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Date:   Wed, 19 Apr 2023 23:09:05 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Palmer Dabbelt <palmer@dabbelt.com>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Conor Dooley <conor@kernel.org>, prabhakar.csengg@gmail.com,
        Arnd Bergmann <arnd@arndb.de>,
        Conor Dooley <conor.dooley@microchip.com>,
        geert+renesas@glider.be, heiko@sntech.de, guoren@kernel.org,
        ajones@ventanamicro.com, Paul Walmsley <paul.walmsley@sifive.com>,
        aou@eecs.berkeley.edu, samuel@sholland.org,
        linux-riscv@lists.infradead.org, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
        biju.das.jz@bp.renesas.com, prabhakar.mahadev-lad.rj@bp.renesas.com
Subject: Re: [PATCH v8 0/7] Add non-coherent DMA support for AX45MP
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On Wed, Apr 19, 2023 at 08:59:03AM -0700, Palmer Dabbelt wrote:
> IMO we should just take the support in Linux: trying to hide stuff behind the
> SBI leads to more more headaches than it's worth, we end up with a bunch of
> broken firmware to try and work around.  We've already got a mess here because
> of the D1 support, we might as well just live with it.

I strongly disagree.  Adding more and more per-vendor ops simply does
not scale.  We're getting us into a giant long-time mess that will be
unfixable.