Messages in this thread | | | Date | Wed, 9 Jun 1999 09:05:51 +0200 | From | Werner Almesberger <> | Subject | Re: 2.3 wish: integrate pcmcia into mainstream kernel |
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Alan Cox wrote: > For PCMCIA this partly exists. We have this feature (what DOS calls a point > enabler I believe) in the Psion5 palmtop port. Werner Almesberger has much > of this to hand.
I've posted that PCMCIA bit (for 2.3.3) a few weeks ago. It's also on ftp://lrcftp.epfl.ch/pub/people/almesber/junk/pcmcia.patch.gz
The basic idea is to find PCMCIA/CF IDE disks, which can be readily handled by the standard IDE driver. No hot-plugging or any of this.
The core part is cis.c, which checks the CIS if it describes a PCMCIA or CF device the IDE driver knows to handle. There are additional restrictions, such as only accepting fixed-address configurations (which is fine on the CL-PS7110/Psion S5/etc., but which may not be ideal on i386 - don't know how flexible those PCMCIA chips are when it comes to IO window mapping), and only understanding a single voltage. All this is, of course, fairly trivial to overcome, if needed.
Setting up the PCMCIA bridge, (*) etc., is left to the system-specific framework. See drivers/pcmcia/ in ftp://lrcftp.epfl.ch/pub/people/almesber/psion/crash+burn-22.patch.gz (for 2.2.1 with various ARM patches) for the full story.
(* I don't think we should assume that the PCMCIA bridge is competely operational when Linux runs: - Psion S5 case: EPOC (the native OS, run before Linux) enables everything we need, _except_ the interrupt. That one is blocked by an obscure proprietary chip which I only recently learned to program. - General case: we'll probably also be able to deal with embedded systems where there is no BIOS to enable the PCMCIA/CF.)
There's of course also the work of the MTD people, which I still have to look at.
- Werner
-- _________________________________________________________________________ / Werner Almesberger, DI-ICA,EPFL,CH werner.almesberger@lrc.di.epfl.ch / /_IN_R_131__Tel_+41_21_693_6621__Fax_+41_21_693_6610_____________________/
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