// SPDX-License-Identifier: GPL-2.0
/*
 * SuperH on-chip serial module support.  (SCI with no FIFO / with FIFO)
 *
 *  Copyright (C) 2002 - 2011  Paul Mundt
 *  Copyright (C) 2015 Glider bvba
 *  Modified to support SH7720 SCIF. Markus Brunner, Mark Jonas (Jul 2007).
 *
 * based off of the old drivers/char/sh-sci.c by:
 *
 *   Copyright (C) 1999, 2000  Niibe Yutaka
 *   Copyright (C) 2000  Sugioka Toshinobu
 *   Modified to support multiple serial ports. Stuart Menefy (May 2000).
 *   Modified to support SecureEdge. David McCullough (2002)
 *   Modified to support SH7300 SCIF. Takashi Kusuda (Jun 2003).
 *   Removed SH7300 support (Jul 2007).
 */
#if defined(CONFIG_SERIAL_SH_SCI_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#undef DEBUG

#include <linux/clk.h>
#include <linux/console.h>
#include <linux/ctype.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/ktime.h>
#include <linux/major.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/scatterlist.h>
#include <linux/serial.h>
#include <linux/serial_sci.h>
#include <linux/sh_dma.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/sysrq.h>
#include <linux/timer.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>

#ifdef CONFIG_SUPERH
#include <asm/sh_bios.h>
#endif

#include "serial_mctrl_gpio.h"
#include "sh-sci.h"

/* Offsets into the sci_port->irqs array */
enum {
        SCIx_ERI_IRQ,
        SCIx_RXI_IRQ,
        SCIx_TXI_IRQ,
        SCIx_BRI_IRQ,
        SCIx_DRI_IRQ,
        SCIx_TEI_IRQ,
        SCIx_NR_IRQS,

        SCIx_MUX_IRQ = SCIx_NR_IRQS,    /* special case */
};

#define SCIx_IRQ_IS_MUXED(port)                 \
        ((port)->irqs[SCIx_ERI_IRQ] ==  \
         (port)->irqs[SCIx_RXI_IRQ]) || \
        ((port)->irqs[SCIx_ERI_IRQ] &&  \
         ((port)->irqs[SCIx_RXI_IRQ] < 0))

enum SCI_CLKS {
        SCI_FCK,                /* Functional Clock */
        SCI_SCK,                /* Optional External Clock */
        SCI_BRG_INT,            /* Optional BRG Internal Clock Source */
        SCI_SCIF_CLK,           /* Optional BRG External Clock Source */
        SCI_NUM_CLKS
};

/* Bit x set means sampling rate x + 1 is supported */
#define SCI_SR(x)               BIT((x) - 1)
#define SCI_SR_RANGE(x, y)      GENMASK((y) - 1, (x) - 1)

#define SCI_SR_SCIFAB           SCI_SR(5) | SCI_SR(7) | SCI_SR(11) | \
                                SCI_SR(13) | SCI_SR(16) | SCI_SR(17) | \
                                SCI_SR(19) | SCI_SR(27)

#define min_sr(_port)           ffs((_port)->sampling_rate_mask)
#define max_sr(_port)           fls((_port)->sampling_rate_mask)

/* Iterate over all supported sampling rates, from high to low */
#define for_each_sr(_sr, _port)                                         \
        for ((_sr) = max_sr(_port); (_sr) >= min_sr(_port); (_sr)--)    \
                if ((_port)->sampling_rate_mask & SCI_SR((_sr)))

struct plat_sci_reg {
        u8 offset, size;
};

struct sci_port_params {
        const struct plat_sci_reg regs[SCIx_NR_REGS];
        unsigned int fifosize;
        unsigned int overrun_reg;
        unsigned int overrun_mask;
        unsigned int sampling_rate_mask;
        unsigned int error_mask;
        unsigned int error_clear;
};

struct sci_port {
        struct uart_port        port;

        /* Platform configuration */
        const struct sci_port_params *params;
        const struct plat_sci_port *cfg;
        unsigned int            sampling_rate_mask;
        resource_size_t         reg_size;
        struct mctrl_gpios      *gpios;

        /* Clocks */
        struct clk              *clks[SCI_NUM_CLKS];
        unsigned long           clk_rates[SCI_NUM_CLKS];

        int                     irqs[SCIx_NR_IRQS];
        char                    *irqstr[SCIx_NR_IRQS];

        struct dma_chan                 *chan_tx;
        struct dma_chan                 *chan_rx;

#ifdef CONFIG_SERIAL_SH_SCI_DMA
        struct dma_chan                 *chan_tx_saved;
        struct dma_chan                 *chan_rx_saved;
        dma_cookie_t                    cookie_tx;
        dma_cookie_t                    cookie_rx[2];
        dma_cookie_t                    active_rx;
        dma_addr_t                      tx_dma_addr;
        unsigned int                    tx_dma_len;
        struct scatterlist              sg_rx[2];
        void                            *rx_buf[2];
        size_t                          buf_len_rx;
        struct work_struct              work_tx;
        struct hrtimer                  rx_timer;
        unsigned int                    rx_timeout;     /* microseconds */
#endif
        unsigned int                    rx_frame;
        int                             rx_trigger;
        struct timer_list               rx_fifo_timer;
        int                             rx_fifo_timeout;
        u16                             hscif_tot;

        bool has_rtscts;
        bool autorts;
};

#define SCI_NPORTS CONFIG_SERIAL_SH_SCI_NR_UARTS

static struct sci_port sci_ports[SCI_NPORTS];
static unsigned long sci_ports_in_use;
static struct uart_driver sci_uart_driver;

static inline struct sci_port *
to_sci_port(struct uart_port *uart)
{
        return container_of(uart, struct sci_port, port);
}

static const struct sci_port_params sci_port_params[SCIx_NR_REGTYPES] = {
        /*
         * Common SCI definitions, dependent on the port's regshift
         * value.
         */
        [SCIx_SCI_REGTYPE] = {
                .regs = {
                        [SCSMR]         = { 0x00,  8 },
                        [SCBRR]         = { 0x01,  8 },
                        [SCSCR]         = { 0x02,  8 },
                        [SCxTDR]        = { 0x03,  8 },
                        [SCxSR]         = { 0x04,  8 },
                        [SCxRDR]        = { 0x05,  8 },
                },
                .fifosize = 1,
                .overrun_reg = SCxSR,
                .overrun_mask = SCI_ORER,
                .sampling_rate_mask = SCI_SR(32),
                .error_mask = SCI_DEFAULT_ERROR_MASK | SCI_ORER,
                .error_clear = SCI_ERROR_CLEAR & ~SCI_ORER,
        },

        /*
         * Common definitions for legacy IrDA ports.
         */
        [SCIx_IRDA_REGTYPE] = {
                .regs = {
                        [SCSMR]         = { 0x00,  8 },
                        [SCBRR]         = { 0x02,  8 },
                        [SCSCR]         = { 0x04,  8 },
                        [SCxTDR]        = { 0x06,  8 },
                        [SCxSR]         = { 0x08, 16 },
                        [SCxRDR]        = { 0x0a,  8 },
                        [SCFCR]         = { 0x0c,  8 },
                        [SCFDR]         = { 0x0e, 16 },
                },
                .fifosize = 1,
                .overrun_reg = SCxSR,
                .overrun_mask = SCI_ORER,
                .sampling_rate_mask = SCI_SR(32),
                .error_mask = SCI_DEFAULT_ERROR_MASK | SCI_ORER,
                .error_clear = SCI_ERROR_CLEAR & ~SCI_ORER,
        },

        /*
         * Common SCIFA definitions.
         */
        [SCIx_SCIFA_REGTYPE] = {
                .regs = {
                        [SCSMR]         = { 0x00, 16 },
                        [SCBRR]         = { 0x04,  8 },
                        [SCSCR]         = { 0x08, 16 },
                        [SCxTDR]        = { 0x20,  8 },
                        [SCxSR]         = { 0x14, 16 },
                        [SCxRDR]        = { 0x24,  8 },
                        [SCFCR]         = { 0x18, 16 },
                        [SCFDR]         = { 0x1c, 16 },
                        [SCPCR]         = { 0x30, 16 },
                        [SCPDR]         = { 0x34, 16 },
                },
                .fifosize = 64,
                .overrun_reg = SCxSR,
                .overrun_mask = SCIFA_ORER,
                .sampling_rate_mask = SCI_SR_SCIFAB,
                .error_mask = SCIF_DEFAULT_ERROR_MASK | SCIFA_ORER,
                .error_clear = SCIF_ERROR_CLEAR & ~SCIFA_ORER,
        },

        /*
         * Common SCIFB definitions.
         */
        [SCIx_SCIFB_REGTYPE] = {
                .regs = {
                        [SCSMR]         = { 0x00, 16 },
                        [SCBRR]         = { 0x04,  8 },
                        [SCSCR]         = { 0x08, 16 },
                        [SCxTDR]        = { 0x40,  8 },
                        [SCxSR]         = { 0x14, 16 },
                        [SCxRDR]        = { 0x60,  8 },
                        [SCFCR]         = { 0x18, 16 },
                        [SCTFDR]        = { 0x38, 16 },
                        [SCRFDR]        = { 0x3c, 16 },
                        [SCPCR]         = { 0x30, 16 },
                        [SCPDR]         = { 0x34, 16 },
                },
                .fifosize = 256,
                .overrun_reg = SCxSR,
                .overrun_mask = SCIFA_ORER,
                .sampling_rate_mask = SCI_SR_SCIFAB,
                .error_mask = SCIF_DEFAULT_ERROR_MASK | SCIFA_ORER,
                .error_clear = SCIF_ERROR_CLEAR & ~SCIFA_ORER,
        },

        /*
         * Common SH-2(A) SCIF definitions for ports with FIFO data
         * count registers.
         */
        [SCIx_SH2_SCIF_FIFODATA_REGTYPE] = {
                .regs = {
                        [SCSMR]         = { 0x00, 16 },
                        [SCBRR]         = { 0x04,  8 },
                        [SCSCR]         = { 0x08, 16 },
                        [SCxTDR]        = { 0x0c,  8 },
                        [SCxSR]         = { 0x10, 16 },
                        [SCxRDR]        = { 0x14,  8 },
                        [SCFCR]         = { 0x18, 16 },
                        [SCFDR]         = { 0x1c, 16 },
                        [SCSPTR]        = { 0x20, 16 },
                        [SCLSR]         = { 0x24, 16 },
                },
                .fifosize = 16,
                .overrun_reg = SCLSR,
                .overrun_mask = SCLSR_ORER,
                .sampling_rate_mask = SCI_SR(32),
                .error_mask = SCIF_DEFAULT_ERROR_MASK,
                .error_clear = SCIF_ERROR_CLEAR,
        },

        /*
         * The "SCIFA" that is in RZ/T and RZ/A2.
         * It looks like a normal SCIF with FIFO data, but with a
         * compressed address space. Also, the break out of interrupts
         * are different: ERI/BRI, RXI, TXI, TEI, DRI.
         */
        [SCIx_RZ_SCIFA_REGTYPE] = {
                .regs = {
                        [SCSMR]         = { 0x00, 16 },
                        [SCBRR]         = { 0x02,  8 },
                        [SCSCR]         = { 0x04, 16 },
                        [SCxTDR]        = { 0x06,  8 },
                        [SCxSR]         = { 0x08, 16 },
                        [SCxRDR]        = { 0x0A,  8 },
                        [SCFCR]         = { 0x0C, 16 },
                        [SCFDR]         = { 0x0E, 16 },
                        [SCSPTR]        = { 0x10, 16 },
                        [SCLSR]         = { 0x12, 16 },
                },
                .fifosize = 16,
                .overrun_reg = SCLSR,
                .overrun_mask = SCLSR_ORER,
                .sampling_rate_mask = SCI_SR(32),
                .error_mask = SCIF_DEFAULT_ERROR_MASK,
                .error_clear = SCIF_ERROR_CLEAR,
        },

        /*
         * Common SH-3 SCIF definitions.
         */
        [SCIx_SH3_SCIF_REGTYPE] = {
                .regs = {
                        [SCSMR]         = { 0x00,  8 },
                        [SCBRR]         = { 0x02,  8 },
                        [SCSCR]         = { 0x04,  8 },
                        [SCxTDR]        = { 0x06,  8 },
                        [SCxSR]         = { 0x08, 16 },
                        [SCxRDR]        = { 0x0a,  8 },
                        [SCFCR]         = { 0x0c,  8 },
                        [SCFDR]         = { 0x0e, 16 },
                },
                .fifosize = 16,
                .overrun_reg = SCLSR,
                .overrun_mask = SCLSR_ORER,
                .sampling_rate_mask = SCI_SR(32),
                .error_mask = SCIF_DEFAULT_ERROR_MASK,
                .error_clear = SCIF_ERROR_CLEAR,
        },

        /*
         * Common SH-4(A) SCIF(B) definitions.
         */
        [SCIx_SH4_SCIF_REGTYPE] = {
                .regs = {
                        [SCSMR]         = { 0x00, 16 },
                        [SCBRR]         = { 0x04,  8 },
                        [SCSCR]         = { 0x08, 16 },
                        [SCxTDR]        = { 0x0c,  8 },
                        [SCxSR]         = { 0x10, 16 },
                        [SCxRDR]        = { 0x14,  8 },
                        [SCFCR]         = { 0x18, 16 },
                        [SCFDR]         = { 0x1c, 16 },
                        [SCSPTR]        = { 0x20, 16 },
                        [SCLSR]         = { 0x24, 16 },
                },
                .fifosize = 16,
                .overrun_reg = SCLSR,
                .overrun_mask = SCLSR_ORER,
                .sampling_rate_mask = SCI_SR(32),
                .error_mask = SCIF_DEFAULT_ERROR_MASK,
                .error_clear = SCIF_ERROR_CLEAR,
        },

        /*
         * Common SCIF definitions for ports with a Baud Rate Generator for
         * External Clock (BRG).
         */
        [SCIx_SH4_SCIF_BRG_REGTYPE] = {
                .regs = {
                        [SCSMR]         = { 0x00, 16 },
                        [SCBRR]         = { 0x04,  8 },
                        [SCSCR]         = { 0x08, 16 },
                        [SCxTDR]        = { 0x0c,  8 },
                        [SCxSR]         = { 0x10, 16 },
                        [SCxRDR]        = { 0x14,  8 },
                        [SCFCR]         = { 0x18, 16 },
                        [SCFDR]         = { 0x1c, 16 },
                        [SCSPTR]        = { 0x20, 16 },
                        [SCLSR]         = { 0x24, 16 },
                        [SCDL]          = { 0x30, 16 },
                        [SCCKS]         = { 0x34, 16 },
                },
                .fifosize = 16,
                .overrun_reg = SCLSR,
                .overrun_mask = SCLSR_ORER,
                .sampling_rate_mask = SCI_SR(32),
                .error_mask = SCIF_DEFAULT_ERROR_MASK,
                .error_clear = SCIF_ERROR_CLEAR,
        },

        /*
         * Common HSCIF definitions.
         */
        [SCIx_HSCIF_REGTYPE] = {
                .regs = {
                        [SCSMR]         = { 0x00, 16 },
                        [SCBRR]         = { 0x04,  8 },
                        [SCSCR]         = { 0x08, 16 },
                        [SCxTDR]        = { 0x0c,  8 },
                        [SCxSR]         = { 0x10, 16 },
                        [SCxRDR]        = { 0x14,  8 },
                        [SCFCR]         = { 0x18, 16 },
                        [SCFDR]         = { 0x1c, 16 },
                        [SCSPTR]        = { 0x20, 16 },
                        [SCLSR]         = { 0x24, 16 },
                        [HSSRR]         = { 0x40, 16 },
                        [SCDL]          = { 0x30, 16 },
                        [SCCKS]         = { 0x34, 16 },
                        [HSRTRGR]       = { 0x54, 16 },
                        [HSTTRGR]       = { 0x58, 16 },
                },
                .fifosize = 128,
                .overrun_reg = SCLSR,
                .overrun_mask = SCLSR_ORER,
                .sampling_rate_mask = SCI_SR_RANGE(8, 32),
                .error_mask = SCIF_DEFAULT_ERROR_MASK,
                .error_clear = SCIF_ERROR_CLEAR,
        },

        /*
         * Common SH-4(A) SCIF(B) definitions for ports without an SCSPTR
         * register.
         */
        [SCIx_SH4_SCIF_NO_SCSPTR_REGTYPE] = {
                .regs = {
                        [SCSMR]         = { 0x00, 16 },
                        [SCBRR]         = { 0x04,  8 },
                        [SCSCR]         = { 0x08, 16 },
                        [SCxTDR]        = { 0x0c,  8 },
                        [SCxSR]         = { 0x10, 16 },
                        [SCxRDR]        = { 0x14,  8 },
                        [SCFCR]         = { 0x18, 16 },
                        [SCFDR]         = { 0x1c, 16 },
                        [SCLSR]         = { 0x24, 16 },
                },
                .fifosize = 16,
                .overrun_reg = SCLSR,
                .overrun_mask = SCLSR_ORER,
                .sampling_rate_mask = SCI_SR(32),
                .error_mask = SCIF_DEFAULT_ERROR_MASK,
                .error_clear = SCIF_ERROR_CLEAR,
        },

        /*
         * Common SH-4(A) SCIF(B) definitions for ports with FIFO data
         * count registers.
         */
        [SCIx_SH4_SCIF_FIFODATA_REGTYPE] = {
                .regs = {
                        [SCSMR]         = { 0x00, 16 },
                        [SCBRR]         = { 0x04,  8 },
                        [SCSCR]         = { 0x08, 16 },
                        [SCxTDR]        = { 0x0c,  8 },
                        [SCxSR]         = { 0x10, 16 },
                        [SCxRDR]        = { 0x14,  8 },
                        [SCFCR]         = { 0x18, 16 },
                        [SCFDR]         = { 0x1c, 16 },
                        [SCTFDR]        = { 0x1c, 16 }, /* aliased to SCFDR */
                        [SCRFDR]        = { 0x20, 16 },
                        [SCSPTR]        = { 0x24, 16 },
                        [SCLSR]         = { 0x28, 16 },
                },
                .fifosize = 16,
                .overrun_reg = SCLSR,
                .overrun_mask = SCLSR_ORER,
                .sampling_rate_mask = SCI_SR(32),
                .error_mask = SCIF_DEFAULT_ERROR_MASK,
                .error_clear = SCIF_ERROR_CLEAR,
        },

        /*
         * SH7705-style SCIF(B) ports, lacking both SCSPTR and SCLSR
         * registers.
         */
        [SCIx_SH7705_SCIF_REGTYPE] = {
                .regs = {
                        [SCSMR]         = { 0x00, 16 },
                        [SCBRR]         = { 0x04,  8 },
                        [SCSCR]         = { 0x08, 16 },
                        [SCxTDR]        = { 0x20,  8 },
                        [SCxSR]         = { 0x14, 16 },
                        [SCxRDR]        = { 0x24,  8 },
                        [SCFCR]         = { 0x18, 16 },
                        [SCFDR]         = { 0x1c, 16 },
                },
                .fifosize = 64,
                .overrun_reg = SCxSR,
                .overrun_mask = SCIFA_ORER,
                .sampling_rate_mask = SCI_SR(16),
                .error_mask = SCIF_DEFAULT_ERROR_MASK | SCIFA_ORER,
                .error_clear = SCIF_ERROR_CLEAR & ~SCIFA_ORER,
        },
};

#define sci_getreg(up, offset)          (&to_sci_port(up)->params->regs[offset])

/*
 * The "offset" here is rather misleading, in that it refers to an enum
 * value relative to the port mapping rather than the fixed offset
 * itself, which needs to be manually retrieved from the platform's
 * register map for the given port.
 */
static unsigned int sci_serial_in(struct uart_port *p, int offset)
{
        const struct plat_sci_reg *reg = sci_getreg(p, offset);

        if (reg->size == 8)
                return ioread8(p->membase + (reg->offset << p->regshift));
        else if (reg->size == 16)
                return ioread16(p->membase + (reg->offset << p->regshift));
        else
                WARN(1, "Invalid register access\n");

        return 0;
}

static void sci_serial_out(struct uart_port *p, int offset, int value)
{
        const struct plat_sci_reg *reg = sci_getreg(p, offset);

        if (reg->size == 8)
                iowrite8(value, p->membase + (reg->offset << p->regshift));
        else if (reg->size == 16)
                iowrite16(value, p->membase + (reg->offset << p->regshift));
        else
                WARN(1, "Invalid register access\n");
}

static void sci_port_enable(struct sci_port *sci_port)
{
        unsigned int i;

        if (!sci_port->port.dev)
                return;

        pm_runtime_get_sync(sci_port->port.dev);

        for (i = 0; i < SCI_NUM_CLKS; i++) {
                clk_prepare_enable(sci_port->clks[i]);
                sci_port->clk_rates[i] = clk_get_rate(sci_port->clks[i]);
        }
        sci_port->port.uartclk = sci_port->clk_rates[SCI_FCK];
}

static void sci_port_disable(struct sci_port *sci_port)
{
        unsigned int i;

        if (!sci_port->port.dev)
                return;

        for (i = SCI_NUM_CLKS; i-- > 0; )
                clk_disable_unprepare(sci_port->clks[i]);

        pm_runtime_put_sync(sci_port->port.dev);
}

static inline unsigned long port_rx_irq_mask(struct uart_port *port)
{
        /*
         * Not all ports (such as SCIFA) will support REIE. Rather than
         * special-casing the port type, we check the port initialization
         * IRQ enable mask to see whether the IRQ is desired at all. If
         * it's unset, it's logically inferred that there's no point in
         * testing for it.
         */
        return SCSCR_RIE | (to_sci_port(port)->cfg->scscr & SCSCR_REIE);
}

static void sci_start_tx(struct uart_port *port)
{
        struct sci_port *s = to_sci_port(port);
        unsigned short ctrl;

#ifdef CONFIG_SERIAL_SH_SCI_DMA
        if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) {
                u16 new, scr = serial_port_in(port, SCSCR);
                if (s->chan_tx)
                        new = scr | SCSCR_TDRQE;
                else
                        new = scr & ~SCSCR_TDRQE;
                if (new != scr)
                        serial_port_out(port, SCSCR, new);
        }

        if (s->chan_tx && !uart_circ_empty(&s->port.state->xmit) &&
            dma_submit_error(s->cookie_tx)) {
                s->cookie_tx = 0;
                schedule_work(&s->work_tx);
        }
#endif

        if (!s->chan_tx || port->type == PORT_SCIFA || port->type == PORT_SCIFB) {
                /* Set TIE (Transmit Interrupt Enable) bit in SCSCR */
                ctrl = serial_port_in(port, SCSCR);
                serial_port_out(port, SCSCR, ctrl | SCSCR_TIE);
        }
}

static void sci_stop_tx(struct uart_port *port)
{
        unsigned short ctrl;

        /* Clear TIE (Transmit Interrupt Enable) bit in SCSCR */
        ctrl = serial_port_in(port, SCSCR);

        if (port->type == PORT_SCIFA || port->type == PORT_SCIFB)
                ctrl &= ~SCSCR_TDRQE;

        ctrl &= ~SCSCR_TIE;

        serial_port_out(port, SCSCR, ctrl);
}

static void sci_start_rx(struct uart_port *port)
{
        unsigned short ctrl;

        ctrl = serial_port_in(port, SCSCR) | port_rx_irq_mask(port);

        if (port->type == PORT_SCIFA || port->type == PORT_SCIFB)
                ctrl &= ~SCSCR_RDRQE;

        serial_port_out(port, SCSCR, ctrl);
}

static void sci_stop_rx(struct uart_port *port)
{
        unsigned short ctrl;

        ctrl = serial_port_in(port, SCSCR);

        if (port->type == PORT_SCIFA || port->type == PORT_SCIFB)
                ctrl &= ~SCSCR_RDRQE;

        ctrl &= ~port_rx_irq_mask(port);

        serial_port_out(port, SCSCR, ctrl);
}

static void sci_clear_SCxSR(struct uart_port *port, unsigned int mask)
{
        if (port->type == PORT_SCI) {
                /* Just store the mask */
                serial_port_out(port, SCxSR, mask);
        } else if (to_sci_port(port)->params->overrun_mask == SCIFA_ORER) {
                /* SCIFA/SCIFB and SCIF on SH7705/SH7720/SH7721 */
                /* Only clear the status bits we want to clear */
                serial_port_out(port, SCxSR,
                                serial_port_in(port, SCxSR) & mask);
        } else {
                /* Store the mask, clear parity/framing errors */
                serial_port_out(port, SCxSR, mask & ~(SCIF_FERC | SCIF_PERC));
        }
}

#if defined(CONFIG_CONSOLE_POLL) || defined(CONFIG_SERIAL_SH_SCI_CONSOLE) || \
    defined(CONFIG_SERIAL_SH_SCI_EARLYCON)

#ifdef CONFIG_CONSOLE_POLL
static int sci_poll_get_char(struct uart_port *port)
{
        unsigned short status;
        int c;

        do {
                status = serial_port_in(port, SCxSR);
                if (status & SCxSR_ERRORS(port)) {
                        sci_clear_SCxSR(port, SCxSR_ERROR_CLEAR(port));
                        continue;
                }
                break;
        } while (1);

        if (!(status & SCxSR_RDxF(port)))
                return NO_POLL_CHAR;

        c = serial_port_in(port, SCxRDR);

        /* Dummy read */
        serial_port_in(port, SCxSR);
        sci_clear_SCxSR(port, SCxSR_RDxF_CLEAR(port));

        return c;
}
#endif

static void sci_poll_put_char(struct uart_port *port, unsigned char c)
{
        unsigned short status;

        do {
                status = serial_port_in(port, SCxSR);
        } while (!(status & SCxSR_TDxE(port)));

        serial_port_out(port, SCxTDR, c);
        sci_clear_SCxSR(port, SCxSR_TDxE_CLEAR(port) & ~SCxSR_TEND(port));
}
#endif /* CONFIG_CONSOLE_POLL || CONFIG_SERIAL_SH_SCI_CONSOLE ||
          CONFIG_SERIAL_SH_SCI_EARLYCON */

static void sci_init_pins(struct uart_port *port, unsigned int cflag)
{
        struct sci_port *s = to_sci_port(port);

        /*
         * Use port-specific handler if provided.
         */
        if (s->cfg->ops && s->cfg->ops->init_pins) {
                s->cfg->ops->init_pins(port, cflag);
                return;
        }

        if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) {
                u16 data = serial_port_in(port, SCPDR);
                u16 ctrl = serial_port_in(port, SCPCR);

                /* Enable RXD and TXD pin functions */
                ctrl &= ~(SCPCR_RXDC | SCPCR_TXDC);
                if (to_sci_port(port)->has_rtscts) {
                        /* RTS# is output, active low, unless autorts */
                        if (!(port->mctrl & TIOCM_RTS)) {
                                ctrl |= SCPCR_RTSC;
                                data |= SCPDR_RTSD;
                        } else if (!s->autorts) {
                                ctrl |= SCPCR_RTSC;
                                data &= ~SCPDR_RTSD;
                        } else {
                                /* Enable RTS# pin function */
                                ctrl &= ~SCPCR_RTSC;
                        }
                        /* Enable CTS# pin function */
                        ctrl &= ~SCPCR_CTSC;
                }
                serial_port_out(port, SCPDR, data);
                serial_port_out(port, SCPCR, ctrl);
        } else if (sci_getreg(port, SCSPTR)->size) {
                u16 status = serial_port_in(port, SCSPTR);

                /* RTS# is always output; and active low, unless autorts */
                status |= SCSPTR_RTSIO;
                if (!(port->mctrl & TIOCM_RTS))
                        status |= SCSPTR_RTSDT;
                else if (!s->autorts)
                        status &= ~SCSPTR_RTSDT;
                /* CTS# and SCK are inputs */
                status &= ~(SCSPTR_CTSIO | SCSPTR_SCKIO);
                serial_port_out(port, SCSPTR, status);
        }
}

static int sci_txfill(struct uart_port *port)
{
        struct sci_port *s = to_sci_port(port);
        unsigned int fifo_mask = (s->params->fifosize << 1) - 1;
        const struct plat_sci_reg *reg;

        reg = sci_getreg(port, SCTFDR);
        if (reg->size)
                return serial_port_in(port, SCTFDR) & fifo_mask;

        reg = sci_getreg(port, SCFDR);
        if (reg->size)
                return serial_port_in(port, SCFDR) >> 8;

        return !(serial_port_in(port, SCxSR) & SCI_TDRE);
}

static int sci_txroom(struct uart_port *port)
{
        return port->fifosize - sci_txfill(port);
}

static int sci_rxfill(struct uart_port *port)
{
        struct sci_port *s = to_sci_port(port);
        unsigned int fifo_mask = (s->params->fifosize << 1) - 1;
        const struct plat_sci_reg *reg;

        reg = sci_getreg(port, SCRFDR);
        if (reg->size)
                return serial_port_in(port, SCRFDR) & fifo_mask;

        reg = sci_getreg(port, SCFDR);
        if (reg->size)
                return serial_port_in(port, SCFDR) & fifo_mask;

        return (serial_port_in(port, SCxSR) & SCxSR_RDxF(port)) != 0;
}

/* ********************************************************************** *
 *                   the interrupt related routines                       *
 * ********************************************************************** */

static void sci_transmit_chars(struct uart_port *port)
{
        struct circ_buf *xmit = &port->state->xmit;
        unsigned int stopped = uart_tx_stopped(port);
        unsigned short status;
        unsigned short ctrl;
        int count;

        status = serial_port_in(port, SCxSR);
        if (!(status & SCxSR_TDxE(port))) {
                ctrl = serial_port_in(port, SCSCR);
                if (uart_circ_empty(xmit))
                        ctrl &= ~SCSCR_TIE;
                else
                        ctrl |= SCSCR_TIE;
                serial_port_out(port, SCSCR, ctrl);
                return;
        }

        count = sci_txroom(port);

        do {
                unsigned char c;

                if (port->x_char) {
                        c = port->x_char;
                        port->x_char = 0;
                } else if (!uart_circ_empty(xmit) && !stopped) {
                        c = xmit->buf[xmit->tail];
                        xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                } else {
                        break;
                }

                serial_port_out(port, SCxTDR, c);

                port->icount.tx++;
        } while (--count > 0);

        sci_clear_SCxSR(port, SCxSR_TDxE_CLEAR(port));

        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
                uart_write_wakeup(port);
        if (uart_circ_empty(xmit)) {
                sci_stop_tx(port);
        } else {
                ctrl = serial_port_in(port, SCSCR);

                if (port->type != PORT_SCI) {
                        serial_port_in(port, SCxSR); /* Dummy read */
                        sci_clear_SCxSR(port, SCxSR_TDxE_CLEAR(port));
                }

                ctrl |= SCSCR_TIE;
                serial_port_out(port, SCSCR, ctrl);
        }
}

/* On SH3, SCIF may read end-of-break as a space->mark char */
#define STEPFN(c)  ({int __c = (c); (((__c-1)|(__c)) == -1); })

static void sci_receive_chars(struct uart_port *port)
{
        struct tty_port *tport = &port->state->port;
        int i, count, copied = 0;
        unsigned short status;
        unsigned char flag;

        status = serial_port_in(port, SCxSR);
        if (!(status & SCxSR_RDxF(port)))
                return;

        while (1) {
                /* Don't copy more bytes than there is room for in the buffer */
                count = tty_buffer_request_room(tport, sci_rxfill(port));

                /* If for any reason we can't copy more data, we're done! */
                if (count == 0)
                        break;

                if (port->type == PORT_SCI) {
                        char c = serial_port_in(port, SCxRDR);
                        if (uart_handle_sysrq_char(port, c))
                                count = 0;
                        else
                                tty_insert_flip_char(tport, c, TTY_NORMAL);
                } else {
                        for (i = 0; i < count; i++) {
                                char c = serial_port_in(port, SCxRDR);

                                status = serial_port_in(port, SCxSR);
                                if (uart_handle_sysrq_char(port, c)) {
                                        count--; i--;
                                        continue;
                                }

                                /* Store data and status */
                                if (status & SCxSR_FER(port)) {
                                        flag = TTY_FRAME;
                                        port->icount.frame++;
                                        dev_notice(port->dev, "frame error\n");
                                } else if (status & SCxSR_PER(port)) {
                                        flag = TTY_PARITY;
                                        port->icount.parity++;
                                        dev_notice(port->dev, "parity error\n");
                                } else
                                        flag = TTY_NORMAL;

                                tty_insert_flip_char(tport, c, flag);
                        }
                }

                serial_port_in(port, SCxSR); /* dummy read */
                sci_clear_SCxSR(port, SCxSR_RDxF_CLEAR(port));

                copied += count;
                port->icount.rx += count;
        }

        if (copied) {
                /* Tell the rest of the system the news. New characters! */
                tty_flip_buffer_push(tport);
        } else {
                /* TTY buffers full; read from RX reg to prevent lockup */
                serial_port_in(port, SCxRDR);
                serial_port_in(port, SCxSR); /* dummy read */
                sci_clear_SCxSR(port, SCxSR_RDxF_CLEAR(port));
        }
}

static int sci_handle_errors(struct uart_port *port)
{
        int copied = 0;
        unsigned short status = serial_port_in(port, SCxSR);
        struct tty_port *tport = &port->state->port;
        struct sci_port *s = to_sci_port(port);

        /* Handle overruns */
        if (status & s->params->overrun_mask) {
                port->icount.overrun++;

                /* overrun error */
                if (tty_insert_flip_char(tport, 0, TTY_OVERRUN))
                        copied++;

                dev_notice(port->dev, "overrun error\n");
        }

        if (status & SCxSR_FER(port)) {
                /* frame error */
                port->icount.frame++;

                if (tty_insert_flip_char(tport, 0, TTY_FRAME))
                        copied++;

                dev_notice(port->dev, "frame error\n");
        }

        if (status & SCxSR_PER(port)) {
                /* parity error */
                port->icount.parity++;

                if (tty_insert_flip_char(tport, 0, TTY_PARITY))
                        copied++;

                dev_notice(port->dev, "parity error\n");
        }

        if (copied)
                tty_flip_buffer_push(tport);

        return copied;
}

static int sci_handle_fifo_overrun(struct uart_port *port)
{
        struct tty_port *tport = &port->state->port;
        struct sci_port *s = to_sci_port(port);
        const struct plat_sci_reg *reg;
        int copied = 0;
        u16 status;

        reg = sci_getreg(port, s->params->overrun_reg);
        if (!reg->size)
                return 0;

        status = serial_port_in(port, s->params->overrun_reg);
        if (status & s->params->overrun_mask) {
                status &= ~s->params->overrun_mask;
                serial_port_out(port, s->params->overrun_reg, status);

                port->icount.overrun++;

                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
                tty_flip_buffer_push(tport);

                dev_dbg(port->dev, "overrun error\n");
                copied++;
        }

        return copied;
}

static int sci_handle_breaks(struct uart_port *port)
{
        int copied = 0;
        unsigned short status = serial_port_in(port, SCxSR);
        struct tty_port *tport = &port->state->port;

        if (uart_handle_break(port))
                return 0;

        if (status & SCxSR_BRK(port)) {
                port->icount.brk++;

                /* Notify of BREAK */
                if (tty_insert_flip_char(tport, 0, TTY_BREAK))
                        copied++;

                dev_dbg(port->dev, "BREAK detected\n");
        }

        if (copied)
                tty_flip_buffer_push(tport);

        copied += sci_handle_fifo_overrun(port);

        return copied;
}

static int scif_set_rtrg(struct uart_port *port, int rx_trig)
{
        unsigned int bits;

        if (rx_trig < 1)
                rx_trig = 1;
        if (rx_trig >= port->fifosize)
                rx_trig = port->fifosize;

        /* HSCIF can be set to an arbitrary level. */
        if (sci_getreg(port, HSRTRGR)->size) {
                serial_port_out(port, HSRTRGR, rx_trig);
                return rx_trig;
        }

        switch (port->type) {
        case PORT_SCIF:
                if (rx_trig < 4) {
                        bits = 0;
                        rx_trig = 1;
                } else if (rx_trig < 8) {
                        bits = SCFCR_RTRG0;
                        rx_trig = 4;
                } else if (rx_trig < 14) {
                        bits = SCFCR_RTRG1;
                        rx_trig = 8;
                } else {
                        bits = SCFCR_RTRG0 | SCFCR_RTRG1;
                        rx_trig = 14;
                }
                break;
        case PORT_SCIFA:
        case PORT_SCIFB:
                if (rx_trig < 16) {
                        bits = 0;
                        rx_trig = 1;
                } else if (rx_trig < 32) {
                        bits = SCFCR_RTRG0;
                        rx_trig = 16;
                } else if (rx_trig < 48) {
                        bits = SCFCR_RTRG1;
                        rx_trig = 32;
                } else {
                        bits = SCFCR_RTRG0 | SCFCR_RTRG1;
                        rx_trig = 48;
                }
                break;
        default:
                WARN(1, "unknown FIFO configuration");
                return 1;
        }

        serial_port_out(port, SCFCR,
                (serial_port_in(port, SCFCR) &
                ~(SCFCR_RTRG1 | SCFCR_RTRG0)) | bits);

        return rx_trig;
}

static int scif_rtrg_enabled(struct uart_port *port)
{
        if (sci_getreg(port, HSRTRGR)->size)
                return serial_port_in(port, HSRTRGR) != 0;
        else
                return (serial_port_in(port, SCFCR) &
                        (SCFCR_RTRG0 | SCFCR_RTRG1)) != 0;
}

static void rx_fifo_timer_fn(struct timer_list *t)
{
        struct sci_port *s = from_timer(s, t, rx_fifo_timer);
        struct uart_port *port = &s->port;

        dev_dbg(port->dev, "Rx timed out\n");
        scif_set_rtrg(port, 1);
}

static ssize_t rx_trigger_show(struct device *dev,
                               struct device_attribute *attr,
                               char *buf)
{
        struct uart_port *port = dev_get_drvdata(dev);
        struct sci_port *sci = to_sci_port(port);

        return sprintf(buf, "%d\n", sci->rx_trigger);
}

static ssize_t rx_trigger_store(struct device *dev,
                                struct device_attribute *attr,
                                const char *buf,
                                size_t count)
{
        struct uart_port *port = dev_get_drvdata(dev);
        struct sci_port *sci = to_sci_port(port);
        int ret;
        long r;

        ret = kstrtol(buf, 0, &r);
        if (ret)
                return ret;

        sci->rx_trigger = scif_set_rtrg(port, r);
        if (port->type == PORT_SCIFA || port->type == PORT_SCIFB)
                scif_set_rtrg(port, 1);

        return count;
}

static DEVICE_ATTR(rx_fifo_trigger, 0644, rx_trigger_show, rx_trigger_store);

static ssize_t rx_fifo_timeout_show(struct device *dev,
                               struct device_attribute *attr,
                               char *buf)
{
        struct uart_port *port = dev_get_drvdata(dev);
        struct sci_port *sci = to_sci_port(port);
        int v;

        if (port->type == PORT_HSCIF)
                v = sci->hscif_tot >> HSSCR_TOT_SHIFT;
        else
                v = sci->rx_fifo_timeout;

        return sprintf(buf, "%d\n", v);
}

static ssize_t rx_fifo_timeout_store(struct device *dev,
                                struct device_attribute *attr,
                                const char *buf,
                                size_t count)
{
        struct uart_port *port = dev_get_drvdata(dev);
        struct sci_port *sci = to_sci_port(port);
        int ret;
        long r;

        ret = kstrtol(buf, 0, &r);
        if (ret)
                return ret;

        if (port->type == PORT_HSCIF) {
                if (r < 0 || r > 3)
                        return -EINVAL;
                sci->hscif_tot = r << HSSCR_TOT_SHIFT;
        } else {
                sci->rx_fifo_timeout = r;
                scif_set_rtrg(port, 1);
                if (r > 0)
                        timer_setup(&sci->rx_fifo_timer, rx_fifo_timer_fn, 0);
        }

        return count;
}

static DEVICE_ATTR_RW(rx_fifo_timeout);


#ifdef CONFIG_SERIAL_SH_SCI_DMA
static void sci_dma_tx_complete(void *arg)
{
        struct sci_port *s = arg;
        struct uart_port *port = &s->port;
        struct circ_buf *xmit = &port->state->xmit;
        unsigned long flags;

        dev_dbg(port->dev, "%s(%d)\n", __func__, port->line);

        spin_lock_irqsave(&port->lock, flags);

        xmit->tail += s->tx_dma_len;
        xmit->tail &= UART_XMIT_SIZE - 1;

        port->icount.tx += s->tx_dma_len;

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

        if (!uart_circ_empty(xmit)) {
                s->cookie_tx = 0;
                schedule_work(&s->work_tx);
        } else {
                s->cookie_tx = -EINVAL;
                if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) {
                        u16 ctrl = serial_port_in(port, SCSCR);
                        serial_port_out(port, SCSCR, ctrl & ~SCSCR_TIE);
                }
        }

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

/* Locking: called with port lock held */
static int sci_dma_rx_push(struct sci_port *s, void *buf, size_t count)
{
        struct uart_port *port = &s->port;
        struct tty_port *tport = &port->state->port;
        int copied;

        copied = tty_insert_flip_string(tport, buf, count);
        if (copied < count)
                port->icount.buf_overrun++;

        port->icount.rx += copied;

        return copied;
}

static int sci_dma_rx_find_active(struct sci_port *s)
{
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(s->cookie_rx); i++)
                if (s->active_rx == s->cookie_rx[i])
                        return i;

        return -1;
}

static void sci_rx_dma_release(struct sci_port *s)
{
        struct dma_chan *chan = s->chan_rx_saved;

        s->chan_rx_saved = s->chan_rx = NULL;
        s->cookie_rx[0] = s->cookie_rx[1] = -EINVAL;
        dmaengine_terminate_sync(chan);
        dma_free_coherent(chan->device->dev, s->buf_len_rx * 2, s->rx_buf[0],
                          sg_dma_address(&s->sg_rx[0]));
        dma_release_channel(chan);
}

static void start_hrtimer_us(struct hrtimer *hrt, unsigned long usec)
{
        long sec = usec / 1000000;
        long nsec = (usec % 1000000) * 1000;
        ktime_t t = ktime_set(sec, nsec);

        hrtimer_start(hrt, t, HRTIMER_MODE_REL);
}

static void sci_dma_rx_complete(void *arg)
{
        struct sci_port *s = arg;
        struct dma_chan *chan = s->chan_rx;
        struct uart_port *port = &s->port;
        struct dma_async_tx_descriptor *desc;
        unsigned long flags;
        int active, count = 0;

        dev_dbg(port->dev, "%s(%d) active cookie %d\n", __func__, port->line,
                s->active_rx);

        spin_lock_irqsave(&port->lock, flags);

        active = sci_dma_rx_find_active(s);
        if (active >= 0)
                count = sci_dma_rx_push(s, s->rx_buf[active], s->buf_len_rx);

        start_hrtimer_us(&s->rx_timer, s->rx_timeout);

        if (count)
                tty_flip_buffer_push(&port->state->port);

        desc = dmaengine_prep_slave_sg(s->chan_rx, &s->sg_rx[active], 1,
                                       DMA_DEV_TO_MEM,
                                       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!desc)
                goto fail;

        desc->callback = sci_dma_rx_complete;
        desc->callback_param = s;
        s->cookie_rx[active] = dmaengine_submit(desc);
        if (dma_submit_error(s->cookie_rx[active]))
                goto fail;

        s->active_rx = s->cookie_rx[!active];

        dma_async_issue_pending(chan);

        spin_unlock_irqrestore(&port->lock, flags);
        dev_dbg(port->dev, "%s: cookie %d #%d, new active cookie %d\n",
                __func__, s->cookie_rx[active], active, s->active_rx);
        return;

fail:
        spin_unlock_irqrestore(&port->lock, flags);
        dev_warn(port->dev, "Failed submitting Rx DMA descriptor\n");
        /* Switch to PIO */
        spin_lock_irqsave(&port->lock, flags);
        s->chan_rx = NULL;
        sci_start_rx(port);
        spin_unlock_irqrestore(&port->lock, flags);
}

static void sci_tx_dma_release(struct sci_port *s)
{
        struct dma_chan *chan = s->chan_tx_saved;

        cancel_work_sync(&s->work_tx);
        s->chan_tx_saved = s->chan_tx = NULL;
        s->cookie_tx = -EINVAL;
        dmaengine_terminate_sync(chan);
        dma_unmap_single(chan->device->dev, s->tx_dma_addr, UART_XMIT_SIZE,
                         DMA_TO_DEVICE);
        dma_release_channel(chan);
}

static void sci_submit_rx(struct sci_port *s)
{
        struct dma_chan *chan = s->chan_rx;
        struct uart_port *port = &s->port;
        unsigned long flags;
        int i;

        for (i = 0; i < 2; i++) {
                struct scatterlist *sg = &s->sg_rx[i];
                struct dma_async_tx_descriptor *desc;

                desc = dmaengine_prep_slave_sg(chan,
                        sg, 1, DMA_DEV_TO_MEM,
                        DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
                if (!desc)
                        goto fail;

                desc->callback = sci_dma_rx_complete;
                desc->callback_param = s;
                s->cookie_rx[i] = dmaengine_submit(desc);
                if (dma_submit_error(s->cookie_rx[i]))
                        goto fail;

        }

        s->active_rx = s->cookie_rx[0];

        dma_async_issue_pending(chan);
        return;

fail:
        if (i)
                dmaengine_terminate_async(chan);
        for (i = 0; i < 2; i++)
                s->cookie_rx[i] = -EINVAL;
        s->active_rx = -EINVAL;
        /* Switch to PIO */
        spin_lock_irqsave(&port->lock, flags);
        s->chan_rx = NULL;
        sci_start_rx(port);
        spin_unlock_irqrestore(&port->lock, flags);
}

static void work_fn_tx(struct work_struct *work)
{
        struct sci_port *s = container_of(work, struct sci_port, work_tx);
        struct dma_async_tx_descriptor *desc;
        struct dma_chan *chan = s->chan_tx;
        struct uart_port *port = &s->port;
        struct circ_buf *xmit = &port->state->xmit;
        unsigned long flags;
        dma_addr_t buf;

        /*
         * DMA is idle now.
         * Port xmit buffer is already mapped, and it is one page... Just adjust
         * offsets and lengths. Since it is a circular buffer, we have to
         * transmit till the end, and then the rest. Take the port lock to get a
         * consistent xmit buffer state.
         */
        spin_lock_irq(&port->lock);
        buf = s->tx_dma_addr + (xmit->tail & (UART_XMIT_SIZE - 1));
        s->tx_dma_len = min_t(unsigned int,
                CIRC_CNT(xmit->head, xmit->tail, UART_XMIT_SIZE),
                CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE));
        spin_unlock_irq(&port->lock);

        desc = dmaengine_prep_slave_single(chan, buf, s->tx_dma_len,
                                           DMA_MEM_TO_DEV,
                                           DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!desc) {
                dev_warn(port->dev, "Failed preparing Tx DMA descriptor\n");
                goto switch_to_pio;
        }

        dma_sync_single_for_device(chan->device->dev, buf, s->tx_dma_len,
                                   DMA_TO_DEVICE);

        spin_lock_irq(&port->lock);
        desc->callback = sci_dma_tx_complete;
        desc->callback_param = s;
        spin_unlock_irq(&port->lock);
        s->cookie_tx = dmaengine_submit(desc);
        if (dma_submit_error(s->cookie_tx)) {
                dev_warn(port->dev, "Failed submitting Tx DMA descriptor\n");
                goto switch_to_pio;
        }

        dev_dbg(port->dev, "%s: %p: %d...%d, cookie %d\n",
                __func__, xmit->buf, xmit->tail, xmit->head, s->cookie_tx);

        dma_async_issue_pending(chan);
        return;

switch_to_pio:
        spin_lock_irqsave(&port->lock, flags);
        s->chan_tx = NULL;
        sci_start_tx(port);
        spin_unlock_irqrestore(&port->lock, flags);
        return;
}

static enum hrtimer_restart rx_timer_fn(struct hrtimer *t)
{
        struct sci_port *s = container_of(t, struct sci_port, rx_timer);
        struct dma_chan *chan = s->chan_rx;
        struct uart_port *port = &s->port;
        struct dma_tx_state state;
        enum dma_status status;
        unsigned long flags;
        unsigned int read;
        int active, count;
        u16 scr;

        dev_dbg(port->dev, "DMA Rx timed out\n");

        spin_lock_irqsave(&port->lock, flags);

        active = sci_dma_rx_find_active(s);
        if (active < 0) {
                spin_unlock_irqrestore(&port->lock, flags);
                return HRTIMER_NORESTART;
        }

        status = dmaengine_tx_status(s->chan_rx, s->active_rx, &state);
        if (status == DMA_COMPLETE) {
                spin_unlock_irqrestore(&port->lock, flags);
                dev_dbg(port->dev, "Cookie %d #%d has already completed\n",
                        s->active_rx, active);

                /* Let packet complete handler take care of the packet */
                return HRTIMER_NORESTART;
        }

        dmaengine_pause(chan);

        /*
         * sometimes DMA transfer doesn't stop even if it is stopped and
         * data keeps on coming until transaction is complete so check
         * for DMA_COMPLETE again
         * Let packet complete handler take care of the packet
         */
        status = dmaengine_tx_status(s->chan_rx, s->active_rx, &state);
        if (status == DMA_COMPLETE) {
                spin_unlock_irqrestore(&port->lock, flags);
                dev_dbg(port->dev, "Transaction complete after DMA engine was stopped");
                return HRTIMER_NORESTART;
        }

        /* Handle incomplete DMA receive */
        dmaengine_terminate_async(s->chan_rx);
        read = sg_dma_len(&s->sg_rx[active]) - state.residue;

        if (read) {
                count = sci_dma_rx_push(s, s->rx_buf[active], read);
                if (count)
                        tty_flip_buffer_push(&port->state->port);
        }

        if (port->type == PORT_SCIFA || port->type == PORT_SCIFB)
                sci_submit_rx(s);

        /* Direct new serial port interrupts back to CPU */
        scr = serial_port_in(port, SCSCR);
        if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) {
                scr &= ~SCSCR_RDRQE;
                enable_irq(s->irqs[SCIx_RXI_IRQ]);
        }
        serial_port_out(port, SCSCR, scr | SCSCR_RIE);

        spin_unlock_irqrestore(&port->lock, flags);

        return HRTIMER_NORESTART;
}

static struct dma_chan *sci_request_dma_chan(struct uart_port *port,
                                             enum dma_transfer_direction dir)
{
        struct dma_chan *chan;
        struct dma_slave_config cfg;
        int ret;

        chan = dma_request_slave_channel(port->dev,
                                         dir == DMA_MEM_TO_DEV ? "tx" : "rx");
        if (!chan) {
                dev_dbg(port->dev, "dma_request_slave_channel failed\n");
                return NULL;
        }

        memset(&cfg, 0, sizeof(cfg));
        cfg.direction = dir;
        if (dir == DMA_MEM_TO_DEV) {
                cfg.dst_addr = port->mapbase +
                        (sci_getreg(port, SCxTDR)->offset << port->regshift);
                cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
        } else {
                cfg.src_addr = port->mapbase +
                        (sci_getreg(port, SCxRDR)->offset << port->regshift);
                cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
        }

        ret = dmaengine_slave_config(chan, &cfg);
        if (ret) {
                dev_warn(port->dev, "dmaengine_slave_config failed %d\n", ret);
                dma_release_channel(chan);
                return NULL;
        }

        return chan;
}

static void sci_request_dma(struct uart_port *port)
{
        struct sci_port *s = to_sci_port(port);
        struct dma_chan *chan;

        dev_dbg(port->dev, "%s: port %d\n", __func__, port->line);

        if (!port->dev->of_node)
                return;

        s->cookie_tx = -EINVAL;

        /*
         * Don't request a dma channel if no channel was specified
         * in the device tree.
         */
        if (!of_find_property(port->dev->of_node, "dmas", NULL))
                return;

        chan = sci_request_dma_chan(port, DMA_MEM_TO_DEV);
        dev_dbg(port->dev, "%s: TX: got channel %p\n", __func__, chan);
        if (chan) {
                /* UART circular tx buffer is an aligned page. */
                s->tx_dma_addr = dma_map_single(chan->device->dev,
                                                port->state->xmit.buf,
                                                UART_XMIT_SIZE,
                                                DMA_TO_DEVICE);
                if (dma_mapping_error(chan->device->dev, s->tx_dma_addr)) {
                        dev_warn(port->dev, "Failed mapping Tx DMA descriptor\n");
                        dma_release_channel(chan);
                } else {
                        dev_dbg(port->dev, "%s: mapped %lu@%p to %pad\n",
                                __func__, UART_XMIT_SIZE,
                                port->state->xmit.buf, &s->tx_dma_addr);

                        INIT_WORK(&s->work_tx, work_fn_tx);
                        s->chan_tx_saved = s->chan_tx = chan;
                }
        }

        chan = sci_request_dma_chan(port, DMA_DEV_TO_MEM);
        dev_dbg(port->dev, "%s: RX: got channel %p\n", __func__, chan);
        if (chan) {
                unsigned int i;
                dma_addr_t dma;
                void *buf;

                s->buf_len_rx = 2 * max_t(size_t, 16, port->fifosize);
                buf = dma_alloc_coherent(chan->device->dev, s->buf_len_rx * 2,
                                         &dma, GFP_KERNEL);
                if (!buf) {
                        dev_warn(port->dev,
                                 "Failed to allocate Rx dma buffer, using PIO\n");
                        dma_release_channel(chan);
                        return;
                }

                for (i = 0; i < 2; i++) {
                        struct scatterlist *sg = &s->sg_rx[i];

                        sg_init_table(sg, 1);
                        s->rx_buf[i] = buf;
                        sg_dma_address(sg) = dma;
                        sg_dma_len(sg) = s->buf_len_rx;

                        buf += s->buf_len_rx;
                        dma += s->buf_len_rx;
                }

                hrtimer_init(&s->rx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
                s->rx_timer.function = rx_timer_fn;

                s->chan_rx_saved = s->chan_rx = chan;

                if (port->type == PORT_SCIFA || port->type == PORT_SCIFB)
                        sci_submit_rx(s);
        }
}

static void sci_free_dma(struct uart_port *port)
{
        struct sci_port *s = to_sci_port(port);

        if (s->chan_tx_saved)
                sci_tx_dma_release(s);
        if (s->chan_rx_saved)
                sci_rx_dma_release(s);
}

static void sci_flush_buffer(struct uart_port *port)
{
        /*
         * In uart_flush_buffer(), the xmit circular buffer has just been
         * cleared, so we have to reset tx_dma_len accordingly.
         */
        to_sci_port(port)->tx_dma_len = 0;
}
#else /* !CONFIG_SERIAL_SH_SCI_DMA */
static inline void sci_request_dma(struct uart_port *port)
{
}

static inline void sci_free_dma(struct uart_port *port)
{
}

#define sci_flush_buffer        NULL
#endif /* !CONFIG_SERIAL_SH_SCI_DMA */

static irqreturn_t sci_rx_interrupt(int irq, void *ptr)
{
        struct uart_port *port = ptr;
        struct sci_port *s = to_sci_port(port);

#ifdef CONFIG_SERIAL_SH_SCI_DMA
        if (s->chan_rx) {
                u16 scr = serial_port_in(port, SCSCR);
                u16 ssr = serial_port_in(port, SCxSR);

                /* Disable future Rx interrupts */
                if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) {
                        disable_irq_nosync(irq);
                        scr |= SCSCR_RDRQE;
                } else {
                        scr &= ~SCSCR_RIE;
                        sci_submit_rx(s);
                }
                serial_port_out(port, SCSCR, scr);
                /* Clear current interrupt */
                serial_port_out(port, SCxSR,
                                ssr & ~(SCIF_DR | SCxSR_RDxF(port)));
                dev_dbg(port->dev, "Rx IRQ %lu: setup t-out in %u us\n",
                        jiffies, s->rx_timeout);
                start_hrtimer_us(&s->rx_timer, s->rx_timeout);

                return IRQ_HANDLED;
        }
#endif

        if (s->rx_trigger > 1 && s->rx_fifo_timeout > 0) {
                if (!scif_rtrg_enabled(port))
                        scif_set_rtrg(port, s->rx_trigger);

                mod_timer(&s->rx_fifo_timer, jiffies + DIV_ROUND_UP(
                          s->rx_frame * HZ * s->rx_fifo_timeout, 1000000));
        }

        /* I think sci_receive_chars has to be called irrespective
         * of whether the I_IXOFF is set, otherwise, how is the interrupt
         * to be disabled?
         */
        sci_receive_chars(ptr);

        return IRQ_HANDLED;
}

static irqreturn_t sci_tx_interrupt(int irq, void *ptr)
{
        struct uart_port *port = ptr;
        unsigned long flags;

        spin_lock_irqsave(&port->lock, flags);
        sci_transmit_chars(port);
        spin_unlock_irqrestore(&port->lock, flags);

        return IRQ_HANDLED;
}

static irqreturn_t sci_br_interrupt(int irq, void *ptr)
{
        struct uart_port *port = ptr;

        /* Handle BREAKs */
        sci_handle_breaks(port);
        sci_clear_SCxSR(port, SCxSR_BREAK_CLEAR(port));

        return IRQ_HANDLED;
}

static irqreturn_t sci_er_interrupt(int irq, void *ptr)
{
        struct uart_port *port = ptr;
        struct sci_port *s = to_sci_port(port);

        if (s->irqs[SCIx_ERI_IRQ] == s->irqs[SCIx_BRI_IRQ]) {
                /* Break and Error interrupts are muxed */
                unsigned short ssr_status = serial_port_in(port, SCxSR);

                /* Break Interrupt */
                if (ssr_status & SCxSR_BRK(port))
                        sci_br_interrupt(irq, ptr);

                /* Break only? */
                if (!(ssr_status & SCxSR_ERRORS(port)))
                        return IRQ_HANDLED;
        }

        /* Handle errors */
        if (port->type == PORT_SCI) {
                if (sci_handle_errors(port)) {
                        /* discard character in rx buffer */
                        serial_port_in(port, SCxSR);
                        sci_clear_SCxSR(port, SCxSR_RDxF_CLEAR(port));
                }
        } else {
                sci_handle_fifo_overrun(port);
                if (!s->chan_rx)
                        sci_receive_chars(ptr);
        }

        sci_clear_SCxSR(port, SCxSR_ERROR_CLEAR(port));

        /* Kick the transmission */
        if (!s->chan_tx)
                sci_tx_interrupt(irq, ptr);

        return IRQ_HANDLED;
}

static irqreturn_t sci_mpxed_interrupt(int irq, void *ptr)
{
        unsigned short ssr_status, scr_status, err_enabled, orer_status = 0;
        struct uart_port *port = ptr;
        struct sci_port *s = to_sci_port(port);
        irqreturn_t ret = IRQ_NONE;

        ssr_status = serial_port_in(port, SCxSR);
        scr_status = serial_port_in(port, SCSCR);
        if (s->params->overrun_reg == SCxSR)
                orer_status = ssr_status;
        else if (sci_getreg(port, s->params->overrun_reg)->size)
                orer_status = serial_port_in(port, s->params->overrun_reg);

        err_enabled = scr_status & port_rx_irq_mask(port);

        /* Tx Interrupt */
        if ((ssr_status & SCxSR_TDxE(port)) && (scr_status & SCSCR_TIE) &&
            !s->chan_tx)
                ret = sci_tx_interrupt(irq, ptr);

        /*
         * Rx Interrupt: if we're using DMA, the DMA controller clears RDF /
         * DR flags
         */
        if (((ssr_status & SCxSR_RDxF(port)) || s->chan_rx) &&
            (scr_status & SCSCR_RIE))
                ret = sci_rx_interrupt(irq, ptr);

        /* Error Interrupt */
        if ((ssr_status & SCxSR_ERRORS(port)) && err_enabled)
                ret = sci_er_interrupt(irq, ptr);

        /* Break Interrupt */
        if ((ssr_status & SCxSR_BRK(port)) && err_enabled)
                ret = sci_br_interrupt(irq, ptr);

        /* Overrun Interrupt */
        if (orer_status & s->params->overrun_mask) {
                sci_handle_fifo_overrun(port);
                ret = IRQ_HANDLED;
        }

        return ret;
}

static const struct sci_irq_desc {
        const char      *desc;
        irq_handler_t   handler;
} sci_irq_desc[] = {
        /*
         * Split out handlers, the default case.
         */
        [SCIx_ERI_IRQ] = {
                .desc = "rx err",
                .handler = sci_er_interrupt,
        },

        [SCIx_RXI_IRQ] = {
                .desc = "rx full",
                .handler = sci_rx_interrupt,
        },

        [SCIx_TXI_IRQ] = {
                .desc = "tx empty",
                .handler = sci_tx_interrupt,
        },

        [SCIx_BRI_IRQ] = {
                .desc = "break",
                .handler = sci_br_interrupt,
        },

        [SCIx_DRI_IRQ] = {
                .desc = "rx ready",
                .handler = sci_rx_interrupt,
        },

        [SCIx_TEI_IRQ] = {
                .desc = "tx end",
                .handler = sci_tx_interrupt,
        },

        /*
         * Special muxed handler.
         */
        [SCIx_MUX_IRQ] = {
                .desc = "mux",
                .handler = sci_mpxed_interrupt,
        },
};

static int sci_request_irq(struct sci_port *port)
{
        struct uart_port *up = &port->port;
        int i, j, w, ret = 0;

        for (i = j = 0; i < SCIx_NR_IRQS; i++, j++) {
                const struct sci_irq_desc *desc;
                int irq;

                /* Check if already registered (muxed) */
                for (w = 0; w < i; w++)
                        if (port->irqs[w] == port->irqs[i])
                                w = i + 1;
                if (w > i)
                        continue;

                if (SCIx_IRQ_IS_MUXED(port)) {
                        i = SCIx_MUX_IRQ;
                        irq = up->irq;
                } else {
                        irq = port->irqs[i];

                        /*
                         * Certain port types won't support all of the
                         * available interrupt sources.
                         */
                        if (unlikely(irq < 0))
                                continue;
                }

                desc = sci_irq_desc + i;
                port->irqstr[j] = kasprintf(GFP_KERNEL, "%s:%s",
                                            dev_name(up->dev), desc->desc);
                if (!port->irqstr[j]) {
                        ret = -ENOMEM;
                        goto out_nomem;
                }

                ret = request_irq(irq, desc->handler, up->irqflags,
                                  port->irqstr[j], port);
                if (unlikely(ret)) {
                        dev_err(up->dev, "Can't allocate %s IRQ\n", desc->desc);
                        goto out_noirq;
                }
        }

        return 0;

out_noirq:
        while (--i >= 0)
                free_irq(port->irqs[i], port);

out_nomem:
        while (--j >= 0)
                kfree(port->irqstr[j]);

        return ret;
}

static void sci_free_irq(struct sci_port *port)
{
        int i;

        /*
         * Intentionally in reverse order so we iterate over the muxed
         * IRQ first.
         */
        for (i = 0; i < SCIx_NR_IRQS; i++) {
                int irq = port->irqs[i];

                /*
                 * Certain port types won't support all of the available
                 * interrupt sources.
                 */
                if (unlikely(irq < 0))
                        continue;

                free_irq(port->irqs[i], port);
                kfree(port->irqstr[i]);

                if (SCIx_IRQ_IS_MUXED(port)) {
                        /* If there's only one IRQ, we're done. */
                        return;
                }
        }
}

static unsigned int sci_tx_empty(struct uart_port *port)
{
        unsigned short status = serial_port_in(port, SCxSR);
        unsigned short in_tx_fifo = sci_txfill(port);

        return (status & SCxSR_TEND(port)) && !in_tx_fifo ? TIOCSER_TEMT : 0;
}

static void sci_set_rts(struct uart_port *port, bool state)
{
        if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) {
                u16 data = serial_port_in(port, SCPDR);

                /* Active low */
                if (state)
                        data &= ~SCPDR_RTSD;
                else
                        data |= SCPDR_RTSD;
                serial_port_out(port, SCPDR, data);

                /* RTS# is output */
                serial_port_out(port, SCPCR,
                                serial_port_in(port, SCPCR) | SCPCR_RTSC);
        } else if (sci_getreg(port, SCSPTR)->size) {
                u16 ctrl = serial_port_in(port, SCSPTR);

                /* Active low */
                if (state)
                        ctrl &= ~SCSPTR_RTSDT;
                else
                        ctrl |= SCSPTR_RTSDT;
                serial_port_out(port, SCSPTR, ctrl);
        }
}

static bool sci_get_cts(struct uart_port *port)
{
        if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) {
                /* Active low */
                return !(serial_port_in(port, SCPDR) & SCPDR_CTSD);
        } else if (sci_getreg(port, SCSPTR)->size) {
                /* Active low */
                return !(serial_port_in(port, SCSPTR) & SCSPTR_CTSDT);
        }

        return true;
}

/*
 * Modem control is a bit of a mixed bag for SCI(F) ports. Generally
 * CTS/RTS is supported in hardware by at least one port and controlled
 * via SCSPTR (SCxPCR for SCIFA/B parts), or external pins (presently
 * handled via the ->init_pins() op, which is a bit of a one-way street,
 * lacking any ability to defer pin control -- this will later be
 * converted over to the GPIO framework).
 *
 * Other modes (such as loopback) are supported generically on certain
 * port types, but not others. For these it's sufficient to test for the

 * existence of the support register and simply ignore the port type.
 */
static void sci_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        struct sci_port *s = to_sci_port(port);

        if (mctrl & TIOCM_LOOP) {
                const struct plat_sci_reg *reg;

                /*
                 * Standard loopback mode for SCFCR ports.
                 */
                reg = sci_getreg(port, SCFCR);
                if (reg->size)
                        serial_port_out(port, SCFCR,
                                        serial_port_in(port, SCFCR) |
                                        SCFCR_LOOP);
        }

        mctrl_gpio_set(s->gpios, mctrl);

        if (!s->has_rtscts)
                return;

        if (!(mctrl & TIOCM_RTS)) {
                /* Disable Auto RTS */
                serial_port_out(port, SCFCR,
                                serial_port_in(port, SCFCR) & ~SCFCR_MCE);

                /* Clear RTS */
                sci_set_rts(port, 0);
        } else if (s->autorts) {
                if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) {
                        /* Enable RTS# pin function */
                        serial_port_out(port, SCPCR,
                                serial_port_in(port, SCPCR) & ~SCPCR_RTSC);
                }

                /* Enable Auto RTS */
                serial_port_out(port, SCFCR,
                                serial_port_in(port, SCFCR) | SCFCR_MCE);
        } else {
                /* Set RTS */
                sci_set_rts(port, 1);
        }
}

static unsigned int sci_get_mctrl(struct uart_port *port)
{
        struct sci_port *s = to_sci_port(port);
        struct mctrl_gpios *gpios = s->gpios;
        unsigned int mctrl = 0;

        mctrl_gpio_get(gpios, &mctrl);

        /*
         * CTS/RTS is handled in hardware when supported, while nothing
         * else is wired up.
         */
        if (s->autorts) {
                if (sci_get_cts(port))
                        mctrl |= TIOCM_CTS;
        } else if (IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(gpios, UART_GPIO_CTS))) {
                mctrl |= TIOCM_CTS;
        }
        if (IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(gpios, UART_GPIO_DSR)))
                mctrl |= TIOCM_DSR;
        if (IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(gpios, UART_GPIO_DCD)))
                mctrl |= TIOCM_CAR;

        return mctrl;
}

static void sci_enable_ms(struct uart_port *port)
{
        mctrl_gpio_enable_ms(to_sci_port(port)->gpios);
}

static void sci_break_ctl(struct uart_port *port, int break_state)
{
        unsigned short scscr, scsptr;
        unsigned long flags;

        /* check wheter the port has SCSPTR */
        if (!sci_getreg(port, SCSPTR)->size) {
                /*
                 * Not supported by hardware. Most parts couple break and rx
                 * interrupts together, with break detection always enabled.
                 */
                return;
        }

        spin_lock_irqsave(&port->lock, flags);
        scsptr = serial_port_in(port, SCSPTR);
        scscr = serial_port_in(port, SCSCR);

        if (break_state == -1) {
                scsptr = (scsptr | SCSPTR_SPB2IO) & ~SCSPTR_SPB2DT;
                scscr &= ~SCSCR_TE;
        } else {
                scsptr = (scsptr | SCSPTR_SPB2DT) & ~SCSPTR_SPB2IO;
                scscr |= SCSCR_TE;
        }

        serial_port_out(port, SCSPTR, scsptr);
        serial_port_out(port, SCSCR, scscr);
        spin_unlock_irqrestore(&port->lock, flags);
}

static int sci_startup(struct uart_port *port)
{
        struct sci_port *s = to_sci_port(port);
        int ret;

        dev_dbg(port->dev, "%s(%d)\n", __func__, port->line);

        sci_request_dma(port);

        ret = sci_request_irq(s);
        if (unlikely(ret < 0)) {
                sci_free_dma(port);
                return ret;
        }

        return 0;
}

static void sci_shutdown(struct uart_port *port)
{
        struct sci_port *s = to_sci_port(port);
        unsigned long flags;
        u16 scr;

        dev_dbg(port->dev, "%s(%d)\n", __func__, port->line);

        s->autorts = false;
        mctrl_gpio_disable_ms(to_sci_port(port)->gpios);

        spin_lock_irqsave(&port->lock, flags);
        sci_stop_rx(port);
        sci_stop_tx(port);
        /*
         * Stop RX and TX, disable related interrupts, keep clock source
         * and HSCIF TOT bits
         */
        scr = serial_port_in(port, SCSCR);
        serial_port_out(port, SCSCR, scr &
                        (SCSCR_CKE1 | SCSCR_CKE0 | s->hscif_tot));
        spin_unlock_irqrestore(&port->lock, flags);

#ifdef CONFIG_SERIAL_SH_SCI_DMA
        if (s->chan_rx_saved) {
                dev_dbg(port->dev, "%s(%d) deleting rx_timer\n", __func__,
                        port->line);
                hrtimer_cancel(&s->rx_timer);
        }
#endif

        if (s->rx_trigger > 1 && s->rx_fifo_timeout > 0)
                del_timer_sync(&s->rx_fifo_timer);
        sci_free_irq(s);
        sci_free_dma(port);
}

static int sci_sck_calc(struct sci_port *s, unsigned int bps,
                        unsigned int *srr)
{
        unsigned long freq = s->clk_rates[SCI_SCK];
        int err, min_err = INT_MAX;
        unsigned int sr;

        if (s->port.type != PORT_HSCIF)
                freq *= 2;

        for_each_sr(sr, s) {
                err = DIV_ROUND_CLOSEST(freq, sr) - bps;
                if (abs(err) >= abs(min_err))
                        continue;

                min_err = err;
                *srr = sr - 1;

                if (!err)
                        break;
        }

        dev_dbg(s->port.dev, "SCK: %u%+d bps using SR %u\n", bps, min_err,
                *srr + 1);
        return min_err;
}

static int sci_brg_calc(struct sci_port *s, unsigned int bps,
                        unsigned long freq, unsigned int *dlr,
                        unsigned int *srr)
{
        int err, min_err = INT_MAX;
        unsigned int sr, dl;

        if (s->port.type != PORT_HSCIF)
                freq *= 2;

        for_each_sr(sr, s) {
                dl = DIV_ROUND_CLOSEST(freq, sr * bps);
                dl = clamp(dl, 1U, 65535U);

                err = DIV_ROUND_CLOSEST(freq, sr * dl) - bps;
                if (abs(err) >= abs(min_err))
                        continue;

                min_err = err;
                *dlr = dl;
                *srr = sr - 1;

                if (!err)
                        break;
        }

        dev_dbg(s->port.dev, "BRG: %u%+d bps using DL %u SR %u\n", bps,
                min_err, *dlr, *srr + 1);
        return min_err;
}

/* calculate sample rate, BRR, and clock select */
static int sci_scbrr_calc(struct sci_port *s, unsigned int bps,
                          unsigned int *brr, unsigned int *srr,
                          unsigned int *cks)
{
        unsigned long freq = s->clk_rates[SCI_FCK];
        unsigned int sr, br, prediv, scrate, c;
        int err, min_err = INT_MAX;

        if (s->port.type != PORT_HSCIF)
                freq *= 2;

        /*
         * Find the combination of sample rate and clock select with the
         * smallest deviation from the desired baud rate.
         * Prefer high sample rates to maximise the receive margin.
         *
         * M: Receive margin (%)
         * N: Ratio of bit rate to clock (N = sampling rate)
         * D: Clock duty (D = 0 to 1.0)
         * L: Frame length (L = 9 to 12)
         * F: Absolute value of clock frequency deviation
         *
         *  M = |(0.5 - 1 / 2 * N) - ((L - 0.5) * F) -
         *      (|D - 0.5| / N * (1 + F))|
         *  NOTE: Usually, treat D for 0.5, F is 0 by this calculation.
         */
        for_each_sr(sr, s) {
                for (c = 0; c <= 3; c++) {
                        /* integerized formulas from HSCIF documentation */
                        prediv = sr * (1 << (2 * c + 1));

                        /*
                         * We need to calculate:
                         *
                         *     br = freq / (prediv * bps) clamped to [1..256]
                         *     err = freq / (br * prediv) - bps
                         *
                         * Watch out for overflow when calculating the desired
                         * sampling clock rate!
                         */
                        if (bps > UINT_MAX / prediv)
                                break;

                        scrate = prediv * bps;
                        br = DIV_ROUND_CLOSEST(freq, scrate);
                        br = clamp(br, 1U, 256U);

                        err = DIV_ROUND_CLOSEST(freq, br * prediv) - bps;
                        if (abs(err) >= abs(min_err))
                                continue;

                        min_err = err;
                        *brr = br - 1;
                        *srr = sr - 1;
                        *cks = c;

                        if (!err)
                                goto found;
                }
        }

found:
        dev_dbg(s->port.dev, "BRR: %u%+d bps using N %u SR %u cks %u\n", bps,
                min_err, *brr, *srr + 1, *cks);
        return min_err;
}

static void sci_reset(struct uart_port *port)
{
        const struct plat_sci_reg *reg;
        unsigned int status;
        struct sci_port *s = to_sci_port(port);

        serial_port_out(port, SCSCR, s->hscif_tot);     /* TE=0, RE=0, CKE1=0 */

        reg = sci_getreg(port, SCFCR);
        if (reg->size)
                serial_port_out(port, SCFCR, SCFCR_RFRST | SCFCR_TFRST);

        sci_clear_SCxSR(port,
                        SCxSR_RDxF_CLEAR(port) & SCxSR_ERROR_CLEAR(port) &
                        SCxSR_BREAK_CLEAR(port));
        if (sci_getreg(port, SCLSR)->size) {
                status = serial_port_in(port, SCLSR);
                status &= ~(SCLSR_TO | SCLSR_ORER);
                serial_port_out(port, SCLSR, status);
        }

        if (s->rx_trigger > 1) {
                if (s->rx_fifo_timeout) {
                        scif_set_rtrg(port, 1);
                        timer_setup(&s->rx_fifo_timer, rx_fifo_timer_fn, 0);
                } else {
                        if (port->type == PORT_SCIFA ||
                            port->type == PORT_SCIFB)
                                scif_set_rtrg(port, 1);
                        else
                                scif_set_rtrg(port, s->rx_trigger);
                }
        }
}

static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
                            struct ktermios *old)
{
        unsigned int baud, smr_val = SCSMR_ASYNC, scr_val = 0, i, bits;
        unsigned int brr = 255, cks = 0, srr = 15, dl = 0, sccks = 0;
        unsigned int brr1 = 255, cks1 = 0, srr1 = 15, dl1 = 0;
        struct sci_port *s = to_sci_port(port);
        const struct plat_sci_reg *reg;
        int min_err = INT_MAX, err;
        unsigned long max_freq = 0;
        int best_clk = -1;
        unsigned long flags;

        if ((termios->c_cflag & CSIZE) == CS7)
                smr_val |= SCSMR_CHR;
        if (termios->c_cflag & PARENB)
                smr_val |= SCSMR_PE;
        if (termios->c_cflag & PARODD)
                smr_val |= SCSMR_PE | SCSMR_ODD;
        if (termios->c_cflag & CSTOPB)
                smr_val |= SCSMR_STOP;

        /*
         * earlyprintk comes here early on with port->uartclk set to zero.
         * the clock framework is not up and running at this point so here
         * we assume that 115200 is the maximum baud rate. please note that
         * the baud rate is not programmed during earlyprintk - it is assumed
         * that the previous boot loader has enabled required clocks and
         * setup the baud rate generator hardware for us already.
         */
        if (!port->uartclk) {
                baud = uart_get_baud_rate(port, termios, old, 0, 115200);
                goto done;
        }

        for (i = 0; i < SCI_NUM_CLKS; i++)
                max_freq = max(max_freq, s->clk_rates[i]);

        baud = uart_get_baud_rate(port, termios, old, 0, max_freq / min_sr(s));
        if (!baud)
                goto done;

        /*
         * There can be multiple sources for the sampling clock.  Find the one
         * that gives us the smallest deviation from the desired baud rate.
         */

        /* Optional Undivided External Clock */
        if (s->clk_rates[SCI_SCK] && port->type != PORT_SCIFA &&
            port->type != PORT_SCIFB) {
                err = sci_sck_calc(s, baud, &srr1);
                if (abs(err) < abs(min_err)) {
                        best_clk = SCI_SCK;
                        scr_val = SCSCR_CKE1;
                        sccks = SCCKS_CKS;
                        min_err = err;
                        srr = srr1;
                        if (!err)
                                goto done;
                }
        }

        /* Optional BRG Frequency Divided External Clock */
        if (s->clk_rates[SCI_SCIF_CLK] && sci_getreg(port, SCDL)->size) {
                err = sci_brg_calc(s, baud, s->clk_rates[SCI_SCIF_CLK], &dl1,
                                   &srr1);
                if (abs(err) < abs(min_err)) {
                        best_clk = SCI_SCIF_CLK;
                        scr_val = SCSCR_CKE1;
                        sccks = 0;
                        min_err = err;
                        dl = dl1;
                        srr = srr1;
                        if (!err)
                                goto done;
                }
        }

        /* Optional BRG Frequency Divided Internal Clock */
        if (s->clk_rates[SCI_BRG_INT] && sci_getreg(port, SCDL)->size) {
                err = sci_brg_calc(s, baud, s->clk_rates[SCI_BRG_INT], &dl1,
                                   &srr1);
                if (abs(err) < abs(min_err)) {
                        best_clk = SCI_BRG_INT;
                        scr_val = SCSCR_CKE1;
                        sccks = SCCKS_XIN;
                        min_err = err;
                        dl = dl1;
                        srr = srr1;
                        if (!min_err)
                                goto done;
                }
        }

        /* Divided Functional Clock using standard Bit Rate Register */
        err = sci_scbrr_calc(s, baud, &brr1, &srr1, &cks1);
        if (abs(err) < abs(min_err)) {
                best_clk = SCI_FCK;
                scr_val = 0;
                min_err = err;
                brr = brr1;
                srr = srr1;
                cks = cks1;
        }

done:
        if (best_clk >= 0)
                dev_dbg(port->dev, "Using clk %pC for %u%+d bps\n",
                        s->clks[best_clk], baud, min_err);

        sci_port_enable(s);

        /*
         * Program the optional External Baud Rate Generator (BRG) first.
         * It controls the mux to select (H)SCK or frequency divided clock.
         */
        if (best_clk >= 0 && sci_getreg(port, SCCKS)->size) {
                serial_port_out(port, SCDL, dl);
                serial_port_out(port, SCCKS, sccks);
        }

        spin_lock_irqsave(&port->lock, flags);

        sci_reset(port);

        uart_update_timeout(port, termios->c_cflag, baud);

        /* byte size and parity */
        switch (termios->c_cflag & CSIZE) {
        case CS5:
                bits = 7;
                break;
        case CS6:
                bits = 8;
                break;
        case CS7:
                bits = 9;
                break;
        default:
                bits = 10;
                break;
        }

        if (termios->c_cflag & CSTOPB)
                bits++;
        if (termios->c_cflag & PARENB)
                bits++;

        if (best_clk >= 0) {
                if (port->type == PORT_SCIFA || port->type == PORT_SCIFB)
                        switch (srr + 1) {
                        case 5:  smr_val |= SCSMR_SRC_5;  break;
                        case 7:  smr_val |= SCSMR_SRC_7;  break;
                        case 11: smr_val |= SCSMR_SRC_11; break;
                        case 13: smr_val |= SCSMR_SRC_13; break;
                        case 16: smr_val |= SCSMR_SRC_16; break;
                        case 17: smr_val |= SCSMR_SRC_17; break;
                        case 19: smr_val |= SCSMR_SRC_19; break;
                        case 27: smr_val |= SCSMR_SRC_27; break;
                        }
                smr_val |= cks;
                serial_port_out(port, SCSCR, scr_val | s->hscif_tot);
                serial_port_out(port, SCSMR, smr_val);
                serial_port_out(port, SCBRR, brr);
                if (sci_getreg(port, HSSRR)->size) {
                        unsigned int hssrr = srr | HSCIF_SRE;
                        /* Calculate deviation from intended rate at the
                         * center of the last stop bit in sampling clocks.
                         */
                        int last_stop = bits * 2 - 1;
                        int deviation = min_err * srr * last_stop / 2 / baud;

                        if (abs(deviation) >= 2) {
                                /* At least two sampling clocks off at the
                                 * last stop bit; we can increase the error
                                 * margin by shifting the sampling point.
                                 */
                                int shift = min(-8, max(7, deviation / 2));

                                hssrr |= (shift << HSCIF_SRHP_SHIFT) &
                                         HSCIF_SRHP_MASK;
                                hssrr |= HSCIF_SRDE;
                        }
                        serial_port_out(port, HSSRR, hssrr);
                }

                /* Wait one bit interval */
                udelay((1000000 + (baud - 1)) / baud);
        } else {
                /* Don't touch the bit rate configuration */
                scr_val = s->cfg->scscr & (SCSCR_CKE1 | SCSCR_CKE0);
                smr_val |= serial_port_in(port, SCSMR) &
                           (SCSMR_CKEDG | SCSMR_SRC_MASK | SCSMR_CKS);
                serial_port_out(port, SCSCR, scr_val | s->hscif_tot);
                serial_port_out(port, SCSMR, smr_val);
        }

        sci_init_pins(port, termios->c_cflag);

        port->status &= ~UPSTAT_AUTOCTS;
        s->autorts = false;
        reg = sci_getreg(port, SCFCR);
        if (reg->size) {
                unsigned short ctrl = serial_port_in(port, SCFCR);

                if ((port->flags & UPF_HARD_FLOW) &&
                    (termios->c_cflag & CRTSCTS)) {
                        /* There is no CTS interrupt to restart the hardware */
                        port->status |= UPSTAT_AUTOCTS;
                        /* MCE is enabled when RTS is raised */
                        s->autorts = true;
                }

                /*
                 * As we've done a sci_reset() above, ensure we don't
                 * interfere with the FIFOs while toggling MCE. As the
                 * reset values could still be set, simply mask them out.
                 */
                ctrl &= ~(SCFCR_RFRST | SCFCR_TFRST);

                serial_port_out(port, SCFCR, ctrl);
        }
        if (port->flags & UPF_HARD_FLOW) {
                /* Refresh (Auto) RTS */
                sci_set_mctrl(port, port->mctrl);
        }

        scr_val |= SCSCR_RE | SCSCR_TE |
                   (s->cfg->scscr & ~(SCSCR_CKE1 | SCSCR_CKE0));
        serial_port_out(port, SCSCR, scr_val | s->hscif_tot);
        if ((srr + 1 == 5) &&
            (port->type == PORT_SCIFA || port->type == PORT_SCIFB)) {
                /*
                 * In asynchronous mode, when the sampling rate is 1/5, first
                 * received data may become invalid on some SCIFA and SCIFB.
                 * To avoid this problem wait more than 1 serial data time (1
                 * bit time x serial data number) after setting SCSCR.RE = 1.
                 */
                udelay(DIV_ROUND_UP(10 * 1000000, baud));
        }

        /*
         * Calculate delay for 2 DMA buffers (4 FIFO).
         * See serial_core.c::uart_update_timeout().
         * With 10 bits (CS8), 250Hz, 115200 baud and 64 bytes FIFO, the above
         * function calculates 1 jiffie for the data plus 5 jiffies for the
         * "slop(e)." Then below we calculate 5 jiffies (20ms) for 2 DMA
         * buffers (4 FIFO sizes), but when performing a faster transfer, the
         * value obtained by this formula is too small. Therefore, if the value
         * is smaller than 20ms, use 20ms as the timeout value for DMA.
         */
        s->rx_frame = (10000 * bits) / (baud / 100);
#ifdef CONFIG_SERIAL_SH_SCI_DMA
        s->rx_timeout = s->buf_len_rx * 2 * s->rx_frame;
        if (s->rx_timeout < 20)
                s->rx_timeout = 20;
#endif

        if ((termios->c_cflag & CREAD) != 0)
                sci_start_rx(port);

        spin_unlock_irqrestore(&port->lock, flags);

        sci_port_disable(s);

        if (UART_ENABLE_MS(port, termios->c_cflag))
                sci_enable_ms(port);
}

static void sci_pm(struct uart_port *port, unsigned int state,
                   unsigned int oldstate)
{
        struct sci_port *sci_port = to_sci_port(port);

        switch (state) {
        case UART_PM_STATE_OFF:
                sci_port_disable(sci_port);
                break;
        default:
                sci_port_enable(sci_port);
                break;
        }
}

static const char *sci_type(struct uart_port *port)
{
        switch (port->type) {
        case PORT_IRDA:
                return "irda";
        case PORT_SCI:
                return "sci";
        case PORT_SCIF:
                return "scif";
        case PORT_SCIFA:
                return "scifa";
        case PORT_SCIFB:
                return "scifb";
        case PORT_HSCIF:
                return "hscif";
        }

        return NULL;
}

static int sci_remap_port(struct uart_port *port)
{
        struct sci_port *sport = to_sci_port(port);

        /*
         * Nothing to do if there's already an established membase.
         */
        if (port->membase)
                return 0;

        if (port->dev->of_node || (port->flags & UPF_IOREMAP)) {
                port->membase = ioremap_nocache(port->mapbase, sport->reg_size);
                if (unlikely(!port->membase)) {
                        dev_err(port->dev, "can't remap port#%d\n", port->line);
                        return -ENXIO;
                }
        } else {
                /*
                 * For the simple (and majority of) cases where we don't
                 * need to do any remapping, just cast the cookie
                 * directly.
                 */
                port->membase = (void __iomem *)(uintptr_t)port->mapbase;
        }

        return 0;
}

static void sci_release_port(struct uart_port *port)
{
        struct sci_port *sport = to_sci_port(port);

        if (port->dev->of_node || (port->flags & UPF_IOREMAP)) {
                iounmap(port->membase);
                port->membase = NULL;
        }

        release_mem_region(port->mapbase, sport->reg_size);
}

static int sci_request_port(struct uart_port *port)
{
        struct resource *res;
        struct sci_port *sport = to_sci_port(port);
        int ret;

        res = request_mem_region(port->mapbase, sport->reg_size,
                                 dev_name(port->dev));
        if (unlikely(res == NULL)) {
                dev_err(port->dev, "request_mem_region failed.");
                return -EBUSY;
        }

        ret = sci_remap_port(port);
        if (unlikely(ret != 0)) {
                release_resource(res);
                return ret;
        }

        return 0;
}

static void sci_config_port(struct uart_port *port, int flags)
{
        if (flags & UART_CONFIG_TYPE) {
                struct sci_port *sport = to_sci_port(port);

                port->type = sport->cfg->type;
                sci_request_port(port);
        }
}

static int sci_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        if (ser->baud_base < 2400)
                /* No paper tape reader for Mitch.. */
                return -EINVAL;

        return 0;
}

static const struct uart_ops sci_uart_ops = {
        .tx_empty       = sci_tx_empty,
        .set_mctrl      = sci_set_mctrl,
        .get_mctrl      = sci_get_mctrl,
        .start_tx       = sci_start_tx,
        .stop_tx        = sci_stop_tx,
        .stop_rx        = sci_stop_rx,
        .enable_ms      = sci_enable_ms,
        .break_ctl      = sci_break_ctl,
        .startup        = sci_startup,
        .shutdown       = sci_shutdown,
        .flush_buffer   = sci_flush_buffer,
        .set_termios    = sci_set_termios,
        .pm             = sci_pm,
        .type           = sci_type,
        .release_port   = sci_release_port,
        .request_port   = sci_request_port,
        .config_port    = sci_config_port,
        .verify_port    = sci_verify_port,
#ifdef CONFIG_CONSOLE_POLL
        .poll_get_char  = sci_poll_get_char,
        .poll_put_char  = sci_poll_put_char,
#endif
};

static int sci_init_clocks(struct sci_port *sci_port, struct device *dev)
{
        const char *clk_names[] = {
                [SCI_FCK] = "fck",
                [SCI_SCK] = "sck",
                [SCI_BRG_INT] = "brg_int",
                [SCI_SCIF_CLK] = "scif_clk",
        };
        struct clk *clk;
        unsigned int i;

        if (sci_port->cfg->type == PORT_HSCIF)
                clk_names[SCI_SCK] = "hsck";

        for (i = 0; i < SCI_NUM_CLKS; i++) {
                clk = devm_clk_get(dev, clk_names[i]);
                if (PTR_ERR(clk) == -EPROBE_DEFER)
                        return -EPROBE_DEFER;

                if (IS_ERR(clk) && i == SCI_FCK) {
                        /*
                         * "fck" used to be called "sci_ick", and we need to
                         * maintain DT backward compatibility.
                         */
                        clk = devm_clk_get(dev, "sci_ick");
                        if (PTR_ERR(clk) == -EPROBE_DEFER)
                                return -EPROBE_DEFER;

                        if (!IS_ERR(clk))
                                goto found;

                        /*
                         * Not all SH platforms declare a clock lookup entry
                         * for SCI devices, in which case we need to get the
                         * global "peripheral_clk" clock.
                         */
                        clk = devm_clk_get(dev, "peripheral_clk");
                        if (!IS_ERR(clk))
                                goto found;

                        dev_err(dev, "failed to get %s (%ld)\n", clk_names[i],
                                PTR_ERR(clk));
                        return PTR_ERR(clk);
                }

found:
                if (IS_ERR(clk))
                        dev_dbg(dev, "failed to get %s (%ld)\n", clk_names[i],
                                PTR_ERR(clk));
                else
                        dev_dbg(dev, "clk %s is %pC rate %lu\n", clk_names[i],
                                clk, clk_get_rate(clk));
                sci_port->clks[i] = IS_ERR(clk) ? NULL : clk;
        }
        return 0;
}

static const struct sci_port_params *
sci_probe_regmap(const struct plat_sci_port *cfg)
{
        unsigned int regtype;

        if (cfg->regtype != SCIx_PROBE_REGTYPE)
                return &sci_port_params[cfg->regtype];

        switch (cfg->type) {
        case PORT_SCI:
                regtype = SCIx_SCI_REGTYPE;
                break;
        case PORT_IRDA:
                regtype = SCIx_IRDA_REGTYPE;
                break;
        case PORT_SCIFA:
                regtype = SCIx_SCIFA_REGTYPE;
                break;
        case PORT_SCIFB:
                regtype = SCIx_SCIFB_REGTYPE;
                break;
        case PORT_SCIF:
                /*
                 * The SH-4 is a bit of a misnomer here, although that's
                 * where this particular port layout originated. This
                 * configuration (or some slight variation thereof)
                 * remains the dominant model for all SCIFs.
                 */
                regtype = SCIx_SH4_SCIF_REGTYPE;
                break;
        case PORT_HSCIF:
                regtype = SCIx_HSCIF_REGTYPE;
                break;
        default:
                pr_err("Can't probe register map for given port\n");
                return NULL;
        }

        return &sci_port_params[regtype];
}

static int sci_init_single(struct platform_device *dev,
                           struct sci_port *sci_port, unsigned int index,
                           const struct plat_sci_port *p, bool early)
{
        struct uart_port *port = &sci_port->port;
        const struct resource *res;
        unsigned int i;
        int ret;

        sci_port->cfg   = p;

        port->ops       = &sci_uart_ops;
        port->iotype    = UPIO_MEM;
        port->line      = index;

        res = platform_get_resource(dev, IORESOURCE_MEM, 0);
        if (res == NULL)
                return -ENOMEM;

        port->mapbase = res->start;
        sci_port->reg_size = resource_size(res);

        for (i = 0; i < ARRAY_SIZE(sci_port->irqs); ++i)
                sci_port->irqs[i] = platform_get_irq(dev, i);

        /* The SCI generates several interrupts. They can be muxed together or
         * connected to different interrupt lines. In the muxed case only one
         * interrupt resource is specified as there is only one interrupt ID.
         * In the non-muxed case, up to 6 interrupt signals might be generated
         * from the SCI, however those signals might have their own individual
         * interrupt ID numbers, or muxed together with another interrupt.
         */
        if (sci_port->irqs[0] < 0)
                return -ENXIO;

        if (sci_port->irqs[1] < 0)
                for (i = 1; i < ARRAY_SIZE(sci_port->irqs); i++)
                        sci_port->irqs[i] = sci_port->irqs[0];

        sci_port->params = sci_probe_regmap(p);
        if (unlikely(sci_port->params == NULL))
                return -EINVAL;

        switch (p->type) {
        case PORT_SCIFB:
                sci_port->rx_trigger = 48;
                break;
        case PORT_HSCIF:
                sci_port->rx_trigger = 64;
                break;
        case PORT_SCIFA:
                sci_port->rx_trigger = 32;
                break;
        case PORT_SCIF:
                if (p->regtype == SCIx_SH7705_SCIF_REGTYPE)
                        /* RX triggering not implemented for this IP */
                        sci_port->rx_trigger = 1;
                else
                        sci_port->rx_trigger = 8;
                break;
        default:
                sci_port->rx_trigger = 1;
                break;
        }

        sci_port->rx_fifo_timeout = 0;
        sci_port->hscif_tot = 0;

        /* SCIFA on sh7723 and sh7724 need a custom sampling rate that doesn't
         * match the SoC datasheet, this should be investigated. Let platform
         * data override the sampling rate for now.
         */
        sci_port->sampling_rate_mask = p->sampling_rate
                                     ? SCI_SR(p->sampling_rate)
                                     : sci_port->params->sampling_rate_mask;

        if (!early) {
                ret = sci_init_clocks(sci_port, &dev->dev);
                if (ret < 0)
                        return ret;

                port->dev = &dev->dev;

                pm_runtime_enable(&dev->dev);
        }

        port->type              = p->type;
        port->flags             = UPF_FIXED_PORT | UPF_BOOT_AUTOCONF | p->flags;
        port->fifosize          = sci_port->params->fifosize;

        if (port->type == PORT_SCI) {
                if (sci_port->reg_size >= 0x20)
                        port->regshift = 2;
                else
                        port->regshift = 1;
        }

        /*
         * The UART port needs an IRQ value, so we peg this to the RX IRQ
         * for the multi-IRQ ports, which is where we are primarily
         * concerned with the shutdown path synchronization.
         *
         * For the muxed case there's nothing more to do.
         */
        port->irq               = sci_port->irqs[SCIx_RXI_IRQ];
        port->irqflags          = 0;

        port->serial_in         = sci_serial_in;
        port->serial_out        = sci_serial_out;

        return 0;
}

static void sci_cleanup_single(struct sci_port *port)
{
        pm_runtime_disable(port->port.dev);
}

#if defined(CONFIG_SERIAL_SH_SCI_CONSOLE) || \
    defined(CONFIG_SERIAL_SH_SCI_EARLYCON)
static void serial_console_putchar(struct uart_port *port, int ch)
{
        sci_poll_put_char(port, ch);
}

/*
 *      Print a string to the serial port trying not to disturb
 *      any possible real use of the port...
 */
static void serial_console_write(struct console *co, const char *s,
                                 unsigned count)
{
        struct sci_port *sci_port = &sci_ports[co->index];
        struct uart_port *port = &sci_port->port;
        unsigned short bits, ctrl, ctrl_temp;
        unsigned long flags;
        int locked = 1;

#if defined(SUPPORT_SYSRQ)
        if (port->sysrq)
                locked = 0;
        else
#endif
        if (oops_in_progress)
                locked = spin_trylock_irqsave(&port->lock, flags);
        else
                spin_lock_irqsave(&port->lock, flags);

        /* first save SCSCR then disable interrupts, keep clock source */
        ctrl = serial_port_in(port, SCSCR);
        ctrl_temp = SCSCR_RE | SCSCR_TE |
                    (sci_port->cfg->scscr & ~(SCSCR_CKE1 | SCSCR_CKE0)) |
                    (ctrl & (SCSCR_CKE1 | SCSCR_CKE0));
        serial_port_out(port, SCSCR, ctrl_temp | sci_port->hscif_tot);

        uart_console_write(port, s, count, serial_console_putchar);

        /* wait until fifo is empty and last bit has been transmitted */
        bits = SCxSR_TDxE(port) | SCxSR_TEND(port);
        while ((serial_port_in(port, SCxSR) & bits) != bits)
                cpu_relax();

        /* restore the SCSCR */
        serial_port_out(port, SCSCR, ctrl);

        if (locked)
                spin_unlock_irqrestore(&port->lock, flags);