Re: [PATCH v9 0/8] pci: add pci_iomap_wc() and pci_ioremap_wc_bar()
From: Luis R. Rodriguez <hidden>
Date: 2015-07-17 20:29:37
Also in:
linux-pci, lkml, xen-devel
On Wed, Jul 08, 2015 at 06:54:11PM -0700, Luis R. Rodriguez wrote:
From: "Luis R. Rodriguez" <redacted> Ingo, Boris is on vacation, he picked up these patches on his bp#tip-mm tree [0] and they have baked there for a while now. That tree receives 0-day bot testing, but other than that its not clear what other tests were run on these patches. Boris modified the commit logs a bit, and made one optimizaiton to bail early on an PCI ioremap call when it should. These patches have no modifications from what is on Boris' tree and tip-mm branch. The 0 day build bot did find issues on Boris' tree but those are related to ioremap_uc() (already upstream) and its first use on atyfb (not upstream) -- I will be addressing a fix for that ioremap_uc() issue through another patch series prior to posting the final set for atyfb which makes use of ioremap_uc(). No issues have been found with this series. Benh did note some possible issues with expectations with what is done for write-combining for PowerPC [1] but the issue is a rather general long standing issue with semantics of ioremap -- in the case for ioremap_wc() on PowerPC benh notes that writel() will never write-combine as it uses too heavy barriers. Benh notes that although writel_relaxed() today is identical to writel() this can be changed. There are other general semantics issues with ioremap() variant calls -- we seem to have all gotten together to discuss all these issues on a thread where Dan Williams is proposing to "unify ioremap prototypes and macro aliases" [1], folks intersted on these issues or semantic concerns can drop in and chime there. Let me know if these are OK or if there are any questions. [0] http://lkml.kernel.org/r/20150625204703.GC4898@pd.tnic [1] http://lkml.kernel.org/r/20150707095012.GQ7021@wotan.suse.de
Ingo, Just a friendly reminder. Let me know if there are any issues or questions. Luis