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From: Richard Schleich <rs@noreya.tech>
To: robh+dt@kernel.org, nsaenz@kernel.org, f.fainelli@gmail.com,
	bcm-kernel-feedback-list@broadcom.com,
	devicetree@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Cc: Richard Schleich <rs@noreya.tech>
Subject: [PATCH] ARM: dts: bcm2835/6: Add the missing L1/L2 cache information
Date: Sat,  5 Feb 2022 20:59:11 +0100	[thread overview]
Message-ID: <20220205195911.52578-1-rs@noreya.tech> (raw)

This patch adds the cache info for the BCM2835 and BCM2836.
However, while testing I noticed that this is
not implemented for ARMv6/7.
Basically arch/arm/kernel/cacheinfo.c and other topology
related code is missing.
Since the work is already done and this has no negative effects,
I am submitting it for future/documentation purposes.

Signed-off-by: Richard Schleich <rs@noreya.tech>
---
 arch/arm/boot/dts/bcm2835.dtsi | 17 ++++++++++++
 arch/arm/boot/dts/bcm2836.dtsi | 50 ++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)

diff --git a/arch/arm/boot/dts/bcm2835.dtsi b/arch/arm/boot/dts/bcm2835.dtsi
index 0549686134ea..1c90e5a44283 100644
--- a/arch/arm/boot/dts/bcm2835.dtsi
+++ b/arch/arm/boot/dts/bcm2835.dtsi
@@ -14,6 +14,23 @@ cpu@0 {
 			device_type = "cpu";
 			compatible = "arm,arm1176jzf-s";
 			reg = <0x0>;
+			/* Source for d/i-cache-line-size and d/i-cache-sets
+			 * https://developer.arm.com/documentation/ddi0301
+			 * /h/level-one-memory-system/cache-organization?lang=en
+			 *
+			 * Source for d/i-cache-size
+			 * https://forums.raspberrypi.com/viewtopic.php?t=98428
+			 *
+			 * NOTE: The BCM2835 has a L2 cache but it is dedicated to the GPU
+			 * It can be shared with the CPU through fw settings,
+			 * but this is not recommended.
+			 */
+			d-cache-size = <0x4000>;
+			d-cache-line-size = <16>;
+			d-cache-sets = <256>; // 16KiB(size)/16(line-size)=1024ways/4-way set
+			i-cache-size = <0x4000>;
+			i-cache-line-size = <16>;
+			i-cache-sets = <256>; // 16KiB(size)/16(line-size)=1024ways/4-way set
 		};
 	};
 
diff --git a/arch/arm/boot/dts/bcm2836.dtsi b/arch/arm/boot/dts/bcm2836.dtsi
index b390006aef79..534dacfc4dd5 100644
--- a/arch/arm/boot/dts/bcm2836.dtsi
+++ b/arch/arm/boot/dts/bcm2836.dtsi
@@ -41,11 +41,26 @@ cpus: cpus {
 		#size-cells = <0>;
 		enable-method = "brcm,bcm2836-smp";
 
+		/* Source for d/i-cache-line-size and d/i-cache-sets
+		 * https://developer.arm.com/documentation/ddi0464/f/L1-Memory-System
+		 * /About-the-L1-memory-system?lang=en
+		 *
+		 * Source for d/i-cache-size
+		 * https://forums.raspberrypi.com/viewtopic.php?t=98428
+		 */
+
 		v7_cpu0: cpu@0 {
 			device_type = "cpu";
 			compatible = "arm,cortex-a7";
 			reg = <0xf00>;
 			clock-frequency = <800000000>;
+			d-cache-size = <0x8000>;
+			d-cache-line-size = <64>;
+			d-cache-sets = <128>; // 32KiB(size)/64(line-size)=512ways/4-way set
+			i-cache-size = <0x8000>;
+			i-cache-line-size = <32>;
+			i-cache-sets = <512>; // 32KiB(size)/32(line-size)=1024ways/2-way set
+			next-level-cache = <&l2>;
 		};
 
 		v7_cpu1: cpu@1 {
@@ -53,6 +68,13 @@ v7_cpu1: cpu@1 {
 			compatible = "arm,cortex-a7";
 			reg = <0xf01>;
 			clock-frequency = <800000000>;
+			d-cache-size = <0x8000>;
+			d-cache-line-size = <64>;
+			d-cache-sets = <128>; // 32KiB(size)/64(line-size)=512ways/4-way set
+			i-cache-size = <0x8000>;
+			i-cache-line-size = <32>;
+			i-cache-sets = <512>; // 32KiB(size)/32(line-size)=1024ways/2-way set
+			next-level-cache = <&l2>;
 		};
 
 		v7_cpu2: cpu@2 {
@@ -60,6 +82,13 @@ v7_cpu2: cpu@2 {
 			compatible = "arm,cortex-a7";
 			reg = <0xf02>;
 			clock-frequency = <800000000>;
+			d-cache-size = <0x8000>;
+			d-cache-line-size = <64>;
+			d-cache-sets = <128>; // 32KiB(size)/64(line-size)=512ways/4-way set
+			i-cache-size = <0x8000>;
+			i-cache-line-size = <32>;
+			i-cache-sets = <512>; // 32KiB(size)/32(line-size)=1024ways/2-way set
+			next-level-cache = <&l2>;
 		};
 
 		v7_cpu3: cpu@3 {
@@ -67,6 +96,27 @@ v7_cpu3: cpu@3 {
 			compatible = "arm,cortex-a7";
 			reg = <0xf03>;
 			clock-frequency = <800000000>;
+			d-cache-size = <0x8000>;
+			d-cache-line-size = <64>;
+			d-cache-sets = <128>; // 32KiB(size)/64(line-size)=512ways/4-way set
+			i-cache-size = <0x8000>;
+			i-cache-line-size = <32>;
+			i-cache-sets = <512>; // 32KiB(size)/32(line-size)=1024ways/2-way set
+			next-level-cache = <&l2>;
+		};
+
+		/* Source for cache-line-size + cache-sets
+		 * https://developer.arm.com/documentation/ddi0464/f/L2-Memory-System
+		 * /About-the-L2-Memory-system?lang=en
+		 * Source for cache-size
+		 * https://forums.raspberrypi.com/viewtopic.php?t=98428
+		 */
+		l2: l2-cache0 {
+			compatible = "cache";
+			cache-size = <0x80000>;
+			cache-line-size = <64>;
+			cache-sets = <1024>; // 512KiB(size)/64(line-size)=8192ways/8-way set
+			cache-level = <2>;
 		};
 	};
 };
-- 
2.25.1


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             reply	other threads:[~2022-02-05 20:00 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-05 19:59 Richard Schleich [this message]
2022-02-11 22:24 ` [PATCH] ARM: dts: bcm2835/6: Add the missing L1/L2 cache information Florian Fainelli

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