Messages in this thread | | | Date | Wed, 15 Jan 2003 17:23:24 -0600 (CST) | From | Bret Indrelee <> | Subject | Forcing PCI-PCI bridge to have memory resources |
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I'm working with Linux version 2.4.18-xfs with hotswap support.
I'm trying to make a PCI-PCI bridge always have a minimum of 1MB of memory address space allocated to it. I know that the BIOS we are using always (correctly, by spec) sets a bridge with no devices behind it to disable the memory window. It does this by setting the MEM_LIMIT < MEM_BASE.
I've been going through the sources in drivers/pci, trying to figure out how things are set up. At the time of the pci scan, the resources are usually initialized (in bci_read_breidge_bases) by doing a read of the bridge registers and setting the resource values appropropriately.
For the disabled bridges, the resources are copied from the parent which in this case results in 0 being set in flags, start and end.
It looks like I will want to call pci_assign_resource(dev, 1); in order to give it a memory window, but I'm not sure how to initialize the resources so they are assigned correctly.
Our situation is similiar to what a hotswap CPCI system should encounter when a hotswap device is inserted behind a previously empty PCI-PCI bridge.
Any help people can give would be greatly appreciated.
-Bret
-- Bret Indrelee QLogic Corporation Bret.Indrelee@qlogic.com 6321 Bury Driver, St 13, Eden Prairie, MN 55346
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