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Message-ID: <d3ca1ec350d2442fb71eb006f8b57c45@EXMBX168.cuchost.com>
Date: Tue, 14 Feb 2023 07:11:02 +0000
From: JiaJie Ho <jiajie.ho@...rfivetech.com>
To: Christoph Hellwig <hch@...radead.org>,
Herbert Xu <herbert@...dor.apana.org.au>
CC: "David S . Miller" <davem@...emloft.net>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Emil Renner Berthing <kernel@...il.dk>,
Conor Dooley <conor.dooley@...rochip.com>,
"linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-riscv@...ts.infradead.org" <linux-riscv@...ts.infradead.org>
Subject: RE: [PATCH v2 4/4] crypto: starfive - Add hash and HMAC support
> -----Original Message-----
> From: Christoph Hellwig <hch@...radead.org>
> Sent: 14 February, 2023 2:13 PM
> To: Herbert Xu <herbert@...dor.apana.org.au>
> Cc: JiaJie Ho <jiajie.ho@...rfivetech.com>; David S . Miller
> <davem@...emloft.net>; Rob Herring <robh+dt@...nel.org>; Krzysztof
> Kozlowski <krzysztof.kozlowski+dt@...aro.org>; Emil Renner Berthing
> <kernel@...il.dk>; Conor Dooley <conor.dooley@...rochip.com>; linux-
> crypto@...r.kernel.org; devicetree@...r.kernel.org; linux-
> kernel@...r.kernel.org; linux-riscv@...ts.infradead.org
> Subject: Re: [PATCH v2 4/4] crypto: starfive - Add hash and HMAC support
>
> On Thu, Feb 09, 2023 at 05:43:34PM +0800, Herbert Xu wrote:
> > On Thu, Feb 09, 2023 at 09:33:06AM +0000, JiaJie Ho wrote:
> > >
> > > The DMA can only support 32-bit addressing.
> > > So, I am copying everything in case kernel allocated memory region >32-
> bit for a user app.
> >
> > Does your hardware support scatter-and-gather? If so you should at
> > least allocate individual pages rather than one contiguous buffer.
> >
> > Then you can allocate them on-demand rather than before-hand.
> >
> > It would also be nice to not do the copy if the input you were given
> > was in low memory (and contiguous if your hardware doesn't do SG).
>
> All of that is done by the DMA API, or more specifically swiotlb and does not
> need to be duplicated in individual drivers.
I'll update the driver accordingly.
Thanks Christoph and Herbert for the pointers.
Regards
Jia Jie
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