PATA hotplug

PATA hotplug

[Paul Wakeman]

Does libata support PATA hotplug?

I have a PCMCIA CF using TrueIDE mode and want to be able to hotplug CF
cards. Would I get hotplug for free if I convert the existing IDE
driver to a libata pata platform driver?

Thanks

Paul



       
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Re: PATA hotplug

[Alan Cox]

On Fri, 17 Aug 2007 08:56:35 -0700 (PDT)
Paul Wakeman <prwakeman@yahoo.com> wrote:

> Does libata support PATA hotplug?
> 
> I have a PCMCIA CF using TrueIDE mode and want to be able to hotplug CF
> cards. Would I get hotplug for free if I convert the existing IDE
> driver to a libata pata platform driver?

If your hardware supports PATA hotplug (most doesn't) then you can tell
the kernel to remove the device, pull it, add a new one and tell the
kernel to rescan (exactly as you do with any other scsi device).
Autodetect support right now is only in the SATA side and afaik no PATA
controller supports PATA hot plug autodetect.

Re: PATA hotplug

[Paul Wakeman]

--- Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

> On Fri, 17 Aug 2007 08:56:35 -0700 (PDT)
> Paul Wakeman <prwakeman@yahoo.com> wrote:
> 
> > Does libata support PATA hotplug?
> > 
> > I have a PCMCIA CF using TrueIDE mode and want to be able to
> hotplug CF
> > cards. Would I get hotplug for free if I convert the existing IDE
> > driver to a libata pata platform driver?
> 
> If your hardware supports PATA hotplug (most doesn't) then you can
> tell
> the kernel to remove the device, pull it, add a new one and tell the
> kernel to rescan (exactly as you do with any other scsi device).
> Autodetect support right now is only in the SATA side and afaik no
> PATA
> controller supports PATA hot plug autodetect.

My target is an embedded SoC which has PATA autodetect support.

First, I need to convert the vendor-supplied legacy IDE driver to a
PATA platform driver. Can you recommend best-of-breed existing PATA
drivers to use as a reference for this work? 

Thanks

-paul


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Re: PATA hotplug

[Alan Cox]

> My target is an embedded SoC which has PATA autodetect support.

Nice.

> First, I need to convert the vendor-supplied legacy IDE driver to a
> PATA platform driver. Can you recommend best-of-breed existing PATA
> drivers to use as a reference for this work? 

pata_platform is a dumb platform device driver and shows how to interface
to the platform layer. I'm guessing your hardware is a bit smarter in
which case you probably want to use pata_platform as a reference for
setting up platform class interfaces with arbitary port mappings and
something like pata_amd to see how the various cable detect, dma and pio
timing functions can be used.

If you've got hardware which supports master/slave but only single timing
registers take a look at the code in pata_oldpiix and the
oldpiix_qc_issue_prot function for how to do timing switching according
to the device, and pata_atiixp is a worked example of how to do clock
switching on the start/end of DMA operations.

Any other questions just ask