u-boot/drivers/serial/serial.c
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

544 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2004
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*/
#include <common.h>
#include <environment.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
*
* This will check for a valid baudrate and only apply it if valid.
*/
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(au1x00_serial_initialize);
serial_initfunc(mcf_serial_initialize);
serial_initfunc(mpc85xx_serial_initialize);
serial_initfunc(mpc8xx_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_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();
au1x00_serial_initialize();
mcf_serial_initialize();
mpc85xx_serial_initialize();
mpc8xx_serial_initialize();
mxc_serial_initialize();
ns16550_serial_initialize();
pl01x_serial_initialize();
pxa_serial_initialize();
sh_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