Split networking from posix and qemu mps2 demos (#455)

Split networking from posix and qemu mps2 demos

FreeRTOS-Plus/Demo/FreeRTOS_Plus_TCP_Echo_Qemu_mps2/syscall.c

@@ -0,0 +1,130 @@
+/*
+ * FreeRTOS V202011.00
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ *
+ * 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.
+ *
+ * https://www.FreeRTOS.org
+ * https://github.com/FreeRTOS
+ *
+ */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <sys/types.h>
+
+typedef struct UART_t {
+    volatile uint32_t DATA;
+    volatile uint32_t STATE;
+    volatile uint32_t CTRL;
+    volatile uint32_t INTSTATUS;
+    volatile uint32_t BAUDDIV;
+} UART_t;
+
+#define UART0_ADDR ((UART_t *)(0x40004000))
+#define UART_DR(baseaddr) (*(unsigned int *)(baseaddr))
+
+#define UART_STATE_TXFULL (1 << 0)
+#define UART_CTRL_TX_EN (1 << 0)
+#define UART_CTRL_RX_EN (1 << 1)
+
+
+extern unsigned long _heap_bottom;
+extern unsigned long _heap_top;
+extern unsigned long g_ulBase;
+
+static void *heap_end = 0;
+
+/**
+ * @brief initializes the UART emulated hardware
+ */
+void uart_init()
+{
+    UART0_ADDR->BAUDDIV = 16;
+    UART0_ADDR->CTRL = UART_CTRL_TX_EN;
+}
+
+/**
+ * @brief not used anywhere in the code
+ * @todo  implement if necessary
+ *
+ */
+int _fstat(int file)
+{
+    return 0;
+}
+
+/**
+ * @brief not used anywhere in the code
+ * @todo  implement if necessary
+ *
+ */
+int _read(int file, char *buf, int len)
+{
+     return -1;
+}
+
+/**
+ * @brief  Write bytes to the UART channel to be displayed on the command line
+ *         with qemu
+ * @param [in] file  ignored
+ * @param [in] buf   buffer to send
+ * @param [in] len   length of the buffer
+ * @returns the number of bytes written
+ */
+int _write(int file, char *buf, int len)
+{
+    int todo;
+
+    for (todo = 0; todo < len; todo++){
+        UART_DR(UART0_ADDR) = *buf++;
+    }
+    return len;
+}
+
+/**
+ * @brief function called by malloc and friends to reserve memory on the heap
+ * @param [in] incr the amount of bytes to increase or decrease
+ * @returns the previous top of the heap
+ * @note uses a global variable <b>heap_end</b> to keep track of the previous top
+ */
+void* _sbrk(int incr)
+{
+    char *prev_heap_end;
+
+    if (heap_end == 0)
+    {
+        heap_end = (void*) &_heap_bottom;
+    }
+
+    prev_heap_end = heap_end;
+
+    if ((heap_end + incr) > (void*)&_heap_top)
+    {
+        return (void*)-1;
+    }
+
+    heap_end += incr;
+
+    return prev_heap_end;
+}
+
+#ifdef __cplusplus
+}
+#endif