/*
 * 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_PLATDATA)) {
                uclass_first_device(UCLASS_SERIAL, &dev);
                if (dev) {
                        gd->cur_serial_dev = dev;
                        return;
                }
        } else 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)
{
#if CONFIG_IS_ENABLED(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