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/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* uart.h - UART module for Chrome EC */
#ifndef __CROS_EC_UART_H
#define __CROS_EC_UART_H
#include <stdarg.h> /* For va_list */
#include "common.h"
/* Initializes the UART module. */
int uart_init(void);
/* Return non-zero if UART init has completed. */
int uart_init_done(void);
/*****************************************************************************/
/* Output functions
*
* Output is buffered. If the buffer overflows, subsequent output is
* discarded. */
/* Put a null-terminated string to the UART, like fputs().
*
* Returns error if output was truncated. */
int uart_puts(const char *outstr);
/* Print formatted output to the UART, like printf().
*
* See printf.h for valid formatting codes. */
int uart_printf(const char *format, ...);
/* Print formatted output to the UART, like vprintf().
*
* See printf.h for valid formatting codes. */
int uart_vprintf(const char *format, va_list args);
/* Flushes output. Blocks until UART has transmitted all output. */
void uart_flush_output(void);
/*****************************************************************************/
/* Input functions
*
* Input is buffered. If the buffer overflows, the oldest input in
* the buffer is discarded to make room for the new input.
*
* Input lines may be terminated by CR ('\r'), LF ('\n'), or CRLF; all
* are translated to newline. */
/* Flushes input buffer, discarding all input. */
void uart_flush_input(void);
/* Non-destructively checks for a character in the input buffer.
*
* Returns the offset into the input buffer of character <c>, or -1 if
* it is not in the input buffer. */
int uart_peek(int c);
/* Reads a single character of input, similar to fgetc(). Returns the
* character, or -1 if no input waiting. */
int uart_getc(void);
/* Reads characters from the UART, similar to fgets().
*
* Reads input until one of the following conditions is met:
* (1) <size-1> characters have been read.
* (2) A newline ('\n') has been read.
* (3) The input buffer is empty.
*
* Condition (3) means this call never blocks. This is important
* because it prevents a race condition where the caller calls
* UartPeek() to see if input is waiting, or is notified by the
* callack that input is waiting, but then the input buffer overflows
* or someone else grabs the input before UartGets() is called.
*
* Characters are stored in <dest> and are null-terminated.
* Characters include the newline if present, so that the caller can
* distinguish between a complete line and a truncated one. If the
* input buffer is empty, a null-terminated empty string ("") is
* returned.
*
* Returns the number of characters read (not counting the terminating
* null). */
int uart_gets(char *dest, int size);
/* TODO: getc(), putc() equivalents? */
/*****************************************************************************/
/* Hardware UART driver functions */
/* Flushes the transmit FIFO. */
void uart_tx_flush(void);
/* Returns true if there is room to transmit a character immediatly. */
int uart_tx_ready(void);
/* Returns true if the UART has character available. */
int uart_rx_available(void);
/**
* Sends a character to the UART data register.
* If the transmit FIFO is full, this function blocks until there is space.
*
* c : byte to send.
*/
void uart_write_char(char c);
/**
* Reads and returns one char from the UART data register.
*
* Called when uart_rx_available once returns true.
*/
int uart_read_char(void);
/**
* Disables all UART related IRQs.
*
* To avoid concurrent accesses on UART management variables.
*/
void uart_disable_interrupt(void);
/* Re-enables UART IRQs. */
void uart_enable_interrupt(void);
/**
* Re-enables the UART transmit interrupt.
*
* It also forces triggering an interrupt if the hardware doesn't automatically
* trigger it when the transmit buffer was filled beforehand.
*/
void uart_tx_start(void);
/* Disables the UART transmit interrupt. */
void uart_tx_stop(void);
/* Returns true if the UART transmit interrupt is disabled */
int uart_tx_stopped(void);
/**
* Helper for UART processing.
* Read the input FIFO until empty, then fill the output FIFO until the transmit
* buffer is empty or the FIFO full.
*
* Designed to be called from the driver interrupt handler.
*/
void uart_process(void);
/*****************************************************************************/
/* COMx functions */
/* Enables comx interrupts */
void uart_comx_enable(void);
/* Returns non-zero if ok to put a character via uart_comx_putc(). */
int uart_comx_putc_ok(void);
/* Puts a character to the COMx UART interface. */
void uart_comx_putc(int c);
#endif /* __CROS_EC_UART_H */
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