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https://github.com/brain-hackers/u-boot-brain
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![Simon Glass](/assets/img/avatar_default.png)
In very very space-constrained devices even the full UART driver is too large. In this case the debug UART can still be used in some cases. Add options to enable the UART driver in SPL and U-Boot proper. Enable both options by default. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Thomas Chou <thomas@wytron.com.tw>
361 lines
7.3 KiB
C
361 lines
7.3 KiB
C
/*
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* Copyright (c) 2014 The Chromium OS Authors.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <dm.h>
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#include <environment.h>
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#include <errno.h>
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#include <fdtdec.h>
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#include <os.h>
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#include <serial.h>
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#include <stdio_dev.h>
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#include <watchdog.h>
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#include <dm/lists.h>
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#include <dm/device-internal.h>
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DECLARE_GLOBAL_DATA_PTR;
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/*
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* Table with supported baudrates (defined in config_xyz.h)
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*/
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static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;
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#ifndef CONFIG_SYS_MALLOC_F_LEN
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#error "Serial is required before relocation - define CONFIG_SYS_MALLOC_F_LEN to make this work"
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#endif
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static void serial_find_console_or_panic(void)
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{
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const void *blob = gd->fdt_blob;
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struct udevice *dev;
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int node;
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if (CONFIG_IS_ENABLED(OF_CONTROL) && blob) {
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/* Check for a chosen console */
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node = fdtdec_get_chosen_node(blob, "stdout-path");
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if (node < 0) {
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const char *str, *p, *name;
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/*
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* Deal with things like
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* stdout-path = "serial0:115200n8";
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*
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* We need to look up the alias and then follow it to
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* the correct node.
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*/
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str = fdtdec_get_chosen_prop(blob, "stdout-path");
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if (str) {
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p = strchr(str, ':');
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name = fdt_get_alias_namelen(blob, str,
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p ? p - str : strlen(str));
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if (name)
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node = fdt_path_offset(blob, name);
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}
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}
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if (node < 0)
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node = fdt_path_offset(blob, "console");
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if (!uclass_get_device_by_of_offset(UCLASS_SERIAL, node,
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&dev)) {
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gd->cur_serial_dev = dev;
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return;
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}
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/*
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* If the console is not marked to be bound before relocation,
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* bind it anyway.
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*/
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if (node > 0 &&
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!lists_bind_fdt(gd->dm_root, blob, node, &dev)) {
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if (!device_probe(dev)) {
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gd->cur_serial_dev = dev;
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return;
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}
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}
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}
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if (!SPL_BUILD || !CONFIG_IS_ENABLED(OF_CONTROL) || !blob) {
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/*
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* Try to use CONFIG_CONS_INDEX if available (it is numbered
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* from 1!).
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*
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* Failing that, get the device with sequence number 0, or in
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* extremis just the first serial device we can find. But we
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* insist on having a console (even if it is silent).
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*/
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#ifdef CONFIG_CONS_INDEX
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#define INDEX (CONFIG_CONS_INDEX - 1)
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#else
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#define INDEX 0
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#endif
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if (!uclass_get_device_by_seq(UCLASS_SERIAL, INDEX, &dev) ||
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!uclass_get_device(UCLASS_SERIAL, INDEX, &dev) ||
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(!uclass_first_device(UCLASS_SERIAL, &dev) && dev)) {
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gd->cur_serial_dev = dev;
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return;
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}
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#undef INDEX
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}
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#ifdef CONFIG_REQUIRE_SERIAL_CONSOLE
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panic_str("No serial driver found");
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#endif
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}
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/* Called prior to relocation */
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int serial_init(void)
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{
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serial_find_console_or_panic();
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gd->flags |= GD_FLG_SERIAL_READY;
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return 0;
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}
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/* Called after relocation */
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void serial_initialize(void)
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{
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serial_find_console_or_panic();
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}
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static void _serial_putc(struct udevice *dev, char ch)
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{
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struct dm_serial_ops *ops = serial_get_ops(dev);
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int err;
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do {
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err = ops->putc(dev, ch);
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} while (err == -EAGAIN);
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if (ch == '\n')
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_serial_putc(dev, '\r');
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}
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static void _serial_puts(struct udevice *dev, const char *str)
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{
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while (*str)
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_serial_putc(dev, *str++);
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}
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static int _serial_getc(struct udevice *dev)
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{
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struct dm_serial_ops *ops = serial_get_ops(dev);
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int err;
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do {
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err = ops->getc(dev);
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if (err == -EAGAIN)
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WATCHDOG_RESET();
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} while (err == -EAGAIN);
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return err >= 0 ? err : 0;
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}
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static int _serial_tstc(struct udevice *dev)
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{
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struct dm_serial_ops *ops = serial_get_ops(dev);
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if (ops->pending)
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return ops->pending(dev, true);
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return 1;
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}
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void serial_putc(char ch)
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{
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if (gd->cur_serial_dev)
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_serial_putc(gd->cur_serial_dev, ch);
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}
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void serial_puts(const char *str)
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{
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if (gd->cur_serial_dev)
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_serial_puts(gd->cur_serial_dev, str);
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}
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int serial_getc(void)
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{
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if (!gd->cur_serial_dev)
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return 0;
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return _serial_getc(gd->cur_serial_dev);
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}
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int serial_tstc(void)
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{
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if (!gd->cur_serial_dev)
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return 0;
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return _serial_tstc(gd->cur_serial_dev);
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}
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void serial_setbrg(void)
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{
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struct dm_serial_ops *ops;
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if (!gd->cur_serial_dev)
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return;
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ops = serial_get_ops(gd->cur_serial_dev);
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if (ops->setbrg)
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ops->setbrg(gd->cur_serial_dev, gd->baudrate);
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}
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void serial_stdio_init(void)
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{
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}
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#if defined(CONFIG_DM_STDIO) && CONFIG_IS_ENABLED(SERIAL_PRESENT)
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static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
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{
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_serial_putc(sdev->priv, ch);
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}
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#endif
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void serial_stub_puts(struct stdio_dev *sdev, const char *str)
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{
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_serial_puts(sdev->priv, str);
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}
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int serial_stub_getc(struct stdio_dev *sdev)
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{
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return _serial_getc(sdev->priv);
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}
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int serial_stub_tstc(struct stdio_dev *sdev)
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{
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return _serial_tstc(sdev->priv);
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}
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/**
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* on_baudrate() - Update the actual baudrate when the env var changes
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*
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* This will check for a valid baudrate and only apply it if valid.
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*/
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static int on_baudrate(const char *name, const char *value, enum env_op op,
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int flags)
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{
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int i;
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int baudrate;
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switch (op) {
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case env_op_create:
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case env_op_overwrite:
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/*
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* Switch to new baudrate if new baudrate is supported
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*/
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baudrate = simple_strtoul(value, NULL, 10);
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/* Not actually changing */
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if (gd->baudrate == baudrate)
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return 0;
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for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
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if (baudrate == baudrate_table[i])
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break;
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}
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if (i == ARRAY_SIZE(baudrate_table)) {
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if ((flags & H_FORCE) == 0)
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printf("## Baudrate %d bps not supported\n",
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baudrate);
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return 1;
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}
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if ((flags & H_INTERACTIVE) != 0) {
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printf("## Switch baudrate to %d bps and press ENTER ...\n",
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baudrate);
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udelay(50000);
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}
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gd->baudrate = baudrate;
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serial_setbrg();
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udelay(50000);
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if ((flags & H_INTERACTIVE) != 0)
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while (1) {
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if (getc() == '\r')
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break;
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}
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return 0;
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case env_op_delete:
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printf("## Baudrate may not be deleted\n");
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return 1;
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default:
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return 0;
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}
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}
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U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
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#if CONFIG_IS_ENABLED(SERIAL_PRESENT)
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static int serial_post_probe(struct udevice *dev)
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{
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struct dm_serial_ops *ops = serial_get_ops(dev);
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#ifdef CONFIG_DM_STDIO
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struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
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struct stdio_dev sdev;
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#endif
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int ret;
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#if defined(CONFIG_NEEDS_MANUAL_RELOC)
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if (ops->setbrg)
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ops->setbrg += gd->reloc_off;
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if (ops->getc)
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ops->getc += gd->reloc_off;
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if (ops->putc)
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ops->putc += gd->reloc_off;
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if (ops->pending)
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ops->pending += gd->reloc_off;
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if (ops->clear)
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ops->clear += gd->reloc_off;
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#if CONFIG_POST & CONFIG_SYS_POST_UART
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if (ops->loop)
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ops->loop += gd->reloc_off
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#endif
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#endif
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/* Set the baud rate */
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if (ops->setbrg) {
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ret = ops->setbrg(dev, gd->baudrate);
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if (ret)
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return ret;
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}
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#ifdef CONFIG_DM_STDIO
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if (!(gd->flags & GD_FLG_RELOC))
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return 0;
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memset(&sdev, '\0', sizeof(sdev));
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strncpy(sdev.name, dev->name, sizeof(sdev.name));
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sdev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
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sdev.priv = dev;
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sdev.putc = serial_stub_putc;
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sdev.puts = serial_stub_puts;
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sdev.getc = serial_stub_getc;
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sdev.tstc = serial_stub_tstc;
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stdio_register_dev(&sdev, &upriv->sdev);
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#endif
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return 0;
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}
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static int serial_pre_remove(struct udevice *dev)
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{
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#ifdef CONFIG_SYS_STDIO_DEREGISTER
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struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
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if (stdio_deregister_dev(upriv->sdev, 0))
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return -EPERM;
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#endif
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return 0;
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}
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UCLASS_DRIVER(serial) = {
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.id = UCLASS_SERIAL,
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.name = "serial",
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.flags = DM_UC_FLAG_SEQ_ALIAS,
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.post_probe = serial_post_probe,
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.pre_remove = serial_pre_remove,
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.per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
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};
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#endif
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