serial_efi.c
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/*
* Copyright (c) 2015 Google, Inc
* Written by Simon Glass <sjg@chromium.org>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <debug_uart.h>
#include <dm.h>
#include <efi.h>
#include <efi_api.h>
#include <errno.h>
#include <fdtdec.h>
#include <linux/compiler.h>
#include <asm/io.h>
#include <serial.h>
/* Information about the efi console */
struct serial_efi_priv {
struct efi_simple_input_interface *con_in;
struct efi_simple_text_output_protocol *con_out;
struct efi_input_key key;
bool have_key;
};
int serial_efi_setbrg(struct udevice *dev, int baudrate)
{
return 0;
}
static int serial_efi_get_key(struct serial_efi_priv *priv)
{
int ret;
if (priv->have_key)
return 0;
ret = priv->con_in->read_key_stroke(priv->con_in, &priv->key);
if (ret == EFI_NOT_READY)
return -EAGAIN;
else if (ret != EFI_SUCCESS)
return -EIO;
priv->have_key = true;
return 0;
}
static int serial_efi_getc(struct udevice *dev)
{
struct serial_efi_priv *priv = dev_get_priv(dev);
int ret, ch;
ret = serial_efi_get_key(priv);
if (ret)
return ret;
priv->have_key = false;
ch = priv->key.unicode_char;
/*
* Unicode char 8 (for backspace) is never returned. Instead we get a
* key scan code of 8. Handle this so that backspace works correctly
* in the U-Boot command line.
*/
if (!ch && priv->key.scan_code == 8)
ch = 8;
debug(" [%x %x %x] ", ch, priv->key.unicode_char, priv->key.scan_code);
return ch;
}
static int serial_efi_putc(struct udevice *dev, const char ch)
{
struct serial_efi_priv *priv = dev_get_priv(dev);
uint16_t ucode[2];
int ret;
ucode[0] = ch;
ucode[1] = '\0';
ret = priv->con_out->output_string(priv->con_out, ucode);
if (ret)
return -EIO;
return 0;
}
static int serial_efi_pending(struct udevice *dev, bool input)
{
struct serial_efi_priv *priv = dev_get_priv(dev);
int ret;
/* We assume that EFI will stall if its output buffer fills up */
if (!input)
return 0;
ret = serial_efi_get_key(priv);
if (ret == -EAGAIN)
return 0;
else if (ret)
return ret;
return 1;
}
/*
* There is nothing to init here since the EFI console is already running by
* the time we enter U-Boot.
*/
static inline void _debug_uart_init(void)
{
}
static inline void _debug_uart_putc(int ch)
{
struct efi_system_table *sys_table = efi_get_sys_table();
uint16_t ucode[2];
ucode[0] = ch;
ucode[1] = '\0';
sys_table->con_out->output_string(sys_table->con_out, ucode);
}
DEBUG_UART_FUNCS
static int serial_efi_probe(struct udevice *dev)
{
struct efi_system_table *table = efi_get_sys_table();
struct serial_efi_priv *priv = dev_get_priv(dev);
priv->con_in = table->con_in;
priv->con_out = table->con_out;
return 0;
}
static const struct dm_serial_ops serial_efi_ops = {
.putc = serial_efi_putc,
.getc = serial_efi_getc,
.pending = serial_efi_pending,
.setbrg = serial_efi_setbrg,
};
static const struct udevice_id serial_efi_ids[] = {
{ .compatible = "efi,uart" },
{ }
};
U_BOOT_DRIVER(serial_efi) = {
.name = "serial_efi",
.id = UCLASS_SERIAL,
.of_match = serial_efi_ids,
.priv_auto_alloc_size = sizeof(struct serial_efi_priv),
.probe = serial_efi_probe,
.ops = &serial_efi_ops,
.flags = DM_FLAG_PRE_RELOC,
};