// 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 <linux/compiler.h>

  #include <errno.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
  ",
  					baudrate);
  			return 1;
  		}
  		if ((flags & H_INTERACTIVE) != 0) {
  			printf("## Switch baudrate to %d"
  				" bps and press ENTER ...
  ", baudrate);
  			udelay(50000);
  		}
  
  		gd->baudrate = baudrate;

  
  		serial_setbrg();
  
  		udelay(50000);
  
  		if ((flags & H_INTERACTIVE) != 0)
  			while (1) {
  				if (getc() == '\r')
  					break;
  			}
  
  		return 0;
  	case env_op_delete:
  		printf("## Baudrate may not be deleted
  ");
  		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(xen_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_initfunc(xen_debug_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.
   */

  void serial_initialize(void)

  {

  	atmel_serial_initialize();

  	mcf_serial_initialize();

  	mpc85xx_serial_initialize();

  	mxc_serial_initialize();

  	xen_serial_initialize();

  	ns16550_serial_initialize();

  	pl01x_serial_initialize();

  	pxa_serial_initialize();

  	sh_serial_initialize();

  	mtk_serial_initialize();

  	xen_debug_serial_initialize();

  	serial_assign(default_serial_console()->name);

  }

  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
  ");
  		hang();

  #else

  		panic("Cannot find console
  ");

  #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
  )
  			 */
  			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