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/*
* FreeRTOS V202111.00
* 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
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