Re: Linux hot swap support

From: Greg KH (
Date: Wed Sep 18 2002 - 16:47:41 EST

On Wed, Sep 18, 2002 at 05:37:50PM -0400, Bloch, Jack wrote:
> At the moment, I only support removal. The way it works is as follows.
> Upon system start up my device driver detects all of the boards which are
> present (I support up to six). For each board it allocates the necessary I/O
> lists memory needed for operation. All addresses are then mapped to user
> space with a mmap interface. Now, all HW is accessible from user space. For
> each device, an ISR is installed. As soon as the ejector handle for a
> particular device is opened, the board (which is a Motorola 68060 based
> board) issues an interrupt to me. I will shut this board down and
> de-allocate any of the previously reserved resources. What is not so easy is
> to perform the insert. I thought about allocating memory becessary for a
> maximum configuration, but I would still need to get the insertion event.
> But anyway since our device (even though it has multiple boards internally)
> is seen as a monolithic device from the main controlling host, the loss of a
> single board causes it to be taken out of service.

Hm, you might want to take a look at the cPCI patches from Scott Murray,
he has a solution for the resource and insertion problem that will
probably work for you. You can find the patches on the pcihpd-discuss
mailing list, and I think they were also posted to lkml in the past too.
He's working on cleaning them up a bit for inclusion in the main kernel

Hope this helps,

greg k-h
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