Make sure the BIOS file ends on an aligned boundary.

If it does not, the address to which mkmscimg.py writes the CRC
and the address from which it is read could differ.

diff --git a/software/bios/linker.ld b/software/bios/linker.ld
index 74e83e3a653a4c640be750d7965ad84c75daed74..13b4bcaecb4c0f49c5522badbbb5a6c5baeffa0d 100644 (file)
--- a/software/bios/linker.ld
+++ b/software/bios/linker.ld
@@ -18,18 +18,12 @@ SECTIONS
                _frodata = .;
                *(.rodata .rodata.* .gnu.linkonce.r.*)
                *(.rodata1)
-               _erodata = .;
-       } > rom
 
-       /* We shouldn't have a .data section, but the GNU crapchain whines if we don't */
-       .data :
-       {
+               /* Make sure the file is aligned on disk as well
+                  as in memory; CRC calculation requires that. */
+               FILL(0);
                . = ALIGN(4);
-               _fdata = .;
-               *(.data .data.* .gnu.linkonce.d.*)
-               *(.data1)
-               *(.sdata .sdata.* .gnu.linkonce.s.*)
-               _edata = .;
+               _erodata = .;
        } > rom
 
        .bss :
@@ -51,6 +45,9 @@ SECTIONS
        {
                *(.eh_frame)
                *(.comment)
+               *(.data .data.* .gnu.linkonce.d.*)
+               *(.data1)
+               *(.sdata .sdata.* .gnu.linkonce.s.*)
        }
 }
 

diff --git a/software/bios/main.c b/software/bios/main.c
index 2a9aaa98655d091a625573cf92daab77340e54f2..3893141444ee476adb53c66d4262342f0bf1880a 100644 (file)
--- a/software/bios/main.c
+++ b/software/bios/main.c
@@ -409,7 +409,7 @@ static void do_command(char *c)
                printf("Command not found\n");
 }
 
-extern unsigned int _ftext, _edata;
+extern unsigned int _ftext, _erodata;
 
 static void crcbios(void)
 {
@@ -419,14 +419,14 @@ static void crcbios(void)
        unsigned int actual_crc;
 
        /*
-        * _edata is located right after the end of the flat
+        * _erodata is located right after the end of the flat
         * binary image. The CRC tool writes the 32-bit CRC here.
-        * We also use the address of _edata to know the length
+        * We also use the address of _erodata to know the length
         * of our code.
         */
        offset_bios = (unsigned int)&_ftext;
-       expected_crc = _edata;
-       length = (unsigned int)&_edata - offset_bios;
+       expected_crc = _erodata;
+       length = (unsigned int)&_erodata - offset_bios;
        actual_crc = crc32((unsigned char *)offset_bios, length);
        if(expected_crc == actual_crc)
                printf("BIOS CRC passed (%08x)\n", actual_crc);