To whom it may concern,

a while ago (aprox. kernel 2.4.11) I succesfully played around with IDMA
on MPC855/860.
...
The code is NOT working on recent kernels (I pulled it yesterday).
I set up the IDMA. Trigger DREQ0 using a GPIO pin. SDMACK1 is going LOW
but then instead of toggeling it just stays LOW. And instead of
transfering data the MPC8xx just hangs.

Have there been changes in the DPRAM layout ..?

I (think I) figured out the problem:

I use
	m8xx_cpm_dpalloc( sizeof(idma_bd_t) );

to allocate space for the buffer descriptors in the DP ram.

The User Man says "Note that IBASE should be burst-aligned (divisible by
16)"
(Does the English "should be" means "have to be, otherwise everything
goes wrong!"???)

The older kernel versions always returned (by pure accident?) a
burst-aligned address (%16) (e.g. 0x850 offset from dpmem start). So
everything was fine.

The newer kernels return (by pure accident?) a NON burst-aligned address
(e.g. 0x0918) und the IDMA crashes.

So my workaround for now is to allocate more than I need and correct the
value for IBASE like
	ibase += ibase % 16

Could anyone think of a better solution? Since I waste at least 16 bytes
in the DPRAM.

BTW:
Where is Wolfgangs m8xx_cpm_dpfree() !?!?
I can't find it in the recent source trees.

Cheers,

Steven

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