[ECOS] blib_get_block() uses blocks instead of bytes? flashiodev_bread() uses bytes instead of blocks?

[Garth Zeglin <avantgarth at yahoo dot com>]

Dear ecos-discuss,

In summary: 
  It appears that blib_get_block() is calling
cyg_io_bread()
  with a length argument of 1, intending to read one
block; however
  cyg_io_bread expects a length parameter in bytes.

  It appears that flashiodev_bread() is treating the
'pos' parameter
  in units of bytes, but that it is supplied in units
of blocks.

Am I correct that this is a bug?  I'm asking here
first in case there
is something obvious I am missing.  I am using the
current public CVS
sources.  It's not clear what is the definition of
cyg_io_bread(), the
only documentation I found was on the ecoscentric web
site:
http://www.ecoscentric.com/ecospro/doc/html/ecospro-ref/diskio-usage.html

My trivial fix for
packages/io/flash/current/src/flashiodev.c

*** flashiodev.c        Fri Nov 25 23:44:23 2005
--- flashiodev.c.~1.8.~ Thu Apr 29 08:37:56 2004
***************
*** 122,123 ****
-       pos *= 512;
- 
--- 121 ----


My trivial fix for
packages/services/blib/current/src/blib.c

*** blib.c      Fri Nov 25 23:47:30 2005
--- blib.c.~1.3.~       Wed Aug  3 22:47:51 2005
***************
*** 360 ****
!         len = 512;
--- 360 ----
!         len = 1;


My full story, in case anyone searches for this later:

I'm new to eCos and as a test I set out to mount a
FAT12 filesystem
contained within a synthetic flash image.  I'm using
the Linux
synthetic target and synthetic flash device.  I
observed that the
mount failed because only one byte of the boot record
was being read.

Here is the call chain:
  mount ("/dev/flash1", "/", "fatfs" )
    ....
      fatfs_init()                                    
          (fatfs_supp.c)
        read_boot_record()
          disk_read ( *len == 90 bytes, pos == 0 )
            cyg_blib_read() (*len == 90, bnum == 0,
pos == 0)     (blib.c)
              blib_get_block ( num == 0 )
                 calls bl->bread_fn ( *len == 1,
block->num == 0)
                ....
                  flashiodev_bread( len == 1, pos == 0
)         (flashiodev.c)

The result I observe is that only one byte is read by
flashiodev,
instead of the 90 bytes requested by
read_boot_record().  Adding the
two patches above fixed this, and the file system
mounts and the root
directory can be read.

Other notes: 

I used /sbin/mkdosfs to create the filesystem on the
synth.flash
file. It begins directly with a FBR, there is no MBR
in the file.
It is only 1M so it ends up as FAT12.

I configured CYGNUM_IO_FLASH_BLOCK_OFFSET_1 to zero;
the default
configuration size for the synthetic flash is 1024k,
and the default
block offset puts the start of the block device past
the end.

    Thanks,

    Garth Zeglin



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