sandbox.c
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/*
* Copyright (c) 2011 The Chromium OS Authors.
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* This provide a test serial port. It provides an emulated serial port where
* a test program and read out the serial output and inject serial input for
* U-Boot.
*/
#include <common.h>
#include <os.h>
#include <serial.h>
#include <linux/compiler.h>
/*
*
* serial_buf: A buffer that holds keyboard characters for the
* Sandbox U-boot.
*
* invariants:
* serial_buf_write == serial_buf_read -> empty buffer
* (serial_buf_write + 1) % 16 == serial_buf_read -> full buffer
*/
static char serial_buf[16];
static unsigned int serial_buf_write;
static unsigned int serial_buf_read;
static int sandbox_serial_init(void)
{
os_tty_raw(0);
return 0;
}
static void sandbox_serial_setbrg(void)
{
}
static void sandbox_serial_putc(const char ch)
{
os_write(1, &ch, 1);
}
static void sandbox_serial_puts(const char *str)
{
os_write(1, str, strlen(str));
}
static unsigned int increment_buffer_index(unsigned int index)
{
return (index + 1) % ARRAY_SIZE(serial_buf);
}
static int sandbox_serial_tstc(void)
{
const unsigned int next_index =
increment_buffer_index(serial_buf_write);
ssize_t count;
os_usleep(100);
if (next_index == serial_buf_read)
return 1; /* buffer full */
count = os_read_no_block(0, &serial_buf[serial_buf_write], 1);
if (count == 1)
serial_buf_write = next_index;
return serial_buf_write != serial_buf_read;
}
static int sandbox_serial_getc(void)
{
int result;
while (!sandbox_serial_tstc())
; /* buffer empty */
result = serial_buf[serial_buf_read];
serial_buf_read = increment_buffer_index(serial_buf_read);
return result;
}
static struct serial_device sandbox_serial_drv = {
.name = "sandbox_serial",
.start = sandbox_serial_init,
.stop = NULL,
.setbrg = sandbox_serial_setbrg,
.putc = sandbox_serial_putc,
.puts = sandbox_serial_puts,
.getc = sandbox_serial_getc,
.tstc = sandbox_serial_tstc,
};
void sandbox_serial_initialize(void)
{
serial_register(&sandbox_serial_drv);
}
__weak struct serial_device *default_serial_console(void)
{
return &sandbox_serial_drv;
}