Not able to send ethernet frame from FPGA to windows PC

#include <altera_avalon_sgdma.h>

# include <altera_avalon_sgdma_descriptor.h>

# include <altera_avalon_sgdma_regs.h>

# include "sys/alt_stdio.h"

# include "sys/alt_irq.h"

# include <unistd.h>

// Function Prototypes

void rx_ethernet_isr (void *context);

//void tx_ethernet_isr (void *context);

//void tx_ethernet_isr (void *context);

// Global Variables

unsigned int i=0;

// Create a transmit frame char=1 byte

unsigned char tx_frame[1518] = { 0 };

// Create a receive frame

unsigned char rx_frame[1518] = { 0 };

// Create sgdma transmit and receive devices

alt_sgdma_dev * sgdma_tx_dev;

alt_sgdma_dev * sgdma_rx_dev;

// Allocate descriptors in the descriptor_memory (onchip memory)

alt_sgdma_descriptor tx_descriptor __attribute__ (( section ( ".descriptor_memory" )));

alt_sgdma_descriptor tx_descriptor_end __attribute__ (( section ( ".descriptor_memory" )));

alt_sgdma_descriptor rx_descriptor __attribute__ (( section ( ".descriptor_memory" )));

alt_sgdma_descriptor rx_descriptor_end __attribute__ (( section ( ".descriptor_memory" )));

/********************************************************************************

* This program demonstrates use of the Ethernet in the DE2-115 board.

*

* It performs the following:

* 1. Records input text and transmits the text via Ethernet after Enter is

* pressed

* 2. Displays text received via Ethernet frame on the JTAG UART

********************************************************************************/

int main(void)

{

// Open the sgdma transmit device

sgdma_tx_dev = alt_avalon_sgdma_open ("/dev/sgdma_tx");

if (sgdma_tx_dev == NULL) {

alt_printf ("Error: could not open scatter-gather dma transmit device\n");

return -1;

} else alt_printf ("Opened scatter-gather dma transmit device\n");

// Open the sgdma receive device

sgdma_rx_dev = alt_avalon_sgdma_open ("/dev/sgdma_rx");

if (sgdma_rx_dev == NULL) {

alt_printf ("Error: could not open scatter-gather dma receive device\n");

return -1;

} else alt_printf ("Opened scatter-gather dma receive device\n");

// Set interrupts for the sgdma receive device

alt_avalon_sgdma_register_callback( sgdma_rx_dev, (alt_avalon_sgdma_callback) rx_ethernet_isr, 0x00000014, NULL );

// Create sgdma receive descriptor

alt_avalon_sgdma_construct_stream_to_mem_desc( &rx_descriptor, &rx_descriptor_end, (alt_u32 *)rx_frame, 0, 0 );

// Set up non-blocking transfer of sgdma receive descriptor

alt_avalon_sgdma_do_async_transfer( sgdma_rx_dev, &rx_descriptor );

// Triple-speed Ethernet MegaCore base address

volatile int * tse = (int *) 0x00102000;

// Initialize the MAC address

//*(tse + 3) = 0x116E6001;

//*(tse + 4) = 0x00000F02;

// Specify the addresses of the PHY devices to be accessed through MDIO interface

*(tse + 0x0F) = 0x10;

*(tse + 0x10) = 0x11;

// Write to register 20 of the PHY chip for Ethernet port 0 to set up line loopback

*(tse + 0x94) = 0x4000;

// Write to register 16 of the PHY chip for Ethernet port 1 to enable automatic crossover for all modes("| = OR")

*(tse + 0xB0) = *(tse + 0xB0) | 0x0060;

// Write to register 20 of the PHY chip for Ethernet port 2 to set up delay for input/output clk

*(tse + 0xB4) = *(tse + 0xB4) | 0x0082;

// Software reset the second PHY chip and wait

*(tse + 0xA0) = *(tse + 0xA0) | 0x8000;

while ( *(tse + 0xA0) & 0x8000 )

;

// Enable read and write transfers, gigabit Ethernet operation, and CRC forwarding

*(tse + 2) = *(tse + 2) | 0x000000CB;

alt_avalon_sgdma_construct_mem_to_stream_desc( &tx_descriptor, &tx_descriptor_end, (alt_u32 *)tx_frame, 60, 0, 1, 1, 0 );

// Set up non-blocking transfer of sgdma transmit descriptor

alt_avalon_sgdma_do_async_transfer( sgdma_tx_dev, &tx_descriptor );

// Wait until transmit descriptor transfer is complete

while (alt_avalon_sgdma_check_descriptor_status(&tx_descriptor) != 0)

;

return 0;

}

/****************************************************************************************

* Subroutine to read incoming Ethernet frames

****************************************************************************************/

void rx_ethernet_isr (void *context)

{

// Wait until receive descriptor transfer is complete

while (alt_avalon_sgdma_check_descriptor_status(&rx_descriptor) != 0);

// Create new receive sgdma descriptor

alt_avalon_sgdma_construct_stream_to_mem_desc( &rx_descriptor, &rx_descriptor_end, (alt_u32 *)rx_frame, 0, 0 );

// Set up non-blocking transfer of sgdma receive descriptor

alt_avalon_sgdma_do_async_transfer( sgdma_rx_dev, &rx_descriptor );

for(i=0;i<=1518;i++)

tx_frame=rx_frame;

for (i=0;i<=25;i++)

alt_printf("%x",rx_frame[i]);

alt_printf("\n");

alt_printf("%x",rx_frame[25]);

alt_printf("\n");

}

This is the complete code