brun_mtd

[ollie lho]

On Wed, 2003-05-21 at 21:31, steven james wrote:
> Greetings,
> 
> The DoC has hardware support for a 512B boot plock. On powerup, it loads
> the first block into a block that 'just happens' to map the end of the
> block at 0xf000:0xfff0. If the first block has an ECC error, the second
> block is copied instead (so two copies of docipl).
> 
> 
> On Wed, 21 May 2003, Xavier Pegenaute wrote:
> 
> > Hello,
> > 
> > In the script of src/util/mtd/burn_mtd there are these lines ..
> > 
> > - dd conv=notrunc conv=sync bs=65536 if=${linux} of=vmlinux.bin.gz.block
> > With this we if exist we don't trunc and fix the size of 
> > vmlinux.bin.gz.block, if it's more smaller than 65536 we put 0 until 
> > this size.
> > 
> > - dd conv=notrunc conv=sync bs=63k if=${linuxbios} of=linuxbios.block
> > The same but with 63k.
> > 
> > - dd conv=notrunc if=docipl of=/dev/mtd0
> > We write without trunc /dev/mtd0 with the source of docipl.
> > 
> > - dd conv=notrunc if=docipl of=/dev/mtd0 seek=1
> > The same but this time we skip 1 block of "bs" (i supose that we can 
> > remind the value of bs in the last line, then sizeof(docipl) ).
> > 
> > - dd conv=notrunc if=linuxbios.block of=/dev/mtd0 seek=2
> > Without trunc we write linuxbios.block to mtd, skipping 2 times the last 
> > size (sizeof(docipl) ).
> > 
> > - dd conv=notrunc if=vmlinux.bin.gz.block of=/dev/mtd0 seek=128
> > Now without trunc write vmlinux skipping 128 times the size of 
> > linuxbios.block.
> > 
> > 
> > My questions, are:
> > 
> > Why we write two times docipl ?

First of all, you are way wrong with what seek=# means. It skips # of
(output) blocks of the output device. It has nothing to do with
sizeof(some image). Please man dd for detail.

There are two copies for IPL one at offset 0 the other at offset 512B
(seek=1).

> > And why we skip 128 times the size of linuxbios.block ? (i supose that 
> > i'm wrong, any one can help me with these)
> >

The size of linuxbios.block is 63kB plus the 2 copies of IPL == 64kB ==
128 blocks.

-- 
ollie lho <ollie at sis.com.tw>