// SPDX-License-Identifier: GPL-2.0
/*
 * Derived from many drivers using generic_serial interface.
 *
 * Copyright (C) 2008 Maxime Bizon <mbizon@freebox.fr>
 *
 *  Serial driver for BCM63xx integrated UART.
 *
 * Hardware flow control was _not_ tested since I only have RX/TX on
 * my board.
 */

#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/console.h>
#include <linux/clk.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/sysrq.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/serial_bcm63xx.h>
#include <linux/io.h>
#include <linux/of.h>

#define BCM63XX_NR_UARTS        2

static struct uart_port ports[BCM63XX_NR_UARTS];

/*
 * rx interrupt mask / stat
 *
 * mask:
 *  - rx fifo full
 *  - rx fifo above threshold
 *  - rx fifo not empty for too long
 */
#define UART_RX_INT_MASK        (UART_IR_MASK(UART_IR_RXOVER) |         \
                                UART_IR_MASK(UART_IR_RXTHRESH) |        \
                                UART_IR_MASK(UART_IR_RXTIMEOUT))

#define UART_RX_INT_STAT        (UART_IR_STAT(UART_IR_RXOVER) |         \
                                UART_IR_STAT(UART_IR_RXTHRESH) |        \
                                UART_IR_STAT(UART_IR_RXTIMEOUT))

/*
 * tx interrupt mask / stat
 *
 * mask:
 * - tx fifo empty
 * - tx fifo below threshold
 */
#define UART_TX_INT_MASK        (UART_IR_MASK(UART_IR_TXEMPTY) |        \
                                UART_IR_MASK(UART_IR_TXTRESH))

#define UART_TX_INT_STAT        (UART_IR_STAT(UART_IR_TXEMPTY) |        \
                                UART_IR_STAT(UART_IR_TXTRESH))

/*
 * external input interrupt
 *
 * mask: any edge on CTS, DCD
 */
#define UART_EXTINP_INT_MASK    (UART_EXTINP_IRMASK(UART_EXTINP_IR_CTS) | \
                                 UART_EXTINP_IRMASK(UART_EXTINP_IR_DCD))

/*
 * handy uart register accessor
 */
static inline unsigned int bcm_uart_readl(struct uart_port *port,
                                         unsigned int offset)
{
        return __raw_readl(port->membase + offset);
}

static inline void bcm_uart_writel(struct uart_port *port,
                                  unsigned int value, unsigned int offset)
{
        __raw_writel(value, port->membase + offset);
}

/*
 * serial core request to check if uart tx fifo is empty
 */
static unsigned int bcm_uart_tx_empty(struct uart_port *port)
{
        unsigned int val;

        val = bcm_uart_readl(port, UART_IR_REG);
        return (val & UART_IR_STAT(UART_IR_TXEMPTY)) ? 1 : 0;
}

/*
 * serial core request to set RTS and DTR pin state and loopback mode
 */
static void bcm_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        unsigned int val;

        val = bcm_uart_readl(port, UART_MCTL_REG);
        val &= ~(UART_MCTL_DTR_MASK | UART_MCTL_RTS_MASK);
        /* invert of written value is reflected on the pin */
        if (!(mctrl & TIOCM_DTR))
                val |= UART_MCTL_DTR_MASK;
        if (!(mctrl & TIOCM_RTS))
                val |= UART_MCTL_RTS_MASK;
        bcm_uart_writel(port, val, UART_MCTL_REG);

        val = bcm_uart_readl(port, UART_CTL_REG);
        if (mctrl & TIOCM_LOOP)
                val |= UART_CTL_LOOPBACK_MASK;
        else
                val &= ~UART_CTL_LOOPBACK_MASK;
        bcm_uart_writel(port, val, UART_CTL_REG);
}

/*
 * serial core request to return RI, CTS, DCD and DSR pin state
 */
static unsigned int bcm_uart_get_mctrl(struct uart_port *port)
{
        unsigned int val, mctrl;

        mctrl = 0;
        val = bcm_uart_readl(port, UART_EXTINP_REG);
        if (val & UART_EXTINP_RI_MASK)
                mctrl |= TIOCM_RI;
        if (val & UART_EXTINP_CTS_MASK)
                mctrl |= TIOCM_CTS;
        if (val & UART_EXTINP_DCD_MASK)
                mctrl |= TIOCM_CD;
        if (val & UART_EXTINP_DSR_MASK)
                mctrl |= TIOCM_DSR;
        return mctrl;
}

/*
 * serial core request to disable tx ASAP (used for flow control)
 */
static void bcm_uart_stop_tx(struct uart_port *port)
{
        unsigned int val;

        val = bcm_uart_readl(port, UART_CTL_REG);
        val &= ~(UART_CTL_TXEN_MASK);
        bcm_uart_writel(port, val, UART_CTL_REG);

        val = bcm_uart_readl(port, UART_IR_REG);
        val &= ~UART_TX_INT_MASK;
        bcm_uart_writel(port, val, UART_IR_REG);
}

/*
 * serial core request to (re)enable tx
 */
static void bcm_uart_start_tx(struct uart_port *port)
{
        unsigned int val;

        val = bcm_uart_readl(port, UART_IR_REG);
        val |= UART_TX_INT_MASK;
        bcm_uart_writel(port, val, UART_IR_REG);

        val = bcm_uart_readl(port, UART_CTL_REG);
        val |= UART_CTL_TXEN_MASK;
        bcm_uart_writel(port, val, UART_CTL_REG);
}

/*
 * serial core request to stop rx, called before port shutdown
 */
static void bcm_uart_stop_rx(struct uart_port *port)
{
        unsigned int val;

        val = bcm_uart_readl(port, UART_IR_REG);
        val &= ~UART_RX_INT_MASK;
        bcm_uart_writel(port, val, UART_IR_REG);
}

/*
 * serial core request to enable modem status interrupt reporting
 */
static void bcm_uart_enable_ms(struct uart_port *port)
{
        unsigned int val;

        val = bcm_uart_readl(port, UART_IR_REG);
        val |= UART_IR_MASK(UART_IR_EXTIP);
        bcm_uart_writel(port, val, UART_IR_REG);
}

/*
 * serial core request to start/stop emitting break char
 */
static void bcm_uart_break_ctl(struct uart_port *port, int ctl)
{
        unsigned long flags;
        unsigned int val;

        spin_lock_irqsave(&port->lock, flags);

        val = bcm_uart_readl(port, UART_CTL_REG);
        if (ctl)
                val |= UART_CTL_XMITBRK_MASK;
        else
                val &= ~UART_CTL_XMITBRK_MASK;
        bcm_uart_writel(port, val, UART_CTL_REG);

        spin_unlock_irqrestore(&port->lock, flags);
}

/*
 * return port type in string format
 */
static const char *bcm_uart_type(struct uart_port *port)
{
        return (port->type == PORT_BCM63XX) ? "bcm63xx_uart" : NULL;
}

/*
 * read all chars in rx fifo and send them to core
 */
static void bcm_uart_do_rx(struct uart_port *port)
{
        struct tty_port *tty_port = &port->state->port;
        unsigned int max_count;

        /* limit number of char read in interrupt, should not be
         * higher than fifo size anyway since we're much faster than
         * serial port */
        max_count = 32;
        do {
                unsigned int iestat, c, cstat;
                char flag;

                /* get overrun/fifo empty information from ier
                 * register */
                iestat = bcm_uart_readl(port, UART_IR_REG);

                if (unlikely(iestat & UART_IR_STAT(UART_IR_RXOVER))) {
                        unsigned int val;

                        /* fifo reset is required to clear
                         * interrupt */
                        val = bcm_uart_readl(port, UART_CTL_REG);
                        val |= UART_CTL_RSTRXFIFO_MASK;
                        bcm_uart_writel(port, val, UART_CTL_REG);

                        port->icount.overrun++;
                        tty_insert_flip_char(tty_port, 0, TTY_OVERRUN);
                }

                if (!(iestat & UART_IR_STAT(UART_IR_RXNOTEMPTY)))
                        break;

                cstat = c = bcm_uart_readl(port, UART_FIFO_REG);
                port->icount.rx++;
                flag = TTY_NORMAL;
                c &= 0xff;

                if (unlikely((cstat & UART_FIFO_ANYERR_MASK))) {
                        /* do stats first */
                        if (cstat & UART_FIFO_BRKDET_MASK) {
                                port->icount.brk++;
                                if (uart_handle_break(port))
                                        continue;
                        }

                        if (cstat & UART_FIFO_PARERR_MASK)
                                port->icount.parity++;
                        if (cstat & UART_FIFO_FRAMEERR_MASK)
                                port->icount.frame++;

                        /* update flag wrt read_status_mask */
                        cstat &= port->read_status_mask;
                        if (cstat & UART_FIFO_BRKDET_MASK)
                                flag = TTY_BREAK;
                        if (cstat & UART_FIFO_FRAMEERR_MASK)
                                flag = TTY_FRAME;
                        if (cstat & UART_FIFO_PARERR_MASK)
                                flag = TTY_PARITY;
                }

                if (uart_handle_sysrq_char(port, c))
                        continue;


                if ((cstat & port->ignore_status_mask) == 0)
                        tty_insert_flip_char(tty_port, c, flag);

        } while (--max_count);

        tty_flip_buffer_push(tty_port);
}

/*
 * fill tx fifo with chars to send, stop when fifo is about to be full
 * or when all chars have been sent.
 */
static void bcm_uart_do_tx(struct uart_port *port)
{
        struct circ_buf *xmit;
        unsigned int val, max_count;

        if (port->x_char) {
                bcm_uart_writel(port, port->x_char, UART_FIFO_REG);
                port->icount.tx++;
                port->x_char = 0;
                return;
        }

        if (uart_tx_stopped(port)) {
                bcm_uart_stop_tx(port);
                return;
        }

        xmit = &port->state->xmit;
        if (uart_circ_empty(xmit))
                goto txq_empty;

        val = bcm_uart_readl(port, UART_MCTL_REG);
        val = (val & UART_MCTL_TXFIFOFILL_MASK) >> UART_MCTL_TXFIFOFILL_SHIFT;
        max_count = port->fifosize - val;

        while (max_count--) {
                unsigned int c;

                c = xmit->buf[xmit->tail];
                bcm_uart_writel(port, c, UART_FIFO_REG);
                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                port->icount.tx++;
                if (uart_circ_empty(xmit))
                        break;
        }

        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
                uart_write_wakeup(port);

        if (uart_circ_empty(xmit))
                goto txq_empty;
        return;

txq_empty:
        /* nothing to send, disable transmit interrupt */
        val = bcm_uart_readl(port, UART_IR_REG);
        val &= ~UART_TX_INT_MASK;
        bcm_uart_writel(port, val, UART_IR_REG);
        return;
}

/*
 * process uart interrupt
 */
static irqreturn_t bcm_uart_interrupt(int irq, void *dev_id)
{
        struct uart_port *port;
        unsigned int irqstat;

        port = dev_id;
        spin_lock(&port->lock);

        irqstat = bcm_uart_readl(port, UART_IR_REG);
        if (irqstat & UART_RX_INT_STAT)
                bcm_uart_do_rx(port);

        if (irqstat & UART_TX_INT_STAT)
                bcm_uart_do_tx(port);

        if (irqstat & UART_IR_MASK(UART_IR_EXTIP)) {
                unsigned int estat;

                estat = bcm_uart_readl(port, UART_EXTINP_REG);
                if (estat & UART_EXTINP_IRSTAT(UART_EXTINP_IR_CTS))
                        uart_handle_cts_change(port,
                                               estat & UART_EXTINP_CTS_MASK);
                if (estat & UART_EXTINP_IRSTAT(UART_EXTINP_IR_DCD))
                        uart_handle_dcd_change(port,
                                               estat & UART_EXTINP_DCD_MASK);
        }

        spin_unlock(&port->lock);
        return IRQ_HANDLED;
}

/*
 * enable rx & tx operation on uart
 */
static void bcm_uart_enable(struct uart_port *port)
{
        unsigned int val;

        val = bcm_uart_readl(port, UART_CTL_REG);
        val |= (UART_CTL_BRGEN_MASK | UART_CTL_TXEN_MASK | UART_CTL_RXEN_MASK);
        bcm_uart_writel(port, val, UART_CTL_REG);
}

/*
 * disable rx & tx operation on uart
 */
static void bcm_uart_disable(struct uart_port *port)
{
        unsigned int val;

        val = bcm_uart_readl(port, UART_CTL_REG);
        val &= ~(UART_CTL_BRGEN_MASK | UART_CTL_TXEN_MASK |
                 UART_CTL_RXEN_MASK);
        bcm_uart_writel(port, val, UART_CTL_REG);
}

/*
 * clear all unread data in rx fifo and unsent data in tx fifo
 */
static void bcm_uart_flush(struct uart_port *port)
{
        unsigned int val;

        /* empty rx and tx fifo */
        val = bcm_uart_readl(port, UART_CTL_REG);
        val |= UART_CTL_RSTRXFIFO_MASK | UART_CTL_RSTTXFIFO_MASK;
        bcm_uart_writel(port, val, UART_CTL_REG);

        /* read any pending char to make sure all irq status are
         * cleared */
        (void)bcm_uart_readl(port, UART_FIFO_REG);
}

/*
 * serial core request to initialize uart and start rx operation
 */
static int bcm_uart_startup(struct uart_port *port)
{
        unsigned int val;
        int ret;

        /* mask all irq and flush port */
        bcm_uart_disable(port);
        bcm_uart_writel(port, 0, UART_IR_REG);
        bcm_uart_flush(port);

        /* clear any pending external input interrupt */
        (void)bcm_uart_readl(port, UART_EXTINP_REG);

        /* set rx/tx fifo thresh to fifo half size */
        val = bcm_uart_readl(port, UART_MCTL_REG);
        val &= ~(UART_MCTL_RXFIFOTHRESH_MASK | UART_MCTL_TXFIFOTHRESH_MASK);
        val |= (port->fifosize / 2) << UART_MCTL_RXFIFOTHRESH_SHIFT;
        val |= (port->fifosize / 2) << UART_MCTL_TXFIFOTHRESH_SHIFT;
        bcm_uart_writel(port, val, UART_MCTL_REG);

        /* set rx fifo timeout to 1 char time */
        val = bcm_uart_readl(port, UART_CTL_REG);
        val &= ~UART_CTL_RXTMOUTCNT_MASK;
        val |= 1 << UART_CTL_RXTMOUTCNT_SHIFT;
        bcm_uart_writel(port, val, UART_CTL_REG);

        /* report any edge on dcd and cts */
        val = UART_EXTINP_INT_MASK;
        val |= UART_EXTINP_DCD_NOSENSE_MASK;
        val |= UART_EXTINP_CTS_NOSENSE_MASK;
        bcm_uart_writel(port, val, UART_EXTINP_REG);

        /* register irq and enable rx interrupts */
        ret = request_irq(port->irq, bcm_uart_interrupt, 0,
                          dev_name(port->dev), port);
        if (ret)
                return ret;
        bcm_uart_writel(port, UART_RX_INT_MASK, UART_IR_REG);
        bcm_uart_enable(port);
        return 0;
}

/*
 * serial core request to flush & disable uart
 */
static void bcm_uart_shutdown(struct uart_port *port)
{
        unsigned long flags;

        spin_lock_irqsave(&port->lock, flags);
        bcm_uart_writel(port, 0, UART_IR_REG);
        spin_unlock_irqrestore(&port->lock, flags);

        bcm_uart_disable(port);
        bcm_uart_flush(port);
        free_irq(port->irq, port);
}

/*
 * serial core request to change current uart setting
 */
static void bcm_uart_set_termios(struct uart_port *port,
                                 struct ktermios *new,
                                 struct ktermios *old)
{
        unsigned int ctl, baud, quot, ier;
        unsigned long flags;
        int tries;

        spin_lock_irqsave(&port->lock, flags);

        /* Drain the hot tub fully before we power it off for the winter. */
        for (tries = 3; !bcm_uart_tx_empty(port) && tries; tries--)
                mdelay(10);

        /* disable uart while changing speed */
        bcm_uart_disable(port);
        bcm_uart_flush(port);

        /* update Control register */
        ctl = bcm_uart_readl(port, UART_CTL_REG);
        ctl &= ~UART_CTL_BITSPERSYM_MASK;

        switch (new->c_cflag & CSIZE) {
        case CS5:
                ctl |= (0 << UART_CTL_BITSPERSYM_SHIFT);
                break;
        case CS6:
                ctl |= (1 << UART_CTL_BITSPERSYM_SHIFT);
                break;
        case CS7:
                ctl |= (2 << UART_CTL_BITSPERSYM_SHIFT);
                break;
        default:
                ctl |= (3 << UART_CTL_BITSPERSYM_SHIFT);
                break;
        }

        ctl &= ~UART_CTL_STOPBITS_MASK;
        if (new->c_cflag & CSTOPB)
                ctl |= UART_CTL_STOPBITS_2;
        else
                ctl |= UART_CTL_STOPBITS_1;

        ctl &= ~(UART_CTL_RXPAREN_MASK | UART_CTL_TXPAREN_MASK);
        if (new->c_cflag & PARENB)
                ctl |= (UART_CTL_RXPAREN_MASK | UART_CTL_TXPAREN_MASK);
        ctl &= ~(UART_CTL_RXPAREVEN_MASK | UART_CTL_TXPAREVEN_MASK);
        if (new->c_cflag & PARODD)
                ctl |= (UART_CTL_RXPAREVEN_MASK | UART_CTL_TXPAREVEN_MASK);
        bcm_uart_writel(port, ctl, UART_CTL_REG);

        /* update Baudword register */
        baud = uart_get_baud_rate(port, new, old, 0, port->uartclk / 16);
        quot = uart_get_divisor(port, baud) - 1;
        bcm_uart_writel(port, quot, UART_BAUD_REG);

        /* update Interrupt register */
        ier = bcm_uart_readl(port, UART_IR_REG);

        ier &= ~UART_IR_MASK(UART_IR_EXTIP);
        if (UART_ENABLE_MS(port, new->c_cflag))
                ier |= UART_IR_MASK(UART_IR_EXTIP);

        bcm_uart_writel(port, ier, UART_IR_REG);

        /* update read/ignore mask */
        port->read_status_mask = UART_FIFO_VALID_MASK;
        if (new->c_iflag & INPCK) {
                port->read_status_mask |= UART_FIFO_FRAMEERR_MASK;
                port->read_status_mask |= UART_FIFO_PARERR_MASK;
        }
        if (new->c_iflag & (IGNBRK | BRKINT))
                port->read_status_mask |= UART_FIFO_BRKDET_MASK;

        port->ignore_status_mask = 0;
        if (new->c_iflag & IGNPAR)
                port->ignore_status_mask |= UART_FIFO_PARERR_MASK;
        if (new->c_iflag & IGNBRK)
                port->ignore_status_mask |= UART_FIFO_BRKDET_MASK;
        if (!(new->c_cflag & CREAD))
                port->ignore_status_mask |= UART_FIFO_VALID_MASK;

        uart_update_timeout(port, new->c_cflag, baud);
        bcm_uart_enable(port);
        spin_unlock_irqrestore(&port->lock, flags);
}

/*
 * serial core request to claim uart iomem
 */
static int bcm_uart_request_port(struct uart_port *port)
{
        /* UARTs always present */
        return 0;
}

/*
 * serial core request to release uart iomem
 */
static void bcm_uart_release_port(struct uart_port *port)
{
        /* Nothing to release ... */
}

/*
 * serial core request to do any port required autoconfiguration
 */
static void bcm_uart_config_port(struct uart_port *port, int flags)
{
        if (flags & UART_CONFIG_TYPE) {
                if (bcm_uart_request_port(port))
                        return;
                port->type = PORT_BCM63XX;
        }
}

/*
 * serial core request to check that port information in serinfo are
 * suitable
 */
static int bcm_uart_verify_port(struct uart_port *port,
                                struct serial_struct *serinfo)
{
        if (port->type != PORT_BCM63XX)
                return -EINVAL;
        if (port->irq != serinfo->irq)
                return -EINVAL;
        if (port->iotype != serinfo->io_type)
                return -EINVAL;
        if (port->mapbase != (unsigned long)serinfo->iomem_base)
                return -EINVAL;
        return 0;
}

/* serial core callbacks */
static const struct uart_ops bcm_uart_ops = {
        .tx_empty       = bcm_uart_tx_empty,
        .get_mctrl      = bcm_uart_get_mctrl,
        .set_mctrl      = bcm_uart_set_mctrl,
        .start_tx       = bcm_uart_start_tx,
        .stop_tx        = bcm_uart_stop_tx,
        .stop_rx        = bcm_uart_stop_rx,
        .enable_ms      = bcm_uart_enable_ms,
        .break_ctl      = bcm_uart_break_ctl,
        .startup        = bcm_uart_startup,
        .shutdown       = bcm_uart_shutdown,
        .set_termios    = bcm_uart_set_termios,
        .type           = bcm_uart_type,
        .release_port   = bcm_uart_release_port,
        .request_port   = bcm_uart_request_port,
        .config_port    = bcm_uart_config_port,
        .verify_port    = bcm_uart_verify_port,
};



#ifdef CONFIG_SERIAL_BCM63XX_CONSOLE
static void wait_for_xmitr(struct uart_port *port)
{
        unsigned int tmout;

        /* Wait up to 10ms for the character(s) to be sent. */
        tmout = 10000;
        while (--tmout) {
                unsigned int val;

                val = bcm_uart_readl(port, UART_IR_REG);
                if (val & UART_IR_STAT(UART_IR_TXEMPTY))
                        break;
                udelay(1);
        }

        /* Wait up to 1s for flow control if necessary */
        if (port->flags & UPF_CONS_FLOW) {
                tmout = 1000000;
                while (--tmout) {
                        unsigned int val;

                        val = bcm_uart_readl(port, UART_EXTINP_REG);
                        if (val & UART_EXTINP_CTS_MASK)
                                break;
                        udelay(1);
                }
        }
}

/*
 * output given char
 */
static void bcm_console_putchar(struct uart_port *port, int ch)
{
        wait_for_xmitr(port);
        bcm_uart_writel(port, ch, UART_FIFO_REG);
}

/*
 * console core request to output given string
 */
static void bcm_console_write(struct console *co, const char *s,
                              unsigned int count)
{
        struct uart_port *port;
        unsigned long flags;
        int locked;

        port = &ports[co->index];

        local_irq_save(flags);
        if (port->sysrq) {
                /* bcm_uart_interrupt() already took the lock */
                locked = 0;
        } else if (oops_in_progress) {
                locked = spin_trylock(&port->lock);
        } else {
                spin_lock(&port->lock);
                locked = 1;
        }

        /* call helper to deal with \r\n */
        uart_console_write(port, s, count, bcm_console_putchar);

        /* and wait for char to be transmitted */
        wait_for_xmitr(port);

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

/*
 * console core request to setup given console, find matching uart
 * port and setup it.
 */
static int bcm_console_setup(struct console *co, char *options)
{
        struct uart_port *port;
        int baud = 9600;
        int bits = 8;
        int parity = 'n';
        int flow = 'n';

        if (co->index < 0 || co->index >= BCM63XX_NR_UARTS)
                return -EINVAL;
        port = &ports[co->index];
        if (!port->membase)
                return -ENODEV;
        if (options)
                uart_parse_options(options, &baud, &parity, &bits, &flow);

        return uart_set_options(port, co, baud, parity, bits, flow);
}

static struct uart_driver bcm_uart_driver;

static struct console bcm63xx_console = {
        .name           = "ttyS",
        .write          = bcm_console_write,
        .device         = uart_console_device,
        .setup          = bcm_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
        .data           = &bcm_uart_driver,
};

static int __init bcm63xx_console_init(void)
{
        register_console(&bcm63xx_console);
        return 0;
}

console_initcall(bcm63xx_console_init);

static void bcm_early_write(struct console *con, const char *s, unsigned n)
{
        struct earlycon_device *dev = con->data;

        uart_console_write(&dev->port, s, n, bcm_console_putchar);
        wait_for_xmitr(&dev->port);
}

static int __init bcm_early_console_setup(struct earlycon_device *device,
                                          const char *opt)
{
        if (!device->port.membase)
                return -ENODEV;

        device->con->write = bcm_early_write;
        return 0;
}

OF_EARLYCON_DECLARE(bcm63xx_uart, "brcm,bcm6345-uart", bcm_early_console_setup);

#define BCM63XX_CONSOLE (&bcm63xx_console)
#else
#define BCM63XX_CONSOLE NULL
#endif /* CONFIG_SERIAL_BCM63XX_CONSOLE */

static struct uart_driver bcm_uart_driver = {
        .owner          = THIS_MODULE,
        .driver_name    = "bcm63xx_uart",
        .dev_name       = "ttyS",
        .major          = TTY_MAJOR,
        .minor          = 64,
        .nr             = BCM63XX_NR_UARTS,
        .cons           = BCM63XX_CONSOLE,
};

/*
 * platform driver probe/remove callback
 */
static int bcm_uart_probe(struct platform_device *pdev)
{
        struct resource *res_mem, *res_irq;
        struct uart_port *port;
        struct clk *clk;
        int ret;

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

                if (pdev->id < 0)
                        pdev->id = of_alias_get_id(pdev->dev.of_node, "uart");
        }

        if (pdev->id < 0 || pdev->id >= BCM63XX_NR_UARTS)
                return -EINVAL;

        port = &ports[pdev->id];
        if (port->membase)
                return -EBUSY;
        memset(port, 0, sizeof(*port));

        res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res_mem)
                return -ENODEV;

        port->mapbase = res_mem->start;
        port->membase = devm_ioremap_resource(&pdev->dev, res_mem);
        if (IS_ERR(port->membase))
                return PTR_ERR(port->membase);

        res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
        if (!res_irq)
                return -ENODEV;

        clk = clk_get(&pdev->dev, "refclk");
        if (IS_ERR(clk) && pdev->dev.of_node)
                clk = of_clk_get(pdev->dev.of_node, 0);

        if (IS_ERR(clk))
                return -ENODEV;

        port->iotype = UPIO_MEM;
        port->irq = res_irq->start;
        port->ops = &bcm_uart_ops;
        port->flags = UPF_BOOT_AUTOCONF;
        port->dev = &pdev->dev;
        port->fifosize = 16;
        port->uartclk = clk_get_rate(clk) / 2;
        port->line = pdev->id;
        port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_BCM63XX_CONSOLE);
        clk_put(clk);

        ret = uart_add_one_port(&bcm_uart_driver, port);
        if (ret) {
                ports[pdev->id].membase = NULL;
                return ret;
        }
        platform_set_drvdata(pdev, port);
        return 0;
}

static int bcm_uart_remove(struct platform_device *pdev)
{
        struct uart_port *port;

        port = platform_get_drvdata(pdev);
        uart_remove_one_port(&bcm_uart_driver, port);
        /* mark port as free */
        ports[pdev->id].membase = NULL;
        return 0;
}

static const struct of_device_id bcm63xx_of_match[] = {
        { .compatible = "brcm,bcm6345-uart" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, bcm63xx_of_match);

/*
 * platform driver stuff
 */
static struct platform_driver bcm_uart_platform_driver = {
        .probe  = bcm_uart_probe,
        .remove = bcm_uart_remove,
        .driver = {
                .name  = "bcm63xx_uart",
                .of_match_table = bcm63xx_of_match,
        },
};

static int __init bcm_uart_init(void)
{
        int ret;

        ret = uart_register_driver(&bcm_uart_driver);
        if (ret)
                return ret;

        ret = platform_driver_register(&bcm_uart_platform_driver);
        if (ret)
                uart_unregister_driver(&bcm_uart_driver);

        return ret;
}

static void __exit bcm_uart_exit(void)
{
        platform_driver_unregister(&bcm_uart_platform_driver);
        uart_unregister_driver(&bcm_uart_driver);
}

module_init(bcm_uart_init);
module_exit(bcm_uart_exit);

MODULE_AUTHOR("Maxime Bizon <mbizon@freebox.fr>");
MODULE_DESCRIPTION("Broadcom 63xx integrated uart driver");
MODULE_LICENSE("GPL");