OMAP_UART_SCR_TX_EMPTY)) {
                up->scr &= ~OMAP_UART_SCR_TX_EMPTY;
                serial_out(up, UART_OMAP_SCR, up->scr);
        }

        return 0;
}

static const struct uart_ops serial_omap_pops = {
        .tx_empty       = serial_omap_tx_empty,
        .set_mctrl      = serial_omap_set_mctrl,
        .get_mctrl      = serial_omap_get_mctrl,
        .stop_tx        = serial_omap_stop_tx,
        .start_tx       = serial_omap_start_tx,
        .throttle       = serial_omap_throttle,
        .unthrottle     = serial_omap_unthrottle,
        .stop_rx        = serial_omap_stop_rx,
        .enable_ms      = serial_omap_enable_ms,
        .break_ctl      = serial_omap_break_ctl,
        .startup        = serial_omap_startup,
        .shutdown       = serial_omap_shutdown,
        .set_termios    = serial_omap_set_termios,
        .pm             = serial_omap_pm,
        .type           = serial_omap_type,
        .release_port   = serial_omap_release_port,
        .request_port   = serial_omap_request_port,
        .config_port    = serial_omap_config_port,
        .verify_port    = serial_omap_verify_port,
#ifdef CONFIG_CONSOLE_POLL
        .poll_put_char  = serial_omap_poll_put_char,
        .poll_get_char  = serial_omap_poll_get_char,
#endif
};

static struct uart_driver serial_omap_reg = {
        .owner          = THIS_MODULE,
        .driver_name    = "OMAP-SERIAL",
        .dev_name       = OMAP_SERIAL_NAME,
        .nr             = OMAP_MAX_HSUART_PORTS,
        .cons           = OMAP_CONSOLE,
};

#ifdef CONFIG_PM_SLEEP
static int serial_omap_prepare(struct device *dev)
{
        struct uart_omap_port *up = dev_get_drvdata(dev);

        up->is_suspending = true;

        return 0;
}

static void serial_omap_complete(struct device *dev)
{
        struct uart_omap_port *up = dev_get_drvdata(dev);

        up->is_suspending = false;
}

static int serial_omap_suspend(struct device *dev)
{
        struct uart_omap_port *up = dev_get_drvdata(dev);

        uart_suspend_port(&serial_omap_reg, &up->port);
        flush_work(&up->qos_work);

        if (device_may_wakeup(dev))
                serial_omap_enable_wakeup(up, true);
        else
                serial_omap_enable_wakeup(up, false);

        return 0;
}

static int serial_omap_resume(struct device *dev)
{
        struct uart_omap_port *up = dev_get_drvdata(dev);

        if (device_may_wakeup(dev))
                serial_omap_enable_wakeup(up, false);

        uart_resume_port(&serial_omap_reg, &up->port);

        return 0;
}
#else
#define serial_omap_prepare NULL
#define serial_omap_complete NULL
#endif /* CONFIG_PM_SLEEP */

static void omap_serial_fill_features_erratas(struct uart_omap_port *up)
{
        u32 mvr, scheme;
        u16 revision, major, minor;

        mvr = readl(up->port.membase + (UART_OMAP_MVER << up->port.regshift));

        /* Check revision register scheme */
        scheme = mvr >> OMAP_UART_MVR_SCHEME_SHIFT;

        switch (scheme) {
        case 0: /* Legacy Scheme: OMAP2/3 */
                /* MINOR_REV[0:4], MAJOR_REV[4:7] */
                major = (mvr & OMAP_UART_LEGACY_MVR_MAJ_MASK) >>
                                        OMAP_UART_LEGACY_MVR_MAJ_SHIFT;
                minor = (mvr & OMAP_UART_LEGACY_MVR_MIN_MASK);
                break;
        case 1:
                /* New Scheme: OMAP4+ */
                /* MINOR_REV[0:5], MAJOR_REV[8:10] */
                major = (mvr & OMAP_UART_MVR_MAJ_MASK) >>
                                        OMAP_UART_MVR_MAJ_SHIFT;
                minor = (mvr & OMAP_UART_MVR_MIN_MASK);
                break;
        default:
                dev_warn(up->dev,
                        "Unknown %s revision, defaulting to highest\n",
                        up->name);
                /* highest possible revision */
                major = 0xff;
                minor = 0xff;
        }

        /* normalize revision for the driver */
        revision = UART_BUILD_REVISION(major, minor);

        switch (revision) {
        case OMAP_UART_REV_46:
                up->errata |= (UART_ERRATA_i202_MDR1_ACCESS |
                                UART_ERRATA_i291_DMA_FORCEIDLE);
                break;
        case OMAP_UART_REV_52:
                up->errata |= (UART_ERRATA_i202_MDR1_ACCESS |
                                UART_ERRATA_i291_DMA_FORCEIDLE);
                up->features |= OMAP_UART_WER_HAS_TX_WAKEUP;
                break;
        case OMAP_UART_REV_63:
                up->errata |= UART_ERRATA_i202_MDR1_ACCESS;
                up->features |= OMAP_UART_WER_HAS_TX_WAKEUP;
                break;
        default:
                break;
        }
}

static struct omap_uart_port_info *of_get_uart_port_info(struct device *dev)
{
        struct omap_uart_port_info *omap_up_info;

        omap_up_info = devm_kzalloc(dev, sizeof(*omap_up_info), GFP_KERNEL);
        if (!omap_up_info)
                return NULL; /* out of memory */

        of_property_read_u32(dev->of_node, "clock-frequency",
                                         &omap_up_info->uartclk);

        omap_up_info->flags = UPF_BOOT_AUTOCONF;

        return omap_up_info;
}

static int serial_omap_probe_rs485(struct uart_omap_port *up,
                                   struct device *dev)
{
        struct serial_rs485 *rs485conf = &up->port.rs485;
        struct device_node *np = dev->of_node;
        enum gpiod_flags gflags;
        int ret;

        rs485conf->flags = 0;
        up->rts_gpiod = NULL;

        if (!np)
                return 0;

        ret = uart_get_rs485_mode(&up->port);
        if (ret)
                return ret;

        if (of_property_read_bool(np, "rs485-rts-active-high")) {
                rs485conf->flags |= SER_RS485_RTS_ON_SEND;
                rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
        } else {
                rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
                rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
        }

        /* check for tx enable gpio */
        gflags = rs485conf->flags & SER_RS485_RTS_AFTER_SEND ?
                GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
        up->rts_gpiod = devm_gpiod_get_optional(dev, "rts", gflags);
        if (IS_ERR(up->rts_gpiod)) {
                ret = PTR_ERR(up->rts_gpiod);
                if (ret == -EPROBE_DEFER)
                        return ret;
                /*
                 * FIXME: the code historically ignored any other error than
                 * -EPROBE_DEFER and just went on without GPIO.
                 */
                up->rts_gpiod = NULL;
        } else {
                gpiod_set_consumer_name(up->rts_gpiod, "omap-serial");
        }

        return 0;
}

static int serial_omap_probe(struct platform_device *pdev)
{
        struct omap_uart_port_info *omap_up_info = dev_get_platdata(&pdev->dev);
        struct uart_omap_port *up;
        struct resource *mem;
        void __iomem *base;
        int uartirq = 0;
        int wakeirq = 0;
        int ret;

        /* The optional wakeirq may be specified in the board dts file */
        if (pdev->dev.of_node) {
                uartirq = irq_of_parse_and_map(pdev->dev.of_node, 0);
                if (!uartirq)
                        return -EPROBE_DEFER;
                wakeirq = irq_of_parse_and_map(pdev->dev.of_node, 1);
                omap_up_info = of_get_uart_port_info(&pdev->dev);
                pdev->dev.platform_data = omap_up_info;
        } else {
                uartirq = platform_get_irq(pdev, 0);
                if (uartirq < 0)
                        return -EPROBE_DEFER;
        }

        up = devm_kzalloc(&pdev->dev, sizeof(*up), GFP_KERNEL);
        if (!up)
                return -ENOMEM;

        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        base = devm_ioremap_resource(&pdev->dev, mem);
        if (IS_ERR(base))
                return PTR_ERR(base);

        up->dev = &pdev->dev;
        up->port.dev = &pdev->dev;
        up->port.type = PORT_OMAP;
        up->port.iotype = UPIO_MEM;
        up->port.irq = uartirq;
        up->port.regshift = 2;
        up->port.fifosize = 64;
        up->port.ops = &serial_omap_pops;
        up->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_OMAP_CONSOLE);

        if (pdev->dev.of_node)
                ret = of_alias_get_id(pdev->dev.of_node, "serial");
        else
                ret = pdev->id;

        if (ret < 0) {
                dev_err(&pdev->dev, "failed to get alias/pdev id, errno %d\n",
                        ret);
                goto err_port_line;
        }
        up->port.line = ret;

        if (up->port.line >= OMAP_MAX_HSUART_PORTS) {
                dev_err(&pdev->dev, "uart ID %d >  MAX %d.\n", up->port.line,
                        OMAP_MAX_HSUART_PORTS);
                ret = -ENXIO;
                goto err_port_line;
        }

        up->wakeirq = wakeirq;
        if (!up->wakeirq)
                dev_info(up->port.dev, "no wakeirq for uart%d\n",
                         up->port.line);

        ret = serial_omap_probe_rs485(up, &pdev->dev);
        if (ret < 0)
                goto err_rs485;

        sprintf(up->name, "OMAP UART%d", up->port.line);
        up->port.mapbase = mem->start;
        up->port.membase = base;
        up->port.flags = omap_up_info->flags;
        up->port.uartclk = omap_up_info->uartclk;
        up->port.rs485_config = serial_omap_config_rs485;
        if (!up->port.uartclk) {
                up->port.uartclk = DEFAULT_CLK_SPEED;
                dev_warn(&pdev->dev,
                         "No clock speed specified: using default: %d\n",
                         DEFAULT_CLK_SPEED);
        }

        up->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
        up->calc_latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
        cpu_latency_qos_add_request(&up->pm_qos_request, up->latency);
        INIT_WORK(&up->qos_work, serial_omap_uart_qos_work);

        platform_set_drvdata(pdev, up);
        if (omap_up_info->autosuspend_timeout == 0)
                omap_up_info->autosuspend_timeout = -1;

        device_init_wakeup(up->dev, true);

        pm_runtime_enable(&pdev->dev);

        pm_runtime_get_sync(&pdev->dev);

        omap_serial_fill_features_erratas(up);

        ui[up->port.line] = up;
        serial_omap_add_console_port(up);

        ret = uart_add_one_port(&serial_omap_reg, &up->port);
        if (ret != 0)
                goto err_add_port;

        return 0;

err_add_port:
        pm_runtime_put_sync(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
        cpu_latency_qos_remove_request(&up->pm_qos_request);
        device_init_wakeup(up->dev, false);
err_rs485:
err_port_line:
        return ret;
}

static int serial_omap_remove(struct platform_device *dev)
{
        struct uart_omap_port *up = platform_get_drvdata(dev);

        pm_runtime_get_sync(up->dev);

        uart_remove_one_port(&serial_omap_reg, &up->port);

        pm_runtime_put_sync(up->dev);
        pm_runtime_disable(up->dev);
        cpu_latency_qos_remove_request(&up->pm_qos_request);
        device_init_wakeup(&dev->dev, false);

        return 0;
}

/*
 * Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460)
 * The access to uart register after MDR1 Access
 * causes UART to corrupt data.
 *
 * Need a delay =
 * 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS)
 * give 10 times as much
 */
static void serial_omap_mdr1_errataset(struct uart_omap_port *up, u8 mdr1)
{
        u8 timeout = 255;

        serial_out(up, UART_OMAP_MDR1, mdr1);
        udelay(2);
        serial_out(up, UART_FCR, up->fcr | UART_FCR_CLEAR_XMIT |
                        UART_FCR_CLEAR_RCVR);
        /*
         * Wait for FIFO to empty: when empty, RX_FIFO_E bit is 0 and
         * TX_FIFO_E bit is 1.
         */
        while (UART_LSR_THRE != (serial_in(up, UART_LSR) &
                                (UART_LSR_THRE | UART_LSR_DR))) {
                timeout--;
                if (!timeout) {
                        /* Should *never* happen. we warn and carry on */
                        dev_crit(up->dev, "Errata i202: timedout %x\n",
                                                serial_in(up, UART_LSR));
                        break;
                }
                udelay(1);
        }
}

#ifdef CONFIG_PM
static void serial_omap_restore_context(struct uart_omap_port *up)
{
        if (up->errata & UART_ERRATA_i202_MDR1_ACCESS)
                serial_omap_mdr1_errataset(up, UART_OMAP_MDR1_DISABLE);
        else
                serial_out(up, UART_OMAP_MDR1, UART_OMAP_MDR1_DISABLE);

        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); /* Config B mode */
        serial_out(up, UART_EFR, UART_EFR_ECB);
        serial_out(up, UART_LCR, 0x0); /* Operational mode */
        serial_out(up, UART_IER, 0x0);
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); /* Config B mode */
        serial_out(up, UART_DLL, up->dll);
        serial_out(up, UART_DLM, up->dlh);
        serial_out(up, UART_LCR, 0x0); /* Operational mode */
        serial_out(up, UART_IER, up->ier);
        serial_out(up, UART_FCR, up->fcr);
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
        serial_out(up, UART_MCR, up->mcr);
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); /* Config B mode */
        serial_out(up, UART_OMAP_SCR, up->scr);
        serial_out(up, UART_EFR, up->efr);
        serial_out(up, UART_LCR, up->lcr);
        if (up->errata & UART_ERRATA_i202_MDR1_ACCESS)
                serial_omap_mdr1_errataset(up, up->mdr1);
        else
                serial_out(up, UART_OMAP_MDR1, up->mdr1);
        serial_out(up, UART_OMAP_WER, up->wer);
}

static int serial_omap_runtime_suspend(struct device *dev)
{
        struct uart_omap_port *up = dev_get_drvdata(dev);

        if (!up)
                return -EINVAL;

        /*
        * When using 'no_console_suspend', the console UART must not be
        * suspended. Since driver suspend is managed by runtime suspend,
        * preventing runtime suspend (by returning error) will keep device
        * active during suspend.
        */
        if (up->is_suspending && !console_suspend_enabled &&
            uart_console(&up->port))
                return -EBUSY;

        up->context_loss_cnt = serial_omap_get_context_loss_count(up);

        serial_omap_enable_wakeup(up, true);

        up->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
        schedule_work(&up->qos_work);

        return 0;
}

static int serial_omap_runtime_resume(struct device *dev)
{
        struct uart_omap_port *up = dev_get_drvdata(dev);

        int loss_cnt = serial_omap_get_context_loss_count(up);

        serial_omap_enable_wakeup(up, false);

        if (loss_cnt < 0) {
                dev_dbg(dev, "serial_omap_get_context_loss_count failed : %d\n",
                        loss_cnt);
                serial_omap_restore_context(up);
        } else if (up->context_loss_cnt != loss_cnt) {
                serial_omap_restore_context(up);
        }
        up->latency = up->calc_latency;
        schedule_work(&up->qos_work);

        return 0;
}
#endif

static const struct dev_pm_ops serial_omap_dev_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(serial_omap_suspend, serial_omap_resume)
        SET_RUNTIME_PM_OPS(serial_omap_runtime_suspend,
                                serial_omap_runtime_resume, NULL)
        .prepare        = serial_omap_prepare,
        .complete       = serial_omap_complete,
};

#if defined(CONFIG_OF)
static const struct of_device_id omap_serial_of_match[] = {
        { .compatible = "ti,omap2-uart" },
        { .compatible = "ti,omap3-uart" },
        { .compatible = "ti,omap4-uart" },
        {},
};
MODULE_DEVICE_TABLE(of, omap_serial_of_match);
#endif

static struct platform_driver serial_omap_driver = {
        .probe          = serial_omap_probe,
        .remove         = serial_omap_remove,
        .driver         = {
                .name   = OMAP_SERIAL_DRIVER_NAME,
                .pm     = &serial_omap_dev_pm_ops,
                .of_match_table = of_match_ptr(omap_serial_of_match),
        },
};

static int __init serial_omap_init(void)
{
        int ret;

        ret = uart_register_driver(&serial_omap_reg);
        if (ret != 0)
                return ret;
        ret = platform_driver_register(&serial_omap_driver);
        if (ret != 0)
                uart_unregister_driver(&serial_omap_reg);
        return ret;
}

static void __exit serial_omap_exit(void)
{
        platform_driver_unregister(&serial_omap_driver);
        uart_unregister_driver(&serial_omap_reg);
}

module_init(serial_omap_init);
module_exit(serial_omap_exit);

MODULE_DESCRIPTION("OMAP High Speed UART driver");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Texas Instruments Inc");