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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.
*/
/* Common code to do UART buffering and printing */
#include <stdarg.h>
#include "console.h"
#include "task.h"
#include "timer.h"
#include "uart.h"
#include "util.h"
/* Buffer sizes; should be power of 2 */
#define TX_BUF_SIZE 512
#define RX_BUF_SIZE 128 /* suggest larger than 80 to copy&paste script. */
#define HISTORY_SIZE 8
/* The size limit of single command */
#define RX_LINE_SIZE 80
/* Macros to advance in the circular buffers */
#define TX_BUF_NEXT(i) (((i) + 1) & (TX_BUF_SIZE - 1))
#define RX_BUF_NEXT(i) (((i) + 1) & (RX_BUF_SIZE - 1))
#define RX_BUF_PREV(i) (((i) - 1) & (RX_BUF_SIZE - 1))
#define CMD_HIST_NEXT(i) (((i) + 1) & (HISTORY_SIZE - 1))
#define CMD_HIST_PREV(i) (((i) - 1) & (HISTORY_SIZE - 1))
/* Macro to calculate difference of pointers in the circular receive buffer. */
#define RX_BUF_DIFF(i, j) (((i) - (j)) & (RX_BUF_SIZE - 1))
/* Transmit and receive buffers */
static volatile char tx_buf[TX_BUF_SIZE];
static volatile int tx_buf_head;
static volatile int tx_buf_tail;
static volatile char rx_buf[RX_BUF_SIZE];
static volatile int rx_buf_head;
static volatile int rx_buf_tail;
static volatile char rx_cur_buf[RX_LINE_SIZE];
static volatile int rx_cur_buf_tail;
static volatile int rx_cur_buf_head;
static volatile int rx_cur_buf_ptr;
static int last_rx_was_cr;
static int in_escape;
static char esc_seq_char;
/* Command history */
struct cmd_history_t {
volatile int head;
volatile int tail;
};
static struct cmd_history_t cmd_history[HISTORY_SIZE];
static volatile int cmd_history_head;
static volatile int cmd_history_tail;
static volatile int cmd_history_ptr;
static int console_mode = 1;
/* TODO: should have an API to set raw mode for the UART. In raw
* mode, we don't do CRLF translation or echo input. */
/* Put a single character into the transmit buffer. Does not enable
* the transmit interrupt; assumes that happens elsewhere. Returns
* zero if the character was transmitted, 1 if it was dropped. */
static int __tx_char(int c)
{
int tx_buf_next;
/* Do newline to CRLF translation */
if (console_mode && c == '\n' && __tx_char('\r'))
return 1;
tx_buf_next = TX_BUF_NEXT(tx_buf_head);
if (tx_buf_next == tx_buf_tail)
return 1;
tx_buf[tx_buf_head] = c;
tx_buf_head = tx_buf_next;
return 0;
}
static void move_rx_ptr_fwd(void)
{
if (rx_cur_buf_ptr != rx_cur_buf_head) {
++rx_cur_buf_ptr;
uart_write_char(0x1B);
uart_write_char('[');
uart_write_char('1');
uart_write_char('C');
}
}
static void move_rx_ptr_bwd(void)
{
if (rx_cur_buf_ptr != 0) {
--rx_cur_buf_ptr;
uart_write_char(0x1B);
uart_write_char('[');
uart_write_char('1');
uart_write_char('D');
}
}
static void repeat_char(char c, int cnt)
{
while (cnt--)
uart_write_char(c);
}
static void handle_backspace(void)
{
if (rx_cur_buf_ptr != 0) {
/* Move texts after cursor and also update rx buffer. */
int ptr;
for (ptr = rx_cur_buf_ptr; ptr < rx_cur_buf_head; ++ptr) {
uart_write_char(rx_cur_buf[ptr]);
rx_cur_buf[ptr - 1] = rx_cur_buf[ptr];
}
/* Space over last character and move cursor back to correct
* position.
*/
uart_write_char(' ');
repeat_char('\b', ptr - rx_cur_buf_ptr + 1);
--rx_cur_buf_head;
--rx_cur_buf_ptr;
}
else
/* Cursor moves pass the first character. Move it back. */
uart_write_char(' ');
}
static void insert_char(char c)
{
int ptr;
/* On overflow, discard input */
if (rx_cur_buf_head == RX_LINE_SIZE)
return;
/* Move buffer ptr to the end if 'c' is new line */
if (c == '\n')
rx_cur_buf_ptr = rx_cur_buf_head;
/* Move text after cursor. */
for (ptr = rx_cur_buf_ptr; ptr < rx_cur_buf_head; ++ptr)
uart_write_char(rx_cur_buf[ptr]);
/* Insert character to rx buffer and move cursor to correct
* position.
*/
repeat_char('\b', ptr - rx_cur_buf_ptr);
for (ptr = rx_cur_buf_head; ptr > rx_cur_buf_ptr; --ptr)
rx_cur_buf[ptr] = rx_cur_buf[ptr - 1];
rx_cur_buf[rx_cur_buf_ptr] = c;
++rx_cur_buf_head;
++rx_cur_buf_ptr;
/* Insert character directly into rx_buf if not in console mode. */
if (!console_mode) {
rx_buf[rx_buf_head] = c;
rx_buf_head = RX_BUF_NEXT(rx_buf_head);
if (rx_buf_tail == rx_buf_head)
rx_buf_tail = RX_BUF_NEXT(rx_buf_tail);
}
}
static int rx_buf_space_available(void)
{
if (cmd_history_head == cmd_history_tail)
return RX_BUF_SIZE;
return RX_BUF_DIFF(cmd_history[cmd_history_tail].tail,
cmd_history[CMD_HIST_PREV(cmd_history_head)].head);
}
static void history_save(void)
{
int ptr;
int tail, head;
int hist_id;
/* If there is not enough space in rx buffer, discard the oldest
* history. */
while (rx_buf_space_available() < rx_cur_buf_head)
cmd_history_tail = CMD_HIST_NEXT(cmd_history_tail);
/* If history buffer is full, discard the oldest one */
hist_id = cmd_history_head;
cmd_history_head = CMD_HIST_NEXT(cmd_history_head);
if (cmd_history_head == cmd_history_tail)
cmd_history_tail = CMD_HIST_NEXT(cmd_history_tail);
/* Copy the current command, but we do not save the '\n' */
if (hist_id == cmd_history_tail)
tail = 0;
else
tail = RX_BUF_NEXT(cmd_history[CMD_HIST_PREV(hist_id)].head);
head = tail;
for (ptr = 0; ptr < rx_cur_buf_head; ++ptr, head = RX_BUF_NEXT(head))
rx_buf[head] = rx_cur_buf[ptr];
if (rx_buf[RX_BUF_PREV(head)] == '\n') {
head = RX_BUF_PREV(head);
rx_buf[head] = '\0';
}
cmd_history[hist_id].head = head;
cmd_history[hist_id].tail = tail;
}
static void history_load(int id)
{
int head = cmd_history[id].head;
int tail = cmd_history[id].tail;
int ptr;
cmd_history_ptr = id;
/* Move cursor back to begin of the line. */
repeat_char('\b', rx_cur_buf_ptr);
/* Load command and print it. */
for (ptr = tail, rx_cur_buf_ptr = 0; ptr != head;
ptr = RX_BUF_NEXT(ptr), ++rx_cur_buf_ptr) {
rx_cur_buf[rx_cur_buf_ptr] = rx_buf[ptr];
uart_write_char(rx_buf[ptr]);
}
/* If needed, space over the remaining text. */
if (rx_cur_buf_ptr < rx_cur_buf_head) {
repeat_char(' ', rx_cur_buf_head - rx_cur_buf_ptr);
repeat_char('\b', rx_cur_buf_head - rx_cur_buf_ptr);
}
rx_cur_buf_head = rx_cur_buf_ptr;
}
static void history_prev(void)
{
if (cmd_history_ptr == cmd_history_tail)
return;
/* Stash the current command if we are not currently using history.
* Prevent loading history if there is no space to stash current
* command. */
if (cmd_history_ptr == cmd_history_head) {
int last_id = CMD_HIST_PREV(cmd_history_head);
int last_len = RX_BUF_DIFF(cmd_history[last_id].head,
cmd_history[last_id].tail);
if (last_len + rx_cur_buf_head > RX_BUF_SIZE)
return;
history_save();
}
cmd_history_ptr = CMD_HIST_PREV(cmd_history_ptr);
history_load(cmd_history_ptr);
}
static void history_next(void)
{
if (cmd_history_ptr == cmd_history_head)
return;
cmd_history_ptr = CMD_HIST_NEXT(cmd_history_ptr);
history_load(cmd_history_ptr);
/* Remove the stashed command if we just loaded it. */
if (cmd_history_ptr == CMD_HIST_PREV(cmd_history_head))
cmd_history_head = cmd_history_ptr;
}
/* Helper for UART processing */
void uart_process(void)
{
/* Copy input from buffer until RX fifo empty */
while (uart_rx_available()) {
int c = uart_read_char();
/* Handle console mode echoing and translation */
if (console_mode) {
/* Translate CR and CRLF to LF (newline) */
if (c == '\r') {
last_rx_was_cr = 1;
c = '\n';
} else if (c == '\n' && last_rx_was_cr) {
last_rx_was_cr = 0;
continue;
} else {
last_rx_was_cr = 0;
}
/* Handle left and right key, and eat other terminal
* escape sequences (ESC [ ...).
* Would be really cool if we used arrow keys to edit
* command history, but for now it's sufficient just to
* keep them from causing problems. */
if (c == 0x1B) {
in_escape = 1;
esc_seq_char = c;
continue;
} else if (in_escape) {
if (esc_seq_char == 0x1B && c == '[')
esc_seq_char = '[';
else if (esc_seq_char == '[') {
if (c == 'A') /* Up key */
history_prev();
else if (c == 'B') /* Down key */
history_next();
else if (c == 'C') /* Right key */
move_rx_ptr_fwd();
else if (c == 'D') /* Left key */
move_rx_ptr_bwd();
esc_seq_char = 0;
}
else
esc_seq_char = 0;
if (isalpha(c) || c == '~') {
esc_seq_char = 0;
in_escape = 0;
}
continue;
}
/* Echo characters directly to the transmit FIFO so we
* don't interfere with the transmit buffer. */
if (c == '\n')
uart_write_char('\r');
uart_write_char(c);
/* Handle backspace if we can */
if (c == '\b') {
handle_backspace();
continue;
}
}
insert_char(c);
/* Call console callback on newline, if in console mode */
if (console_mode && c == '\n')
console_has_input();
}
/* Copy output from buffer until TX fifo full or output buffer empty */
while (uart_tx_ready() && (tx_buf_head != tx_buf_tail)) {
uart_write_char(tx_buf[tx_buf_tail]);
tx_buf_tail = TX_BUF_NEXT(tx_buf_tail);
}
/* If output buffer is empty, disable transmit interrupt */
if (tx_buf_tail == tx_buf_head)
uart_tx_stop();
}
void uart_set_console_mode(int enable)
{
console_mode = enable;
if (!enable)
rx_cur_buf_ptr = rx_cur_buf_head;
}
int uart_puts(const char *outstr)
{
/* Put all characters in the output buffer */
while (*outstr) {
if (__tx_char(*outstr++) != 0)
break;
}
if (uart_tx_stopped())
uart_tx_start();
/* Successful if we consumed all output */
return *outstr ? EC_ERROR_OVERFLOW : EC_SUCCESS;
}
int uart_vprintf(const char *format, va_list args)
{
static const char int_chars[] = "0123456789abcdef";
static const char error_str[] = "ERROR";
char intbuf[33];
/* Longest uint64 in decimal = 20
* longest uint32 in binary = 32
*/
int dropped_chars = 0;
int is_left;
int pad_zero;
int pad_width;
char *vstr;
int vlen;
while (*format && !dropped_chars) {
int c = *format++;
/* Copy normal characters */
if (c != '%') {
dropped_chars |= __tx_char(c);
continue;
}
/* Get first format character */
c = *format++;
/* Send "%" for "%%" input */
if (c == '%' || c == '\0') {
dropped_chars |= __tx_char('%');
continue;
}
/* Handle %c */
if (c == 'c') {
c = va_arg(args, int);
dropped_chars |= __tx_char(c);
continue;
}
/* Handle left-justification ("%-5s") */
is_left = (c == '-');
if (is_left)
c = *format++;
/* Handle padding with 0's */
pad_zero = (c == '0');
if (pad_zero)
c = *format++;
/* Count padding length */
pad_width = 0;
while (c >= '0' && c <= '9') {
pad_width = (10 * pad_width) + c - '0';
c = *format++;
}
if (pad_width > 80) {
/* Sanity check for width failed */
format = error_str;
continue;
}
if (c == 's') {
vstr = va_arg(args, char *);
if (vstr == NULL)
vstr = "(NULL)";
} else {
uint64_t v;
int is_negative = 0;
int is_64bit = 0;
int base = 10;
if (c == 'l') {
is_64bit = 1;
c = *format++;
}
/* Special-case: %T = current time */
if (c == 'T') {
v = get_time().val;
is_64bit = 1;
} else if (is_64bit) {
v = va_arg(args, uint64_t);
} else {
v = va_arg(args, uint32_t);
}
switch (c) {
case 'd':
if (is_64bit) {
if ((int64_t)v < 0) {
is_negative = 1;
if (v != (1ULL << 63))
v = -v;
}
} else {
if ((int)v < 0) {
is_negative = 1;
if (v != (1ULL << 31))
v = -(int)v;
}
}
break;
case 'u':
case 'T':
break;
case 'x':
case 'p':
base = 16;
break;
case 'b':
base = 2;
break;
default:
format = error_str;
}
if (format == error_str)
continue; /* Bad format specifier */
/* Convert integer to string, starting at end of
* buffer and working backwards. */
vstr = intbuf + sizeof(intbuf) - 1;
*(vstr) = '\0';
if (!v)
*(--vstr) = '0';
while (v)
*(--vstr) = int_chars[uint64divmod(&v, base)];
if (is_negative)
*(--vstr) = '-';
}
/* Copy string (or stringified integer) */
vlen = strlen(vstr);
while (vlen < pad_width && !is_left) {
dropped_chars |= __tx_char(pad_zero ? '0' : ' ');
vlen++;
}
while (*vstr)
dropped_chars |= __tx_char(*vstr++);
while (vlen < pad_width && is_left) {
dropped_chars |= __tx_char(' ');
vlen++;
}
}
if (uart_tx_stopped())
uart_tx_start();
/* Successful if we consumed all output */
return dropped_chars ? EC_ERROR_OVERFLOW : EC_SUCCESS;
}
int uart_printf(const char *format, ...)
{
int rv;
va_list args;
va_start(args, format);
rv = uart_vprintf(format, args);
va_end(args);
return rv;
}
/* For use when debugging verified boot. We could wrap it with a real function,
* but it's rarely needed and this doesn't add any extra code. We have to
* declare it here in order for this trick to work. */
void VbExDebug(const char *format, ...)
__attribute__((weak, alias("uart_printf")));
void uart_flush_output(void)
{
/* Wait for buffer to empty */
while (tx_buf_head != tx_buf_tail) {
/* It's possible we're in some other interrupt, and the
* previous context was doing a printf() or puts() but hadn't
* enabled the UART interrupt. Check if the interrupt is
* disabled, and if so, re-enable and trigger it. Note that
* this check is inside the while loop, so we'll be safe even
* if the context switches away from us to another partial
* printf() and back. */
if (uart_tx_stopped())
uart_tx_start();
}
/* Wait for transmit FIFO empty */
uart_tx_flush();
}
void uart_emergency_flush(void)
{
do {
/* Copy output from buffer until TX fifo full
* or output buffer empty
*/
while (uart_tx_ready() &&
(tx_buf_head != tx_buf_tail)) {
uart_write_char(tx_buf[tx_buf_tail]);
tx_buf_tail = TX_BUF_NEXT(tx_buf_tail);
}
/* Wait for transmit FIFO empty */
uart_tx_flush();
} while (tx_buf_head != tx_buf_tail);
}
void uart_flush_input(void)
{
/* Disable interrupts */
uart_disable_interrupt();
/* Empty the hardware FIFO */
uart_process();
/* Clear the input buffer */
rx_cur_buf_head = 0;
rx_buf_tail = rx_buf_head;
/* Re-enable interrupts */
uart_enable_interrupt();
}
int uart_peek(int c)
{
int index = -1;
int i = 0;
/* Disable interrupts while we pull characters out, because the
* interrupt handler can also modify the tail pointer. */
uart_disable_interrupt();
/* Call interrupt handler to empty the hardware FIFO. The minimum
* FIFO trigger depth is 1/8 (2 chars), so this is the only way to
* ensure we've pulled the very last character out of the FIFO. */
uart_process();
for (i = 0; i < rx_cur_buf_head; ++i) {
if (rx_cur_buf[i] == c) {
index = i;
break;
}
}
/* Re-enable interrupts */
uart_enable_interrupt();
return index;
}
int uart_getc(void)
{
int c;
/* Disable interrupts */
uart_disable_interrupt();
/* Call interrupt handler to empty the hardware FIFO */
uart_process();
if (rx_buf_tail == rx_buf_head) {
c = -1; /* No pending input */
} else {
c = rx_buf[rx_buf_tail];
rx_buf_tail = RX_BUF_NEXT(rx_buf_tail);
}
/* Re-enable interrupts */
uart_enable_interrupt();
return c;
}
int uart_gets(char *dest, int size)
{
int got = 0;
int c;
/* Disable interrupts while we pull characters out, because the
* interrupt handler can also modify the tail pointer. */
uart_disable_interrupt();
/* Call interrupt handler to empty the hardware FIFO */
uart_process();
/* Remove the stashed command if any. */
if (cmd_history_ptr != cmd_history_head)
cmd_history_head = CMD_HIST_PREV(cmd_history_head);
/* Record last command. */
if (!(rx_cur_buf_head == 1 && rx_cur_buf[0] == '\n'))
history_save();
cmd_history_ptr = cmd_history_head;
/* Read characters */
while (got < size - 1 && got < rx_cur_buf_head) {
c = rx_cur_buf[got];
dest[got++] = c;
if (c == '\n')
break; /* Stop on newline */
}
rx_cur_buf_ptr = 0;
rx_cur_buf_head = 0;
rx_cur_buf_tail = rx_cur_buf_head;
/* Re-enable interrupts */
uart_enable_interrupt();
/* Null-terminate */
dest[got] = '\0';
/* Return the length we got */
return got;
}
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