From: Christoph Hellwig <hch@lst.de>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Prabhakar <prabhakar.csengg@gmail.com>,
"Conor.Dooley" <conor.dooley@microchip.com>,
"Geert Uytterhoeven" <geert+renesas@glider.be>,
"Heiko Stübner" <heiko@sntech.de>, guoren <guoren@kernel.org>,
"Andrew Jones" <ajones@ventanamicro.com>,
"Paul Walmsley" <paul.walmsley@sifive.com>,
"Palmer Dabbelt" <palmer@dabbelt.com>,
"Albert Ou" <aou@eecs.berkeley.edu>,
"open list:RISC-V ARCHITECTURE" <linux-riscv@lists.infradead.org>,
"open list" <linux-kernel@vger.kernel.org>,
devicetree@vger.kernel.org,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
"Lad, Prabhakar" <prabhakar.mahadev-lad.rj@bp.renesas.com>,
"Philipp Tomsich" <philipp.tomsich@vrull.eu>,
"Nathan Chancellor" <nathan@kernel.org>,
"Atish Patra" <atishp@rivosinc.com>,
"Anup Patel" <apatel@ventanamicro.com>,
"Tsukasa OI" <research_trasio@irq.a4lg.com>,
"Jisheng Zhang" <jszhang@kernel.org>,
"Mayuresh Chitale" <mchitale@ventanamicro.com>,
"Christoph Hellwig" <hch@lst.de>, "Will Deacon" <will@kernel.org>
Subject: Re: [RFC PATCH v6 1/6] riscv: mm: dma-noncoherent: Switch using function pointers for cache management
Date: Tue, 10 Jan 2023 08:01:44 +0100 [thread overview]
Message-ID: <20230110070144.GG10289@lst.de> (raw)
In-Reply-To: <45d6eb0c-cbe3-4a83-aa12-3483638473ae@app.fastmail.com>
On Mon, Jan 09, 2023 at 01:59:12PM +0100, Arnd Bergmann wrote:
> I had another look at the arm64 side, which (like the zicbom
> variant) uses 'clean' on dma_sync_single_for_device(DMA_FROM_DEVICE),
> as that has changed not that long ago, see
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c50f11c6196f45c92ca48b16a5071615d4ae0572
which IIRC has been reverted recently.
> I'm still not sure what the correct set of operations has
> to be, but nothing in that patch description sounds ISA
> or even microarchitecture specific.
Nothing is ISA specific, and the only micro architecture related thing
is if the specific core can speculate memory accesses. See the table
in arch/arc/mm/dma.c for details.
And as commented on the arm64 patch I really hate architectures getting
creative here, as I'd much prefer to move the choice of primitives to
the core DMA code and just provide helpers to invalidate/writeback/
writeback+invalidate from the architectures eventually.
next prev parent reply other threads:[~2023-01-10 7:02 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-06 18:55 [PATCH v6 0/6] RISC-V non-coherent function pointer based cache management operations + non-coherent DMA support for AX45MP Prabhakar
2023-01-06 18:55 ` [RFC PATCH v6 1/6] riscv: mm: dma-noncoherent: Switch using function pointers for cache management Prabhakar
2023-01-06 22:31 ` Arnd Bergmann
2023-01-06 23:29 ` Conor Dooley
2023-01-07 21:52 ` Arnd Bergmann
2023-01-07 22:21 ` Conor Dooley
2023-01-08 16:37 ` Conor Dooley
2023-01-07 22:10 ` Lad, Prabhakar
2023-01-08 0:07 ` Arnd Bergmann
2023-01-09 12:03 ` Lad, Prabhakar
2023-01-09 12:59 ` Arnd Bergmann
2023-01-09 13:27 ` Conor Dooley
2023-01-10 7:01 ` Christoph Hellwig [this message]
2023-01-10 15:03 ` Arnd Bergmann
2023-01-10 15:11 ` Will Deacon
2023-01-13 5:48 ` Christoph Hellwig
2023-01-20 17:04 ` Arnd Bergmann
2023-01-21 14:37 ` Christoph Hellwig
2023-01-21 19:30 ` Arnd Bergmann
2023-01-22 7:27 ` Christoph Hellwig
2023-01-22 11:04 ` Arnd Bergmann
2023-01-23 14:46 ` Christoph Hellwig
2023-01-06 23:47 ` Conor Dooley
2023-01-07 22:36 ` Lad, Prabhakar
2023-01-06 18:55 ` [PATCH v6 2/6] riscv: asm: vendorid_list: Add Andes Technology to the vendors list Prabhakar
2023-01-06 18:55 ` [PATCH v6 3/6] riscv: errata: Add Andes alternative ports Prabhakar
2023-01-06 21:44 ` Conor Dooley
2023-01-06 18:55 ` [PATCH v6 4/6] dt-bindings: cache: r9a07g043f-l2-cache: Add DT binding documentation for L2 cache controller Prabhakar
2023-01-06 21:53 ` Conor Dooley
2023-01-07 20:43 ` Lad, Prabhakar
2023-01-09 12:15 ` Geert Uytterhoeven
2023-01-09 13:14 ` Lad, Prabhakar
2023-01-06 18:55 ` [PATCH v6 5/6] cache: Add L2 cache management for Andes AX45MP RISC-V core Prabhakar
2023-01-07 0:09 ` Conor Dooley
2023-01-07 20:49 ` Lad, Prabhakar
2023-01-06 18:55 ` [PATCH v6 6/6] soc: renesas: Kconfig: Select the required configs for RZ/Five SoC Prabhakar
2023-01-06 23:49 ` Conor Dooley
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