Console input support for emulator

This creates a separate thread that keeps reading characters from stdin
and feed to UART process.

BUG=chrome-os-partner:19235
TEST=Start up a emulator and type 'help'. See command list.
TEST=Pass all tests for 300 times.
BRANCH=None

Change-Id: I190c1d939b0b4ad0f8f0517d8d7b06f2f3df3832
Signed-off-by: Vic Yang <victoryang@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/57866
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

2 files changed, 60 insertions, 3 deletions

diff --git a/chip/host/uart.c b/chip/host/uart.c
index cbae79974b..9add50d4d2 100644
--- a/chip/host/uart.c
+++ b/chip/host/uart.c
@@ -5,10 +5,14 @@
 
 /* UART driver for emulator */
 
+#include <pthread.h>
 #include <stdio.h>
+#include <termio.h>
+#include <unistd.h>
 
 #include "board.h"
 #include "config.h"
+#include "queue.h"
 #include "task.h"
 #include "uart.h"
 
@@ -16,8 +20,24 @@ static int stopped;
 static int int_disabled;
 static int init_done;
 
+static pthread_t input_thread;
+
+#define INPUT_BUFFER_SIZE 16
+/* TODO: Guard these data with mutex lock when we have interrupt support. */
+static int char_available;
+static char cached_char_buf[INPUT_BUFFER_SIZE];
+static struct queue cached_char = {
+	.buf_bytes  = INPUT_BUFFER_SIZE,
+	.unit_bytes = sizeof(char),
+	.buf        = cached_char_buf,
+};
+
 static void trigger_interrupt(void)
 {
+	/*
+	 * TODO: Check global interrupt status when we have
+	 * interrupt support.
+	 */
 	if (!int_disabled)
 		uart_process();
 }
@@ -55,7 +75,7 @@ int uart_tx_ready(void)
 
 int uart_rx_available(void)
 {
-	return 0;
+	return char_available;
 }
 
 void uart_write_char(char c)
@@ -66,8 +86,10 @@ void uart_write_char(char c)
 
 int uart_read_char(void)
 {
-	/* Should never be called for now */
-	return 0;
+	char ret;
+	queue_remove_unit(&cached_char, &ret);
+	--char_available;
+	return ret;
 }
 
 void uart_disable_interrupt(void)
@@ -80,7 +102,39 @@ void uart_enable_interrupt(void)
 	int_disabled = 0;
 }
 
+void *uart_monitor_stdin(void *d)
+{
+	struct termios org_settings, new_settings;
+	char buf[INPUT_BUFFER_SIZE];
+	int rv;
+
+	tcgetattr(0, &org_settings);
+	new_settings = org_settings;
+	new_settings.c_lflag &= ~(ECHO | ICANON);
+	new_settings.c_cc[VTIME] = 0;
+	new_settings.c_cc[VMIN] = 1;
+
+	printf("Console input initialized\n");
+	while (1) {
+		tcsetattr(0, TCSANOW, &new_settings);
+		rv = read(0, buf, INPUT_BUFFER_SIZE);
+		if (queue_has_space(&cached_char, rv))
+			queue_add_units(&cached_char, buf, rv);
+		char_available = rv;
+		tcsetattr(0, TCSANOW, &org_settings);
+		/*
+		 * TODO: Trigger emulated interrupt when we have
+		 * interrupt support. Also, we will need a condition
+		 * variable to indicate the character has been read.
+		 */
+		trigger_interrupt();
+	}
+
+	return 0;
+}
+
 void uart_init(void)
 {
+	pthread_create(&input_thread, NULL, uart_monitor_stdin, NULL);
 	init_done = 1;
 }
diff --git a/core/host/main.c b/core/host/main.c
index ba8ec95dcf..f69107af4a 100644
--- a/core/host/main.c
+++ b/core/host/main.c
@@ -9,6 +9,7 @@
 #include "hooks.h"
 #include "task.h"
 #include "timer.h"
+#include "uart.h"
 
 int main(void)
 {
@@ -18,6 +19,8 @@ int main(void)
 
 	hook_init();
 
+	uart_init();
+
 	task_start();
 
 	return 0;