when CONFIG_PCI is not defined

[Martin Mares]

Hi Jeff,

> Would you mind reviewing pci.h to make sure that all necessary functions
> are exported when CONFIG_PCI is not defined?
> 
> I think that some of the recent PCI additions were not available for the
> !CONFIG_PCI case.  This is wrong IMHO because pci.h is specifically
> designed to provide support to drivers even when CONFIG_PCI is
> undefined.  It leads to much cleaner driver code.

   I'm not sure at all that this is the right way to go.

   With the old PCI interface, you could use

		struct pci_dev *dev = NULL;
		while (dev = pci_find_dev(VENDOR, DEVICE, dev)) {
			pci_enable_device(dev);
			init_your_device(dev->resource[0].start);
		}

and it magically went optimized away by the compiler if CONFIG_PCI wasn't
defined. With the new interface, it would look this way:

		int my_probe(struct pci_dev *dev)
		{
			pci_enable_device(dev);
			init_your_device(dev->resource[0].start);
			return 0;
		}

		struct pci_device_id my_ids[] = { ... };

		struct pci_driver my_driver {
			...
			id_table: my_ids,
			probe: my_probe,
		}

		{ pci_register_driver(&my_driver);

in which case nothing gets optimized away when compiling without CONFIG_PCI
and you end up with the driver full of dead code. Therefore to be on the
clean side of the glass, you need #ifdef CONFIG_PCI anyway, so there isn't
much sense in providing pci_register_driver() stub for PCI-less cases.

				Have a nice fortnight
-- 
Martin `MJ' Mares   <mj en ucw.cz>   http://atrey.karlin.mff.cuni.cz/~mj/
Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth
"Anything is good and useful if it's made of chocolate."

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