Messages in this thread | | | Date | Fri, 25 Jan 2002 00:43:20 +0100 (CET) | From | Gérard Roudier <> | Subject | Re: PCI #LOCK assertion |
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On Fri, 25 Jan 2002, chus Medina wrote:
> Hola, > > I need to create module to perform atomic transactions through the PCI bus > between the processor and an IDE hard disk. The PCI bus specifications 2.2 > point to the #LOCK signal to perform such a transaction. Is possible to > assert the #LOCK signal of the PCI bus using the Linux Kernel? How? I didnt > see any pointers in include/pci.h or anywhere in the source code. > > I will truly appreciate any help/pointers,
This has nothing to do with the kernel. This only depends on your CPU and on the PCI-HOST bridge of your system.
For example, some (all?) Intel PCI-HOST bridges will translate a LOCK prefixed memory READ to PCI into a locked PCI transaction. It is also possible to perform a locked READ/MODIFY transaction to PCI using the corresponding LOCK prefixed memory instruction.
I suggest you to download PCI-HOST bridge documents from Intel site and to look into them, if obviously you are interestested in such hardware.
Just, PCI-to-PCI bridges do not carry the PCI LOCK# protocol. As a result a subsystem relying on PCI LOCK# will not work (as expected) if PCI agents are talking through a PCI-to-PCI bridge.
Gérard.
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