obsw/bsp_z7/hardware/interfaces.c

#include <hardware/interfaces.h>
#include <xparameters_ps.h>
#include <xuartps.h>
#include <stdint.h>

#include "interface_access.h"
#include "interface_fds.h"

int compare_string_chars(const char *c_string, const char *chars,
                         size_t chars_len) {
  for(int i = 0; i < chars_len; i++) {
    if (c_string[i] == 0) {
      return 0;
    }
    if (c_string[i] != chars[i]) {;
      return 0;
    }
  }
  return 1;
}

int hw_device_open(const char *path, size_t path_len) {
  if (compare_string_chars("uart0", path, path_len) == 1) {
    return UART_0;
  }
  if (compare_string_chars("uart1", path, path_len) == 1) {
    return UART_1;
  }

  return -1;
}

ssize_t hw_device_transfer(int fd, void *sendbuffer, void *receivebuffer,
                           size_t buffer_len) {
  return -1;
}

// we could implement interrupt based nonblocking sending using a queue
// like we do receiving (where we need it for the small hw buffer)
// but in the end, we do not want too many interrupts, so we do it blocking
void send_uart(uint32_t BaseAddress, const char *data, int data_len) {
  int todo;
  for (todo = 0; todo < data_len; todo++) {
    XUartPs_SendByte(BaseAddress, *data++);
  }
}

int hw_interface_write(int fd, const char *ptr, int len) {
  enum InterfaceFileDescriptors fd_enum = fd;
  switch (fd) {
  case UART_0:
    send_uart(XPS_UART0_BASEADDR, ptr, len);
    return len;
  case UART_1:
    send_uart(XPS_UART1_BASEADDR, ptr, len);
    return len;
  }
  return -1;
}

int hw_interface_read(int fd, char *ptr, int len) {
  enum InterfaceFileDescriptors fd_enum = fd;
  switch (fd) {
  case UART_0:
    return 0;
  case UART_1:
    return 0;
  }
  return -1;
}