From: Dan Malek <dan@embeddededge.com>
To: kas turi <inox_kas@yahoo.com>, linuxppc-embedded@lists.linuxppc.org
Subject: Re: BD allocation and IDMA driver question
Date: Tue, 20 Aug 2002 00:35:37 -0400 [thread overview]
Message-ID: <3D61C719.4050607@embeddededge.com> (raw)
In-Reply-To: 20020820033306.23695.qmail@web21006.mail.yahoo.com
kas turi wrote:
> I would like to know what is the difference between
> m8260_cpm_hostalloc and m8260_dp_alloc.
The 'hostalloc' allocates from a small pool of host memory.
This is usually used for small FIFOs as there is only a
page or so for use by the entire system. The 'dp_alloc'
allocates from the CPM dual ported memory.
> .... The FCC driver
> uses the former API and the serial driver uses the
> latter API.
If you would read the comment in the FCC driver, you may
understand why :-)
> ..... When I try to use m8260_cpm_hostalloc to
> allocate buffer descriptor for the SPI driver the
> timesys 2.4 kernel hangs. When I use m8260_dp_alloc
> the SPI driver works.
The 'hostalloc' returns a kernel virtual address. You
have to convert this to a physical address for the CPM DMA.
> Has anybody developed a IDMA driver for 8260 for 2.4
> kernel?
There have been discussions about it on this mailing list.
You may wish to search the archives for more information.
-- Dan
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
prev parent reply other threads:[~2002-08-20 4:35 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-08-20 3:33 BD allocation and IDMA driver question kas turi
2002-08-20 4:35 ` Dan Malek [this message]
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