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// 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 = dectoul(value, NULL);
/* 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