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/*

 * UART interrupt test

 *

 * Tests UART and interrupt routines servicing them.

 *

 * Relies on testbench having uart0's lines in loopback (rx = tx)

 *

 * Julius Baxter, julius.baxter@orsoc.se

 *

*/

#include "cpu-utils.h"

#include "spr-defs.h"

#include "board.h"

#include "uart.h"

#include "int.h"

#include "orpsoc-defines.h"

#ifndef UART0

# error

# error UART0 missing and is required for UART interrupt (loopback) test

# error

#endif

struct uart_tx_ctrl

{

  char *bufptr;

  int busy;

};

volatile struct uart_tx_ctrl uart0_tx_ctrl;

void uart_int_handler(void* corenum);

void uart_int_handler(void* corenum)

{

  int core = *((int*)corenum);

  if (core)report(core);

  char iir = uart_get_iir(core);

  if ( (iir & UART_IIR_RLSI)  == UART_IIR_RLSI)

    uart_get_lsr(core); // Should clear this interrupt

  else if ( (iir & UART_IIR_RDI) == UART_IIR_RDI )

    {

      // Was potentially also a timeout. Do we care?

      // Data received. Pull all from the FIFO buffer, here we just report it

      // and throw it away

      char rxchar;

      while (uart_check_for_char(core))

        {

          rxchar = uart_getc(core);

          report(0xff & rxchar);

          if (rxchar == 0x2a) // Exit simulation when RX char is '*'

            exit(0x8000000d);

        }

    }

  else if ( (iir & UART_IIR_THRI) ==  UART_IIR_THRI)

    {

      // Only trigered if we've set something to be transmitted

      // and enabled the interrupt.

      // Put next thing to be transmitted into buffer, check if it's

      // the last, if so, disable interrupts.

      if (uart0_tx_ctrl.bufptr[0] == 0) // EOL, disable interrupt after this char

        {

          uart_txint_disable(core);

          uart0_tx_ctrl.busy = 0;

        }

      else // Transmit this byte

        {

          uart_putc_noblock(core, uart0_tx_ctrl.bufptr[0]);

          uart0_tx_ctrl.bufptr++;

        }

    }

  else if ( (iir & UART_IIR_MSI) == UART_IIR_MSI )

    {

      // Just read the modem status register to clear this

      uart_get_msr(core);

    }

}

void uart0_tx_buffer(char* buf)

{

  while (uart0_tx_ctrl.busy); // Wait until we can transmit more

  uart0_tx_ctrl.bufptr = buf;

  uart0_tx_ctrl.busy = 1;

  uart_txint_enable(0);

}

int main()

{

  int uart0_core = 0;

  int uart1_core = 1;

  uart0_tx_ctrl.busy = 0;

  /* Set up interrupt handler */

  int_init();

  /* Install UART core 0 interrupt handler */

  int_add(UART0_IRQ, uart_int_handler,(void*) &uart0_core);

  /* Install UART core 1 interrupt handler */

  //int_add(UART1_IRQ, uart_int_handler,(void*) &uart1_core);

  /* Enable interrupts in supervisor register */

  mtspr (SPR_SR, mfspr (SPR_SR) | SPR_SR_IEE);

  uart_init(uart0_core);

  //uart_init(uart1_core);

  //uart_rxint_enable(uart1_core);

  uart_rxint_enable(uart0_core);

  char* teststring = "\n\tHello world from UART 0\n\0";

  uart0_tx_buffer(teststring);

  // Do other things while we transmit

  float f1, f2, f3; int i;

  f1 = 0.2382; f2 = 4342.65; f3=0;

  for(i=0;i<32;i++) f3 += f1*f3 + f2;

  report(f3);

  report(0x4aaaaa1f);

  char* done_calculating = "\tDone with the number crunching!\n\0";

  uart0_tx_buffer(done_calculating);

  // Character '*', which will be received in the interrupt handler and cause

  // the simulation to exit.

  char* finish = "*\n\0";

  uart0_tx_buffer(finish);

  while(1); // will exit in the rx interrupt routine

}