DMA

this is my verilog soure

module crc_peripheral ( reset, clk, chipselect, write,read,

writedata, address, readdata);

input reset;

input clk;

input chipselect;

input write;

input read;

input [31:0] writedata;

input address;

output reg [31:0] readdata;

reg [15:0] crc_result;

reg [15:0] crc_reg;

//////////

// Set result output

//assign readdata = {16'h0, crc_reg};

/////////

// Initialise or update CRC reg based on address line

wire [15:0] crc_reg_input = (address) ? crc_result : writedata[15:0];

//////////

// CRC needs big endian data but Nios is little endian

// Convert data here

wire [15:0] crc_word = {writedata[7:0], writedata[15:8]};

wire [15:0] next_crc_word = {writedata[23:16], writedata[31:24]};

/////////

// CRC calculation

integer i;

reg [15:0] crc_array[0:16];

always @ (crc_word, next_crc_word)

begin

crc_array[16] = crc_reg;

for (i=15; i>=0; i=i-1)

begin

crc_array [0] = crc_array [i+1][15] ^ crc_word;

crc_array [1] = crc_array [i+1][0];

crc_array [2] = crc_array [i+1][1];

crc_array [3] = crc_array [i+1][2];

crc_array [4] = crc_array [i+1][3];

crc_array [5] = crc_array [i+1][4] ^ crc_array [0];

crc_array [6] = crc_array [i+1][5];

crc_array [7] = crc_array [i+1][6];

crc_array [8] = crc_array [i+1][7];

crc_array [9] = crc_array [i+1][8];

crc_array [10] = crc_array [i+1][9];

crc_array [11] = crc_array [i+1][10];

crc_array [12] = crc_array [i+1][11] ^ crc_array [0];

crc_array [13] = crc_array [i+1][12];

crc_array [14] = crc_array [i+1][13];

crc_array [15] = crc_array [i+1][14];

end

crc_array[16] = crc_array[0];

for (i=15; i>=0; i=i-1)

begin

crc_array [0] = crc_array [i+1][15] ^ next_crc_word;

crc_array [1] = crc_array [i+1][0];

crc_array [2] = crc_array [i+1][1];

crc_array [3] = crc_array [i+1][2];

crc_array [4] = crc_array [i+1][3];

crc_array [5] = crc_array [i+1][4] ^ crc_array [0];

crc_array [6] = crc_array [i+1][5];

crc_array [7] = crc_array [i+1][6];

crc_array [8] = crc_array [i+1][7];

crc_array [9] = crc_array [i+1][8];

crc_array [10] = crc_array [i+1][9];

crc_array [11] = crc_array [i+1][10];

crc_array [12] = crc_array [i+1][11] ^ crc_array [0];

crc_array [13] = crc_array [i+1][12];

crc_array [14] = crc_array [i+1][13];

crc_array [15] = crc_array [i+1][14];

end

crc_result <= crc_array [0];

end

// CRC Register

always @ (posedge clk or posedge reset)

begin

if (reset)

crc_reg <= 0;

else

if (write && chipselect)

crc_reg <= crc_reg_input;

end

always @ (posedge clk or posedge reset)

begin

if (reset)

readdata <= 0;

else

if (read && chipselect)

readdata <= {16&#39;h0,crc_reg};

end

endmodule

this is my c program

volatile alt_u16 crcCompute(void)

{

alt_u16 word;

int value;

int pat[4]={0x00000003,0x00000004,0x00000005,0x00000006};

//alt_u8 pat[8]={0x00,0x00,0x00,0x03,0x00,0x00,0x00,0x04};

int mode;

//pat[0]=0x00000003;

printf("start crc\n");

IOWR(CRC_PERIPH_BASE,0,0x0000FFFF);

//value=IORD(CRC_PERIPH_BASE,0);

//printf("value= %x\n",value);

// value=IORD(CRC_PERIPH_BASE,1);

//printf("value= %x\n",value);

/*IOWR(SLAVE_REG_0_BASE,0,0x0000F0F0);

alt_dma_txchan_ioctl(tx,

ALT_DMA_TX_ONLY_ON,

(void*)(CRC_PERIPH_BASE+0x4 ));

alt_avalon_dma_send (tx,

(int)pat,

16 ,

//dma_done,

NULL,

NULL);*/

IOWR_ALTERA_AVALON_DMA_STATUS(AVALON_DMA_BASE, 0);

IOWR_ALTERA_AVALON_DMA_CONTROL(AVALON_DMA_BASE,0);

IOWR_ALTERA_AVALON_DMA_RADDRESS(AVALON_DMA_BASE, (int)pat);

IOWR_ALTERA_AVALON_DMA_WADDRESS(AVALON_DMA_BASE, (CRC_PERIPH_BASE+0x4));

IOWR_ALTERA_AVALON_DMA_LENGTH(AVALON_DMA_BASE, 4);

mode =

ALTERA_AVALON_DMA_CONTROL_WORD_MSK |

ALTERA_AVALON_DMA_CONTROL_GO_MSK |

ALTERA_AVALON_DMA_CONTROL_LEEN_MSK |

ALTERA_AVALON_DMA_CONTROL_WCON_MSK ;

IOWR_ALTERA_AVALON_DMA_CONTROL(AVALON_DMA_BASE,mode);

value=IORD(CRC_PERIPH_BASE,0);

printf("value= %x\n",value);

value=IORD(CRC_PERIPH_BASE,1);

printf("value= %x\n",value);

while (IORD_ALTERA_AVALON_DMA_STATUS (AVALON_DMA_BASE) &

ALTERA_AVALON_DMA_STATUS_BUSY_MSK);

printf("waiting crc\n");

word = (IORD((CRC_PERIPH_BASE),1));

printf("crc value0=%x\n",word);

word = (IORD((CRC_PERIPH_BASE+0x1),1));

printf("crc value1=%x\n",word);

word = (IORD((CRC_PERIPH_BASE+0x2),1));

printf("crc value2=%x\n",word);

word = (IORD((CRC_PERIPH_BASE+0x3),0));

printf("crc value3=%x\n",word);

word = (IORD((CRC_PERIPH_BASE+0x0),0));

printf("crc value4=%x\n",word);

word = (IORD((CRC_PERIPH_BASE+0x1),0));

printf("crc value5=%x\n",word);

word = (IORD((CRC_PERIPH_BASE+0x2),0));

printf("crc value6=%x\n",word);

word = (IORD((CRC_PERIPH_BASE+0x3),0));

printf("crc value7=%x\n",word);

word = (IORD((CRC_PERIPH_BASE),0));

printf("crc value00=%x\n",word);

return (word);

} /* crcCompute() */