[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 <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
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	12	#include <post.h>
401d1c4f	13	#include <asm/global_data.h>
7b826c2f	14	#include <linux/compiler.h>
6d93e258	15	#include <errno.h>
c05ed00a	16	#include <linux/delay.h>
281e00a3	17
d87080b7 WD	18	DECLARE_GLOBAL_DATA_PTR;
d87080b7 WD	19
a6e6f7f4 GF	20	static struct serial_device *serial_devices;
a6e6f7f4 GF	21	static struct serial_device *serial_current;
32057717 JH	22	/*
	23	* Table with supported baudrates (defined in config_xyz.h)
	24	*/
	25	static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;
281e00a3	26
9cd2b9e4 MV	27	/**
	28	* serial_null() - Void registration routine of a serial driver
	29	*
	30	* This routine implements a void registration routine of a serial
	31	* driver. The registration routine of a particular driver is aliased
	32	* to this empty function in case the driver is not compiled into
	33	* U-Boot.
	34	*/
2a333aeb MV	35	static void serial_null(void)
	36	{
	37	}
	38
32057717 JH	39	/**
	40	* on_baudrate() - Update the actual baudrate when the env var changes
	41	*
938b05a5 HS	42	* @name: changed environment variable
	43	* @value: new value of the environment variable
	44	* @op: operation (create, overwrite, or delete)
	45	* @flags: attributes of environment variable change,
	46	* see flags H_* in include/search.h
	47	*
32057717	48	* This will check for a valid baudrate and only apply it if valid.
938b05a5 HS	49	*
938b05a5 HS	50	* Return: 0 on success, 1 on error
32057717 JH	51	*/
	52	static int on_baudrate(const char name, const char value, enum env_op op,
	53	int flags)
	54	{
	55	int i;
	56	int baudrate;
	57
	58	switch (op) {
	59	case env_op_create:
	60	case env_op_overwrite:
	61	/*
	62	* Switch to new baudrate if new baudrate is supported
	63	*/
	64	baudrate = simple_strtoul(value, NULL, 10);
	65
	66	/* Not actually changing */
	67	if (gd->baudrate == baudrate)
	68	return 0;
	69
9935175f	70	for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
32057717 JH	71	if (baudrate == baudrate_table[i])
	72	break;
	73	}
9935175f	74	if (i == ARRAY_SIZE(baudrate_table)) {
32057717 JH	75	if ((flags & H_FORCE) == 0)
	76	printf("## Baudrate %d bps not supported\n",
	77	baudrate);
	78	return 1;
	79	}
	80	if ((flags & H_INTERACTIVE) != 0) {
	81	printf("## Switch baudrate to %d"
	82	" bps and press ENTER ...\n", baudrate);
	83	udelay(50000);
	84	}
	85
	86	gd->baudrate = baudrate;
32057717 JH	87
	88	serial_setbrg();
	89
	90	udelay(50000);
	91
	92	if ((flags & H_INTERACTIVE) != 0)
	93	while (1) {
c670aeee	94	if (getchar() == '\r')
32057717 JH	95	break;
	96	}
	97
	98	return 0;
	99	case env_op_delete:
	100	printf("## Baudrate may not be deleted\n");
	101	return 1;
	102	default:
	103	return 0;
	104	}
	105	}
	106	U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
	107
9cd2b9e4 MV	108	/**
	109	* serial_initfunc() - Forward declare of driver registration routine
	110	* @name: Name of the real driver registration routine.
	111	*
	112	* This macro expands onto forward declaration of a driver registration
	113	* routine, which is then used below in serial_initialize() function.
	114	* The declaration is made weak and aliases to serial_null() so in case
	115	* the driver is not compiled in, the function is still declared and can
	116	* be used, but aliases to serial_null() and thus is optimized away.
	117	*/
2a333aeb MV	118	#define serial_initfunc(name) \
	119	void name(void) \
	120	__attribute__((weak, alias("serial_null")));
	121
94a255df	122	serial_initfunc(atmel_serial_initialize);
94a255df	123	serial_initfunc(mcf_serial_initialize);
94a255df	124	serial_initfunc(mpc85xx_serial_initialize);
a943472c	125	serial_initfunc(mxc_serial_initialize);
94a255df	126	serial_initfunc(ns16550_serial_initialize);
39f61477	127	serial_initfunc(pl01x_serial_initialize);
94a255df	128	serial_initfunc(pxa_serial_initialize);
8bdd7efa	129	serial_initfunc(sh_serial_initialize);
44fa676e	130	serial_initfunc(mtk_serial_initialize);
f0eb1f61	131
9cd2b9e4 MV	132	/**
	133	* serial_register() - Register serial driver with serial driver core
	134	* @dev: Pointer to the serial driver structure
	135	*
	136	* This function registers the serial driver supplied via @dev with
	137	* serial driver core, thus making U-Boot aware of it and making it
	138	* available for U-Boot to use. On platforms that still require manual
	139	* relocation of constant variables, relocation of the supplied structure
	140	* is performed.
	141	*/
c52b4f79	142	void serial_register(struct serial_device *dev)
281e00a3	143	{
2e5167cc	144	#ifdef CONFIG_NEEDS_MANUAL_RELOC
f2760c4a MV	145	if (dev->start)
	146	dev->start += gd->reloc_off;
	147	if (dev->stop)
	148	dev->stop += gd->reloc_off;
	149	if (dev->setbrg)
	150	dev->setbrg += gd->reloc_off;
	151	if (dev->getc)
	152	dev->getc += gd->reloc_off;
	153	if (dev->tstc)
	154	dev->tstc += gd->reloc_off;
	155	if (dev->putc)
	156	dev->putc += gd->reloc_off;
	157	if (dev->puts)
	158	dev->puts += gd->reloc_off;
521af04d	159	#endif
281e00a3 WD	160
	161	dev->next = serial_devices;
	162	serial_devices = dev;
281e00a3 WD	163	}
281e00a3 WD	164
9cd2b9e4 MV	165	/**
	166	* serial_initialize() - Register all compiled-in serial port drivers
	167	*
	168	* This function registers all serial port drivers that are compiled
	169	* into the U-Boot binary with the serial core, thus making them
	170	* available to U-Boot to use. Lastly, this function assigns a default
	171	* serial port to the serial core. That serial port is then used as a
	172	* default output.
	173	*/
39a19223	174	int serial_initialize(void)
281e00a3	175	{
94a255df	176	atmel_serial_initialize();
94a255df	177	mcf_serial_initialize();
94a255df	178	mpc85xx_serial_initialize();
a943472c	179	mxc_serial_initialize();
94a255df	180	ns16550_serial_initialize();
39f61477	181	pl01x_serial_initialize();
94a255df	182	pxa_serial_initialize();
8bdd7efa	183	sh_serial_initialize();
44fa676e	184	mtk_serial_initialize();
7b953c51	185
a6e6f7f4	186	serial_assign(default_serial_console()->name);
39a19223 OP	187
39a19223 OP	188	return 0;
281e00a3 WD	189	}
281e00a3 WD	190
654f8d0f	191	static int serial_stub_start(struct stdio_dev *sdev)
709ea543 SG	192	{
	193	struct serial_device *dev = sdev->priv;
	194
	195	return dev->start();
	196	}
	197
654f8d0f	198	static int serial_stub_stop(struct stdio_dev *sdev)
709ea543 SG	199	{
	200	struct serial_device *dev = sdev->priv;
	201
	202	return dev->stop();
	203	}
	204
654f8d0f	205	static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
709ea543 SG	206	{
	207	struct serial_device *dev = sdev->priv;
	208
	209	dev->putc(ch);
	210	}
	211
654f8d0f	212	static void serial_stub_puts(struct stdio_dev sdev, const char str)
709ea543 SG	213	{
	214	struct serial_device *dev = sdev->priv;
	215
	216	dev->puts(str);
	217	}
	218
49ddcf3e	219	static int serial_stub_getc(struct stdio_dev *sdev)
709ea543 SG	220	{
	221	struct serial_device *dev = sdev->priv;
	222
	223	return dev->getc();
	224	}
	225
49ddcf3e	226	static int serial_stub_tstc(struct stdio_dev *sdev)
709ea543 SG	227	{
	228	struct serial_device *dev = sdev->priv;
	229
	230	return dev->tstc();
	231	}
	232
9cd2b9e4 MV	233	/**
	234	* serial_stdio_init() - Register serial ports with STDIO core
	235	*
	236	* This function generates a proxy driver for each serial port driver.
	237	* These proxy drivers then register with the STDIO core, making the
	238	* serial drivers available as STDIO devices.
	239	*/
a6e6f7f4	240	void serial_stdio_init(void)
281e00a3	241	{
52cb4d4f	242	struct stdio_dev dev;
281e00a3 WD	243	struct serial_device *s = serial_devices;
281e00a3 WD	244
2ee66533	245	while (s) {
a6e6f7f4	246	memset(&dev, 0, sizeof(dev));
281e00a3	247
a6e6f7f4	248	strcpy(dev.name, s->name);
281e00a3 WD	249	dev.flags = DEV_FLAGS_OUTPUT \| DEV_FLAGS_INPUT;
281e00a3 WD	250
709ea543 SG	251	dev.start = serial_stub_start;
	252	dev.stop = serial_stub_stop;
	253	dev.putc = serial_stub_putc;
	254	dev.puts = serial_stub_puts;
	255	dev.getc = serial_stub_getc;
	256	dev.tstc = serial_stub_tstc;
addf9513	257	dev.priv = s;
281e00a3	258
a6e6f7f4	259	stdio_register(&dev);
281e00a3 WD	260
	261	s = s->next;
	262	}
	263	}
	264
9cd2b9e4 MV	265	/**
	266	* serial_assign() - Select the serial output device by name
	267	* @name: Name of the serial driver to be used as default output
	268	*
	269	* This function configures the serial output multiplexing by
	270	* selecting which serial device will be used as default. In case
	271	* the STDIO "serial" device is selected as stdin/stdout/stderr,
	272	* the serial device previously configured by this function will be
	273	* used for the particular operation.
	274	*
	275	* Returns 0 on success, negative on error.
	276	*/
7813ca9b	277	int serial_assign(const char *name)
281e00a3 WD	278	{
	279	struct serial_device *s;
	280
2ee66533	281	for (s = serial_devices; s; s = s->next) {
6d93e258 MV	282	if (strcmp(s->name, name))
	283	continue;
	284	serial_current = s;
	285	return 0;
281e00a3 WD	286	}
281e00a3 WD	287
6d93e258	288	return -EINVAL;
281e00a3 WD	289	}
281e00a3 WD	290
9cd2b9e4 MV	291	/**
	292	* serial_reinit_all() - Reinitialize all compiled-in serial ports
	293	*
	294	* This function reinitializes all serial ports that are compiled
	295	* into U-Boot by calling their serial_start() functions.
	296	*/
a6e6f7f4	297	void serial_reinit_all(void)
281e00a3 WD	298	{
	299	struct serial_device *s;
	300
a6e6f7f4	301	for (s = serial_devices; s; s = s->next)
89143fb3	302	s->start();
281e00a3 WD	303	}
281e00a3 WD	304
9cd2b9e4 MV	305	/**
	306	* get_current() - Return pointer to currently selected serial port
	307	*
	308	* This function returns a pointer to currently selected serial port.
	309	* The currently selected serial port is altered by serial_assign()
	310	* function.
	311	*
	312	* In case this function is called before relocation or before any serial
	313	* port is configured, this function calls default_serial_console() to
	314	* determine the serial port. Otherwise, the configured serial port is
	315	* returned.
	316	*
	317	* Returns pointer to the currently selected serial port on success,
	318	* NULL on error.
	319	*/
857c283e	320	static struct serial_device *get_current(void)
281e00a3	321	{
857c283e	322	struct serial_device *dev;
2ee66533	323
dee19416	324	if (!(gd->flags & GD_FLG_RELOC))
857c283e	325	dev = default_serial_console();
dee19416 MV	326	else if (!serial_current)
	327	dev = default_serial_console();
	328	else
	329	dev = serial_current;
857c283e	330
dee19416 MV	331	/* We must have a console device */
dee19416 MV	332	if (!dev) {
f1f1e9cb	333	#ifdef CONFIG_SPL_BUILD
dee19416 MV	334	puts("Cannot find console\n");
dee19416 MV	335	hang();
f1f1e9cb	336	#else
dee19416	337	panic("Cannot find console\n");
f1f1e9cb	338	#endif
dee19416 MV	339	}
dee19416 MV	340
857c283e SG	341	return dev;
857c283e SG	342	}
281e00a3	343
9cd2b9e4 MV	344	/**
	345	* serial_init() - Initialize currently selected serial port
	346	*
	347	* This function initializes the currently selected serial port. This
	348	* usually involves setting up the registers of that particular port,
	349	* enabling clock and such. This function uses the get_current() call
	350	* to determine which port is selected.
	351	*
	352	* Returns 0 on success, negative on error.
	353	*/
857c283e SG	354	int serial_init(void)
857c283e SG	355	{
093f79ab	356	gd->flags \|= GD_FLG_SERIAL_READY;
89143fb3	357	return get_current()->start();
281e00a3 WD	358	}
281e00a3 WD	359
9cd2b9e4 MV	360	/**
	361	* serial_setbrg() - Configure baud-rate of currently selected serial port
	362	*
	363	* This function configures the baud-rate of the currently selected
	364	* serial port. The baud-rate is retrieved from global data within
	365	* the serial port driver. This function uses the get_current() call
	366	* to determine which port is selected.
	367	*
	368	* Returns 0 on success, negative on error.
	369	*/
a6e6f7f4	370	void serial_setbrg(void)
281e00a3	371	{
857c283e	372	get_current()->setbrg();
281e00a3 WD	373	}
281e00a3 WD	374
9cd2b9e4 MV	375	/**
	376	* serial_getc() - Read character from currently selected serial port
	377	*
	378	* This function retrieves a character from currently selected serial
	379	* port. In case there is no character waiting on the serial port,
	380	* this function will block and wait for the character to appear. This
	381	* function uses the get_current() call to determine which port is
	382	* selected.
	383	*
	384	* Returns the character on success, negative on error.
	385	*/
a6e6f7f4	386	int serial_getc(void)
281e00a3	387	{
857c283e	388	return get_current()->getc();
281e00a3 WD	389	}
281e00a3 WD	390
9cd2b9e4 MV	391	/**
	392	* serial_tstc() - Test if data is available on currently selected serial port
	393	*
	394	* This function tests if one or more characters are available on
	395	* currently selected serial port. This function never blocks. This
	396	* function uses the get_current() call to determine which port is
	397	* selected.
	398	*
	399	* Returns positive if character is available, zero otherwise.
	400	*/
a6e6f7f4	401	int serial_tstc(void)
281e00a3	402	{
857c283e	403	return get_current()->tstc();
281e00a3 WD	404	}
281e00a3 WD	405
9cd2b9e4 MV	406	/**
	407	* serial_putc() - Output character via currently selected serial port
	408	* @c: Single character to be output from the serial port.
	409	*
	410	* This function outputs a character via currently selected serial
	411	* port. This character is passed to the serial port driver responsible
	412	* for controlling the hardware. The hardware may still be in process
	413	* of transmitting another character, therefore this function may block
	414	* for a short amount of time. This function uses the get_current()
	415	* call to determine which port is selected.
	416	*/
a6e6f7f4	417	void serial_putc(const char c)
281e00a3	418	{
857c283e	419	get_current()->putc(c);
281e00a3 WD	420	}
281e00a3 WD	421
9cd2b9e4 MV	422	/**
	423	* serial_puts() - Output string via currently selected serial port
	424	* @s: Zero-terminated string to be output from the serial port.
	425	*
	426	* This function outputs a zero-terminated string via currently
	427	* selected serial port. This function behaves as an accelerator
	428	* in case the hardware can queue multiple characters for transfer.
	429	* The whole string that is to be output is available to the function
	430	* implementing the hardware manipulation. Transmitting the whole
	431	* string may take some time, thus this function may block for some
	432	* amount of time. This function uses the get_current() call to
	433	* determine which port is selected.
	434	*/
a6e6f7f4	435	void serial_puts(const char *s)
281e00a3	436	{
857c283e	437	get_current()->puts(s);
281e00a3	438	}
7b826c2f	439
9cd2b9e4 MV	440	/**
	441	* default_serial_puts() - Output string by calling serial_putc() in loop
	442	* @s: Zero-terminated string to be output from the serial port.
	443	*
	444	* This function outputs a zero-terminated string by calling serial_putc()
	445	* in a loop. Most drivers do not support queueing more than one byte for
	446	* transfer, thus this function precisely implements their serial_puts().
	447	*
	448	* To optimize the number of get_current() calls, this function only
	449	* calls get_current() once and then directly accesses the putc() call
	450	* of the &struct serial_device .
	451	*/
bfb7d7a3 MV	452	void default_serial_puts(const char *s)
	453	{
	454	struct serial_device *dev = get_current();
	455	while (*s)
	456	dev->putc(*s++);
	457	}
	458
7b826c2f MF	459	#if CONFIG_POST & CONFIG_SYS_POST_UART
	460	static const int bauds[] = CONFIG_SYS_BAUDRATE_TABLE;
	461
9cd2b9e4 MV	462	/**
	463	* uart_post_test() - Test the currently selected serial port using POST
	464	* @flags: POST framework flags
	465	*
	466	* Do a loopback test of the currently selected serial port. This
	467	* function is only useful in the context of the POST testing framwork.
1b25e586	468	* The serial port is first configured into loopback mode and then
9cd2b9e4 MV	469	* characters are sent through it.
	470	*
	471	* Returns 0 on success, value otherwise.
	472	*/
7b826c2f MF	473	/* Mark weak until post/cpu/.../uart.c migrate over */
	474	__weak
	475	int uart_post_test(int flags)
	476	{
	477	unsigned char c;
	478	int ret, saved_baud, b;
	479	struct serial_device saved_dev, s;
7b826c2f MF	480
	481	/* Save current serial state */
	482	ret = 0;
	483	saved_dev = serial_current;
8e261575	484	saved_baud = gd->baudrate;
7b826c2f MF	485
	486	for (s = serial_devices; s; s = s->next) {
	487	/* If this driver doesn't support loop back, skip it */
	488	if (!s->loop)
	489	continue;
	490
	491	/* Test the next device */
	492	serial_current = s;
	493
	494	ret = serial_init();
	495	if (ret)
	496	goto done;
	497
	498	/* Consume anything that happens to be queued */
	499	while (serial_tstc())
	500	serial_getc();
	501
	502	/* Enable loop back */
	503	s->loop(1);
	504
	505	/* Test every available baud rate */
	506	for (b = 0; b < ARRAY_SIZE(bauds); ++b) {
8e261575	507	gd->baudrate = bauds[b];
7b826c2f MF	508	serial_setbrg();
	509
	510	/*
	511	* Stick to printable chars to avoid issues:
	512	* - terminal corruption
	513	* - serial program reacting to sequences and sending
	514	* back random extra data
	515	* - most serial drivers add in extra chars (like \r\n)
	516	*/
	517	for (c = 0x20; c < 0x7f; ++c) {
	518	/* Send it out */
	519	serial_putc(c);
	520
	521	/* Make sure it's the same one */
	522	ret = (c != serial_getc());
	523	if (ret) {
	524	s->loop(0);
	525	goto done;
	526	}
	527
	528	/* Clean up the output in case it was sent */
	529	serial_putc('\b');
	530	ret = ('\b' != serial_getc());
	531	if (ret) {
	532	s->loop(0);
	533	goto done;
	534	}
	535	}
	536	}
	537
	538	/* Disable loop back */
	539	s->loop(0);
	540
89143fb3 MV	541	/* XXX: There is no serial_stop() !? */
	542	if (s->stop)
	543	s->stop();
7b826c2f MF	544	}
	545
	546	done:
	547	/* Restore previous serial state */
	548	serial_current = saved_dev;
8e261575	549	gd->baudrate = saved_baud;
7b826c2f MF	550	serial_reinit_all();
	551	serial_setbrg();
	552
	553	return ret;
	554	}
	555	#endif