lkml.org 
[lkml]   [2015]   [Aug]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC] asm-generic/pci_iomap.h: make custom PCI BAR requirements explicit
On Fri, Aug 28, 2015 at 05:17:27PM -0700, Luis R. Rodriguez wrote:
> From: "Luis R. Rodriguez" <mcgrof@suse.com>
>
> The S390 architecture requires a custom pci_iomap() implementation
> as the asm-generic implementation assumes there are disjunctions
> between PCI BARs, and on S390 PCI BAR are not disjunctive, S390 requires
> the bar parameter in order to find the corresponding device and create
> the mapping cookie.
>
> This clash with the asm-generic pci_iomap() implementation is implicit,
> there are no current semantics to make this incompatability explicit.
> Make the S390 PCI BAR non-disjunction incompatibility explicit, and
> also pave the way for alternative incompatibilities to be defined.
>
> While at it, as with the ioremap*() variants, since we have no clear
> semantics yet well defined provide a solution for them that returns
> NULL. This allows architectures to move forward by defining pci_ioremap*()
> variants without requiring immediate changes to all architectures. Each
> architecture then can implement their own solution as needed and
> when they get to it.

Now that you have the config symbol available why not move the S390
implementation to generic code based on that can kill of
asm/pci_iomap.h? Seems like we're really not dealing with something
inherent to the architecture, but two possible implementations based
on architecture constraints.


\
 
 \ /
  Last update: 2015-08-29 17:41    [W:0.759 / U:3.372 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site