Re: [patch 2.6.24-rc1] resource_len() utility function

[Jeff Garzik <jeff@garzik.org>]

Alan Cox wrote:
> On Wed, 24 Oct 2007 18:20:52 -0700
> David Brownell <david-b@pacbell.net> wrote:
> 
>> Add a new resource_len() function, so drivers can start using this
>> instead of driver-private code for a common idiom.  The call can be
>> useful with at least:
>>
>>  - request_region(), release_region()
>>  - request_mem_region(), release_mem_region()
>>  - ioremap()
>>
>> Candidate drivers include those using platform or PNP busses, and
>> maybe some others.  PCI already has a similar function.
>>
>> This patch also updates a representative set of drivers in two
>> subsystems to use this call (SPI, and USB peripheral/gadget).
> 
> PCI also increasingly is using functions that allow the user to choose to
> map a resource as a resource (eg pci_iomap). So is it better to have
> functions request_mem_resource(res)  free_mem_resource(res) and similar
> instead or as well ?


With regards to resource reservation...  IMO we should mimic struct 
pci_dev and add struct resource[] to struct device.

Just like we have pci_request_regions(), we should also be able to 
easily to a dev_request_regions().  the implementation should be very 
close to pci_request_region() and pci_release_region().

Then a dev_iomap() analogue to pci_iomap() should be pretty 
straightforward to create.

	Jeff