u-boot/drivers/serial/serial-uclass.c
Simon Glass e4d6ab0c2c x86: Allow use of serial soon after relocation
At present on x86 machines with use cache-as-RAM, the memory goes away just
before board_init_r() is called. This means that serial drivers are
no-longer unavailable, until initr_dm() it called, etc.

Any attempt to use printf() within this period will cause a hang.

To fix this, mark the serial devices as 'unavailable' when it is no-longer
available. Bring it back when serial_initialize() is called. This means that
the debug UART will be used instead for this period.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2016-03-17 10:27:24 +08:00

362 lines
7.3 KiB
C

/*
* Copyright (c) 2014 The Chromium OS Authors.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <environment.h>
#include <errno.h>
#include <fdtdec.h>
#include <os.h>
#include <serial.h>
#include <stdio_dev.h>
#include <watchdog.h>
#include <dm/lists.h>
#include <dm/device-internal.h>
DECLARE_GLOBAL_DATA_PTR;
/*
* Table with supported baudrates (defined in config_xyz.h)
*/
static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;
#ifndef CONFIG_SYS_MALLOC_F_LEN
#error "Serial is required before relocation - define CONFIG_SYS_MALLOC_F_LEN to make this work"
#endif
static void serial_find_console_or_panic(void)
{
const void *blob = gd->fdt_blob;
struct udevice *dev;
int node;
if (CONFIG_IS_ENABLED(OF_CONTROL) && blob) {
/* Check for a chosen console */
node = fdtdec_get_chosen_node(blob, "stdout-path");
if (node < 0) {
const char *str, *p, *name;
/*
* Deal with things like
* stdout-path = "serial0:115200n8";
*
* We need to look up the alias and then follow it to
* the correct node.
*/
str = fdtdec_get_chosen_prop(blob, "stdout-path");
if (str) {
p = strchr(str, ':');
name = fdt_get_alias_namelen(blob, str,
p ? p - str : strlen(str));
if (name)
node = fdt_path_offset(blob, name);
}
}
if (node < 0)
node = fdt_path_offset(blob, "console");
if (!uclass_get_device_by_of_offset(UCLASS_SERIAL, node,
&dev)) {
gd->cur_serial_dev = dev;
return;
}
/*
* If the console is not marked to be bound before relocation,
* bind it anyway.
*/
if (node > 0 &&
!lists_bind_fdt(gd->dm_root, blob, node, &dev)) {
if (!device_probe(dev)) {
gd->cur_serial_dev = dev;
return;
}
}
}
if (!SPL_BUILD || !CONFIG_IS_ENABLED(OF_CONTROL) || !blob) {
/*
* Try to use CONFIG_CONS_INDEX if available (it is numbered
* from 1!).
*
* Failing that, get the device with sequence number 0, or in
* extremis just the first serial device we can find. But we
* insist on having a console (even if it is silent).
*/
#ifdef CONFIG_CONS_INDEX
#define INDEX (CONFIG_CONS_INDEX - 1)
#else
#define INDEX 0
#endif
if (!uclass_get_device_by_seq(UCLASS_SERIAL, INDEX, &dev) ||
!uclass_get_device(UCLASS_SERIAL, INDEX, &dev) ||
(!uclass_first_device(UCLASS_SERIAL, &dev) && dev)) {
gd->cur_serial_dev = dev;
return;
}
#undef INDEX
}
#ifdef CONFIG_REQUIRE_SERIAL_CONSOLE
panic_str("No serial driver found");
#endif
}
/* Called prior to relocation */
int serial_init(void)
{
serial_find_console_or_panic();
gd->flags |= GD_FLG_SERIAL_READY;
return 0;
}
/* Called after relocation */
void serial_initialize(void)
{
serial_init();
}
static void _serial_putc(struct udevice *dev, char ch)
{
struct dm_serial_ops *ops = serial_get_ops(dev);
int err;
if (ch == '\n')
_serial_putc(dev, '\r');
do {
err = ops->putc(dev, ch);
} while (err == -EAGAIN);
}
static void _serial_puts(struct udevice *dev, const char *str)
{
while (*str)
_serial_putc(dev, *str++);
}
static int _serial_getc(struct udevice *dev)
{
struct dm_serial_ops *ops = serial_get_ops(dev);
int err;
do {
err = ops->getc(dev);
if (err == -EAGAIN)
WATCHDOG_RESET();
} while (err == -EAGAIN);
return err >= 0 ? err : 0;
}
static int _serial_tstc(struct udevice *dev)
{
struct dm_serial_ops *ops = serial_get_ops(dev);
if (ops->pending)
return ops->pending(dev, true);
return 1;
}
void serial_putc(char ch)
{
if (gd->cur_serial_dev)
_serial_putc(gd->cur_serial_dev, ch);
}
void serial_puts(const char *str)
{
if (gd->cur_serial_dev)
_serial_puts(gd->cur_serial_dev, str);
}
int serial_getc(void)
{
if (!gd->cur_serial_dev)
return 0;
return _serial_getc(gd->cur_serial_dev);
}
int serial_tstc(void)
{
if (!gd->cur_serial_dev)
return 0;
return _serial_tstc(gd->cur_serial_dev);
}
void serial_setbrg(void)
{
struct dm_serial_ops *ops;
if (!gd->cur_serial_dev)
return;
ops = serial_get_ops(gd->cur_serial_dev);
if (ops->setbrg)
ops->setbrg(gd->cur_serial_dev, gd->baudrate);
}
void serial_stdio_init(void)
{
}
#if defined(CONFIG_DM_STDIO) && CONFIG_IS_ENABLED(SERIAL_PRESENT)
static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
{
_serial_putc(sdev->priv, ch);
}
#endif
void serial_stub_puts(struct stdio_dev *sdev, const char *str)
{
_serial_puts(sdev->priv, str);
}
int serial_stub_getc(struct stdio_dev *sdev)
{
return _serial_getc(sdev->priv);
}
int serial_stub_tstc(struct stdio_dev *sdev)
{
return _serial_tstc(sdev->priv);
}
/**
* 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);
#if CONFIG_IS_ENABLED(SERIAL_PRESENT)
static int serial_post_probe(struct udevice *dev)
{
struct dm_serial_ops *ops = serial_get_ops(dev);
#ifdef CONFIG_DM_STDIO
struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
struct stdio_dev sdev;
#endif
int ret;
#if defined(CONFIG_NEEDS_MANUAL_RELOC)
if (ops->setbrg)
ops->setbrg += gd->reloc_off;
if (ops->getc)
ops->getc += gd->reloc_off;
if (ops->putc)
ops->putc += gd->reloc_off;
if (ops->pending)
ops->pending += gd->reloc_off;
if (ops->clear)
ops->clear += gd->reloc_off;
#if CONFIG_POST & CONFIG_SYS_POST_UART
if (ops->loop)
ops->loop += gd->reloc_off
#endif
#endif
/* Set the baud rate */
if (ops->setbrg) {
ret = ops->setbrg(dev, gd->baudrate);
if (ret)
return ret;
}
#ifdef CONFIG_DM_STDIO
if (!(gd->flags & GD_FLG_RELOC))
return 0;
memset(&sdev, '\0', sizeof(sdev));
strncpy(sdev.name, dev->name, sizeof(sdev.name));
sdev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
sdev.priv = dev;
sdev.putc = serial_stub_putc;
sdev.puts = serial_stub_puts;
sdev.getc = serial_stub_getc;
sdev.tstc = serial_stub_tstc;
stdio_register_dev(&sdev, &upriv->sdev);
#endif
return 0;
}
static int serial_pre_remove(struct udevice *dev)
{
#ifdef CONFIG_SYS_STDIO_DEREGISTER
struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
if (stdio_deregister_dev(upriv->sdev, 0))
return -EPERM;
#endif
return 0;
}
UCLASS_DRIVER(serial) = {
.id = UCLASS_SERIAL,
.name = "serial",
.flags = DM_UC_FLAG_SEQ_ALIAS,
.post_probe = serial_post_probe,
.pre_remove = serial_pre_remove,
.per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
};
#endif