(Fwd) Re: DOSFS bug fixes, IDE drivers and sample released
Angelo Fraietta
angelo_f at bigpond.com
Mon Mar 17 22:40:28 UTC 2003
Where are the samples for these? I want to test this out for pc386. Does
it support pc386 yet?
Eugeny S. Mints wrote:
>On Mon, 3 Mar 2003, Thomas Doerfler wrote:
>
>>------- Forwarded message follows -------
>>From: "Thomas Doerfler" <Thomas.Doerfler at imd-systems.de>
>>Organization: IMD
>>To: Chris Caudle <chris at chriscaudle.org>
>>Date sent: Mon, 03 Mar 2003 09:01:38 +0100
>>Subject: Re: DOSFS bug fixes, IDE drivers and sample released
>>Copies to: Thomas Doerfler <Thomas.Doerfler at imd-systems.de>
>>Priority: normal
>>
>>
>>
>>>On Sunday 02 March 2003 9:48 am, Joel Sherrill wrote:
>>>
>>>>>filed as PR 367/368/369 in the GNATS system, see:
>>>>>
>>>Does the driver filed in PR 368 support DMA transfer yet, or programmed I/O
>>>only?
>>>
>>It is really a minimal implementation, supporting PIO mode.
>>Actually I am not so aware about various IDE transfer modes,
>>the integration of DMA into the PC architecture an so on, my
>>goal was to implement at least basic harddisc support.
>>
>
>Actually the answer is the following: DMA and POI modes are
>entities which belong to generic high level ATA driver
>implemented in ata.c file. In other words wether the data
>will be transferred in PIO or DMA mode depends on ATA
>commands issued. In general, low level IDE drivers (as
>Thomas drivers written for i386 and mbx8xx) just "pass" ATA commands to an
>IDE chip just by providing ability for writing any data to a
>chip registers. In addition to the basic
>functionality described above, current IDE drivers have
>several routines for optimization of data read/write in PIO
>mode (*_ide_read_block/*pc386_ide_write_block).
>
>So, any low level IDE driver has ability to support PIO and
>DMA modes by definition (but of course current low IDE
>drivers may need some update for DMA support) and the issue
>depends on generic ATA driver implementaion. Unfortunately, current ATA
>driver implementation supports only PIO mode, but from the
>beggining was designed to allow easy extension (I
>mean addition of new ATA commands). So, generic ATA driver
>should be modified for DMA mode support.
>
>>So here is a lot of space to improve things :-)
>>
>
>Agree:)))
>
>Hope, this helps,
> Eugeny
>
>
--
Angelo Fraietta
PO Box 859
Hamilton NSW 2303
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