[cgl_discussion] [Fwd: hotswap and CGL (fwd)]

Steven Dake sdake at mvista.com
Wed Apr 30 14:02:26 PDT 2003


If you intend to use Compact PCI in linux kernel 2.4, the only hotswap 
support is available that I am aware of is MontaVista's Compact PCI 
PICMG 2.12 implmentation.  The hotswap software works exactly as 
described in the PICMG 2.12 specification.

In MontaVista's implementation, there is support for bus management for 
hotswapped devices.  Currently only network interfaces can be 
hotswapped, but the ifconfig of the device is automatic.  We also 
support backplane networking hotswap via MontaVista NET which treats the 
backplane PCI like a network interface (that you can use as a standard 
routable network interface).  If you hotswap scsi devices on a carrier 
board for example, the bus would be properly managed, but the SCSI layer 
doesn't include support to remove the physical devices or disks on the 
devices from the OS.  They could be closed down and the module unloaded, 
and then the hotswap code could be executed.

Other sorts of hotswap are supported such as ATCA hotswap of CPU, DISK, 
and SWITCH devices and disk hotswap that you may not find well 
implemented in the standard linux kernel but are implemented by MontaVista.

Hope this helps

Rusty Lynch wrote:

>On Wed, 2003-04-30 at 12:58, Mika Kukkonen wrote:
>>Please use cgl_discussion for CGL related questions; info at osdl.org
>>is something totally different ...
>>What comes to your question, there already is a lot of hotswap
>>functionality in 2.5 kernel, here is one place to look for
>>	http://linux-hotplug.sourceforge.net/?selected=pci
>>Of course some of the CGL compliant distros have implemented
>>additional stuff on top of that; I'll let them to comment on that.
>>-----Forwarded Message-----
>>>From: Bryce Harrington <bryce at osdl.org>
>>>To: mika at osdl.org
>>>Cc: info at osdl.org
>>>Subject: hotswap and CGL (fwd)
>>>Date: 30 Apr 2003 12:03:08 -0700
>>>---------- Forwarded message ----------
>>>Date: Wed, 30 Apr 2003 11:58:55 -0700
>>>From: "Bloch, Jack" <Jack.Bloch at icn.siemens.com>
>>>To: "'info at osdl.org'" <info at osdl.org>
>>>Subject: hotswap and CGL
>>>I am a developer at Siemens. We are validating CGL for use in a project.
>>>Hotswap is for us an extremely important feature. Is there any description
>>>of how the proposal will work for a cPCI environment? I have reasd the OSDL
>>>documents and do not find a description.
>>>Jack Bloch
>>>Siemens ICN
>>>phone                (561) 923-6550
>>>e-mail                jack.bloch at icn.siemens.com
>The kernel hotswap infrastructure was extended in the 2.5 kernel to
>support cPCI. 
>Some specific info:
>* The code can be found in linux/drivers/hotplug/cpci_* 
>* Scott Murry <scottm at somanetworks.com> maintains the cpci specific
>source, and Greg Kroah-Hartman <greg at kroah.com> is the owner of the
>entire hotswap infrastructure.
>* The infrastructure allows a hotswap system to be design like PICMG
>describes by writing a user space component to interface with the
>hotswap infrastructure via sysfs.  (Scott published a GPL version of
>such a user space component, but I do not recall the URL.)
>    --rustyl
>cgl_discussion mailing list
>cgl_discussion at lists.osdl.org

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