On Fri, Apr 22, 2016 at 06:08:46PM +0100, Robin Murphy wrote: > On 21/04/16 17:18, Will Deacon wrote: > >On Wed, Apr 13, 2016 at 06:13:00PM +0100, Robin Murphy wrote: > >>Whilst commit 9439eb3ab9d1 ("asm-generic: io: implement relaxed > >>accessor macros as conditional wrappers") makes the *_relaxed forms of > >>I/O accessors universally available to drivers, in cases where writeq() > >>is implemented via the io-64-nonatomic helpers, writeq_relaxed() will > >>end up falling back to writel() regardless of whether writel_relaxed() > >>is available (identically for s/write/read/). > >> > >>Add corresponding relaxed forms of the nonatomic helpers to delegate > >>to the equivalent 32-bit accessors as appropriate. > >> > >>CC: Arnd Bergmann <a...@arndb.de> > >>CC: Christoph Hellwig <h...@lst.de> > >>CC: Darren Hart <dvh...@linux.intel.com> > >>CC: Hitoshi Mitake <mitake.hito...@lab.ntt.co.jp> > >>Signed-off-by: Robin Murphy <robin.mur...@arm.com> > >>--- > >> include/linux/io-64-nonatomic-hi-lo.h | 25 +++++++++++++++++++++++++ > >> include/linux/io-64-nonatomic-lo-hi.h | 25 +++++++++++++++++++++++++ > >> 2 files changed, 50 insertions(+) > >> > >>diff --git a/include/linux/io-64-nonatomic-hi-lo.h > >>b/include/linux/io-64-nonatomic-hi-lo.h > >>index 11d7e84..1a85566 100644 > >>--- a/include/linux/io-64-nonatomic-hi-lo.h > >>+++ b/include/linux/io-64-nonatomic-hi-lo.h > >>@@ -21,6 +21,23 @@ static inline void hi_lo_writeq(__u64 val, volatile void > >>__iomem *addr) > >> writel(val, addr); > >> } > >> > >>+static inline __u64 hi_lo_readq_relaxed(const volatile void __iomem *addr) > >>+{ > >>+ const volatile u32 __iomem *p = addr; > >>+ u32 low, high; > >>+ > >>+ high = readl_relaxed(p + 1); > >>+ low = readl_relaxed(p); > >>+ > >>+ return low + ((u64)high << 32); > >>+} > >>+ > >>+static inline void hi_lo_writeq_relaxed(__u64 val, volatile void __iomem > >>*addr) > >>+{ > >>+ writel_relaxed(val >> 32, addr + 4); > >>+ writel_relaxed(val, addr); > >>+} > > > >Could we not generate the _relaxed variants with some macro magic? > > We _could_ - indeed I started doing that, but then decided that the > obfuscation of horrible macro-templated functions wasn't worth saving a > couple of hundred bytes in some code that isn't exactly difficult to > maintain and has needed touching once in 4 years. > > If you did want to go down the macro route, I may as well also generate both > lo-hi and hi-lo headers all from a single template, it'd be really clever... > <alarm bells> ;)
I certainly wasn't suggesting any more than the obvious macroisation, but I'll leave it up to Arnd, as I think this falls on his lap. Will _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu