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List:       linux-arm-kernel
Subject:    Re: Direct-mapped Compact Flash on ARM9
From:       Russell King - ARM Linux <linux () arm ! linux ! org ! uk>
Date:       2004-07-01 21:27:45
Message-ID: 20040701222745.C8980 () flint ! arm ! linux ! org ! uk
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On Thu, Jul 01, 2004 at 04:15:16PM -0500, James Graves wrote:
> I should have mentioned that I'm trying to interface to an I/O card
> (specifically a wireless LAN card).

Ah, so it's not a CF card.

So yet again the industry chooses a completely confusing name for
something which isn't what the name describes...  Sigh.

soc_common/pxa_base/sa11xx_base provide a relatively thin layer of
support for direct-mapped devices, as will any statically mapped
PCMCIA socket driver.

However, and this is a big however, when dealing with any ISA-like
peripheral you MUST repeat MUST note what the ISA-like device does
with the IOCS16 signal.

To give an example:

- A NE2K PCMCIA net card always transfers byte data on the low 8 bits
  of the data bus.
- A 3c589 PCMCIA net card always transfers odd-address byte data on
  the high 8 bits of the data bus.

If you ignore IOCS16 you completely loose the ability to communicate
with 16-bit PCMCIA cards since you can never tell which byte lane odd
byte accesses will return data.

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