// SPDX-License-Identifier: GPL-2.0
/*
 * Driver core for Samsung SoC onboard UARTs.
 *
 * Ben Dooks, Copyright (c) 2003-2008 Simtec Electronics
 *      http://armlinux.simtec.co.uk/
 */

/* Note on 2410 error handling
 *
 * The s3c2410 manual has a love/hate affair with the contents of the
 * UERSTAT register in the UART blocks, and keeps marking some of the
 * error bits as reserved. Having checked with the s3c2410x01,
 * it copes with BREAKs properly, so I am happy to ignore the RESERVED
 * feature from the latter versions of the manual.
 *
 * If it becomes aparrent that latter versions of the 2410 remove these
 * bits, then action will have to be taken to differentiate the versions
 * and change the policy on BREAK
 *
 * BJD, 04-Nov-2004
 */

#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/init.h>
#include <linux/sysrq.h>
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/serial_s3c.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/cpufreq.h>
#include <linux/of.h>
#include <asm/irq.h>

/* UART name and device definitions */

#define S3C24XX_SERIAL_NAME     "ttySAC"
#define S3C24XX_SERIAL_MAJOR    204
#define S3C24XX_SERIAL_MINOR    64

#define S3C24XX_TX_PIO                  1
#define S3C24XX_TX_DMA                  2
#define S3C24XX_RX_PIO                  1
#define S3C24XX_RX_DMA                  2

/* flag to ignore all characters coming in */
#define RXSTAT_DUMMY_READ (0x10000000)

enum s3c24xx_port_type {
        TYPE_S3C24XX,
        TYPE_S3C6400,
        TYPE_APPLE_S5L,
};

struct s3c24xx_uart_info {
        char                    *name;
        enum s3c24xx_port_type  type;
        unsigned int            has_usi;
        unsigned int            port_type;
        unsigned int            fifosize;
        unsigned long           rx_fifomask;
        unsigned long           rx_fifoshift;
        unsigned long           rx_fifofull;
        unsigned long           tx_fifomask;
        unsigned long           tx_fifoshift;
        unsigned long           tx_fifofull;
        unsigned int            def_clk_sel;
        unsigned long           num_clks;
        unsigned long           clksel_mask;
        unsigned long           clksel_shift;
        unsigned long           ucon_mask;

        /* uart port features */

        unsigned int            has_divslot:1;
};

struct s3c24xx_serial_drv_data {
        struct s3c24xx_uart_info        *info;
        struct s3c2410_uartcfg          *def_cfg;
        unsigned int                    fifosize[CONFIG_SERIAL_SAMSUNG_UARTS];
};

struct s3c24xx_uart_dma {
        unsigned int                    rx_chan_id;
        unsigned int                    tx_chan_id;

        struct dma_slave_config         rx_conf;
        struct dma_slave_config         tx_conf;

        struct dma_chan                 *rx_chan;
        struct dma_chan                 *tx_chan;

        dma_addr_t                      rx_addr;
        dma_addr_t                      tx_addr;

        dma_cookie_t                    rx_cookie;
        dma_cookie_t                    tx_cookie;

        char                            *rx_buf;

        dma_addr_t                      tx_transfer_addr;

        size_t                          rx_size;
        size_t                          tx_size;

        struct dma_async_tx_descriptor  *tx_desc;
        struct dma_async_tx_descriptor  *rx_desc;

        int                             tx_bytes_requested;
        int                             rx_bytes_requested;
};

struct s3c24xx_uart_port {
        unsigned char                   rx_claimed;
        unsigned char                   tx_claimed;
        unsigned char                   rx_enabled;
        unsigned char                   tx_enabled;
        unsigned int                    pm_level;
        unsigned long                   baudclk_rate;
        unsigned int                    min_dma_size;

        unsigned int                    rx_irq;
        unsigned int                    tx_irq;

        unsigned int                    tx_in_progress;
        unsigned int                    tx_mode;
        unsigned int                    rx_mode;

        struct s3c24xx_uart_info        *info;
        struct clk                      *clk;
        struct clk                      *baudclk;
        struct uart_port                port;
        struct s3c24xx_serial_drv_data  *drv_data;

        /* reference to platform data */
        struct s3c2410_uartcfg          *cfg;

        struct s3c24xx_uart_dma         *dma;

#ifdef CONFIG_ARM_S3C24XX_CPUFREQ
        struct notifier_block           freq_transition;
#endif
};

static void s3c24xx_serial_tx_chars(struct s3c24xx_uart_port *ourport);

/* conversion functions */

#define s3c24xx_dev_to_port(__dev) dev_get_drvdata(__dev)

/* register access controls */

#define portaddr(port, reg) ((port)->membase + (reg))
#define portaddrl(port, reg) \
        ((unsigned long *)(unsigned long)((port)->membase + (reg)))

static u32 rd_reg(struct uart_port *port, u32 reg)
{
        switch (port->iotype) {
        case UPIO_MEM:
                return readb_relaxed(portaddr(port, reg));
        case UPIO_MEM32:
                return readl_relaxed(portaddr(port, reg));
        default:
                return 0;
        }
        return 0;
}

#define rd_regl(port, reg) (readl_relaxed(portaddr(port, reg)))

static void wr_reg(struct uart_port *port, u32 reg, u32 val)
{
        switch (port->iotype) {
        case UPIO_MEM:
                writeb_relaxed(val, portaddr(port, reg));
                break;
        case UPIO_MEM32:
                writel_relaxed(val, portaddr(port, reg));
                break;
        }
}

#define wr_regl(port, reg, val) writel_relaxed(val, portaddr(port, reg))

/* Byte-order aware bit setting/clearing functions. */

static inline void s3c24xx_set_bit(struct uart_port *port, int idx,
                                   unsigned int reg)
{
        unsigned long flags;
        u32 val;

        local_irq_save(flags);
        val = rd_regl(port, reg);
        val |= (1 << idx);
        wr_regl(port, reg, val);
        local_irq_restore(flags);
}

static inline void s3c24xx_clear_bit(struct uart_port *port, int idx,
                                     unsigned int reg)
{
        unsigned long flags;
        u32 val;

        local_irq_save(flags);
        val = rd_regl(port, reg);
        val &= ~(1 << idx);
        wr_regl(port, reg, val);
        local_irq_restore(flags);
}

static inline struct s3c24xx_uart_port *to_ourport(struct uart_port *port)
{
        return container_of(port, struct s3c24xx_uart_port, port);
}

/* translate a port to the device name */

static inline const char *s3c24xx_serial_portname(struct uart_port *port)
{
        return to_platform_device(port->dev)->name;
}

static int s3c24xx_serial_txempty_nofifo(struct uart_port *port)
{
        return rd_regl(port, S3C2410_UTRSTAT) & S3C2410_UTRSTAT_TXE;
}

static void s3c24xx_serial_rx_enable(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);
        unsigned long flags;
        unsigned int ucon, ufcon;
        int count = 10000;

        spin_lock_irqsave(&port->lock, flags);

        while (--count && !s3c24xx_serial_txempty_nofifo(port))
                udelay(100);

        ufcon = rd_regl(port, S3C2410_UFCON);
        ufcon |= S3C2410_UFCON_RESETRX;
        wr_regl(port, S3C2410_UFCON, ufcon);

        ucon = rd_regl(port, S3C2410_UCON);
        ucon |= S3C2410_UCON_RXIRQMODE;
        wr_regl(port, S3C2410_UCON, ucon);

        ourport->rx_enabled = 1;
        spin_unlock_irqrestore(&port->lock, flags);
}

static void s3c24xx_serial_rx_disable(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);
        unsigned long flags;
        unsigned int ucon;

        spin_lock_irqsave(&port->lock, flags);

        ucon = rd_regl(port, S3C2410_UCON);
        ucon &= ~S3C2410_UCON_RXIRQMODE;
        wr_regl(port, S3C2410_UCON, ucon);

        ourport->rx_enabled = 0;
        spin_unlock_irqrestore(&port->lock, flags);
}

static void s3c24xx_serial_stop_tx(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);
        struct s3c24xx_uart_dma *dma = ourport->dma;
        struct circ_buf *xmit = &port->state->xmit;
        struct dma_tx_state state;
        int count;

        if (!ourport->tx_enabled)
                return;

        switch (ourport->info->type) {
        case TYPE_S3C6400:
                s3c24xx_set_bit(port, S3C64XX_UINTM_TXD, S3C64XX_UINTM);
                break;
        case TYPE_APPLE_S5L:
                s3c24xx_clear_bit(port, APPLE_S5L_UCON_TXTHRESH_ENA, S3C2410_UCON);
                break;
        default:
                disable_irq_nosync(ourport->tx_irq);
                break;
        }

        if (dma && dma->tx_chan && ourport->tx_in_progress == S3C24XX_TX_DMA) {
                dmaengine_pause(dma->tx_chan);
                dmaengine_tx_status(dma->tx_chan, dma->tx_cookie, &state);
                dmaengine_terminate_all(dma->tx_chan);
                dma_sync_single_for_cpu(dma->tx_chan->device->dev,
                                        dma->tx_transfer_addr, dma->tx_size,
                                        DMA_TO_DEVICE);
                async_tx_ack(dma->tx_desc);
                count = dma->tx_bytes_requested - state.residue;
                xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
                port->icount.tx += count;
        }

        ourport->tx_enabled = 0;
        ourport->tx_in_progress = 0;

        if (port->flags & UPF_CONS_FLOW)
                s3c24xx_serial_rx_enable(port);

        ourport->tx_mode = 0;
}

static void s3c24xx_serial_start_next_tx(struct s3c24xx_uart_port *ourport);

static void s3c24xx_serial_tx_dma_complete(void *args)
{
        struct s3c24xx_uart_port *ourport = args;
        struct uart_port *port = &ourport->port;
        struct circ_buf *xmit = &port->state->xmit;
        struct s3c24xx_uart_dma *dma = ourport->dma;
        struct dma_tx_state state;
        unsigned long flags;
        int count;

        dmaengine_tx_status(dma->tx_chan, dma->tx_cookie, &state);
        count = dma->tx_bytes_requested - state.residue;
        async_tx_ack(dma->tx_desc);

        dma_sync_single_for_cpu(dma->tx_chan->device->dev,
                                dma->tx_transfer_addr, dma->tx_size,
                                DMA_TO_DEVICE);

        spin_lock_irqsave(&port->lock, flags);

        xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
        port->icount.tx += count;
        ourport->tx_in_progress = 0;

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

        s3c24xx_serial_start_next_tx(ourport);
        spin_unlock_irqrestore(&port->lock, flags);
}

static void enable_tx_dma(struct s3c24xx_uart_port *ourport)
{
        struct uart_port *port = &ourport->port;
        u32 ucon;

        /* Mask Tx interrupt */
        switch (ourport->info->type) {
        case TYPE_S3C6400:
                s3c24xx_set_bit(port, S3C64XX_UINTM_TXD, S3C64XX_UINTM);
                break;
        case TYPE_APPLE_S5L:
                WARN_ON(1); // No DMA
                break;
        default:
                disable_irq_nosync(ourport->tx_irq);
                break;
        }

        /* Enable tx dma mode */
        ucon = rd_regl(port, S3C2410_UCON);
        ucon &= ~(S3C64XX_UCON_TXBURST_MASK | S3C64XX_UCON_TXMODE_MASK);
        ucon |= (dma_get_cache_alignment() >= 16) ?
                S3C64XX_UCON_TXBURST_16 : S3C64XX_UCON_TXBURST_1;
        ucon |= S3C64XX_UCON_TXMODE_DMA;
        wr_regl(port,  S3C2410_UCON, ucon);

        ourport->tx_mode = S3C24XX_TX_DMA;
}

static void enable_tx_pio(struct s3c24xx_uart_port *ourport)
{
        struct uart_port *port = &ourport->port;
        u32 ucon, ufcon;

        /* Set ufcon txtrig */
        ourport->tx_in_progress = S3C24XX_TX_PIO;
        ufcon = rd_regl(port, S3C2410_UFCON);
        wr_regl(port,  S3C2410_UFCON, ufcon);

        /* Enable tx pio mode */
        ucon = rd_regl(port, S3C2410_UCON);
        ucon &= ~(S3C64XX_UCON_TXMODE_MASK);
        ucon |= S3C64XX_UCON_TXMODE_CPU;
        wr_regl(port,  S3C2410_UCON, ucon);

        /* Unmask Tx interrupt */
        switch (ourport->info->type) {
        case TYPE_S3C6400:
                s3c24xx_clear_bit(port, S3C64XX_UINTM_TXD,
                                  S3C64XX_UINTM);
                break;
        case TYPE_APPLE_S5L:
                ucon |= APPLE_S5L_UCON_TXTHRESH_ENA_MSK;
                wr_regl(port, S3C2410_UCON, ucon);
                break;
        default:
                enable_irq(ourport->tx_irq);
                break;
        }

        ourport->tx_mode = S3C24XX_TX_PIO;

        /*
         * The Apple version only has edge triggered TX IRQs, so we need
         * to kick off the process by sending some characters here.
         */
        if (ourport->info->type == TYPE_APPLE_S5L)
                s3c24xx_serial_tx_chars(ourport);
}

static void s3c24xx_serial_start_tx_pio(struct s3c24xx_uart_port *ourport)
{
        if (ourport->tx_mode != S3C24XX_TX_PIO)
                enable_tx_pio(ourport);
}

static int s3c24xx_serial_start_tx_dma(struct s3c24xx_uart_port *ourport,
                                      unsigned int count)
{
        struct uart_port *port = &ourport->port;
        struct circ_buf *xmit = &port->state->xmit;
        struct s3c24xx_uart_dma *dma = ourport->dma;

        if (ourport->tx_mode != S3C24XX_TX_DMA)
                enable_tx_dma(ourport);

        dma->tx_size = count & ~(dma_get_cache_alignment() - 1);
        dma->tx_transfer_addr = dma->tx_addr + xmit->tail;

        dma_sync_single_for_device(dma->tx_chan->device->dev,
                                   dma->tx_transfer_addr, dma->tx_size,
                                   DMA_TO_DEVICE);

        dma->tx_desc = dmaengine_prep_slave_single(dma->tx_chan,
                                dma->tx_transfer_addr, dma->tx_size,
                                DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
        if (!dma->tx_desc) {
                dev_err(ourport->port.dev, "Unable to get desc for Tx\n");
                return -EIO;
        }

        dma->tx_desc->callback = s3c24xx_serial_tx_dma_complete;
        dma->tx_desc->callback_param = ourport;
        dma->tx_bytes_requested = dma->tx_size;

        ourport->tx_in_progress = S3C24XX_TX_DMA;
        dma->tx_cookie = dmaengine_submit(dma->tx_desc);
        dma_async_issue_pending(dma->tx_chan);
        return 0;
}

static void s3c24xx_serial_start_next_tx(struct s3c24xx_uart_port *ourport)
{
        struct uart_port *port = &ourport->port;
        struct circ_buf *xmit = &port->state->xmit;
        unsigned long count;

        /* Get data size up to the end of buffer */
        count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);

        if (!count) {
                s3c24xx_serial_stop_tx(port);
                return;
        }

        if (!ourport->dma || !ourport->dma->tx_chan ||
            count < ourport->min_dma_size ||
            xmit->tail & (dma_get_cache_alignment() - 1))
                s3c24xx_serial_start_tx_pio(ourport);
        else
                s3c24xx_serial_start_tx_dma(ourport, count);
}

static void s3c24xx_serial_start_tx(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);
        struct circ_buf *xmit = &port->state->xmit;

        if (!ourport->tx_enabled) {
                if (port->flags & UPF_CONS_FLOW)
                        s3c24xx_serial_rx_disable(port);

                ourport->tx_enabled = 1;
                if (!ourport->dma || !ourport->dma->tx_chan)
                        s3c24xx_serial_start_tx_pio(ourport);
        }

        if (ourport->dma && ourport->dma->tx_chan) {
                if (!uart_circ_empty(xmit) && !ourport->tx_in_progress)
                        s3c24xx_serial_start_next_tx(ourport);
        }
}

static void s3c24xx_uart_copy_rx_to_tty(struct s3c24xx_uart_port *ourport,
                struct tty_port *tty, int count)
{
        struct s3c24xx_uart_dma *dma = ourport->dma;
        int copied;

        if (!count)
                return;

        dma_sync_single_for_cpu(dma->rx_chan->device->dev, dma->rx_addr,
                                dma->rx_size, DMA_FROM_DEVICE);

        ourport->port.icount.rx += count;
        if (!tty) {
                dev_err(ourport->port.dev, "No tty port\n");
                return;
        }
        copied = tty_insert_flip_string(tty,
                        ((unsigned char *)(ourport->dma->rx_buf)), count);
        if (copied != count) {
                WARN_ON(1);
                dev_err(ourport->port.dev, "RxData copy to tty layer failed\n");
        }
}

static void s3c24xx_serial_stop_rx(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);
        struct s3c24xx_uart_dma *dma = ourport->dma;
        struct tty_port *t = &port->state->port;
        struct dma_tx_state state;
        enum dma_status dma_status;
        unsigned int received;

        if (ourport->rx_enabled) {
                dev_dbg(port->dev, "stopping rx\n");
                switch (ourport->info->type) {
                case TYPE_S3C6400:
                        s3c24xx_set_bit(port, S3C64XX_UINTM_RXD,
                                        S3C64XX_UINTM);
                        break;
                case TYPE_APPLE_S5L:
                        s3c24xx_clear_bit(port, APPLE_S5L_UCON_RXTHRESH_ENA, S3C2410_UCON);
                        s3c24xx_clear_bit(port, APPLE_S5L_UCON_RXTO_ENA, S3C2410_UCON);
                        break;
                default:
                        disable_irq_nosync(ourport->rx_irq);
                        break;
                }
                ourport->rx_enabled = 0;
        }
        if (dma && dma->rx_chan) {
                dmaengine_pause(dma->tx_chan);
                dma_status = dmaengine_tx_status(dma->rx_chan,
                                dma->rx_cookie, &state);
                if (dma_status == DMA_IN_PROGRESS ||
                        dma_status == DMA_PAUSED) {
                        received = dma->rx_bytes_requested - state.residue;
                        dmaengine_terminate_all(dma->rx_chan);
                        s3c24xx_uart_copy_rx_to_tty(ourport, t, received);
                }
        }
}

static inline struct s3c24xx_uart_info
        *s3c24xx_port_to_info(struct uart_port *port)
{
        return to_ourport(port)->info;
}

static inline struct s3c2410_uartcfg
        *s3c24xx_port_to_cfg(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport;

        if (port->dev == NULL)
                return NULL;

        ourport = container_of(port, struct s3c24xx_uart_port, port);
        return ourport->cfg;
}

static int s3c24xx_serial_rx_fifocnt(struct s3c24xx_uart_port *ourport,
                                     unsigned long ufstat)
{
        struct s3c24xx_uart_info *info = ourport->info;

        if (ufstat & info->rx_fifofull)
                return ourport->port.fifosize;

        return (ufstat & info->rx_fifomask) >> info->rx_fifoshift;
}

static void s3c64xx_start_rx_dma(struct s3c24xx_uart_port *ourport);
static void s3c24xx_serial_rx_dma_complete(void *args)
{
        struct s3c24xx_uart_port *ourport = args;
        struct uart_port *port = &ourport->port;

        struct s3c24xx_uart_dma *dma = ourport->dma;
        struct tty_port *t = &port->state->port;
        struct tty_struct *tty = tty_port_tty_get(&ourport->port.state->port);

        struct dma_tx_state state;
        unsigned long flags;
        int received;

        dmaengine_tx_status(dma->rx_chan,  dma->rx_cookie, &state);
        received  = dma->rx_bytes_requested - state.residue;
        async_tx_ack(dma->rx_desc);

        spin_lock_irqsave(&port->lock, flags);

        if (received)
                s3c24xx_uart_copy_rx_to_tty(ourport, t, received);

        if (tty) {
                tty_flip_buffer_push(t);
                tty_kref_put(tty);
        }

        s3c64xx_start_rx_dma(ourport);

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

static void s3c64xx_start_rx_dma(struct s3c24xx_uart_port *ourport)
{
        struct s3c24xx_uart_dma *dma = ourport->dma;

        dma_sync_single_for_device(dma->rx_chan->device->dev, dma->rx_addr,
                                   dma->rx_size, DMA_FROM_DEVICE);

        dma->rx_desc = dmaengine_prep_slave_single(dma->rx_chan,
                                dma->rx_addr, dma->rx_size, DMA_DEV_TO_MEM,
                                DMA_PREP_INTERRUPT);
        if (!dma->rx_desc) {
                dev_err(ourport->port.dev, "Unable to get desc for Rx\n");
                return;
        }

        dma->rx_desc->callback = s3c24xx_serial_rx_dma_complete;
        dma->rx_desc->callback_param = ourport;
        dma->rx_bytes_requested = dma->rx_size;

        dma->rx_cookie = dmaengine_submit(dma->rx_desc);
        dma_async_issue_pending(dma->rx_chan);
}

/* ? - where has parity gone?? */
#define S3C2410_UERSTAT_PARITY (0x1000)

static void enable_rx_dma(struct s3c24xx_uart_port *ourport)
{
        struct uart_port *port = &ourport->port;
        unsigned int ucon;

        /* set Rx mode to DMA mode */
        ucon = rd_regl(port, S3C2410_UCON);
        ucon &= ~(S3C64XX_UCON_RXBURST_MASK |
                        S3C64XX_UCON_TIMEOUT_MASK |
                        S3C64XX_UCON_EMPTYINT_EN |
                        S3C64XX_UCON_DMASUS_EN |
                        S3C64XX_UCON_TIMEOUT_EN |
                        S3C64XX_UCON_RXMODE_MASK);
        ucon |= S3C64XX_UCON_RXBURST_16 |
                        0xf << S3C64XX_UCON_TIMEOUT_SHIFT |
                        S3C64XX_UCON_EMPTYINT_EN |
                        S3C64XX_UCON_TIMEOUT_EN |
                        S3C64XX_UCON_RXMODE_DMA;
        wr_regl(port, S3C2410_UCON, ucon);

        ourport->rx_mode = S3C24XX_RX_DMA;
}

static void enable_rx_pio(struct s3c24xx_uart_port *ourport)
{
        struct uart_port *port = &ourport->port;
        unsigned int ucon;

        /* set Rx mode to DMA mode */
        ucon = rd_regl(port, S3C2410_UCON);
        ucon &= ~S3C64XX_UCON_RXMODE_MASK;
        ucon |= S3C64XX_UCON_RXMODE_CPU;

        /* Apple types use these bits for IRQ masks */
        if (ourport->info->type != TYPE_APPLE_S5L) {
                ucon &= ~(S3C64XX_UCON_TIMEOUT_MASK |
                                S3C64XX_UCON_EMPTYINT_EN |
                                S3C64XX_UCON_DMASUS_EN |
                                S3C64XX_UCON_TIMEOUT_EN);
                ucon |= 0xf << S3C64XX_UCON_TIMEOUT_SHIFT |
                                S3C64XX_UCON_TIMEOUT_EN;
        }
        wr_regl(port, S3C2410_UCON, ucon);

        ourport->rx_mode = S3C24XX_RX_PIO;
}

static void s3c24xx_serial_rx_drain_fifo(struct s3c24xx_uart_port *ourport);

static irqreturn_t s3c24xx_serial_rx_chars_dma(void *dev_id)
{
        unsigned int utrstat, received;
        struct s3c24xx_uart_port *ourport = dev_id;
        struct uart_port *port = &ourport->port;
        struct s3c24xx_uart_dma *dma = ourport->dma;
        struct tty_struct *tty = tty_port_tty_get(&ourport->port.state->port);
        struct tty_port *t = &port->state->port;
        struct dma_tx_state state;

        utrstat = rd_regl(port, S3C2410_UTRSTAT);
        rd_regl(port, S3C2410_UFSTAT);

        spin_lock(&port->lock);

        if (!(utrstat & S3C2410_UTRSTAT_TIMEOUT)) {
                s3c64xx_start_rx_dma(ourport);
                if (ourport->rx_mode == S3C24XX_RX_PIO)
                        enable_rx_dma(ourport);
                goto finish;
        }

        if (ourport->rx_mode == S3C24XX_RX_DMA) {
                dmaengine_pause(dma->rx_chan);
                dmaengine_tx_status(dma->rx_chan, dma->rx_cookie, &state);
                dmaengine_terminate_all(dma->rx_chan);
                received = dma->rx_bytes_requested - state.residue;
                s3c24xx_uart_copy_rx_to_tty(ourport, t, received);

                enable_rx_pio(ourport);
        }

        s3c24xx_serial_rx_drain_fifo(ourport);

        if (tty) {
                tty_flip_buffer_push(t);
                tty_kref_put(tty);
        }

        wr_regl(port, S3C2410_UTRSTAT, S3C2410_UTRSTAT_TIMEOUT);

finish:
        spin_unlock(&port->lock);

        return IRQ_HANDLED;
}

static void s3c24xx_serial_rx_drain_fifo(struct s3c24xx_uart_port *ourport)
{
        struct uart_port *port = &ourport->port;
        unsigned int ufcon, ch, flag, ufstat, uerstat;
        unsigned int fifocnt = 0;
        int max_count = port->fifosize;

        while (max_count-- > 0) {
                /*
                 * Receive all characters known to be in FIFO
                 * before reading FIFO level again
                 */
                if (fifocnt == 0) {
                        ufstat = rd_regl(port, S3C2410_UFSTAT);
                        fifocnt = s3c24xx_serial_rx_fifocnt(ourport, ufstat);
                        if (fifocnt == 0)
                                break;
                }
                fifocnt--;

                uerstat = rd_regl(port, S3C2410_UERSTAT);
                ch = rd_reg(port, S3C2410_URXH);

                if (port->flags & UPF_CONS_FLOW) {
                        int txe = s3c24xx_serial_txempty_nofifo(port);

                        if (ourport->rx_enabled) {
                                if (!txe) {
                                        ourport->rx_enabled = 0;
                                        continue;
                                }
                        } else {
                                if (txe) {
                                        ufcon = rd_regl(port, S3C2410_UFCON);
                                        ufcon |= S3C2410_UFCON_RESETRX;
                                        wr_regl(port, S3C2410_UFCON, ufcon);
                                        ourport->rx_enabled = 1;
                                        return;
                                }
                                continue;
                        }
                }

                /* insert the character into the buffer */

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

                if (unlikely(uerstat & S3C2410_UERSTAT_ANY)) {
                        dev_dbg(port->dev,
                                "rxerr: port ch=0x%02x, rxs=0x%08x\n",
                                ch, uerstat);

                        /* check for break */
                        if (uerstat & S3C2410_UERSTAT_BREAK) {
                                dev_dbg(port->dev, "break!\n");
                                port->icount.brk++;
                                if (uart_handle_break(port))
                                        continue; /* Ignore character */
                        }

                        if (uerstat & S3C2410_UERSTAT_FRAME)
                                port->icount.frame++;
                        if (uerstat & S3C2410_UERSTAT_OVERRUN)
                                port->icount.overrun++;

                        uerstat &= port->read_status_mask;

                        if (uerstat & S3C2410_UERSTAT_BREAK)
                                flag = TTY_BREAK;
                        else if (uerstat & S3C2410_UERSTAT_PARITY)
                                flag = TTY_PARITY;
                        else if (uerstat & (S3C2410_UERSTAT_FRAME |
                                            S3C2410_UERSTAT_OVERRUN))
                                flag = TTY_FRAME;
                }

                if (uart_handle_sysrq_char(port, ch))
                        continue; /* Ignore character */

                uart_insert_char(port, uerstat, S3C2410_UERSTAT_OVERRUN,
                                 ch, flag);
        }

        tty_flip_buffer_push(&port->state->port);
}

static irqreturn_t s3c24xx_serial_rx_chars_pio(void *dev_id)
{
        struct s3c24xx_uart_port *ourport = dev_id;
        struct uart_port *port = &ourport->port;

        spin_lock(&port->lock);
        s3c24xx_serial_rx_drain_fifo(ourport);
        spin_unlock(&port->lock);

        return IRQ_HANDLED;
}

static irqreturn_t s3c24xx_serial_rx_irq(int irq, void *dev_id)
{
        struct s3c24xx_uart_port *ourport = dev_id;

        if (ourport->dma && ourport->dma->rx_chan)
                return s3c24xx_serial_rx_chars_dma(dev_id);
        return s3c24xx_serial_rx_chars_pio(dev_id);
}

static void s3c24xx_serial_tx_chars(struct s3c24xx_uart_port *ourport)
{
        struct uart_port *port = &ourport->port;
        struct circ_buf *xmit = &port->state->xmit;
        int count, dma_count = 0;

        count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);

        if (ourport->dma && ourport->dma->tx_chan &&
            count >= ourport->min_dma_size) {
                int align = dma_get_cache_alignment() -
                        (xmit->tail & (dma_get_cache_alignment() - 1));
                if (count - align >= ourport->min_dma_size) {
                        dma_count = count - align;
                        count = align;
                }
        }

        if (port->x_char) {
                wr_reg(port, S3C2410_UTXH, port->x_char);
                port->icount.tx++;
                port->x_char = 0;
                return;
        }

        /* if there isn't anything more to transmit, or the uart is now
         * stopped, disable the uart and exit
         */

        if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
                s3c24xx_serial_stop_tx(port);
                return;
        }

        /* try and drain the buffer... */

        if (count > port->fifosize) {
                count = port->fifosize;
                dma_count = 0;
        }

        while (!uart_circ_empty(xmit) && count > 0) {
                if (rd_regl(port, S3C2410_UFSTAT) & ourport->info->tx_fifofull)
                        break;

                wr_reg(port, S3C2410_UTXH, xmit->buf[xmit->tail]);
                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                port->icount.tx++;
                count--;
        }

        if (!count && dma_count) {
                s3c24xx_serial_start_tx_dma(ourport, dma_count);
                return;
        }

        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) {
                spin_unlock(&port->lock);
                uart_write_wakeup(port);
                spin_lock(&port->lock);
        }

        if (uart_circ_empty(xmit))
                s3c24xx_serial_stop_tx(port);
}

static irqreturn_t s3c24xx_serial_tx_irq(int irq, void *id)
{
        struct s3c24xx_uart_port *ourport = id;
        struct uart_port *port = &ourport->port;

        spin_lock(&port->lock);

        s3c24xx_serial_tx_chars(ourport);

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

/* interrupt handler for s3c64xx and later SoC's.*/
static irqreturn_t s3c64xx_serial_handle_irq(int irq, void *id)
{
        struct s3c24xx_uart_port *ourport = id;
        struct uart_port *port = &ourport->port;
        unsigned int pend = rd_regl(port, S3C64XX_UINTP);
        irqreturn_t ret = IRQ_HANDLED;

        if (pend & S3C64XX_UINTM_RXD_MSK) {
                ret = s3c24xx_serial_rx_irq(irq, id);
                wr_regl(port, S3C64XX_UINTP, S3C64XX_UINTM_RXD_MSK);
        }
        if (pend & S3C64XX_UINTM_TXD_MSK) {
                ret = s3c24xx_serial_tx_irq(irq, id);
                wr_regl(port, S3C64XX_UINTP, S3C64XX_UINTM_TXD_MSK);
        }
        return ret;
}

/* interrupt handler for Apple SoC's.*/
static irqreturn_t apple_serial_handle_irq(int irq, void *id)
{
        struct s3c24xx_uart_port *ourport = id;
        struct uart_port *port = &ourport->port;
        unsigned int pend = rd_regl(port, S3C2410_UTRSTAT);
        irqreturn_t ret = IRQ_NONE;

        if (pend & (APPLE_S5L_UTRSTAT_RXTHRESH | APPLE_S5L_UTRSTAT_RXTO)) {
                wr_regl(port, S3C2410_UTRSTAT,
                        APPLE_S5L_UTRSTAT_RXTHRESH | APPLE_S5L_UTRSTAT_RXTO);
                ret = s3c24xx_serial_rx_irq(irq, id);
        }
        if (pend & APPLE_S5L_UTRSTAT_TXTHRESH) {
                wr_regl(port, S3C2410_UTRSTAT, APPLE_S5L_UTRSTAT_TXTHRESH);
                ret = s3c24xx_serial_tx_irq(irq, id);
        }

        return ret;
}

static unsigned int s3c24xx_serial_tx_empty(struct uart_port *port)
{
        struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
        unsigned long ufstat = rd_regl(port, S3C2410_UFSTAT);
        unsigned long ufcon = rd_regl(port, S3C2410_UFCON);

        if (ufcon & S3C2410_UFCON_FIFOMODE) {
                if ((ufstat & info->tx_fifomask) != 0 ||
                    (ufstat & info->tx_fifofull))
                        return 0;

                return 1;
        }

        return s3c24xx_serial_txempty_nofifo(port);
}

/* no modem control lines */
static unsigned int s3c24xx_serial_get_mctrl(struct uart_port *port)
{
        unsigned int umstat = rd_reg(port, S3C2410_UMSTAT);

        if (umstat & S3C2410_UMSTAT_CTS)
                return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
        else
                return TIOCM_CAR | TIOCM_DSR;
}

static void s3c24xx_serial_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        unsigned int umcon = rd_regl(port, S3C2410_UMCON);

        if (mctrl & TIOCM_RTS)
                umcon |= S3C2410_UMCOM_RTS_LOW;
        else
                umcon &= ~S3C2410_UMCOM_RTS_LOW;

        wr_regl(port, S3C2410_UMCON, umcon);
}

static void s3c24xx_serial_break_ctl(struct uart_port *port, int break_state)
{
        unsigned long flags;
        unsigned int ucon;

        spin_lock_irqsave(&port->lock, flags);

        ucon = rd_regl(port, S3C2410_UCON);

        if (break_state)
                ucon |= S3C2410_UCON_SBREAK;
        else
                ucon &= ~S3C2410_UCON_SBREAK;

        wr_regl(port, S3C2410_UCON, ucon);

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

static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p)
{
        struct s3c24xx_uart_dma *dma = p->dma;
        struct dma_slave_caps dma_caps;
        const char *reason = NULL;
        int ret;

        /* Default slave configuration parameters */
        dma->rx_conf.direction          = DMA_DEV_TO_MEM;
        dma->rx_conf.src_addr_width     = DMA_SLAVE_BUSWIDTH_1_BYTE;
        dma->rx_conf.src_addr           = p->port.mapbase + S3C2410_URXH;
        dma->rx_conf.src_maxburst       = 1;

        dma->tx_conf.direction          = DMA_MEM_TO_DEV;
        dma->tx_conf.dst_addr_width     = DMA_SLAVE_BUSWIDTH_1_BYTE;
        dma->tx_conf.dst_addr           = p->port.mapbase + S3C2410_UTXH;
        dma->tx_conf.dst_maxburst       = 1;

        dma->rx_chan = dma_request_chan(p->port.dev, "rx");

        if (IS_ERR(dma->rx_chan)) {
                reason = "DMA RX channel request failed";
                ret = PTR_ERR(dma->rx_chan);
                goto err_warn;
        }

        ret = dma_get_slave_caps(dma->rx_chan, &dma_caps);
        if (ret < 0 ||
            dma_caps.residue_granularity < DMA_RESIDUE_GRANULARITY_BURST) {
                reason = "insufficient DMA RX engine capabilities";
                ret = -EOPNOTSUPP;
                goto err_release_rx;
        }

        dmaengine_slave_config(dma->rx_chan, &dma->rx_conf);

        dma->tx_chan = dma_request_chan(p->port.dev, "tx");
        if (IS_ERR(dma->tx_chan)) {
                reason = "DMA TX channel request failed";
                ret = PTR_ERR(dma->tx_chan);
                goto err_release_rx;
        }

        ret = dma_get_slave_caps(dma->tx_chan, &dma_caps);
        if (ret < 0 ||
            dma_caps.residue_granularity < DMA_RESIDUE_GRANULARITY_BURST) {
                reason = "insufficient DMA TX engine capabilities";
                ret = -EOPNOTSUPP;
                goto err_release_tx;
        }

        dmaengine_slave_config(dma->tx_chan, &dma->tx_conf);

        /* RX buffer */
        dma->rx_size = PAGE_SIZE;

        dma->rx_buf = kmalloc(dma->rx_size, GFP_KERNEL);
        if (!dma->rx_buf) {
                ret = -ENOMEM;
                goto err_release_tx;
        }

        dma->rx_addr = dma_map_single(dma->rx_chan->device->dev, dma->rx_buf,
                                      dma->rx_size, DMA_FROM_DEVICE);
        if (dma_mapping_error(dma->rx_chan->device->dev, dma->rx_addr)) {
                reason = "DMA mapping error for RX buffer";
                ret = -EIO;
                goto err_free_rx;
        }

        /* TX buffer */
        dma->tx_addr = dma_map_single(dma->tx_chan->device->dev,
                                      p->port.state->xmit.buf, UART_XMIT_SIZE,
                                      DMA_TO_DEVICE);
        if (dma_mapping_error(dma->tx_chan->device->dev, dma->tx_addr)) {
                reason = "DMA mapping error for TX buffer";
                ret = -EIO;
                goto err_unmap_rx;
        }

        return 0;

err_unmap_rx:
        dma_unmap_single(dma->rx_chan->device->dev, dma->rx_addr,
                         dma->rx_size, DMA_FROM_DEVICE);
err_free_rx:
        kfree(dma->rx_buf);
err_release_tx:
        dma_release_channel(dma->tx_chan);
err_release_rx:
        dma_release_channel(dma->rx_chan);
err_warn:
        if (reason)
                dev_warn(p->port.dev, "%s, DMA will not be used\n", reason);
        return ret;
}

static void s3c24xx_serial_release_dma(struct s3c24xx_uart_port *p)
{
        struct s3c24xx_uart_dma *dma = p->dma;

        if (dma->rx_chan) {
                dmaengine_terminate_all(dma->rx_chan);
                dma_unmap_single(dma->rx_chan->device->dev, dma->rx_addr,
                                 dma->rx_size, DMA_FROM_DEVICE);
                kfree(dma->rx_buf);
                dma_release_channel(dma->rx_chan);
                dma->rx_chan = NULL;
        }

        if (dma->tx_chan) {
                dmaengine_terminate_all(dma->tx_chan);
                dma_unmap_single(dma->tx_chan->device->dev, dma->tx_addr,
                                 UART_XMIT_SIZE, DMA_TO_DEVICE);
                dma_release_channel(dma->tx_chan);
                dma->tx_chan = NULL;
        }
}

static void s3c24xx_serial_shutdown(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);

        if (ourport->tx_claimed) {
                free_irq(ourport->tx_irq, ourport);
                ourport->tx_enabled = 0;
                ourport->tx_claimed = 0;
                ourport->tx_mode = 0;
        }

        if (ourport->rx_claimed) {
                free_irq(ourport->rx_irq, ourport);
                ourport->rx_claimed = 0;
                ourport->rx_enabled = 0;
        }

        if (ourport->dma)
                s3c24xx_serial_release_dma(ourport);

        ourport->tx_in_progress = 0;
}

static void s3c64xx_serial_shutdown(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);

        ourport->tx_enabled = 0;
        ourport->tx_mode = 0;
        ourport->rx_enabled = 0;

        free_irq(port->irq, ourport);

        wr_regl(port, S3C64XX_UINTP, 0xf);
        wr_regl(port, S3C64XX_UINTM, 0xf);

        if (ourport->dma)
                s3c24xx_serial_release_dma(ourport);

        ourport->tx_in_progress = 0;
}

static void apple_s5l_serial_shutdown(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);

        unsigned int ucon;

        ucon = rd_regl(port, S3C2410_UCON);
        ucon &= ~(APPLE_S5L_UCON_TXTHRESH_ENA_MSK |
                  APPLE_S5L_UCON_RXTHRESH_ENA_MSK |
                  APPLE_S5L_UCON_RXTO_ENA_MSK);
        wr_regl(port, S3C2410_UCON, ucon);

        wr_regl(port, S3C2410_UTRSTAT, APPLE_S5L_UTRSTAT_ALL_FLAGS);

        free_irq(port->irq, ourport);

        ourport->tx_enabled = 0;
        ourport->tx_mode = 0;
        ourport->rx_enabled = 0;

        if (ourport->dma)
                s3c24xx_serial_release_dma(ourport);

        ourport->tx_in_progress = 0;
}

static int s3c24xx_serial_startup(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);
        int ret;

        ourport->rx_enabled = 1;

        ret = request_irq(ourport->rx_irq, s3c24xx_serial_rx_irq, 0,
                          s3c24xx_serial_portname(port), ourport);

        if (ret != 0) {
                dev_err(port->dev, "cannot get irq %d\n", ourport->rx_irq);
                return ret;
        }

        ourport->rx_claimed = 1;

        dev_dbg(port->dev, "requesting tx irq...\n");

        ourport->tx_enabled = 1;

        ret = request_irq(ourport->tx_irq, s3c24xx_serial_tx_irq, 0,
                          s3c24xx_serial_portname(port), ourport);

        if (ret) {
                dev_err(port->dev, "cannot get irq %d\n", ourport->tx_irq);
                goto err;
        }

        ourport->tx_claimed = 1;

        /* the port reset code should have done the correct
         * register setup for the port controls
         */

        return ret;

err:
        s3c24xx_serial_shutdown(port);
        return ret;
}

static int s3c64xx_serial_startup(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);
        unsigned long flags;
        unsigned int ufcon;
        int ret;

        wr_regl(port, S3C64XX_UINTM, 0xf);
        if (ourport->dma) {
                ret = s3c24xx_serial_request_dma(ourport);
                if (ret < 0) {
                        devm_kfree(port->dev, ourport->dma);
                        ourport->dma = NULL;
                }
        }

        ret = request_irq(port->irq, s3c64xx_serial_handle_irq, IRQF_SHARED,
                          s3c24xx_serial_portname(port), ourport);
        if (ret) {
                dev_err(port->dev, "cannot get irq %d\n", port->irq);
                return ret;
        }

        /* For compatibility with s3c24xx Soc's */
        ourport->rx_enabled = 1;
        ourport->tx_enabled = 0;

        spin_lock_irqsave(&port->lock, flags);

        ufcon = rd_regl(port, S3C2410_UFCON);
        ufcon |= S3C2410_UFCON_RESETRX | S5PV210_UFCON_RXTRIG8;
        if (!uart_console(port))
                ufcon |= S3C2410_UFCON_RESETTX;
        wr_regl(port, S3C2410_UFCON, ufcon);

        enable_rx_pio(ourport);

        spin_unlock_irqrestore(&port->lock, flags);

        /* Enable Rx Interrupt */
        s3c24xx_clear_bit(port, S3C64XX_UINTM_RXD, S3C64XX_UINTM);

        return ret;
}

static int apple_s5l_serial_startup(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);
        unsigned long flags;
        unsigned int ufcon;
        int ret;

        wr_regl(port, S3C2410_UTRSTAT, APPLE_S5L_UTRSTAT_ALL_FLAGS);

        ret = request_irq(port->irq, apple_serial_handle_irq, 0,
                          s3c24xx_serial_portname(port), ourport);
        if (ret) {
                dev_err(port->dev, "cannot get irq %d\n", port->irq);
                return ret;
        }

        /* For compatibility with s3c24xx Soc's */
        ourport->rx_enabled = 1;
        ourport->tx_enabled = 0;

        spin_lock_irqsave(&port->lock, flags);

        ufcon = rd_regl(port, S3C2410_UFCON);
        ufcon |= S3C2410_UFCON_RESETRX | S5PV210_UFCON_RXTRIG8;
        if (!uart_console(port))
                ufcon |= S3C2410_UFCON_RESETTX;
        wr_regl(port, S3C2410_UFCON, ufcon);

        enable_rx_pio(ourport);

        spin_unlock_irqrestore(&port->lock, flags);

        /* Enable Rx Interrupt */
        s3c24xx_set_bit(port, APPLE_S5L_UCON_RXTHRESH_ENA, S3C2410_UCON);
        s3c24xx_set_bit(port, APPLE_S5L_UCON_RXTO_ENA, S3C2410_UCON);

        return ret;
}

static void exynos_usi_init(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);
        struct s3c24xx_uart_info *info = ourport->info;
        unsigned int val;

        if (!info->has_usi)
                return;

        /* Clear the software reset of USI block (it's set at startup) */
        val = rd_regl(port, USI_CON);
        val &= ~USI_CON_RESET_MASK;
        wr_regl(port, USI_CON, val);
        udelay(1);

        /* Continuously provide the clock to USI IP w/o gating (for Rx mode) */
        val = rd_regl(port, USI_OPTION);
        val &= ~USI_OPTION_HWACG_MASK;
        val |= USI_OPTION_HWACG_CLKREQ_ON;
        wr_regl(port, USI_OPTION, val);
}

/* power power management control */

static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level,
                              unsigned int old)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);
        int timeout = 10000;

        ourport->pm_level = level;

        switch (level) {
        case 3:
                while (--timeout && !s3c24xx_serial_txempty_nofifo(port))
                        udelay(100);

                if (!IS_ERR(ourport->baudclk))
                        clk_disable_unprepare(ourport->baudclk);

                clk_disable_unprepare(ourport->clk);
                break;

        case 0:
                clk_prepare_enable(ourport->clk);

                if (!IS_ERR(ourport->baudclk))
                        clk_prepare_enable(ourport->baudclk);

                exynos_usi_init(port);
                break;
        default:
                dev_err(port->dev, "s3c24xx_serial: unknown pm %d\n", level);
        }
}

/* baud rate calculation
 *
 * The UARTs on the S3C2410/S3C2440 can take their clocks from a number
 * of different sources, including the peripheral clock ("pclk") and an
 * external clock ("uclk"). The S3C2440 also adds the core clock ("fclk")
 * with a programmable extra divisor.
 *
 * The following code goes through the clock sources, and calculates the
 * baud clocks (and the resultant actual baud rates) and then tries to
 * pick the closest one and select that.
 *
 */

#define MAX_CLK_NAME_LENGTH 15

static inline int s3c24xx_serial_getsource(struct uart_port *port)
{
        struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
        unsigned int ucon;

        if (info->num_clks == 1)
                return 0;

        ucon = rd_regl(port, S3C2410_UCON);
        ucon &= info->clksel_mask;
        return ucon >> info->clksel_shift;
}

static void s3c24xx_serial_setsource(struct uart_port *port,
                        unsigned int clk_sel)
{
        struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
        unsigned int ucon;

        if (info->num_clks == 1)
                return;

        ucon = rd_regl(port, S3C2410_UCON);
        if ((ucon & info->clksel_mask) >> info->clksel_shift == clk_sel)
                return;

        ucon &= ~info->clksel_mask;
        ucon |= clk_sel << info->clksel_shift;
        wr_regl(port, S3C2410_UCON, ucon);
}

static unsigned int s3c24xx_serial_getclk(struct s3c24xx_uart_port *ourport,
                        unsigned int req_baud, struct clk **best_clk,
                        unsigned int *clk_num)
{
        struct s3c24xx_uart_info *info = ourport->info;
        struct clk *clk;
        unsigned long rate;
        unsigned int cnt, baud, quot, best_quot = 0;
        char clkname[MAX_CLK_NAME_LENGTH];
        int calc_deviation, deviation = (1 << 30) - 1;

        for (cnt = 0; cnt < info->num_clks; cnt++) {
                /* Keep selected clock if provided */
                if (ourport->cfg->clk_sel &&
                        !(ourport->cfg->clk_sel & (1 << cnt)))
                        continue;

                sprintf(clkname, "clk_uart_baud%d", cnt);
                clk = clk_get(ourport->port.dev, clkname);
                if (IS_ERR(clk))
                        continue;

                rate = clk_get_rate(clk);
                if (!rate)
                        continue;

                if (ourport->info->has_divslot) {
                        unsigned long div = rate / req_baud;

                        /* The UDIVSLOT register on the newer UARTs allows us to
                         * get a divisor adjustment of 1/16th on the baud clock.
                         *
                         * We don't keep the UDIVSLOT value (the 16ths we
                         * calculated by not multiplying the baud by 16) as it
                         * is easy enough to recalculate.
                         */

                        quot = div / 16;
                        baud = rate / div;
                } else {
                        quot = (rate + (8 * req_baud)) / (16 * req_baud);
                        baud = rate / (quot * 16);
                }
                quot--;

                calc_deviation = req_baud - baud;
                if (calc_deviation < 0)
                        calc_deviation = -calc_deviation;

                if (calc_deviation < deviation) {
                        *best_clk = clk;
                        best_quot = quot;
                        *clk_num = cnt;
                        deviation = calc_deviation;
                }
        }

        return best_quot;
}

/* udivslot_table[]
 *
 * This table takes the fractional value of the baud divisor and gives
 * the recommended setting for the UDIVSLOT register.
 */
static u16 udivslot_table[16] = {
        [0] = 0x0000,
        [1] = 0x0080,
        [2] = 0x0808,
        [3] = 0x0888,
        [4] = 0x2222,
        [5] = 0x4924,
        [6] = 0x4A52,
        [7] = 0x54AA,
        [8] = 0x5555,
        [9] = 0xD555,
        [10] = 0xD5D5,
        [11] = 0xDDD5,
        [12] = 0xDDDD,
        [13] = 0xDFDD,
        [14] = 0xDFDF,
        [15] = 0xFFDF,
};

static void s3c24xx_serial_set_termios(struct uart_port *port,
                                       struct ktermios *termios,
                                       struct ktermios *old)
{
        struct s3c2410_uartcfg *cfg = s3c24xx_port_to_cfg(port);
        struct s3c24xx_uart_port *ourport = to_ourport(port);
        struct clk *clk = ERR_PTR(-EINVAL);
        unsigned long flags;
        unsigned int baud, quot, clk_sel = 0;
        unsigned int ulcon;
        unsigned int umcon;
        unsigned int udivslot = 0;

        /*
         * We don't support modem control lines.
         */
        termios->c_cflag &= ~(HUPCL | CMSPAR);
        termios->c_cflag |= CLOCAL;

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

        baud = uart_get_baud_rate(port, termios, old, 0, 3000000);
        quot = s3c24xx_serial_getclk(ourport, baud, &clk, &clk_sel);
        if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
                quot = port->custom_divisor;
        if (IS_ERR(clk))
                return;

        /* check to see if we need  to change clock source */

        if (ourport->baudclk != clk) {
                clk_prepare_enable(clk);

                s3c24xx_serial_setsource(port, clk_sel);

                if (!IS_ERR(ourport->baudclk)) {
                        clk_disable_unprepare(ourport->baudclk);
                        ourport->baudclk = ERR_PTR(-EINVAL);
                }

                ourport->baudclk = clk;
                ourport->baudclk_rate = clk ? clk_get_rate(clk) : 0;
        }

        if (ourport->info->has_divslot) {
                unsigned int div = ourport->baudclk_rate / baud;

                if (cfg->has_fracval) {
                        udivslot = (div & 15);
                        dev_dbg(port->dev, "fracval = %04x\n", udivslot);
                } else {
                        udivslot = udivslot_table[div & 15];
                        dev_dbg(port->dev, "udivslot = %04x (div %d)\n",
                                udivslot, div & 15);
                }
        }

        switch (termios->c_cflag & CSIZE) {
        case CS5:
                dev_dbg(port->dev, "config: 5bits/char\n");
                ulcon = S3C2410_LCON_CS5;
                break;
        case CS6:
                dev_dbg(port->dev, "config: 6bits/char\n");
                ulcon = S3C2410_LCON_CS6;
                break;
        case CS7:
                dev_dbg(port->dev, "config: 7bits/char\n");
                ulcon = S3C2410_LCON_CS7;
                break;
        case CS8:
        default:
                dev_dbg(port->dev, "config: 8bits/char\n");
                ulcon = S3C2410_LCON_CS8;
                break;
        }

        /* preserve original lcon IR settings */
        ulcon |= (cfg->ulcon & S3C2410_LCON_IRM);

        if (termios->c_cflag & CSTOPB)
                ulcon |= S3C2410_LCON_STOPB;

        if (termios->c_cflag & PARENB) {
                if (termios->c_cflag & PARODD)
                        ulcon |= S3C2410_LCON_PODD;
                else
                        ulcon |= S3C2410_LCON_PEVEN;
        } else {
                ulcon |= S3C2410_LCON_PNONE;
        }

        spin_lock_irqsave(&port->lock, flags);

        dev_dbg(port->dev,
                "setting ulcon to %08x, brddiv to %d, udivslot %08x\n",
                ulcon, quot, udivslot);

        wr_regl(port, S3C2410_ULCON, ulcon);
        wr_regl(port, S3C2410_UBRDIV, quot);

        port->status &= ~UPSTAT_AUTOCTS;

        umcon = rd_regl(port, S3C2410_UMCON);
        if (termios->c_cflag & CRTSCTS) {
                umcon |= S3C2410_UMCOM_AFC;
                /* Disable RTS when RX FIFO contains 63 bytes */
                umcon &= ~S3C2412_UMCON_AFC_8;
                port->status = UPSTAT_AUTOCTS;
        } else {
                umcon &= ~S3C2410_UMCOM_AFC;
        }
        wr_regl(port, S3C2410_UMCON, umcon);

        if (ourport->info->has_divslot)
                wr_regl(port, S3C2443_DIVSLOT, udivslot);

        dev_dbg(port->dev,
                "uart: ulcon = 0x%08x, ucon = 0x%08x, ufcon = 0x%08x\n",
                rd_regl(port, S3C2410_ULCON),
                rd_regl(port, S3C2410_UCON),
                rd_regl(port, S3C2410_UFCON));

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

        /*
         * Which character status flags are we interested in?
         */
        port->read_status_mask = S3C2410_UERSTAT_OVERRUN;
        if (termios->c_iflag & INPCK)
                port->read_status_mask |= S3C2410_UERSTAT_FRAME |
                        S3C2410_UERSTAT_PARITY;
        /*
         * Which character status flags should we ignore?
         */
        port->ignore_status_mask = 0;
        if (termios->c_iflag & IGNPAR)
                port->ignore_status_mask |= S3C2410_UERSTAT_OVERRUN;
        if (termios->c_iflag & IGNBRK && termios->c_iflag & IGNPAR)
                port->ignore_status_mask |= S3C2410_UERSTAT_FRAME;

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

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

static const char *s3c24xx_serial_type(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);

        switch (ourport->info->type) {
        case TYPE_S3C24XX:
                return "S3C24XX";
        case TYPE_S3C6400:
                return "S3C6400/10";
        case TYPE_APPLE_S5L:
                return "APPLE S5L";
        default:
                return NULL;
        }
}

static void s3c24xx_serial_config_port(struct uart_port *port, int flags)
{
        struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);

        if (flags & UART_CONFIG_TYPE)
                port->type = info->port_type;
}

/*
 * verify the new serial_struct (for TIOCSSERIAL).
 */
static int
s3c24xx_serial_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);

        if (ser->type != PORT_UNKNOWN && ser->type != info->port_type)
                return -EINVAL;

        return 0;
}

#ifdef CONFIG_SERIAL_SAMSUNG_CONSOLE

static struct console s3c24xx_serial_console;

static int __init s3c24xx_serial_console_init(void)
{
        register_console(&s3c24xx_serial_console);
        return 0;
}
console_initcall(s3c24xx_serial_console_init);

#define S3C24XX_SERIAL_CONSOLE &s3c24xx_serial_console
#else
#define S3C24XX_SERIAL_CONSOLE NULL
#endif

#if defined(CONFIG_SERIAL_SAMSUNG_CONSOLE) && defined(CONFIG_CONSOLE_POLL)
static int s3c24xx_serial_get_poll_char(struct uart_port *port);
static void s3c24xx_serial_put_poll_char(struct uart_port *port,
                         unsigned char c);
#endif

static const struct uart_ops s3c24xx_serial_ops = {
        .pm             = s3c24xx_serial_pm,
        .tx_empty       = s3c24xx_serial_tx_empty,
        .get_mctrl      = s3c24xx_serial_get_mctrl,
        .set_mctrl      = s3c24xx_serial_set_mctrl,
        .stop_tx        = s3c24xx_serial_stop_tx,
        .start_tx       = s3c24xx_serial_start_tx,
        .stop_rx        = s3c24xx_serial_stop_rx,
        .break_ctl      = s3c24xx_serial_break_ctl,
        .startup        = s3c24xx_serial_startup,
        .shutdown       = s3c24xx_serial_shutdown,
        .set_termios    = s3c24xx_serial_set_termios,
        .type           = s3c24xx_serial_type,
        .config_port    = s3c24xx_serial_config_port,
        .verify_port    = s3c24xx_serial_verify_port,
#if defined(CONFIG_SERIAL_SAMSUNG_CONSOLE) && defined(CONFIG_CONSOLE_POLL)
        .poll_get_char = s3c24xx_serial_get_poll_char,
        .poll_put_char = s3c24xx_serial_put_poll_char,
#endif
};

static const struct uart_ops s3c64xx_serial_ops = {
        .pm             = s3c24xx_serial_pm,
        .tx_empty       = s3c24xx_serial_tx_empty,
        .get_mctrl      = s3c24xx_serial_get_mctrl,
        .set_mctrl      = s3c24xx_serial_set_mctrl,
        .stop_tx        = s3c24xx_serial_stop_tx,
        .start_tx       = s3c24xx_serial_start_tx,
        .stop_rx        = s3c24xx_serial_stop_rx,
        .break_ctl      = s3c24xx_serial_break_ctl,
        .startup        = s3c64xx_serial_startup,
        .shutdown       = s3c64xx_serial_shutdown,
        .set_termios    = s3c24xx_serial_set_termios,
        .type           = s3c24xx_serial_type,
        .config_port    = s3c24xx_serial_config_port,
        .verify_port    = s3c24xx_serial_verify_port,
#if defined(CONFIG_SERIAL_SAMSUNG_CONSOLE) && defined(CONFIG_CONSOLE_POLL)
        .poll_get_char = s3c24xx_serial_get_poll_char,
        .poll_put_char = s3c24xx_serial_put_poll_char,
#endif
};

static const struct uart_ops apple_s5l_serial_ops = {
        .pm             = s3c24xx_serial_pm,
        .tx_empty       = s3c24xx_serial_tx_empty,
        .get_mctrl      = s3c24xx_serial_get_mctrl,
        .set_mctrl      = s3c24xx_serial_set_mctrl,
        .stop_tx        = s3c24xx_serial_stop_tx,
        .start_tx       = s3c24xx_serial_start_tx,
        .stop_rx        = s3c24xx_serial_stop_rx,
        .break_ctl      = s3c24xx_serial_break_ctl,
        .startup        = apple_s5l_serial_startup,
        .shutdown       = apple_s5l_serial_shutdown,
        .set_termios    = s3c24xx_serial_set_termios,
        .type           = s3c24xx_serial_type,
        .config_port    = s3c24xx_serial_config_port,
        .verify_port    = s3c24xx_serial_verify_port,
#if defined(CONFIG_SERIAL_SAMSUNG_CONSOLE) && defined(CONFIG_CONSOLE_POLL)
        .poll_get_char = s3c24xx_serial_get_poll_char,
        .poll_put_char = s3c24xx_serial_put_poll_char,
#endif
};

static struct uart_driver s3c24xx_uart_drv = {
        .owner          = THIS_MODULE,
        .driver_name    = "s3c2410_serial",
        .nr             = CONFIG_SERIAL_SAMSUNG_UARTS,
        .cons           = S3C24XX_SERIAL_CONSOLE,
        .dev_name       = S3C24XX_SERIAL_NAME,
        .major          = S3C24XX_SERIAL_MAJOR,
        .minor          = S3C24XX_SERIAL_MINOR,
};

#define __PORT_LOCK_UNLOCKED(i) \
        __SPIN_LOCK_UNLOCKED(s3c24xx_serial_ports[i].port.lock)
static struct s3c24xx_uart_port
s3c24xx_serial_ports[CONFIG_SERIAL_SAMSUNG_UARTS] = {
        [0] = {
                .port = {
                        .lock           = __PORT_LOCK_UNLOCKED(0),
                        .iotype         = UPIO_MEM,
                        .uartclk        = 0,
                        .fifosize       = 16,
                        .ops            = &s3c24xx_serial_ops,
                        .flags          = UPF_BOOT_AUTOCONF,
                        .line           = 0,
                }
        },
        [1] = {
                .port = {
                        .lock           = __PORT_LOCK_UNLOCKED(1),
                        .iotype         = UPIO_MEM,
                        .uartclk        = 0,
                        .fifosize       = 16,
                        .ops            = &s3c24xx_serial_ops,
                        .flags          = UPF_BOOT_AUTOCONF,
                        .line           = 1,
                }
        },
#if CONFIG_SERIAL_SAMSUNG_UARTS > 2
        [2] = {
                .port = {
                        .lock           = __PORT_LOCK_UNLOCKED(2),
                        .iotype         = UPIO_MEM,
                        .uartclk        = 0,
                        .fifosize       = 16,
                        .ops            = &s3c24xx_serial_ops,
                        .flags          = UPF_BOOT_AUTOCONF,
                        .line           = 2,
                }
        },
#endif
#if CONFIG_SERIAL_SAMSUNG_UARTS > 3
        [3] = {
                .port = {
                        .lock           = __PORT_LOCK_UNLOCKED(3),
                        .iotype         = UPIO_MEM,
                        .uartclk        = 0,
                        .fifosize       = 16,
                        .ops            = &s3c24xx_serial_ops,
                        .flags          = UPF_BOOT_AUTOCONF,
                        .line           = 3,
                }
        }
#endif
};
#undef __PORT_LOCK_UNLOCKED

/* s3c24xx_serial_resetport
 *
 * reset the fifos and other the settings.
 */

static void s3c24xx_serial_resetport(struct uart_port *port,
                                   struct s3c2410_uartcfg *cfg)
{
        struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
        unsigned long ucon = rd_regl(port, S3C2410_UCON);

        ucon &= (info->clksel_mask | info->ucon_mask);
        wr_regl(port, S3C2410_UCON, ucon | cfg->ucon);

        /* reset both fifos */
        wr_regl(port, S3C2410_UFCON, cfg->ufcon | S3C2410_UFCON_RESETBOTH);
        wr_regl(port, S3C2410_UFCON, cfg->ufcon);

        /* some delay is required after fifo reset */
        udelay(1);
}

#ifdef CONFIG_ARM_S3C24XX_CPUFREQ

static int s3c24xx_serial_cpufreq_transition(struct notifier_block *nb,
                                             unsigned long val, void *data)
{
        struct s3c24xx_uart_port *port;
        struct uart_port *uport;

        port = container_of(nb, struct s3c24xx_uart_port, freq_transition);
        uport = &port->port;

        /* check to see if port is enabled */

        if (port->pm_level != 0)
                return 0;

        /* try and work out if the baudrate is changing, we can detect
         * a change in rate, but we do not have support for detecting
         * a disturbance in the clock-rate over the change.
         */

        if (IS_ERR(port->baudclk))
                goto exit;

        if (port->baudclk_rate == clk_get_rate(port->baudclk))
                goto exit;

        if (val == CPUFREQ_PRECHANGE) {
                /* we should really shut the port down whilst the
                 * frequency change is in progress.
                 */

        } else if (val == CPUFREQ_POSTCHANGE) {
                struct ktermios *termios;
                struct tty_struct *tty;

                if (uport->state == NULL)
                        goto exit;

                tty = uport->state->port.tty;

                if (tty == NULL)
                        goto exit;

                termios = &tty->termios;

                if (termios == NULL) {
                        dev_warn(uport->dev, "%s: no termios?\n", __func__);
                        goto exit;
                }

                s3c24xx_serial_set_termios(uport, termios, NULL);
        }

exit:
        return 0;
}

static inline int
s3c24xx_serial_cpufreq_register(struct s3c24xx_uart_port *port)
{
        port->freq_transition.notifier_call = s3c24xx_serial_cpufreq_transition;

        return cpufreq_register_notifier(&port->freq_transition,
                                         CPUFREQ_TRANSITION_NOTIFIER);
}

static inline void
s3c24xx_serial_cpufreq_deregister(struct s3c24xx_uart_port *port)
{
        cpufreq_unregister_notifier(&port->freq_transition,
                                    CPUFREQ_TRANSITION_NOTIFIER);
}

#else
static inline int
s3c24xx_serial_cpufreq_register(struct s3c24xx_uart_port *port)
{
        return 0;
}

static inline void
s3c24xx_serial_cpufreq_deregister(struct s3c24xx_uart_port *port)
{
}
#endif

static int s3c24xx_serial_enable_baudclk(struct s3c24xx_uart_port *ourport)
{
        struct device *dev = ourport->port.dev;

        struct s3c24xx_uart_info *info = ourport->info;
        char clk_name[MAX_CLK_NAME_LENGTH];
        unsigned int clk_sel;
        struct clk *clk;
        int clk_num;
        int ret;

        clk_sel = ourport->cfg->clk_sel ? : info->def_clk_sel;
        for (clk_num = 0; clk_num < info->num_clks; clk_num++) {
                if (!(clk_sel & (1 << clk_num)))
                        continue;

                sprintf(clk_name, "clk_uart_baud%d", clk_num);
                clk = clk_get(dev, clk_name);
                if (IS_ERR(clk))
                        continue;

                ret = clk_prepare_enable(clk);
                if (ret) {
                        clk_put(clk);
                        continue;
                }

                ourport->baudclk = clk;
                ourport->baudclk_rate = clk_get_rate(clk);
                s3c24xx_serial_setsource(&ourport->port, clk_num);

                return 0;
        }

        return -EINVAL;
}

/* s3c24xx_serial_init_port
 *
 * initialise a single serial port from the platform device given
 */

static int s3c24xx_serial_init_port(struct s3c24xx_uart_port *ourport,
                                    struct platform_device *platdev)
{
        struct uart_port *port = &ourport->port;
        struct s3c2410_uartcfg *cfg = ourport->cfg;
        struct resource *res;
        int ret;

        if (platdev == NULL)
                return -ENODEV;

        if (port->mapbase != 0)
                return -EINVAL;

        /* setup info for port */
        port->dev       = &platdev->dev;

        port->uartclk = 1;

        if (cfg->uart_flags & UPF_CONS_FLOW) {
                dev_dbg(port->dev, "enabling flow control\n");
                port->flags |= UPF_CONS_FLOW;
        }

        /* sort our the physical and virtual addresses for each UART */

        res = platform_get_resource(platdev, IORESOURCE_MEM, 0);
        if (res == NULL) {
                dev_err(port->dev, "failed to find memory resource for uart\n");
                return -EINVAL;
        }

        dev_dbg(port->dev, "resource %pR)\n", res);

        port->membase = devm_ioremap_resource(port->dev, res);
        if (IS_ERR(port->membase)) {
                dev_err(port->dev, "failed to remap controller address\n");
                return -EBUSY;
        }

        port->mapbase = res->start;
        ret = platform_get_irq(platdev, 0);
        if (ret < 0) {
                port->irq = 0;
        } else {
                port->irq = ret;
                ourport->rx_irq = ret;
                ourport->tx_irq = ret + 1;
        }

        switch (ourport->info->type) {
        case TYPE_S3C24XX:
                ret = platform_get_irq(platdev, 1);
                if (ret > 0)
                        ourport->tx_irq = ret;
                break;
        default:
                break;
        }

        /*
         * DMA is currently supported only on DT platforms, if DMA properties
         * are specified.
         */
        if (platdev->dev.of_node && of_find_property(platdev->dev.of_node,
                                                     "dmas", NULL)) {
                ourport->dma = devm_kzalloc(port->dev,
                                            sizeof(*ourport->dma),
                                            GFP_KERNEL);
                if (!ourport->dma) {
                        ret = -ENOMEM;
                        goto err;
                }
        }

        ourport->clk    = clk_get(&platdev->dev, "uart");
        if (IS_ERR(ourport->clk)) {
                pr_err("%s: Controller clock not found\n",
                                dev_name(&platdev->dev));
                ret = PTR_ERR(ourport->clk);
                goto err;
        }

        ret = clk_prepare_enable(ourport->clk);
        if (ret) {
                pr_err("uart: clock failed to prepare+enable: %d\n", ret);
                clk_put(ourport->clk);
                goto err;
        }

        ret = s3c24xx_serial_enable_baudclk(ourport);
        if (ret)
                pr_warn("uart: failed to enable baudclk\n");

        exynos_usi_init(port);

        /* Keep all interrupts masked and cleared */
        switch (ourport->info->type) {
        case TYPE_S3C6400:
                wr_regl(port, S3C64XX_UINTM, 0xf);
                wr_regl(port, S3C64XX_UINTP, 0xf);
                wr_regl(port, S3C64XX_UINTSP, 0xf);
                break;
        case TYPE_APPLE_S5L: {
                unsigned int ucon;

                ucon = rd_regl(port, S3C2410_UCON);
                ucon &= ~(APPLE_S5L_UCON_TXTHRESH_ENA_MSK |
                        APPLE_S5L_UCON_RXTHRESH_ENA_MSK |
                        APPLE_S5L_UCON_RXTO_ENA_MSK);
                wr_regl(port, S3C2410_UCON, ucon);

                wr_regl(port, S3C2410_UTRSTAT, APPLE_S5L_UTRSTAT_ALL_FLAGS);
                break;
        }
        default:
                break;
        }

        dev_dbg(port->dev, "port: map=%pa, mem=%p, irq=%d (%d,%d), clock=%u\n",
                &port->mapbase, port->membase, port->irq,
                ourport->rx_irq, ourport->tx_irq, port->uartclk);

        /* reset the fifos (and setup the uart) */
        s3c24xx_serial_resetport(port, cfg);

        return 0;

err:
        port->mapbase = 0;
        return ret;
}

/* Device driver serial port probe */

#ifdef CONFIG_OF
static const struct of_device_id s3c24xx_uart_dt_match[];
#endif

static int probe_index;

static inline struct s3c24xx_serial_drv_data *
s3c24xx_get_driver_data(struct platform_device *pdev)
{
#ifdef CONFIG_OF
        if (pdev->dev.of_node) {
                const struct of_device_id *match;

                match = of_match_node(s3c24xx_uart_dt_match, pdev->dev.of_node);
                return (struct s3c24xx_serial_drv_data *)match->data;
        }
#endif
        return (struct s3c24xx_serial_drv_data *)
                        platform_get_device_id(pdev)->driver_data;
}

static int s3c24xx_serial_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct s3c24xx_uart_port *ourport;
        int index = probe_index;
        int ret, prop = 0;

        if (np) {
                ret = of_alias_get_id(np, "serial");
                if (ret >= 0)
                        index = ret;
        }

        if (index >= ARRAY_SIZE(s3c24xx_serial_ports)) {
                dev_err(&pdev->dev, "serial%d out of range\n", index);
                return -EINVAL;
        }
        ourport = &s3c24xx_serial_ports[index];

        ourport->drv_data = s3c24xx_get_driver_data(pdev);
        if (!ourport->drv_data) {
                dev_err(&pdev->dev, "could not find driver data\n");
                return -ENODEV;
        }

        ourport->baudclk = ERR_PTR(-EINVAL);
        ourport->info = ourport->drv_data->info;
        ourport->cfg = (dev_get_platdata(&pdev->dev)) ?
                        dev_get_platdata(&pdev->dev) :
                        ourport->drv_data->def_cfg;

        switch (ourport->info->type) {
        case TYPE_S3C24XX:
                ourport->port.ops = &s3c24xx_serial_ops;
                break;
        case TYPE_S3C6400:
                ourport->port.ops = &s3c64xx_serial_ops;
                break;
        case TYPE_APPLE_S5L:
                ourport->port.ops = &apple_s5l_serial_ops;
                break;
        }

        if (np) {
                of_property_read_u32(np,
                        "samsung,uart-fifosize", &ourport->port.fifosize);

                if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
                        switch (prop) {
                        case 1:
                                ourport->port.iotype = UPIO_MEM;
                                break;
                        case 4:
                                ourport->port.iotype = UPIO_MEM32;
                                break;
                        default:
                                dev_warn(&pdev->dev, "unsupported reg-io-width (%d)\n",
                                                prop);
                                return -EINVAL;
                        }
                }
        }

        if (ourport->drv_data->fifosize[index])
                ourport->port.fifosize = ourport->drv_data->fifosize[index];
        else if (ourport->info->fifosize)
                ourport->port.fifosize = ourport->info->fifosize;
        ourport->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_SAMSUNG_CONSOLE);

        /*
         * DMA transfers must be aligned at least to cache line size,
         * so find minimal transfer size suitable for DMA mode
         */
        ourport->min_dma_size = max_t(int, ourport->port.fifosize,
                                    dma_get_cache_alignment());

        dev_dbg(&pdev->dev, "%s: initialising port %p...\n", __func__, ourport);

        ret = s3c24xx_serial_init_port(ourport, pdev);
        if (ret < 0)
                return ret;

        if (!s3c24xx_uart_drv.state) {
                ret = uart_register_driver(&s3c24xx_uart_drv);
                if (ret < 0) {
                        pr_err("Failed to register Samsung UART driver\n");
                        return ret;
                }
        }

        dev_dbg(&pdev->dev, "%s: adding port\n", __func__);
        uart_add_one_port(&s3c24xx_uart_drv, &ourport->port);
        platform_set_drvdata(pdev, &ourport->port);

        /*
         * Deactivate the clock enabled in s3c24xx_serial_init_port here,
         * so that a potential re-enablement through the pm-callback overlaps
         * and keeps the clock enabled in this case.
         */
        clk_disable_unprepare(ourport->clk);
        if (!IS_ERR(ourport->baudclk))
                clk_disable_unprepare(ourport->baudclk);

        ret = s3c24xx_serial_cpufreq_register(ourport);
        if (ret < 0)
                dev_err(&pdev->dev, "failed to add cpufreq notifier\n");

        probe_index++;

        return 0;
}

static int s3c24xx_serial_remove(struct platform_device *dev)
{
        struct uart_port *port = s3c24xx_dev_to_port(&dev->dev);

        if (port) {
                s3c24xx_serial_cpufreq_deregister(to_ourport(port));
                uart_remove_one_port(&s3c24xx_uart_drv, port);
        }

        uart_unregister_driver(&s3c24xx_uart_drv);

        return 0;
}

/* UART power management code */
#ifdef CONFIG_PM_SLEEP
static int s3c24xx_serial_suspend(struct device *dev)
{
        struct uart_port *port = s3c24xx_dev_to_port(dev);

        if (port)
                uart_suspend_port(&s3c24xx_uart_drv, port);

        return 0;
}

static int s3c24xx_serial_resume(struct device *dev)
{
        struct uart_port *port = s3c24xx_dev_to_port(dev);
        struct s3c24xx_uart_port *ourport = to_ourport(port);

        if (port) {
                clk_prepare_enable(ourport->clk);
                if (!IS_ERR(ourport->baudclk))
                        clk_prepare_enable(ourport->baudclk);
                s3c24xx_serial_resetport(port, s3c24xx_port_to_cfg(port));
                if (!IS_ERR(ourport->baudclk))
                        clk_disable_unprepare(ourport->baudclk);
                clk_disable_unprepare(ourport->clk);

                uart_resume_port(&s3c24xx_uart_drv, port);
        }

        return 0;
}

static int s3c24xx_serial_resume_noirq(struct device *dev)
{
        struct uart_port *port = s3c24xx_dev_to_port(dev);
        struct s3c24xx_uart_port *ourport = to_ourport(port);

        if (port) {
                /* restore IRQ mask */
                switch (ourport->info->type) {
                case TYPE_S3C6400: {
                        unsigned int uintm = 0xf;

                        if (ourport->tx_enabled)
                                uintm &= ~S3C64XX_UINTM_TXD_MSK;
                        if (ourport->rx_enabled)
                                uintm &= ~S3C64XX_UINTM_RXD_MSK;
                        clk_prepare_enable(ourport->clk);
                        if (!IS_ERR(ourport->baudclk))
                                clk_prepare_enable(ourport->baudclk);
                        wr_regl(port, S3C64XX_UINTM, uintm);
                        if (!IS_ERR(ourport->baudclk))
                                clk_disable_unprepare(ourport->baudclk);
                        clk_disable_unprepare(ourport->clk);
                        break;
                }
                case TYPE_APPLE_S5L: {
                        unsigned int ucon;
                        int ret;

                        ret = clk_prepare_enable(ourport->clk);
                        if (ret) {
                                dev_err(dev, "clk_enable clk failed: %d\n", ret);
                                return ret;
                        }
                        if (!IS_ERR(ourport->baudclk)) {
                                ret = clk_prepare_enable(ourport->baudclk);
                                if (ret) {
                                        dev_err(dev, "clk_enable baudclk failed: %d\n", ret);
                                        clk_disable_unprepare(ourport->clk);
                                        return ret;
                                }
                        }

                        ucon = rd_regl(port, S3C2410_UCON);

                        ucon &= ~(APPLE_S5L_UCON_TXTHRESH_ENA_MSK |
                                  APPLE_S5L_UCON_RXTHRESH_ENA_MSK |
                                  APPLE_S5L_UCON_RXTO_ENA_MSK);

                        if (ourport->tx_enabled)
                                ucon |= APPLE_S5L_UCON_TXTHRESH_ENA_MSK;
                        if (ourport->rx_enabled)
                                ucon |= APPLE_S5L_UCON_RXTHRESH_ENA_MSK |
                                        APPLE_S5L_UCON_RXTO_ENA_MSK;

                        wr_regl(port, S3C2410_UCON, ucon);

                        if (!IS_ERR(ourport->baudclk))
                                clk_disable_unprepare(ourport->baudclk);
                        clk_disable_unprepare(ourport->clk);
                        break;
                }
                default:
                        break;
                }
        }

        return 0;
}

static const struct dev_pm_ops s3c24xx_serial_pm_ops = {
        .suspend = s3c24xx_serial_suspend,
        .resume = s3c24xx_serial_resume,
        .resume_noirq = s3c24xx_serial_resume_noirq,
};
#define SERIAL_SAMSUNG_PM_OPS   (&s3c24xx_serial_pm_ops)

#else /* !CONFIG_PM_SLEEP */

#define SERIAL_SAMSUNG_PM_OPS   NULL
#endif /* CONFIG_PM_SLEEP */

/* Console code */

#ifdef CONFIG_SERIAL_SAMSUNG_CONSOLE

static struct uart_port *cons_uart;

static int
s3c24xx_serial_console_txrdy(struct uart_port *port, unsigned int ufcon)
{
        struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
        unsigned long ufstat, utrstat;

        if (ufcon & S3C2410_UFCON_FIFOMODE) {
                /* fifo mode - check amount of data in fifo registers... */

                ufstat = rd_regl(port, S3C2410_UFSTAT);
                return (ufstat & info->tx_fifofull) ? 0 : 1;
        }

        /* in non-fifo mode, we go and use the tx buffer empty */

        utrstat = rd_regl(port, S3C2410_UTRSTAT);
        return (utrstat & S3C2410_UTRSTAT_TXE) ? 1 : 0;
}

static bool
s3c24xx_port_configured(unsigned int ucon)
{
        /* consider the serial port configured if the tx/rx mode set */
        return (ucon & 0xf) != 0;
}

#ifdef CONFIG_CONSOLE_POLL
/*
 * Console polling routines for writing and reading from the uart while
 * in an interrupt or debug context.
 */

static int s3c24xx_serial_get_poll_char(struct uart_port *port)
{
        struct s3c24xx_uart_port *ourport = to_ourport(port);
        unsigned int ufstat;

        ufstat = rd_regl(port, S3C2410_UFSTAT);
        if (s3c24xx_serial_rx_fifocnt(ourport, ufstat) == 0)
                return NO_POLL_CHAR;

        return rd_reg(port, S3C2410_URXH);
}

static void s3c24xx_serial_put_poll_char(struct uart_port *port,
                unsigned char c)
{
        unsigned int ufcon = rd_regl(port, S3C2410_UFCON);
        unsigned int ucon = rd_regl(port, S3C2410_UCON);

        /* not possible to xmit on unconfigured port */
        if (!s3c24xx_port_configured(ucon))
                return;

        while (!s3c24xx_serial_console_txrdy(port, ufcon))
                cpu_relax();
        wr_reg(port, S3C2410_UTXH, c);
}

#endif /* CONFIG_CONSOLE_POLL */

static void
s3c24xx_serial_console_putchar(struct uart_port *port, int ch)
{
        unsigned int ufcon = rd_regl(port, S3C2410_UFCON);

        while (!s3c24xx_serial_console_txrdy(port, ufcon))
                cpu_relax();
        wr_reg(port, S3C2410_UTXH, ch);
}

static void
s3c24xx_serial_console_write(struct console *co, const char *s,
                             unsigned int count)
{
        unsigned int ucon = rd_regl(cons_uart, S3C2410_UCON);

        /* not possible to xmit on unconfigured port */
        if (!s3c24xx_port_configured(ucon))
                return;

        uart_console_write(cons_uart, s, count, s3c24xx_serial_console_putchar);
}

static void __init
s3c24xx_serial_get_options(struct uart_port *port, int *baud,
                           int *parity, int *bits)
{
        struct clk *clk;
        unsigned int ulcon;
        unsigned int ucon;
        unsigned int ubrdiv;
        unsigned long rate;
        unsigned int clk_sel;
        char clk_name[MAX_CLK_NAME_LENGTH];

        ulcon  = rd_regl(port, S3C2410_ULCON);
        ucon   = rd_regl(port, S3C2410_UCON);
        ubrdiv = rd_regl(port, S3C2410_UBRDIV);

        if (s3c24xx_port_configured(ucon)) {
                switch (ulcon & S3C2410_LCON_CSMASK) {
                case S3C2410_LCON_CS5:
                        *bits = 5;
                        break;
                case S3C2410_LCON_CS6:
                        *bits = 6;
                        break;
                case S3C2410_LCON_CS7:
                        *bits = 7;
                        break;
                case S3C2410_LCON_CS8:
                default:
                        *bits = 8;
                        break;
                }

                switch (ulcon & S3C2410_LCON_PMASK) {
                case S3C2410_LCON_PEVEN:
                        *parity = 'e';
                        break;

                case S3C2410_LCON_PODD:
                        *parity = 'o';
                        break;

                case S3C2410_LCON_PNONE:
                default:
                        *parity = 'n';
                }

                /* now calculate the baud rate */

                clk_sel = s3c24xx_serial_getsource(port);
                sprintf(clk_name, "clk_uart_baud%d", clk_sel);

                clk = clk_get(port->dev, clk_name);
                if (!IS_ERR(clk))
                        rate = clk_get_rate(clk);
                else
                        rate = 1;

                *baud = rate / (16 * (ubrdiv + 1));
                dev_dbg(port->dev, "calculated baud %d\n", *baud);
        }
}

static int __init
s3c24xx_serial_console_setup(struct console *co, char *options)
{
        struct uart_port *port;
        int baud = 9600;
        int bits = 8;
        int parity = 'n';
        int flow = 'n';

        /* is this a valid port */

        if (co->index == -1 || co->index >= CONFIG_SERIAL_SAMSUNG_UARTS)
                co->index = 0;

        port = &s3c24xx_serial_ports[co->index].port;

        /* is the port configured? */

        if (port->mapbase == 0x0)
                return -ENODEV;

        cons_uart = port;

        /*
         * Check whether an invalid uart number has been specified, and
         * if so, search for the first available port that does have
         * console support.
         */
        if (options)
                uart_parse_options(options, &baud, &parity, &bits, &flow);
        else
                s3c24xx_serial_get_options(port, &baud, &parity, &bits);

        dev_dbg(port->dev, "baud %d\n", baud);

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

static struct console s3c24xx_serial_console = {
        .name           = S3C24XX_SERIAL_NAME,
        .device         = uart_console_device,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
        .write          = s3c24xx_serial_console_write,
        .setup          = s3c24xx_serial_console_setup,
        .data           = &s3c24xx_uart_drv,
};
#endif /* CONFIG_SERIAL_SAMSUNG_CONSOLE */

#ifdef CONFIG_CPU_S3C2410
static struct s3c24xx_serial_drv_data s3c2410_serial_drv_data = {
        .info = &(struct s3c24xx_uart_info) {
                .name           = "Samsung S3C2410 UART",
                .type           = TYPE_S3C24XX,
                .port_type      = PORT_S3C2410,
                .fifosize       = 16,
                .rx_fifomask    = S3C2410_UFSTAT_RXMASK,
                .rx_fifoshift   = S3C2410_UFSTAT_RXSHIFT,
                .rx_fifofull    = S3C2410_UFSTAT_RXFULL,
                .tx_fifofull    = S3C2410_UFSTAT_TXFULL,
                .tx_fifomask    = S3C2410_UFSTAT_TXMASK,
                .tx_fifoshift   = S3C2410_UFSTAT_TXSHIFT,
                .def_clk_sel    = S3C2410_UCON_CLKSEL0,
                .num_clks       = 2,
                .clksel_mask    = S3C2410_UCON_CLKMASK,
                .clksel_shift   = S3C2410_UCON_CLKSHIFT,
        },
        .def_cfg = &(struct s3c2410_uartcfg) {
                .ucon           = S3C2410_UCON_DEFAULT,
                .ufcon          = S3C2410_UFCON_DEFAULT,
        },
};
#define S3C2410_SERIAL_DRV_DATA ((kernel_ulong_t)&s3c2410_serial_drv_data)
#else
#define S3C2410_SERIAL_DRV_DATA (kernel_ulong_t)NULL
#endif

#ifdef CONFIG_CPU_S3C2412
static struct s3c24xx_serial_drv_data s3c2412_serial_drv_data = {
        .info = &(struct s3c24xx_uart_info) {
                .name           = "Samsung S3C2412 UART",
                .type           = TYPE_S3C24XX,
                .port_type      = PORT_S3C2412,
                .fifosize       = 64,
                .has_divslot    = 1,
                .rx_fifomask    = S3C2440_UFSTAT_RXMASK,
                .rx_fifoshift   = S3C2440_UFSTAT_RXSHIFT,
                .rx_fifofull    = S3C2440_UFSTAT_RXFULL,
                .tx_fifofull    = S3C2440_UFSTAT_TXFULL,
                .tx_fifomask    = S3C2440_UFSTAT_TXMASK,
                .tx_fifoshift   = S3C2440_UFSTAT_TXSHIFT,
                .def_clk_sel    = S3C2410_UCON_CLKSEL2,
                .num_clks       = 4,
                .clksel_mask    = S3C2412_UCON_CLKMASK,
                .clksel_shift   = S3C2412_UCON_CLKSHIFT,
        },
        .def_cfg = &(struct s3c2410_uartcfg) {
                .ucon           = S3C2410_UCON_DEFAULT,
                .ufcon          = S3C2410_UFCON_DEFAULT,
        },
};
#define S3C2412_SERIAL_DRV_DATA ((kernel_ulong_t)&s3c2412_serial_drv_data)
#else
#define S3C2412_SERIAL_DRV_DATA (kernel_ulong_t)NULL
#endif

#if defined(CONFIG_CPU_S3C2440) || defined(CONFIG_CPU_S3C2416) || \
        defined(CONFIG_CPU_S3C2443) || defined(CONFIG_CPU_S3C2442)
static struct s3c24xx_serial_drv_data s3c2440_serial_drv_data = {
        .info = &(struct s3c24xx_uart_info) {
                .name           = "Samsung S3C2440 UART",
                .type           = TYPE_S3C24XX,
                .port_type      = PORT_S3C2440,
                .fifosize       = 64,
                .has_divslot    = 1,
                .rx_fifomask    = S3C2440_UFSTAT_RXMASK,
                .rx_fifoshift   = S3C2440_UFSTAT_RXSHIFT,
                .rx_fifofull    = S3C2440_UFSTAT_RXFULL,
                .tx_fifofull    = S3C2440_UFSTAT_TXFULL,
                .tx_fifomask    = S3C2440_UFSTAT_TXMASK,
                .tx_fifoshift   = S3C2440_UFSTAT_TXSHIFT,
                .def_clk_sel    = S3C2410_UCON_CLKSEL2,
                .num_clks       = 4,
                .clksel_mask    = S3C2412_UCON_CLKMASK,
                .clksel_shift   = S3C2412_UCON_CLKSHIFT,
                .ucon_mask      = S3C2440_UCON0_DIVMASK,
        },
        .def_cfg = &(struct s3c2410_uartcfg) {
                .ucon           = S3C2410_UCON_DEFAULT,
                .ufcon          = S3C2410_UFCON_DEFAULT,
        },
};
#define S3C2440_SERIAL_DRV_DATA ((kernel_ulong_t)&s3c2440_serial_drv_data)
#else
#define S3C2440_SERIAL_DRV_DATA (kernel_ulong_t)NULL
#endif

#if defined(CONFIG_CPU_S3C6400) || defined(CONFIG_CPU_S3C6410)
static struct s3c24xx_serial_drv_data s3c6400_serial_drv_data = {
        .info = &(struct s3c24xx_uart_info) {
                .name           = "Samsung S3C6400 UART",
                .type           = TYPE_S3C6400,
                .port_type      = PORT_S3C6400,
                .fifosize       = 64,
                .has_divslot    = 1,
                .rx_fifomask    = S3C2440_UFSTAT_RXMASK,
                .rx_fifoshift   = S3C2440_UFSTAT_RXSHIFT,
                .rx_fifofull    = S3C2440_UFSTAT_RXFULL,
                .tx_fifofull    = S3C2440_UFSTAT_TXFULL,
                .tx_fifomask    = S3C2440_UFSTAT_TXMASK,
                .tx_fifoshift   = S3C2440_UFSTAT_TXSHIFT,
                .def_clk_sel    = S3C2410_UCON_CLKSEL2,
                .num_clks       = 4,
                .clksel_mask    = S3C6400_UCON_CLKMASK,
                .clksel_shift   = S3C6400_UCON_CLKSHIFT,
        },
        .def_cfg = &(struct s3c2410_uartcfg) {
                .ucon           = S3C2410_UCON_DEFAULT,
                .ufcon          = S3C2410_UFCON_DEFAULT,
        },
};
#define S3C6400_SERIAL_DRV_DATA ((kernel_ulong_t)&s3c6400_serial_drv_data)
#else
#define S3C6400_SERIAL_DRV_DATA (kernel_ulong_t)NULL
#endif

#ifdef CONFIG_CPU_S5PV210
static struct s3c24xx_serial_drv_data s5pv210_serial_drv_data = {
        .info = &(struct s3c24xx_uart_info) {
                .name           = "Samsung S5PV210 UART",
                .type           = TYPE_S3C6400,
                .port_type      = PORT_S3C6400,
                .has_divslot    = 1,
                .rx_fifomask    = S5PV210_UFSTAT_RXMASK,
                .rx_fifoshift   = S5PV210_UFSTAT_RXSHIFT,
                .rx_fifofull    = S5PV210_UFSTAT_RXFULL,
                .tx_fifofull    = S5PV210_UFSTAT_TXFULL,
                .tx_fifomask    = S5PV210_UFSTAT_TXMASK,
                .tx_fifoshift   = S5PV210_UFSTAT_TXSHIFT,
                .def_clk_sel    = S3C2410_UCON_CLKSEL0,
                .num_clks       = 2,
                .clksel_mask    = S5PV210_UCON_CLKMASK,
                .clksel_shift   = S5PV210_UCON_CLKSHIFT,
        },
        .def_cfg = &(struct s3c2410_uartcfg) {
                .ucon           = S5PV210_UCON_DEFAULT,
                .ufcon          = S5PV210_UFCON_DEFAULT,
        },
        .fifosize = { 256, 64, 16, 16 },
};
#define S5PV210_SERIAL_DRV_DATA ((kernel_ulong_t)&s5pv210_serial_drv_data)
#else
#define S5PV210_SERIAL_DRV_DATA (kernel_ulong_t)NULL
#endif

#if defined(CONFIG_ARCH_EXYNOS)
#define EXYNOS_COMMON_SERIAL_DRV_DATA_USI(_has_usi)             \
        .info = &(struct s3c24xx_uart_info) {                   \
                .name           = "Samsung Exynos UART",        \
                .type           = TYPE_S3C6400,                 \
                .has_usi        = _has_usi,                     \
                .port_type      = PORT_S3C6400,                 \
                .has_divslot    = 1,                            \
                .rx_fifomask    = S5PV210_UFSTAT_RXMASK,        \
                .rx_fifoshift   = S5PV210_UFSTAT_RXSHIFT,       \
                .rx_fifofull    = S5PV210_UFSTAT_RXFULL,        \
                .tx_fifofull    = S5PV210_UFSTAT_TXFULL,        \
                .tx_fifomask    = S5PV210_UFSTAT_TXMASK,        \
                .tx_fifoshift   = S5PV210_UFSTAT_TXSHIFT,       \
                .def_clk_sel    = S3C2410_UCON_CLKSEL0,         \
                .num_clks       = 1,                            \
                .clksel_mask    = 0,                            \
                .clksel_shift   = 0,                            \
        },                                                      \
        .def_cfg = &(struct s3c2410_uartcfg) {                  \
                .ucon           = S5PV210_UCON_DEFAULT,         \
                .ufcon          = S5PV210_UFCON_DEFAULT,        \
                .has_fracval    = 1,                            \
        }                                                       \

#define EXYNOS_COMMON_SERIAL_DRV_DATA                           \
        EXYNOS_COMMON_SERIAL_DRV_DATA_USI(0)

static struct s3c24xx_serial_drv_data exynos4210_serial_drv_data = {
        EXYNOS_COMMON_SERIAL_DRV_DATA,
        .fifosize = { 256, 64, 16, 16 },
};

static struct s3c24xx_serial_drv_data exynos5433_serial_drv_data = {
        EXYNOS_COMMON_SERIAL_DRV_DATA,
        .fifosize = { 64, 256, 16, 256 },
};

static struct s3c24xx_serial_drv_data exynos850_serial_drv_data = {
        EXYNOS_COMMON_SERIAL_DRV_DATA_USI(1),
        .fifosize = { 256, 64, 64, 64 },
};

#define EXYNOS4210_SERIAL_DRV_DATA ((kernel_ulong_t)&exynos4210_serial_drv_data)
#define EXYNOS5433_SERIAL_DRV_DATA ((kernel_ulong_t)&exynos5433_serial_drv_data)
#define EXYNOS850_SERIAL_DRV_DATA ((kernel_ulong_t)&exynos850_serial_drv_data)

#else
#define EXYNOS4210_SERIAL_DRV_DATA ((kernel_ulong_t)NULL)
#define EXYNOS5433_SERIAL_DRV_DATA ((kernel_ulong_t)NULL)
#define EXYNOS850_SERIAL_DRV_DATA ((kernel_ulong_t)NULL)
#endif

#ifdef CONFIG_ARCH_APPLE
static struct s3c24xx_serial_drv_data s5l_serial_drv_data = {
        .info = &(struct s3c24xx_uart_info) {
                .name           = "Apple S5L UART",
                .type           = TYPE_APPLE_S5L,
                .port_type      = PORT_8250,
                .fifosize       = 16,
                .rx_fifomask    = S3C2410_UFSTAT_RXMASK,
                .rx_fifoshift   = S3C2410_UFSTAT_RXSHIFT,
                .rx_fifofull    = S3C2410_UFSTAT_RXFULL,
                .tx_fifofull    = S3C2410_UFSTAT_TXFULL,
                .tx_fifomask    = S3C2410_UFSTAT_TXMASK,
                .tx_fifoshift   = S3C2410_UFSTAT_TXSHIFT,
                .def_clk_sel    = S3C2410_UCON_CLKSEL0,
                .num_clks       = 1,
                .clksel_mask    = 0,
                .clksel_shift   = 0,
        },
        .def_cfg = &(struct s3c2410_uartcfg) {
                .ucon           = APPLE_S5L_UCON_DEFAULT,
                .ufcon          = S3C2410_UFCON_DEFAULT,
        },
};
#define S5L_SERIAL_DRV_DATA ((kernel_ulong_t)&s5l_serial_drv_data)
#else
#define S5L_SERIAL_DRV_DATA ((kernel_ulong_t)NULL)
#endif

static const struct platform_device_id s3c24xx_serial_driver_ids[] = {
        {
                .name           = "s3c2410-uart",
                .driver_data    = S3C2410_SERIAL_DRV_DATA,
        }, {
                .name           = "s3c2412-uart",
                .driver_data    = S3C2412_SERIAL_DRV_DATA,
        }, {
                .name           = "s3c2440-uart",
                .driver_data    = S3C2440_SERIAL_DRV_DATA,
        }, {
                .name           = "s3c6400-uart",
                .driver_data    = S3C6400_SERIAL_DRV_DATA,
        }, {
                .name           = "s5pv210-uart",
                .driver_data    = S5PV210_SERIAL_DRV_DATA,
        }, {
                .name           = "exynos4210-uart",
                .driver_data    = EXYNOS4210_SERIAL_DRV_DATA,
        }, {
                .name           = "exynos5433-uart",
                .driver_data    = EXYNOS5433_SERIAL_DRV_DATA,
        }, {
                .name           = "s5l-uart",
                .driver_data    = S5L_SERIAL_DRV_DATA,
        }, {
                .name           = "exynos850-uart",
                .driver_data    = EXYNOS850_SERIAL_DRV_DATA,
        },
        { },
};
MODULE_DEVICE_TABLE(platform, s3c24xx_serial_driver_ids);

#ifdef CONFIG_OF
static const struct of_device_id s3c24xx_uart_dt_match[] = {
        { .compatible = "samsung,s3c2410-uart",
                .data = (void *)S3C2410_SERIAL_DRV_DATA },
        { .compatible = "samsung,s3c2412-uart",
                .data = (void *)S3C2412_SERIAL_DRV_DATA },
        { .compatible = "samsung,s3c2440-uart",
                .data = (void *)S3C2440_SERIAL_DRV_DATA },
        { .compatible = "samsung,s3c6400-uart",
                .data = (void *)S3C6400_SERIAL_DRV_DATA },
        { .compatible = "samsung,s5pv210-uart",
                .data = (void *)S5PV210_SERIAL_DRV_DATA },
        { .compatible = "samsung,exynos4210-uart",
                .data = (void *)EXYNOS4210_SERIAL_DRV_DATA },
        { .compatible = "samsung,exynos5433-uart",
                .data = (void *)EXYNOS5433_SERIAL_DRV_DATA },
        { .compatible = "apple,s5l-uart",
                .data = (void *)S5L_SERIAL_DRV_DATA },
        { .compatible = "samsung,exynos850-uart",
                .data = (void *)EXYNOS850_SERIAL_DRV_DATA },
        {},
};
MODULE_DEVICE_TABLE(of, s3c24xx_uart_dt_match);
#endif

static struct platform_driver samsung_serial_driver = {
        .probe          = s3c24xx_serial_probe,
        .remove         = s3c24xx_serial_remove,
        .id_table       = s3c24xx_serial_driver_ids,
        .driver         = {
                .name   = "samsung-uart",
                .pm     = SERIAL_SAMSUNG_PM_OPS,
                .of_match_table = of_match_ptr(s3c24xx_uart_dt_match),
        },
};

module_platform_driver(samsung_serial_driver);

#ifdef CONFIG_SERIAL_SAMSUNG_CONSOLE
/*
 * Early console.
 */

static void wr_reg_barrier(struct uart_port *port, u32 reg, u32 val)
{
        switch (port->iotype) {
        case UPIO_MEM:
                writeb(val, portaddr(port, reg));
                break;
        case UPIO_MEM32:
                writel(val, portaddr(port, reg));
                break;
        }
}

struct samsung_early_console_data {
        u32 txfull_mask;
};

static void samsung_early_busyuart(struct uart_port *port)
{
        while (!(readl(port->membase + S3C2410_UTRSTAT) & S3C2410_UTRSTAT_TXFE))
                ;
}

static void samsung_early_busyuart_fifo(struct uart_port *port)
{
        struct samsung_early_console_data *data = port->private_data;

        while (readl(port->membase + S3C2410_UFSTAT) & data->txfull_mask)
                ;
}

static void samsung_early_putc(struct uart_port *port, int c)
{
        if (readl(port->membase + S3C2410_UFCON) & S3C2410_UFCON_FIFOMODE)
                samsung_early_busyuart_fifo(port);
        else
                samsung_early_busyuart(port);

        wr_reg_barrier(port, S3C2410_UTXH, c);
}

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

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

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

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

/* S3C2410 */
static struct samsung_early_console_data s3c2410_early_console_data = {
        .txfull_mask = S3C2410_UFSTAT_TXFULL,
};

static int __init s3c2410_early_console_setup(struct earlycon_device *device,
                                              const char *opt)
{
        device->port.private_data = &s3c2410_early_console_data;
        return samsung_early_console_setup(device, opt);
}

OF_EARLYCON_DECLARE(s3c2410, "samsung,s3c2410-uart",
                        s3c2410_early_console_setup);

/* S3C2412, S3C2440, S3C64xx */
static struct samsung_early_console_data s3c2440_early_console_data = {
        .txfull_mask = S3C2440_UFSTAT_TXFULL,
};

static int __init s3c2440_early_console_setup(struct earlycon_device *device,
                                              const char *opt)
{
        device->port.private_data = &s3c2440_early_console_data;
        return samsung_early_console_setup(device, opt);
}

OF_EARLYCON_DECLARE(s3c2412, "samsung,s3c2412-uart",
                        s3c2440_early_console_setup);
OF_EARLYCON_DECLARE(s3c2440, "samsung,s3c2440-uart",
                        s3c2440_early_console_setup);
OF_EARLYCON_DECLARE(s3c6400, "samsung,s3c6400-uart",
                        s3c2440_early_console_setup);

/* S5PV210, Exynos */
static struct samsung_early_console_data s5pv210_early_console_data = {
        .txfull_mask = S5PV210_UFSTAT_TXFULL,
};

static int __init s5pv210_early_console_setup(struct earlycon_device *device,
                                              const char *opt)
{
        device->port.private_data = &s5pv210_early_console_data;
        return samsung_early_console_setup(device, opt);
}

OF_EARLYCON_DECLARE(s5pv210, "samsung,s5pv210-uart",
                        s5pv210_early_console_setup);
OF_EARLYCON_DECLARE(exynos4210, "samsung,exynos4210-uart",
                        s5pv210_early_console_setup);

/* Apple S5L */
static int __init apple_s5l_early_console_setup(struct earlycon_device *device,
                                                const char *opt)
{
        /* Close enough to S3C2410 for earlycon... */
        device->port.private_data = &s3c2410_early_console_data;

#ifdef CONFIG_ARM64
        /* ... but we need to override the existing fixmap entry as nGnRnE */
        __set_fixmap(FIX_EARLYCON_MEM_BASE, device->port.mapbase,
                     __pgprot(PROT_DEVICE_nGnRnE));
#endif
        return samsung_early_console_setup(device, opt);
}

OF_EARLYCON_DECLARE(s5l, "apple,s5l-uart", apple_s5l_early_console_setup);
#endif

MODULE_ALIAS("platform:samsung-uart");
MODULE_DESCRIPTION("Samsung SoC Serial port driver");
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
MODULE_LICENSE("GPL v2");