From: Anup Patel <anup@brainfault.org>
To: Drew Fustini <drew@beagleboard.org>
Cc: "Christoph Hellwig" <hch@lst.de>, "Guo Ren" <guoren@kernel.org>,
"Anup Patel" <anup.patel@wdc.com>,
"Palmer Dabbelt" <palmerdabbelt@google.com>,
wefu@redhat.com, "Wei Wu (吴伟)" <lazyparser@gmail.com>,
linux-riscv <linux-riscv@lists.infradead.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
linux-sunxi@lists.linux.dev, "Guo Ren" <guoren@linux.alibaba.com>,
"Paul Walmsley" <paul.walmsley@sifive.com>
Subject: Re: [PATCH RFC 0/3] riscv: Add DMA_COHERENT support
Date: Wed, 19 May 2021 12:44:55 +0530 [thread overview]
Message-ID: <CAAhSdy3C1owsbY_9gkxkhWfCXnL_noow7F4t=5+j7q+AJO3pZQ@mail.gmail.com> (raw)
In-Reply-To: <20210519065431.GB3076809@x1>
On Wed, May 19, 2021 at 12:24 PM Drew Fustini <drew@beagleboard.org> wrote:
>
> On Wed, May 19, 2021 at 08:06:17AM +0200, Christoph Hellwig wrote:
> > On Wed, May 19, 2021 at 02:05:00PM +0800, Guo Ren wrote:
> > > Since the existing RISC-V ISA cannot solve this problem, it is better
> > > to provide some configuration for the SOC vendor to customize.
> >
> > We've been talking about this problem for close to five years. So no,
> > if you don't manage to get the feature into the ISA it can't be
> > supported.
>
> Isn't it a good goal for Linux to support the capabilities present in
> the SoC that a currently being fab'd?
>
> I believe the CMO group only started last year [1] so the RV64GC SoCs
> that are going into mass production this year would not have had the
> opporuntiy of utilizing any RISC-V ISA extension for handling cache
> management.
The current Linux RISC-V policy is to only accept patches for frozen or
ratified ISA specs.
(Refer, Documentation/riscv/patch-acceptance.rst)
This means even if emulate CMO instructions in OpenSBI, the Linux
patches won't be taken by Palmer because CMO specification is
still in draft stage.
Also, we all know how much time it takes for RISCV international
to freeze some spec. Judging by that we are looking at another
3-4 years at minimum.
Regards,
Anup
next prev parent reply other threads:[~2021-05-19 7:15 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-19 5:04 [PATCH RFC 0/3] riscv: Add DMA_COHERENT support guoren
2021-05-19 5:04 ` [PATCH RFC 1/3] riscv: pgtable.h: Fixup _PAGE_CHG_MASK usage guoren
2021-05-19 5:04 ` [PATCH RFC 2/3] riscv: Add DMA_COHERENT for custom PTE attributes guoren
2021-05-19 5:04 ` [PATCH RFC 3/3] riscv: Add SYNC_DMA_FOR_CPU/DEVICE for DMA_COHERENT guoren
2021-05-19 6:32 ` Guo Ren
2021-05-19 5:20 ` [PATCH RFC 0/3] riscv: Add DMA_COHERENT support Christoph Hellwig
2021-05-19 5:48 ` Guo Ren
2021-05-19 5:55 ` Christoph Hellwig
2021-05-19 6:09 ` Guo Ren
2021-05-19 6:44 ` Drew Fustini
2021-05-19 6:53 ` Christoph Hellwig
2021-05-20 1:45 ` Guo Ren
2021-05-20 5:48 ` Christoph Hellwig
2021-06-06 18:14 ` Nick Kossifidis
2021-06-07 0:04 ` Guo Ren
2021-06-07 2:16 ` Nick Kossifidis
2021-06-07 3:19 ` Guo Ren
2021-06-07 6:27 ` Christoph Hellwig
2021-06-07 6:41 ` Guo Ren
2021-06-07 6:51 ` Christoph Hellwig
2021-06-07 7:46 ` Guo Ren
2021-06-08 15:00 ` David Laight
2021-06-08 15:32 ` 'Christoph Hellwig'
2021-06-08 16:11 ` David Laight
2021-06-07 8:35 ` Nick Kossifidis
2021-06-09 3:28 ` Guo Ren
2021-06-09 6:05 ` Jisheng Zhang
2021-06-09 9:45 ` Nick Kossifidis
2021-06-09 12:43 ` Guo Ren
2021-05-19 6:05 ` Guo Ren
2021-05-19 6:06 ` Christoph Hellwig
2021-05-19 6:11 ` Guo Ren
2021-05-19 6:54 ` Drew Fustini
2021-05-19 6:56 ` Christoph Hellwig
2021-05-19 7:14 ` Anup Patel [this message]
2021-05-19 8:25 ` Damien Le Moal
2021-05-20 1:47 ` Guo Ren
2021-05-20 1:59 ` Guo Ren
2021-05-22 0:36 ` Guo Ren
2021-05-30 0:30 ` Palmer Dabbelt
2021-06-03 4:13 ` Palmer Dabbelt
2021-06-03 6:00 ` Anup Patel
2021-06-03 15:39 ` Palmer Dabbelt
2021-06-04 9:02 ` David Laight
2021-06-04 9:53 ` Arnd Bergmann
2021-06-04 14:47 ` Guo Ren
2021-06-04 16:12 ` Palmer Dabbelt
2021-06-04 21:26 ` Arnd Bergmann
2021-06-04 22:10 ` Palmer Dabbelt
2021-06-08 12:26 ` Guo Ren
2021-06-06 17:11 ` Guo Ren
2021-06-07 3:38 ` Anup Patel
2021-06-07 4:22 ` Guo Ren
2021-06-07 4:47 ` Anup Patel
2021-06-07 5:08 ` Guo Ren
2021-06-07 5:13 ` Guo Ren
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