From: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
To: Paul Burton <paulburton@kernel.org>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>,
linux-mips@vger.kernel.org, chenhc@lemote.com,
paul.burton@mips.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] MIPS: Introduce aligned IO memory operations
Date: Fri, 24 Jan 2020 15:07:51 +0100 [thread overview]
Message-ID: <20200124140751.GA17030@alpha.franken.de> (raw)
In-Reply-To: <20200122184506.7zbzetn5xturxamj@pburton-laptop>
On Wed, Jan 22, 2020 at 10:45:06AM -0800, Paul Burton wrote:
> Hi Jiaxun,
>
> On Tue, Jan 14, 2020 at 08:23:43PM +0800, Jiaxun Yang wrote:
> > Some platforms, such as Loongson64 or QEMU/KVM, don't support unaligned
> > instructions like lwl or lwr in IO memory access. However, our current
> > IO memcpy/memset is wired to the generic implementation, which leads
> > to a fatal result.
>
> Hmm, I wonder if we should just do this unconditionally on all systems.
> I can't think of a reason it'd ever be a good idea to use lwl/lwr on an
> MMIO device. Any thoughts on that?
depends on the type of device. I can see benefits for framebuffers
and memory devices since memset/memcpy are more optimised than the
function in this patch.
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
next prev parent reply other threads:[~2020-01-24 14:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 12:23 [PATCH] MIPS: Introduce aligned IO memory operations Jiaxun Yang
2020-01-18 14:41 ` Philippe Mathieu-Daudé
2020-01-18 15:13 ` Jiaxun Yang
2020-01-22 18:45 ` Paul Burton
2020-01-24 14:07 ` Thomas Bogendoerfer [this message]
2020-01-25 3:31 ` Jiaxun Yang
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