On Fri, 3 May 2024 11:09:41 +0200 Dragan Simic <dsimic@xxxxxxxxxxx> wrote: > Add missing cache information to the Allwinner H616 SoC dtsi, to allow > the userspace, which includes lscpu(1) that uses the virtual files provided > by the kernel under the /sys/devices/system/cpu directory, to display the > proper H616 cache information. > > Adding the cache information to the H616 SoC dtsi also makes the following > warning message in the kernel log go away: > > cacheinfo: Unable to detect cache hierarchy for CPU 0 > > Rather conspicuously, almost no cache-related information is available in > the publicly available Allwinner H616 datasheet (version 1.0) and H616 user > manual (version 1.0). Thus, the cache parameters for the H616 SoC dtsi were > obtained and derived by hand from the cache size and layout specifications > found in the following technical reference manual, and from the cache size > and die revision hints available from the following community-provided data > and memory subsystem benchmarks: > > - ARM Cortex-A53 revision r0p4 TRM, version J > - Summary of the two available H616 die revisions and their differences > in cache sizes observed from the CSSIDR_EL1 register readouts, provided > by Andre Przywara [1][2] > - Tinymembench benchmark results of the H616-based OrangePi Zero 2 SBC, > provided by Thomas Kaiser [3] > > For future reference, here's a brief summary of the available documentation > and the community-provided data and memory subsystem benchmarks: > > - All caches employ the 64-byte cache line length > - Each Cortex-A53 core has 32 KB of L1 2-way, set-associative instruction > cache and 32 KB of L1 4-way, set-associative data cache > - The size of the L2 cache depends on the actual H616 die revision (there > are two die revisions), so the entire SoC can have either 256 KB or 1 MB > of unified L2 16-way, set-associative cache [1] > > Also for future reference, here's the relevant excerpt from the community- > provided H616 memory subsystem benchmark, [3] which confirms that 32 KB and > 256 KB are the L1 data and L2 cache sizes, respectively: > > block size : single random read / dual random read > 1024 : 0.0 ns / 0.0 ns > 2048 : 0.0 ns / 0.0 ns > 4096 : 0.0 ns / 0.0 ns > 8192 : 0.0 ns / 0.0 ns > 16384 : 0.0 ns / 0.0 ns > 32768 : 0.0 ns / 0.0 ns > 65536 : 4.3 ns / 7.3 ns > 131072 : 6.6 ns / 10.5 ns > 262144 : 9.8 ns / 15.2 ns > 524288 : 91.8 ns / 142.9 ns > 1048576 : 138.6 ns / 188.3 ns > 2097152 : 163.0 ns / 204.8 ns > 4194304 : 178.8 ns / 213.5 ns > 8388608 : 187.1 ns / 217.9 ns > 16777216 : 192.2 ns / 220.9 ns > 33554432 : 196.5 ns / 224.0 ns > 67108864 : 215.7 ns / 259.5 ns Thanks for dumping the elaborate information here! > The changes introduced to the H616 SoC dtsi by this patch specify 256 KB as > the L2 cache size. As outlined by Andre Przywara, [2] a follow-up TF-A patch > will perform runtime adjustment of the device tree data, making the correct > L2 cache size of 1 MB present in the device tree for the boards based on the > revision of H616 that actually provides 1 MB of L2 cache. I pushed that TF-A patch for review now: https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/28694/1 On my OrangePi Zero3 (with an 1MB H618 SoC) the size and number of sets get adjusted to describe 1MB: => fdt list /cpus/l2-cache l2-cache { compatible = "cache"; cache-level = <0x00000002>; cache-unified; cache-size = <0x00100000>; cache-line-size = <0x00000040>; cache-sets = <0x00000400>; phandle = <0x00000003>; }; > [1] https://lore.kernel.org/linux-sunxi/20240430114627.0cfcd14a@xxxxxxxxxxxxxxxxxxxxxxxxxxx/ > [2] https://lore.kernel.org/linux-sunxi/20240501103059.10a8f7de@xxxxxxxxxxxxxxxxxxxxxxxxxxx/ > [3] https://raw.githubusercontent.com/ThomasKaiser/sbc-bench/master/results/4knM.txt > > Suggested-by: Andre Przywara <andre.przywara@xxxxxxx> > Helped-by: Andre Przywara <andre.przywara@xxxxxxx> > Signed-off-by: Dragan Simic <dsimic@xxxxxxxxxxx> So I can confirm that the information above is correct, and also matches the DT properties added below. Reviewed-by: Andre Przywara <andre.przywara@xxxxxxx> Thanks! Andre > --- > .../arm64/boot/dts/allwinner/sun50i-h616.dtsi | 37 +++++++++++++++++++ > 1 file changed, 37 insertions(+) > > diff --git a/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi > index b2e85e52d1a1..4faed88d8909 100644 > --- a/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi > +++ b/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi > @@ -26,30 +26,67 @@ cpu0: cpu@0 { > reg = <0>; > enable-method = "psci"; > clocks = <&ccu CLK_CPUX>; > + i-cache-size = <0x8000>; > + i-cache-line-size = <64>; > + i-cache-sets = <256>; > + d-cache-size = <0x8000>; > + d-cache-line-size = <64>; > + d-cache-sets = <128>; > + next-level-cache = <&l2_cache>; > }; > > cpu1: cpu@1 { > compatible = "arm,cortex-a53"; > device_type = "cpu"; > reg = <1>; > enable-method = "psci"; > clocks = <&ccu CLK_CPUX>; > + i-cache-size = <0x8000>; > + i-cache-line-size = <64>; > + i-cache-sets = <256>; > + d-cache-size = <0x8000>; > + d-cache-line-size = <64>; > + d-cache-sets = <128>; > + next-level-cache = <&l2_cache>; > }; > > cpu2: cpu@2 { > compatible = "arm,cortex-a53"; > device_type = "cpu"; > reg = <2>; > enable-method = "psci"; > clocks = <&ccu CLK_CPUX>; > + i-cache-size = <0x8000>; > + i-cache-line-size = <64>; > + i-cache-sets = <256>; > + d-cache-size = <0x8000>; > + d-cache-line-size = <64>; > + d-cache-sets = <128>; > + next-level-cache = <&l2_cache>; > }; > > cpu3: cpu@3 { > compatible = "arm,cortex-a53"; > device_type = "cpu"; > reg = <3>; > enable-method = "psci"; > clocks = <&ccu CLK_CPUX>; > + i-cache-size = <0x8000>; > + i-cache-line-size = <64>; > + i-cache-sets = <256>; > + d-cache-size = <0x8000>; > + d-cache-line-size = <64>; > + d-cache-sets = <128>; > + next-level-cache = <&l2_cache>; > + }; > + > + l2_cache: l2-cache { > + compatible = "cache"; > + cache-level = <2>; > + cache-unified; > + cache-size = <0x40000>; > + cache-line-size = <64>; > + cache-sets = <256>; > }; > }; >
