retarget_usart.c

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/************************************************************************//**
 * \file    heivs/retarget_usart.c
 * \author  marc dot pignat at hevs dot ch
 *
 * \defgroup stdio_redir stdio redirection
 * \ingroup stdio_h
 * @{
 *
 * \brief stdio redirection for newlib
 *
 * Here is the low-level part of stdio (printf/scanf, puts, getc, ...) functions
 *
 ***************************************************************************/

#include "heivs/config.h"
#if defined(USE_STDIO_USART)

#include "heivs/retarget.h"
#include "heivs/stm32_usart.h"
#include "heivs/config.h"

#if !(USE_STDIO_USART < BSP_USART_BUS_COUNT)
#error USE_STDIO_USART should be < BSP_USART_BUS_COUNT
#endif

#include <stdio.h>

static const uint32_t use_stdio_nobuf = USE_STDIO_NOBUF;
static const uint32_t use_stdio_echo = USE_STDIO_ECHO;
static const uint32_t auto_crlf = USE_STDIO_AUTO_CR_BEFORE_LF;

/**
 * \brief Initialization
 *
 * Initializte the usart \#USE_STDIO_USART.
 *
 * \see USE_STDIO_USART
 */
void retarget_init()
{
    const struct heivs_bus_t *bus = &bus_usart[USE_STDIO_USART];
    #if USE_FREERTOS
    /**
     * stdio don't use the bus mutex.
     *
     * We want stdio to work even when the kernel has crashed
     */
    bus->var->mutex_ignore = 1;
    #endif
    bus_init(bus);

    if (use_stdio_nobuf)
    {
        setvbuf(stdout, NULL, _IONBF, 0);
        setvbuf(stderr, NULL, _IONBF, 0);
        setvbuf(stdin, NULL, _IONBF, 0);
    }
}

int _write(int fd, char *ptr, int len)
{
    (void)fd;
    const struct heivs_bus_t *bus = &bus_usart[USE_STDIO_USART];
    int i;
    bus_get(bus);

    if (auto_crlf)
    {
        for (i = 0 ; i < len ; i++)
        {
            char c = ptr[i];

            if (c == '\n')
            {
                char cr = '\r';
                bus_write(bus, 0, &cr, 1);
            }
            bus_write(bus, 0, &c, 1);
        }
    }
    else
    {
        bus_write(bus, 0, ptr, len);
    }

    bus_release(bus);

    return len;
}

int _read(int fd, char *ptr, int len)
{
    size_t l;
    const struct heivs_bus_t *bus = &bus_usart[USE_STDIO_USART];

    while (bus_get(bus) != NO_ERROR);

    do
    {
        status_e status;
        l = len;
        status = bus_read(bus, 0, ptr, len, &l);
        if (status != NO_ERROR)
        {
            bus_get(bus);
        }
    } while (l == 0);

    bus_release(bus);

    if (use_stdio_echo)
    {
        _write(fd, ptr, l);
    }

    return l;
}

#endif /* defined(USE_STDIO_USART) */

/************************************************************************//**
 * @}
 ***************************************************************************/