Fix issue #52. Add esp/uart.h

core/include/esp/uart.h

@@ -0,0 +1,113 @@
+/** esp/uart.h
+ *
+ * Utility routines for working with UARTs
+ *
+ * Part of esp-open-rtos
+ * Copyright (C) 2015 Superhouse Automation Pty Ltd
+ * BSD Licensed as described in the file LICENSE
+ */
+#ifndef _ESP_UART_H
+#define _ESP_UART_H
+
+#include "esp/types.h"
+#include "esp/uart_regs.h"
+
+#define UART_FIFO_MAX 127
+
+/* Wait for at least `min_count` bytes of data to be available in the UART's
+ * receive FIFO
+ *
+ * Returns the number of bytes actually available for reading.
+ */
+static inline int uart_rxfifo_wait(int uart_num, int min_count) {
+    int count;
+    do {
+        count = FIELD2VAL(UART_STATUS_RXFIFO_COUNT, UART(uart_num).STATUS);
+    } while (count < min_count);
+    return count;
+}
+
+/* Wait for at least `min_count` bytes of space to be available in the UART's
+ * transmit FIFO
+ *
+ * Returns the number of bytes actually available in the write buffer.
+ */
+static inline int uart_txfifo_wait(int uart_num, int min_count) {
+    int count;
+    do {
+        count = UART_FIFO_MAX - FIELD2VAL(UART_STATUS_TXFIFO_COUNT, UART(uart_num).STATUS);
+    } while (count < min_count);
+    return count;
+}
+
+/* Read a character from the UART.  Block until a character is available for
+ * reading.
+ *
+ * Returns the character read.
+ */
+static inline int uart_getc(int uart_num) {
+    uart_rxfifo_wait(uart_num, 1);
+    return UART(uart_num).FIFO;
+}
+
+/* Read a character from the UART.  Does not block.
+ *
+ * Returns the read character on success.  If the RX FIFO is currently empty
+ * (nothing to read), returns -1.
+ */
+static inline int uart_getc_nowait(int uart_num) {
+    if (FIELD2VAL(UART_STATUS_RXFIFO_COUNT, UART(uart_num).STATUS)) {
+        return UART(uart_num).FIFO;
+    }
+    return -1;
+}
+
+/* Write a character to the UART.  Blocks if necessary until there is space in
+ * the TX FIFO.
+ */
+static inline void uart_putc(int uart_num, char c) {
+    uart_txfifo_wait(uart_num, 1);
+    UART(uart_num).FIFO = c;
+}
+
+/* Write a character to the UART.  Does not block.
+ *
+ * Returns 0 on success.  If there is no space currently in the TX FIFO,
+ * returns -1.
+ */
+static inline int uart_putc_nowait(int uart_num, char c) {
+    if (FIELD2VAL(UART_STATUS_TXFIFO_COUNT, UART(uart_num).STATUS) < UART_FIFO_MAX) {
+        UART(uart_num).FIFO = c;
+        return 0;
+    }
+    return -1;
+}
+
+/* Clear (discard) all pending write data in the TX FIFO */
+static inline void uart_clear_txfifo(int uart_num) {
+    uint32_t conf = UART(uart_num).CONF0;
+    UART(uart_num).CONF0 = conf | UART_CONF0_TXFIFO_RESET;
+    UART(uart_num).CONF0 = conf & ~UART_CONF0_TXFIFO_RESET;
+}
+
+/* Clear (discard) all pending read data in the RX FIFO */
+static inline void uart_clear_rxfifo(int uart_num) {
+    uint32_t conf = UART(uart_num).CONF0;
+    UART(uart_num).CONF0 = conf | UART_CONF0_RXFIFO_RESET;
+    UART(uart_num).CONF0 = conf & ~UART_CONF0_RXFIFO_RESET;
+}
+
+/* Wait until all pending output in the UART's TX FIFO has been sent out the
+ * serial port. */
+static inline void uart_flush_txfifo(int uart_num) {
+    while (FIELD2VAL(UART_STATUS_TXFIFO_COUNT, UART(uart_num).STATUS) != 0) {}
+}
+
+/* Flush all pending input in the UART's RX FIFO
+ * (this is just another name for uart_clear_rxfifo)
+ */
+static inline void uart_flush_rxfifo(int uart_num) {
+    uart_clear_rxfifo(uart_num);
+}
+
+#endif /* _ESP_UART_H */

core/newlib_syscalls.c

@@ -9,6 +9,7 @@
 #include <sys/errno.h>
 #include <espressif/sdk_private.h>
 #include <common_macros.h>
+#include <esp/uart.h>
 #include <stdlib.h>
 
 IRAM caddr_t _sbrk_r (struct _reent *r, int incr)
@@ -32,37 +33,35 @@ IRAM caddr_t _sbrk_r (struct _reent *r, int incr)
     return (caddr_t) prev_heap_end;
 }
 
-/* syscall implementation for stdio write to UART
-
-   at the moment UART functionality is all still in the binary SDK
- */
+/* syscall implementation for stdio write to UART */
 long _write_r(struct _reent *r, int fd, const char *ptr, int len )
 {
     if(fd != r->_stdout->_file) {
         r->_errno = EBADF;
         return -1;
     }
-    for(int i = 0; i < len; i++)
-	sdk_os_putc(ptr[i]);
+    for(int i = 0; i < len; i++) {
+        uart_putc(0, ptr[i]);
+    }
     return len;
 }
 
-/* syscall implementation for stdio read from UART
-
-   at the moment UART functionality is all still in the binary SDK
- */
+/* syscall implementation for stdio read from UART */
 long _read_r( struct _reent *r, int fd, char *ptr, int len )
 {
+    int ch, i;
+
     if(fd != r->_stdin->_file) {
         r->_errno = EBADF;
         return -1;
     }
-    for(int i = 0; i < len; i++) {
-        char ch;
-        while (sdk_uart_rx_one_char(&ch)) ;
+    uart_rxfifo_wait(0, 1);
+    for(i = 0; i < len; i++) {
+        ch = uart_getc_nowait(0);
+        if (ch < 0) break;
         ptr[i] = ch;
     }
-    return len;
+    return i;
 }
 
 /* Stub syscall implementations follow, to allow compiling newlib functions that