// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2004
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 */

#include <common.h>
#include <env_internal.h>
#include <hang.h>
#include <serial.h>
#include <stdio_dev.h>
#include <post.h>
#include <asm/global_data.h>
#include <linux/compiler.h>
#include <errno.h>
#include <linux/delay.h>

DECLARE_GLOBAL_DATA_PTR;

static struct serial_device *serial_devices;
static struct serial_device *serial_current;
/*
 * Table with supported baudrates (defined in config_xyz.h)
 */
static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;

/**
 * serial_null() - Void registration routine of a serial driver
 *
 * This routine implements a void registration routine of a serial
 * driver. The registration routine of a particular driver is aliased
 * to this empty function in case the driver is not compiled into
 * U-Boot.
 */
static void serial_null(void)
{
}

/**
 * on_baudrate() - Update the actual baudrate when the env var changes
 *
 * @name:       changed environment variable
 * @value:      new value of the environment variable
 * @op:         operation (create, overwrite, or delete)
 * @flags:      attributes of environment variable change,
 *              see flags H_* in include/search.h
 *
 * This will check for a valid baudrate and only apply it if valid.
 *
 * Return:      0 on success, 1 on error
 */
static int on_baudrate(const char *name, const char *value, enum env_op op,
        int flags)
{
        int i;
        int baudrate;

        switch (op) {
        case env_op_create:
        case env_op_overwrite:
                /*
                 * Switch to new baudrate if new baudrate is supported
                 */
                baudrate = simple_strtoul(value, NULL, 10);

                /* Not actually changing */
                if (gd->baudrate == baudrate)
                        return 0;

                for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
                        if (baudrate == baudrate_table[i])
                                break;
                }
                if (i == ARRAY_SIZE(baudrate_table)) {
                        if ((flags & H_FORCE) == 0)
                                printf("## Baudrate %d bps not supported\n",
                                        baudrate);
                        return 1;
                }
                if ((flags & H_INTERACTIVE) != 0) {
                        printf("## Switch baudrate to %d"
                                " bps and press ENTER ...\n", baudrate);
                        udelay(50000);
                }

                gd->baudrate = baudrate;

                serial_setbrg();

                udelay(50000);

                if ((flags & H_INTERACTIVE) != 0)
                        while (1) {
                                if (getchar() == '\r')
                                        break;
                        }

                return 0;
        case env_op_delete:
                printf("## Baudrate may not be deleted\n");
                return 1;
        default:
                return 0;
        }
}
U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);

/**
 * serial_initfunc() - Forward declare of driver registration routine
 * @name:       Name of the real driver registration routine.
 *
 * This macro expands onto forward declaration of a driver registration
 * routine, which is then used below in serial_initialize() function.
 * The declaration is made weak and aliases to serial_null() so in case
 * the driver is not compiled in, the function is still declared and can
 * be used, but aliases to serial_null() and thus is optimized away.
 */
#define serial_initfunc(name)                                   \
        void name(void)                                         \
                __attribute__((weak, alias("serial_null")));

serial_initfunc(atmel_serial_initialize);
serial_initfunc(mcf_serial_initialize);
serial_initfunc(mpc85xx_serial_initialize);
serial_initfunc(mxc_serial_initialize);
serial_initfunc(ns16550_serial_initialize);
serial_initfunc(pl01x_serial_initialize);
serial_initfunc(pxa_serial_initialize);
serial_initfunc(sh_serial_initialize);
serial_initfunc(mtk_serial_initialize);

/**
 * serial_register() - Register serial driver with serial driver core
 * @dev:        Pointer to the serial driver structure
 *
 * This function registers the serial driver supplied via @dev with
 * serial driver core, thus making U-Boot aware of it and making it
 * available for U-Boot to use. On platforms that still require manual
 * relocation of constant variables, relocation of the supplied structure
 * is performed.
 */
void serial_register(struct serial_device *dev)
{
#ifdef CONFIG_NEEDS_MANUAL_RELOC
        if (dev->start)
                dev->start += gd->reloc_off;
        if (dev->stop)
                dev->stop += gd->reloc_off;
        if (dev->setbrg)
                dev->setbrg += gd->reloc_off;
        if (dev->getc)
                dev->getc += gd->reloc_off;
        if (dev->tstc)
                dev->tstc += gd->reloc_off;
        if (dev->putc)
                dev->putc += gd->reloc_off;
        if (dev->puts)
                dev->puts += gd->reloc_off;
#endif

        dev->next = serial_devices;
        serial_devices = dev;
}

/**
 * serial_initialize() - Register all compiled-in serial port drivers
 *
 * This function registers all serial port drivers that are compiled
 * into the U-Boot binary with the serial core, thus making them
 * available to U-Boot to use. Lastly, this function assigns a default
 * serial port to the serial core. That serial port is then used as a
 * default output.
 */
int serial_initialize(void)
{
        atmel_serial_initialize();
        mcf_serial_initialize();
        mpc85xx_serial_initialize();
        mxc_serial_initialize();
        ns16550_serial_initialize();
        pl01x_serial_initialize();
        pxa_serial_initialize();
        sh_serial_initialize();
        mtk_serial_initialize();

        serial_assign(default_serial_console()->name);

        return 0;
}

static int serial_stub_start(struct stdio_dev *sdev)
{
        struct serial_device *dev = sdev->priv;

        return dev->start();
}

static int serial_stub_stop(struct stdio_dev *sdev)
{
        struct serial_device *dev = sdev->priv;

        return dev->stop();
}

static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
{
        struct serial_device *dev = sdev->priv;

        dev->putc(ch);
}

static void serial_stub_puts(struct stdio_dev *sdev, const char *str)
{
        struct serial_device *dev = sdev->priv;

        dev->puts(str);
}

static int serial_stub_getc(struct stdio_dev *sdev)
{
        struct serial_device *dev = sdev->priv;

        return dev->getc();
}

static int serial_stub_tstc(struct stdio_dev *sdev)
{
        struct serial_device *dev = sdev->priv;

        return dev->tstc();
}

/**
 * serial_stdio_init() - Register serial ports with STDIO core
 *
 * This function generates a proxy driver for each serial port driver.
 * These proxy drivers then register with the STDIO core, making the
 * serial drivers available as STDIO devices.
 */
void serial_stdio_init(void)
{
        struct stdio_dev dev;
        struct serial_device *s = serial_devices;

        while (s) {
                memset(&dev, 0, sizeof(dev));

                strcpy(dev.name, s->name);
                dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;

                dev.start = serial_stub_start;
                dev.stop = serial_stub_stop;
                dev.putc = serial_stub_putc;
                dev.puts = serial_stub_puts;
                dev.getc = serial_stub_getc;
                dev.tstc = serial_stub_tstc;
                dev.priv = s;

                stdio_register(&dev);

                s = s->next;
        }
}

/**
 * serial_assign() - Select the serial output device by name
 * @name:       Name of the serial driver to be used as default output
 *
 * This function configures the serial output multiplexing by
 * selecting which serial device will be used as default. In case
 * the STDIO "serial" device is selected as stdin/stdout/stderr,
 * the serial device previously configured by this function will be
 * used for the particular operation.
 *
 * Returns 0 on success, negative on error.
 */
int serial_assign(const char *name)
{
        struct serial_device *s;

        for (s = serial_devices; s; s = s->next) {
                if (strcmp(s->name, name))
                        continue;
                serial_current = s;
                return 0;
        }

        return -EINVAL;
}

/**
 * serial_reinit_all() - Reinitialize all compiled-in serial ports
 *
 * This function reinitializes all serial ports that are compiled
 * into U-Boot by calling their serial_start() functions.
 */
void serial_reinit_all(void)
{
        struct serial_device *s;

        for (s = serial_devices; s; s = s->next)
                s->start();
}

/**
 * get_current() - Return pointer to currently selected serial port
 *
 * This function returns a pointer to currently selected serial port.
 * The currently selected serial port is altered by serial_assign()
 * function.
 *
 * In case this function is called before relocation or before any serial
 * port is configured, this function calls default_serial_console() to
 * determine the serial port. Otherwise, the configured serial port is
 * returned.
 *
 * Returns pointer to the currently selected serial port on success,
 * NULL on error.
 */
static struct serial_device *get_current(void)
{
        struct serial_device *dev;

        if (!(gd->flags & GD_FLG_RELOC))
                dev = default_serial_console();
        else if (!serial_current)
                dev = default_serial_console();
        else
                dev = serial_current;

        /* We must have a console device */
        if (!dev) {
#ifdef CONFIG_SPL_BUILD
                puts("Cannot find console\n");
                hang();
#else
                panic("Cannot find console\n");
#endif
        }

        return dev;
}

/**
 * serial_init() - Initialize currently selected serial port
 *
 * This function initializes the currently selected serial port. This
 * usually involves setting up the registers of that particular port,
 * enabling clock and such. This function uses the get_current() call
 * to determine which port is selected.
 *
 * Returns 0 on success, negative on error.
 */
int serial_init(void)
{
        gd->flags |= GD_FLG_SERIAL_READY;
        return get_current()->start();
}

/**
 * serial_setbrg() - Configure baud-rate of currently selected serial port
 *
 * This function configures the baud-rate of the currently selected
 * serial port. The baud-rate is retrieved from global data within
 * the serial port driver. This function uses the get_current() call
 * to determine which port is selected.
 *
 * Returns 0 on success, negative on error.
 */
void serial_setbrg(void)
{
        get_current()->setbrg();
}

/**
 * serial_getc() - Read character from currently selected serial port
 *
 * This function retrieves a character from currently selected serial
 * port. In case there is no character waiting on the serial port,
 * this function will block and wait for the character to appear. This
 * function uses the get_current() call to determine which port is
 * selected.
 *
 * Returns the character on success, negative on error.
 */
int serial_getc(void)
{
        return get_current()->getc();
}

/**
 * serial_tstc() - Test if data is available on currently selected serial port
 *
 * This function tests if one or more characters are available on
 * currently selected serial port. This function never blocks. This
 * function uses the get_current() call to determine which port is
 * selected.
 *
 * Returns positive if character is available, zero otherwise.
 */
int serial_tstc(void)
{
        return get_current()->tstc();
}

/**
 * serial_putc() - Output character via currently selected serial port
 * @c:  Single character to be output from the serial port.
 *
 * This function outputs a character via currently selected serial
 * port. This character is passed to the serial port driver responsible
 * for controlling the hardware. The hardware may still be in process
 * of transmitting another character, therefore this function may block
 * for a short amount of time. This function uses the get_current()
 * call to determine which port is selected.
 */
void serial_putc(const char c)
{
        get_current()->putc(c);
}

/**
 * serial_puts() - Output string via currently selected serial port
 * @s:  Zero-terminated string to be output from the serial port.
 *
 * This function outputs a zero-terminated string via currently
 * selected serial port. This function behaves as an accelerator
 * in case the hardware can queue multiple characters for transfer.
 * The whole string that is to be output is available to the function
 * implementing the hardware manipulation. Transmitting the whole
 * string may take some time, thus this function may block for some
 * amount of time. This function uses the get_current() call to
 * determine which port is selected.
 */
void serial_puts(const char *s)
{
        get_current()->puts(s);
}

/**
 * default_serial_puts() - Output string by calling serial_putc() in loop
 * @s:  Zero-terminated string to be output from the serial port.
 *
 * This function outputs a zero-terminated string by calling serial_putc()
 * in a loop. Most drivers do not support queueing more than one byte for
 * transfer, thus this function precisely implements their serial_puts().
 *
 * To optimize the number of get_current() calls, this function only
 * calls get_current() once and then directly accesses the putc() call
 * of the &struct serial_device .
 */
void default_serial_puts(const char *s)
{
        struct serial_device *dev = get_current();
        while (*s)
                dev->putc(*s++);
}

#if CONFIG_POST & CONFIG_SYS_POST_UART
static const int bauds[] = CONFIG_SYS_BAUDRATE_TABLE;

/**
 * uart_post_test() - Test the currently selected serial port using POST
 * @flags:      POST framework flags
 *
 * Do a loopback test of the currently selected serial port. This
 * function is only useful in the context of the POST testing framwork.
 * The serial port is first configured into loopback mode and then
 * characters are sent through it.
 *
 * Returns 0 on success, value otherwise.
 */
/* Mark weak until post/cpu/.../uart.c migrate over */
__weak
int uart_post_test(int flags)
{
        unsigned char c;
        int ret, saved_baud, b;
        struct serial_device *saved_dev, *s;

        /* Save current serial state */
        ret = 0;
        saved_dev = serial_current;
        saved_baud = gd->baudrate;

        for (s = serial_devices; s; s = s->next) {
                /* If this driver doesn't support loop back, skip it */
                if (!s->loop)
                        continue;

                /* Test the next device */
                serial_current = s;

                ret = serial_init();
                if (ret)
                        goto done;

                /* Consume anything that happens to be queued */
                while (serial_tstc())
                        serial_getc();

                /* Enable loop back */
                s->loop(1);

                /* Test every available baud rate */
                for (b = 0; b < ARRAY_SIZE(bauds); ++b) {
                        gd->baudrate = bauds[b];
                        serial_setbrg();

                        /*
                         * Stick to printable chars to avoid issues:
                         *  - terminal corruption
                         *  - serial program reacting to sequences and sending
                         *    back random extra data
                         *  - most serial drivers add in extra chars (like \r\n)
                         */
                        for (c = 0x20; c < 0x7f; ++c) {
                                /* Send it out */
                                serial_putc(c);

                                /* Make sure it's the same one */
                                ret = (c != serial_getc());
                                if (ret) {
                                        s->loop(0);
                                        goto done;
                                }

                                /* Clean up the output in case it was sent */
                                serial_putc('\b');
                                ret = ('\b' != serial_getc());
                                if (ret) {
                                        s->loop(0);
                                        goto done;
                                }
                        }
                }

                /* Disable loop back */
                s->loop(0);

                /* XXX: There is no serial_stop() !? */
                if (s->stop)
                        s->stop();
        }

 done:
        /* Restore previous serial state */
        serial_current = saved_dev;
        gd->baudrate = saved_baud;
        serial_reinit_all();
        serial_setbrg();

        return ret;
}
#endif