root/drivers/tty/serial/mcf.c
// SPDX-License-Identifier: GPL-2.0+
/****************************************************************************/

/*
 *      mcf.c -- Freescale ColdFire UART driver
 *
 *      (C) Copyright 2003-2007, Greg Ungerer <gerg@uclinux.org>
 */

/****************************************************************************/

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/platform_device.h>
#include <asm/coldfire.h>
#include <asm/mcfsim.h>
#include <asm/mcfuart.h>
#include <asm/nettel.h>

/****************************************************************************/

/*
 *      Some boards implement the DTR/DCD lines using GPIO lines, most
 *      don't. Dummy out the access macros for those that don't. Those
 *      that do should define these macros somewhere in there board
 *      specific inlude files.
 */
#if !defined(mcf_getppdcd)
#define mcf_getppdcd(p)         (1)
#endif
#if !defined(mcf_getppdtr)
#define mcf_getppdtr(p)         (1)
#endif
#if !defined(mcf_setppdtr)
#define mcf_setppdtr(p, v)      do { } while (0)
#endif

/****************************************************************************/

/*
 *      Local per-uart structure.
 */
struct mcf_uart {
        struct uart_port        port;
        unsigned int            sigs;           /* Local copy of line sigs */
        unsigned char           imr;            /* Local IMR mirror */
};

/****************************************************************************/

static unsigned int mcf_tx_empty(struct uart_port *port)
{
        return (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXEMPTY) ?
                TIOCSER_TEMT : 0;
}

/****************************************************************************/

static unsigned int mcf_get_mctrl(struct uart_port *port)
{
        struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
        unsigned int sigs;

        sigs = (readb(port->membase + MCFUART_UIPR) & MCFUART_UIPR_CTS) ?
                0 : TIOCM_CTS;
        sigs |= (pp->sigs & TIOCM_RTS);
        sigs |= (mcf_getppdcd(port->line) ? TIOCM_CD : 0);
        sigs |= (mcf_getppdtr(port->line) ? TIOCM_DTR : 0);

        return sigs;
}

/****************************************************************************/

static void mcf_set_mctrl(struct uart_port *port, unsigned int sigs)
{
        struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

        pp->sigs = sigs;
        mcf_setppdtr(port->line, (sigs & TIOCM_DTR));
        if (sigs & TIOCM_RTS)
                writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP1);
        else
                writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP0);
}

/****************************************************************************/

static void mcf_start_tx(struct uart_port *port)
{
        struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

        if (port->rs485.flags & SER_RS485_ENABLED) {
                /* Enable Transmitter */
                writeb(MCFUART_UCR_TXENABLE, port->membase + MCFUART_UCR);
                /* Manually assert RTS */
                writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP1);
        }
        pp->imr |= MCFUART_UIR_TXREADY;
        writeb(pp->imr, port->membase + MCFUART_UIMR);
}

/****************************************************************************/

static void mcf_stop_tx(struct uart_port *port)
{
        struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

        pp->imr &= ~MCFUART_UIR_TXREADY;
        writeb(pp->imr, port->membase + MCFUART_UIMR);
}

/****************************************************************************/

static void mcf_stop_rx(struct uart_port *port)
{
        struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

        pp->imr &= ~MCFUART_UIR_RXREADY;
        writeb(pp->imr, port->membase + MCFUART_UIMR);
}

/****************************************************************************/

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

        uart_port_lock_irqsave(port, &flags);
        if (break_state == -1)
                writeb(MCFUART_UCR_CMDBREAKSTART, port->membase + MCFUART_UCR);
        else
                writeb(MCFUART_UCR_CMDBREAKSTOP, port->membase + MCFUART_UCR);
        uart_port_unlock_irqrestore(port, flags);
}

/****************************************************************************/

static int mcf_startup(struct uart_port *port)
{
        struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
        unsigned long flags;

        uart_port_lock_irqsave(port, &flags);

        /* Reset UART, get it into known state... */
        writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
        writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR);

        /* Enable the UART transmitter and receiver */
        writeb(MCFUART_UCR_RXENABLE | MCFUART_UCR_TXENABLE,
                port->membase + MCFUART_UCR);

        /* Enable RX interrupts now */
        pp->imr = MCFUART_UIR_RXREADY;
        writeb(pp->imr, port->membase + MCFUART_UIMR);

        uart_port_unlock_irqrestore(port, flags);

        return 0;
}

/****************************************************************************/

static void mcf_shutdown(struct uart_port *port)
{
        struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
        unsigned long flags;

        uart_port_lock_irqsave(port, &flags);

        /* Disable all interrupts now */
        pp->imr = 0;
        writeb(pp->imr, port->membase + MCFUART_UIMR);

        /* Disable UART transmitter and receiver */
        writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
        writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR);

        uart_port_unlock_irqrestore(port, flags);
}

/****************************************************************************/

static void mcf_set_termios(struct uart_port *port, struct ktermios *termios,
                            const struct ktermios *old)
{
        unsigned long flags;
        unsigned int baud, baudclk;
#if defined(CONFIG_M5272)
        unsigned int baudfr;
#endif
        unsigned char mr1, mr2;

        baud = uart_get_baud_rate(port, termios, old, 0, 230400);
#if defined(CONFIG_M5272)
        baudclk = (MCF_BUSCLK / baud) / 32;
        baudfr = (((MCF_BUSCLK / baud) + 1) / 2) % 16;
#else
        baudclk = ((MCF_BUSCLK / baud) + 16) / 32;
#endif

        mr1 = MCFUART_MR1_RXIRQRDY | MCFUART_MR1_RXERRCHAR;
        mr2 = 0;

        switch (termios->c_cflag & CSIZE) {
        case CS5: mr1 |= MCFUART_MR1_CS5; break;
        case CS6: mr1 |= MCFUART_MR1_CS6; break;
        case CS7: mr1 |= MCFUART_MR1_CS7; break;
        case CS8:
        default:  mr1 |= MCFUART_MR1_CS8; break;
        }

        if (termios->c_cflag & PARENB) {
                if (termios->c_cflag & CMSPAR) {
                        if (termios->c_cflag & PARODD)
                                mr1 |= MCFUART_MR1_PARITYMARK;
                        else
                                mr1 |= MCFUART_MR1_PARITYSPACE;
                } else {
                        if (termios->c_cflag & PARODD)
                                mr1 |= MCFUART_MR1_PARITYODD;
                        else
                                mr1 |= MCFUART_MR1_PARITYEVEN;
                }
        } else {
                mr1 |= MCFUART_MR1_PARITYNONE;
        }

        /*
         * FIXME: port->read_status_mask and port->ignore_status_mask
         * need to be initialized based on termios settings for
         * INPCK, IGNBRK, IGNPAR, PARMRK, BRKINT
         */

        if (termios->c_cflag & CSTOPB)
                mr2 |= MCFUART_MR2_STOP2;
        else
                mr2 |= MCFUART_MR2_STOP1;

        if (termios->c_cflag & CRTSCTS) {
                mr1 |= MCFUART_MR1_RXRTS;
                mr2 |= MCFUART_MR2_TXCTS;
        }

        uart_port_lock_irqsave(port, &flags);
        if (port->rs485.flags & SER_RS485_ENABLED) {
                dev_dbg(port->dev, "Setting UART to RS485\n");
                mr2 |= MCFUART_MR2_TXRTS;
        }

        uart_update_timeout(port, termios->c_cflag, baud);
        writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
        writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR);
        writeb(MCFUART_UCR_CMDRESETMRPTR, port->membase + MCFUART_UCR);
        writeb(mr1, port->membase + MCFUART_UMR);
        writeb(mr2, port->membase + MCFUART_UMR);
        writeb((baudclk & 0xff00) >> 8, port->membase + MCFUART_UBG1);
        writeb((baudclk & 0xff), port->membase + MCFUART_UBG2);
#if defined(CONFIG_M5272)
        writeb((baudfr & 0x0f), port->membase + MCFUART_UFPD);
#endif
        writeb(MCFUART_UCSR_RXCLKTIMER | MCFUART_UCSR_TXCLKTIMER,
                port->membase + MCFUART_UCSR);
        writeb(MCFUART_UCR_RXENABLE | MCFUART_UCR_TXENABLE,
                port->membase + MCFUART_UCR);
        uart_port_unlock_irqrestore(port, flags);
}

/****************************************************************************/

static void mcf_rx_chars(struct mcf_uart *pp)
{
        struct uart_port *port = &pp->port;
        u8 status, ch, flag;

        while ((status = readb(port->membase + MCFUART_USR)) & MCFUART_USR_RXREADY) {
                ch = readb(port->membase + MCFUART_URB);
                flag = TTY_NORMAL;
                port->icount.rx++;

                if (status & MCFUART_USR_RXERR) {
                        writeb(MCFUART_UCR_CMDRESETERR,
                                port->membase + MCFUART_UCR);

                        if (status & MCFUART_USR_RXBREAK) {
                                port->icount.brk++;
                                if (uart_handle_break(port))
                                        continue;
                        } else if (status & MCFUART_USR_RXPARITY) {
                                port->icount.parity++;
                        } else if (status & MCFUART_USR_RXOVERRUN) {
                                port->icount.overrun++;
                        } else if (status & MCFUART_USR_RXFRAMING) {
                                port->icount.frame++;
                        }

                        status &= port->read_status_mask;

                        if (status & MCFUART_USR_RXBREAK)
                                flag = TTY_BREAK;
                        else if (status & MCFUART_USR_RXPARITY)
                                flag = TTY_PARITY;
                        else if (status & MCFUART_USR_RXFRAMING)
                                flag = TTY_FRAME;
                }

                if (uart_handle_sysrq_char(port, ch))
                        continue;
                uart_insert_char(port, status, MCFUART_USR_RXOVERRUN, ch, flag);
        }

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

/****************************************************************************/

static void mcf_tx_chars(struct mcf_uart *pp)
{
        struct uart_port *port = &pp->port;
        bool pending;
        u8 ch;

        pending = uart_port_tx(port, ch,
                readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY,
                writeb(ch, port->membase + MCFUART_UTB));

        /* Disable TX to negate RTS automatically */
        if (!pending && (port->rs485.flags & SER_RS485_ENABLED))
                writeb(MCFUART_UCR_TXDISABLE, port->membase + MCFUART_UCR);
}

/****************************************************************************/

static irqreturn_t mcf_interrupt(int irq, void *data)
{
        struct uart_port *port = data;
        struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
        unsigned int isr;
        irqreturn_t ret = IRQ_NONE;

        isr = readb(port->membase + MCFUART_UISR) & pp->imr;

        uart_port_lock(port);
        if (isr & MCFUART_UIR_RXREADY) {
                mcf_rx_chars(pp);
                ret = IRQ_HANDLED;
        }
        if (isr & MCFUART_UIR_TXREADY) {
                mcf_tx_chars(pp);
                ret = IRQ_HANDLED;
        }
        uart_port_unlock(port);

        return ret;
}

/****************************************************************************/

static void mcf_config_port(struct uart_port *port, int flags)
{
        port->type = PORT_MCF;
        port->fifosize = MCFUART_TXFIFOSIZE;

        /* Clear mask, so no surprise interrupts. */
        writeb(0, port->membase + MCFUART_UIMR);

        if (request_irq(port->irq, mcf_interrupt, 0, "UART", port))
                printk(KERN_ERR "MCF: unable to attach ColdFire UART %d "
                        "interrupt vector=%d\n", port->line, port->irq);
}

/****************************************************************************/

static const char *mcf_type(struct uart_port *port)
{
        return (port->type == PORT_MCF) ? "ColdFire UART" : NULL;
}

/****************************************************************************/

static int mcf_request_port(struct uart_port *port)
{
        /* UARTs always present */
        return 0;
}

/****************************************************************************/

static void mcf_release_port(struct uart_port *port)
{
        /* Nothing to release... */
}

/****************************************************************************/

static int mcf_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_MCF))
                return -EINVAL;
        return 0;
}

/****************************************************************************/

/* Enable or disable the RS485 support */
static int mcf_config_rs485(struct uart_port *port, struct ktermios *termios,
                            struct serial_rs485 *rs485)
{
        unsigned char mr1, mr2;

        /* Get mode registers */
        mr1 = readb(port->membase + MCFUART_UMR);
        mr2 = readb(port->membase + MCFUART_UMR);
        if (rs485->flags & SER_RS485_ENABLED) {
                dev_dbg(port->dev, "Setting UART to RS485\n");
                /* Automatically negate RTS after TX completes */
                mr2 |= MCFUART_MR2_TXRTS;
        } else {
                dev_dbg(port->dev, "Setting UART to RS232\n");
                mr2 &= ~MCFUART_MR2_TXRTS;
        }
        writeb(mr1, port->membase + MCFUART_UMR);
        writeb(mr2, port->membase + MCFUART_UMR);

        return 0;
}

static const struct serial_rs485 mcf_rs485_supported = {
        .flags = SER_RS485_ENABLED | SER_RS485_RTS_AFTER_SEND,
};

/****************************************************************************/

/*
 *      Define the basic serial functions we support.
 */
static const struct uart_ops mcf_uart_ops = {
        .tx_empty       = mcf_tx_empty,
        .get_mctrl      = mcf_get_mctrl,
        .set_mctrl      = mcf_set_mctrl,
        .start_tx       = mcf_start_tx,
        .stop_tx        = mcf_stop_tx,
        .stop_rx        = mcf_stop_rx,
        .break_ctl      = mcf_break_ctl,
        .startup        = mcf_startup,
        .shutdown       = mcf_shutdown,
        .set_termios    = mcf_set_termios,
        .type           = mcf_type,
        .request_port   = mcf_request_port,
        .release_port   = mcf_release_port,
        .config_port    = mcf_config_port,
        .verify_port    = mcf_verify_port,
};

static struct mcf_uart mcf_ports[10];

#define MCF_MAXPORTS    ARRAY_SIZE(mcf_ports)

/****************************************************************************/
#if defined(CONFIG_SERIAL_MCF_CONSOLE)
/****************************************************************************/

static void mcf_console_putc(struct console *co, const char c)
{
        struct uart_port *port = &(mcf_ports + co->index)->port;
        int i;

        for (i = 0; (i < 0x10000); i++) {
                if (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY)
                        break;
        }
        writeb(c, port->membase + MCFUART_UTB);
        for (i = 0; (i < 0x10000); i++) {
                if (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY)
                        break;
        }
}

/****************************************************************************/

static void mcf_console_write(struct console *co, const char *s, unsigned int count)
{
        for (; (count); count--, s++) {
                mcf_console_putc(co, *s);
                if (*s == '\n')
                        mcf_console_putc(co, '\r');
        }
}

/****************************************************************************/

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

        if ((co->index < 0) || (co->index >= MCF_MAXPORTS))
                co->index = 0;
        port = &mcf_ports[co->index].port;
        if (port->membase == 0)
                return -ENODEV;

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

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

/****************************************************************************/

static struct uart_driver mcf_driver;

static struct console mcf_console = {
        .name           = "ttyS",
        .write          = mcf_console_write,
        .device         = uart_console_device,
        .setup          = mcf_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
        .data           = &mcf_driver,
};

static int __init mcf_console_init(void)
{
        register_console(&mcf_console);
        return 0;
}

console_initcall(mcf_console_init);

#define MCF_CONSOLE     &mcf_console

/****************************************************************************/
#else
/****************************************************************************/

#define MCF_CONSOLE     NULL

/****************************************************************************/
#endif /* CONFIG_SERIAL_MCF_CONSOLE */
/****************************************************************************/

/*
 *      Define the mcf UART driver structure.
 */
static struct uart_driver mcf_driver = {
        .owner          = THIS_MODULE,
        .driver_name    = "mcf",
        .dev_name       = "ttyS",
        .major          = TTY_MAJOR,
        .minor          = 64,
        .nr             = MCF_MAXPORTS,
        .cons           = MCF_CONSOLE,
};

/****************************************************************************/

static int mcf_probe(struct platform_device *pdev)
{
        struct mcf_platform_uart *platp = dev_get_platdata(&pdev->dev);
        struct uart_port *port;
        int i;

        for (i = 0; ((i < MCF_MAXPORTS) && (platp[i].mapbase)); i++) {
                port = &mcf_ports[i].port;

                port->line = i;
                port->type = PORT_MCF;
                port->mapbase = platp[i].mapbase;
                port->membase = (platp[i].membase) ? platp[i].membase :
                        (unsigned char __iomem *) platp[i].mapbase;
                port->dev = &pdev->dev;
                port->iotype = SERIAL_IO_MEM;
                port->irq = platp[i].irq;
                port->uartclk = MCF_BUSCLK;
                port->ops = &mcf_uart_ops;
                port->flags = UPF_BOOT_AUTOCONF;
                port->rs485_config = mcf_config_rs485;
                port->rs485_supported = mcf_rs485_supported;
                port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MCF_CONSOLE);

                uart_add_one_port(&mcf_driver, port);
        }

        return 0;
}

/****************************************************************************/

static void mcf_remove(struct platform_device *pdev)
{
        struct uart_port *port;
        int i;

        for (i = 0; (i < MCF_MAXPORTS); i++) {
                port = &mcf_ports[i].port;
                if (port)
                        uart_remove_one_port(&mcf_driver, port);
        }
}

/****************************************************************************/

static struct platform_driver mcf_platform_driver = {
        .probe          = mcf_probe,
        .remove         = mcf_remove,
        .driver         = {
                .name   = "mcfuart",
        },
};

/****************************************************************************/

static int __init mcf_init(void)
{
        int rc;

        printk("ColdFire internal UART serial driver\n");

        rc = uart_register_driver(&mcf_driver);
        if (rc)
                return rc;
        rc = platform_driver_register(&mcf_platform_driver);
        if (rc) {
                uart_unregister_driver(&mcf_driver);
                return rc;
        }
        return 0;
}

/****************************************************************************/

static void __exit mcf_exit(void)
{
        platform_driver_unregister(&mcf_platform_driver);
        uart_unregister_driver(&mcf_driver);
}

/****************************************************************************/

module_init(mcf_init);
module_exit(mcf_exit);

MODULE_AUTHOR("Greg Ungerer <gerg@uclinux.org>");
MODULE_DESCRIPTION("Freescale ColdFire UART driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:mcfuart");

/****************************************************************************/