Messages in this thread | | | From | Arnd Bergmann <> | Date | Tue, 21 Dec 2021 10:17:27 +0100 | Subject | Re: [PATCH v2] asm-generic: introduce io_stop_wc() and add implementation for ARM64 |
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On Tue, Dec 21, 2021 at 4:55 AM Xiongfeng Wang <wangxiongfeng2@huawei.com> wrote: > > For memory accesses with write-combining attributes (e.g. those returned > by ioremap_wc()), the CPU may wait for prior accesses to be merged with > subsequent ones. But in some situation, such wait is bad for the > performance. > > We introduce io_stop_wc() to prevent the merging of write-combining > memory accesses before this macro with those after it. > > We add implementation for ARM64 using DGH instruction and provide NOP > implementation for other architectures. > > Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com> > Suggested-by: Will Deacon <will@kernel.org> > Suggested-by: Catalin Marinas <catalin.marinas@arm.com> > --- > v1->v2: change 'Normal-Non Cacheable' to 'write-combining'
For asm-generic:
Acked-by: Arnd Bergmann <arnd@arndb.de>
Will, Catalin: if you are happy with this version, please merge it through the arm64 tree.
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