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Re: Does /devs/eth/arm/at91 work for SAM9 parts?
- From: Grant Edwards <grant dot b dot edwards at gmail dot com>
- To: ecos-discuss at sources dot redhat dot com
- Date: Mon, 29 Jun 2009 15:47:04 +0000 (UTC)
- Subject: [ECOS] Re: Does /devs/eth/arm/at91 work for SAM9 parts?
- References: <firstname.lastname@example.org> <20090627172633.GI16074@lunn.ch>
On 2009-06-27, Andrew Lunn <email@example.com> wrote:
> On Sat, Jun 27, 2009 at 04:40:24PM +0000, Grant Edwards wrote:
>> There appears to be plenty of support for Atmel's SAM7
>> (ARM7TDMI) series of parts, and I'm trying to find out how much
>> work it would be to support a SAM9 part (ARM926EJ-S). The SAM9
>> parts supposedly have the "same programming model and
>> peripheral set" or somesuch marketing-speak, so it presumably
>> should be easy to get a a SAM7 driver working for a SAM9 part.
>> For example, does anybody know if the /devs/eth/arm/at91 will
>> work for a SAM9 part?
> A short while back there was talk about rearranging the arm hal, to
> separate the arm7 stuff from the arm9. arm9 is an add on to arm7, so
> an arm9 target should be able to include both... However the talk
> petered out...
> Also, look back in the archive. Somebody did work on this.
> They had a rather invasive patch to make the driver work on
> one of the AT91SAM9 devices. But the marketing speak hides
> many untruths. The ethernet device worked mostly O.K, but the
> DMA was bust on the chipset he was using. Bad things happened
> when it DMAed from off chip RAM. The internal SRAM worked
> fine. So he had patches to memcpy the buffer from external RAM
> to internal SRAM then hand it over to the DMA. It was all
> rather ugly, and i don't remember a cleaned up patch ever
> being submitted.
According to what I've read in the forums at AT91.com, recent
SAM9 parts (like the G20) have had the Ethernet MAC FIFO sizes
increased so that you can use off-chip buffers -- so I won't
need the SRAM TX buffer option (famous last words).
Grant Edwards grante Yow! ... I want FORTY-TWO
at TRYNEL FLOATATION SYSTEMS
visi.com installed within SIX AND A
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