From: Gregory CLEMENT <gregory.clement@bootlin.com>
To: Aleksander Jan Bajkowski <olek2@wp.pl>,
andrew@lunn.ch, sebastian.hesselbarth@gmail.com, robh@kernel.org,
krzk+dt@kernel.org, conor+dt@kernel.org,
linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: Aleksander Jan Bajkowski <olek2@wp.pl>
Subject: Re: [PATCH] arm64: dts: marvell: armada-37xx: mark EIP97 as dma-coherent
Date: Mon, 01 Jun 2026 10:08:00 +0200 [thread overview]
Message-ID: <87zf1eznrz.fsf@BLaptop.bootlin.com> (raw)
In-Reply-To: <20260524124456.350659-1-olek2@wp.pl>
Hello Aleksander,
> Armada 37xx has coherent bus, similar to Armada 7k/8k. Cache
> synchronization consumes a lot of CPU cycles. Enabling coherent DMA
> increases IOPS performance up to 4 times. Some numbers:
> Data length
> Algo MB 16 64 128 256 1024 1424 4096
> DES-ECB 1 +21 % +5 % +5 % +7 % +7 % +3 % +20 %
> AES-ECB-128 1 +21 % +6 % +6 % +6 % +9 % +8 % +22 %
> AES-CBC-128 1 +21 % +5 % +5 % +5 % +6 % +7 % +23 %
> AES-CBC-256 1 +23 % +7 % +8 % +6 % +11 % +13 % +20 %
>
> Data length
> Algo MB 16 64 256 512 1024 1420 4096 8192
> AES-GCM-128 1 +44 % +42 % +31 % +32 % +27 % +30 % +32 % +30 %
> AES-GCM-128 8 +319 % +326 % +163 % +148 % +75 % +72 % +74 % +41 %
> AES-GCM-128 4096 +123 % +128 % +90 % +83 % +116 % +59 % +38 % +28 %
>
> Data length
> Algo MB 16 64 256 1024 2048 4096 8192
> MD5 1 +21 % +15 % +29 % +25 % +50 % +16 % +20 %
> SHA1 1 +24 % +22 % +27 % +22 % +18 % +20 % +20 %
> SHA256 1 +30 % +24 % +25 % +26 % +21 % +41 % +19 %
> SHA512 1 +4 % +3 % +8 % +10 % +24 % +10 % +11 %
>
> Tested on Armada 3720. Platform passes testmgr selftests.
>
> Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
I'm surprised that we didn't enable it when submitting the support for
Armada 3700, but indeed the datasheet mentions I/O coherency support. I
didn't see any specific register to configure it. Moreover, if none of
the tests failed, we can assume that the bus is indeed coherent.
Applied on mvebu/dt64
Thanks,
Gregory
> ---
> arch/arm64/boot/dts/marvell/armada-37xx.dtsi | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm64/boot/dts/marvell/armada-37xx.dtsi b/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
> index 360fc24fdde2..8418777042b8 100644
> --- a/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
> +++ b/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
> @@ -437,6 +437,7 @@ crypto: crypto@90000 {
> interrupt-names = "ring0", "ring1", "ring2",
> "ring3", "eip", "mem";
> clocks = <&nb_periph_clk 15>;
> + dma-coherent;
> };
>
> rwtm: mailbox@b0000 {
> --
> 2.53.0
>
--
Grégory CLEMENT, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
prev parent reply other threads:[~2026-06-01 8:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-24 12:44 [PATCH] arm64: dts: marvell: armada-37xx: mark EIP97 as dma-coherent Aleksander Jan Bajkowski
2026-05-24 13:04 ` sashiko-bot
2026-06-01 8:08 ` Gregory CLEMENT [this message]
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