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Date:   Wed, 18 Jan 2023 10:00:30 -0500
Mime-Version: 1.0
Message-ID: <20230118150030.2079226-1-aaelhaj@google.com>
Subject: [PATCH] arm: dts: aspeed: tyan s8036: enable kcs interrupts.
From:   Ali El-Haj-Mahmoud <aaelhaj@google.com>
To:     Rob Herring <robh+dt@kernel.org>, Joel Stanley <joel@jms.id.au>,
        Andrew Jeffery <andrew@aj.id.au>, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org
Cc:     aaelhaj@google.com, osk@google.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

When the BIOS is built with kcs interrupts enabled, not enabling
interrupts on the BMC results in very poor IPMI performance.
The other way around (BIOS with interrupts disabled, BMC with
interrupts enabled) doesn't suffer degraded IPMI performance.
Enabling interrupts on the BMC covers both scenarios, and should
be the default.

TESTED: manually verified IPMI performance when BIOS is built with and
without KCS interrupts.

Signed-off-by: Ali El-Haj-Mahmoud <aaelhaj@google.com>
---
 arch/arm/boot/dts/aspeed-bmc-tyan-s8036.dts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/boot/dts/aspeed-bmc-tyan-s8036.dts b/arch/arm/boot/dts/aspeed-bmc-tyan-s8036.dts
index 708ee78e4b83..f6c4549c0ac4 100644
--- a/arch/arm/boot/dts/aspeed-bmc-tyan-s8036.dts
+++ b/arch/arm/boot/dts/aspeed-bmc-tyan-s8036.dts
@@ -364,6 +364,7 @@ &kcs1 {
 &kcs3 {
 	status = "okay";
 	aspeed,lpc-io-reg = <0xca2>;
+	aspeed,lpc-interrupts = <1 IRQ_TYPE_LEVEL_HIGH>;
 };
 
 /* Enable BMC VGA output to show an early (pre-BIOS) boot screen */
-- 
2.39.0.314.g84b9a713c41-goog