UART: Moving to fifo implementation and loop back example

examples/uart/Makefile

@@ -0,0 +1,4 @@
+BOARD ?= arduino_101
+CONF_FILE = prj.conf
+
+include ${ZEPHYR_BASE}/Makefile.inc

examples/uart/prj.conf

@@ -0,0 +1,14 @@
+CONFIG_STDOUT_CONSOLE=y
+CONFIG_CONSOLE_HANDLER=y
+CONFIG_CONSOLE_HANDLER_SHELL=y
+CONFIG_NANO_TIMERS=y
+CONFIG_NANO_TIMEOUTS=y
+CONFIG_SERIAL=y
+CONFIG_UART_QMSI=y
+CONFIG_UART_QMSI_1=y
+CONFIG_MRAA=y
+CONFIG_MRAA_UART=y
+CONFIG_NEWLIB_LIBC=y
+CONFIG_UART_LINE_CTRL=y
+#CONFIG_UART_QMSI_1_BAUDRATE=9600
+CONFIG_MRAA=y

examples/uart/src/Makefile

@@ -0,0 +1 @@
+obj-y = main.o

examples/uart/src/main.c

@@ -0,0 +1,76 @@
+/*
+ * Author: Abhishek Malik <[email protected]>
+ * Copyright (c) 2016 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include "version.h"
+#include <device.h>
+#include <mraa/uart.h>
+#include <string.h>
+#include <sys_clock.h>
+#include <zephyr.h>
+
+#define UART_DEVICE "UART_1"
+#define SLEEPTICKS SECONDS(1)
+
+#if defined(CONFIG_STDOUT_CONSOLE)
+#include <stdio.h>
+#define PRINT printf
+#else
+#include <misc/printk.h>
+#define PRINT printk
+#endif
+
+uint8_t buffer[] = {0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38};
+uint8_t ret_buf[8] = {0};
+
+void
+main(void)
+{
+    if (mraa_init() != MRAA_SUCCESS) {
+        printf("Unable to init MRAA");
+    }
+    mraa_uart_context dev = mraa_uart_init(1);
+    mraa_uart_set_baudrate(dev, 9600);
+
+    if (mraa_uart_write(dev, buffer, 8) != 8) {
+        printf("Error occured while writing bytes to UART\n");
+    }
+    //printf("\n");
+
+    mraa_boolean_t x = mraa_uart_data_available(dev, 100);
+    int ret_len = 0;
+    int i = 0;
+
+    if(x == true) {
+        ret_len = mraa_uart_read(dev, ret_buf, 8);
+        printf("\nReturned length: %d and returned buffer: \n", ret_len);
+        for (i = 0; i < 8; i++) {
+            printf("%c", (char)ret_buf[i]);
+        }
+        printf("\n");
+    } else {
+        printf("Unable to read anything back from the fifo\n");
+    }
+
+    mraa_uart_stop(dev);
+}

source/uart.c

@@ -51,6 +51,31 @@
 #define PRINT printk
 #endif
 
+static volatile bool data_transmitted;
+static volatile bool data_arrived;
+
+static void uart_interrupt_handler(struct device *dev) {
+    //printf("coming into interrupt handler\n");
+    uart_irq_update(dev);
+
+    if(uart_irq_tx_ready(dev)) {
+        data_transmitted = true;
+    }
+
+    if(uart_irq_rx_ready(dev)) {
+        //printf("rx is ready\n");
+        data_arrived = true;
+        uart_irq_rx_disable(dev);
+    }
+}
+
+void mraa_ms_delay(uint32_t time) {
+    struct k_timer timer;
+    k_timer_init(&timer, NULL, NULL);
+    k_timer_start(&timer, time, 0);
+    k_timer_status_sync(&timer);
+}
+
 mraa_uart_context
 mraa_uart_init(int uart)
 {
@@ -81,6 +106,10 @@ mraa_uart_init(int uart)
     dev->zdev = device_get_binding(UART_DEVICE);
     dev->block = 1;
 
+#if 1
+    uart_irq_callback_set(dev->zdev, uart_interrupt_handler);
+#endif
+
     return dev;
 }
 
@@ -93,22 +122,14 @@ mraa_uart_init_raw(const char* path)
 int
 mraa_uart_write(mraa_uart_context dev, const char* buf, size_t length)
 {
-    // this isn't the expected implementation, it should be length
-    // instead of length+1. However, the output gets completely
-    // screwed up with the actual length. Need to look into this
-    // to find RC and fix. Current implementation works though.
-    unsigned char ret[length + 1];
-    unsigned char temp;
-    int i = 0;
-    for (i = 0; i < length + 1; i++) {
-        temp = buf[i];
-        ret[i] = uart_poll_out(dev->zdev, temp);
-        if (ret[i] != temp) {
-            return i;
-        }
-    }
+    int i;
+    data_transmitted = false;
+
+    uart_irq_tx_enable(dev->zdev);
+    i = uart_fifo_fill(dev->zdev, buf, length);
+    uart_irq_tx_disable(dev->zdev);
 
-    return length;
+    return i;
 }
 
 mraa_result_t
@@ -145,20 +166,9 @@ mraa_uart_set_flowcontrol(mraa_uart_context dev, mraa_boolean_t xonxoff, mraa_bo
 int
 mraa_uart_read(mraa_uart_context dev, char* buf, size_t length)
 {
-    unsigned char store;
-    int ret, i = 0;
-    for (i = 0; i < length; i++) {
-        ret = uart_poll_in(dev->zdev, &store);
-        if (ret == -1) {
-            return i;
-        } else if (ret == 0) {
-            buf[i] = store;
-        } else {
-            return i;
-        }
-    }
+    data_arrived = false;
 
-    return length;
+    return uart_fifo_read(dev->zdev, buf, length);
 }
 
 // currently not implemented/ to be implemented once there is more clarity about zephyr API
@@ -201,5 +211,18 @@ mraa_uart_stop(mraa_uart_context dev)
 mraa_boolean_t
 mraa_uart_data_available(mraa_uart_context dev, unsigned int millis)
 {
-    return MRAA_ERROR_FEATURE_NOT_IMPLEMENTED;
+    int counter = 0;
+    uart_irq_rx_enable(dev->zdev);
+
+    while(data_arrived == false && counter < millis) {
+        counter++;
+        mraa_ms_delay(1);
+    }
+
+    uart_irq_rx_disable(dev->zdev);
+
+    if(data_arrived == true)
+        return true;
+    else
+        return false;
 }