hw tune:

[proxmark3-svn] / armsrc / fpgaloader.c

diff --git a/armsrc/fpgaloader.c b/armsrc/fpgaloader.c
index be0d87d61bc1633cb431690d3a3c3383ffe904d6..c0b04f3cc99c4aa09526dd5a57f71fbec827b4cb 100644 (file)
--- a/armsrc/fpgaloader.c
+++ b/armsrc/fpgaloader.c
@@ -26,13 +26,15 @@ extern void Dbprintf(const char *fmt, ...);
 static int downloaded_bitstream = FPGA_BITSTREAM_ERR;
 
 // this is where the bitstreams are located in memory:
 static int downloaded_bitstream = FPGA_BITSTREAM_ERR;
 
 // this is where the bitstreams are located in memory:

-extern uint8_t _binary_fpga_lf_bit_start, _binary_fpga_lf_bit_end;
-extern uint8_t _binary_fpga_hf_bit_start, _binary_fpga_hf_bit_end;
+extern uint8_t _binary_obj_fpga_all_bit_z_start, _binary_obj_fpga_all_bit_z_end;
+

 static uint8_t *fpga_image_ptr = NULL;
 static uint8_t *fpga_image_ptr = NULL;

+static uint32_t uncompressed_bytes_cnt;

 
 static const uint8_t _bitparse_fixed_header[] = {0x00, 0x09, 0x0f, 0xf0, 0x0f, 0xf0, 0x0f, 0xf0, 0x0f, 0xf0, 0x00, 0x00, 0x01};
 #define FPGA_BITSTREAM_FIXED_HEADER_SIZE       sizeof(_bitparse_fixed_header)
 
 static const uint8_t _bitparse_fixed_header[] = {0x00, 0x09, 0x0f, 0xf0, 0x0f, 0xf0, 0x0f, 0xf0, 0x0f, 0xf0, 0x00, 0x00, 0x01};
 #define FPGA_BITSTREAM_FIXED_HEADER_SIZE       sizeof(_bitparse_fixed_header)

-#define OUTPUT_BUFFER_LEN 80
+#define OUTPUT_BUFFER_LEN              80
+#define FPGA_INTERLEAVE_SIZE   288

 
 //-----------------------------------------------------------------------------
 // Set up the Serial Peripheral Interface as master
 
 //-----------------------------------------------------------------------------
 // Set up the Serial Peripheral Interface as master


@@ -156,9 +158,7 @@ void FpgaSetupSsc(void)
 //-----------------------------------------------------------------------------
 bool FpgaSetupSscDma(uint8_t *buf, int len)
 {
 //-----------------------------------------------------------------------------
 bool FpgaSetupSscDma(uint8_t *buf, int len)
 {

-       if (buf == NULL) {
-        return false;
-    }
+       if (buf == NULL) return false;

 
        AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;        // Disable DMA Transfer
        AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) buf;           // transfer to this memory address
 
        AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;        // Disable DMA Transfer
        AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) buf;           // transfer to this memory address


@@ -166,75 +166,86 @@ bool FpgaSetupSscDma(uint8_t *buf, int len)
        AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) buf;          // next transfer to same memory address
        AT91C_BASE_PDC_SSC->PDC_RNCR = len;                                     // ... with same number of bytes
        AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTEN;         // go!
        AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) buf;          // next transfer to same memory address
        AT91C_BASE_PDC_SSC->PDC_RNCR = len;                                     // ... with same number of bytes
        AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTEN;         // go!

-    
-    return true;
+
+       return true;

 }
 
 
 }
 
 

-static int get_from_fpga_stream(z_streamp compressed_fpga_stream, uint8_t *output_buffer)
+//----------------------------------------------------------------------------
+// Uncompress (inflate) the FPGA data. Returns one decompressed byte with
+// each call. 
+//----------------------------------------------------------------------------
+static int get_from_fpga_combined_stream(z_streamp compressed_fpga_stream, uint8_t *output_buffer)

 {
        if (fpga_image_ptr == compressed_fpga_stream->next_out) {       // need more data
                compressed_fpga_stream->next_out = output_buffer;
                compressed_fpga_stream->avail_out = OUTPUT_BUFFER_LEN;
                fpga_image_ptr = output_buffer;
                int res = inflate(compressed_fpga_stream, Z_SYNC_FLUSH);
 {
        if (fpga_image_ptr == compressed_fpga_stream->next_out) {       // need more data
                compressed_fpga_stream->next_out = output_buffer;
                compressed_fpga_stream->avail_out = OUTPUT_BUFFER_LEN;
                fpga_image_ptr = output_buffer;
                int res = inflate(compressed_fpga_stream, Z_SYNC_FLUSH);

-               if (res != Z_OK) {
+               if (res != Z_OK)

                        Dbprintf("inflate returned: %d, %s", res, compressed_fpga_stream->msg);
                        Dbprintf("inflate returned: %d, %s", res, compressed_fpga_stream->msg);

-               }
-               if (res < 0) {
+
+               if (res < 0)

                        return res;
                        return res;

-               }

        }
 
        }
 

+       uncompressed_bytes_cnt++;
+       

        return *fpga_image_ptr++;
 }
 
        return *fpga_image_ptr++;
 }
 

+//----------------------------------------------------------------------------
+// Undo the interleaving of several FPGA config files. FPGA config files
+// are combined into one big file:
+// 288 bytes from FPGA file 1, followed by 288 bytes from FGPA file 2, etc.
+//----------------------------------------------------------------------------
+static int get_from_fpga_stream(int bitstream_version, z_streamp compressed_fpga_stream, uint8_t *output_buffer)
+{
+       while((uncompressed_bytes_cnt / FPGA_INTERLEAVE_SIZE) % FPGA_BITSTREAM_MAX != (bitstream_version - 1)) {
+               // skip undesired data belonging to other bitstream_versions
+               get_from_fpga_combined_stream(compressed_fpga_stream, output_buffer);
+       }
+
+       return get_from_fpga_combined_stream(compressed_fpga_stream, output_buffer);
+       
+}
+

 
 static voidpf fpga_inflate_malloc(voidpf opaque, uInt items, uInt size)
 {
 
 static voidpf fpga_inflate_malloc(voidpf opaque, uInt items, uInt size)
 {

-       Dbprintf("zlib requested %d bytes", items*size);

        return BigBuf_malloc(items*size);
 }
 
 
 static void fpga_inflate_free(voidpf opaque, voidpf address)
 {
        return BigBuf_malloc(items*size);
 }
 
 
 static void fpga_inflate_free(voidpf opaque, voidpf address)
 {

-       Dbprintf("zlib frees memory");
-       BigBuf_free_keep_EM();
+       BigBuf_free(); BigBuf_Clear_ext(false);

 }
 
 
 }
 
 

+//----------------------------------------------------------------------------
+// Initialize decompression of the respective (HF or LF) FPGA stream 
+//----------------------------------------------------------------------------

 static bool reset_fpga_stream(int bitstream_version, z_streamp compressed_fpga_stream, uint8_t *output_buffer)
 {
        uint8_t header[FPGA_BITSTREAM_FIXED_HEADER_SIZE];
 static bool reset_fpga_stream(int bitstream_version, z_streamp compressed_fpga_stream, uint8_t *output_buffer)
 {
        uint8_t header[FPGA_BITSTREAM_FIXED_HEADER_SIZE];

-       uint8_t *fpga_image_start;
-       uint32_t fpga_image_size;

        
        

-       if (bitstream_version == FPGA_BITSTREAM_LF) {
-               fpga_image_start = &_binary_fpga_lf_bit_start;
-               fpga_image_size = (uint32_t)&_binary_fpga_lf_bit_end - (uint32_t)&_binary_fpga_lf_bit_start;
-       } else if (bitstream_version == FPGA_BITSTREAM_HF) {
-               fpga_image_start = &_binary_fpga_hf_bit_start;
-               fpga_image_size = (uint32_t)&_binary_fpga_hf_bit_end - (uint32_t)&_binary_fpga_hf_bit_start;
-       } else {
-               return false;
-       }       
-
+       uncompressed_bytes_cnt = 0;
+       

        // initialize z_stream structure for inflate:
        // initialize z_stream structure for inflate:

-       compressed_fpga_stream->next_in = fpga_image_start;
-       compressed_fpga_stream->avail_in = fpga_image_size;
+       compressed_fpga_stream->next_in = &_binary_obj_fpga_all_bit_z_start;
+       compressed_fpga_stream->avail_in = &_binary_obj_fpga_all_bit_z_start - &_binary_obj_fpga_all_bit_z_end;

        compressed_fpga_stream->next_out = output_buffer;
        compressed_fpga_stream->avail_out = OUTPUT_BUFFER_LEN;
        compressed_fpga_stream->zalloc = &fpga_inflate_malloc;
        compressed_fpga_stream->zfree = &fpga_inflate_free;
 
        compressed_fpga_stream->next_out = output_buffer;
        compressed_fpga_stream->avail_out = OUTPUT_BUFFER_LEN;
        compressed_fpga_stream->zalloc = &fpga_inflate_malloc;
        compressed_fpga_stream->zfree = &fpga_inflate_free;
 

-       // initialize inflate with WindowBits=15 and to automatically detect header:
-       inflateInit2(compressed_fpga_stream, 15+32);
+       inflateInit2(compressed_fpga_stream, 0);

 
        fpga_image_ptr = output_buffer;
 
        for (uint16_t i = 0; i < FPGA_BITSTREAM_FIXED_HEADER_SIZE; i++) {
 
        fpga_image_ptr = output_buffer;
 
        for (uint16_t i = 0; i < FPGA_BITSTREAM_FIXED_HEADER_SIZE; i++) {

-               header[i] = get_from_fpga_stream(compressed_fpga_stream, output_buffer);
+               header[i] = get_from_fpga_stream(bitstream_version, compressed_fpga_stream, output_buffer);

        }
        
        // Check for a valid .bit file (starts with _bitparse_fixed_header)
        }
        
        // Check for a valid .bit file (starts with _bitparse_fixed_header)


@@ -260,10 +271,10 @@ static void DownloadFPGA_byte(unsigned char w)
 }
 
 // Download the fpga image starting at current stream position with length FpgaImageLen bytes
 }
 
 // Download the fpga image starting at current stream position with length FpgaImageLen bytes

-static void DownloadFPGA(int FpgaImageLen, z_streamp compressed_fpga_stream, uint8_t *output_buffer)
+static void DownloadFPGA(int bitstream_version, int FpgaImageLen, z_streamp compressed_fpga_stream, uint8_t *output_buffer)

 {
 
 {
 

-       Dbprintf("DownloadFPGA(len: %d)", FpgaImageLen);
+       //Dbprintf("DownloadFPGA(len: %d)", FpgaImageLen);

        
        int i=0;
 
        
        int i=0;
 


@@ -317,7 +328,7 @@ static void DownloadFPGA(int FpgaImageLen, z_streamp compressed_fpga_stream, uin
        }
 
        for(i = 0; i < FpgaImageLen; i++) {
        }
 
        for(i = 0; i < FpgaImageLen; i++) {

-               int b = get_from_fpga_stream(compressed_fpga_stream, output_buffer);
+               int b = get_from_fpga_stream(bitstream_version, compressed_fpga_stream, output_buffer);

                if (b < 0) {
                        Dbprintf("Error %d during FpgaDownload", b);
                        break;
                if (b < 0) {
                        Dbprintf("Error %d during FpgaDownload", b);
                        break;


@@ -325,8 +336,6 @@ static void DownloadFPGA(int FpgaImageLen, z_streamp compressed_fpga_stream, uin
                DownloadFPGA_byte(b);
        }
        
                DownloadFPGA_byte(b);
        }
        

-       Dbprintf("%d bytes loaded into FPGA", i);
-       

        // continue to clock FPGA until ready signal goes high
        i=100000;
        while ( (i--) && ( !(AT91C_BASE_PIOA->PIO_PDSR & GPIO_FPGA_DONE ) ) ) {
        // continue to clock FPGA until ready signal goes high
        i=100000;
        while ( (i--) && ( !(AT91C_BASE_PIOA->PIO_PDSR & GPIO_FPGA_DONE ) ) ) {


@@ -349,13 +358,13 @@ static void DownloadFPGA(int FpgaImageLen, z_streamp compressed_fpga_stream, uin
  * (big endian), <length> bytes content. Except for section 'e' which has 4 bytes
  * length.
  */
  * (big endian), <length> bytes content. Except for section 'e' which has 4 bytes
  * length.
  */

-static int bitparse_find_section(char section_name, unsigned int *section_length, z_streamp compressed_fpga_stream, uint8_t *output_buffer)
+static int bitparse_find_section(int bitstream_version, char section_name, unsigned int *section_length, z_streamp compressed_fpga_stream, uint8_t *output_buffer)

 {
        int result = 0;
        #define MAX_FPGA_BIT_STREAM_HEADER_SEARCH 100  // maximum number of bytes to search for the requested section
        uint16_t numbytes = 0;
        while(numbytes < MAX_FPGA_BIT_STREAM_HEADER_SEARCH) {
 {
        int result = 0;
        #define MAX_FPGA_BIT_STREAM_HEADER_SEARCH 100  // maximum number of bytes to search for the requested section
        uint16_t numbytes = 0;
        while(numbytes < MAX_FPGA_BIT_STREAM_HEADER_SEARCH) {

-               char current_name = get_from_fpga_stream(compressed_fpga_stream, output_buffer);
+               char current_name = get_from_fpga_stream(bitstream_version, compressed_fpga_stream, output_buffer);

                numbytes++;
                unsigned int current_length = 0;
                if(current_name < 'a' || current_name > 'e') {
                numbytes++;
                unsigned int current_length = 0;
                if(current_name < 'a' || current_name > 'e') {


@@ -366,12 +375,12 @@ static int bitparse_find_section(char section_name, unsigned int *section_length
                switch(current_name) {
                case 'e':
                        /* Four byte length field */
                switch(current_name) {
                case 'e':
                        /* Four byte length field */

-                       current_length += get_from_fpga_stream(compressed_fpga_stream, output_buffer) << 24;
-                       current_length += get_from_fpga_stream(compressed_fpga_stream, output_buffer) << 16;
+                       current_length += get_from_fpga_stream(bitstream_version, compressed_fpga_stream, output_buffer) << 24;
+                       current_length += get_from_fpga_stream(bitstream_version, compressed_fpga_stream, output_buffer) << 16;

                        numbytes += 2;
                default: /* Fall through, two byte length field */
                        numbytes += 2;
                default: /* Fall through, two byte length field */

-                       current_length += get_from_fpga_stream(compressed_fpga_stream, output_buffer) << 8;
-                       current_length += get_from_fpga_stream(compressed_fpga_stream, output_buffer) << 0;
+                       current_length += get_from_fpga_stream(bitstream_version, compressed_fpga_stream, output_buffer) << 8;
+                       current_length += get_from_fpga_stream(bitstream_version, compressed_fpga_stream, output_buffer) << 0;

                        numbytes += 2;
                }
 
                        numbytes += 2;
                }
 


@@ -388,7 +397,7 @@ static int bitparse_find_section(char section_name, unsigned int *section_length
                }
 
                for (uint16_t i = 0; i < current_length && numbytes < MAX_FPGA_BIT_STREAM_HEADER_SEARCH; i++) {
                }
 
                for (uint16_t i = 0; i < current_length && numbytes < MAX_FPGA_BIT_STREAM_HEADER_SEARCH; i++) {

-                       get_from_fpga_stream(compressed_fpga_stream, output_buffer);
+                       get_from_fpga_stream(bitstream_version, compressed_fpga_stream, output_buffer);

                        numbytes++;
                }
        }
                        numbytes++;
                }
        }


@@ -397,50 +406,66 @@ static int bitparse_find_section(char section_name, unsigned int *section_length
 }
 
 
 }
 
 

-//-----------------------------------------------------------------------------
-// Find out which FPGA image format is stored in flash, then call DownloadFPGA
-// with the right parameters to download the image
-//-----------------------------------------------------------------------------
+//----------------------------------------------------------------------------
+// Check which FPGA image is currently loaded (if any). If necessary 
+// decompress and load the correct (HF or LF) image to the FPGA
+//----------------------------------------------------------------------------

 void FpgaDownloadAndGo(int bitstream_version)
 {
        z_stream compressed_fpga_stream;
 void FpgaDownloadAndGo(int bitstream_version)
 {
        z_stream compressed_fpga_stream;

-       uint8_t output_buffer[OUTPUT_BUFFER_LEN];
+       uint8_t output_buffer[OUTPUT_BUFFER_LEN] = {0x00};

        
        // check whether or not the bitstream is already loaded
        if (downloaded_bitstream == bitstream_version)
                return;
 
        
        // check whether or not the bitstream is already loaded
        if (downloaded_bitstream == bitstream_version)
                return;
 

+       // make sure that we have enough memory to decompress
+       BigBuf_free(); BigBuf_Clear_ext(false); 
+       

        if (!reset_fpga_stream(bitstream_version, &compressed_fpga_stream, output_buffer)) {
                return;
        }
 
        unsigned int bitstream_length;
        if (!reset_fpga_stream(bitstream_version, &compressed_fpga_stream, output_buffer)) {
                return;
        }
 
        unsigned int bitstream_length;

-       if(bitparse_find_section('e', &bitstream_length, &compressed_fpga_stream, output_buffer)) {
-               DownloadFPGA(bitstream_length, &compressed_fpga_stream, output_buffer);
+       if(bitparse_find_section(bitstream_version, 'e', &bitstream_length, &compressed_fpga_stream, output_buffer)) {
+               DownloadFPGA(bitstream_version, bitstream_length, &compressed_fpga_stream, output_buffer);

                downloaded_bitstream = bitstream_version;
        }
 
        inflateEnd(&compressed_fpga_stream);
                downloaded_bitstream = bitstream_version;
        }
 
        inflateEnd(&compressed_fpga_stream);

-               
+       
+       // turn off antenna
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+       
+       // free eventually allocated BigBuf memory
+       BigBuf_free(); BigBuf_Clear_ext(false); 

 }      
 
 
 }      
 
 

+//-----------------------------------------------------------------------------
+// Gather version information from FPGA image. Needs to decompress the begin 
+// of the respective (HF or LF) image.
+// Note: decompression makes use of (i.e. overwrites) BigBuf[]. It is therefore
+// advisable to call this only once and store the results for later use.
+//-----------------------------------------------------------------------------

 void FpgaGatherVersion(int bitstream_version, char *dst, int len)
 {
        unsigned int fpga_info_len;
 void FpgaGatherVersion(int bitstream_version, char *dst, int len)
 {
        unsigned int fpga_info_len;

-       char tempstr[40];
+       char tempstr[40] = {0x00};

        z_stream compressed_fpga_stream;
        z_stream compressed_fpga_stream;

-       uint8_t output_buffer[OUTPUT_BUFFER_LEN];
+       uint8_t output_buffer[OUTPUT_BUFFER_LEN] = {0x00};

        
        dst[0] = '\0';
 
        
        dst[0] = '\0';
 

-       if (!reset_fpga_stream(bitstream_version, &compressed_fpga_stream, output_buffer)) {
+       // ensure that we can allocate enough memory for decompression:
+       BigBuf_free(); BigBuf_Clear_ext(false);
+
+       if (!reset_fpga_stream(bitstream_version, &compressed_fpga_stream, output_buffer))

                return;
                return;

-       }

 
 

-       if(bitparse_find_section('a', &fpga_info_len, &compressed_fpga_stream, output_buffer)) {
+       if(bitparse_find_section(bitstream_version, 'a', &fpga_info_len, &compressed_fpga_stream, output_buffer)) {

                for (uint16_t i = 0; i < fpga_info_len; i++) {
                for (uint16_t i = 0; i < fpga_info_len; i++) {

-                       char c = (char)get_from_fpga_stream(&compressed_fpga_stream, output_buffer);
+                       char c = (char)get_from_fpga_stream(bitstream_version, &compressed_fpga_stream, output_buffer);

                        if (i < sizeof(tempstr)) {
                                tempstr[i] = c;
                        }
                        if (i < sizeof(tempstr)) {
                                tempstr[i] = c;
                        }


@@ -451,30 +476,30 @@ void FpgaGatherVersion(int bitstream_version, char *dst, int len)
                        strncat(dst, "HF ", len-1);
        }
        strncat(dst, "FPGA image built", len-1);
                        strncat(dst, "HF ", len-1);
        }
        strncat(dst, "FPGA image built", len-1);

-       if(bitparse_find_section('b', &fpga_info_len, &compressed_fpga_stream, output_buffer)) {
+       if(bitparse_find_section(bitstream_version, 'b', &fpga_info_len, &compressed_fpga_stream, output_buffer)) {

                strncat(dst, " for ", len-1);
                for (uint16_t i = 0; i < fpga_info_len; i++) {
                strncat(dst, " for ", len-1);
                for (uint16_t i = 0; i < fpga_info_len; i++) {

-                       char c = (char)get_from_fpga_stream(&compressed_fpga_stream, output_buffer);
+                       char c = (char)get_from_fpga_stream(bitstream_version, &compressed_fpga_stream, output_buffer);

                        if (i < sizeof(tempstr)) {
                                tempstr[i] = c;
                        }
                }
                strncat(dst, tempstr, len-1);
        }
                        if (i < sizeof(tempstr)) {
                                tempstr[i] = c;
                        }
                }
                strncat(dst, tempstr, len-1);
        }

-       if(bitparse_find_section('c', &fpga_info_len, &compressed_fpga_stream, output_buffer)) {
+       if(bitparse_find_section(bitstream_version, 'c', &fpga_info_len, &compressed_fpga_stream, output_buffer)) {

                strncat(dst, " on ", len-1);
                for (uint16_t i = 0; i < fpga_info_len; i++) {
                strncat(dst, " on ", len-1);
                for (uint16_t i = 0; i < fpga_info_len; i++) {

-                       char c = (char)get_from_fpga_stream(&compressed_fpga_stream, output_buffer);
+                       char c = (char)get_from_fpga_stream(bitstream_version, &compressed_fpga_stream, output_buffer);

                        if (i < sizeof(tempstr)) {
                                tempstr[i] = c;
                        }
                }
                strncat(dst, tempstr, len-1);
        }
                        if (i < sizeof(tempstr)) {
                                tempstr[i] = c;
                        }
                }
                strncat(dst, tempstr, len-1);
        }

-       if(bitparse_find_section('d', &fpga_info_len, &compressed_fpga_stream, output_buffer)) {
+       if(bitparse_find_section(bitstream_version, 'd', &fpga_info_len, &compressed_fpga_stream, output_buffer)) {

                strncat(dst, " at ", len-1);
                for (uint16_t i = 0; i < fpga_info_len; i++) {
                strncat(dst, " at ", len-1);
                for (uint16_t i = 0; i < fpga_info_len; i++) {

-                       char c = (char)get_from_fpga_stream(&compressed_fpga_stream, output_buffer);
+                       char c = (char)get_from_fpga_stream(bitstream_version, &compressed_fpga_stream, output_buffer);

                        if (i < sizeof(tempstr)) {
                                tempstr[i] = c;
                        }
                        if (i < sizeof(tempstr)) {
                                tempstr[i] = c;
                        }


@@ -482,8 +507,9 @@ void FpgaGatherVersion(int bitstream_version, char *dst, int len)
                strncat(dst, tempstr, len-1);
        }
        
                strncat(dst, tempstr, len-1);
        }
        

-       inflateEnd(&compressed_fpga_stream);
+       strncat(dst, "\n", len-1);

 
 

+       inflateEnd(&compressed_fpga_stream);

 }
 
 
 }
 
 


@@ -534,3 +560,16 @@ void SetAdcMuxFor(uint32_t whichGpio)
 
        HIGH(whichGpio);
 }
 
        HIGH(whichGpio);
 }

+
+void Fpga_print_status(void) {
+       Dbprintf("Fgpa");
+       switch(downloaded_bitstream) {
+               case FPGA_BITSTREAM_HF: Dbprintf("  mode....................HF"); break;
+               case FPGA_BITSTREAM_LF: Dbprintf("  mode....................LF"); break;
+               default:                Dbprintf("  mode....................%d", downloaded_bitstream); break;
+       }
+}
+
+int FpgaGetCurrent() {
+       return downloaded_bitstream;
+}