[J-u-boot.git] / drivers / serial / serial.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2004
 * Wolfgang Denk, DENX Software Engineering, [email protected].
 */

#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>
#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 (getc() == '\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.
 */
void 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);
}

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
Commit	Line	Data
83d290c5	1	// SPDX-License-Identifier: GPL-2.0+
281e00a3 WD	2	/*
	3	* (C) Copyright 2004
	4	* Wolfgang Denk, DENX Software Engineering, [email protected].
281e00a3 WD	5	*/
	6
	7	#include <common.h>
f3998fdc	8	#include <env_internal.h>
db41d65a	9	#include <hang.h>
281e00a3	10	#include <serial.h>
52cb4d4f	11	#include <stdio_dev.h>
7b826c2f MF	12	#include <post.h>
7b826c2f MF	13	#include <linux/compiler.h>
6d93e258	14	#include <errno.h>
c05ed00a	15	#include <linux/delay.h>
281e00a3	16
d87080b7 WD	17	DECLARE_GLOBAL_DATA_PTR;
d87080b7 WD	18
a6e6f7f4 GF	19	static struct serial_device *serial_devices;
a6e6f7f4 GF	20	static struct serial_device *serial_current;
32057717 JH	21	/*
	22	* Table with supported baudrates (defined in config_xyz.h)
	23	*/
	24	static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;
281e00a3	25
9cd2b9e4 MV	26	/**
	27	* serial_null() - Void registration routine of a serial driver
	28	*
	29	* This routine implements a void registration routine of a serial
	30	* driver. The registration routine of a particular driver is aliased
	31	* to this empty function in case the driver is not compiled into
	32	* U-Boot.
	33	*/
2a333aeb MV	34	static void serial_null(void)
	35	{
	36	}
	37
32057717 JH	38	/**
	39	* on_baudrate() - Update the actual baudrate when the env var changes
	40	*
938b05a5 HS	41	* @name: changed environment variable
	42	* @value: new value of the environment variable
	43	* @op: operation (create, overwrite, or delete)
	44	* @flags: attributes of environment variable change,
	45	* see flags H_* in include/search.h
	46	*
32057717	47	* This will check for a valid baudrate and only apply it if valid.
938b05a5 HS	48	*
938b05a5 HS	49	* Return: 0 on success, 1 on error
32057717 JH	50	*/
	51	static int on_baudrate(const char name, const char value, enum env_op op,
	52	int flags)
	53	{
	54	int i;
	55	int baudrate;
	56
	57	switch (op) {
	58	case env_op_create:
	59	case env_op_overwrite:
	60	/*
	61	* Switch to new baudrate if new baudrate is supported
	62	*/
	63	baudrate = simple_strtoul(value, NULL, 10);
	64
	65	/* Not actually changing */
	66	if (gd->baudrate == baudrate)
	67	return 0;
	68
9935175f	69	for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
32057717 JH	70	if (baudrate == baudrate_table[i])
	71	break;
	72	}
9935175f	73	if (i == ARRAY_SIZE(baudrate_table)) {
32057717 JH	74	if ((flags & H_FORCE) == 0)
	75	printf("## Baudrate %d bps not supported\n",
	76	baudrate);
	77	return 1;
	78	}
	79	if ((flags & H_INTERACTIVE) != 0) {
	80	printf("## Switch baudrate to %d"
	81	" bps and press ENTER ...\n", baudrate);
	82	udelay(50000);
	83	}
	84
	85	gd->baudrate = baudrate;
32057717 JH	86
	87	serial_setbrg();
	88
	89	udelay(50000);
	90
	91	if ((flags & H_INTERACTIVE) != 0)
	92	while (1) {
	93	if (getc() == '\r')
	94	break;
	95	}
	96
	97	return 0;
	98	case env_op_delete:
	99	printf("## Baudrate may not be deleted\n");
	100	return 1;
	101	default:
	102	return 0;
	103	}
	104	}
	105	U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
	106
9cd2b9e4 MV	107	/**
	108	* serial_initfunc() - Forward declare of driver registration routine
	109	* @name: Name of the real driver registration routine.
	110	*
	111	* This macro expands onto forward declaration of a driver registration
	112	* routine, which is then used below in serial_initialize() function.
	113	* The declaration is made weak and aliases to serial_null() so in case
	114	* the driver is not compiled in, the function is still declared and can
	115	* be used, but aliases to serial_null() and thus is optimized away.
	116	*/
2a333aeb MV	117	#define serial_initfunc(name) \
	118	void name(void) \
	119	__attribute__((weak, alias("serial_null")));
	120
94a255df	121	serial_initfunc(atmel_serial_initialize);
94a255df	122	serial_initfunc(mcf_serial_initialize);
94a255df	123	serial_initfunc(mpc85xx_serial_initialize);
a943472c	124	serial_initfunc(mxc_serial_initialize);
94a255df	125	serial_initfunc(ns16550_serial_initialize);
39f61477	126	serial_initfunc(pl01x_serial_initialize);
94a255df	127	serial_initfunc(pxa_serial_initialize);
8bdd7efa	128	serial_initfunc(sh_serial_initialize);
44fa676e	129	serial_initfunc(mtk_serial_initialize);
f0eb1f61	130
9cd2b9e4 MV	131	/**
	132	* serial_register() - Register serial driver with serial driver core
	133	* @dev: Pointer to the serial driver structure
	134	*
	135	* This function registers the serial driver supplied via @dev with
	136	* serial driver core, thus making U-Boot aware of it and making it
	137	* available for U-Boot to use. On platforms that still require manual
	138	* relocation of constant variables, relocation of the supplied structure
	139	* is performed.
	140	*/
c52b4f79	141	void serial_register(struct serial_device *dev)
281e00a3	142	{
2e5167cc	143	#ifdef CONFIG_NEEDS_MANUAL_RELOC
f2760c4a MV	144	if (dev->start)
	145	dev->start += gd->reloc_off;
	146	if (dev->stop)
	147	dev->stop += gd->reloc_off;
	148	if (dev->setbrg)
	149	dev->setbrg += gd->reloc_off;
	150	if (dev->getc)
	151	dev->getc += gd->reloc_off;
	152	if (dev->tstc)
	153	dev->tstc += gd->reloc_off;
	154	if (dev->putc)
	155	dev->putc += gd->reloc_off;
	156	if (dev->puts)
	157	dev->puts += gd->reloc_off;
521af04d	158	#endif
281e00a3 WD	159
	160	dev->next = serial_devices;
	161	serial_devices = dev;
281e00a3 WD	162	}
281e00a3 WD	163
9cd2b9e4 MV	164	/**
	165	* serial_initialize() - Register all compiled-in serial port drivers
	166	*
	167	* This function registers all serial port drivers that are compiled
	168	* into the U-Boot binary with the serial core, thus making them
	169	* available to U-Boot to use. Lastly, this function assigns a default
	170	* serial port to the serial core. That serial port is then used as a
	171	* default output.
	172	*/
a6e6f7f4	173	void serial_initialize(void)
281e00a3	174	{
94a255df	175	atmel_serial_initialize();
94a255df	176	mcf_serial_initialize();
94a255df	177	mpc85xx_serial_initialize();
a943472c	178	mxc_serial_initialize();
94a255df	179	ns16550_serial_initialize();
39f61477	180	pl01x_serial_initialize();
94a255df	181	pxa_serial_initialize();
8bdd7efa	182	sh_serial_initialize();
44fa676e	183	mtk_serial_initialize();
7b953c51	184
a6e6f7f4	185	serial_assign(default_serial_console()->name);
281e00a3 WD	186	}
281e00a3 WD	187
654f8d0f	188	static int serial_stub_start(struct stdio_dev *sdev)
709ea543 SG	189	{
	190	struct serial_device *dev = sdev->priv;
	191
	192	return dev->start();
	193	}
	194
654f8d0f	195	static int serial_stub_stop(struct stdio_dev *sdev)
709ea543 SG	196	{
	197	struct serial_device *dev = sdev->priv;
	198
	199	return dev->stop();
	200	}
	201
654f8d0f	202	static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
709ea543 SG	203	{
	204	struct serial_device *dev = sdev->priv;
	205
	206	dev->putc(ch);
	207	}
	208
654f8d0f	209	static void serial_stub_puts(struct stdio_dev sdev, const char str)
709ea543 SG	210	{
	211	struct serial_device *dev = sdev->priv;
	212
	213	dev->puts(str);
	214	}
	215
49ddcf3e	216	static int serial_stub_getc(struct stdio_dev *sdev)
709ea543 SG	217	{
	218	struct serial_device *dev = sdev->priv;
	219
	220	return dev->getc();
	221	}
	222
49ddcf3e	223	static int serial_stub_tstc(struct stdio_dev *sdev)
709ea543 SG	224	{
	225	struct serial_device *dev = sdev->priv;
	226
	227	return dev->tstc();
	228	}
	229
9cd2b9e4 MV	230	/**
	231	* serial_stdio_init() - Register serial ports with STDIO core
	232	*
	233	* This function generates a proxy driver for each serial port driver.
	234	* These proxy drivers then register with the STDIO core, making the
	235	* serial drivers available as STDIO devices.
	236	*/
a6e6f7f4	237	void serial_stdio_init(void)
281e00a3	238	{
52cb4d4f	239	struct stdio_dev dev;
281e00a3 WD	240	struct serial_device *s = serial_devices;
281e00a3 WD	241
2ee66533	242	while (s) {
a6e6f7f4	243	memset(&dev, 0, sizeof(dev));
281e00a3	244
a6e6f7f4	245	strcpy(dev.name, s->name);
281e00a3 WD	246	dev.flags = DEV_FLAGS_OUTPUT \| DEV_FLAGS_INPUT;
281e00a3 WD	247
709ea543 SG	248	dev.start = serial_stub_start;
	249	dev.stop = serial_stub_stop;
	250	dev.putc = serial_stub_putc;
	251	dev.puts = serial_stub_puts;
	252	dev.getc = serial_stub_getc;
	253	dev.tstc = serial_stub_tstc;
addf9513	254	dev.priv = s;
281e00a3	255
a6e6f7f4	256	stdio_register(&dev);
281e00a3 WD	257
	258	s = s->next;
	259	}
	260	}
	261
9cd2b9e4 MV	262	/**
	263	* serial_assign() - Select the serial output device by name
	264	* @name: Name of the serial driver to be used as default output
	265	*
	266	* This function configures the serial output multiplexing by
	267	* selecting which serial device will be used as default. In case
	268	* the STDIO "serial" device is selected as stdin/stdout/stderr,
	269	* the serial device previously configured by this function will be
	270	* used for the particular operation.
	271	*
	272	* Returns 0 on success, negative on error.
	273	*/
7813ca9b	274	int serial_assign(const char *name)
281e00a3 WD	275	{
	276	struct serial_device *s;
	277
2ee66533	278	for (s = serial_devices; s; s = s->next) {
6d93e258 MV	279	if (strcmp(s->name, name))
	280	continue;
	281	serial_current = s;
	282	return 0;
281e00a3 WD	283	}
281e00a3 WD	284
6d93e258	285	return -EINVAL;
281e00a3 WD	286	}
281e00a3 WD	287
9cd2b9e4 MV	288	/**
	289	* serial_reinit_all() - Reinitialize all compiled-in serial ports
	290	*
	291	* This function reinitializes all serial ports that are compiled
	292	* into U-Boot by calling their serial_start() functions.
	293	*/
a6e6f7f4	294	void serial_reinit_all(void)
281e00a3 WD	295	{
	296	struct serial_device *s;
	297
a6e6f7f4	298	for (s = serial_devices; s; s = s->next)
89143fb3	299	s->start();
281e00a3 WD	300	}
281e00a3 WD	301
9cd2b9e4 MV	302	/**
	303	* get_current() - Return pointer to currently selected serial port
	304	*
	305	* This function returns a pointer to currently selected serial port.
	306	* The currently selected serial port is altered by serial_assign()
	307	* function.
	308	*
	309	* In case this function is called before relocation or before any serial
	310	* port is configured, this function calls default_serial_console() to
	311	* determine the serial port. Otherwise, the configured serial port is
	312	* returned.
	313	*
	314	* Returns pointer to the currently selected serial port on success,
	315	* NULL on error.
	316	*/
857c283e	317	static struct serial_device *get_current(void)
281e00a3	318	{
857c283e	319	struct serial_device *dev;
2ee66533	320
dee19416	321	if (!(gd->flags & GD_FLG_RELOC))
857c283e	322	dev = default_serial_console();
dee19416 MV	323	else if (!serial_current)
	324	dev = default_serial_console();
	325	else
	326	dev = serial_current;
857c283e	327
dee19416 MV	328	/* We must have a console device */
dee19416 MV	329	if (!dev) {
f1f1e9cb	330	#ifdef CONFIG_SPL_BUILD
dee19416 MV	331	puts("Cannot find console\n");
dee19416 MV	332	hang();
f1f1e9cb	333	#else
dee19416	334	panic("Cannot find console\n");
f1f1e9cb	335	#endif
dee19416 MV	336	}
dee19416 MV	337
857c283e SG	338	return dev;
857c283e SG	339	}
281e00a3	340
9cd2b9e4 MV	341	/**
	342	* serial_init() - Initialize currently selected serial port
	343	*
	344	* This function initializes the currently selected serial port. This
	345	* usually involves setting up the registers of that particular port,
	346	* enabling clock and such. This function uses the get_current() call
	347	* to determine which port is selected.
	348	*
	349	* Returns 0 on success, negative on error.
	350	*/
857c283e SG	351	int serial_init(void)
857c283e SG	352	{
093f79ab	353	gd->flags \|= GD_FLG_SERIAL_READY;
89143fb3	354	return get_current()->start();
281e00a3 WD	355	}
281e00a3 WD	356
9cd2b9e4 MV	357	/**
	358	* serial_setbrg() - Configure baud-rate of currently selected serial port
	359	*
	360	* This function configures the baud-rate of the currently selected
	361	* serial port. The baud-rate is retrieved from global data within
	362	* the serial port driver. This function uses the get_current() call
	363	* to determine which port is selected.
	364	*
	365	* Returns 0 on success, negative on error.
	366	*/
a6e6f7f4	367	void serial_setbrg(void)
281e00a3	368	{
857c283e	369	get_current()->setbrg();
281e00a3 WD	370	}
281e00a3 WD	371
9cd2b9e4 MV	372	/**
	373	* serial_getc() - Read character from currently selected serial port
	374	*
	375	* This function retrieves a character from currently selected serial
	376	* port. In case there is no character waiting on the serial port,
	377	* this function will block and wait for the character to appear. This
	378	* function uses the get_current() call to determine which port is
	379	* selected.
	380	*
	381	* Returns the character on success, negative on error.
	382	*/
a6e6f7f4	383	int serial_getc(void)
281e00a3	384	{
857c283e	385	return get_current()->getc();
281e00a3 WD	386	}
281e00a3 WD	387
9cd2b9e4 MV	388	/**
	389	* serial_tstc() - Test if data is available on currently selected serial port
	390	*
	391	* This function tests if one or more characters are available on
	392	* currently selected serial port. This function never blocks. This
	393	* function uses the get_current() call to determine which port is
	394	* selected.
	395	*
	396	* Returns positive if character is available, zero otherwise.
	397	*/
a6e6f7f4	398	int serial_tstc(void)
281e00a3	399	{
857c283e	400	return get_current()->tstc();
281e00a3 WD	401	}
281e00a3 WD	402
9cd2b9e4 MV	403	/**
	404	* serial_putc() - Output character via currently selected serial port
	405	* @c: Single character to be output from the serial port.
	406	*
	407	* This function outputs a character via currently selected serial
	408	* port. This character is passed to the serial port driver responsible
	409	* for controlling the hardware. The hardware may still be in process
	410	* of transmitting another character, therefore this function may block
	411	* for a short amount of time. This function uses the get_current()
	412	* call to determine which port is selected.
	413	*/
a6e6f7f4	414	void serial_putc(const char c)
281e00a3	415	{
857c283e	416	get_current()->putc(c);
281e00a3 WD	417	}
281e00a3 WD	418
9cd2b9e4 MV	419	/**
	420	* serial_puts() - Output string via currently selected serial port
	421	* @s: Zero-terminated string to be output from the serial port.
	422	*
	423	* This function outputs a zero-terminated string via currently
	424	* selected serial port. This function behaves as an accelerator
	425	* in case the hardware can queue multiple characters for transfer.
	426	* The whole string that is to be output is available to the function
	427	* implementing the hardware manipulation. Transmitting the whole
	428	* string may take some time, thus this function may block for some
	429	* amount of time. This function uses the get_current() call to
	430	* determine which port is selected.
	431	*/
a6e6f7f4	432	void serial_puts(const char *s)
281e00a3	433	{
857c283e	434	get_current()->puts(s);
281e00a3	435	}
7b826c2f	436
9cd2b9e4 MV	437	/**
	438	* default_serial_puts() - Output string by calling serial_putc() in loop
	439	* @s: Zero-terminated string to be output from the serial port.
	440	*
	441	* This function outputs a zero-terminated string by calling serial_putc()
	442	* in a loop. Most drivers do not support queueing more than one byte for
	443	* transfer, thus this function precisely implements their serial_puts().
	444	*
	445	* To optimize the number of get_current() calls, this function only
	446	* calls get_current() once and then directly accesses the putc() call
	447	* of the &struct serial_device .
	448	*/
bfb7d7a3 MV	449	void default_serial_puts(const char *s)
	450	{
	451	struct serial_device *dev = get_current();
	452	while (*s)
	453	dev->putc(*s++);
	454	}
	455
7b826c2f MF	456	#if CONFIG_POST & CONFIG_SYS_POST_UART
	457	static const int bauds[] = CONFIG_SYS_BAUDRATE_TABLE;
	458
9cd2b9e4 MV	459	/**
	460	* uart_post_test() - Test the currently selected serial port using POST
	461	* @flags: POST framework flags
	462	*
	463	* Do a loopback test of the currently selected serial port. This
	464	* function is only useful in the context of the POST testing framwork.
1b25e586	465	* The serial port is first configured into loopback mode and then
9cd2b9e4 MV	466	* characters are sent through it.
	467	*
	468	* Returns 0 on success, value otherwise.
	469	*/
7b826c2f MF	470	/* Mark weak until post/cpu/.../uart.c migrate over */
	471	__weak
	472	int uart_post_test(int flags)
	473	{
	474	unsigned char c;
	475	int ret, saved_baud, b;
	476	struct serial_device saved_dev, s;
7b826c2f MF	477
	478	/* Save current serial state */
	479	ret = 0;
	480	saved_dev = serial_current;
8e261575	481	saved_baud = gd->baudrate;
7b826c2f MF	482
	483	for (s = serial_devices; s; s = s->next) {
	484	/* If this driver doesn't support loop back, skip it */
	485	if (!s->loop)
	486	continue;
	487
	488	/* Test the next device */
	489	serial_current = s;
	490
	491	ret = serial_init();
	492	if (ret)
	493	goto done;
	494
	495	/* Consume anything that happens to be queued */
	496	while (serial_tstc())
	497	serial_getc();
	498
	499	/* Enable loop back */
	500	s->loop(1);
	501
	502	/* Test every available baud rate */
	503	for (b = 0; b < ARRAY_SIZE(bauds); ++b) {
8e261575	504	gd->baudrate = bauds[b];
7b826c2f MF	505	serial_setbrg();
	506
	507	/*
	508	* Stick to printable chars to avoid issues:
	509	* - terminal corruption
	510	* - serial program reacting to sequences and sending
	511	* back random extra data
	512	* - most serial drivers add in extra chars (like \r\n)
	513	*/
	514	for (c = 0x20; c < 0x7f; ++c) {
	515	/* Send it out */
	516	serial_putc(c);
	517
	518	/* Make sure it's the same one */
	519	ret = (c != serial_getc());
	520	if (ret) {
	521	s->loop(0);
	522	goto done;
	523	}
	524
	525	/* Clean up the output in case it was sent */
	526	serial_putc('\b');
	527	ret = ('\b' != serial_getc());
	528	if (ret) {
	529	s->loop(0);
	530	goto done;
	531	}
	532	}
	533	}
	534
	535	/* Disable loop back */
	536	s->loop(0);
	537
89143fb3 MV	538	/* XXX: There is no serial_stop() !? */
	539	if (s->stop)
	540	s->stop();
7b826c2f MF	541	}
	542
	543	done:
	544	/* Restore previous serial state */
	545	serial_current = saved_dev;
8e261575	546	gd->baudrate = saved_baud;
7b826c2f MF	547	serial_reinit_all();
	548	serial_setbrg();
	549
	550	return ret;
	551	}
	552	#endif